Can you run a standard tyre on a tubeless rim?

Question

I have some new tubeless MTB rims and I'd like to avoid buying new tyres for them. The tyres are reasonably sturdy (Continental Race King Protection - 4 plies / total 240tpi) and I have sealant. As I understand it the sidewalls aren't as tough so you can't run on quite as low pressures as UST tyres but that's OK with me.

Any other potential problems?

Answer 1

I've never played with tubeless bike tires, but I assume there are conceptual similarities to tubeless auto tires. First off, a tubeless tire isn't really tubeless -- there is a "tube" (thin layer of solid rubber) laminated to the inside of the tire to contain the air. Presumably the sealant you have would serve the same purpose, but it's not clear how well.

Second, the tubeless tire has a specially-designed bead area, smoother than a tube-type tire and designed to seal tightly to the rim. Your typical bike tire has a fairly rough bead area, and not one that would naturally make a tight seal. But again, the sealant may make up for this to a degree.

As to the sidewalls, the likely problem would be that the tube-type tire's sidewalls are not flexible enough (and the bead not stiff enough), and so, when flexed, might not allow the bead to remain in tight contact with the rim. This could result in seal failures when hitting a bump, etc.

Answer 2

Yes, you surely can use standard tyres with tubeless rims. I do so and it's ok.

But you can expirience some problems (from my own experience and what I saw):

• As you already wrote, you cannot run on (very) low pressure;
• You can get a "snake bite" puncture relatively easy because of thin sidewalls (from my own experience - low pressure, hit a curbstone, get a puncture). However, the sealant solves this problem pretty good;
• If you turn fast enough at high speed on plain surface, tire can possibly slip off rim (seen that, never happened to myself);
• Standard tyre with any sealant looses air faster than UST. (Not a problem. Problem is that sometimes I forget to check for pressure before a ride.)

Relatively high pressure (30+ psi) fixes most of this potential problems. And full suspension bikes have less possibility to get a puncture if you are riding trails, forest, etc. So you get more advantages, than disadvantages, from using tubeless rims with standard tyres.

And it's still a good idea to have a spare tube and pump in your backpack, because you can get a bigger puncture or even cut and sealant will be useless.

Answer 3

Use Stans Notubes sealant and you should be fine.

Answer 4

Use tubeless or tubeless-ready tires. Racers often convert standard-tube-type tires to tubeless using sealant for an ultralight setup, but it's not always reliable. Expect more flats, trouble seating and sealing, and lots of trial and error with conversions.