The Folding Society

Using folders for longer rides

The Dahon Jetstream XP on the Blowingstone 100Km, 11 July 2004


This is the sixth of a series of tests of folding and separable cycles on longer rides in 2004 - see the introductory page for more background information. For this ride I used the Dahon Jetstream XP, a bike which I had on test for a couple of weeks. As this report is originally being published before the full test report on the bike, there is rather more about the bike than in some of the earlier ride reports, and there may be some overlap with the final test report on the bike.

Introduction

I think that the idea for doing this particular ride originated with that well-known folder rider Dave Minter, who did the 1200Km Paris-Brest-Paris in 2003 on a 2-speed 1965 Moulton Stowaway, and regularly rides Audaxes of various lengths. As this particular Brevet Populaire (BP) was taking place the day after the Cheltenham Origami Ride, it would be possible to combine the travel, and Dave, with his usual enthusiasm, managed to persuade four other folder fanatics to enter the event. This report will concentrate on my own experiences with the Dahon Jetstream XP, but I'll also refer to the others at various points, so here is the full list of the folder contingent:

Susan Barlow - Brompton, 5-speed Sturmey-Archer hub, plus SP double chainring conversion and SP sprung handlebar stem
Tony Hadland - Moulton APB, with 451 wheels (in place of the standard 406s) and 8-speed Sturmey-Archer hub gear
Dick Hanson - Moulton fx8, with double chainring
Myself - Dahon Jetstream XP, standard specification, apart from SPD pedals and rear bag
Dave Minter - Brompton, 5-speed Sturmey Archer hub gear

Because of the travel arrangements - Cheltenham on Saturday, then over to Farringdon after the Origami Ride, and return from there to different parts of the Midlands on Sunday - Dave and Susan drove down to Cheltenham in a hire car, and I used the Smart. After the Origami Ride on the Saturday, we motored over to Farringdon to stay overnight with Tony Hadland, who lives not far from Uffington, where the Sunday ride started. Dick Hanson motored over from Cheltenham for the Sunday start.

Planning and preparation

Cyclemotion, Dahon's UK distributor, originally offered me the opportunity to borrow a Jetstream XP for testing some weeks ago, but the bikes only recently arrived in this country, and the test bike reached me on 6 July. The weather was very poor for the next few days, so the combination of the Origami Ride on the 11th and this BP on the 12th were really the first opportunities to test the bike properly. After my experience earlier in the year, I would ideally choose a bike with a multiple chainring, to give a wider gear range, for a BP, but the opportunity for testing the Jetstream was too good to miss, and it also meant that I could make the Jetsteam available for inspection and testing by those on the Origami Ride.

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 presumably allow for having the bars raised much higher. 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 Dahon Jetstream XP is a new model this year - Dahon revise the model range and specifications every year, and have introduced a number of models of considerable interest to folder enthusiasts in recent years. The most striking features of the specification of the Jetstream XP are related to the claim that it is the lightest full-suspension folder. The full specification can be found on the Dahon web site, but, picking out the key features:

Weight - 9Kg
Rear Suspension - Cane Creek rear shock
Front suspension - Pantour suspension 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 (30 inch to 87 inch)
Brakes - V-brakes

As I am producing this ride report in parallel with a more detailed review of the bike, rather than describe and comment on the specification of the bike in detail here, the reader is referred to the review of the Dahon Jetstream XP for this information (the link will be inserted when the full report is available). I will refer below to just a few points regarding the specification which are of particular relevance to this ride.

As I only had the bike on test for 10 days or so, it was not practical or appropriate to modify it, as I would one of my own bikes, to suit my personal preferences and this particular ride. Thus I substituted Shimano SPD pedals for the supplied MKS quick release ones, fitted a Carradice SQR bag mount to the seat post, and strapped a mirror onto the bars, but decided I would have to manage without a map mount, computer and bar-end extensions, all of which I normally regard as nearly essential. Of more concern for a long ride was the fact that as soon as I came to substitute my preferred Brooks saddle for the one fitted to the bike, I realised this was impossible - the seatpost is fitted with a unique mounting requiring a special saddle (without conventional rails). This produces an exceptionally light seatpost and saddle, with an exceptionally wide range of adjustment for angle and horizontal movement, but at the expense of not allowing riders to fit their own preferred saddle. If an alternative adapter mounting for the seatpost were available, which would take a conventionally-railed saddle, you could make your own decision regarding weight versus personal choice, but there is apparently no such option, though an alternative seatpost can be specified which will take conventional saddles, but is heavier. Apparently there are a number of different saddles available to fit this mounting, but it seems probable that you would not be able to obtain them as easily as more conventional ones.

