The Folding Society

The Dahon Jetstream XP

Test report originally issued 22 July 2004


Introduction

Dahon is almost certainly the largest specialist folder company in the world, and has also been in the business for longer than most. Its earliest models were pretty basic, as were most folders at that time, but, especially over the last three years or so, they have introduced some much more sophisticated models. Their range is also very wide, in terms of both type and price - relatively cheap, simple folders, ultra light commuting folders, 'mid-range' general purpose machines, sporty models, mountain bikes and tourers, with wheel sizes of 16 inches, 20 inches, 26 inches and even 700Cs. Furthermore, there are updates every year, with existing models regularly being improved, and new models introduced. The Jetstream XP, which is the subject of this test. is a new model for 2004, towards the upper end of their range, and has many features to interest the folder enthusiast.

Although this is a 2004 model, and the range was introduced quite early in the year, it has only just become available in the UK, so although I was promised one by UK distributors Cyclemotion, its been quite a long wait. Was it worth it? Read on ...

I had the test bike for a couple of weeks, during which the opportunities for riding were restricted by the weather and then a very bad cold and chesty cough. The longest ride I did on it was a Brevet Populaire (BP), and this has already been reported elsewhere on the web site. There is quite a lot of overlap between that report and this article, but for the complete picture you do really need to read both - so either read the BP report after this, or read it now and come back here afterwards.

The specification

Some of the most striking features of the specification of the Jetstream XP are shown below - the full specification can be found on the Dahon web site:

Weight - 9Kg
Rear Suspension - Cane Creek rear shock
Front suspension - Pantour suspension hub (see www.pantourhub.com for more information on this hub)
Wheels/tyres - 20 inch 406 wheels, Rolf Dahon special, 16 spoke wheels, Dahon special edition Schwalbe Stelvio tyres
Gears - 9-speed Shimano Megarange derailleur, 11-32 sprockets, 52 tooth chainring (giving a 30 inch to 87 inch gear range)
Brakes - V-brakes

The most important claim of the specification is that this is the lightest full-suspension folder available. We will come back to this later ...

The Jetstream XP is attractively finished - almost all black, but frame highlights in silver and a golden orange, with orange bands either side of the centre tread of the tyre, and a rather bright orange centre stripe on the saddle (not very visible in this picture). The very long cables visible at the front of the bike are a bit ugly: they are not needed in folding, but allow for having the bars raised much higher (see below). The cable outers run all the way to the gears and brakes at the back, so water and dirt ingress should not be the problem it is with some folders, and the cable runs do not involve any sharp bends - another source of problems with some other folders.

The picture above shows the bike with the handlebars at their minimum height, and the saddle at the height I used, which as you might guess means the bars were just a fraction higher than I would like. The saddle will go a LOT lower! By contrast, the picture below shows both bars and saddle at maximum height (based on the warning marks on the stems)

In terms of size and fitting, the XP (as I will abbreviate it from now on to save effort!) almost anyone should be able to be adjust it to fit - handlebar height can be varied from 97cm to 110cm (personally I would have liked the bars lower, but it was acceptable with the bars this height) and the saddle from 84cm to 111cm. The seat post has markings every centimetre, to make it easier to re-position if the seatpost is lowered or removed in folding, or for different riders, but the steerer tube only has a maximum extension mark (you do not need to lower the bars when folding). In addition, the special saddle/seatpost mounting (which we will refer to again later) allows an exceptional fore and aft adjustment, which, together with saddle angle, is particularly easy to carry out using a side-accessible allen-headed bolt. Quick releases are used for both the seatpost and bar height adjustment - I just wish the tension adjustment nut had a Nyloc or similar fitting, as after a few releases you have to fiddle with the nut to get the right tension again, as any rotation will probably upset the setting (a minor niggle, and one common to almost all such QR fittings).

Potential market/users

The specification of this bike emphasises the extremely light weight, good ride, high quality and performance aspects, so we must bear this in mind when evaluating it. It is not intended to be the cheapest ultra compact commuting bike. I'd interpret its target market as being those who want a refined, comfortable high performance bike for typically half-day or day rides, but with a very effective folding capability, and the ability to be used for almost any other sort of ride as well when the need/inclination arises.

