Front tire rub is getting serious

[Mystic_Cobra]

My front tires have rubbed holes in my front inner fender liners. Not a big deal except that I'm rubbing through the wiring harness on the left front.
Between my 2nd and 3rd track day at Summit Point this weekend, I pulled the plastic liner and tie wrapped the wiring harness up out of the way as best I could. There's not much room up there. I rewrapped the harness with many layers of extra electric tape. By the end of the day today, I'd rubbed through again and I can see bare wires. I'm assuming this is bad!
I recently removed my front strut brace to clear my AFM powerpipe. The problem seems worse now, but I can't be sure it contributed.
My front end bushings are all stock.
It has 107,000 miles on it. I drive it every day and to weekend track events.
I have H&R Sport springs (unknown mileage) - the PN is for a pre-93 Mustang, not sure if that matters, I didn't buy them.
Shocks are tokico blues (unknown mileage).
I have 275/40-17 RE730s on Cobra Rs.
The ride height looks good at all four corners.
I'm also wondering why every track I've been on recently has a dip right in the hardest corner of the track that bounces my front end up and down. It happened at Gingerman, Summit Point, AND Jefferson Circuit at SP.

Please help!!!


:(

[1-QIK-SNK]

Would the front of the car be to low? What is the hight from the top of the fenderwell and the ground? I know that Kenny Brown sells a rubber spacer for the front springs to raise it up about 1/4 to 1/2 inch. That might be some thing you might want to try.

One other thing you might want to try is get a stiffer(stronger) springs up front. Sounds like the springs might be compressing to much . Good luck

[wildhorsesracin]

That's proof that your driving the car harder!!! Time to move up to stiffer springs...

[svt_coupe]

I had the same problem. It started to rub at VIR on the full course after hard braking at the end of the back stretch (uphill, lots of compression). This is a relatively common problem, so don't fret. You can get the harness out of the way. But, you really need to pull the fender liner out of the way and remove a bunch of the clips that hold the wiring in place. This will give you the slack required to relocate the harness to a safe place. You want to make sure you move that harness - I have heard (second hand) of cars catching fire because of it. And obviously re-tape the exposed wire.

Stiffer springs will help, but I'm running the 750-800 springs and still get some rub (only under what I think is extreme braking). I could probably go stiffer, but yours is a daily driver so that's about as stiff as I'd go for a street car.

[Mystic_Cobra]

I have decided to replace the bushings in the front end first, expecially since I have over 100,000 miles. I might try to move the wire harness again, but I couldn't find a really good place for it. I got back up inside the fender after my second day on track and unwrapped and rewrapped that section of wiring. Luckily no cut wires, but three were showing shiny copper wire. The harness is a little smaller now without the plastic wire holder and some new tape, so it is further away from the tire.
I think the only bushings that are a pain are the lower A-arms. I'm not going to fight with them and don't have a press. Maybe I'll save them for another project or get replacement arms.
I think using narrower track tires will help a bit, too. We'll see how it goes at the next event. I'm considering going from the H&R Sport to Super Sport as my next step.

Jimmy Bost

[wildhorsesracin]

If you swap out the LCA bushings with the delrin ones from Max Motorsports you won't be disappointed, they make a huge difference in how the front end handles, takes out lots of the 'sloppy' feeling...

Just my .02

[Mystic_Cobra]

Another thought on this issue that I was hoping to get some feedback on. I got my new urethane bushings for the front end in. - The day I left for Lowes :(
I'll be putting those in soon. I DID continue to have some rubbing in the left front in the two infield right handers that preceed and follow the straight. I was able to move the harness again to a safer place which I think has maybe cured that problem. I was still taking it easy in those turns once I isolated the rubbing to those turns. I had my first electrical problem associated with this rubbing and I'm glad it was a minor one. When I rubbed through the wiring harness, two wires were exposed and touched one another. I retaped the wires at the track and everthing seemed fine. Nothing serious (luckily) but the cell phone chargers (cigarette lighter) were not working on the way home. Turned out to be a burnt fuse and seems to be okay now.
Now the "other thought", a local Mustanger, whose also a suspension guy, suggested that my Caster may be too much!
It seems like a logical thought especially since my rubbing is happening just above and behind the top of the tire, where no one else is having the problem.
My plan is to install my new front end bushings and then get the alignment done. My steering wheel is crooked again, anyway.
My MM catalog says that about 4 degrees of positive caster is okay. Anyone else have any suggestions for my specs. I didn't get the specs from the guy that did my alignment after I installed the MM CC plates.
What specs should I use for aggressive street? and for track?
How do I mark the plates so I can change them at the track?
Can I switch to track mode with the tires on the ground?
thanks

[tgentry]

Jimmy, I'm happy with my Steeda offset urethane bushings. If you think you have too much caster that may not be the way you want to go though.

I change from street to track alignment regularly. I have the Steeda C/C plates so I just scribed lines right on my shock towers. I have moved them with wheels on the ground, but I don't recomend it. I had to use a large screw driver to move them, then strain to hold it in position while I tightened a couple nuts. Life is much easier if you lift the wheel off the ground.

[STU]

Those Tokico blues are a great shock for street use (I have them on my car) but they are not firm enough for track use. IMO
Sounds like you are doing a lot of events. Time to up grade the struts. Koni single adjustable would be a very good choice. Also the installation of a torque arm will help a lot to reduce the nose dive on hard braking.

[Mystic_Cobra]

Thanks for the feedback, guys.

Tom, you mentioned offset bushings. I purchased LCA bushings, sway bar bushings and end links, and tie rod dust caps. I think you're talking about the steering bushings, which I DID NOT get.
As for the CC plates, I will keep that in mind and plan to get two alignments done (with marks), one for track and one for street.

Dave, thanks for the advice on the struts, I'm looking for advice after MM suggested the new Bilstein units that cost $800 on top of the $250 for the H&R race springs! If this was going to be my track car, I'd be more willing to spend a grand here. I am planning to learn to drive with this car and then start building a dedicated track car in a year or two. This is also why I'm hesitant to do the torque arm setup. I am planning to get the full length MM SFCs, but I haven't been convinced on the torque arm-yet. Also, several guys have said that my nose dive isn't that bad at the track.
I want this car to handle well, I will continue to use it on track occasionally, and I *will* keep this one in my permanent collection.
Jimmy

[tgentry]

Jimmy the I have offset control arm bushings. They are designed to move the control arms as far forward as possible within the stock K-member. GW and Steeda both sell bushings like this, the GW's are Del-alum the Steeda's are urethane.

I also put in offset urethane rack bushings. I'm told they aren't really necessary on '96+ cars but I was having trouble finding non-offset rack bushings.

If you'd like to go with Bilstein's I can give a place with a killer price on the '00 R struts. Let me know, I'll have to look it up. The only bad thing is most coil-over kits won't work with them (MM is the only one I know that works).

[Mystic_Cobra]

What is the advantage of moving the control arm forward? I know wider is better, but is longer better, too? ;)

[tgentry]

Moving the control arm forward:

Better weight distribution. Think of it as moving everything except the front wheels back.

Longer wheelbase. Just as in wider is better for cornering, when you're braking or accelerating longer is better.

More caster. Caster helps both in centering the wheels for directional stability, plus it adds some negative camber to the outside wheel as you turn.

Obviously moving the arms forward 3/8" or so isn't going to make huge leaps in any of these areas, but it has to help some. That's why Griggs and MM move the wheels forward with the K-member.