The Swifts were designed for 33.9mm posts, but the build-up of tolerance requires reaming of the seat tubes to make the post go in both. The unfortunate result is loose fitting posts. Tightening the clamps till they clamp securely can result in failure. My new black frame is like that, I have to tighten the heck out of the QRs. A shim is probably a good idea.

that's too bad, although not unexpected based on my experiences with dahons. aluminum on aluminum = short life and quick to wallow out.

steel or titanium is the way to go with this design.

Human Powered Machines » The Swift Folder

I wonder if a blind section of seat post, dropped into the seat tube,
wouldn't hold up the main seat post, with very low QR torque.

. . .

The idea is that the Swift has an adjustable height seat post.
This means that some (arbitrary) length of seat post may
safely be withdrawn from the seat tube.

I'm proposing to make up that length with a second piece
(of 33.9mm seat post) that resides somewhat permanently,
in the bottom of the seat tube.

The (mobile) seat post would then rest atop the semi-
permanent section.

If the semi-permanent section may fall out the bottom, a
small fixing bolt would prevent it from doing so. Looks like
the bottom bracket tube (so to speak) would foul it from
descending too far (into the bottom bracket shell region).

Provision would have to be made, if there were any expectation
of multiple riders requiring different-height seat posts.

If the semi-permanent s.p. section tended to fall out
(upwards, towards the seat tube opening) during folding
or storage, provision would need to be made for that
event (I'm thinking: just pay attention, in those circumstances,
and avoid being surprised by the loose section).

Seems to me this Papillon approach has merit.

Ya gotta have a plan.

I haven't had a single chain drop on my Xootr Swift.

I run an 8-speed (11t-34t) Shimano cassette, but I have detuned the
SRAM X.7 rear derailer H-Limit screw, to avoid the 11t cog entirely.

This makes the bike a 7-speed, if taken alone. However ...

Using only my behavior, I also avoid the 13t cog, when riding on
the inner chainring. Taken together, this gives 6 speeds, and a
more narrow chainline variance (less of a steep angle from
chainring to cog).

To pick up groundspeed, I have a 48t outer, in addition to the 40t
inner chainring. There is, however, no front derailer. I dismount,
to change gear ranges. If I don't miss, I'm back on the bike, and
riding the other chainring, about ten seconds after I'd dismounted.

. . .

The matching SRAM X.4 trigger shifter is an 8-speed shifter. Since
8th gear isn't reachable, the shift cable simply goes a bit slack if I
make the attempt -- and the bike remains in 7th gear.

The SRAM unit is a short-cage derailer, X.7, which I find reliable
and precise. I had the notion it would not take as many road dings
as a medium-cage derailer would have. Time will tell. Perhaps
it contributes to chain retention, somewhat.

The derailer cage tensioning spring of the X.7 is impressive, and
provides some needed chain discipline.

Capacity is limited! I think there's around 30t of capacity in this
derailer; I don't recall at the moment. Part of the reasoning behind
obstruction of 8th gear (11t cog) access was to narrow the capacity
a bit.

The chain is short enough that the derailer cage (and chain) does
not double back on itself (to excess) when in a slack combination
(small-small -- 40t, 13t) and long enough not to rip apart the derailer,
when accessing the large-large combination (48t, 34t).

The driving factor, in selecting transmission components, was
the short-cage derailer, for its height above the pavement
(relatively higher than a long-cage derailer) when installed.

> On another topic, where is a rear battery-powered light
> best positioned?

I'm running a rear, bolt-on rack, and the light goes at the
back of it, as usual. That keeps it clear of any luggage
mounted on it.

Makes it a lot easier to lift the bike (as an alternative
to lifting the bike from the seatstay) while doing light
maintenance. Heel strike is a problem with any luggage
(even the rack-top bag I have offers some heel strike,
I think).

Are not the seat posts 34 mm as stated on the Xootr site? I really don't need to fold my Swift and have opted to replace the QRs withAallen bolts and Nylok nuts, after greasing the seat post well. Will this cause my frame to crack? My thought was that the flexing of the post from being loosened and tightened is what would cause failure.

This makes sense for setting the seat height easily. But it only obstructs the seat pin from moving downwards through the bottom QR. If the QRs aren't tight enough to hold the seat pin, it can still move up through the bottom QR then down again, and up or down through the top QR as the bike flexes. This chatter could fret the frame or seat pin.

That's an interesting fact. I've just measured my seat pin, and it yo-yos from 34.05 to 33.79mm, depending on where it is measured. I hope it isn't wear.

As a complete aside, I've just folded my bike thus: front wheel rotates ~170deg to the left hand side, then seatpin is raised and rear wheel rotates under the bike. Front wheel passes between rear wheel and kick stand, so it can't rotate. Seatpin goes down and is clamped. The whole unit is then becomes quite a stable package and can be lifted by one hand and shaken around without the front wheel swinging.
For those having custom frames made in the future, a 1" spigot welded somewhere would enable the handlepost to be stowed securely, too, using its own clamp. Underneath and to the front of the top tube might be one place, but you might think of other places that would be better.