Frame

The all-aluminium frame of this bike is finished in gloss black, with silver and orange/gold highlights - it looks extremely smart and purposeful (see pictures above). A pot of retouching paint came with the bike - I actually used this, as the fold can result in some rubbing of the paint on the rear forks. This bike really is LIGHT - about 9Kg as claimed, with saddle and pedals, but no mudguards, which are an optional extra. I really appreciated the light weight when carrying the bike between station platforms, or just lifting it onto a train, into the house etc. Every other bike feels heavy now! Of course, the light weight is also appreciated when riding. There is plenty of adjustment for different rider sizes, as mentioned above. Mudguard fixing eyes are provided front and rear, and there is also a second set of mountings on the rear forks, which look as though they might be intended for a carrier (though it would be on the unsuspended part of the frame), though I'm not aware of a carrier being available to fit there at the moment. A couple of substantial mountings on the seat tube also look as though they might be intended for some form of carrier, but again I'm not aware of such an accessory being available at present.

The head set was a little tight and stiff when the bike was delivered, but this settled in quickly and then operated quite smoothly.

Suspension

The bike is billed as the lightest full-suspension folder, with the specification providing a Cane Creek rear shock and a Pantour suspension hub at the front. Neither would provided the amount of movement found on conventional mountain bikes, but would be expected to provide enough movement to soak up shocks during on-road riding, and some gentle off-roading as well. I was worried when I received the bike that the rear suspension seemed absolutely solid, but a ride around the block freed it. A simple means of adjusting the rear suspension to the rider weight and type of riding is provided by an air valve (Schraeder) on the shock - you need a suspension pump to pump this up, but I already had one for my Marin, so I was able to experiment mildly with this, and confirm that pressure can make a considerable difference. A table of suggested pressures v rider weights is supplied, and I found it quite appropriate for me. I am quite light, and heavier riders who tired the bike at this pressure were rather handicapped by the resultant excessive compression of the suspension - adjusting saddle height and bar height on this bike to allow someone else to use it is easy, but if they are very different in weight, you will really need to change the suspension pressure as well to produce a satisfactory ride. The instructions for the Cane Creek shock describe other possible adjustments to suspension characteristics, but these seem to involve dismantling it, so I didn't investigate further - performance was fine for me just using the pressure adjustment. I'll comment on the performance of the suspension on the road later.

Above: Rear suspension uses a Cane Creek shock absorber

At the front, the Pantour suspension hub is not being supplied in the UK market, which I only discovered shortly before the bike was delivered. I have quite mixed feelings about this - it clearly demolishes the claim to be the lightest full-suspension folder, but I had some reservations about possible problems. I would have welcomed the chance to try the Pantour hub though, just to see if the reservations that I had were justified or not, namely: mudguard clearances, keeping the brake blocks on the rims, and the effect if a bump is hit while braking, and how to mount a computer. So as yet I don't know if these really would be problems, and of course how effective this form of suspension may be. As there is no suspension hub, the Rolf wheel, with its limited number of spokes is not used at the front - instead there is a similar profile rim with 28 spokes and conventional spoke nipples, which I needed to tweak a little to improve the trueness of the wheel. I'll discuss the quality of the ride in more detail later, but I was very pleasantly surprised at how comfortable the front of the bike was even without suspension - the absence of the Pantour hub really was not an issue in this respect, unlike the very harsh ride which some small-wheeled folders give without front suspension. For those interested in the Pantour hub, you can find more information on their web site at www.pantourhub.com.

Wheels and tyres

This is a bike which uses the 20 inch/406 wheel tyre - not as compact when folded as the 16 inch wheeled folders, but generally regarded as giving a more stable ride, and a very wide range of tyres (though this is not really a problem with the 349 version of the 16 inch wheel nowadays). 

Above: The rear wheel, with the stylish Rolf rim, and just 16 spokes

The XP comes equipped with narrow wheels and tyres - the latter being a special edition of the 28-406 Schwalbe Stelvio, rated at up to 120psi. This tyre has only a light tread. My experience in the past of the Stelvio has been good - low rolling resistance, but remarkably good grip for such a narrow tyre run at high pressure. My SP Brompton was fitted with a Stelvio (16 inch of course) recently on the back in place of the previous Primo, and the tendency to lock the back wheel when braking even quite gently disappeared. Obviously such a  narrow, smooth, tyre is not particularly well suited to serious off-road riding, loose surfaces and mud, but as will be described later I used the bike on canal towpaths and cycle tracks in dry conditions without any problems. The narrow rims would preclude fitting very wide tyres, but tyres up to 1.5 inches wide should not be a problem. The Rolf rear wheel, with its profiled rim, has only 16 spokes; this does not sound a lot, but the suspension will of course help to absorb some shocks, and I was assured by Dahon that these wheels have been rigorously tested and have passed all forms of test with flying colours; the spokes are rather special too. For a conservative cyclist, though, there must remain a slight worry with so few spokes, and there must also be the suspicion that if one spoke failed the integrity of the wheel would be much more severely affected than if there were more spokes. The rear wheel was very true on the bike as supplied - just as well, as the nipples are not accessible for adjustment - presumably you have to take off the tyre, tube and rim-tape to get to them.

