Rear tire rubs on bumps - Page 2

Blas · #21 (**permalink**) 04-13-2009, 05:35 PM

Sounds like that's your problem. The proper wrenches are available from Bilstein, and you must have 2. They are about $8 each plus shipping.
You'll need to adjust each wheel one at a time, then roll the car back & forth a little to get it to set up right, then do the next wheel. You usually start with a rear and go all around and then back to the first one you did and start again. Don't forget to use a jack stand every time you go under a fender, I know it's only for a moment to make a quick adjust, but it only take a fraction of a second to experience the effects of gravity first hand and to personally confirm that Isaac Newton and Albert Einstein were correct.

JCoop · #22 (**permalink**) 04-15-2009, 04:29 AM

Quote:

Originally Posted by Naboo

I measured the ride height. I'm at 25". Sounds like I need to start there. I'll go to 26" and see if it goes away (since Blas is 'a bit lower'). I'll let you know if it work (if it ever warms up here).

Thanks for all your input!!

Recommended ride height is 27" all around from the pavement to the fender lip going through the wheel center. I have mine at 26.5" with 17" wheels. It looks very low as it is. 25" is way low, and you could have too much neg. camber all around.

Silverback51 · #23 (**permalink**) 04-15-2009, 07:30 AM

Please remember that tire size will affect the measurement from the floor to any body feature.

trularin · #24 (**permalink**) 04-15-2009, 08:37 AM

After you roll it back and forth as stated by Blas, you might want to carefully push her down and let her spring back up.

Blas · #25 (**permalink**) 04-22-2009, 06:53 PM

So, did the ride height adjustment fix the problem?

madmaxx · #26 (**permalink**) 04-22-2009, 07:08 PM

I have the 275 15 with a ride height of 26" and zero nada rubs, i thought i had one but it was the sway bar bushing needing lubricant. I love the look when the tires are tucked up under the fender the way they are supposed too. get rid of the 315's and if switch to the 295.

maxum_101 · #27 (**permalink**) 05-14-2009, 12:04 PM

when adjusting the front height, should an alignment be done? if so what are the specs?

Blas · #28 (**permalink**) 05-14-2009, 12:38 PM

Not necessary.
What height was it at, and what did you adjust it too?

maxum_101 · #29 (**permalink**) 05-14-2009, 06:46 PM

my front is set at 27 inches and my rear is at 25.5 inches. im looking at getting a set of 17" rims and tires and will prolly have to raise the back end a bit to compensate i would like to lower the front end down a bit, a bit to much space from the top of the tire to the fender lip, and my steering wheel is not center, ive tried moving it over 1 spline and no luck it still looks off, but now towards the other side,so im guessing to fix it an alignment will have to be done .
also... to lower the car down i will have to compress the spring.... is that right?

maxum_101 · #30 (**permalink**) 05-14-2009, 06:52 PM

Quote:

Originally Posted by FUNFER2

When I was setting up my suspension, I made two 8" length of round aluminum that was threaded inside, and bought four heim joints to make shock replacement. I removed the coil overs and mounted these in place. I was able to adjust the ride height where I wanted and since we race sprint cars, we know a lot of modified racers so, I borrowed a set of four weight scales.

Before I started, each corner was so different in weight, I could not believe it. After adjusting, the weight is almost the same on each corner and the percentage front to back now is 51% in back and 49% in front.

Here's a photo of the tool I made. If your interested in making a couple (it's cheap) let me know or I could mail them to you, just for postage costs.

It's the best tool I've ever had to adjust weight, measuring for wheel & tire size and setting ride height.

how do you adjust the weight at each tire? is it done by the ride height?

JCoop · #31 (**permalink**) 05-16-2009, 03:04 PM

Yes. Usually best done after a proper wheel alignment.

Adjustments should be made with the sway bars disconnected, and with driver weight and half tank of gas. After adjustments, reconnect swaybars so there is no pre load on them. Not easy. took me 4 hours and 2 cases of beer and 2 friends.

Tonkin NZ · #32 (**permalink**) 05-28-2009, 01:59 AM

Hi. I have 2828 (w. 315/35/17s) and compared to an earlier SPF there is a bracket on the inside of the tire well and it is the bolt on this that rub (mine just the left side).

Replace the bolts with lower profiles and that helps but still looking for solution myself.

cobras · #33 (**permalink**) 07-16-2009, 09:44 PM

i set the front at 26 inches, and the rears at 25.75. this is with 17" wheels. no test drive yet, will report back soon with any rubbing or problems.

Quote:

Originally Posted by Blas

Not necessary.
What height was it at, and what did you adjust it too?

madmaxx · #34 (**permalink**) 07-19-2009, 11:36 AM

I have my rear ride height set at 25.75 with p275 r 15's with full tank of gas and never came close to rubbingg

cobras · #35 (**permalink**) 07-19-2009, 05:03 PM

took the car out for test run, ride height is good, but when i go over 60 mph i get a vibration, i just got the wheels (used) the wheels were all balanced before they were sent to me, but i still have that vibration/shake over 60 mph. what is this road force balance i keep reading about, what is it and how is it done? i cant be driving like this and would like to get it fixed asap.

madmaxx · #36 (**permalink**) 07-19-2009, 05:11 PM

Road force balance. It is the matching of the tire to rim. Your rim is not perfectly round and the sidewall stiffness is not uniform around the diameter of your tire. The road force balance matches the high spots on the rim to the soft spots on your sidewall. It is in my opinion the best thing since sliced bread. Needless to say it is only as good as the operator, usually a teenager.

Once the wheel and tire are matched than a traditional style balance is done on the assembly.

Also inflate your tires to 18-22 psi, these cars only weigh 2500 lbs, if you inflate to 32 psi you will wear the center of your tire out.

cobras · #37 (**permalink**) 07-19-2009, 05:29 PM

thanks for the reply

i have my psi at 25 psi 17" PSE wheels michelin pilot sport tires.

i will have to call around to the local tire shops to see who does this road force balance. i hope it does get rid of the vibration.

Xavier · #38 (**permalink**) 07-19-2009, 11:06 PM

Road Force balanced can be done at generally well equipped car repair centers, mainly dealerships or professionals who mount racing tires. Basically, although someone technically sound has to be running the device, the machine does the science behind it. I learned about it after having similar vibration issues. Its amazing how many people you call who specialize in tires have never heard of it.

http://www.hunter.com/pub/product/balancer/index.htm