Rear Shock Mounts for ST XTA Coilovers

hson10 · 11-22-2023, 10:15 PM

Need some help with looking for the correct rear shock mounts for ST XTA coilovers. My car has OEM EDC so I got the coilover part number that would be compatible for EDC-equipped cars (but I will leave them unplugged).

Do I purchase a new OEM EDC rear shock mount kit (i.e., something like this: https://www.turnermotorsport.com/p-1...SABEgLQifD_BwE)
or go with aftermarket mounts (I saw some folks recommending Monroe, but I think they don't make a 14mm ID one)? Car has around 115k mi so it will definitely need a refresh on RSBs.

The main thing I'm confused on is that it looks like there is a 10mm/12mm/14mm option for rear struts, so wondering if anybody who has ST XTAs / aftermarket EDC-compatible coilover kits purchased a new EDC rear shock mount kit, and if so, whether they went with 12 or 14mm?

I have done a ton of searching on this forum as well as on E9x owners on facebook and couldn't find a definitive answer on which rear shock mount I needed. Any help would be very much appreciated!

Thanks in advance

Redd · 11-25-2023, 04:07 PM

Rear strut mounts are 10mm for non-EDC and 12mm for EDC. I'm not aware of 14mm RSM. I just installed my TracTive a little while back and they are definitely 10mm or 12mm.

If the ST coilovers are direct replacement for non-EDC dampers then get the 10mm ones. Even if you made a mistake you can go to a machine shop and get the metal sleeve bored out to 12mm.

Monroe does make a 10mm one. I would recommend just going Powerflex Black and not ever think about them again. Zero impact to NVH.

M3SQRD · 12-09-2023, 03:38 PM

Most aftermarket rear dampers use a 12 mm shaft OD. BTW, I’d also recommend Power Flex black RSMs - no increase in NVH.

fengrr · 03-06-2024, 09:49 PM

Quote:

Originally Posted by M3SQRD

Most aftermarket rear dampers use a 12 mm shaft OD. BTW, I’d also recommend Power Flex black RSMs - no increase in NVH.

These only for the non-edc 10mm right?

M3SQRD · 03-06-2024, 11:11 PM

Quote:

Originally Posted by fengrr

These only for the non-edc 10mm right?

I think you can get non-edc 10 mm and 12 mm. I haven’t checked in a while but I’d be surprised if they dropped a product. Dinan has RSM for edc.

11-22-2023, 10:15 PM	#1
hson10 Private First Class 140 Rep 100 Posts Drives: '21 A90 Supra 3.0, '11 E92 M3C Join Date: Mar 2018 Location: SF Bay Area, CA iTrader: (0) Garage List 2017 BMW M2 [0.00]	Rear Shock Mounts for ST XTA Coilovers Need some help with looking for the correct rear shock mounts for ST XTA coilovers. My car has OEM EDC so I got the coilover part number that would be compatible for EDC-equipped cars (but I will leave them unplugged). Do I purchase a new OEM EDC rear shock mount kit (i.e., something like this: https://www.turnermotorsport.com/p-1...SABEgLQifD_BwE) or go with aftermarket mounts (I saw some folks recommending Monroe, but I think they don't make a 14mm ID one)? Car has around 115k mi so it will definitely need a refresh on RSBs. The main thing I'm confused on is that it looks like there is a 10mm/12mm/14mm option for rear struts, so wondering if anybody who has ST XTAs / aftermarket EDC-compatible coilover kits purchased a new EDC rear shock mount kit, and if so, whether they went with 12 or 14mm? I have done a ton of searching on this forum as well as on E9x owners on facebook and couldn't find a definitive answer on which rear shock mount I needed. Any help would be very much appreciated! Thanks in advance __________________ 2021 A90 Supra 3.0 Nitro Yellow, 2011 E92 M3 Comp Jerez Black Instagram @hans.device Last edited by hson10; 11-22-2023 at 10:37 PM..
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11-25-2023, 04:07 PM	#2
Redd Brigadier General 3900 Rep 4,165 Posts Drives: 2010 BMW E92 M3 Dakar Edition Join Date: Jul 2015 Location: Malaysia iTrader: (0)	Rear strut mounts are 10mm for non-EDC and 12mm for EDC. I'm not aware of 14mm RSM. I just installed my TracTive a little while back and they are definitely 10mm or 12mm. If the ST coilovers are direct replacement for non-EDC dampers then get the 10mm ones. Even if you made a mistake you can go to a machine shop and get the metal sleeve bored out to 12mm. Monroe does make a 10mm one. I would recommend just going Powerflex Black and not ever think about them again. Zero impact to NVH.
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12-09-2023, 03:38 PM	#3
M3SQRD Major General 2161 Rep 5,548 Posts Drives: E92 M3,G20 330ix,F22 240iX,F82 Join Date: Jun 2009 Location: Mid-Atlantic iTrader: (11)	Most aftermarket rear dampers use a 12 mm shaft OD. BTW, I’d also recommend Power Flex black RSMs - no increase in NVH.
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