Above: Front wheel, 28 spokes and accessible spoke nipples. Note also the Dahon special edition Schwalbe Stelvio tyres

As already described, a conventional front hub was fitted on the test bike, with 28 spokes. The rim is similar in profile to the Rolf one at the rear, but the difference in number of spokes and the shiny spoke nipples at the front do unbalance the appearance of the bike a little.

I was pleased to see that Presta-valved tubes are used, not Schraeder, and the valve-holes in the rims are sized accordingly. It is much easier to get the required high pressures with these valves.

Gears

The bike is supplied with a single chainring of 52 teeth combined with a Shimano Megrarange cluster, 11-32 teeth, at the rear. This gives a gear range of about 30 inches to 88 inches. Personally I would have gone for the slightly wider range 11-34 - with a single chain ring, I want as much range as I can get at the back, and although the difference is small, it all helps, and I have never been able to discover any disadvantages, apart from a slightly larger, but still acceptable, step into bottom gear. The overall range is pretty good for general use, although for touring with a load in hilly country, or riding Audaxes etc, a wider range would help - but of course you can't go wider than this with a single chainring. Overall gearing is very much down to personal choice, and for my own personal strength, riding style, and the type of rides I do, I would probably have gone for about 10% lower gearing overall - but this is really just a matter of personal choice.

Above: 9-speed 11-32 rear gear cluster, and medium length arm on the SRAM mech, giving reasonable ground clearance.
Below: 52 tooth front chain ring, with metal side plates to provide not only rider protection, but helping to keep the chain in place.

Adjusting the overall gearing on a bike is usually a matter of the chain ring size. Unfortunately with folders there can sometimes be complications about changing the chainring - apart from the question of whether the ring itself can be changed, or a new crankset may be required, there is the problem that chain retention devices may not work properly if the ring sized is changed. The crankset used on the XP has the 52T ring bolted on, with metal plates on either side. As the bike uses a frame hinge, rather than the rear triangle swinging under when folding (as it does on many folders, such as the Brompton and Birdy) chain retention when folding is not an issue. However, as many people will know, modern multi-gear rear derailleurs when used with a single chainring at the front can have problems with the chain coming off, especially during upward changes, and at the higher end of the gears. This is not a new phenomenon - my 1984 Moulton AM7 was a devil in this respect. The problem seems greater with small wheeled bikes - perhaps relating to chain length etc. Anyway, the two plates on either side of the ring on the XP are probably there more to keep the chain on than to protect the rider from getting oily, and if you change to a larger ring, they would become ineffective, and with a smaller ring, there is a risk of them rubbing against the chain at the extreme ends of the gear range, so altering the overall gearing just by changing the ring may present some problems on this bike - though less so than on, for example, a Birdy, where the corresponding plates and a lug also have to keep the chain under control when folding.

By removing one of the side plates a second ring could be put on the front, but there is no specific mounting point provided to add a front changer. For general riding the range would be sufficient for me, but for some riders, and some types of ride I do, I might like the possibility of adding a second ring. Although Dahon don't seem to list any means of fitting the associated front changer mechanism yet, they tell me that in the USA there is an adapter to allow this to be done. If this is a significant factor for you, it would be advisable to confirm the availability of this.

The changer on the handlebars is a twist grip - short, positive movements, though quite stiff. The rear mechanism (SRAM) is fitted with a medium length arm, which easily handles the Megarange cluster, but still gives some ground clearance. It performed well on the road - I'll be commenting more on various issues associated with gearing when I come to reporting performance on the road.

Brakes

The V brakes seem to have relatively short arms, and bear a Dahon logo. They are operated from SRAM levers on the bars (with slightly 'naff-looking' silver-coloured casings). Overall they provide plenty of stopping power, and are very smooth and progressive, and require just the right amount of pressure - not heavy, but no real risk of locking a wheel too easily. Particularly welcome, and a function of the quality of the rims, was the smoothness even when new - none of the jolt once per wheel revolution which a poor rim joint causes on many new bikes. With the bars rather low, the cables tended to affect the centring of the front brakes, and I had to increase the spring tension a little to overcome this, and properly centre the front brake.

