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M3 Castor Bushes
Posted: Tue Oct 23, 2012 4:41 am
by poolnoodle
Hi All,
The chromie needs new castor bushes and I have read all about the benefits of M3 eccentric type. I can get a OEM pair for less that US$50 from Pelican.
My local BMW Autohaus is going to fit them for me - any dramas to expect?
Will they fit ALL e30s?
Will I need a wheel alignment once fitted?
TIA
Neal
Re: M3 Castor Bushes
Posted: Tue Oct 23, 2012 5:02 am
by mark_i
Hi Neal
the offset bushes work with all e30... i got them on my touring and 2-door.
both feel so much better in terms of precise steering.
Re: M3 Castor Bushes
Posted: Tue Oct 23, 2012 6:47 am
by daimlerman
Make sure that they line the bush up correctly with it's housing,the aim is to move the base of the wheel out and a little forward.
Yes,have the tracking checked and adjusted as required.
You may also need to adjust the fit of the front plastic underpanel to stop the tyres catching on full lock as well.
Advantages are noticable,I ran two E30's side by side once,one with eccentric front bushes and one with concentric,even 'er indoors noticed that the eccentric fitted car 'steered better'....

Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 11:05 am
by poolnoodle
Thanks guys - sounds like the way to go

Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 11:11 am
by Alex
Only downside is that on full lock the tyre will rub on the inner arch plastic splash guard slightly.
Not sure if it would do the same on a pre facelift
Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 11:56 am
by Demlotcrew
daimlerman wrote:Make sure that they line the bush up correctly with it's housing,the aim is to move the base of the wheel out and a little forward.
Yes,have the tracking checked and adjusted as required.
You may also need to adjust the fit of the front plastic underpanel to stop the tyres catching on full lock as well.
Advantages are noticable,I ran two E30's side by side once,one with eccentric front bushes and one with concentric,even 'er indoors noticed that the eccentric fitted car 'steered better'....

They wont move the base out or alter the track width only castor angle.
Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 12:03 pm
by steve_k
Demlot, what would the effect on the handling be if you were to use the m3 eccentric bushes with the offset top mounts??
I only ask as I am looking at using both of these.
OP sorry for the hijack.
Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 12:26 pm
by Demlotcrew
Bushes cause castor change, top mounts cause camber change, it really does depend on what you are trying to achieve, for a track car both will only result in better handling
Dont forget, the amount of -ve camber thats needed is totally proportional to the roll of the car. What that means is, if you have a boat then no top mount I know off will neutralise the effects.
Andrew
Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 1:01 pm
by steve_k
Well i'm aiming for a cross between a road car (mainly) & a track car.
i'm going back to using coilovers (F & R) in the new year & i'm currently using a 24mm fr ARB & A 18mm r ARB.
I ain't interested in outright topspeed just want a car that handles the best it can.
Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 1:05 pm
by Demlotcrew
I would not advise you run large -ve camber settings on the front, you don't want to loose front end grip on the road (even though underteer is easier to correct than oversteer) during hard braking. Just set the car up for road and enjoy it on track. You cant have both sadly.
Andrew
Re: M3 Castor Bushes
Posted: Fri Oct 26, 2012 3:05 pm
by steve_k
No worries Andrew thanks for the advise

Re: M3 Castor Bushes
Posted: Sat Nov 24, 2012 8:45 pm
by steve_k
Demlotcrew wrote:I would not advise you run large -ve camber settings on the front, you don't want to loose front end grip on the road (even though underteer is easier to correct than oversteer) during hard braking. Just set the car up for road and enjoy it on track. You cant have both sadly.
Andrew
well i took your advise (in a way) & have now got a set of m3 eccentric bushes & also refitted my eibach adjustable top mounts,
at least now when/if i take it to a track day i can set it up for -ve camber for handling & when i've finished i can set the front end back to standard camber for the drive home.
Re: M3 Castor Bushes
Posted: Sat Nov 24, 2012 9:15 pm
by capri_rob
Alex wrote:Only downside is that on full lock the tyre will rub on the inner arch plastic splash guard slightly.
Not sure if it would do the same on a pre facelift
The splashguards are adjustable - on max adjustment no rubbing

Re: M3 Castor Bushes
Posted: Mon Dec 03, 2012 3:38 am
by poolnoodle
Having the bushes fitted tomorrow and wondering what is involved here:
You may also need to adjust the fit of the front plastic underpanel to stop the tyres catching on full lock as well
The car runs 16x7.5" wheels, lowered on Eibach Pro Kit
Re: M3 Castor Bushes
Posted: Mon Dec 03, 2012 10:20 am
by daimlerman
If you examine the plastic panel's mounts,you will see that they are mounted by those black plastic 10mm nuts onto welded studs.The plastic panels all have slots instead of holes to allow for adjustment...so slacken off and pull 'em about until the wheels clear the panels on full lock.
The tyres rubbing on the plastic bits is not a problem for MoT in the UK,no idea if you lot who walk on your heads will have an issue,though!
Re: M3 Castor Bushes
Posted: Fri Dec 07, 2012 1:09 am
by poolnoodle
No MoT inspection around these parts - pay the fee you get to drive it so long as the boys in blue don't catch you
Hopefully get the car back today so will take a closer look.
Re: M3 Castor Bushes
Posted: Sun Dec 09, 2012 4:38 pm
by HairyScreech
Your ride height will have an effect on how much static camber you need as well, as the angle of the lower wishbone is important, it dictates the camber change in roll and bump.
For an e30 around 30-40mm drop from standard height (not mtech) around -1.5 to -2.5 degrees seems to be a good point to aim for on the front for general day to day depravity and some fast work, seems pretty livable for both if you stick around there.
Seems to be true for the e36 compacts as well.
40mm drop with eccentric bushes gives about -2 to -2.5 front camber and a few degrees extra castor, tyre wear is reasonable, grip is reasonable and feedback is excellent.
One thing to remember is track days are not timed races, its far better to have something half a second slower on track that is more fun and easier to drive than something set up for ultimate grip that snatchy and uncomfortable.
Re: M3 Castor Bushes
Posted: Mon Dec 17, 2012 10:36 pm
by poolnoodle
M3 bushes now fitted and makes a nice improvement - particular higher speed / sweeping corners. Car feels more planted and steering more responsive.
Have noted that low speed (ie parking, etc) is slightly heavier. Is this normal?
Had no issue with tyres rubbing inner guards.
Re: M3 Castor Bushes
Posted: Wed Dec 19, 2012 12:20 am
by HairyScreech
Normal on all 3 accounts, some cars catch some don't, I think its down to splash guard adjustment and e30 vs e36 rack.