Questions with 28" tube on a 36" wheel


Due to the batch of X airfoil rims I decided to make a coker from a friend wheel. So I bought his old steel coker rim and one of his coker tire. I also bought a frame, 127mm cranks, a suzue hub and a 28" tube from Bedford ( Darren did not have 36" tube in stock ). The pedals, seat and seatpost I took them from my trial uni.

I put the tube on the rim and had not a lot of problem ( I made a little hole while streching the tube that I fixed with glue and a patch ). Everything look okai so I went for a little ride to see how it goes.

After a few meters, I noticed that there was bump at each revolution so I looked at the tire and see that there was about a section on the tire that has less air pression. I dont know how it is possible. :frowning:

Is there a way I could fix this problem?
Should I just ride until it popped and then get a 36" tube?
Anybody had a similar problem?

Sorry if you had problems to understand my english

Thank you

36" tube?

I will buy a 36" tube one day but I need to order one from which I dont like to do because it’s in the USA and it will take a long time for me to get it. So I’m looking for a quick solution

I don’t believe it is possible to properly patch a 28" or 29er tube for a Coker wheel. The problem is that the tube needs to stretch a lot in order to fit the Coker tire. The patch will not stretch the same as the rest of the tube so you’ll end up with a dimple area in the tube where the patch is. You’ll feel that dimple or blip in the tire as you ride.

Best bet is to use a new unpatched tube. Use the old patched tube in a 29er or give it to someone who has a 29er. The patched tube is no good for a Coker any more.

On that note, is there any advice on using a 28" tube on a coker wheelset?

Dave Stockton has a guide on installing a 29er tube in a Coker.

It works. It’s lighter than a Coker tube. But the tube is also overstretched and thinner and more vulnerable to flats.

I’ve been running a patched 28" tube in my 36er for about a year. The patch hasn’t failed yet. Use Dave Stockton’s installation guide.

What type of patch did you use?

Based on how much a 29er tube has to expand to fit the Coker wheel, I have a hard time believing that the patched area will expand correctly to fill up the tire. Maybe the patch will work better if the tube has been used in the Coker tire for a while and is already pre-stretched.

Great tutorial, thanks for the link!

Thanks guys for the advice. It was really helpful.

It’s from a patch kit I found in the Walmart automotive department. I think it’s actually a tire patch, not a tube patch. Works well though.

Looks like that.

That’s a regular tube patch. Rubber cement and a rubber patch with feathered edges.

There’s also glueless patches for bike tubes. I was curious if you had used one of those. They usually don’t work well.

I don’t remember if I did this or not, but I bet if you patched the tube while it was wrapped around the rim you wouldn’t have to worry about it stretching too much more.

I ran a patched 29er innertube in a coker wheel for about 4 months without any problems, and no irregularities/lumps. When it finaly gave way I have a feeling it was because it sat for too long underinflated, and instead of being squeezed between the tire and tube it was just hanging onto the tube and fell off.

In any case, it was a park glueless patch kit, and I patched it again though when it only lasted a month I decided to get another tube.

As far as tubes, I’ve had good luck with Quality tubes (just about any bike store should be able to get them, though I have a feeling they may just be rebadged Kenda tubes…), only time I got a flat was from slamming into a set of steps. I suppose for that matter two tubes isn’t a good sampling rate though, perhaps it’s best to just call it luck and not try to infer the quality of Quality tubes.