Tubeless MTB rims

[timbo]

Can someone please explain tubeless MTB rims. I'm familiar with tubeless road rims (but don't have any), but the MTB rims look just like normal tubed (clincher) rims. What are the differences and what are the main advantages Thanks.

[Andrew69]

I think the only real difference is that the tubless rims are double walled so the spoke nipples are sealed off from the tyre.
Main advantages would be no more pinched tubes at low pressures and slightly reduced weight

[MountGower]

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[Kalgrm]

The main advantages are:

• * Lower pressure -> better traction and reduced off-road rolling resistance
  * No pinch flats
  * No flats at all if you run sealant too (well, nearly no flats - you can still pull the bead off the rim and flat. Bugger!)
  * Reduced rolling resistance because no friction between tube and tyre walls
  * Reduced weight without a tube, but somewhat negated by the use of sealant (optional but recommended) and the fact that UST tyres have thicker side walls.

The main disadvantages are:

• * Reduced selection of tyres
  * Flats are a pain in the backside to fix without a high-flow compressor. CO2 is good, but if you miss sealing the bead, it's a long walk back. Carry a tube for this possibility.
  * Lower pressure can pop the bead when cornering
  * True tubeless requires special rims, however you can convert any rim using Stans No Tubes (link here)
  * Sealant (if used) can be messy and difficult to get a good seal with. Used with the wrong tyres, it can cause the walls to delaminate, ruining the tyre.

To go with the Stans No Tubes web site, there is a another great web site which is a piss-take called "Oliver's Yes Tubes". Always good to link to when the debate over tubeless gets out of hand ......

Cheers,
Graeme