BC Coilover Install Question

TurboTom · 08-01-2022, 11:22 PM

Question for you smart people out there.

I'm installing BC coilovers on my e90 (2011 N55). The kit comes with adjustable endlinks. What's the best way to get the adjustment right on those, keeping in mind my car is about 1" lower than original height. Also worth noting, I'm using a lift so I have all four corners off the ground and can bring one to ride hight at a time.

With my limited understanding of how these things work I'm thinking of two options.

1) Match OEM endlink length on each side. I did this temporarily but think my other option is better.

2) Remove the endlinks and drive the car on to a set of ramps. Crawl under and install the endlinks under no tension in this position.

Is it worth changing from oem length to #2 above as a starting point before getting an alignment?

On another note... Did you all install a gasket between the hat and the strut mount in the front? There's a paper gasket on the OEM assembly. Mine were trash if I need them, I have to go back and add them.

Thanks!

Tambohamilton · 08-02-2022, 06:46 AM

You can calculate the length they should be; OE length + (ride height drop * 0.9). So something like 10"+(1"*0.9)=10.9"....those measurements are made up though. That should get you close enough that it doesn't matter.

The paper gasket is to prevent creaking. You can make your own out of gasket paper pretty easily. Doesn't have to be anything fancy.

TurboTom · 08-02-2022, 08:17 AM

Quote:

Originally Posted by Tambohamilton

You can calculate the length they should be; OE length + (ride height drop * 0.9). So something like 10"+(1"*0.9)=10.9"....those measurements are made up though. That should get you close enough that it doesn't matter.

The paper gasket is to prevent creaking. You can make your own out of gasket paper pretty easily. Doesn't have to be anything fancy.

Interesting, but I’m not sure how to calculate how far I’ve dropped from OEM ride height. Shouldn’t the endlinks be under no tension at a rest (and at ride height)? It would seem installing them with no tension and with the car on the ground would be the most accurate way to get them in there under no tension.

Blau · 08-02-2022, 08:53 AM

Quote:

Originally Posted by TurboTom

Interesting, but I’m not sure how to calculate how far I’ve dropped from OEM ride height. Shouldn’t the endlinks be under no tension at a rest (and at ride height)? It would seem installing them with no tension and with the car on the ground would be the most accurate way to get them in there under no tension.

Have your alignment shop do this part for you. I'm sure they'd be happy to.

Tambohamilton · 08-02-2022, 04:24 PM

Quote:

Originally Posted by TurboTom

Interesting, but I’m not sure how to calculate how far I’ve dropped from OEM ride height. Shouldn’t the endlinks be under no tension at a rest (and at ride height)? It would seem installing them with no tension and with the car on the ground would be the most accurate way to get them in there under no tension.

There are specs for ride height. The links should be under no tension, but can't guarantee your sway will be sitting in the correct orientation.

TurboTom · 08-02-2022, 08:36 PM

Quote:

Originally Posted by Tambohamilton

There are specs for ride height. The links should be under no tension, but can't guarantee your sway will be sitting in the correct orientation.

I guess I'll see if the alignment shop can take care of it then. I have an identical car with stock suspension so my plan was to assess the angle of the sway bar on the OEM setup then adjust the BC end link to match but it sounds like the alignment shop may be able to get a more precise adjustment.

One thing I did notice is that just to match OEM end link length, the BC end links were almost maxed out. They had maybe 2x bolt diameter in thread length left. I was surprised because most people will be lowering their car and would be more likely to need longer than OEM end links.

Tambohamilton · 08-03-2022, 03:23 AM

Quote:

Originally Posted by TurboTom

I guess I'll see if the alignment shop can take care of it then. I have an identical car with stock suspension so my plan was to assess the angle of the sway bar on the OEM setup then adjust the BC end link to match but it sounds like the alignment shop may be able to get a more precise adjustment.

One thing I did notice is that just to match OEM end link length, the BC end links were almost maxed out. They had maybe 2x bolt diameter in thread length left. I was surprised because most people will be lowering their car and would be more likely to need longer than OEM end links.

You have a car to measure stock ride height? Just take the 'before' measurement from that, then. And use the formula I posted.

Does sound pretty odd that the links can't be run significantly longer than stock. You may just have to run them as long as they will safely go.

whyzee125 · 08-04-2022, 12:50 AM

They don't have to end up being the exact same height as stock, just close will be more than adequate. The important thing is to make sure that there is no preload on the bar.

What I do is adjust all 4 corners of the car to where I want it with no end links in place and ensure the car is level. Put the front on even-height ramps and install one end link and tighten it.

Then, move to the other side and adjust the end link so it can slide right in with no force, so you'll have no preload.

There might be better ways to do it but that's how I do it and it works great for me.

08-01-2022, 11:22 PM	#1
TurboTom Private 24 Rep 83 Posts Drives: 2013 135i DCT Join Date: Aug 2019 Location: Florida iTrader: (1)	BC Coilover Install Question Question for you smart people out there. I'm installing BC coilovers on my e90 (2011 N55). The kit comes with adjustable endlinks. What's the best way to get the adjustment right on those, keeping in mind my car is about 1" lower than original height. Also worth noting, I'm using a lift so I have all four corners off the ground and can bring one to ride hight at a time. With my limited understanding of how these things work I'm thinking of two options. 1) Match OEM endlink length on each side. I did this temporarily but think my other option is better. 2) Remove the endlinks and drive the car on to a set of ramps. Crawl under and install the endlinks under no tension in this position. Is it worth changing from oem length to #2 above as a starting point before getting an alignment? On another note... Did you all install a gasket between the hat and the strut mount in the front? There's a paper gasket on the OEM assembly. Mine were trash if I need them, I have to go back and add them. Thanks!
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08-04-2022, 12:50 AM	#8
whyzee125 Brigadier General 1679 Rep 3,645 Posts Drives: Dinan stage 2 335i Join Date: Jul 2014 Location: Chattanooga Tn iTrader: (0)	They don't have to end up being the exact same height as stock, just close will be more than adequate. The important thing is to make sure that there is no preload on the bar. What I do is adjust all 4 corners of the car to where I want it with no end links in place and ensure the car is level. Put the front on even-height ramps and install one end link and tighten it. Then, move to the other side and adjust the end link so it can slide right in with no force, so you'll have no preload. There might be better ways to do it but that's how I do it and it works great for me.
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08-02-2022, 06:46 AM	#2
Tambohamilton Brigadier General 3058 Rep 3,910 Posts Drives: E91 330d Join Date: Apr 2019 Location: Herefordshire iTrader: (0)	You can calculate the length they should be; OE length + (ride height drop * 0.9). So something like 10"+(1"*0.9)=10.9"....those measurements are made up though. That should get you close enough that it doesn't matter. The paper gasket is to prevent creaking. You can make your own out of gasket paper pretty easily. Doesn't have to be anything fancy.
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