10 replies to this topic

[lewis]

Right, small query to tickle the brain cells.

 

At current I am weighing up my options for wheels and tyres for my Hillclimb Mini I am building.

 

My question is this - are there any msa regulations against running inner tubes, and if not does anyone discourage the idea of using of them?

 

Thanks guys

[keefr22]

I'm guessing it may depend on what class you're building the car for. In road going production  or modprod you can only use List1A or B tyres (the latter depending on SR's or championship regs) - so that's basically road legal & trackday type tyres, while Libre can use racing tyres. I'm certainly no expert, but I'm pretty sure that my son's best mate who's a supervisor in Kwik Fit has told me that inner tubes can't be used in road tyres any longer? My mate hillclimbs a Libre Imp on slicks & wets & I don't think he uses inner tubes.

 

I'm wondering why you'd actually use them anyway, I only recall them being used for puncture repair or in historic type crossplies?

 

I can't find any specific mention of inner tubes in the Blue Book....

[Cooperman]

Inner tubes are not good in radial ply tyres due to the tyre wall flexure which chafes the tubes until they potentially fail. That is what I was told by a tyre engineer from Goodyear when I was rallying on their tyres.

[lewis]

Thanks for the response guys and sorry should of mentioned it will be mod prod class under 1400cc.

 

After what you have both said its probably best putting this option aside haha. I had looked at it for a couple possible sets of wheels that may require inner tubes, however safety first... last thing I would want is an inevitable failure at some point  .

[Ivor Badger]

Inner tubes are not good in radial ply tyres due to the tyre wall flexure which chafes the tubes until they potentially fail. That is what I was told by a tyre engineer from Goodyear when I was rallying on their tyres.

 

At one time they used to supply cross ply or radial tubes. Eventually they just supplied radial tubes. Tubes used to be compulsory for events on unsealed surfaces. The idea that the tyre could be pulled off the rim, deflate and the rim would dig in and the car roll. That idea went out the window after a mid 70s RAC rally when Dunlop complained that most of their punctures were caused by the dirt that got trapped between tyre and tube when fitting new tyres to used rims in the rush of service areas. The tyres were designed to be run tubeless by then anyway. Most race tyres by the late 60s were tubeless as with low profile tyres it was impossible to make a tube to fit. Think the left over tyre is now the 5.00Lx10 CR65, which was tubed when first made. Haven't been involved in their use for years and they are probably tubed now. CR81s were made tubeless.

[lewis]

Thanks for that Insight Ivor Its nice to know a bit of motorsports past.

 

All these issues surely begs the question, how safe are inner tubes on the road with road tyres today? Alot of people are looking down the converted split rim option that needs an inner tube to run so its going to be more popular. 

[Ivor Badger]

Why would you require tubes in split rims? The ones I have dealt with have O ring seals.

 

The reason for using split rims, ie width, surely prevents the use of tubes as the tyre profile doesn't allow the tube to inflate correctly.

[acrowot]

i use tubes on my race car and never had any problems i only use them because i only run 6 pound preasure in the front

[lewis]

Ivor I am gesturing more toward original wheels that have been converted into splits and thus some come without a guaranteed seal, or banded steels where alot of people run the inner tubes.

If the inner tubes with radial tyres are unsafe it's kinda scary to think how many more people are going down that route with there wheel choice.

Acrowot is that for oval racing or rallycross you use them? Or another discipline

[acrowot]

i do autograss and we all use tubes

[Alex_B]

Depends on the quality of the manufacture, with splits I think if they are machined correctly with a use of sealant between sections (not sure if thats possible just an idea that seems logical) then they shouldnt leak and banded steels if done correctly shouldnt leak air, mine don't and so that shouldnt be a problem (if they are leaking then the quality of the welds between band and wheel could be worrying and dangerous)