camber, caster, toe in and ride height.

[bordseye]

took the opportunity to have the wheel alignment checked by the local tyre garage - the Hunter set up. Sure they arent a specialist but they do have the latest kit, and a conscientious guy operating it. I watched the whole process.

The back end of the car is now bang on but the front is still out a bit on caster and camber albeit far closer than it was. I know from the PPI that the front ride height is a bit low and this does affect caster which is 6deg 19 front left and 6 deg 4 front right - should be 6 deg both +/- 0.1 so the right is within tolerance. Both cambers are out - both a bit too negative, the left worse than the right.

Is there anyone on the forum who understand how these 4 measurements interact? The car steers and tracks fine and definitely has more bite going into corners than it had but I am wondering what would be the effect of me correcting the front ride height at home

Please dont tell me I should go to a specialist - there isnt one anywhere near here and I took advantage of a chance to use this non specialist outfit.

[E-bmw]

IIRC the slightly increased castor will increase the effect of "self centring" of the steering wheel when coming off lock and the amount will not be significant based on your readings.

The increase in negative camber will improve turn-in so you are right to say that & more noticeably reduce understeer.

Others may know more details, but I certainly wouldn't be worried by that.

If you do LOTS of motorway miles you may notice increased tyre wear on the tyre inner edges.

[tapkaJohnD]

This is done every time a race car comes back in after test laps, and the simulator boys spend HOURS fiddling with it. So have a look at this 'lecture' from one of their sites:
https://www.projectcarsgame.com/the_insiders_guide...

If you understand things better, visually, have a look at this page, especially the second half, "Can Lowering The Vehicle Change The Camber?"
https://www.oponeo.co.uk/tyre-article/camber-under...
and from there, this pic



Hope that helps
John

[GreenV8S]

bordseye said:

both a bit too negative, the left worse than the right.

Are you trying to achieve some sort of handling / performance setup, or just get a road car set up per manufacturers spec?

Settings to maximise performance will not be ideal for normal road use.

[bordseye]

just to get manufacturers spec.

[GreenV8S]

Lowering the car will typically introduce negative camber and also affect the roll center height, probably lowering it - which is not ideal. In a perfect world ride height changes wouldn't affect toe-in settings, but if you do plan to adjust the ride height then check all the other settings afterwards.

To know whether it's worth addressing it you need to know how far out it is. The castor figures, for example, seem to me to be close enough to ignore.

Edited by GreenV8S on Friday 30th August 01:06

[bordseye]

I dont think the car has been lowered by a previous owner - had they done so, then IMO it would have been obviously lower which it isnt. I simply think it has "relaxed" a bit over its 16 year life.

I like things to be "right" and with camber on both wheels and caster on one being a lttle bit out of tolerance ...........

I'll have a fiddle with it this winter.

[SAS Tom]

You may find that the caster and camber aren’t adjustable. It also sounds like the settings aren’t that far off. There’s all sorts of factors that can make a difference and that trying to correct them are unlikely to make a huge difference but will cost a lot of money to do. An example would be if the car isn’t camber adjustable then it’s going to cost money to make it adjustable through fitting camber bolts, camber bushes, camber plates or coil overs etc.

Also bear in mind that the machines are that accurate that just lifting the car on the ramp then dropping it back down without touching it can change the readings even though no settings were changed.

If it drives straight and handles alright I’d ask the garage that did it what they think to the out of spec settings and see if they think it’s worth correcting. I doubt they will think it’s worth bothering.