02-13-2024, 04:28 PM | #1 |
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Ohlins R&T DFV spring rates for more aero
Howdy!
I have Ohlins R&T on my F82 M4 at the moment, and am planning on upgrading to more track oriented coilers next year. In the interim, however, I'm looking to adapt these to this year's track setup. I have a GT4 wing on order, as well as a GTS chassis mount splitter, and GT4 canards. I have the stock Ohlins springs on the coils. 513 lb/in front (90n/mm) and 1313 lb/in (230 n/mm). What spring rates would you recommend given the additional aero? I think the rear may be plenty stiff, but the front may need some slightly stiffer springs. In that case, is a re-valve necessary? |
02-13-2024, 05:00 PM | #2 |
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If you're in the Bay you can get in touch with Performance Shock - they're based out of Sonoma (Raceway). I'd imagine they could get you sorted with the right springs and any necessary revalving.
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02-13-2024, 05:55 PM | #3 |
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The GTS comes with F/R 400/700 lbf/in spring rates. The GTS front splitter is trying to reduce front lift more than it is trying to generate measurable downforce. Your R&T stock spring rates are fine. However, the R&T can achieve critically damped levels at 10 or so clicks from fully open so you can run higher rate front springs without revalving. You could go up 100-150 lbf/in, likely higher, without revalving. However, as suggested above, contacting PSI or 3DM or any other authorized Ohlins damper service shops to discuss your specific needs/goals is a good idea.
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02-14-2024, 12:47 AM | #4 | |
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But good to know on the stock GT4 spring rates - I agree that given that, the stock Ohlins rates look fine for now. I'll wait till I upgrade to some nicer multiway adjustable before messing with the spring rates/valves any more. Cheers! |
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02-14-2024, 06:54 AM | #5 | |
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02-14-2024, 01:49 PM | #6 | |
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The good news, I did get a callback from Barry and he is able to help me out. Super knowledgeable and helpful guy, just has been busy with many projects. |
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02-15-2024, 10:05 AM | #7 | |
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02-15-2024, 03:11 PM | #8 | |
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Cheers Jay |
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02-15-2024, 03:25 PM | #9 |
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Gooooooood luck. I have very very tight clearance with 19x10 ET25, plus a 15mm spacer and 275/35/19 PS4S. And lots of front camber. Ohlins is known to be tight up front.
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02-20-2024, 12:16 PM | #11 | ||
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02-20-2024, 12:34 PM | #12 | |
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I want to pullthe trigger on some 18x10.5 et36 bimmrworld wheels this summer but want to make sure they'll fit before I do. I'm a year or so away from switching to MCS. |
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02-20-2024, 01:18 PM | #13 | |
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https://f80.bimmerpost.com/forums/sh...&postcount=191 then you’d need a 10.5” wide wheel with an effective offset of +5 (10.5et5) to clear the R&T strut. This is too aggressive of an offset for the outer fender even with 4 deg of negative camber. |
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02-20-2024, 09:44 PM | #14 | |
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02-21-2024, 08:50 AM | #15 |
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You’re welcome.
If you’re fine with 3 mm of clearance (a lot of track guys run with 3 mm of clearance between the tire/wheel and strut/spring) then you’d probably be able to run a 10.5et10 with a 275, maybe a 285 if it doesn’t run wide or doesn’t have a large bead protector, without hitting the strut/spring. Must track guys run a 10.5et20 with 285 or 295 but’s 10.5et10 would stick out (frontspacing) ~0.4” more. Unfortunately, it’s still too aggressive for the front fender. |
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02-21-2024, 10:20 AM | #16 | ||
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02-21-2024, 10:45 AM | #17 | |
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A poster above said he’s able to run a 10et20 wheel with clearance. That would mean you’d be able to get away with a 10.5et13, maybe et14, but that’s still too aggressive for the front fender. It looks like you’ll have to hold off on getting the BW 10.5et36 wheels. |
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02-21-2024, 11:05 AM | #18 | |
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