I recently installed disk brakes on my 67SS and the passenger side tire rubs when crossing speed bumps or dips/bumps in the road. It seems the disk conversion set the wheels out somewhat from the drum brakes. I have 245/60's on Crager SS's with a 4.5 backset. I had no problem with the drum brakes. I have new stock ride height springs. Do I need stiffer springs?

I have the same problem with my 67 Camino. Put the disc brakes on and tire rub. I have Moroso front springs, 17.3 inch free height, and 90/10 shocks. I haven't cranked the shock setting up yet but that's the plan. Other wise I will change shocks and if that does not solve the problem, change springs.

Yep, I ordered new springs today, had to have them custom made to get the rate and length. I hope they're ok. I don't want to put different tires or wheels to get past this problem. Good luck with your problem, let me know if you get it corrected.

Troy

Troy;


What are the specs on the ones you ordered? And whom did you order from?


Tony

TonyS,

I ordered 17.5 free height, 11 loaded height, 360 rate. Based on my discussion with them, they said that is what they would recommend. I ordered them from Coil Spring Specialities. 128 bucks, compared to Year One at 230. I hope they work.

Troy

Troy;

Thanks for the information. Going to do the same.

After my disc brake conversion i have trouble with it rubbin on one of the places where the inner finder kicks down around with the bolts go in. I have's) aftermarket wheels (Torq Thrust 2's) i may have to look into some different springs as well.

I ordered Moog P/N 5244, 17.75 free height, 315lbs spring weight with tangential ends. Also order KYB shocks, KG4515. This combination should bring the front up 1 1/2 to 2 inches and still maintain a stif ride and eliminate the tire bottomining out insde the wheel well. The wheels are 8 inch ralleys with 4 1/2 inch set back, 245/60/15 tires.
I'll post the results when I get them installed.

Tony,

I'll be interested to hear your results. I haven't received my springs yet, but, I will also post the results when I get mine installed.

Troy

Same here on my '66 Elco. Disc conversion, 245/60s with 8" rims, pass tire rubs.

My report:

The 15X8s with 4" offset is not nearly enough. Stuck out way too far. Rubbed badly on the tread, not sidewall transition, hitting on the eyebrow of the fenderwell.

I put on a set of 15X7s, 4-3/8" offset (N-90 aluminum Z/28-Monte SS wheels) using the same 245/60s, still rubs, now on the transition from tread to sidewall, rubbing on the inner fenderwell as it attaches to the fender.

Tried 15X7 Rallys with 235/60s, still rubbed, same place.

This is on stock coils cut 1 coil.

I put in stock springs from a '67 Elco SB, and something must have gone wrong b/c the front was all the way up and would not come down. Veddy strange...... I'm a competent enough mechanic.

My plan: raise the car. That's ok with me since I am building a late-sixties style street/strip car. If I wanted a lower car, I would probably run a 225/70 on the front using a 15X7 wheel with 4.5" offset. That would fill the wheelwell nicely, and likely eliminate the rub.

If I may, I'd like to piggy back on this topic with an additional question: I just purchased a 66 Chevelle that had a disk brake conversion. I've been noticing what sounds like rubbing when I hit deep bumps. I thought it was a suspension issue until I read this posting. Now I'm wondering if I have a similar problem with tire rub stemming from teh disk brake conversion kit? Are there any tell tale signs I should look for to see what my actual rub source is?

Thanks for any light anyone can shed on this-

JT

I would just look at the inside of the inner fender well and see if you can tell where it's hitting. Mine was inside at the top.

Yep, mine too! It was very evident where the tire is making contact with the inner fender. I still haven't received my custom springs yet, bummer.

Troy

Yup, same here, still waiting for my springs. Hope to get them tomorrow.

Any recommendations on the type of springs I should go with...if I find I'm in fact bottoming out?

Theis is from my previous post, but I haven't received the order yet. I'll post the results when I install them.





