29er tube in coker help

I’m going to try the 29" tube in my Coker thing, and see what happens. But I went to the bike store today, and they have a ton of different 700c x ##, and I know that one of those is the right 29er tube, but I don’t even know what those numbers mean, so I didn’t know which one to buy.
so, in 700c speak, what is a 29" tube?

Tire sizing article

Specific 29er tube installation instructions

okay, soo…700c means that the tire is 700mm in diameter, and the second one is how wide the tire is in mm, right? hrmm, I might be missing somethin here, but I’m still not completely sure which one the 29" is. well, I figured out that 700mm = about 27", so I guess something wider like a 700c x 50 would be about 29 inches, right?

U-Turn’s link to the 29er tube installation instructions is bad. The forum software is messing up the URL because of the spaces or other odd characters in the URL. Here’s a clickable link using TinyURL:
Installing a 29er tube in the LiveWire 36" Wheel

I just ordered some Schwalbe 29er tubes (Schwalbe calls them 28" tubes) to try in my Coker. I haven’t gotten around to trying them yet because I got distracted by my broken Coker hub. U-Turn has a link to the Schwalbe North America web page where you can buy the tubes directly from Schwalbe. Minimum order is $15 which means a minimum of 3 tubes. The tubes ship from Victoria BC Canada which is handy since I live in Washington.

I was surprised at how difficult it was to buy a proper 29er tube. Most bike shops don’t stock that size of tube. A lot of the online bike shops also don’t stock that size of tube. And if you’re looking for a tube with a Schrader valve for the Coker wheel your choices get really limited. The Schwalbe tube was the best option I could find. You can either order directly from Schwalbe or go to your favorite local bike shop and have them special order the tube.

It probably would benefit you to take quite a bit of time with the article, since it is a confusing subject, though I think Sheldon Brown does a great job with it.

“700mm” is nothing.

“700 C” is a French size. It refers to a Bead Seat Diameter (BSD) of 622mm. It has nothing to do with tire width. The ISO term for this size is 622mm.

“29” is a rough inflated-tire-on-wheel diameter. For example, the Schwalbe Big Apple 29x2.35 tire on a Rhyno Lite 700c rim has:

– A BSD of 622mm (this is fixed with a wire in the bead)
– An inflated tire diameter of about 30" (as measured by me)
– An inflated tire width of about 60mm = 2 24/64" = 2 3/8" = 2.375" (as measured by me)

The Schwalbe tube AV19 is listed as 40/60-622/635, which means that the company certifies it as being suitable for tires from 40mm to 60mm wide, with BSDs from 622mm to 635mm. In practice, of course, the tube will stretch more than that, which is why we can get away with it. :smiley:

Ah thanks, John for the link fix.

You can buy the tubes from LiveWire too =)

I forgot to add that U-Turn’s web page on installing a 29er tube in a Coker includes a link to the Schwalbe North America web page where you can order the tube. AV 19 is the size that you want. AV is Schrader valve and 19 is the number for their 29er size (40/60-622/635). 622 is the rim diameter for a 700c rim and the 40/60 is the width.

hmm, okay, I think I do understand it now…yeah, it does seem like a pretty confusing topic q-: I think I’ll prolly order the Schwalbe tube John recommended…

Bontrager also make a 29" inner with a Schrader valve. I don’t know where you can get them from, though. (They aren’t available in NZ, anyways.)

Bontrager is owned by Trek now so I would guess that a bike shop that carries Trek bikes would be able to get the Bontrager 29er tube.

I didn’t know Bontrager made a 29er tube, and especially one with a Schrader valve. I went to one of the local Trek bike dealers asking about 29er tubes and they were clueless. I guess they didn’t realize Bontrager made them. Shopping around for a 29er tube can be an exercise in frustration. So many shops know nothing about 29ers.

Bike shops are useless for 29er parts.

Schwalbe do 700c 40-60mm, which is a really nice big tube.

IRC do a 29er tube, but I think in presta only. You could probably use it with washers, but it’d be a bit risky as they’re not such sturdy valves.


aaalright everybody. I did it.
bought the 29er tube, and stuck it in my Coker, but thus far haven’t had much of a chance to try it out yet. I have tried it out, and it’s AWESOME!! it turns so easily, and speeds up/slows down so easily…sweet.
but. for some reason, my rim now seems waaay out of true, vertically. as in I can feel it going up and down when I ride, and of course I can see it when I get off and spin the wheel.
is it possible that I bent the rim while pulling on it to get the tube on, and the tire on/off, etc.?

also. I was wondering, has anyone seemingly successfully install a 29er tube and ridden it for a short while, then have it pop while they’re on it? because that would suck. a lot. so I’m just wondering if that’s something I should worry about.

Your tire is probably not seated correctly in the rim. The bead of the tire needs to fit evenly all the way around the rim and on both sides of the rim. If the bead is not properly seated the tire can have a bump (almost like a flat spot) just like you describe.

Deflate the tire and then reinflate it to about 50 psi or so. Then let it sit for a bit. The tire will try to even out the pressure on it and will try to even out the bead all the way around. If that doesn’t work then deflate and try again. If that doesn’t work then get forceful with tire leves to even out the tire.

What I do now for the Coker is spray the bead of the tire and a bit of the sidewall with Silicone spray lubricant. That seems to help with installing the tire and also helps the tire to seat itself after being inflated.

Do you have the stock rim or Airfoil?

