How do I install a 700mm tube on to a 36" Coker?

I have searched for an answer and gotten a couple of answers but I am blowing tubes and can’t figure out what I am doing wrong??

I blow up the tube for several hours so it will slide right over the big rim. I then put the Coker button tire on half way and put the tube in trying not to twist it. I blow it up slowly and it felt like one side is firmer that the other but I continue to blow it up to 40psi and I bounce the tire several times and I feel even pressure all the way around once it is full.
When I leave 30 minutes later the tire is still fully aired. Two hours later when I return it is flat. The tube blew out, it wasn’t a pinch flat or a hole. So now what am I missing, I really want to figure this out.

Thanks for any help you can provide.

What brand of tubes are you using? You pretty much need higher quality tubes for this since they are stretching so much more than they were meant to. I think I used a Cheng Shin tube. It worked very well with no punctures in a year and a half but most people seem to suggest the WTB tube. Either way get the widest one you can but not necessarily the thickest. It is important that they expand evenly especially if you plan on using moderately low pressures.

Also check your rim and tire for burrs that may be causing the flats. It might not be the tubes fault.

I am using Inline Boxed Tube 700 x 35/38C…I ordered 5 of them? I also tried a walmart bell brand of 700 38/46c and it did the same.

I hope I can use these Inlines.

I would try a 29’er tube. something along the lines of 700x50c, or bigger if you can find it. I have a tube that is 29x2.1-2.4, I think it would be in the ballpark of what you are looking for. My tube is something like this. If you look at the spec’s it says 700x48c-58c, and I think mine is 50c-60c.

The size you are using is what I have in my cyclocross bike, and I would be leery of using it in even my 29’er uni much less in a Coker. But if other people have got it working than it must be possible.

Thanks…I guess I will keep the smaller 700’s around for my road bike…but I already extras for that?? Man I hate waisting money.

I just added up what I have put into my 26" Sun that I got for $90…I have put $190 into it…but it is now all my parts except for the frame…and a fast 26" uni for sure.:smiley:

Has anyone used the “Qtubes” like jtrops linked to? They look good to me as long as they are a good quality tube.


Unless you specifically order a special purpose tube most of them are comparable. There are bad ones, but not really by brand. Qtubes is the QBS (Quality Bike Supply)house brand for tubes. They are most likely made by a variety of factories, and are pretty much average quality. They are probably good for what you want to do.

You could go to High Gear on Main Street and get tubes from them, or Blue Sky Cycles on Airport Road.

Inline makes a 29er tube that is much better for this. They are 700x54c, as opposed to the 700x34c tubes that you have. They cost about 3 bucks Canadian at MEC so my guess is they will be about the same at REI. They are in fact made by Kenda and not actually inline (nothing is actually made by inline).

The nice thing about these is that they have a schrader valve as well. The other brand that I have used is Bontrager tubes, I used one of their 29er presta valve and never had a flat until I tried to change the tire.