Whoa..that really sucks. I believe another Swift owner here encountered the exact same frame failure using a non-standard seatpost. Have you been using the stock seatpost?

Xootr warrants the frame for life, so you shouldn't have any problems getting a replacement. It's just too bad this happened in the middle of a long weekend. Just hang in there.

Thanks for the kind words, James. It does suck that it happened on a long weekend of rare nice New England weather.

I've been using the standard seatpost.

I seem to remember you had a frame failure. If that's right, was it at all like mine? How did Xootr deal with the warranty issue?

Jonathan

My frame failure was a crack at the lower seat tube clamp area (due to a manufacturing error, the tube had been honed eccentric, one side being thinner than the other). I emailed Xootr with a photo, and I received an email response 30 minutes later confirming that they would be shipping me a new bike. I'm confident they will do the same for you.

Whoa. That is the second Xootr that failed like that. Now I am leery of the design...

The other failure was here
http://www.bikeforums.net/showthread...lighter&page=3 post #67

Shhh. Jur, you weren't supposed to tell anybody. James_Swift has already given me enough grief... :D

Looking at his pic, looks like he has one of the thinner walled seat tubes. I seem to remember that they increased wall thickness.

Thicker post.

Jur, as for the design, do you think this is the price of not having a proper downtube?

I'm thinking of going the BikeFriday route for the front derailleur now. Since I've moved to the Bay Area/San Francisco, the number of hills has increased dramatically. I'll probably pull a james_swift and convert the swift to a fixie.

I think so, yes.

Riding my Swift, I am amazed by the vertical compliance of the frame, ie riding over bumps does not transmit the shocks sharply as with a diamond frame, it feels like I have soft tyres, but I don't - they are at 100psi. So I have been thinking about what gives the 'give', and it must be a combination of the top tube bending and the seatpost+seat tube bending.

Top tube bending is OK, but the seat post flexing places a stretching stress on that chainstay where it is welded. And now we have 2 cases of failure (and perhaps more unreported ones?) in exactly that spot of maximum stress.

For those cases of failure, an important data point would be to know ho much the seat post extended into the bottom portion of the seat tube? Could you have a check to see what this dimension might have been? I am thinking along the lines of only a short extension past the seat tube joint, resulting in insufficient strengthening given by the seat post.

Very interesting. I'm wondering if it's a design flaw, or a flaw in the materials/manufacturing? In any case, I'm keeping a close watch on my frame. Riding a fixed-gear up hills in San Francisco that one normally wouldn't without lower gears I'd imagine places huge amounts of stress on the seat tube/stays, as well as the bottom bracket. I'm actually more concerned about the really choppy road and deep potholes I have to ride through on a daily basis, and try to avoid them as much as possible, and/or unweight the seat for those which are unavoidable. I'm happy to say, however, that the frame has held-up perfectly to all my abuse.

With my current saddle height, I have a good 10 inches of seat post insertion into the seat tube. Upon inspection of the seat post, however, there are clear indications of friction marks that extend a few inches up from end of the post, possible evidence that the "truss" assembly does indeed pivot/flex slightly during riding. Is it possible that as the friction on the seatpost begins to wear-away the material, the extra play between the bore of the seat tube and the seatpost allows increased flex in the truss assembly, eventually causing the seat stays to bend beyond their breaking point? And if so, does this mean we need to replace our seatposts when they start to show excessive wear? That would suck.

[QUOTE=creaturely;5177891

My one issue has been with dropping my chain-- usually (but not always) while shifting; if not then, then over a bump or through a pothole. I gather that this is a common problem with a single front ring setup (though once the drop was off the big ring of the cassette rather than off the front!). But it seems to be getting more frequent-- at least once a ride, sometimes twice. Has anyone else experienced this, and if so, what are my options? I gather there is some kind of roller device? I'd rather avoid hanging something off the bike if I can avoid it (if I can't, I can't). Would shortening the chain help. or would it just make it that much harder to put the chain back on when it pops off? Any advice would be much appreciated.[/QUOTE]

I've been through three Dahons that had too long chains. Once the length was adjusted I never experienced a drop-off, even on the bike with no ring guard. Also check for deformed/worn chain rings and that your rear hub is square with the frame.