Also be careful with the rim strip or rim tape. It is very easy to peel away part of the rim tape and expose a few spoke holes while trying to install the tire. This is especially true with the Airfoil rim. After getting the tire installed, and before inflating it for the first time, you should stick a tire lever down the side of the tire and inspect the rim tape all the way around the tire and on both sides of the tire. Make sure the rim tape hasn’t folded over in any places or shifted over a bit. Make sure all the spoke holes are still covered. Every time I put a Coker tire on an Airfoil rim I have to make adjustments to the rim tape after the tire is installed.

I just helped tomblackwood put a 29er tube in his Airfoil Coker last night. Wasn’t too difficult at all. In fact it was one of the easiest tire installs I’ve done with the Airfoil rim. It was also the second time that I did the silicone spray treatment. Seemed to help a lot.

Yes, it is true. The Doctor made a house call. I tried to “help”, but in the end was extraneous. The rim-fighting challenge JC was hoping for just didn’t materialize. That aside, I learned a ton in the process, and as always JC rocks!

I should also note that this was my first tire change since purchasing my GB4 36 from U-Turn, and it happened at exactly 1,300 miles. The tire was bald but not quite down to the threads. In addition to a new Coker tire, I dumped the heavy Coker tube for a lighter Schwalbe 28" tube. After a 10 mile ride tonight, I have to say that the difference is dramatic. Felt squirrely at first, but almost everything is easier with the 28" tube. Mounting, idling, stopping, starting after a standing break, accelerating, and especially CLIMBING. Stuff I had to stand up for yesterday I stayed in the seat for today. Only areas it was tougher was gravel (marginally), sloped crowns, and steep decents with brake. On the downhills, a light feather touch on the Maguras was definitely more critical…less mass in the wheel to help roll it through the braking.


U-turn’s 29" installation instructions are great. Thank you for the help.

One suggestion for a one person installation, at step 5):
Tie the tire/tube/rim points at two anchor points (~180 degrees apart) to hold tube in place and continue to stretch the tube completely around the rim.

I wrapped short bungee cords around to anchor/hold things and then completing the tube stretch was easy.

(My mounting the second bead of the tire is another ongoing story.)

I just recently did my first Coker tire with 29er tube installation onto an Airfoil rim. I was going to resurrect this thread but then this thread was resurrected and now this one.

I got my Airfoil rim, TM Spokes, Sem nipples and UDC wide hub a while back. unisk8r laced it up and trued the wheelset. He sold me one of his Bontrager 27 x 1 3/8-1 3/4 / 700 x 35c-44c tubes that he uses in his wheels.

Pete suggested inflating the tube to pre-stretch it and then deflate it onto the rim. After doing that I placed the rim with tube inside the tire and worked the first bead on by hand. On the second side I experienced the same problem many described about that last 18”. Of course I didn’t search the for a before attempting installation, I finally ended up holding one of the tire levers down with my foot (rather than the rubber band method which would have been much smarter) and worked the other side of the bead with the other two levers, about an inch at at time. These were standard plastic tire levers and worked fine. After the tire was on I inflated it by floor pump to about 35 PSI but the bead wouldn’t seat. I got tired of the floor pump and resorted to the air compressor; it seated after a while at about 40 PSI.

The next problem I had was that the tire was down to about 20 PSI the next morning. I deflated the tire, checked for pinches, and re-inflated. After a day it was down to 20 PSI again. Looks like a slow leak that “seals” at 20 PSI. Rather than go through the hassle of another dismount & mount of the tire I thought to try some tire sealant. I didn’t realize they recommended 4-6 oz. for a tire the size of a Coker. There goes your weight savings. Instead I put only about 1-2 oz. in and spun the wheel for about ½ hour this morning (to kill time I read the paper and lurked on RSU). I pumped it up to 40 PSI and left for the Thanksgiving gluttony. Came home this evening and still at 40 PSI.

Now I can hardly wait for the frame to show up so I can ride the new wheel.

No tools Coker still applies (except for the choice of rim tape)… just did one a couple of days ago with a 29er tube. I’m not a he-man-type, so you guys with V-shapes and actual abs shouldn’t be having these troubles. Take your time and keep pushing the bead into the center channel.

Having failed my previous attempt with mounting 29 tube on my Coker, I’m getting the urge to try again. (I had the tube in, but could not get the tire on. LBS then mounted the tire with the original full size tube.)

Is there a difference between mounting a ‘Coker’ or a ‘TA’ tire on the airfoil rim. I know they both can be hard to mount but could it be that the TA tire (like I have) is more difficult to mount than the Coker tire?

Well, I just trashed all three of my 29" tubes (Schwalbe AV19, three more on the way) and I’m working with a Coker tire. I don’t know if the TA is harder, but the Coker sure isn’t easy. I don’t know how to be sure the lever isn’t pinching the tube once there isn’t room to get my fingers in there.

I’m not looking forward to getting a flat and having to do all this again, but I sure would like a lighter wheel for the Laos tour.

Now I’ve done a few 29er installs, mostly successful, and I have to say that doing it no-tools is really difficult and probably not worth the trouble.

I assume you are talking about the 2nd side of the tire. In this case, use more air in the tube. This makes it harder for the lever to grab the tube and more likely for the lever to slip past the tube where it belongs. It also makes it harder to get the tire into the center channel, but that’s a complication that we have to live with.

Scott Wallis also recommends talc all over the tube.