Ride Heights - Page 3

s.mac · 28-02-2011, 10:01 PM

Tom posted this sometime ago for a standard reference

Quote:

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 · 28-02-2011, 10:43 PM

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** · 28-02-2011, 11:04 PM

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 · 28-02-2011, 11:10 PM

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 · 28-02-2011, 11:23 PM

Quote:

Originally Posted by NZ_M3

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** · 28-02-2011, 11:31 PM

Quote:

Originally Posted by 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.

Feck me you are dangerous

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

**glendog74** · 28-02-2011, 11:33 PM

Quote:

Originally Posted by shimmy

Feck me you are dangerous

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

titan · 01-03-2011, 12:17 AM

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** · 01-03-2011, 12:22 AM

Quote:

Originally Posted by shimmy

Feck me you are dangerous

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

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

and keep an eye on tyre pressures. I run at least 28psi cold and usually take quite a bit more out once hot.

**AlexGTT** · 01-03-2011, 12:25 AM

Quote:

Originally Posted by 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 ?

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.

28-02-2011, 11:04 PM	#23
shimmy CSL Register Uber-poster! Join Date: Apr 2008 Location: Uk Posts: 14,646 Casino cash: $43909	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? __________________ .

28-02-2011, 10:43 PM	#22
titan S5 - Full Throttle Join Date: Aug 2010 Posts: 268 Casino cash: $1363	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.

28-02-2011, 11:10 PM	#24
titan S5 - Full Throttle Join Date: Aug 2010 Posts: 268 Casino cash: $1363	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.

01-03-2011, 12:17 AM	#28
titan S5 - Full Throttle Join Date: Aug 2010 Posts: 268 Casino cash: $1363	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 ?