Steering Alignment (with Correct Data in Post 1) - Page 6 - Alfa Romeo Forum
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To what extent does the rear camber effect things? Tyres wear dead flat on the back. Also the back was empty, half a tank of juice, should that be taken into consideration?
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Well here's my view (after waving my hands about to work out what direction the car would have been going)

You have some crabbing from the rear end unbalance which is translating to the front and being magnified.

So the rear end is self aligning causing the car to move to the off side.
To counter this you have been turning the steering slightly to the right.
This means the nearside front (which also has more weight on it in heavy cambered roads) is probably pointing straight ahead.
And the off side wheel is pointing to the right and is dragging its inside edge.

I did the hand waving and went back to your original post which confirmed it was the off side front that was in trouble!

The overall point is that you would get away with it at zero but not with what you have (which is now worse since the change)

I would get the back balanced and then set the front to zero.

Last edited by Old Engineer; 06-02-12 at 18:27. Reason: Spelling
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Great, That makes sense, so its the inbalance of the rear tracking? Any views on the rear camber?
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Just learned this morning that Monza Sport, my local Alfa Romeo garage has 4 wheel laser alignment, I'll take the car there. A garage I can trust.
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Totally concur with OE (also determined by hand waving - is that scientific enough?)

I haven't seen this type of print from Hunter equipment before and the types I have seen would have shown more clearly the effect that the uneven rear toe is having on "thrust angle" and how that creates crabbing with the need for correcting that on the steering and the drag caused on the offside front.

It is up to you whether you have the front toe set to the new -2 or zero but whichever you choose please tell Monza what you want and tell them you want the print. They may know to do that but many garages will say they have the latest settings as they are loaded automatically; I have found that very often that is not true!

Hopefully Monza will know the revised setting but a polite chat will ensure you get what you want and, if you don't get that, you can have it put right for free if they get it wrong.
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I am a big fan of getting the thrust angle to zero, and always do this on my competition car; however to put things in perspective, a thrust angle of 1 minute (1/60th of a degree), translates roughly to the rear being 0.72 mm out of line relative to the front
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If my maths are accurate and assuming the rear axle is 2.5m from the front that still equates to the front wheel having been dragged sideways for 4km in every 10,000km.

If the rear axle is 2m from the front then 4km increases to 5km in 10,000km.

However your first statement is the important one - you believe in having it done; everyone who has had this done to their car has had massive improvement in tyre life and a car that feels much more stable. So it's not just about theory it's about real life results.
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Quote:
Originally Posted by kandlbarrett View Post
If my maths are accurate and assuming the rear axle is 2.5m from the front that still equates to the front wheel having been dragged sideways for 4km in every 10,000km.

If the rear axle is 2m from the front then 4km increases to 5km in 10,000km.

However your first statement is the important one - you believe in having it done; everyone who has had this done to their car has had massive improvement in tyre life and a car that feels much more stable. So it's not just about theory it's about real life results.
It is actually a bit less, circa 2.8 and is independent of wheelbase. Whether a small thrust angle will cause tyre wear is a moot point, as the front wheels are also turned slightly to make the car run straight - so the rears are not dragged, just slightly offset.

As far as I am concerned setting the thrust angle is only part of competition preparation which includes corner weighting and minimising bump steer - on most road cars this can not be eliminated, but at least should be the same for each front wheel. The upshot of all of this is despite running quite high camber settings, the road tyres on that car wear amazingly well!
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Just re-reading this, and thought a comparison of the figures that car came with vs. where it is now might be instructive.

As delivered (I had the dealership measure it prior to delivery after reading the Tyre Wear Issue thread):
Front Camber:
LF -56' RF -1 degree 20' - should be -26' +/- 18'
Front Toe:
LF -10' RF -10' - should be -08' +/- 04'

Rear Camber:
LR -52' RR -39' - should be -58' +/- 18'
Rear Toe:
LR 14' RR 17' - should be 13' +/- 07'

This meant - according to the figures they had from ARUK - that while the Toe was within spec, the camber on 3 of the wheels was outside the maximum permissible values.

After many trips back to 'fix' it (including replacing suspension components at their expense), it wasn't until I threatened to reject it that they got someone from ARUK to come out to inspect it. It turned out that the dealership did not have the 'correct' values for a 3.2 S, and the car was then set to:

Front Camber:
LF -1 degree 17' RF -1 degree 14'
Front Toe:
LF -0.3mm RF -0.3mm (yes, I know, different units but it seems that this is what Corghi equipment uses)
Rear Camber:
LR -1 degree 11' RR -44' (didn't bother adjusting it I'm thinking)
Rear Toe:
LR +2.2mm RR +1.0mm (didn't touch that one either then!)

I gave up at that point and took it to a local independent garage that set the front Toe to parallel, the rear camber to -1 degree, and the rear toe to +13'.