Above: Brake levers, carbon fibre handlebars, and comfortable cork grips

Other fittings

First of all, I'll deal with the three essential points of contact between rider and bike.

The bike is supplied with the MKS pedals which can be unclipped from mountings on the pedals. These seem a sensible choice for the bike, although in fact only one pedal projects at all when the bike is folded, and that not very much. They weren't actually fitted when the bike arrived (not even the mountings), and as I prefer SPD pedals, and regrettably there aren't any yet to fit these MKS mountings (apart from one set which enthusiast Chris Eley managed to fabricate for one of his bikes!) I substituted my own SPD pedals.

The handlebars are carbon fibre - very smart looking, light, and perhaps with some resilience, as I'll mention later. The internal diameter is quite small (ie the walls are quite thick), which is reassuring if you worry about carbon fibre, but it might make it difficult to mount some models of bar-end mirror which plug into the end of the bars - as this was a loan bike, I used a strap-on mirror anyway. The end plugs seemed a bit loose, and the one on the left, not protected by the mirror, came  adrift at some point in the test. I must put in a spare, but the small internal diameter means that most end plugs I have can't be forced in without some surgery. The bars are fitted with some very nice, thick, cork grips, which have just a trace of give in them, but are not spongy, and should not be unpleasant when wet.

Finally, on to the most sensitive point of contact between the rider and bike - the saddle. I was all set to replace the saddle with one of my favourites when the bike arrived (as I would usually do with a test bike, without even trying the supplied saddle), and then realised I couldn't. As standard, the bike is supplied with an exceptionally light seat pillar with a non-standard mounting at the top, which requires a different type of saddle - a single central 'rail' (a system referred to by the manufacturer as I-Beam), not the usual two-rail system. The system used is made by the American company SDG - you can see it at their web site at http://www.sdgusa.com/. I understand that there are other saddles available from SDG to fit this patented mounting, but the range must be more limited than the conventional twin rail system, and they must be much more difficult to obtain than 'normal' saddles, and if you have a favourite saddle (or make of saddle) like a Brooks, this is a potential problem. It's all down to weight saving, and the pillar, mounting and saddle provided are phenomenally light, but you will have to decide whether you can live with the limitations of available saddles which result. Actually, there is an alternative - apparently you can specify a heavier, standard seatpost, and then you can fit your own preferred saddle. The easiest solution would surely have been an adapter to fit the top of the post supplied with the bike which would have allowed a standard saddle with rails to be fitted - OK, at a cost in weight and elegance, but at least there would then be a choice - unfortunately such a device is not available. I'll comment on saddle comfort and design again later, but I think that if I were buying the bike, at least without the opportunity to see if I could live with the supplied saddle, I would opt for the heavier alternative conventional seatpost.

Bottle mounting bosses are a subject of annoyance on many folders - either there aren't any, only a single set, they are inconveniently placed etc. It's not entirely the bike manufacturers fault - it's often difficult to see where a cage could be put without interfering with the folding. Bike Friday are an honourable exception in this respect. On the Dahon, there is a single set of bosses below the main frame member, partially concealed by the cables running to the back. This isn't really an ideal position for a bottle - difficult to reach, and it's likely to get dirty, but at least there are bosses. I put a pump there, and was going to put the bottle cage on as well, but I found the tightly constrained cables there made it difficult to get it in place without bending the cables excessively, so I only put the pump there, and settled for carrying the bottle in a rear bag.

Coming back to the cable runs, these look a bit clumsy at the front with the bars low, as I had them, but if the bars are at maximum height, you can see that they really do need to be that long. If I owned the bike, I would be tempted to shorten the cables to suit my low bar position. The cables to the rear brakes and gears are sheathed all the way from the controls to the back, which will serve to prevent water and dirt getting in, and adversely affecting performance - a really serious problem with some other folders, some of which I have to re-cable at least once a year. The cable runs are also quite smooth - no sharp bends caused by the need to fold, which again can affect both braking and gear change performance on some folders. 

