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MG MGA - Tubeless Tyres

Tyres again but a different question.

Has anyone run their A on tubeless tyres on disc wheels. I am sure in the distant past that I have run on tubeless probably in the early 70s.

I got my new Cinturatas fitted yesterday and asked the very helpful local garage to try and go tubeless and they tried but they said it couldn't be done because of the valves being wrong.

I suppose 2 questions. Firstly does anyone understand the problem. Secondly does anyone run tubeless?

Paul
Paul Dean

Yes you can run tubeless with MGA steel rims, but the original rims were not deemed "safety rims" that prevent a tire from dismounting itself from the rim should it go flat. For some photos & explanation, see attached link to Barney's site:

http://mgaguru.com/mgtech/wheels/wl106.htm
Nick Kopernik

Many thanks Nick.I had been on Barney's site and read everything about fitting tubes but not found the very useful one you quote.

By the way is it the same valve as used in modern cars. I have heard mention of it being a so called 'Tractor Valve'??? I have twice tried to go tubeless and the mechanic has muttered about being the wrong valves.
Paul Dean

Paul

I have run since my rebuild in 2016 with tubeless tyres on disc wheels. I always check and adjust tyre pressure and have had no problems. Mileage is about 1000/year, no mountain climbing or similar.

No problem sourcing tyre valves, the tyre man supplied and fitted the modern stubby ones.

Cheers
Dave
Bolney Coupe

Paul, I've run my MkII with tubeless tires for several years with no problems. In fact, I've worn out the tread by the time the 8-10 year life of the tires has expired. I do mostly spirited windy/twisty mountain road driving. I do check my tire pressures regularly. I've never heard of a problem getting tubeless valves for the rims. Perhaps you should try a different tire store.

Jud



J K Chapin

valve stems for 5/8" hole
-TR415- normal length
-TR15- short
William Revit

Tire valve openings have different diameters, so you either need to buy the proper diameter tire valve, or use a valve collar to make up the difference in diameter. A #TR15 (no relation to Triumph cars/motorcycles!)valve stem was very common from the 40's through the 60's, and it had a wide stem at 0.65 in. The #TR15 was replaced by the #TR13 size which is narrower and pretty much the standard today at 0.46 in. I run wire wheels on my car and still need to use tubes. The wire wheels on the car are newer Dunlops, so they came with an opening for the "modern" #TR13 valve. Now my spare is one of the original ww's that came with the car and it had an opening for the old #TR15 valve stem. The solution was to use a valve collar to allow the narrower #TR13 valve to snugly fit into the wider #TR15 opening. Pics of valve stems & collars attached:





Nick Kopernik

I run my A tubeless (Continental 165R15) on Moss spoked wheels. The wheels came with the nipples sealed with silicone. No problems after 3 years.
Art Pearse

The lip doesn't simply hold the tire on, it also gives the tire bead a much better sealing surface. If your tires run low and you take a hard corner, the loss of seal can cause rapid deflation and loss of control.

That said, you can run tubeless tires successfully if you ensure the pressures remain optimal. I've run about 100K tubeless miles in my early B, which has essentially the same wheels as MGA, only wider. I run tubes in most of my cars however. installed properly, they are as reliable as a tubeless setup.

Keep in mind those plastic collars are meant for inner tubes, not tubeless. If going tubeless, get the proper size valve stem.
Steve Simmons

Wheel rims can have two different hole sizes for the valve stem. All MGs of similar vintage have the larger holes. You can delete the tubes and install tubeless tire valves. Just use the fatter stems, and it's good to go. See here:
http://mgaguru.com/mgtech/tires/ti120.htm

I was running tubes with wire wheels in the late 60's. My current steel wheel car came to me without tubes in 1977. I put it back on the road in 1986 and have been running tubeless for another 480,000 miles since then, including race tires and lots of competition all through the 90's.

Always running original 4J wheels with no safety rims, never any problem. The safety rims come to be useful if you run less than 5-psi pressure in the tires and keep driving just before they go dead flat. But you should know by feel of bad handling when a tire pressure gets low.

I have never in my life had a tire come loose from the rim. There have been a few instances of instant flat from road hazard damage, but just stopped immediately to change the tire.
Barney Gaylord

I am all sorted. Having spoken to my specialist tyre suppler yesterday the guy who answered was only aware of the standard tubeless tyre valve. But he then spoke to someone else and was told that when they fitted tyres they had 2 types of valve available and fitted the one required. The alternative they have was referred to as ‘fat valves’ which is the 15mm version not the modern 13mm version. Slightly bizarrely they don’t sell valves but he is going to send me a set of ‘fat valves’. They can’t charge me as they aren’t on their price list so I ma getting them free, mind you I have just bought 4 Pirelli’s.

It is interesting from the response to this that tubeless seem a lot more popular in the US than the UK!
Paul Dean

This thread was discussed between 14/01/2022 and 19/01/2022

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