Clearence issues with HR springs?

[jhandy]

I have aftermarket wheels that required me to put 7mm HR spacers on all four corners. The (rear) wheel's rim only clears the strut shaft by 2mm. I plan on instaling the HR sport springs with a 1-1.5 inch drop.
What do you think will happen with my clearence issue? Will it be closer to the tower? Will I have to get larger spacers?

Thanks for the help,
James

[Sboxin]

James,

We have an '02S w/H&R lowering springs.
The spring tower is above the tire = so no difference in clearance with same wheels and tires.

When you change the wheel/tire size and offset then you will be looking at more spacer.

It sounds like you may already have larger tires/wheels if your clearance is 2MM.

We have used16.5/18MM on the rear and 15MM on the front with 8x18 and 10x18 BBS 911 Turbo wheels and KUMHO V710 245/285 tires.

When you get the springs on and are setting the alignment you may wish to consider various size spacers for inside/outside clearance and appearance.

A photo of our setup is attached.

Take care,
Ed

[Quickurt]

Originally Posted by jhandy

I have aftermarket wheels that required me to put 7mm HR spacers on all four corners. The (rear) wheel's rim only clears the strut shaft by 2mm. I plan on instaling the HR sport springs with a 1-1.5 inch drop.
What do you think will happen with my clearence issue? Will it be closer to the tower? Will I have to get larger spacers?

Thanks for the help,
James

With only 2mm clearance between rim/strut, you may get more tire flex that that on hard cornering. It may or may not be enough rub to damage the tire, but it will put sufficient heat into the shock to effect it's performance.
I mention this for your safety and the possibility of handling "coming and going."

[jhandy]

Quickurt, I never thought of that.
When parked, there is 2mm of clearance, I looked at the strut tower and there is rubbing of what I assume is the tire/rim.

Looks like I should get larger spacers.

But here is another question........I was told that the larger the spacer, the larger the lever arm of the set up will become and that puts pressures not engineered into the design of the bearings and axile/cv joints/struts.

I went with 7mm because it was the least I could get and still clear the strut tower, and 5mm is offered by porsche factory as an option, so I assume that it is within tolerances.

Any thoughts?
James

[Sboxin]

Originally Posted by Quickurt

With only 2mm clearance between rim/strut, you may get more tire flex that that on hard cornering. It may or may not be enough rub to damage the tire, but it will put sufficient heat into the shock to effect it's performance.
I mention this for your safety and the possibility of handling "coming and going."

WHAT??

I'm sorry, but Quickurt, you will need to post some references to support your conclusion about tires too close to the damper causing overheating and performance changes.

I say this in a nice way

The whole hub assembly heats up from the brake rotor heat. I don't follow the reasoning about tires heating the damper? Brakes get 300 to 800 degrees, tires on a track may get to 200. There is something I am missing here.

And, to be fair to James, I don't intend this question to displace his question about spring clearance. Hopefully some others have some experience in the H&R Sport springs clearance.

...looking forward to your response,

Take care,
Ed

(also older than dirt )

[Quickurt]

My reference is experience. The additional heat I am referring to, is not normal heat coming from brakes, hubs, etc. but heat from the tire rubbing on the side of the shock, if they do flex enough to actually rub.
McPherson strut cars already have more heat into the shocks than conventional suspension cars, as the shock bodies are actually a part of the hub/mounting assembly. Coventional shocks get heat only through a very small connection point and through the surrounding hot air in an enclosed wheel well.
Adding the friction of a tire rubbing against the shock on a regular basis (laps) is additional heat they do not need.
That was my concern and just something for the original postor to consider with his 2mm clearance.
I understood your question in a nice way and respond accordingly

[Sboxin]

James,

There are many Boxster forum posts describing spacer use from 5-18MM. There may be one who said he had a problem with a wheel bearing. But, the bearings will fail anyway with mileage and there are several postings of this normal failure.

2MM clearance: I remember a description of a "credit card" thickness clearance by an established Boxster forum poster (on a different board).
We had a wheel rubbing on the damper; turned out to be a bent wheel and we ground it smooth to solve the rubbing. The wheel would only rub and very hard right hand turns on the track.
If you have a tire rubbing yhe tire would fail before the damper would have any problem with heat, IMHO of course.

James, when you get your project done put up a photo on the forum

Take care,
Ed

Quickurt,

Thank you for your explanation.
I respectfully agree, to disagree.
Ed

[Quickurt]

Originally Posted by Sboxin

Quickurt,

Thank you for your explanation.
I respectfully agree, to disagree.
Ed

Ed,
I raced a VW GTI, Improved Touring A, SCCA car quite a few years ago, now. Goes with the older than dirt.....
Anyway we did a then legal coil-over update by modifying the struts by removing the spring land but leaving the boss of the land as a sleeve around the strut. We then used that for the mounting base of the threaded coil-over sleeve. A way around the no coil-over rules saying you could not cut the welds off from the original spring land...
We also had strut hub failure problems with those cars and one solution was to use earlier wheels that had less offset that would reduce the lever arm action on the hub. (very same thing as warnings now on using spacers on Boxsters)
We got a set of aftermarket wheels (bargain, I thought) that had to have spacers to clear the strut. We then started having handling problems that progressed through the race, as if the tires were heating up and going away.
It turned out that the tires were rubbing the front shocks during cornering and Dick at Carrera Shocks said the McPherson heat was already about all the shocks could handle. Admittedly, this was quite a few years ago and all technology has improved.
We went back to the original wheels and it stopped (but the strut failures returned).
We finally made several sets of 1/8" spacers to figure out the clearance we had to have and cured both problems.

By the way, that's one bad-ass looking 986!!

Kurt