Current and future set-up

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L.Tigre
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Current and future set-up

Post by L.Tigre »

I'm trying to get a line on my current wheel and tire size, and suspension set-up, in order to determine what tires to get on my newly purchased rims. The car is relatively new to me.

The current setup is a tire size 215/65R15 on a 15inch BBS OEM wheel. The wheel says "ET15" right on it. Same wheel and tire front and back. So far so good.

But: How wide are these rims? I took a measuring tape and estimated between 8.5" - 9". Seemed pretty wide... they don't look that wide and with 215 tires that seemed like too wide a rim. But on the rim itself it says 'RX224' Can I take that as 224mm wide?... which would be around ~ 8.8" wide?

If so then I feel a lot better about my four already-purchased on-their-way-here 16x8.5" ACT/Ronal rims (ET10). I dunno, the current wheels do not seem that wide to me. Or maybe I thought you couldn't get a 215 tire on a nearly 9" rim.

Bonus question: any suggestions for a tire to go on the new 16x8.5 rims? I feel like the wheel wells could be just a bit more filled-up, but not sure how far I can go before I'll get rub. The job is made complicated by lack of proper suspension knowledge. I'm not sure but feel the car may be very-slightly lower than stock (the shocks are relatively new vintage, within the last 5 years). Ground clearance at the door sill as-is is 7", maybe 7.25". Some pics attached. Suggestions?
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Ralph in Socal
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Re: Current and future set-up

Post by Ralph in Socal »

First picture at the top 7 1/2 J x 16 H2

7.5 inches wide

I've run 245/50 16 rears and 225/50 up front on 8 inch et11 wheels. Not sure how those would equate to your new wheels. Good luck

Ralph
There is a very fine line between "Hobby" and Mental Illness.

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L.Tigre
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Re: Current and future set-up

Post by L.Tigre »

Ralph in Socal wrote: Sun Sep 11, 2022 11:52 pm First picture at the top 7 1/2 J x 16 H2

7.5 inches wide

I've run 245/50 16 rears and 225/50 up front on 8 inch et11 wheels. Not sure how those would equate to your new wheels. Good luck

Ralph
Thanks - I didn't see that 7 1/2, or didn't get it.

Good to know 225-50 on R16s works in the front. And I think they can get that width onto an 8.5" rim. So likely that's what I'll do. Although I am tempted for 55s just to keep the same diameter...
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jps635
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Re: Current and future set-up

Post by jps635 »

The rub point to beware of on the front is the inside of the tyre on the strut.
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L.Tigre
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Re: Current and future set-up

Post by L.Tigre »

jps635 wrote: Tue Sep 13, 2022 9:04 am The rub point to beware of on the front is the inside of the tyre on the strut.
Yes, but I think/hope the ET11 helps me there? The calculators online seem to think it’s ok for strut clearance, or at least only slightly worse than the current tire.

But I am just as worried, maybe more worried, about the fender rubbing with an 8.5 wide ET11 wheel. I would like to go to 225/55 to maintain diameter, if I can get away with it in front….
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Ralph in Socal
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Re: Current and future set-up

Post by Ralph in Socal »

jps635 wrote: Tue Sep 13, 2022 9:04 am The rub point to beware of on the front is the inside of the tyre on the strut.
Agree with this, however, tire height can also cause rubbing on the underside of the spring cup

I think your et10 will pull the wheel out further so you may not have an issue on the inside.

8 x 17 inch style 5 are et 20 and I've run 235/45s and do not rub the strut. It's very close but no rub

Ralph
There is a very fine line between "Hobby" and Mental Illness.

85 635csi Zinno Auto
84 528i Euro
83 635 Euro Arktik
81 528i Kastanien 5-speed
88 528e Bronzit (Granpa Car)
86 535i Auto (For Sale)
81 633 csi (retired)
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