Folding and portability

This is quite a compact folder, but certainly more bulky than a Brompton when folded, and not quite as convenient to fold either. It's almost certainly bulkier than a Birdy when folded as well (I didn't have a Birdy around to be able to make the comparison during the test). However, personally I would rate the fold as much easier than a Birdy, and quite a lot of other compact folders - everything is quite obvious, there is almost nothing you can do wrong, it doesn't matter much what gear it is in and where the pedals are when you start the fold etc. Size and strength of the user are also not an issue - I didn't find it the battle that folding a Birdy, Bike Friday etc is for me. Tellingly, I have often remarked in the past that to me the acid test in folding is the fact that whatever the manufacturers or enthusiastic owners may say of a folder, only Brompton owners will willingly fold the bike even when they don't really need to. The XP performed very well in this respect - I actually folded voluntarily several times when travelling on trains, not during rush hours, the trains were not particularly full, and there were no restrictions on bike carriage. Perhaps I would not do this on a regular basis, but it held none of the fear and aggravation that folding some machines (Brompton obviously excepted) does. The light weight obviously does help in this respect. The fold is accomplished by using  three quick releases - one for the seat post, one for the main frame hinge and one to fold the bar assembly to the side of the bike. There are simple but effective additonal safety catches for both the main fraime hinge and the steerer/handlebar stem hinge.

    

Above left: Main frame hinge. Above right: handlebar assembly hinge

When folded, a simple Velcro strap holds the wheels together - the handlebars are not secured, but stay where you want them under the force of gravity. The bike looks reasonably tidy, and in most situations I don't think you would need to bag it - I didn't have the optional bag, but did carry a very light drop-over cover just in case. The chain is on the outside of the frame when folded, though the bars fold over it, providing some protection against getting oily; with the pump mounted below the frame, it was a bit awkward to find somewhere to grip the bike when carrying it - the Dahon bags usually have handles. You can't roll it along on its wheels when folded, but the light weight and ease of folding mean you would probably not want to do this much.

The Jetsteam XP, with an SP Brompton alongside for comparison. There is not a lot in the height (the XP shown here has the SQR bag mounting fitted, which stops the seatpost being fully lowered. Width is very similar, but the XP is quite a lot longer. The Brompton is certainly both smaller and neater in folded form, but I find the XP completely acceptable. Unfortunately the fitting of the SQR unit not only means the bike is a bit taller when folded, as the seatpost cannot be fully lowered, but the bottom of the seatpost is one of the points on which the bike stands when folded, so it won't balance very well when folded if the SQR is fitted - you might spot a brick in the background, which I used to support it in an upright position while taking the picture!

Overall, I thought this a very practical folding solution - if you commute into/out of London in the rush hour by train, it is not as convenient as a Brompton, but in most other situations it is not going to matter. Oh, and the bike very easily passed the 'Smart test'.

The Jetstream XP passed the Smart test very easily

Luggage

There are several mounting holes and brackets at the back of the bike that look as though they may have been put there with a view to mounting some form of luggage system, but at present the only accessories available are seatpost mounted carriers. One of these is the Carradice SQR system, which will take one of three very large wedge bags, or almost any saddle bag via a mounting unit. I regularly use this Carradice system, so that was what I fitted and used on the test bike. It is very robust, and with one of the really big Carradice saddlebags you would have quite a lot of space for luggage, though as with most Carradice products, it is a bit heavy - the price you pay for a really rugged design which should last a lifetime! The special SQR wedge bags also serve as a quite effective rear mudguard.

Even with the largest saddlebag, though, the lack at present of rear pannier carrier facilities and no front rack would be limiting for touring. A long weekend should be feasible (assuming B&B rather than camping), but a longer tour would become a problem - I'm assuming that you would, like myself, rule out any back pack as being unacceptable for comfort and stability. The available luggage options, such as the SQR system, should be adequate for shorter rides, weekends away, moderate shopping and commuting (though carrying a laptop computer might mean having to resort to a bag on the rider's back).

In fairness, I don't see this as primarily a touring model - the choice of tyres, wheels etc also mean that it is not the perfect tourer in standard form. Anyway, this is a new model for 2004, and there are some mounting points already on the bike, so more carrier options may materialise in time to make the bike even more versatile.