I tried replacing the Q/Rs some time ago and used Allen Keys instead. Be careful not to over tighten the bolts. I slightly over did the bolts and managed to squeeze the frame slightly making the seat post a very tight fit and not easy to slide for folding. I've checked the frame under a magnifying glass for possible damage but it appears to be OK and over time, the post has become easier to move without being a loose fit.

Jur did something like this on one of his bikes I think. He was making it lighter. Machined the regular seatpost to accept another seatpost inside it. It is pictured on his web site---it is awesome.

OK Pebc.. I think you are getting confused between seatpost and the QRs. The diameter of the seatpost is 33.9/34.0. There is more stress on the Swift seatpost than most bikes because of it's length and because of it's double function. The quick releases (qr's) that come with the swift are very inexpensive models (and low quality in my opinion). As long as you get better quality qr's that fit properly you will be fine. ps---I owned and managed a bicycle shop for 30+ years... I have replaced a lot of qr's in my career on different bikes.

Most bicycles do not have built in seatpost clamps like the Swift does. They are usually an additional piece that slides down onto the bike seat tube. This would be hard to do on the swift with the double function. Lifetime warranty on the frame helps eliminate my fear of failure.

Did I mention I love my Swift....

Thought I'd share this. Just upgraded the drivetrain with an 11-36 cassette and a SRAM Rival 1 RD. I'll use a Sugino 53T chainring for now and see how it goes; if I start dropping the chain, I might upgrade to a Wolf Tooth narrow wide chainring. I didn't really have problems before, but I'll see.

They certainly are a good looking bike.

[MENTION=388660]Vanrex[/MENTION], can you tell me how you got the canti-posts removed and what calipers you're using?

I bought the bike this way from Peter Reich at Design Mobility last year. He cut them off a stock frame and smoothed them out for me, probably with a grinder or dremel tool. It's not perfect; if I look closely, I can see where the posts were. But it's still pretty good.

The brakes are Tektro 559's. I had to replace the stock pads because they barely slowed the bike. After I put Kool Stops on, I almost went over the handlebars testing them out, they're that much better.

Let me know if you'd like the rest of the parts list.

Assume he painted the frame after removing the posts?

Yes, yes he did.

It looks great. Much cleaner than posts with calipers.

I would appreciate knowing the rest of the parts list for the brake upgrade.
Thanks
PCG

Wow!!! The black frame version is super gorgeous!!!

No problem, the brakes parts list is:

- Tektro R559 long reach callipers with Kool Stop salmon pads
- Jagwire brake cable
- SRAM Apex right brifter (2015 version)
- SRAM S500 left brake lever (cosmetic match to the brifter)

To use caliper brakes, I needed to spec 451 wheels, so I've got Sun CR18 rims and Shimano 105 (5800) hubs. I ended up putting on Panaracer Minit Lite PT (28-451) tires.

Other bits and pieces are:

- Nitto M176 Dream (44 cm) handlebar with Nitto bar end plugs
- Nitto UI-85GX (90 mm) stem
- Sugino RD2 (170 mm) crankset
- Sugino 53T chainring
- SRAM Rival 1 medium cage RD
- SRAM PG1050 11-36 10-speed cassette with Shimano Tiagra chain
- Shimano UN55 (110 mm) bottom bracket
- MKS Touring Lite pedals
- Specialized Phenom saddle
- Specialized Roubaix bar tape

Everything else is stock, included the QRs and the head set.

Hope this helps.

So the reason you went with 451's was because you wanted calipers? That's interesting. I assumed it was the other way around.

I think he wanted Brifters which don't work on V-brakes but work on Calipers. If you were to put calipers on with the 406 wheels the arms are so long they would barely slow you down.

Most of the folding bikes (Swift, Dahon, Tern) are designed to work with both 406 rims with V-brakes and 451 rims with Road Caliper brakes.

While that's true, cantilevers work with brifters and 406 wheels, which is why I assumed he decided he wanted the 451's first. I'm currently debating the 451/caliper vs. 406/cantilever alternatives myself and the wheel size seems to me to be a more important choice than the type of brake.

It all started with me wanting a drop bar. When I started looking at the different brake levers available, I thought about using barcons/Tektro RL520 levers with V-brakes, but thought it would be cleaner to use a brifter. After that, I thought about using either cantis or V-brakes with travel agents. I didn't want the possibility of heel strikes, so I ruled out cantis. And when I read about some people's experience with travel agents, they left me underwhelmed; plus, I thought it would be cleaner without them. Mini-V's sounded like they could be problematic, too. So, that left caliper brakes, which required the 451s. Because I was starting from a clean slate, it wasn't a big deal.

I ended up putting Tektro RL520s on another bike, and find they're less comfortable than the SRAM levers. But that's just me.

A pain I've found with the 451s is tire and rim selection, but I've been able to make do. But they do make the gearing slightly better.