The seat posts are anodized, but the frame is not, so it would wear faster on the inside of the seat tube.

This issue emphasises the importance of doing up the seat QRs firmly, so the seatpost is gripped tightly by both with very little scope for movement.

Good advice.. I usually make sure each QR grips the post firm enough to keep the post from rotating on their own. then I cinch them both down... I've been using a 34mm Carbon post of over a year now without incident, but I'll pay particular attention now ..

metal fatigue
 

The whole frame failure idea with aluminum is what kept me from purchasing a Swift. I would have to get a steel frame regardless. Manufacturing tolerances are fairly broad when it comes to seat posts in my experience. The I.D. of the frame hole might be larger in one bike over another and the seat posts might be smaller by a few thousandths. This would make for a sloppy fit and after enough cycles of creaky seat post, that aluminum will just crack in half. If I ever end up with a Swift, it will be a steel bike and a custom fitted seat post that I know is machined round for a precision fit. This is the only weak point in the design of the swift frame that I can see, other than the choice of material.
Perhaps the builder could beef up the frame with larger diameter aluminum and epoxy steel sleeves inside for the seat post. These could be closer tolerance and force the often warped, post welded tubing, round to create a true round hole for the seat post to slide into. All that folding and unfolding over time will make a sloppy fit causing early failure with heavier riders.......maybe user replaceable bushings/sleeves etc. could be engineered to maintain a tight fit and account for wear.

Why are you leery of the design (instead of the implementation?)

The steel Swift Folders have been around for about a decade and this doesn't seem to be a common failure with them.

While I don't want to get deep into a steel vs alum for frame material debate, I understand that alum is not per se weaker than steel if you stay withing its elastic limits. It's just that for alum, the elastic limits are much smaller, right? So the idea of a precision fitting seatpost which limits movement sounds good.

On the other hand, Xootr does have a life guarantee on the frame. They wouldn't offer that if there was a low confidence on the frame life, would they?

Looking at the design, it seems to me that the QR on the top section of seat tube would be better placed at the joint instead of at the top. Placing it at the joint would provide better holding of the seat post accross the joint.

Another mode of flexing which hasn't occurred to me before, is torsional movement of the seat post, with the seat tube section rotating wrt the other at the joint. This would compress one strut and stretch the other. Or if one of the QRs is not very tight, it would allow slip, allowing the post to rotate inside the seat tube.

Making sure the Q/Rs are tight is obviously important. I always tighten the top Q/R first (having set the seat height) then put my weight onto the seat as I close the bottom Q/R. This ensures that both parts of the frame are pushed tight with each other. I don't know if this makes much difference but it keeps me happy! The Swift is such a great little bike I hope the cases of frame failure are isolated ones. It will be interesting to hear what Xootr have to say about the subject.

A Lion in Winter
 

San Francisco, Hawaii, Australia-- so lovely but ao temperate! So any of you hardcore longtime Swift riders live in lands of snow and ice? Today is a beautiful day, but in Chicago you can smell winter around the corner. How will my Swift handle in snow and ice? Do I need to buy what everyone regards as the fairly lame Innova studded tires that (as far as I can tell) are the only options for a 20 in bike? Or will some bmx knobblies do the trick? Reverse treads, as Peter White seems to suggest?

Any other tips for riding a little bike through winter?

Someone with experince in the white stuff, please advise!

I wasn't trying to start a steel vs aluminum debate. The failures mentioned here don't have anything to do with the material. It sounds like a couple of examples of the aluminum frame have had less precise seatpost machining which has created ovalized seatpost holes.