I ordered Moog P/N 5244, 17.75 free height, 315lbs spring weight with tangential ends. Also order KYB shocks, KG4515. This combination should bring the front up 1 1/2 to 2 inches and still maintain a stif ride and eliminate the tire bottomining out insde the wheel well. The wheels are 8 inch ralleys with 4 1/2 inch set back, 245/60/15 tires.
I'll post the results when I get them installed.
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Tony S.

Got the springs today. Great service from Classic Car Sprins. Let you know the results.

Yep. On the passenger side. I put a little bit of chalk on the bottom of the fender opening. After hitting a couple bumps (and hearing what sounds like grating metal) I found chalk on the tire. It's rubbing on the lip of the fender on the lower front edge. I'm assuming I have the exact same problem you guys are experiencing. I will follow this thread closely to see what you determine. Hopefully your springs will do the job. That's my next inestment. And Shocks. Mine are shot. It'll be a while before I do any suspension mods though. In the mean time, anything you can pass will help me later on down the road. Thanks again- JT

JT;


Initially, with the stock 8 inch ralley wheel, the tire on mine was hitting the lower lip of the fender. I changed to 8 inch 4 1/2 inch set back and that solved that problem but did not solve the bottoming out problem on the inside top portion of the wheel well. If I get the time, I am going to try and change them out this weekend. Keep you posted.

Same here on my '66 Elco. Disc conversion, 245/60s with 8" rims, pass tire rubs.

My report:

Tried 15X7 Rallys with 235/60s, still rubbed, same place.

This is on stock coils cut 1 coil.



What disc conversion are you guys using?

On my 66, I swapped a set of 1972 Chevelle discs, AND lowered the car extremely (the front crossmember was about 2-3 inches off the ground, could NOT get the floor jack under the crossmember). I had a very slight rubbing on the passenger-side (outside of the tire would rub the inner fender attaching bolts), but only when jounced...

I forget the offset of my wheels (less than 4.5" BS though), but they are stock 15X7 Rallys (mid-70's Monte Carlo) with 265/50/15 tires... My tires are shorter, but wider...

Now that I re-raised the car up with Hotchkis 1" lowering springs (lower than stock but higher than previous), I have never heard any more rubbing... At full-lock, the tire did rub the 1-1/4 swaybar, but thats it...

If you don't see any rub marks on the tires and it sounds like metal-metal,
after I swapped in used parts in my disc conversion I had a metallic rub on hard turns, most noticable when slow. Turned out that the wrecking-yard splash shield had been bent slightly in removal or shipping, just took the pliers to it to solve the problem, after hours diagnosing it.

I ran 225/70/15 on a 7 inch GM ralley with 5244 spring in a small block 67 for years with no rubbing but a harsh ride. FYI

Doesn't lowering the car put the tire in closer contact with metal on top as well as the sides. I can see inner well marks from the tire with my stock suspension so I'm not sure I want to lower mine

I just found out my springs have been shipped, after waiting two weeks. maybe I can get them put on next week. I hope it solves my problem. I'll let you guys know the results.

Troy

Onabudget, the reason you were not having a problem is because you were running 7"" wheels. I'm running 8" Crager SS's with 245/60's.

Troy

By the way, my disk conversion kit is/was supposed to be all GM parts. I wasn't having any tire rubbing problems at all with my drum brakes. Only after I installed the disks did I have any tire contact with the inner fender.

Troy

Onabudget, the reason you were not having a problem is because you were running 7"" wheels. I'm running 8" Crager SS's with 245/60's.

Troy

I'm aware of that, I was just letting you know what range definately fits with those spring/disc combo.

The width of the wheel shouldn't have much if any effect... Its the width and height of the tires and backspacing... take the same tire mounted on a 7 inch rim and an 8 inch rim, and the area that is rubbing will be the same width... The sidewall may flex in slightly more and reduce the section width with the smaller rim, but the tread width (and thats the area that usually is rubbing, near the tread) will remain relatively unchanged...