On the road

I had the bike on test for a couple of weeks, and during that time I tried to use it in as many different ways as possible:

I'll start with the quality of the ride. The rear suspension worked admirably, and was comfortable, without appearing to reduce pedalling efficiency. Especially when starting off, one occasionally got a distinct impression that one could feel the suspension give, but with no adverse effects. I'm quite light, and had the suspension pressure fairly low as a result, and others who tried the bike set like this clearly needed the pressure increased. One of these actually grounded a pedal while riding quite gently round a rather rough car park. The  bottom bracket and pedals are set quite low, and with suspension give, especially if the pressure is set for a lighter rider, the risk is increased. While riding along the length of a rutted towpath I myself caught the pedal on a rut once. In normal use I don't think this is a serious problem, but if you are a fast rider who likes to corner leaning well over, I think you would be well advised to take this into account and be suitably cautious. Although there was no front suspension and no suspension hub, I found the front end of the bike was very well behaved and extremely comfortable - quite unlike some other folders I have ridden which have similar sized wheels and no front suspension. I'm really not at all sure why the ride at the front is so good, but someone else who tried the bike confirmed my impression in this respect. I can only put it down to some combination of the cork handlebar grips (quite thick and very comfortable), carbon fibre handlebars, tyres, rear suspension and the slightly more upright riding position I was using, as the bars were a fraction higher than I would ideally position them. I would have no problems living with this bike in any riding conditions even without the front suspension. I did miss bar end extensions, to vary the riding position on a longer ride, but of course these are easily added if required. The bar width seems well chosen - wide enough to give excellent control, but without being excessive. You can adjust the saddle position to vary reach, but I would probably ideally have liked just a little bit of forward stem extension as well, and, as mentioned before, the minimum bar height was still perhaps a centimetre higher than I would ideally choose (I am very short, though). For most people, the range of seatpost and handlebar height adjustment, and fore and aft saddle adjustment should be perfectly adequate.

On-road the comfort was excellent, but it was also very good on the mild off road sections I tackled - a cycle path and twice along a 10Km stretch of towpath - not tarmac, but a reasonable surface, apart from some dreadful cobbled sections under bridges. On most bikes I dismount on these cobbled sections, but I was just able to keep going on the XP on the worst of them - a creditable performance by the bike.

In terms of handling, the bike felt just a fraction 'nervous' around the centre position of the steering - I'm a 'nervous' rider myself, and the narrow high-pressure tyres and light weight of the bike no doubt contribute - a relatively heavy Moulton APB on wider touring tyres is bound to feel more as though it will go over or through anything! The slightly stiff headset also affected the handling a little initially, but this soon settled in and was no problem thereafter. Stability felt very good, and fast descents could be tackled confidently, although perhaps not quite to the extent that I tackle them on the heavier Moulton APB with wider tyres - again, this is really to do with my riding style (or lack of it), not the bike. On the towpath, the bike handled well - it is not a particularly rough surface, and it was dry, but the Stelvio tyres handled these conditions without any problems at all. I managed to complete some rather awkward, tight turns on difficult surfaces without any problems - places where on some other bikes I prefer to dismount. Small wheels, a shortish wheelbase and good handling and stability certainly help here. Incidentally, having mentioned wheelbase, I did once or twice just manage to get the front wheel off the ground, but not to the extent that I had to take any correcting action. No doubt if you like to do wheelies, you could provoke them fairly easily, but it is not a problem in normal riding.

I had serious misgivings about the saddle - not that there looked anything wrong with the one fitted, but I do like to be able to fit my own choice, and the non-standard mounting ruled this out. In practice, I found the standard saddle fitted was not at all bad (for me!), and I could probably live with it. It didn't suit me as well as one of my favourite Brooks B17 Titaniums, but it was better than lots of other saddles, including the Flite Titaniums that I used to use regularly at one time. Having used it for some considerable distance in varying conditions, I think that if I were buying the bike I might decided to go for it and save the weight, but without having the experience, I would probably forgo the weight saving and opt for an alternative seat post which would take standard saddles. An oddity of the single rail design is that it is quite flexible in terms of rolling from side to side at the back. This is apparently quite deliberate, and supposed to increase comfort - I'm not entirely convinced on this, but it's one of those things that it is not easy to test.

The brakes performed admirably throughout, and, as mentioned before, the smoothness of any rim joints was a pleasant change from most new bikes. The brakes were smooth and progressive, and just about right in terms of effort required - you would not lock the rear wheel too easily, but the amount of force required on the levers is not high. I did just momentarily lock the rear wheel when confronted by a child riding towards me on the wrong side of a fairly busy road, and with no apparent sense of danger to himself or anyone else - it proves the brakes are powerful enough to do this, but that it is not too easy to do this, as is the case with some bikes I have ridden. Incidentally, this also confirms the view I had formed of the Stelvio tyre, based on using it in other sizes as well as the 406, that it has good grip in most conditions.

