X5 Bigger Wheels...
Discussion
A friend is who is buying one of the new X5 SD4.0, is thinking about putting some 'big' non std wheels on, after some basic maths it looks as though the rolling diameter will increase by approx 8%, other than the speedo been out is this going to cause any of the on-board systems to freek? Invaladate the whole warranty? As I said its a friend and to not to my taste, any real world experience appreciated, thanks.
Hiya
As already explained, by utilizing the correct tyre profile when going up wheel sizing to try and keep as close to the original rolling radius of the original tyres, everything should be ok.
How big a wheel is he intending to go to?!
Also, just becuase you go bigger wheels doesn't automatically mean it'll drive like it's on cobbles. That's simply not true. You should do things that are recomended and proven to work. Look at what some of the high end BMW tuners do for larger wheel/tyre packages and follow those. You know they've been extensively tested and proven as well.
The trouble arises when people put on non tried and tested wheel sizes and tyre sizes etc
Cheers, Dennis!
As already explained, by utilizing the correct tyre profile when going up wheel sizing to try and keep as close to the original rolling radius of the original tyres, everything should be ok.
How big a wheel is he intending to go to?!
Also, just becuase you go bigger wheels doesn't automatically mean it'll drive like it's on cobbles. That's simply not true. You should do things that are recomended and proven to work. Look at what some of the high end BMW tuners do for larger wheel/tyre packages and follow those. You know they've been extensively tested and proven as well.
The trouble arises when people put on non tried and tested wheel sizes and tyre sizes etc
Cheers, Dennis!
I have OEM 20's on mine...moved to non RFT tyres to try and get a slightly better ride which it is but it's not much better. I wouldn't dream of putting bigger wheels on without getting some aftermarket suspension to help out...I've read reviews/threads of Eibach and KW suspension both of which are said to improve the ride whilst also being as good or better dynamically. He might be okay if he lives in a part of the world which has no pot holes or speed bumps....
If you do go bigger with lower profile tyres then it WILL be a harsher ride and will tramline more. Thats simply a matter of physics on both counts. Other aftermarket suppliers with "tested and developed" set-ups ignore comfort and noise in the interests of performance and handling.
An 8% change in gearing will also alter the speedo and associated systems as the car will be unaware of it's true speed which will upset the ABS, ASC systems etc.
As you say, it's for a visual effect only and if you can put up with the reduction in ride quality, then fine, but do not change the rolling circumference by 8%, use lower profile tyres.
8Tech.
An 8% change in gearing will also alter the speedo and associated systems as the car will be unaware of it's true speed which will upset the ABS, ASC systems etc.
As you say, it's for a visual effect only and if you can put up with the reduction in ride quality, then fine, but do not change the rolling circumference by 8%, use lower profile tyres.
8Tech.
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