Once these bits had been fitted, it just remained to adjust the handlebar and saddle height, and the bike was ready. There is a huge range of seatpost height adjustment, as well as the exceptional saddle angle and reach adjustment mentioned above, and lots of adjustment for handlebar height as well - almost anyone should be able to fit comfortably on this bike, though I had to put the handlebars at the lowest position to suit my riding style.

I did not immediately spot the bottle bosses, which are beneath the main frame tube, under the rear brake and derailleur cables. These cables are well routed through loops on the frame, but unfortunately this makes it quite difficult to get at the bottle bosses, and to attach things without having to bend the cables quite sharply. In the end I just mounted a pump via the bosses, and mounted the bottle cage via flexible mountings on the long steerer tube. The under-frame mounting is not ideal for a bottle anyway - it cannot be reached while riding, and the bottle is going to get dirty there - still, better than no mounts at all, and many folders do not provide mounts Bike Friday are an honourable exception - lots of mounts and well positioned).

For the journey down to Cheltenham, I was able to fit the bike into the back of the Smart exceptionally easily - lots of room once the top of the luggage space had been folded back, but certainly no need to completely remove the separator.

The Jetstream XP passed the Smart test very easily

A bag is available to carry the bike in, but was not supplied with the test bike - I would not have bothered to use it for transporting the bike in the car anyway. Folding and unfolding is very easy any quick, and although not as compact as a Brompton when folded, this was not an issue for this journey. The frame and handlebar hinges are sturdy and reasonably easy to use, although I did have to fiddle to get the stem into position - the internal part of the catch does not seem to release far enough usually without some manual intervention.

As I was having to plan for events over two days, plus an overnight stay, I packed quite a lot of choices of clothing into the car.

Bad weather meant that I had done no more than ride the bike around the block a couple of times before taking it to Cheltenham for the ride on the Saturday before the BP, plus a slightly longer ride to Halfpenny Green Vineyard.  During the Cheltenham ride it became evident that the saddle was reasonably comfortable over short distances, but that, because the base is quite rigid, you do not want to sit far back on it, or the edges may dig into the top of your legs - I repositioned it accordingly before Sunday's ride. The Saturday ride was also very wet, and the absence of mudguards on the test bike was a drawback, mercifully alleviated by the fact that the Carradice SQR bag that I had fitted keeps the worst of the spray from the rear wheel from being thrown over the rider. The bike has mudguard mounts both front and rear, and I would personally definitely fit mudguards (which are available as an option), although again this obviously increases the weight. There are still some Audax events on which mudguards are compulsory, including two I have ridden myself this year - though I have never seen any check made, and on 'mudguard-compulsory' events I have seen riders without mudguards, including on one occasion the (eminent) organiser himself.

In addition to the mudguard securing holes, there are various other points at which rear racks might be attached. I'm told by Dahon that the two recommended rack/carrier solutions mount on the seatpost - Dahon's own "Tour rack" and the Carradice SQR, which is what I used.

On the Cheltenham Ride, I had a rear wheel puncture, caused apparently by a rather small flint picked up during a short ride along what most people would rate as a quite well surfaced cycle path. Still, as I commented at the time, I usually regard punctures as a matter of luck, and if I was going to get a puncture, I would rather get one on the gentle ride on Saturday than on the BP the next day. This was to prove to be a rather optimistic view of things, as we shall see later.

The ride

After the very wet weather on the Saturday ride at Cheltenham, the bike was fairly dirty, so first thing on Sunday I got it out and put a little oil on the gear mechanism and chain - there had been quite a lot of rain overnight, and it looked as though we would get more during the day. I also used the track pump, which I had fortuitously thought to bring with me, to put some more air in the rear tyre after the puncture on Saturday - it is very difficult to get near the 120psi rating of the tyres with the sort of hand pump which can be carried on the bike.