I'm running 8 inch Eagle Alloys with 245/60's. I think that't the problem. I'm not sure about the back spacing. I need to pull one off and measure. I think it's 4. But it sounds like I'm having hte exact thing you guys are. I am going ot check the splash shield and other spots on the fender. This info you guys are passing is killer! It's helpingme diagnose/troubleshoot/resolve my issue. Thanks- JT

Rob,

I hope you didn't take any offense at my response regarding the 7" wheels. I should have been a little clearer after reading Tony's response about wheel width. If I were running a 7" wheel with the proper size tire, I wouldn't have any rub at all. I appreciate your information.

Thanks,

Troy

No offense at all. Just to let you know many people have problems w/ 8" wheels on 66/7 fronts. 4.5 b/s on a tire size that works is still usually very close. Did you check the database?

Got my springs in today, I'll let you all know the results as soon as I get them installed.

Troy

I got my springs installed and also new shocks. Unfortunately I still have a little tire rub in hard dips. The springs definitely helped, but, I guess I need a little more rate. The rate I have is around 384, compared to stock 320. I'm guessing that a rate of around 400-410 would do it. The ride with the new springs is very nice, just a little firmer, which I like better than the stock "float" feeling. I don't plan on changing them again anytime soon, maybe some day. I hope this helps some of you guys that are/were having the same problem as I was.

Troy

Does a higher rate number mean the car settles faster? Or does it not bounce as much, meaning less travel? ThanX

Jubee,

A higher rate means the spring will have less movement, thus, making the ride a little harsher and limiting the movement of the body.

Troy

ThanX. Sounds like that's in order for me.

Another question though: If I want to raise the rearend a little bit off of level, say about 2 inches, what's the best course of action if I run standard springs all the way around? Air shocks? Or should I simply go with larger springs?

Jubee,

I, personally, would do air shocks :)

Troy

The factory disc setup has a slightly wider track width than the drum setup. That puts the tire closer to the outter wheelwell and can cause it to rub. If you lower the car it not only gets closer vertically but because the A body stock suspension has + camber gain in jounce (backward from what you really want) it makes the tires lean outward at the top making them closer still (unless you reset the camber after lowering it). Stock settings call for something like +.25*-0* of camber. Silly when you consider that they have a + curve too! You can easily run -.5* on the street with excellent tire wear and better handling. It`ll also move the top of the front tires inward and away from the fenders giving you some more clearance. You can also gain a lot of room by revising the geometry so that the tires don`t move out to meet the fenders when you hit a bump. Just for example our Stage 1 packages make the camber curves basically neutral and the Stage 2 reverses the curves to get proper - camber gain in jounce (compression) so that the car not only handles much better and leans less but the tires actually move in and away from the fenders. Other options include getting wheels with more backspacing,although you`ll start getting close to the LCAs and frame rails.
Last are factory ZQ8 S-10 pickup lower suspension arm bumpstops. These things are really neat. They bolt right onto a Chevelle. They`re made from an orange high tech cellulose elastomer instead of rubber. They`re much taller than the A body stops and have a very gradual progressive rate. You don`t even feel them touch and they`re actually intended to be partially compressed much of the time. Because of the material they`re made of they decompress slower than the car`s suspension does so they don`t add any bounce on the rebound. We`ve used them on a number of cars to slightly improve the handling and mostly to eliminate tire rub or header scraping. They`re always a big help and they only cost about $35pr. from any Chevy dealer. Marcus SC&C

Marcus,

Great information! I appreciate it! Do you think it would be ok for me to tell the guys at the alignment shop to reset the camber to -.5*? Would that be ok to run on my 67SS? Thanks for your help.

Troy

I ordered Moog P/N 5244, 17.75 free height, 315lbs spring weight with tangential ends. Also order KYB shocks, KG4515. This combination should bring the front up 1 1/2 to 2 inches and still maintain a stif ride and eliminate the tire bottomining out insde the wheel well. The wheels are 8 inch ralleys with 4 1/2 inch set back, 245/60/15 tires.
I'll post the results when I get them installed.
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With the above installed, has raised the front 2 1/2 inches. Just what I was trying to achieve. Plenty of room and plenty of tire clearance from the front fender lip and the top of the outer fneder lip.