Rear wheel alignment on lowered cars

S

Spetz

Well-Known Member
Hi guys,

I have a CE coupe that I use on the track and needing to do a wheel alignment on it.

The last time it was aligned at the rear it had 1mm toe in and -2 degrees camber.

What I want is about -1 to -1.5 degrees camber and a tiny bit of toe out.

Are these settings possible on a lowered car (rear LCA are about parallel to the ground) or would I need to get those camber/toe arms from Hardrace to get into the settings I want?
 
You have about 3 degrees camber to work with when stock, so you should be fine getting the specs you want out of the stock setup
 
You should be able to get those settings fairly easily. I'll be interested to hear your feedback on these settings. Did you end up with the MCA coil overs.
 
Thanks guys. I guess I'll aim for those settings and if not I'll get the arms as I prefer to keep as many OEM parts as possible.

@frosty7
Yes I ended up going for the MCA Reds in the end. They were shipped out today so should have them shortly.
Ended up going for 9kg springs all round but have "pre-bought" another set of springs which I will get after seeing how these go and whether I need to go stiffer/softer.
I don't expect to be back at the track for a couple of months at a minimum though as it's almost 40 degrees daily over there
 
that alignment can be achieve.
i used to run -1.5 to -2 deg rear camber and 0.5 to 1mm total toe out rear when i had a slow car.
When the car is real quick and has lots of grip zero rear toe is more manageable.
rear toe out on a real quick car can go pear shaped real quick.

What you want is easily achieved with stock trailing arm bushings.
more solid type bushing are harder to dial in but you should achieve it.
Let me know what trailing arm bush you run and I can give more details.
 
@Hens
The car isn't too quick (I suspect around high 13 second 400m run) but I use it at Winton which is fairly tight and technical so I think a bit of toe out is the way to go.

The rear bushes are all SuperPro items including the dogbone bushes except the spherical bearings which remain OEM. The small dogbone arms are from an FTO (same length but stronger).

With -2 degrees camber at the rear I can see from the wear of the tyres that the outer edges don't get any contact
 
With toe out you may not get a better contact patch for the tyre. This is still worth a try and like I said before, I'll be interested to see your impressions. Front toe is easy at the track but I've always been hesitant to adjust the rear toe half way through a day.
 
DIY alignment adjustment?

Unfortunately I won't be able to give a back to back comparison though as I've changed coilovers along with the alignment settings since the last time the car was at the track.

I've just been reading that a bit of rear toe out will help with rotation which I think for a FWD is important on a tight track.
The contact patch increase was from running less negative camber rather than the toe settings
 
Im an advocate of the OEM rose joint spherical stuff. You cant beat it.
the superpro rear trailing arm bush will prevent the end of the adjustment being dialed in. Because it doesnt flex in the required axis that is a compromise and there will be some binding.
From memory if you try to run too little camber you run into range adjustment in toe.

If you just commute with the car half the time -2deg camber on any end of the vehicle is pointless. If you want to go fast around corners it is a compromise.
Most setups wont need more than -1.5deg rear camber and around -2deg at most.
it depends on the available grip and application.
you cant just say with toe out you wont get better contact patch.
toe out at the rear is for only for ONE reason., that is to promote rotation.
say in a hillclimb/autocross/motorkhana i could recommend rear toe out. the amount depends on the driver.
with too much on a road car, all you need to do is come in too hot, lift and/or get on the brakes and the arse end will hang loose.

With my previous slower setups on run maybe 0.7mm toe out total. You have big balls. Ive never run more than 1mm total rear toe out
I ran rear toe out for many years. But it for the more experienced driver. A notice driven sometime couldnt catch or respond to oversteer let alone snap oversteer.
On my fast car its a rocketship and Im scared of it entering corners flat out. I have -2deg rear and zero toe. You cant fail with zero toe. OEM setting is toe in since it has to cater for most drivers and snap oversteering around a roundabout wont look good on the news.

And this thread is about rear aligment so I wont go off topic.
 
The front adjustment is easy at the track just crack the jam nut and give it quarter to half a turn remembering to lengthen or shorten for toe out or toe-in. Just don't go silly and make huge adjustments.
 
The only car Ive had to put toe out on was a Mini. With toe in on the rear it was nu-drivable, plow under-steer. 1mm toe out transformed the car, but on the Mirage we run 1/2 mm toe in and it sticks like glue.
 
Thanks Zipper.
I may run 0 to a tiny bit of toe out only because Winton track has some technical corners which are slowing me down
 
Hi guys,

Just as an update to this, I took the car for a wheel alignment today.

At about 40mm lower than standard the rear settings are -1.3X camber and 2mm total toe out at the rear.
The aligner told me camber was not an issue and I could go more (not that I wanted to but I will check tyre temps + wear pattern) but that was max toe out (it may be a bit too much but I will dial it down if need be).

So overall answer to my original question is that there was no need for adjustable arms to get the alignment I wanted.
This is running superpro bushes everywhere but where there were factory rose joints on FTO lower control and dogbone arms

For reference the front received -2.5x camber and 1mm toe out.

I drove the car for the first time on the MCA reds and they felt good.
at 9kg/9kg over speed bumps it was really noticeable that the rear was stiffer than the front so I would not recommend an even spring rate all round for a street car as it feels odd.
The valving felt nice and smooth overall (on full soft).

Being a track only car though stiffer rear springs should minimize understeer especially under throttle since there should not be much rear squat/front lift.
I also bought 4 springs from MCA that I will receive after testing the car and letting them know how it handled to figure out what spring rates to go for.
 
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