With every sign that it would be a wet day again, I decided to don shorts and a cycling top, with a choice of either a waterproof, but non-breathing, overjacket, or a non-waterproof, but breathing, overjacket. The bike came out of the car and unfolded very easily and quickly, and after signing on, there was a short wait before the countdown for the start. During this period it rained lightly, and the sky looked threatening, so we were all quite undecided about the best choice of clothing. I finally chose to stay with the shorts, and not even take the tracksuit bottoms in the capacious Carradice bag.

The folding group at the start - left to right: Dick Hanson, Dave Minter, Susan Barlow and Tony Hadland, all dressed, as you can see, in the height of fashion!

From the start it soon became evident that the route was going to be much hillier than I had expected, and to add to the difficulties, there was a brute of a hill very near the start. It was only with the greatest difficulty that I managed to get up without getting off and walking - some people were more sensible, and did walk. It was evident here that, at least for me, the Jetstream is a bit too high geared for this sort of ride - something that I had already concluded just be looking at the specification - and that a wider range of gears would be welcome.

Digressing ... For my normal riding, where I avoid quite such hilly routes, I reckon on wanting a bottom gear of below 30 inches, say about 28; for the hills often encountered on BPs, I am not sorry to have a bottom gear down in the low 20's. Top gear is then whatever I can get for this essential bottom gear - preferably over 80 inches, and ideally at least 90 inches for faster rides. Regular readers of my pages will know that I greatly favour a simple single chainring 9-speed Megarange of the kind used by the XP, but it is impossible to get the range I want for BPs from this, though it can be ideal for my own rides, where the steepest (up)hills are avoided (or walked), and I am quite prepared to coast down hills. While the overall gearing may be down to personal choice, the range is to some extent up to the bike manufacturer - the difference may be small, but I really do think that the 11-34 Megarange would have made a lot more sense than the 11-32 fitted to the XP, especially on a bike with a single chain ring. Personally I would want to go for a chainring of about 48, rather than 52, teeth - I really did not use top gear much, and I could have lived with coasting or not gaining maximum speed if the other side of the equation had been a lower bottom gear. But overall gearing does depend on the strength and riding style of the individual, so chain ring size is a personal matter. However, in this respect, it is nice if it is reasonably straightforward to change this. The XP has an interchangeable ring, so in this respect a smaller one could easily be fitted, but it may be difficult to obtain the appropriate alternative chainguard plates. These plates are not just there to keep the rider clean - if there is no front derailleur, it is often a serious problem that the chain sometimes falls off when changing gear with a bike with a single chainring. This is due primarily to the way the chain thrashes, especially during upward changes. Moulton finally solved this on their AM and NS bikes using a 'chain keeper', but other manufacturers don't seem to have adopted this simple yet effective solution. On the XP I had the chain come off the ring, and drop between the ring and outer guard - it produces an odd sensation, there is a clinking noise, but you still have drive, due to pressure between the chain/guard/ring. [Two days later the same thing happened, except this time the chain jammed, so that there was no drive]. This is NOT just a problem with this bike - I have had the same thing happen with a Birdy (many times) and as for the Bike Friday New World Tourist which I converted to a 9-speed Megarange, that was was a case of the chain coming off several times a day on an 8Km commute! Failing a chainkeeper, for a single chainring bike I would just fit a front derailleur mech - non-functioning, but keeping the chain under control. Although there is no specific mounting for such a mech on the Jetstream XP, apparently an adapter is available in the USA to mount a front changer, and with a second ring the gear range would be substantially widened. For my own normal riding, just lowering the gearing a shade would be my choice, plus some form of chain keeper, but for regular Audax use I would seriously consider fitting the adapter and second ring.

Personal views/prejudices, over, and back to the plot ...

I staggered to the top of that first hill in what was for me much too high a bottom gear (the VERY light weight of the XP was what saved me) - I watched with envy as Dick Hanson on his fx8 pulled away from me rapidly in a MUCH lower gear (he leaves me for dead on hills anyway - as he proved in Wales a few years ago on  a 3-speed Brompton, when I was on an 8-speed Birdy Red). On the other hand, I was amazed to pass a young lady riding a very nice conventional bike who was climbing steadily at probably less than half the cadence I was using - I would have fallen off at that speed and cadence, but she seemed to have no trouble, and rode much faster than I did once the hill was passed.

