Ride Heights

[shimmy]

Cheers, thats useful. So I'm comparing apples with apples - from top of arch to wheel centre ?

I think that is the proper way to easier I but Simpsons measure top of arch to floor (which introduces two errors in wheels size and tyre size) so if you are running 640 to wheel centre you are driving a TRACTOR

Just measured and top of arch to wheels centre looks like 330F and 325R

[titan]

340F and 325R. Although thats a best guess at looking past the tape to the wheel centre, if I bend/follow the tape into the wheel centre you can add another 5mm.

Simpson set the camber at 1.5 and said that a little trick is to ignore the adjusters on the topmounts, but instead slacken the turret bolts and the play between outside and inside was equivalent to another degree (and also made a little toe-out). Not having a camber gauge I cannot say.

[daniel_csl]

2.5"-3" front camber is what you need:thumbs:

[shimmy]

2.5"-3" front camber is what you need:thumbs:

He will have -2.5 when top mounts are adjusted

You prob will want -3 or more for the correct camber on track Tyres depending on circuit but running more than -1.5 on road for long distances will knacker the insides

[shane@mbtech]

I set mine to -3.5* front on the inners of the turrets, then slacken off and move out to approx -2.5* on the outer of the turrets using the 3 13mm nuts. Takes 2 secs and saves tyre wear, although I used to forget and my tyres still worn perfectly even too.

As you say, moving the camber in takes the toe back to near 0, from the slight toe out I was running.

I never had any understeer issues either, I will try to dig out my spec sheets for my ride heights.

But as I said Lee, experiment and find what suits YOU. Thats what I did.

I tried simpsons Geo, but I actually prefered the way Chris set mine up, I was faster on Chris's setup too. Not taking anything away from The simpsons lads, because they know their onions. I just prefered a different set-up. I think Chris set my car up more aggressive than Simpsons did, and it suited me more.

[s.mac]

Tom posted this sometime ago for a standard reference

I just had my geo done today on the BMW Kinematic Diagnosis System (KDS) and the print out states the factory ride height spec as follows:

Measure from the bottom of the rim to the top of the wheel arch through the centre of the wheel:

Factory Spec:
Front Target: 607mm+/-10mm
Rear Target: 602mm+/-10mm

[titan]

I don't really use the car much apart from trackdays so running high camber isn't the same kind of issue as it would be for a daily driver.

Its a good point to find out what suits.

I've only ever gauged correct/incorrect camber by looking for wear on the sidewalls or specific areas on the contact patch, and ensuring that heat across the entire contact patch is more or less constant. After all, isn't the purpose of camber to ensure that when cornering the roll of the car just "corrects" the negative camber to ensure the tyre is then "flat" against the track surface? I believe stickier tyres esp slicks demand more camber because their grip is so much more, hence the roll of the car is so much more.

Interesting to know what happens in the wet though. Too much camber and surely you're running on the insides, therefore unable to get the grip required to force body roll onto the entireity of the tyre...so less camber in the wet ?

Currently I've got the hankook rs2s on the car.

[shimmy]

You should be able to feel the corner grip with more camber but otherwise pyro readings is by far the best way.

We did Snett last year with full pyro and actually wound the camber in on the right side of the car.

DONT FORGET TYRE PRESSURES, what you running hot?

[titan]

Thats another good question which I can't answer. I set tyres to 30 when cold, at oulton was doing about 5 to 7 laps in a session, doubt they got significantly hot but really should invest in a decent and quick gauge.

the gt2rs has a realtime pressure display on the dash !!

We looked into these last year:

http://www.tyresave.co.uk/smartire.html

but never bothered in the end.

[DuncanR]

Run the fronts too low and all you'll get is understeer

Absolutely spot on Tom ... Henk at Intrax will tell you this also. I hope all family and friends are ok out there Tom after recent events mate.

[shimmy]

Thats another good question which I can't answer. I set tyres to 30 when cold, at oulton was doing about 5 to 7 laps in a session, doubt they got significantly hot but really should invest in a decent and quick gauge.

the gt2rs has a realtime pressure display on the dash !!

We looked into these last year:

http://www.tyresave.co.uk/smartire.html

but never bothered in the end.

Feck me you are dangerous :thumbs:

Not sure on the weather but at 30 cold you could have got the Tyres up to 36 hot at the back I would guess, no wonder they felt a bit squirmy. Before you buy new Tyres and suspension you might wanna buy a pressure gauge :thumbs:

[glendog74]

Feck me you are dangerous :thumbs:

Not sure on the weather but at 30 cold you could have got the Tyres up to 36 hot at the back I would guess, no wonder they felt a bit squirmy. Before you buy new Tyres and suspension you might wanna buy a pressure gauge :thumbs:

:hahaha::hahaha::bigcry::hahaha:

[titan]

heh, shall I just give up ?

OK its a reasonably fair point but having played with tyre pressures in the past (albeit different cars) I can't say I've noticed a huge amount of difference.

In fairness I do check pressures in the summer as bone dry trackdays tend to heat things up nicely.

What pressures (hot) would you recommend ?

[AlexGTT]

Feck me you are dangerous :thumbs:

Not sure on the weather but at 30 cold you could have got the Tyres up to 36 hot at the back I would guess, no wonder they felt a bit squirmy. Before you buy new Tyres and suspension you might wanna buy a pressure gauge :thumbs:

:hahaha: Indeed.

Slightly lower ride height all round (Shimmy's measurements give you a decent start point), more camber (at least -3 front -1 rear), decent tyres :whistle: and keep an eye on tyre pressures. I run at least 28psi cold and usually take quite a bit more out once hot.

[AlexGTT]

heh, shall I just give up ?

OK its a reasonably fair point but having played with tyre pressures in the past (albeit different cars) I can't say I've noticed a huge amount of difference.

In fairness I do check pressures in the summer as bone dry trackdays tend to heat things up nicely.

What pressures (hot) would you recommend ?

Believe me, BIG difference on E46 M3/CSL. Cups are quite sensitive to pressures.

Hot I run 30ish front 32ish rear.

You will find you wear out the centre of the trye running Cups with pressures to high.