Tyre valves

[atreyu]

Can anyone give me abit of advise regarding tyre valves on cast wheels.

My old tyres when removed had tubes fitted front and back, I was told this is illegal? or certainly frowned upon.

My question is where can I get the correct size valves. I really want the modern metal 90 degree angled type. The holes in the wheels measure 10mm (front) and 8.7mm (rear). I've found 8.3mm valves which I presume are correct for the rear, but I cant find anything suitable for the front. They seem to jump from 8.3mm to 11.3?

[russell allen]

Some cast wheels are designed for tubes especially from the late 70's early 80's. Several bikes I have owned are like this Yam LC350, Moto Guzzi V50, and almost certainly all cast wheeled morinis. It is not illegal to put a tube in a tyre on a proper tubeless rim.

Russell

[mgill]

My BMW with "snowflake" mags require a tube as well...
find a better tire shop.

[morini500dave]

Hi
The Morini grimeca cast wheels are not designed to use tubeless tyres ie any tyre without a tube,if it's a case of finding a right angled valve then angled adapters are available cheaply on e-bay,I recently bought a pair for a very reasonable £4.20 including free P&P.
Hope this helps.
Dave.

[morini500dave]

Hi again
The adapters I bought on e-bay are item number 350412426876,I use them only when I need to add air to the tyres,not keeping them on as they may cause the wheel(s)
to become out of balance at higher speeds?

Dave.

[atreyu]

Thanks for all the replys.... Short of a VFR400 this is the only bike I've got/had with cast wheels! Bought tubes so will drop the wheels off at a local tyre place rather than my local bike shop. Would put them on myself but I dont trust myself marking the shiney wheels!!

[Morizzi]

Whilst all the above about cast wheels being either designed for tubeless or not is true I have found that a lot of cast Italian rims of that era seem to cope tubeless as long as the valve aperture is reemed to suit a tubeless valve stem.

There is hot debate on some forums as to if you should or shouldn't. I really don't care but found that after buying a couple of second hand Italian bikes I had been running on tubeless without even realising it. The issue is that the rim doesn't have the safety bead that tubeless tyres should have. I only realised after getting a puncture. At no stage did the tyre ever come away from the rim and a bead breaker was always needed.

The advantages of tubed tyres is that they don't tend to blow out but go flat slowly. A small plug kit and inflation device can get you going without too much hassle.

Up to you.

Cheers

Rod

[EVguru]

Putting a tube into a tubeless tyre generates more heat, so the speed/load rating is reduced. Many tyre manufacturers have information on how much reduction is recommended. With Roadrunners being rated to 130mph a bit of de-rating is not really a problem.

Running tyres tubeless on rims not designed for it is not a good idea. Your insurance would be invalidated and you'd leave yourself open to prosecution if the state of your tyres was in any way implicated in a crash. It's possible, but the safety bead was introduced for good reason. There are rim converters available, essentially a very low profile tyre that fits into the well and keeps the beads seated. They're generally used to convert spoked wheels.