Tubeless Rim's in Twinshock class

[leeross]

Are you allowed to use tubeless rear rim/tyre in twinshock events?

ive looked on the ACU handbook but cant see anything in there.

Is it worth the money/effort to respoke the rear to run a tubeless rim/tyre?

[woody]

There is no such rule and I can think of no logical reason why one should ever be introduced (too late anyway as a lot of bikes have them fitted)

I've changed some of my bikes to tubeless over the last few years, mainly because of the eratic quality of the tube type IRC rear tyre. Some have very soft sidewalls which can make the bike very difficult to control on rocks or cambers due to tyre roll. Others seem to be fine but can (not always) soften eventually, particularly with spirited road use... Also, the softer the sidewall the more chance of compression punctures. The only other tube type tyre is the Michelin radial which is different from an X11 and is utter rubbish in mud. May as well use a Michelin Pilot. Probably ok on rocks but mine wasn't on long enough to find out.

Tubeless tyres will sit ok on Akront tube type rims with a tube fitted, but not always Takasago or DID. They pop out ok when first inflated but as soon as they are let down to about 10psi part of the sidewall drops into the rim and nothing seems to stop it, even leaving it for a couple of weeks with 90psi in it. So it's possible to use a tubless tyre on a normal tubed rim in some cases.

An alternative is the Tubliss system, see link below. This effectively converts a tube type rim into a tubeless arrangement. My KT250 rim won't hold a tubeless tyre, it drops into the rim, as above. With the tubliss system fitted it will hold an IRC tubeless tyre no problem. I've done about 6 events with it fitted no problem, running as low as 3psi. No tube type tyre roll and no compression punctures. Not too fiddly to fit and a good alternative until I can get another wheel to convert to a tubeless rim as ultimately, although the tubliss system works well, that's my preference.

http://www.tubliss.co.uk/

As to whether it is worth the cost of converting to a tubless rim, there is no real benefit in terms of grip, an IRC tube type will grip just as well as the tubeless version (assuming it isn't the roly poly type in which case higher pressure is needed to stop the roll which reduces grip) Tubeless also reduces the possibility of punctures as you can't get a compression puncture to a tube. So in my opinion, for that reason alone, the tubeless is a better option ultimately, but it is just my opinion.

[furse]

Do you use a tubeless tyre or tubed tyre with the tubliss?

[woody]

Do you use a tubeless tyre or tubed tyre with the tubliss?

I've used a tubless tyre, can't see what difference it would make using a tube type though.

[grib]

On a similar note; will a tube type front tyre sit OK on a tubeless rim (with a tube in it)? I have just bought a Fantic 245 and it has a tubeless front rim but after having read that tubeless front tyres aren't very good I want to use a tube type.