Alludc

didnt really think of this until last week. when I was running hoosiers id obviously change them at the track just an hour before the race. And of course, it was sitting like a 4x4. this wkd I tested how long it took to actually settle and I did it multiple times.

1st time I measured its settled height, then jacked it up and changed tires and put it back down. after 9 hrs overnight it had not even settled to half of the height it had gained. Took it out for a 5 mile run and measured again, still wasnt to my normal ride height, but close. took it on another 5 miles and tossed in some hard turns, measured and it was finally back to normal ride height.

2nd time I jacked it up at the track to see if one autox lap would be enough to settle it. nope. ran 4 runs and it still had not dropped to its normal ride height, although it was close.

all that being said...this must effect handling, somewhat. I know everyone does it because who the hell would drive to the track on their hoosiers...but still im curious how much difference in handling is there?

MisterMidlifeCrisis

Probably if the suspension isn't all the way settled, your alignment is probably going to be a bit off as well. You'll probably have a little less camber until it settles, so being a bit high and a bit less camber are both going to hurt, but probably only a very little bit. If the times are close, though, every little bit counts.

mountainbiker2

When I go to an autocross, I bet theirs 50% of us that drive to the track on Hoosiers.

When you measure it, the lot isn't exactly level, so it throws off your home measurements.

Steve A.

froggy47

One of the reasons I drive to/from on my a6's. About all you can do is find a bump/ditch near the event & drive over it as fast/as many times as you can. Usually the organizer will frown on this.

Bill Dearborn

If it takes that long to settle think about all of the alignments that are screwed up from the get go. I have seen many cars on an alignment rack raised so the mechanic can make an adjustment at the upper control arms and all they do when they lower the car is bounce it up and down a couple of times.

Bill

froggy47

travisnd

No need to bounce the car through a ditch or anything. Just rolling the car around will allow the tires to spread out and the car to go back to its set ride height.

The cars get stuck high when dropped back on the ground due to the nature of the SLA (short-long arm aka double wishbone) suspension. When the car is lifted and the suspension droops the wheel/tire moves inward and down on an arcing path. When you drop the car back down the tires hit the ground first and the wheels are stuck further in than then want to be due to the friction between the ground and the tires. As you roll the car around it allows the whee/tire to move outward and the car to settle down where it's supposed to be.

MisterMidlifeCrisis

I think the actual problem is that when the spring is unloaded, the height adjustment bolt material can move laterally along the spring as the contact point traces a shallow arc with the spring movement. When the spring is compressed again, the rubbery material is pressed firmly against the spring and it takes a long time for it to squirm back to a neutral position. It's kind of why when you turn the bolt, it can take a couple of weeks and a few hundred miles for the height to finally settle into its final position. Only here, when you jack up the car, you're not actually doing anything to deliberately break contact between the pad and the spring, so it may stay stuck together or at least not move as much.

travisnd

That's part of it. The spring adjuster bolt does move inward on the LCA as the suspension drops and it to must work its way back out, but it will do so in fairly short order. FWIW replacing the OEM adjusters with delrin ones eliminates this issue completely.



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froggy47

I agree this is the case IF you have CA bushings & spring adjusters that are all free to move easily (which they should be)

However, with stock rubber bushings and stock spring adjusters I have seen one corner (or more) "hang up" in the droop position (not all the way but some) and it's the devil to get the ride height back down. I found the speed bump/ditch process would accelerate it.

ritch ford

I have just installed Pfadt coilovers. Will this eliminate the problem?

Pfadt Racing

We definitely recommend driving the car around the block a couple times while making ride height adjustments, but just swapping tires over with a coilover car shouldn't make a huge ride height difference. Since the ride height is now contingent on the position of the spring captured in the spring perches and not on the position of the leaf spring pads which may travel on an arc you eliminate that possibility.

That being said, it's a good idea to drive around the lot just a bit before hitting the course anyway. You'll probably need to put a little heat in the brakes anyway, use it as an opportunity to focus and let the car settle into position before your first run.

Larkin251

When I go to an autocross, I bet theirs 50% of us that drive to the track on Hoosiers.

Alludc

as soon as I find that money tree im with ya!!!

froggy47

Street driving does not wear them that much (UNLESS YOU RUN A LOT OF TOE)

I run zero front toe & set rear toe at the track (takes 10 min if I am slow).

Pump the H's up to 40 psi for the commute, no heat cycle & minimal wear.

Well I'm not talking 500 miles each way, but I do 125 each way often.