Hi There,

Anybody have an established locking system for the swift (other than, "take it inside with you")? I've realized that though the rear triangle is lockable, someone could take my top tube and fork, while leaving the triangle and cabled wheels. (Assuming they have a wrench)

One crafty solution might be to fashion some sort of facade that covers up the hinge so it isn't very evident- anybody try that?

Thanks,

GR

Just had a look at some of your blogs, almost looks like you & I came from the same mould! :)

The fitment tolerance of the seatpost is indeed to be closely scrutinised. It is obviously (with hindsight) a critical parameter. (The debate remark was actually aimed at the post just before yours...)

design
 

The design of the Swift is excellent except that the material choice at a critical pivot point lends itself to premature wear. It kind of rubs me the wrong way ( no puns intended ) when I see the application of aluminum with high wear areas. The use of steel or some other harder material as a bushing for a steel sleeved seat post makes more sense to me, rather than just letting a aluminum post slide in a aluminum hole. If the bike was rarely or never folded, the current configuration would be fine, assuming a good fitting seat post and tight clamping levers. The re-engineering of the alum. Swift would add to the price but it may be worth it, long term. Instead, I'd just make the bike out of steel since the weight penalties wouldn't amount to much, considering the fact that most riders are at least 5 pounds from ideal weight anyway.

And, of course, it is available in steel. Seems your concerns are of the result of the trade-offs of mass production in aluminum. Cheaper is not always better overall.

Have you considered a SRAM DualDrive hub in the back? That gives you a 3 speed internal hub X whatever number of cogs you have on the cassette. On my Dahon SpeedPro, I get 25-125 gear inches - more than enough! They cost about $200, much less than a Bike Friday :).

Two words Heav-y. ;)

I'm trying to keep the bike in the 9kg/20 lb. range.

Can't argue that one :(...

right on
 

That seems to be true in this case. I know the Swift is available in Steel. For most people, I think the Aluminum bike is probably alright, especially for lighter riders. Its interesting that some have made the ultralight SS/FG work nicely as a commuter and I can't argue with the lightweight thinking on that. I think a more utilitarian machine with an internal hub would be a better all around commuter. Of course this is what a folder is about I presume.

FWIW, both Brompton and most Dahons use a thin plastic sleeve to avoid direct metal-to-metal contact. Swift owners may be able to use these (maybe cut down to size), they cost very little. Obviously the next sized down seat post would then be needed. I have wrecked several aluminium seat posts on non folding bikes - where they have 'picked up' or sort of welded themselves to aluminium seat tubes. When released they have made huge scratches. On a folding bike where this is done upto 4 times a day avoiding this is critical.

I wouldn't trust a plastic sleeve unless it was approved by the designers. But I agree with what you say, I have considered it.

I may compose a letter to Peter Reich and hear what he has to say about these failures. Perhaps it is a storm in a tea cup.

Excellent idea. An electronic petition of some sort where those concerned can sign their names as well (count me in). ;)

It was the failure of the seat stays on my Xootr Swift frame (see here ) that prompted the most recent discussion of the frame.

Just a quick update on the response from Xootr. I'd emailed Xootr over the holiday weekend so wasn't expecting a response until the start of work today. Unlike James I wasn't emailed back within 30 minutes or at all. I called just after noon and was told that the person who was usually in charge was on vacation but that someone should be around at 4:00 who might be able to help. I'll get back with more information when I have any.

Jonathan

Good news!. I got in touch with the very nice people at Xootr, and they're sending me a whole new bike with pretty much no questions asked. :D

Brian, the person I reached, explained that they'd had some instances of breakage and so now were making the bike with thicker tubing, which has increased the overall weight by about a pound.

I am not an engineer and can't comment on the long term stability of the design, but their willingness to stand behind the frame inspires confidence in me, and I really, really like the way the Xootr Swift rides, folds and takes standard parts.

Jonathan