It was with some surprise that I managed (with some effort), to catch Dick again a bit later, and we rode together for a while, largely due to the fact that he moderated his speed, especially on hills, and I rode harder than I should have done so early in a long ride. As we came to the third steep hill, I suggested to Dick that he just go on ahead, but I managed to stay with him until near the top of the hill, when I became aware I had another rear puncture (I've already mentioned having one the previous day). Dick stopped, but there was clearly nothing he could do, so he acceded to my urgings to carry on, while I dealt with the problem. It was impressive that almost everyone who passed me asked if I was all right, or needed any help - one rider even offered a tube if I needed it (though as I was on 20 inch wheels and she was on 700Cs, it would not have solved my problem). Thank you everyone, I think you have restored my faith in human nature (well, at least some of the humans). My 'joke' to those passing me in my distress was that I had had a puncture the previous day, and that these things went in threes. Just as I finished repairing the puncture, the others in the folding group, who had been hindered by their much more severe gear-range problems, went past, and I was able to join up with them again. Dave of course could have left us all for dead, but on a ride like this he is quite happy to ride with the group, and offer support where needed - thanks Dave.

It is not easy to find time, and break the rhythm of the ride, to stop for photographs on a BP, but Susan could not resist this white horse

With a hand pump (even a Blackburn Airstick), I had probably only managed to get about 70psi into the rear tyre, which is my excuse for working quite hard to keep up with Tony (hasn't done an Audax for many years, and the APB and Sturmey-Archer 8-speed is heavy, whatever its other virtues) and Susan - not normally an Audax rider, and on a Brompton. We stayed together until after the first - and, unusually, only - control. We arrived at the control with some time to spare, but by the time we had refreshed ourselves, we were leaving just about on the time limit. Not too long after that, I experienced my SECOND puncture of the ride, and third of the weekend, which at least should have given me the satisfaction of knowing that my 'joke' about these things coming in threes had proved accurate.

Practice makes perfect, and this third rear puncture of the weekend was repaired reasonably quickly - there weren't all that many riders behind me by this stage, but once again I would like to thank all those (almost everyone) who slowed down and asked if I needed any help. I was seriously concerned at this point as to whether the delay would mean that I would fail to finish in the required time - this event had a minimum average speed of 15kph, which is rather higher than a lot of 100Km BPs. If you have never ridden one of these events, please don't sneer - it sounds quite low, but bear in mind that this is the average for the whole of a fairly long event, and has to include all stops - the average speed shown by your computer probably ignores stops, whether for a rest or just at a road junction.

At the back of the 'field' now, I had to balance riding reasonably quickly, in order to finish within the allotted time, with the need to avoid blowing up, and without anyone to follow to do the navigation for me. Fortunately, after riding into a head wind for much of the first part of the ride, I now had at least a neutral, if not supportive, wind (we all know how the wind usually changes direction during a ride, so that you are always riding into a head wind). I got a bit worried at one stage that I might have missed a turning, an especially important one, as it was an 'information control' point, at which I had to note a pub name (after the last event, I had remembered a pen, which not only helped here, but in marking the punctures on the tubes!). Not only did I finally arrive at this control in the end, but I caught up another rider, and was able to lend him my pen - psychologically quite encouraging. I kept working - and in terms of the report on the Jetstream XP, I must say that it is a great bike in these circumstances - and I very slowly pulled in and passed a few other riders. The climax of this was when I finally caught Tony, Susan and Dave, who had stopped on a steep hill (I had hoped to catch them earlier, especially when I was reduced to pushing on a particularly steep, if short, hill) for a breather. I'm afraid I was very antisocial at this point - I was going reasonably well, I feared ANOTHER puncture, and I also feared that if I stopped I might have trouble getting going again - so, with an apology, I kept going. From here, with a generally supportive wind, although my energy was beginning to fail, I was able to keep going at a reasonable pace to the finish, though at one point I got seriously worried again that I had missed a turning. On a loan bike, without the computer and map holder, I managed better than I expected, but I really missed these navigational accessories for this type of event.

I finally reached the finish point with a reasonable amount of time to spare, and was met by Dick, who had arrived half an hour earlier (despite stopping for an ice cream on the way!), and the other folders arrived very soon after, well within the time limit. Uffington provides, at a remarkably reasonable price, delicious teas, so we relaxed for a bit before returning to Tony's, and thence to our respective homes.

