weird riding Coker with 29' tube

Has anyone else had this problem?
I finally got a 29’ tube inside my Coker after 2 blow-outs and puncturing the tube twice while putting the wheel. :frowning:
I got to say, it was a real bitch to get this 29’ tube in a Coker! :angry:
I had no choice but to use the 29’ tube cause no local bike shops had 36’ tubes and I did not want to wait days for an order. I have to ride my uni, NOW DAMN IT!!

Now, I digress.
Any Cokeurs looking to put a 29’ tube in a Coker: the trick is to INFLATE the tube BEFORE putting the wheel back on and DO NOT USE air compressor to inflate the tube!
Now I am riding around on my Coker with the 29’ tube and when I zig-zag around, it feels as the wheel seems to “shift” out of place, sometimes. I keep thinking the wheel is coming off due to the smaller tube but when I stop to check everthing looks okay!
The Coker does feel lighter and faster; but I am nervous that my wheel will pop loose while I do a hard turn.
I have about 40psi now, maybe I should put more pressure.
Any ideas?

Heh, I’m waiting for my LBS to get the 29er tubes I ordered from them so I can attempt to mount it in my Coker. I already shredded one tube in the effort. Hope I do better on these (I ordered three tubes in anticipation of a difficult mount). I’ll post a writeup once I’ve gotten a chance to ride my beast.


Re: weird riding Coker with 29’ tube

I don’t understand. Do you mean inflating tube before forcing it on the rim? Won’t that make it even harder?

Stupid question:

Where does one get a 29" tube? Are we talking road bike tubes, 700c fat tubes, or what? What size 29" tube (as listed on the box) is recommended for Cokers?

Couple of days ago I tried with a 28 x 2.35 from Schwalbe (their biggest). It was not difficult to get the tube around the airfoil rim. But it was awful getting the tire on the rim with the tube inside.

When it was done I inflated the tyre and there was two ‘pschhhhhh’ - one from ingoing air and one from outgoing air. I later discovered two small punctures which I am sure I created while wrestling the tyre with the tyre levers.

I am going to try again. My Coker upgrade (new hub & rim) made Cokering a lot more fun and if I can save 200 grams on the wheel it will be worth risking another tube. But the work man, the work …

I have some of these available, but (caveat) I haven’t been able (yet) to try this.

The tubes I use are Summit (made by Kenda) 700x50c. They also say on them 29x1.9-2.3. I recommend you don’t use anything smaller. The way to put it on as leadpan says is to do it in this order:

  1. Stretch tube over rim (not hard)
  2. CAREFULLY put tire in one side of the rim
  3. Inflate tube
  4. VERY CAREFULLY put the other side of the tire in the rim
  5. Inflate and enjoy.

One other trick you can try especially if you’re changing to a new tire or a tire that’s only been stretched on once is to do a practice run without a tube - get the tire all the way on. Then take it off and do it with a tube. I have put on a nearly new Coker tire onto an Airfoil rim with just finger power (once).

Finding these tubes may be difficult as most bike shops won’t stock something like that. My LBS ordered me some a nearby distributor and they arrived in 2 days - $4.99 each.

You will save 260g over the Coker tube and that is rotating mass out at the rim - very nice.

—Nathan who only had to puncture two tubes to learn this.

29’ in tube

I bought from a local bike store a 29’ WTB in my Coker. And the size is 700c x 13.8-2.125 with Presta valve. They seem to be plenty of 29’ tubes around for me to buy here at least. I would definitely NOT try 28’ tube on any Coker.
What nathen said is what I did.
One more advice, get someone to hold the tire while you try to insert the wheel in the rim with a plastic lever.
Or else you will pull you hair bald going in circles trying the get one side fitted while the other side comes off, I wasted 2 hours of frustration figuring this out…duh :roll_eyes:

Re: weird riding Coker with 29’ tube

Maybe try a 29 inch (") tube? Cramming 29 feet (') of tube into that tire sounds like a real chore!

On a slightly less sardonic note, are you using lots of talc powder on the tube?

Re: 29’ in tube

leadpan, a 28 x 2.35 tube is bigger than a 29 x 2.125 They are both made to fit the same 622 mm rim.

My latest attempt on putting small tube on big rim (this time a 47 x 622 tube) is about ten minutes old. I expect to hear a pop and a hiss any second.

I had to wrestle a lot to get the tyre on. I could not follow Nathans advice above because when mounting one side of the tyre it squeezed the tube so hard it was impossible to inflate. Instead I started the procedure by inflating the tube and then put the tyre on. But then the inflated tube prevented the tyre from getting down into the spoke heads groove. That’s why I had such a hard time. Hm, perhaps I could have let some air out …

When tyre was on I inflated to 70 psi in order for it to accommodate properly on the rim but it didn’t. Not even when I put almost 90 psi in it. So I mixed warm water with washing-up liquid and let it drip between tyre and rim where the bead did not fit. As soon as the liquid sunk in, the tyre slid in its place.

