jd13

iTrader: (3)

First off, I want to say thanks to those that have helped me with my suspension setup questions. I'm nearly done with it all. :p I must say I love the way my car handles now, and the tires grip the road so much better in all situations. Not to mention I've learned a lot from you guys.

Car is a 99 Z28. Stock tire size, 245/50/16. Eibach pro-kit, BMR sfcs, BMR LCAs, BMR relocation brackets, BMR adj phr.

The problem: When going around a turn and giving the car some gas, the appropriate rear tire will rub the inner wheel well. This is only a semi-hard turn when accelerating.

The question: Will a sway bar take care of the body roll causing the rubbing? If so, what size etc would work, I'm not very knowledgeable on sway bars etc. If not, what would fix it?

Viper

iTrader: (6)

Wow, that's interesting. Are you sure the rear end is centered? I do not believe sway bars will fix what you are describing. People have 'beat' in the inner fender with a hammer, but usually guys running 315's.

Cal

iTrader: (1)

When you lowered it, it probably caused the rear axle to shift to one side. You will need an adjustable panhard rod to fix it.

Viper

iTrader: (6)

He's got one:

Car is a 99 Z28. Stock tire size, 245/50/16. Eibach pro-kit, BMR sfcs, BMR LCAs, BMR relocation brackets, BMR adj phr.

trackbird

iTrader: (4)

I'm running the same size tires as you and having no problems (lowered 1.3 inches or so...see sig). The only time I have problems is on my 255/50-16 Eagle GS-CS race rubber (when running autocrosses). They have rubbed shiny spots in my inner fenders (there is a pic on the front of my website taken at an autocross that shows about the max body roll I am getting). I'm not saying that you can't have a problem....but that seems odd (that it's rubbing). What suspension parts are on there so far?

jd13

iTrader: (3)

Car is a 99 Z28. Stock tire size, 245/50/16. Eibach pro-kit, BMR sfcs, BMR LCAs, BMR relocation brackets, BMR adj phr.

PHR is adjusted perfectly according to BMR's directions. The wheels also appear centered to the eye. Yes, it is quite weird. The shiny spots look cool, but eh...

Shocks maybe?

trackbird

iTrader: (4)

Did your relocation brackets "pull" your axle forward at all? I'm thinking that could be the problem (or part of it). I doubt that shocks will help the rubbing (but they will help the handling). Something has either moved or is flexing....we just have to figure out what it is....

Viper

iTrader: (6)

Good point; did you make the LCA's parallel in the LCA relocation bracket ( parallel to the ground, no angle to it ).

Also : "The wheels also appear centered to the eye"

Don't trust your eye. Use the plumb method of hanging a plumb on a string outside your rear fender well and measuring side to side.

jd13

iTrader: (3)

Yes, initially the brackets did "pull" the axle forward. That was corrected the LCAs were pried in, and are now at a straight angle.

I will use the plumb method again. When I did it before the LCA/bracket install, it was perfect. I know I haven't changed the phr. I will check again.


edit: Update: Ok, after a night of some driving and experimenting...Only the rear drivers side tire rubs while making hard right turns. Making left turns creates no rubbing.

Viper

iTrader: (6)

Think about it; if you adjusted it before the LCA's and relocation brackets, you will more than likely have to remeasure and adjust the PHR because the geometry DID change.

trackbird

iTrader: (4)

When making a right turn, the panhard rod is loaded in "compression". Under "compression" the PHB may exhibit some flex (depending on the material that it is made of and the stiffness of that material). During left hand turns, the PHB is stressed in "tension" and unless it will stretch, it will not allow any movement.

My rubbing is most pronounced on the drivers side as well. I am starting to suspect that the BMR PHB is not rigid enough to handle the load that it is being asked to handle. Part of me says that 1/25 inch chromoly (I bought the chromoly PHB with "race" ends) should be more than plenty strong. But, application is starting to make me reconsider that thought. I'm going to have to do some more "research" and see if I can gather any more info. I am starting to think a call to BMR is in my future as well.....

Viper

iTrader: (6)

Good point. I use the GW bar, and see no flexing.

From TR's site:

"BMR's Tubular Panhard Rods are available in either non-adjustable or adjustable versions and are constructed of strong 1.25" x .095" steel tubing for a lighter yet stronger component."

"Global West ( GW ) Large 1-1/4" outside diameter, .125 wall roll cage tubing stops deflection."

Sounds like the GW piece is stronger.

Also, here is LG's piece:

"All units constructed of 1.25 DOM heat treated steel tubing"

Perhaps the .095 of BMR is not strong enough?

jd13

iTrader: (3)

It's starting to make sense. I have the BMR tubular with poly/poly combo. I figured for mostly street driving that would be enough.

I did remeasure the wheels etc, and they are off by .25" now. I'll post back later when I can test it out.

Viper

iTrader: (6)

That 1/4" was lost when you used relocation brackets; you relocated the rear end!!

Good luck, glad you're doing this stuff yourself so you learn! It's addicting....

jd13

iTrader: (3)

Ok, so I adjusted the phr. The wheels are now off by less than .1 of a centimeter. I can't do much better. :/

The rubbing from the rear drivers side tire is still there. Ugh....


edit: sorry, typos

98_1LE

iTrader: (17)

Another option is to remove the wheel, make sure the back seat is up, place a short 2/4 over the shiny spot and smack it with a 4 pound hammer 5=8 times as needed. Spray with undercoating, enjoy. Works with 315's, so I would think that 245's would be easy!

trackbird

iTrader: (4)

98_1le has a good point and it will likely fix your problem.

It still bothers me that there is enough flex that the 245's are rubbing. Making a little clearance with a hammer will cure the symptoms....I'd still like to cure the problem....But, a little clearance will do in a pinch....

Kevin

jd13

iTrader: (3)

Yes, I agree trackbird, it really bothers me too. 315s I'd understand, but 245s.... It's not a huge necessity that I fix it right away. I would also like to cure the problem, or at the least, figure out why.

98_1le, thanks for that tip. I wasn't sure exactly how to pound away if it comes to it.

Viper, I'm really thinking that you are right. The BMR phr isn't strong enough. But why isn't it strong enough for a nearly stock car?

1. Perhaps if I backed off the Eibach springs to BMR's? That would net me back around .5" of drop. I still have my stock springs that I am willing to put back in for a day just to see if that would fix it.

2. BMR is 40 minutes away from me. I was planning on making a trip over there in a couple days to possibly pick up a torque arm, or my buddy was just going to buy some things. I will talk with them and hopefully something will come of it.


I'll keep updating when something happens. Thank you for all the help so far. I'm not giving up on this problem.

trackbird

iTrader: (4)

I'd not change springs....there is another cure...I"m sure...