The absence of a computer and map holder on a bike which I had on loan for 10 days (it did not seem worth my while fitting them) meant that there were a couple of points at which I started worrying about the route, but the route sheet was excellent, as was the organisation in general. Based on the rides I have done so far, Shropshire and the Hartlebury BP were unbelievably good 'value for money', but this event, like the previous week's at Solihull, was brilliantly organised - heartfelt thanks to the organisers, who I know will have put in a lot of effort for no reward.

Comments on the ride and the performance of the Dahon Jetstream XP

I think that this is the first BP ride I have done with people that I knew before the event - it certainly enhances the experience. A big thank you to to the other folders, Dave, Susan, Tony and Dick, for making this an enjoyable experience. Dick's Cheltenham Origami Ride led up to this, so thank you to him and Hazel for that event, and the refreshments at the end. We are looking forward to Cheltenham 2005, when hopefully the weather will be back to normal. Thanks, too, to Tony and Rosemary Hadland for providing accommodation on Saturday night - sorry we didn't get time to talk about Life, the Universe and Everything, not to mention the MBC and computers!

I'd also like to thank the event organisers - this was a very well organised event, and one I'd be happy to do again, though I might want to make a few mods to the bike.

This leads to the question of how the bike performed. If I mentioned mods to the bike in the previous paragraph, I want to make it clear that this is largely a case of mods to suit me personally, and the type of ride. Bar end extensions, a computer, a map holder etc are not something you expect to find on a bike as part of its standard specification, nor would you necessarily WANT them to be, since personal choice comes into it. In the same vein, I'm sure you have heard the joke about the fact that if you are no good at your job/ speciality, you become a teacher, and, if you can't teach, you become a consultant. I'd add to that - if you are no good as a consultant, you become a critic! Actually, most critics haven't even done ANY of the preceding jobs, and as I suppose I could be regarded as falling into ALL of the categories, I'll just say that I TRY to take all this into account in the comments that follow.

Most importantly - did I enjoy using the bike on this event? An emphatic YES to this one, and, whatever comments follow, if this is the sort of folder you want, I thought it was very good indeed.

Portability
Although it is not in the Brompton class (what is?) in terms of compactness, the Jetstream folds very easily and quickly into a reasonably compact package, and a simple strap secures the frame in the folded position. It easily passed the 'Smart test', as the earlier picture shows. The extremely light weight is a real bonus when carrying it as well as when riding. I could easily live with doing multiple daily folds of this bike for commuting if the need arose.

Gears
I really like the single chainring 9-speed Megarange system for general riding, though I find it a bit lacking in the overall range for this sort of event - something that applies to any bike, and not just the Jetstream. The only answer is to use multiple chainrings - the Jetstream does not have a front mech mounting fitted, but I understand an adapter is available to fit one, and the crankset will accommodate a second ring. In my 'normal' riding, the single ring is preferable, but I would prefer to have a second ring for the odd occasions when I ride a BP. I don't really understand the reason for using the 11-32 cluster in place of the 11-34: yes, it means you don't have quite such a big jump in the gears going into bottom gear, but I think that most people would welcome providing a really low bottom gear for extreme conditions. Overall the gearing was a bit high for me - I would sacrifice a little at the top end to get a lower bottom gear, but that is an entirely personal matter. Fitting a 48 or 50 tooth ring in place of the 52 would be relatively simple, but might result in problems with rubbing on the two (metal) plates on either side of the ring. Single chainring derailleur systems with a large number of gears are notorious for problems with the chain coming off (at least with small-wheelers) - just watch the chain thrashing about as you change gear, particularly upwards in high gears, and you can see why. The plates reduce the risk of this happening, though I had the chain come off and slip between the outer plate and the ring on one occasion (not on this ride), which produces an odd sensation. [Two days later the chain came off between the ring and outer plate again, but this time it jammed solid; this was while pulling out gently from a side road, and changing from 4 to 5 or 5 to 6]. A medium-length arm rear mech is used, which is a good compromise in terms of ground clearance and handling the range of a 9-32 rear cluster. The gears are operated by a twist grip control on the bars, which is fairly stiff and has short movements, but is very positive. The gears always changed very sweetly and completely reliably.

