Got a Body Rub over the Weekend.......

[Kneedrager]

I wish it was as exciting as the title, but it had to do fender clearance not a message. I was just up in Pocono (Pennsylvania USA)for three days with NASA and had tire clearance issues on the SR3. The first two days we ran a combination of one or another of the Nascar turns along with assorted infield configurations and I noticed no issues. On the third day we ran Nascar turns one and two along with the north course infield which is a very high speed, banked configuration. For three quarters of the track you put it to the floor and held on...!

I noticed that my drivers rear tire was getting pretty severe rubbing on the outer edge from the upper front portion of the wheel arch. I tried adding a considerable amount of preload to the spring on that corner of the car along with stiffening the rear bar and was able to minimize the rubbing but not eliminate it. I am running the 10" rear wheels with 260/605R tires which I'm sure doesn't help. I probably should have adjusted out a little of the wing angle to minimize the downforce but going around that bowl flat out makes you want all the downforce you can get.

Does anyone trim the wheel arches for more clearance or are there any other tricks to avoid this issue? On a separate issue, this was the first weekend I ran with my dive planes. While I think the ultimate top speed may have suffered a couple of MPH, I definitely think the car felt more stable.

As always any help will be greatly appreciated.

Scott

[fergus]

Kneedrager said:

I wish it was as exciting as the title, but it had to do fender clearance not a message. I was just up in Pocono (Pennsylvania USA)for three days with NASA and had tire clearance issues on the SR3. The first two days we ran a combination of one or another of the Nascar turns along with assorted infield configurations and I noticed no issues. On the third day we ran Nascar turns one and two along with the north course infield which is a very high speed, banked configuration. For three quarters of the track you put it to the floor and held on...!

I noticed that my drivers rear tire was getting pretty severe rubbing on the outer edge from the upper front portion of the wheel arch. I tried adding a considerable amount of preload to the spring on that corner of the car along with stiffening the rear bar and was able to minimize the rubbing but not eliminate it. I am running the 10" rear wheels with 260/605R tires which I'm sure doesn't help. I probably should have adjusted out a little of the wing angle to minimize the downforce but going around that bowl flat out makes you want all the downforce you can get.

Does anyone trim the wheel arches for more clearance or are there any other tricks to avoid this issue? On a separate issue, this was the first weekend I ran with my dive planes. While I think the ultimate top speed may have suffered a couple of MPH, I definitely think the car felt more stable.

As always any help will be greatly appreciated.

Scott

I'm guessing that with a high speed banked turn, plus the aero downforce compressing the car towards its bumpstops, you should seriously consider higher poundage springs (and adjust the damping to suit). Running a car at high speed where the tyre is rubbing, is waiting for an accident to happen. I'd contact radical and see if they can suggest a suitable spring rate to swap out the current items for.

Compressing the current spring to try and compensate is not the answer, as you risk the spring becoming coil bound and running out of travel, leaving you with the side wall of the tyres as the only suspension.

Your corner weights would be all over the shop, esp. for an oval.

Remember, safety first, fun last!!!

[Kneedrager]

Thanks for the reply. I agee the springs could probably be stiffer. I did not get a whole lot of information with the car when I bought it, so I'm going to have to disassemble the shcoks and springs to find what is on the car currently. Where (if they are) would the lableing on the springs be? Interior of the coils? The car is an '02 with what I believe to be the stock set-up. What pound springs came as stock?

Thanks for any insight.

[bazzerv8]

Hi there the stock springs are 300lbs at the front and 350lb at the back if you are running high down force spec you need to up the poundage

if you want to stop the tyres mashing into the body pre load is not the answer. Best thing is to get some "c washers" these fit on the shaft of the shocker and restrict how low the body can go and thus avoid the tyre body contact thing.

hope this helps