Run flat tires

[ard]

Originally Posted by master1917

Ard, can you please clarify the 3 above. I thought I should specify the toe numbers of .02 only. Is camber and caster also adjustable on X5M E70? I have seen posts about camber on the fronts being not adjustable and greatly contributing to outside edge wear.

PS I am not knowledgeable on any of it as all this topic is new to me as I started kooking into it 2 days ago on my way from Florida when I noticed my fronts outside edges are disappearing so bear with me please...

Sure.

Caster is not really adjustable.

Camber can be 'adjusted' in the front with different control arms, so for all practical purposes it is set too. I dont recall if messing with the upper mount on the strut will get you anything.

Toe is adjustable front and rear

Camber is fully adjustable in the rear.

Here is a key:

yes, cambering a tire will create more 'pressure' on ne edge tor the other. This is conceptually easy to understasnd- 'the inner edge is wearing, that cause the wheel is cambered pushing that inner edge down'

WHAT IS NOT OBVIOUS is that 'toe' acts as a 'compounder': the tire is cambered, but then the toe acts to scrub that edge even more than if it had not been cambered.

Since we really have limits on camber- and in fact you DO want camber to help stabilize cornering- then back the toe down to almost zero. 0.01 or 0.02.

I have a track prepped 996TT, on which ive run some interesting alignments... but this can be corner balanced for pressure, and camber, caster and toe are all independently adjustable (as is shock compression and rebound)...the point being tat the E70 simply is not a race car, it doesnt have the adjustments a track car has, it doenst have the tires, suspension or get driven at track speeds. The silly "aggressive driver/freeway offramp" language that I have seen for years is simply a disservice to the majority of X5 drivers. VAST majority. Everyone wants to think they are a BMW race car driver. We arent. I mean shops will repeat all kinds of old wives tales they really truly believe: BMWs are set aggressive, just the way they are- they eat tires. or 'set it mid spec, BMW engineers do it on purpose...or the ol' 'gotta pay to play'...the list never ends.

I will come back to the fact that I give very specific numbers and do this for a reason and a rationale. To come here and say "ard is wrong", yet to offer up 'one size fits all ricerboi platitudes' about aggressive or performance alignments...and you cannot provide a SPECIFIC ALIGNMENT NUMBER SETTING on the E70 X5 to achieve this 'performance setting' is BS.

[master1917]

Originally Posted by ard

Sure.

Caster is not really adjustable.

Camber can be 'adjusted' in the front with different control arms, so for all practical purposes it is set too. I dont recall if messing with the upper mount on the strut will get you anything.

Toe is adjustable front and rear

Camber is fully adjustable in the rear.

Here is a key:

yes, cambering a tire will create more 'pressure' on ne edge tor the other. This is conceptually easy to understasnd- 'the inner edge is wearing, that cause the wheel is cambered pushing that inner edge down'

WHAT IS NOT OBVIOUS is that 'toe' acts as a 'compounder': the tire is cambered, but then the toe acts to scrub that edge even more than if it had not been cambered.

Since we really have limits on camber- and in fact you DO want camber to help stabilize cornering- then back the toe down to almost zero. 0.01 or 0.02.

I have a track prepped 996TT, on which ive run some interesting alignments... but this can be corner balanced for pressure, and camber, caster and toe are all independently adjustable (as is shock compression and rebound)...the point being tat the E70 simply is not a race car, it doesnt have the adjustments a track car has, it doenst have the tires, suspension or get driven at track speeds. The silly "aggressive driver/freeway offramp" language that I have seen for years is simply a disservice to the majority of X5 drivers. VAST majority. Everyone wants to think they are a BMW race car driver. We arent. I mean shops will repeat all kinds of old wives tales they really truly believe: BMWs are set aggressive, just the way they are- they eat tires. or 'set it mid spec, BMW engineers do it on purpose...or the ol' 'gotta pay to play'...the list never ends.

I will come back to the fact that I give very specific numbers and do this for a reason and a rationale. To come here and say "ard is wrong", yet to offer up 'one size fits all ricerboi platitudes' about aggressive or performance alignments...and you cannot provide a SPECIFIC ALIGNMENT NUMBER SETTING on the E70 X5 to achieve this 'performance setting' is BS.

Thanks ard, so now I am clear that for a longer tire life, the E70 X5M, the camber in the rear must be mid range of the specs and the toe for both front and rear must be at either +0.01 or +0.02. These values must be the same per axel but may differ between the front and rear axels like +0.01 upfront and +0.02 in the rear or the other way around.

PS I am surprised my fronts are gone before rears. Rears look great. Fronts are gone.