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. Particularly welcome - and a function 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. The long, clumsy-looking cable run at the front of the bike (presumably to allow the bars to go to their full height, and not needed just to fold) tended to upset the centring of the front brake, and I had to both tweak a few of the spokes to true the front wheel, and adjust and increase the the spring tension on the brake adjuster to overcome rubbing on the front brake.

Ride and Handling
The head bearing was a bit tight and rough when the bike was delivered - very slight slackening of the headset improved matters, but it still felt rough. However, at the end of this ride everything felt fine, so it must have settled and run in quite well. With the stiff head bearing, the handling was slightly affected, but the initial adjustment overcame this. The very narrow, high pressure, Stelvio tyres resulted in quite fast/ responsive handling for a 406-wheeled bike, though I don't think that this would upset anyone buying this bike. There is lots of clearance for fitting fatter tyres if you feel so inclined, and the standard rims should be good for tyres up to 1.5 inches, 38mm, wide, such as the Marathon Slick, or the slightly narrower City Jet or City Marathon. The handlebar width is nicely chosen - wide enough to make the bike easier to control, without feeling uncomfortably wide. The carbon fibre bars and thick cork grips, plus the supple tyres, seem to give quite a comfortable ride from the front of the bike, despite the lack of any front suspension (see next paragraph). The rear suspension works well - no obvious sign of loss of energy due to bouncing when pedalling hard on hills, but obviously soaking up irregularities in the road surface. The only odd feature was that when starting off there was sometimes a distinct sensation of the rear suspension yielding. To make a comparison, my Bike Friday New World Tourist has a painfully (literally) harsh ride on the same sized, unsuspended, wheels, while the Jetstream feels fairly hard, but entirely acceptable on a bike of this type. Moulton suspension gives a more refined ride, but at the expense of more bounce and energy loss - I think the Jetstream has it right for the type of bike it is. [On a canal towpath ride two days later, the suspension performed exceptionally well - some of the cobbled sections under bridges are unrideable for me on most small-wheeled bikes, but on the Jetstream I managed without dismounting.] A nice feature is that, with a standard suspension pump, you can easily adjust the pressure in the rear shock to suit the rider's weight and whether you want a very firm, or rather softer, ride. This level of adjustment is greater, and easier to achieve, than on a Moulton, Birdy, or other folders using an elastomer in compression for rear suspension.

But what about 'the lightest fully suspended bike'? The spec refers to a Pantour suspension front hub, with a Rolf front wheel (with 16 spokes, like the back wheel). I remained to be convinced about the ride such a hub would give, but the more you think about suspension in the hub, the more concerned you get, at least from a theoretical point of view. What about keeping the brakes on the rim, the effect on handling if you brake while the rim is moving, mudguard clearances, operation of computers etc? At least in the UK, the bike is being supplied with a conventional, non-suspended, front hub, and a 28-spoke front wheel, similar in rim profile to the Rolf on the back. On the road, the ride was, as already mentioned, remarkably good for a non-suspended front end, in view of which I feel that the elimination of the possibly suspect front suspension hub is a good move. Even on a later towpath ride, I found the ride completely acceptable over about a 14Km distance. If you are buying in a market where the suspension front hub is fitted, please be aware of the potential problems it may raise, theoretically, as well as the potential advantage. The front wheel has conventional spoke nipples, so the slight tweak I did to true the wheel is simple - the Rolf back wheel has concealed nipples, so presumably if any truing is needed, you have to remove the tyre, tube and rim tape. I'm inclined to think that for a practical bicycle, this is taking weight saving to the extreme.

Personally I regard the standard seatpost/saddle combination (you can't fit other saddles, as mentioned above) as a limitation on the bike. Saddles are a very personal thing, and with this bike as supplied you have to accept the one fitted - there are apparently alternatives, but with no conventional saddle rails, you can't fit your favourite saddle. You may save weight this way, but I regard this as an too high a price to pay. The alternative would be to specify a different, and heavier seatpost - I would definitely do this myself. An alternative carbon fibre seatpost with a standard mounting is indeed available for those who share my prejudices! That said, the saddle supplied was not as uncomfortable as I feared it was going to be. With stops every 30Km or so, either for controls, or to fix punctures, I did not suffer unduly, and the next day there was no discomfort either. However, the hard edges at the bottom of the saddle mean that it is important not to sit even too far back on it - the range of horizontal and angular position helps in this respect, and adjustment is exceptionally easy, with a single, very accessible, allen-headed fixing bolt. I was not conscious of it at the time, but when examining the saddle after the ride I was surprised at the extent to which it can be bent from side to side at the back. This is apparently a deliberate design feature [Joshua Hon refers to this in following way: 'The saddle rolls from side to side with the riders pelvis - we call this feature TorsionFlex and it adds quite a bit of comfort by eliminating concentrations of pressure'].

