alo

Where I am in S E Asia the cheapest parts are available. So you get the thinnest tubes. Thin tubes are more likely to become unreparable when they do get damaged. Maybe you can get thicker ones somewhere. You would need to look in a lot of shops, and you may or may not find them. So I decided to try motorbike tubes, which are thicker and stronger than bicycle tubes.

My wheels are 26 inch. The tube is 21 inch. Some of you may think they wont fit. I found out they do. It seems, 26 inch tires originated with a 26 inch outside diameter, not the diameter of the rim. With 21 inch motorbike wheels, it is the diameter of the rim.

My 26 inch tires fit a 559 mm rim, which is 22 inches. A 21 inch rim is 533 mm.

So the 26 inch bicycle rim size is one inch or 26 mm larger in diameter than a 21 inch motorbike rim. Less than 5% larger. It is near enough for the tube to fit.

I am actually running a 2.75/3.00-21 tube in my 26x4.0 fat bike, so it is stretched more than it was designed for, but I think it is still stronger than a thin 26 inch fat bike tube. If I come across larger motorbike tubes in the future, I would buy them.

The motorbike tubes are heavier, and some of you wont like that. I prefer toughness than light weight.

I will also see how I feel after using these tubes for a couple of years. Sometimes unforeseen things become apparent when you experiment with something new.

indyfabz

Personally, I don’t care what you do. You do you.

/thread

shelbyfv

Yes, please report back then.

Troul 

will be gooders to use on rough roads at night. If you don't already have a light, you may find that the motobike's headlight are far larger to illuminate far. Easily to mount & to power it, any battery shop could set you up with a rechargeable Li-ion. Stators are usually integrated with the engine, but you could find an alternator & pdm to do the job. grab an idler setup so you can retain a serpentine belt.... v belts are old tech.

alo

There is no noticeable difference between the bicycle tube and the motorbike tube, when riding. It is a thicker tube, but it is stretched further, so in the end it is not that much thicker.

I also run my tires at higher pressure than some others. I am heavier than many of these people. I have found that running fat tires at low pressure requires more effort to pedal. I like to make it easy. The maximum give would probably be only one inch (25 mm) if I hit a large bump hard. With normal riding, there is less give.

alo

I did do one thing differently when fitting the motorbike tube. The valve stem has two nuts on it, one for inside the rim, and one for outside the rim. On a many motorbike rims, the middle of the rim is a bit deeper than the edges, and this nut sits down in the low part. My fat bicycle rim is flat across the middle, which would result in a gap between the tube and rim around the valve stem. Because I am overstretching the tube, this may be a problem. So I cut two rubber circles from an old truck tube, and put them around the nut on the valve stem. One is larger than the other. This results in the tube inflating against this rubber, eliminating a gap. I also put another one around the valve stem after fitting the tube, so the nut doesn't scratch the rim.

Peruano

Good thinking under the prompting of necessity. Thanks for sharing your experience.

livedarklions

Is that really necessary? Don't click on the thread then. I find this experimentation out of necessity interesting, but I don't think anyone else should care whether you or I want to engage in the thread.

indyfabz

I was responding to at least one sentence that appears to have since been deleted from the OP. The edit note doesn’t always show up. I’ve edited posts where it hasn’t. This post was edited twice.

livedarklions

That must have been one hell of a sentence.