Geosetup before or after new tyres

I want to get a full geo setup done but also need new front tyres in the next 2-3k miles. Will it make a difference or should I wait and get new tyres and geo at the sametime?

If you get the same size, i don't see why it should make a difference

I don't really know how the geo setup is done and I have tyre wear on the edges of the tyres, didn't know if that would effect it at all.

do it once you have the new tyres. Every make of tyre is different and has a difference footprint on the road. A 265 tyre from Bridgestone will be different to a 265 from Goodyear.

Wear on the tyres would also be a factor.

Best wait until the new tyres are on.

Geo is referenced to the wheel rims or hubs, so the tyres are irrelevant so long as you don't change sizes when renewing.

Geo is referenced to the wheel rims or hubs, so the tyres are irrelevant so long as you don't change sizes when renewing.

But surely every make of tyre is a different size? My Bridgestone S-02 265 x 35 x 18 tyres are much wider than the old Continentals 265 x 35 x 18s? And the geo is done with the car sitting on the tyres so any adverse wear on the inner edge will make them lean even further in making the wheel angle wrong? On brand new tyres it would be true, but tyres that are already worn compared to ones that are not would give different results?

The tyres make no difference to how the geo ends up. When new ones are fitted all will be well.

Just to check on this, you can have a geosetup done on your car as standard right? you don't need to have adjustable suspension?

There's a lot of adjustability in the stock suspension, adding dampers with adjustable spring platforms just adds the ability to alter the ride height. You can do this with the Bilsteins, but it means machining new locating grooves for the platform circlips, and they can only be adjusted OFF the car.

Thats fine, just wanted to make sure there is a lot of adjusting capability on stock (or with standard Bilsteins) as my car is going in for new tyres, bilsteins fitted, and ge setup in the morning. Just didn't want to be paying for something that couldn't actually be done I will get a print out too.

But surely every make of tyre is a different size? My Bridgestone S-02 265 x 35 x 18 tyres are much wider than the old Continentals 265 x 35 x 18s? And the geo is done with the car sitting on the tyres so any adverse wear on the inner edge will make them lean even further in making the wheel angle wrong? On brand new tyres it would be true, but tyres that are already worn compared to ones that are not would give different results?

The overall proportions of two tyres of the same size should be the same. However the actual shape of the tyres can cary. For example, if two tyres of the same size from different manufacturers (tyre a and b) have different sidewall constructions then it's quite possible that tyre a will bulge more than tyre b under the weight of the car and become wider.

The stiffness of the construction and compound of the carcass and tread can also have an effect on several features. For example, if the carcass is softer on tyre a, then if the car has negative camber, the centre of the contact patch will move outwards. This movement relative to the king pin incidence can have an effect on the steering centering forces. Also moving the centre of the contact patch OB has the effect of reducing the roll centre of the car (If the roll centre is above ground, otherwise it will raise it).

The difference between a new and worn tyre (unless really extreme) will be negligible.

Hope that helps to clear it up!

The overall proportions of two tyres of the same size should be the same. However the actual shape of the tyres can cary. For example, if two tyres of the same size from different manufacturers (tyre a and b) have different sidewall constructions then it's quite possible that tyre a will bulge more than tyre b under the weight of the car and become wider.

The stiffness of the construction and compound of the carcass and tread can also have an effect on several features. For example, if the carcass is softer on tyre a, then if the car has negative camber, the centre of the contact patch will move outwards. This movement relative to the king pin incidence can have an effect on the steering centering forces. Also moving the centre of the contact patch OB has the effect of reducing the roll centre of the car (If the roll centre is above ground, otherwise it will raise it).

 

The difference between a new and worn tyre (unless really extreme) will be negligible.

 

Hope that helps to clear it up!

I'm not intelligent to understand that. Gone way over my head.

If your not confused then you clearly don't understand the situation.

I'm not intelligent to understand that. Gone way over my head.

 

If your not confused then you clearly don't understand the situation.

I would draw some diagrams but I'm rubbish at paint!

Basically what I'm saying is how soft or hard a tyres' construction is will have some effects on:-

a) how the tyre looks (explaining why JB may have been seeing differences in the apparent width of the tyre)

b) the dynamics of the cars suspension. The static geometry of the suspension won't change as per CW's post though.

Any better?

Basically, get a geosetup with the make of tyres you like and then stick to that make. Doesn't matter if they are new or old as wear won't make that much difference. Right?