Handling always felt quite quick - perhaps a bit more than some riders would want, but not out of keeping with a light, performance bike of this kind. I am a nervous rider, and don't descend hills well at speed (I have had serious problems with 'shimmy' on some bikes in the past). If you don't know what I mean by this, it is a situation where the rider responds to a real or perceived problem by moving the bars, and this produces too much response, resulting in a further over-compensation, which builds up in an alarming way. It's partly a characteristic of the bike, but riding style and weight added on bags at the front can make matters worse. If you have the problem, don't put any additional weight on the front of the bike (eg carriers) and fit wider handlebars if you can. The Jetstream is pretty good in this respect, even with me riding, but I needed to be a bit more cautious than on some bikes. Less nervous and twitchy riders will probably never notice any problem at all. [Two days after this ride, when I used the bike on a canal towpath, where some tight, low-speed manoeuvres were required, it handled exceptionally well - I managed some turns where I usually dismount or at lest put a foot down on other bikes.]

On the Saturday, Dick Hanson rode the bike fairly gently round the car park, and commented that the bottom bracket is rather low - he grounded a pedal (this was with my SPD pedals, which are slightly smaller than the standard ones supplied with the bike). However, the pressure in the rear shock was set for someone of my weight, and Dick is heavier than I am - with the correct pressure in the shock, the risk of this happening will be reduced. On a rough section of the towpath a couple of days later I also managed to ground a pedal. I wouldn't expect it to be much of a problem for most people, but it is as well to be aware of this if you corner fast and lean over a lot.

Overall, the handling was very good, and well suited to a bike of this type. Likewise, I think the ride, even without the originally planned suspension hub, is more than acceptable, and in keeping with a bike of this type.

Performance
This is an exhilarating bike to ride quickly and over longer distances. For a ride of this type, personally I needed a larger range of gears (only achievable by fitting more chainrings, for which there is no provision), and in particular I would sacrifice a little at the top end for more low gears. Towards the end of the ride, despite the fact that I was tiring, I found it relatively easy to keep pushing on - from past experience, the bike is a really important element in this, some bikes encourage the rider, and others seem to discourage.

Other equipment
The SQR bag again proved ideal, apart from the rather substantial weight, which is rather out of keeping with a bike like this. 

I really missed my map holder, computer and bar ends, which I was not able to fit to a bike which I only had on test for a short while. As a further comment on the ride and performance of the bike, although the bar ends were missed, I suffered less from the single riding position than I had expected.

Conclusions

Please note that is is primarily a ride report/test - I will be addressing some details of the specification and features of the bike in the full test report, which will appear not long after this ride report.

The Dahon Jetstream XP has an extremely attractive specification, and although it is not particularly expensive, at 999, it is bound to be judged according to the very high potential which it seems to offer. Perhaps the major claim of the spec is that it is the lightest full suspension folder. The original spec of the bike was for a Pantour front suspension hub - this would have appeared to have some potential theoretical problems, so its elimination (in the UK market at least) may destroy the major claim for fame of the bike, but is not without some benefits. Even without any front suspension, the front end of the bike gave an entirely acceptable ride -  and the (adjustable) rear suspension was fairly firm, but absorbed the pain of rough roads, and was in keeping with what I perceive as the character of the bike. The bike is certainly stunningly light, though the absence of mudguards, and the single chainring do of course help when comparing its weight with some competitors.

Handling was in keeping with a bike of this kind, and the brakes were also well up to the job. It was unquestionably an exhilarating bike to ride, and it encouraged the rider to keep going, and put in more effort when needed.

Portability is good - not the most compact folder, but exceptionally easy and quick to fold, and an easy fit in most cars, or on trains. A measure of the ease of folding is that two days later I did this to carry it on a train, even though it was not actually necessary to fold. In folded form, it is fairly neat, and I would not expect to need to bag it normally on a train.

