On TRX tires and more. A bit long

General conversations about BMW E28s and the people who own them.
Post Reply
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

On TRX tires and more. A bit long

Post by Mike W. »

I regularly peruse Curbside Classics. Some, but certainly not all interesting cars. But this came up on a writeup about 70's 911's. More than I ever knew about TRXs and radials in general. ( and to our younger readers, yes, we once had to pay a significant premium for radials)
First let’s discuss tire wall rigidity and tire break-away. In the early days of radial tires ( Michelin X) the sidewalls were very flexible allowing significant side wall deflection of several inches until the tread would final abrupt lift footprint reduction resulting in abrupt terminal understeer in front engined cars and abrupt terminal oversteer in rear engined cars. The high performance Michelin XWX tires series addressed this issue with significantly increased sidewall rigidity making this the ideal tire for high performance cars like the Ferrari 275 GTB in the 1960’s.

Later Michelin developed its TRX ( see Paul Niedermeyer’s article on the TRX in the CC blog) line of “performance” tires in the late 1970s and 1980, with significantly increased sidewall flexibility/ reduced sidewall rigidity unfortunately increasing sudden footprint breakaway characteristics combined with less than optimal tread patterns and less than optimal compound “stickiness”. The sidewall flexibility breakaway characteristics of the TRX tires ( up to 2-3 inches sidewall deflection during cornering) fundamentally contributed to the poor reputation
From geelongvic, about halfway down. https://www.curbsideclassic.com/vintage ... just-fine/

All of which is why TRX's have such a bad reputation here.
BMWCCA2
Posts: 4060
Joined: Feb 12, 2006 12:00 PM
Location: Central Virginia

Re: On TRX tires and more. A bit long

Post by BMWCCA2 »

You might factor cost, noise, and ride quality into why many here will use anything but TRX.
Federico
Posts: 545
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: On TRX tires and more. A bit long

Post by Federico »

There's literally an 80's magazine test, where they compare a 535i with TRX vs an Alpina with 16's. They even swap wheels between them and long story short the TRX's suck.
Federico
Posts: 545
Joined: Sep 16, 2013 6:38 PM
Location: Argentina / California

Re: On TRX tires and more. A bit long

Post by Federico »

Panici
Posts: 217
Joined: Aug 07, 2014 2:04 AM
Location: Canada

Re: On TRX tires and more. A bit long

Post by Panici »

Thanks for that, love to read a period piece.
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: On TRX tires and more. A bit long

Post by Mike W. »

Actually the TRXs came out better than I would have expected. Not great, certainly not up to P7 standards, which was a very good, perhaps the best tire for it's time, but I thought they'd be hammering on the TRXs and they didn't really.
Karl Grau
Posts: 9708
Joined: Mar 10, 2006 7:34 PM
Location: Sandy Eggo

Re: On TRX tires and more. A bit long

Post by Karl Grau »

Image
BillW in StL
Posts: 242
Joined: Feb 12, 2006 12:00 PM
Location: Midwest
Contact:

Re: On TRX tires and more. A bit long

Post by BillW in StL »

I am looking for a set. My departed father's Euro 380SL has BBS TRX wheels. Right now the tires are 20 years old, but the car is only driven a few hundred miles a year, top never up, and never on the highway. Still, if I could get a newer set of tires we could preserve the car as he had it.
Mike W.
Posts: 26872
Joined: Feb 12, 2006 12:00 PM
Location: California Whine Country

Re: On TRX tires and more. A bit long

Post by Mike W. »

BillW in StL wrote: Dec 25, 2022 7:36 PM I am looking for a set. My departed father's Euro 380SL has BBS TRX wheels. Right now the tires are 20 years old, but the car is only driven a few hundred miles a year, top never up, and never on the highway. Still, if I could get a newer set of tires we could preserve the car as he had it.
Oh, you can get them. But they're expensive and not very good tires. Actually prices look like they've come down some. Still expensive, but less than they were 5 or 10 years ago.

https://www.cokertire.com/catalogsearch/result/?q=trx
John in VA
Posts: 5278
Joined: Feb 12, 2006 12:00 PM
Location: Leesburg, VA

Re: On TRX tires and more. A bit long

Post by John in VA »

Some of the guys from the 2002FAQ forum have been purchasing 13" Pirelli Cinturato CN36s from Longstone Tyres - they also carry Avon & Michelin TRX tires. Prices are competitive. Tell them you heard about them from BMW2002FAQ for the royal treatment!

https://www.longstonetyres.co.uk/vintag ... /avon.html
https://www.longstonetyres.co.uk/michel ... s/trx.html
BillW in StL
Posts: 242
Joined: Feb 12, 2006 12:00 PM
Location: Midwest
Contact:

Re: On TRX tires and more. A bit long

Post by BillW in StL »

Still $350 a piece new for 70s technology tires. Good enough for a Mercedes SL but not at all in the budget. Something will come up used, but I will not go on the highway with tires more than 8 years old.

Side Note: I lost the tread to a rear tire on the way to 5er Fest 2006. Luckily it was held at the Tire Rack in Indiana. I got a great set of Bridgestones. Still on the car today....
Post Reply