I have already discussed gear range and overall gearing - on the road, my expectations were confirmed, namely that for my general style of riding I would like the bike a shade lower geared overall, and that the range is fine for such general riding, though extending it from the 11-32 to 11-34 would be even better. I'd have liked to try it with an 11-34 cluster and a 48 tooth chainring, which would have been just about right for me. That brings me back to the possible problems of fitting a different sized chainring, due to the side plates. As already mentioned, a single ring, with no front derailleur, can result in problems keeping the chain on - this applies to most bikes, and small-wheelers seem particularly susceptible. If you look down at the chain while changing up, you will see why this is a problem - the top of the chain frequently thrashes from side to side during such upward gear changes. Moulton now fit a 'chain keeper' to their single ring AM and NS models which solves the problem - you can often hear the chain hit the keeper as you change gear, indicating that it is doing its job. Plates on either side of the chainring help, and in some folders, but not the XP, are also needed to keep the chain in place when folding. Unfortunately, they don't entirely solve the problem of keeping the chain on while riding, because the thrashing starts, or is at its worst, outside the area where the plates can control chain movement. I've had this problem to a greater or lesser extent with every derailleur geared single-chainring folder that I can recall using. Unfortunately the XP is no exception - I had the chain come off 3 times in about 270Km - far better than the worst offenders, but still enough to be a nuisance. Each time it happened, it was during an upward change, typically from 4th to 5th (on many bikes the problem is worst changing into top gear), when there was quite a light load on the chain, so not conditions which were obviously going to provoke problems. The chain fell between the ring and outer plate each time (as is usual with other bikes in this situation) - once it jammed there, twice it hung on to the edge of the teeth, giving drive, but a slightly odd sensation when pedalling, and a clinking noise - I immediately recognised this from past experience, especially with the Birdy Red. With a single chainring, fitting a dummy front derailleur, or a chain keeper style device, if there is a means of fitting either, is the best solution, and I wish that manufacturers in general, not just Dahon, would do this. On the XP, though, it occurs to me, looking at the bike, that I might be able to improve matters and deal with another issue at the same time. As the picture shows, the metal side plates actually are only just large enough in diameter to 'cover' the chain, and are reasonably well spaced from the ring. Normally, reducing the ring size and retaining the same plates is not possible as it causes the chain to rub against the plates at the extreme chain line angle of top and bottom gear (on my Birdy Reds, the chain was rather inclined to rub the inner plastic plate in bottom gear even with the standard ring!). I suspect on the XP, though, that I might be able to get away with a 50 or even 48 tooth ring without any problem of the chain rubbing, and this might just give enough additional support to the chain during upward changes to eliminate, or further reduce, the very occasional annoyance of dropping the chain. As the bike is only on loan, I haven't actually tried the experiment, so I'm not sure how effective it would be.

The weather was not especially good for much of the time that I had the bike, but I simply did not go out in these conditions, and only rode it once in really wet conditions. The Carradice Trax SQR rear bag mercifully saved me from suffering too much from spray thrown up from the back wheel, but there was no protection at the front. Although it adds weight, I would certainly fit the optional mudguards.

I folded the bike several times while I had it, both to put it in the car and on trains. In the latter case, this was not strictly necessary (not busy trains, and no restrictions on bike carriage). It is not the most compact fold, but is it so easy and straightforward that it is one of the very few bikes I would be prepared to fold even when I don't have to. The light weight of the bike is of course much appreciated when lifting and carrying it. The folded package is sufficiently neat and tidy that you should not need to use a cover in a lot of situations. This raises what I consider is an interesting issue - the importance, or not, of a VERY compact folded package. I can think of several folders which do fold a bit smaller, and possibly with some practice they may even be as quick, or quicker, to fold, but it is all too easy to get things wrong, and a lot of physical and mental effort is called for (well, bit of an exaggeration!), and most people avoid folding them if they can, especially in front of an audience! The XP may be less 'sophisticated' in the way it folds, but its is easy, and you would have difficulty getting it wrong. For the sort of folding I do - which is often, for trains and the back of the car, and sometimes putting it indoors -  the XP is preferable to a more compact fold which is a misery to carry out. The Brompton, or course, manages both the compact fold and the ease of folding, though it might be argued there are a few other compromises made to achieve this.

If you have not yet read my report on the 100Km Brevet Populaire which I did on the XP, do please read it now (or, if you like, later) as it adds some further comments on the performance of the bike on the road, one of which I must expand on in the next paragraph ...

