PLEASE HELP! Is there alternative to the 220/55 VR 390 Metric tire? I have a 85 BMW 635CSI…..?

Should I just change out the wheels and avoid this tire all together?? I have a set of 17″ BMW wheels that I am told will fit this car? ANY ADVICE or KNOWLEDGE would be appreciated!

5 Answers

  • AndyCappo
    2 decades ago

    “In the 1980s BMW fitted tyres known as TRX to some higher performance models. TRX were advanced for their time and used a special design of wheel and tyre lip to hook the tyre to the rim for improved high stress cornering performance. To avoid the dangers of fitting normal tyres to a TRX rim they were all made in metric sizes which only a TRX tyre would fit. Only Jaguar and a few other manufacturers used TRX and it became the Betamax and 8-track of tyre design.

    TR means “Tension Repartie” (spread tension). Michelin’s design called for a shallower rim that allowed freer movement of the tire sidewalls under compression but provided a progressively increasing lateral stiffness during cornering. This was thought to be a boon for the high-end luxury-sporty car market as it in theory would allow for a more comfortable ride without sacrificing cornering ability through controlling the slip-angle with sidewall stiffness. In essence BMW thought they were providing the ride quality of a 70-series tire with the handling benefits of a 60-series profile.

    Modern tyres have better tread patterns and rubber compounds than TRX. TRX are also quite expensive and harder to get hold off than modern tyres. When the TRXs on my 635CSi wore out I bought and refurbished some used 15″ cross spoke alloys and bought modern tyres.

    TRX tyres may be spotted by a designation of 220/55VR390 or 415 on the tyre sidewall.”

    When your current tyres become worn out I’d definately swap the metric wheels for a set of imperial alloys. You just need to check that the PCD (stud pattern – should be 5×120) offset (ET20-25) and centre bore (72.56mm) are compatible. Alloys as fitted to E34s, E28s, E31s and E32s should all fit without a problem.

  • bracken46
    2 decades ago

    If they were the tires the factory recommended for the car and you’re still running the original rims, I’m sorry, you really should stick with them. Having specialized metric tires is nothing new for European car owners; most of them just bear it.

    But if it really bothers you to have to special-order tires, there are ways to get around it. You could work with a BMW dealership that does steering/suspension and alignment work (NEVER a tire store!) to find the right U.S. tire to fit your rims, and have them mess around with your car to find out the inflation they’re supposed to run (because it’ll probably be different than BMW recommends for the original tires).

    Your second option is to change out your wheel/tire package; go for larger rims for the same diameter wheel/tire assembly, and just buy matching low-profile U.S. spec tires from now on. (Again, do this at a Bimmer specialty shop, not a place like Les Schwab.) Don’t expect the ride quality to be the same, though. And the tires may be just as expensive in the end.

    Good luck! If you would like some more information, feel free to contact me.

  • Christopher
    2 decades ago

    Where are you located? Everything I’ve read here in NA says ditch those rims.

    Bimmer Magazine does buyer guides for specific models, and went into this in some length. Here’s the URL, but most of their content not online. I can get you the issue number with the 6 series information if you’d like.

    Good luck. You’ve got a nice car there — someday I’d love to have a 1988 M6!

  • swissnick
    2 decades ago

    Choose a 225/55 VR 17 – these 5millimeters more width (20% of an inch) shouldn’t have any effect.

    Then you easily can keep the wheels – and there is a much bigger choice in this tyre size.

    If you don’t believe, ask a tyre dealer.

  • ?
    5 days ago

    Michelin Trx

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