Tyres.

[mdmax72]

Hi all.
I’m in a dilemma. Just had my Michelin XAS tyres swapped over from Steel wheels to aluminium wheels. The aluminium wheels have the necessary rib on them to use tubeless tyres. Now my steel wheels didn’t have the rib on them, so l used inner-tubes to help the tyre stay on the bead. So with the new aluminium wheels l got the tyre fitter to fit them without inner tubes.

Question is am l right in thinking they will be fine? Without the inner Tubes?

What have you all done?

[Ashley James]

As long as the tyres are tubeless, they’ll be fine.

[Peter Roberts]

I have just fitted XAs tyres to mine. They are clearly marked "TT" if they are the tubed type so obviously need tubes. If tubeless i understand it is not a good idea to fit tubes as there may be an issue with overheating as tubeless tyres are not meant to have tubes.

[mdmax72]

roy mawbey wrote:
1). Nearly 50 years ago I was driving my 356 on Michelin X tyres and did so for years. I always had inner tubes fitted. Then there were discussions about the wheel well not being deep enough?? on 356 wheels to accept tubeless tyres. When I first started using Firestone the guy said the valve is important and inner-tubes are not really necessary.

I think when the Michelin X first came out it was a tube type tyre. the Firestone F560 is a tubeless tyre, but because it is 80% profile you can also fit an inner tube if you want to.
Up untill a point all tyres had inner tubes. then they developed a way of sealing the inside of the tyre so it could be run tubeless on normal rims. This was only a short period, before the rims were then improved with the addition of the safety rib. I would suggest if you don't have the safety rib then fit an inner tube. also if in doubt fit a tube. http://www.longstonetyres.co.uk/page/cl ... nner-tubes However don't fit an inner tube in anything less than a 70% profile tyre (so don't put a tube in a 195/65R15)


After reading this quote some time ago from Dougal. I got it in my head it was ok to use the TT tyre on a wheel that had the safety rib on the wheel. My tyre fitter wasn’t to sure if it was a good idea to fit the tyre without the tube even though the tyres are dated 2013/14. So this is we’re I’m confused. Dougal also stated if in doubt fit a tube. I guess to be on the safe side I’m best to fit the tubes as l have them. But I’d like to know either way with these tyres being a newish tyre can they be safely run without a tube on a wheel with the safely rib?.

[Dougal Cawley]

You must fit an inner tube with a 165HR15 XAS because as it says on the side wall of the tyre "tube Type" meaning that the tyre carcass has not been sealed and may be pourous.

Unofficially you might get away with it, but i could not encourage you to try it. i would go back and have some tubes fitted Michelin are in my mind the best https://www.longstonetyres.co.uk/offset ... 5e-13.html

Principally i think Rich has covered most of the detail there is more detail about tyre options on here

https://www.longstonetyres.co.uk/classi ... e/356.html

I think the basics are
If the tyre is a tube type tyre (eg XAS) fit an inner tube
if the rim does not have the safety ribs fit an inner tube
you can fit an inner tube in any tyre of the Porsche sizes 165R15 or 185/70R15 regardless of weather it is described as "tube type" or "tubeless", you should not fit an inner tube in any tyres 195/65R15 or 215/60R15.

Interestingly in 1973 when Porsche started fitting the new super duper low profile 215/60R15 Cinturato CN36 to the rear of the RS & Carrera cars they were tube type tyres. This is the only tyre i have come across that is lower than 70% profile that was designated as tube type. very shortly after they produced them, they stopped making them tube type and to my knowledge have not made anything less than 70 profile tubeless since.

Also very shortly after that they developed the safety rib and generally all wheels now have them. there was a breif period also where they were fitting tyres without tubes to wheels without the safety rib. but they soon stopped that and ribbed them all.

Its all part of the evolution of cars and tyres. and they evolved together. sometimes a tyre manufacturer would develop new technology and cars would evolve to take advantage of it. but i think often it was probably the other way round, where car manufacturers would make new demands on the tyre manufacturers who would come up with ways to offer the cars more comfort, or grip or directional stability, or maybe just look cooler. (i think i get to use a big word.) they have a symbiotic relationship.

[POR68]

This is interesting but confusing. The consensus and experience among most long-time 356 owners has been that it is not necessary to use tires with tubes even though the original 356 wheels do not have the "safety bead". With most modern tubeless radials inner tubes are reportedly not necessary on our cars and this topic has been explored extensively elsewhere and as long as you keep an eye on pressures and have the right valve stem, they are fine. I have driven on the track and on drives over 1000 miles in a couple of days on my Veredsteins without a problem.

[Dougal Cawley]

This is interesting but confusing. The consensus and experience among most long-time 356 owners has been that it is not necessary to use tires with tubes even though the original 356 wheels do not have the "safety bead". With most modern tubeless radials inner tubes are reportedly not necessary on our cars and this topic has been explored extensively elsewhere and as long as you keep an eye on pressures and have the right valve stem, they are fine. I have driven on the track and on drives over 1000 miles in a couple of days on my Veredsteins without a problem.

I would suggest you are right, that if you run without inner tubes be very vigilant on your tyre pressures, with regular checking.

However any decent tyre you fit to these cars, can fit an inner tube. ie any 165R15 or 185/70R15 can fit an inner tube. weather they are called tubeless tyres or tube type. you can put an inner tube in any of them.

you should not run an inner tube with a 195/65r15. which doesn't really matter because a 356 will not handle as well on this size tyre. i know they are cheap, but is it worth sacrificing the handling (and look) to save a few quid?

they did run inner tubes in 60% profile tyres back in the day, but they soon stopped doing it because it wasn't very good.

they did run tubeless on wheels without the safety rib. However they didn't do that for long either because it was better with a safety rib