02-27-2024, 08:20 AM | #23 | |
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Re coilovers; I had the same thought process and have run BC/D2 coilovers numerous times as well as bespoke Nitron coilovers on a previous DC5 many moons back etc But for me and my wants; they were not needed on my F31; I didn't need/want the adjustability nor the continuous caring of them to stop them from corroding/seizing etc, which they will... Shocks and springs would be the right call if you don't want to drop stupidly low or need the adjustability... If you do want that; you'll not go wrong with BCs (fitted properly, set up properly and dialled in with a decent tracking/alignment and fast road set up etc)
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dietMcar7.50 |
02-27-2024, 08:36 AM | #24 | |
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danb19792318.00 |
02-27-2024, 09:08 AM | #25 | |
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COILOVERS ON XDRIVE I did a lot of research when I was considering coilovers on my XDrive. I did a lot of chassis height and tire/fender gap measurements too. Here’s something that most people do not consider until they have spent big money and it’s too late. The minimum and maximum drop ranges for front and rear are extremely important because XDrive is limited. XDRIVE DESIGN GEOMETRY If the front of any XDrive is lowered by more than about 1.5”, then it gets outside of XDrive design geometry and risks breaking front drive shafts. So most people will look at the front drop range, say it’s 1.2”-2.2”. They think okay that’s no problem, I still can drop my XDrive between 1.2”-1.5”. But they fail to carefully consider the rear drop range too. ACCOUNTING FOR XDRIVE REVERSE RAKE For example, using measurements from my XDrive, BMW builds in about 0.75” of reverse rake. So the front tire/fender gap is about 0.75” more than in the rear. The most aesthetically pleasing look is typically when the front and rear tire/fender gaps are equal. So say that the front of the XDrive is dropped by 1.5”. Well that makes up for the 0.75” reverse rake difference, plus drops it another 0.75”. So now, for the front & rear tire/fender gaps to be equal, then the rear must now be dropped by 0.75”. REAR DROP RANGE IS CRITICAL Say the front is only dropped by the minimum 1.2” capable of that coilover. Then the rear would have to be dropped by 0.45”. So the rear coilover needs to have a drop range of 0.45” to 0.75” to make the front and rear tire/fender gaps equal. BUT most of the coilovers that claim to fit XDrive have a much higher minimum drop range. For example, 1.2”-2.2”. They drop the rear too much. So instead of dropping by an aesthetically pleasing Front 1.5” & Rear 0.75”. The drops end up being F1.5”/R1.2”. The rear ends up looking like the body is taking a squat on top of the rear tires. Lowering the front more to try to balance it out gets into that breaking driveshafts range. ACTUALLY THERE ARE FEW GOOD CHOICES FOR XDRIVE COILOVERS In my research, if I was going to choose a coilover, it came down to the KW V2 Street Comfort being the best choice for ride, quality and proper drop ranges. I ended up going with separate Koni dampers and Eibach XDrive springs. If didn’t make sense to me to pay double, just to say that I had coilovers when the same handling functionality could be had in separates for less than half the price. Hope this helps! |
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dietMcar7.50 |
02-27-2024, 09:10 AM | #26 | |
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Do you know your shocks need replacing or are you just wanting to do that, similar to what I did? It could be worthwhile just running lowering springs for now and seeing how you get on then look to replace the shocks at a later date...
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02-27-2024, 10:04 AM | #27 | |
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02-27-2024, 10:20 AM | #28 |
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I’ll have to figure out a price. They have about 25k miles of daily driving on them. No tracking or anything like that. Nothing at all wrong with them. Working perfectly when I deinstalled them. I sometimes swap parts off/on my car to test different things. I just happened to take them off. I’m pretty sure that I save most of the other bits like top hats, spring perches and bump stops that I can include. So should have most of what you would need except for coding out EDC.
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dietMcar7.50 |
02-27-2024, 10:24 AM | #29 | |
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02-27-2024, 10:57 AM | #32 |
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@dietMcar, for the suspension work, are you DIY or having a shop do it? suspension work can cost a decent amount so i think it's important to get it somewhat correct on this attempt. i understand about low budget but the initial savings "cheaping out" may end up costing you more in the long run and this can be applied to other mods and things in life as well.
i've read enough problems with BC on this platform and think you'd end up regretting these, just my personal opinion on BC for this platform. i have/had different coils on other cars and between adjusting the corner heights, preload, compression and or rebound, creaking and clunking, i find it to be annoying continually f'king around with'em. maybe it's just me, but i read about others with the same issues and it doesn't matter if the coils were cheap or expensive. fyi, there's been more than a few members that have had issues when lowering x-drives greater than 1.5"(38mm). as you lower, the front axle's geometry and forces on it change and some have had the axle fail by shear. the axle also starts to unseat from the differential as you lower and some have had the axles pop out. while some have lowered x-drives more than 1.5" without issue, i've read enough posts where problems arose from lowering an x-drive too much. the link below is a thread where they determined what the max lowering should be. i'd follow the advice from such thread and not lower an x-drive more than 1.5" or 38mm. https://f30.bimmerpost.com/forums/sh...1514736&page=2 i'd "buy once cry once" and get eibach pro-kit springs, F80 bumpstops and Bilstein B4 damptronic(if you can find them)...OR Eibach, F80 bumps, Koni SA and edc delete, set+forget+cry less...OR KW street comfort or V1 with edc delete for coils, 1.5" max for x-drive. get new strut mounts with all of these and new spring seats and dust protectors if changing dampers. |
02-27-2024, 11:54 AM | #33 |
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FYI- a practical way that I confirmed the XDrive drop limit was to look up all of the available XDrive lowering springs that I could find from name brand manufacturers like Eibach, H&R, Dinan, etc. None of them sell XDrive springs with estimated front drops lower than 1.5”/1.6”. Obviously they have the engineering to know what the XDrive design geometry limitations are. And they aren’t going to sell a spring that drops lower, and risk liability and lawsuits. Imagine if a front driveshaft broke because the springs dropped it too low, and there was an accident where someone died? The financial risk to too high.
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