While I had the bike on test, I had three punctures, one on the day of the Cheltenham Origami Ride, and two the next day, while riding a Brevet Populaire. To some, this might seem beyond the bounds of coincidence, and indicate a serious problem. However, as I have said in these web pages many times before, I'm inclined to regard punctures as largely a matter of luck - sometimes I can go for several weeks on various different bikes and different tyres and not get a puncture, and then get three punctures in a week, again on different bikes and tyres, and in different types of location as well. Three punctures in two days is rather more than usual though: one on a cycle track caused by a small flint (I think), another a piece of glass, and the last one exactly on the mould line of the replacement tube I fitted earlier - a Continental, and I've had problems with Continental tubes in the past, although with the valves rather than anything else. I think there is some doubt as to  whether that last 'puncture' really was a puncture in the normal sense or not. Anyway, in the interests of research I deliberately rode down two urban towpaths later in the test, over 10Km each time. There was clear evidence of broken glass in some places, and no doubt more elsewhere, even if it was not visible. I did not get any more punctures, The Stelvio tyres are a Dahon special edition, but any differences from standard Stelvios are likely to be minor, and I and others who have used standard Stelvios in this and other sizes have found them quite good in terms of puncture resistance and resistance to glass cuts etc. I really think we must put these punctures down again to bad luck - if you don't accept this, and/or want a heavier, more rugged tyre, there are several alternatives you could fit instead, which should still be quite satisfactory on the narrow rims, but you will lose the performance advantage of the Stelvio. I certainly won't be changing from the Stelvios on several of my own bikes as a result of this experience.

Conclusions

I had the bike on test for about two weeks, and during that period, it rose to third place in terms of distance covered on my own and other test bikes this year. Had it not been for rather poor weather, and a bad cold and cough, I'd probably have put in quite a lot more than the 270Km I finally clocked up (approximate, as I didn't have a computer fitted).

I thoroughly enjoyed riding the XP - it was comfortable, but was great fun to ride, very free running and a bike which encourages you to ride further and faster, if that is how you are feeling.

There are a few details of the specification which personally I would change, as described above, but overall I think that Dahon have put together another good package here. It's easy to lament the absence of the front suspension hub that was originally part of the specification, but even with a conventional hub fitted instead, I found the ride at the front was entirely acceptable - certainly better than other unsuspended front ends on small wheelers I have tried.

If you want the ultimate compact folder for commuting with train assistance in the rush hour in London, and a limited amount of riding, there are other more suitable and cheaper folders around - including some other Dahon models, of course. However, it is evident that this is not really the market at which this bike is aimed. This is a bike which performs very well on the road, but which folds extremely easily into a package which should be sufficiently compact for most people. For really fast road riding, it is not quite in the Airnimal/(some) Bike Friday league (if only because of the more limited range of gears resulting from a single ring), but it is much, much more portable than those models for train and car use.

The current seatpost mounted carrier systems may limit luggage capacity for touring, but the mountings on the frame suggest that this may improve later, and the character of the bike is more aimed at faster, lighter rides, perhaps day tours or weekends away, rather than serious touring, and Dahon have some other models more obviously suited to touring. They also have some cheaper, but less sophisticated, performance folders which may appeal to some readers - not to mention the more basic general purpose folders.

The finish of the bike is good, and general construction and component choice have evidently been made on the basis of quality, weight and performance - perhaps it would not be true to say that money was no object, but in no way has it compromised the specification and performance of the bike. The result is that this is quite expensive in Dahon terms - virtually 1000 in the UK, but still very competitive with lots of other high performance folders on the market.

Dahon have an excellent record for regularly improving their products, so I would not be surprised if the few areas which I found less than perfect are addressed in future product upgrades.

I occasionally muse on what I would choose if I could only have one bike - well, after trying the Jetstream XP, it would be a close run thing between it and an all-derailleur SP - the SP has the Brompton virtues of an exceptionally simple and compact fold and superb luggage system, enhanced by the silky smooth running, powerful V-brakes and derailleurs that Steve adds, but still with a less than ideal riding position; the Jetstream XP has the (for me) slightly preferable 20 inch/406 wheel, a better riding position, a wider gear range, really excellent rear suspension, it's much lighter and it's cheaper. Fortunately I don't have to make the decision at the moment.


Footnote

The 2004 Jetstream XP has only just become available here in the UK, so it is obviously rather early to start thinking about the 2005 models. However, we understand that Dahon are intending to allow the handlebars to be set lower if required, and there will be a magnetic catch (as used on some other Dahon models) to hold the frame together when folded. [24/07/2004]


Folding Society home page | Return to tests page | Dahon UK | Audax UK


Copyright ©2004 Ferrets Anonymous
Last updated 24 July 2004