I've referred to 'this type of bike', and potential buyers in the report, and this is, I feel, a critical issue. Dahon have a remarkable range of different folders, and the differences are in many case more than just the choice of components. This is in some respects a strength, but it does have a down side as well. The strong focus towards particular market sectors means you may be able to buy just the bike you want, but for many it may also limit to some extent  the potential for customisation to exactly fit the unique requirements of the individual owner. I can certainly relate to the specification of the Jetstream XP - in fact, in many respects it might have been specifically aimed at me, though there are a few features which seem to me inappropriate. Clearly, the major feature of the design is its low weight, but with suspension (which of course adds some weight!). In some respects, I feel that weight saving has been taken a bit too far - the seatpost and saddle system is very light, but, at least for me, doing this at the expense of significantly limiting the choice of saddle is going too far. If you have the option, I would seriously consider specifying the alternative carbon fibre seatpost which will take a standard saddle, even if this sacrifices some weight and the supplied saddle is reasonably good.

Heavier or harder riders might have concerns about a 16-spoke rear wheel. Weight saved on the wheel is generally reckoned to be more important than weight saved elsewhere, but, despite assurances that the wheel has passed very rigorous tests, personally I feel a little nervous, and with so few spokes, any breakage is likely to be catastrophic. I used to worry about those Moultons with 'only' 20 spokes!

Personally I really like the Megarange 11-34 gear system - it is a bit limited compared with multiple chainrings for heavy touring or Audaxes, but the saving in weight and complexity compensate for this. I just don't really understand why Dahon went for the 11-32, rather than the 11-34, a small difference, but critical when faced with a steep hill. Personally I'd lower the overall gearing as well, but that is a choice for the individual. Like all single chainring, multiple rear derailleur systems, keeping the chain on is a potential problem, which the Dahon handles quite well, but I prefer a 'chain keeper' to plates on the chainring, and not only is this lighter and, in my experience, more effective, but, assuming it is adjustable, it makes it less of a problem to change the chainring size to suit the rider's overall gearing preferences.

I must comment on the problems I had with punctures. I have frequently mentioned in the past that I regard punctures as largely a matter of luck. On the Saturday before this ride, I said to people that I would rather have the puncture then than on the longer Sunday ride. When I had the first puncture on the Sunday, I jokingly said to people that I was worried that these things go in threes - then later I had the third puncture! I have used Stelvios on other bikes and have found them excellent, and not particularly puncture prone. Chris Eley, who has now fitted 16 inch Stelvios to his SP, reports that he has had far fewer punctures since he changed from Brompton tyres to Stelvios. The Stelvio fitted to the Dahon is a 'special edition' - it has orange stripes on, which co-ordinate nicely with the colour scheme (forgot to mention this before, but the bike is generally regarded as being very attractively finished - black with some small golden orange highlights, and brighter orange flashes on the saddle and tyres) - and it has a Kevlar bead (interesting, it can roll as you persuade the last bit of the tyre onto the rim after a puncture). Although 3 punctures in three days seems potentially more than a coincidence, I'm still rather inclined to think that is what it was, particularly as there was no particular sign of what caused the third puncture, and it was on exactly on the (inside) moulding line of the tube, a Continental which I fitted after the second puncture - I have had unhappy experiences with Continental tubes in the past. Two days after this ride I used the bike on a 14Km ride along an urban canal towpath, with a fair amount of broken glass on it, and had no punctures, which further supports my feeling that the three punctures in two days were just bad luck. For those who want to do so, it is possible to fit rather more substantial tyres, as there is a good range in the 406 size, and there are the clearances to enable this to be done.

Please don't misunderstand the criticisms above - there are many folders (or indeed bikes in general) which fall so far short of what I regard as desirable that it is not worth dwelling on any weaknesses. I think the Jetstream XP is a great bike, and I can't imagine any owner not enjoying it. The points I have mentioned are just what are, for me, minor niggles which mean that it is not the perfect bike for me - and no other manufacturer has MY perfect bike either. If I could only have one bike, this would be a very strong contender.

Finally I'd like to thank Mark Bickerton of UK distributors Cyclemotion for lending me the bike, and also thank him and Joshua Hon of Dahon for providing feedback, corrections, and additional information to make this report more complete and more accurate.


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Last updated 14 July 2004