s2000Junky

yeah, its getting pretty contradictory and confusing guys. So I'm just going to break it down for you all in simple terms. Lower, wider, stiffer , stickier rubber = better. All you need to strive for

ndogg

Limiting body roll or squat/dive and its affect on CG movement has such a minor affect on the overall weight transfer that its not really worth noting in the ranges we are talking about for an s2000.

The anti-roll bar increases weight transfer at the axle its on while reducing it at the opposite. Same as increasing spring rate at one axle.

robrob

Love the irony.

SakeBomb Garage

Totally agree! Best part of R&C forum is that we can have detailed technical analysis!

LeonV

I'm genuinely curious here...

s2000Junky

Thanks, I find a sense of humor important as well, wile keeping things in perspective

s2000Junky

Yes, but sometimes at the expense of 2 guys jerking each other off in the corner of the room wile everyone else is watching, getting blurry eyed and confused

Carry on

SakeBomb Garage

It's very counter intuitive I agree. The total load transfer for the vehicle is a function of lateral acceleration divided by AVERAGE track width. This means that increasing track width decreases the total load transfer that occurs. However, the distribution of where the load transfer occurs is based on the ratio of each axle's roll stiffness compared to the total vehicle roll stiffness. Roll stiffness is a function of the the each axle's single wheel bump stiffness and its track width. By increasing the track width you have increased the axle's roll stiffness. Assuming the same spring rates and anti-roll bars etc. the wider track width increases you roll stiffness and therefor your relative load transfer on that axle increases. The overall load transfer decreases but the portion of that load transfer on the wider axle increases so the balance of the car shifts to give the narrower axle more grip.

s2000Junky

However, when you increase the track width here through higher offset wheels which is the basis for this discussion, you are effectively lengthening the leverage arm of that single wheel, and therefore decreasing the effective spring rate, which also effects load transfer. We can go around in circles all day on the subject, but we are still only talk about a chassis with 1" of of bump travel and 2" of droop. So a lot of the sum of all the parts explored is still minimal at the end of the day and many of them cancel one another out.

SakeBomb Garage

Not quite actually. Offset does not effect the motion ratio. Again its counter intuitive but the offset just creates an overturning moment (positive or negative depending on the direction of offset) which is reacted as tension and compression loads in the control arms. It does not however effect the vertical load on the lower ball joint and therefor does not effect the motion ratio or vertical stiffness. If you were to keep the same wheels and increase track with control arms then you would be absolutely correct that it would cancel, in fact it would actually more than cancel because the motion ratio is squared in the vertical stiffness equation but the vertical stiffness is only first order in the roll stiffness equations.

That said I generally agree that the bias shift is going to be small, but I think its important for people to realize it will be in the opposite way than they might expect. We just don't want people to spend a lot of money on an investment like wheels just to make a problem worse.