From this I learnt that ARUK technical department are not terribly well organised, and that the dealership's workshop is one to avoid.

I think I'll treat myself to a trip to see Peter Cambridge at Easter...
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I checked mine yesterday and the front tyres have only done about 4K but are showing considerable wear on the inner edge, nothing illegal yet but i intend to get it sorted.

What should i tell the alignment people?

I still find the whole minutes and degrees thing a little confusing, especially if camber is taken into consideration as well.
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What should i tell the alignment people?
For the front, VERY simple: set it to 0mm toe.

For the rear camber and rear toe, the std settings are fine.

If they are willing to spend time equalising front camber, that can be done by moving the subframe sideways slightly.
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Quote:
Originally Posted by David C View Post
For the front, VERY simple: set it to 0mm toe.

For the rear camber and rear toe, the std settings are fine.

If they are willing to spend time equalising front camber, that can be done by moving the subframe sideways slightly.
Thank you David

Im going to get it booked in here http://allcartyres.com/page.php?id=82

Last edited by GhostyDog; 12-02-12 at 21:33.
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Quote:
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For the front, VERY simple: set it to 0mm toe.

For the rear camber and rear toe, the std settings are fine.

If they are willing to spend time equalising front camber, that can be done by moving the subframe sideways slightly.
My car's in at Heath Rd Garage this week. I've asked them if they can sort the tracking and mentioned that the standard settings are bobbins.

Should I do as stated in your qoute Mr C? The whole thing just baffles me.

Front toe is parrallel? Is that the same for front camber too?

Rear is ??

Should I just take this in?

http://www.alfaowner.com/Forum/attac...alignment2.jpg Courtesy of Old Engineer.

I'm assuming that the camber from the LHS to RHS is for some reason like road camber or something?

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I'm assuming that the camber from the LHS to RHS is for some reason like road camber or something?
No, it is purely because they haven't bothered to adjust it...!

Rear camber is adjustable, so no excuse for not doing that.
Front camber can't be adjusted, but it can be equalised by moving the front subframe sideways (the subframe isn't pinned in an exact location, so there is movement available once the bolts are loosened).
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Please tell me you're kidding...
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Please tell me you're kidding...
About what?
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He's not kidding!
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Crikey!

So I should be asking for the front wheels parrallel and get them to sort out the camber as best as possible via the old 'subframe waggle'.

Back end should be toe'd 13 minutes 'open' and the camber SHOULD be???

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Back end should be toe'd 13 minutes 'open' and the camber SHOULD be???
Rear should be set to toe IN 11’ +/- 7’ each side (total rear toe-in: 22’ 7’)
(the ’ symbol is minutes for anyone reading this that didn't know)
The rear camber –1 3’ 18’ for the Ti
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Wow - how confused am I?!

I can't even begin to understand this stuff.

So long as the chap working on the wheel alignment does as follows, I should be ok?

Front wheels parrallel and get the camber as best (equal) as possible via the subframe adjustment.

Rear should be set to toe IN 11’ +/- 7’ each side (total rear toe-in: 22’ 7’)
The rear camber –1 3’ 18’
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Rear toe at 22' +7' = 29', which is way too much. Personally I would go for 15- 20' combined toe-in at the rear - this is a good default setting for most FWD road cars. I have set my Lusso at this (17"), and tyre wear is perfect.
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Quote:
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Rear toe at 22' +7' = 29', which is way too much. Personally I would go for 15- 20' combined toe-in at the rear - this is a good default setting for most FWD road cars. I have set my Lusso at this (17"), and tyre wear is perfect.
I'll ask for 18-22' combined toe-in at the rear then
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Well got mine done and its far better, pretty much everything was red to begin with

Before

Front

Camber -1 19' -1 03'
Caster 3 24' 3 42'
Toe -0 10' -0 04'

Rear was out on camber

Now front is good for toe but caster and camber show as still being out, Every time they nudged the subframe it shifted back when tighteneing the bolts.

Thrust angle is 0 00

Ive found road noise is seriously reduced at the front and rolling resistance seems less, steering feels a bit more responsive, all in very happywiththe changes especially if it means my tyres will live longer.


Nero Fuoco 147 Lusso - Bianco Nuvola 147 GTA - Carbonio Brera SV - Azzurro Le Mans GT 1600 Junior
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Quote:
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Rear toe at 22' +7' = 29', which is way too much. Personally I would go for 15- 20' combined toe-in at the rear - this is a good default setting for most FWD road cars. I have set my Lusso at this (17"), and tyre wear is perfect.
In my Brera Owner's Manual it suggests 13' +/- 7' giving 26' + 7' = 33'...

(Front says -8' +/- 4')
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Ghostydog: did you watch then do the adjustments? All they need is a second pair of hands. One holding the frame in place with the bar and the second tightening the bolts. Pinch them up a bit at a time and it should stay in the right position.
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