Just came back from the first ride with 29er tubes in our Hunter36s and IT IS SUCH AN INCREDIBLE DIFFERENCE!!! It’s like a new unicycle. SO much lighter and more responsive. We did about 25km of dirt (some of it very rough) on this ride and Beau picked up a thorn that just barely went through. It was a slow leak that we didn’t notice until we stopped for 45 minutes for lunch. Then the tire was mostly flat. Luckily, with tire irons and a patch kit and pump the repair took only a few minutes. I wonder if a Coker tube may have resisted the puncture? Who knows?

But I don’t think I’m ever going back to using Coker tubes. We were climbing previously unthinkable sections with ease. IT MAKES SUCH A DIFFERENCE!!! DO IT!

Is that clear?


Wait till you try my tubeless Coker Nathan!

Just another note- call me crazy, but I think I’ll be using 110mm cranks for the Alps. That’s how much difference a lightweight coker makes to your ride.

Seeyou soon!

Ken, you are a true wildman (I think I’ve said that before… and will say it again). We have been using 152s for the steep stuff and they feel short on steep descents. But I guess with the new wheels I finally don’t wish for anything longer even on 18+% grades. The tour doesn’t go above 11% often though… Maybe you’ll be stylin’ on 110s. Don’t worry, I’m bringing mine too!


Pretty darn clear. I have 1,183 miles on my current Coker tire, and it’s nearing retirement. When I change it for my new one, I’m going to try the 29" tube change as well. Only bummer with this is that I have two brand new Coker tubes in my garage, and zero brand new 29" tubes. If the 29-er works, I guess I can always use the Trading Post forum to try to peddle my Coker tubes to the non-believers.

As to the other “sub-thread”, today I cleaned the last “big steep climb” on 140s that I had previously only done on 150s or 170s. In the steepest sections–where I needed to get out of the seat–it was actually easier on the 140s. Not sure why that is, but I’m going to resist over-thinking it and just keep on training with the 140s.

Okay, I’m convinced now. Time to buy a 29" tube. Need to get an airfoil wheel also. And a new frame, been noticing the flex in it also. Why does all this stuff have to cost money? I thought one of the advantages to unicycling was the low cost. :smiley: Sometimes it’s hard to stay content in this country.

At least I’m satisfied with my seat and GB4 bars.


I was pretty curious about running a 29" tube after Nathan’s raving post. I took my first test ride tonight so I thought I’d give a report.

Bought a 29x2.35 Bontrager tube and proceeded to wrestle for about an hour and make 3 snake bite punctures with my big aluminum motorcycle tire levers. Decided technique needed some refinement.


Got pissed, bought 5 more 29er tubes (made by WTB this time).

Got smarter, bought four of these clamps after a tip from Surly Dave:

After fighting the loose rubber rim strip last night I replaced it with a proper Velox strip.

My process goes like this:

Get one side of the tire on, then stretch the un-inflated tube onto the rim.

Put the other side of the tire mostly on and inflate the tube to maybe 5 psi. This helps it get seated up in the tire.

Pull the 2nd side of the tire off and make sure the tube isn’t twisted anywhere (and mine was).

Put the 2nd side of the tire back on. The last 12" is a bit of a challenge. I used the tire clamps to make pinch the beads together on the far side of the rim, and hold it in the valley in the center of the rim. As I got closer to getting the lip on I used the clamps to hold everything in place (because I didn’t have any help).

I put a fair amount of TurtleWax “Wet and Black” on the bead surface to help it slip over the rim. Any slippery liquid would do this, but wet and black makes your tire look really nice! I’ve used it on my Jeep tires, a Gazz, and my 36" tire… all look great. It’d also probably help prevent a new 36" tire from cracking because it softens the rubber.

Once I got both tire walls mounted I realized I had some of the tube pinched under the bead. To remedy this I slowly inflated the tire and squirted wet and black on the offending tube. It took only a little air pressure and some massaging to get the tube to slip back into the tire.

Next I covered both tire beads with wet and black to help them seat as I pressurized the tire to 50 psi. Time to ride!

The Ride

Nathan wasn’t kidding… this is liking getting the turbo version of the 36". Acceleration and climbing are markedly improved. I’ve only got a few miles on, but I won’t be going back to a Coker tube (though I might carry one as my back up on rides).

Here’s a picture of my clamps and “wet and black”.


  • I think Grainger only sells to businesses, so you might have to find the same product somewhere else.

  • Because I managed to get this tube to work on the first try I have 4 extra WTB 29er tubes… I’d probably part with 2 of them if anyone needs some.

Wow, didn’t take you long to switch either George. I did a road ride 20 miles today with 125mm cranks and I am more sold than before. Descending is very cool. You might think that it would be more squirrelly, bouncy or somehow less control, but it’s the opposite. Smoother and faster. WOW!


Nathan, I’m also running 125 mm cranks… they’re great! I’ll probably swap them for something longer if I’m going to do anything west of Denver though.

Also, to clarify, I didnt’ have to use any tire levers with the installation techniques mentioned above.