adjusting preload on coilovers

robc1976 · 06-29-2013, 03:08 PM

Want a bit of classification here on adjusting preload on my BC BR coilovers. I think I put a bit too much preload on them.

The process is easy:

adjusting preload:

1. Spin adjuster ring up to spring so it is tight
2. Spin locking ring up
3. Then tighten adjuster ring so there is a gap the size of the spanner wrench
4. Then lock in place by spinning up lock ring

I think I messed up on on step #1...how tight do you get the spring before adjusting preload? I tighten spring by hand by screwing it up tight...then tightened more with spanner wrench so there was absolute no movement...then adjusted preload the gap of the spanner. What would happen if it was to much preload? My springs are riding rougher than normal.

Dr. G · 06-29-2013, 03:22 PM

Are the BC springs linear?

ashmostro · 06-29-2013, 04:06 PM

BC should specify how much preload to put in millimeters- use that spec. As for how much to "pre-tighten" you just want it so the adjuster is snug with the spring and the spring is properly seated on both perches, then take your baseline length measurement and preload from there. If you're off by a millimeter here or there you aren't ruining anything.

Then set your ride height using the lower shock tube collar. One of the nice things about the BC coils IMO.

PS, too much preload can feel harsh assuming you are correctly damped. But too much preload needed can also be a sign of too soft or too short of a spring if you are having to preload immensely to get to the desired ride height (which shouldn't be the case on the BC setup anyway for aforementioned reasons).

robc1976 · 06-29-2013, 05:08 PM

Quote:

Originally Posted by ashmostro

BC should specify how much preload to put in millimeters- use that spec. As for how much to "pre-tighten" you just want it so the adjuster is snug with the spring and the spring is properly seated on both perches, then take your baseline length measurement and preload from there. If you're off by a millimeter here or there you aren't ruining anything.

Then set your ride height using the lower shock tube collar. One of the nice things about the BC coils IMO.

PS, too much preload can feel harsh assuming you are correctly damped. But too much preload needed can also be a sign of too soft or too short of a spring if you are having to preload immensely to get to the desired ride height (which shouldn't be the case on the BC setup anyway for aforementioned reasons).

I tightened it to much I think lol! ...lowering is awesome on these, almost to easy. Took a lot of critiquing to get them perfect but was worth it...haven't adjusted ride height for a couple of months

06-29-2013, 03:08 PM	#1
robc1976 DIYER 614 Rep 5,521 Posts Drives: E90 335i Join Date: Mar 2012 Location: Illinois iTrader: (14)	adjusting preload on coilovers Want a bit of classification here on adjusting preload on my BC BR coilovers. I think I put a bit too much preload on them. The process is easy: adjusting preload: 1. Spin adjuster ring up to spring so it is tight 2. Spin locking ring up 3. Then tighten adjuster ring so there is a gap the size of the spanner wrench 4. Then lock in place by spinning up lock ring I think I messed up on on step #1...how tight do you get the spring before adjusting preload? I tighten spring by hand by screwing it up tight...then tightened more with spanner wrench so there was absolute no movement...then adjusted preload the gap of the spanner. What would happen if it was to much preload? My springs are riding rougher than normal. __________________ JB4 G5, Stage 3 LPFP, Stage 2 MOTIV PI, VM 6466 ST, Custom OCC W/ SS lines, ER FMIC, ER CP W/HKS BOV, M3 control arms, M3 guide rods, M3 upper links, M3 front & rear sway-bars, HPA rear toe arms, Wavetrac LSD, HPF Gen 2, DEFIV kit, KW clubsport, Delrin solid SF bushings, stoptech rotors, Rogue Tranny Mounts, 1M bumper, M3 CF hood, M3 fenders, M3 OEM sideskirts, Mtech rear bumper, CSL trunk, MORR VS8.2 rims 245/295
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06-29-2013, 03:22 PM	#2
Dr. G Major General 278 Rep 5,062 Posts Drives: Black e92 335i Join Date: Apr 2010 Location: Brampton, Ontario iTrader: (32) Garage List e92 BMW 335i [8.84]	Are the BC springs linear? __________________ JB4 / OSS Angel Eyes / Downpipes / F1-Racewerks FMIC / Custom Meth Kit / BMS DCI / ER Chargepipe / HKS BOV / BMS Meth Elbow / BMW Performance Exhaust / Carbon Fiber Inlay Quad Tips / 19" Miro 111 / Front Aero Lip / M3 Sides / VRS CSL Trunk / Mtech Rear / DD CF Quad Finned Diffuser / LCI Tails / BBK / Smoked Reflectors / F1 Euphoria LED Interior / License LED's / GT 5000k Corners / 5000k HID Fogs / Air Scoops / LED Turn Signals / FK Silverline Coilovers / HPA endlinks / Vibrant Resonators / Osram CBI 5000k D1S
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06-29-2013, 04:06 PM	#3
ashmostro Brigadier General 1254 Rep 4,088 Posts Drives: 2020 M4cs \| 2022 M550i Join Date: Jan 2013 Location: Falls Church, VA iTrader: (27)	BC should specify how much preload to put in millimeters- use that spec. As for how much to "pre-tighten" you just want it so the adjuster is snug with the spring and the spring is properly seated on both perches, then take your baseline length measurement and preload from there. If you're off by a millimeter here or there you aren't ruining anything. Then set your ride height using the lower shock tube collar. One of the nice things about the BC coils IMO. PS, too much preload can feel harsh assuming you are correctly damped. But too much preload needed can also be a sign of too soft or too short of a spring if you are having to preload immensely to get to the desired ride height (which shouldn't be the case on the BC setup anyway for aforementioned reasons).
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