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Discussion Starter · #1 ·
I have been battling slight rear tire rub for a while now and have decided it’s time to add something that will limit the axle travel (i.e. – stiffer rear suspension). My setup is the following: 2003 Mustang GT solid rear axle and stock 4-link suspension w/ 210 lb/in coil springs and stock shocks, 8” wide rims w/ 30mm (1 1/8”) offset, 245/45 R17 tires. The axle is offset to the body fenders by approx 1/4” (9/16” closer on drivers side than pass side). The axle is offset to the frame by ~3/16” (measured brake rotors to frame). I have attempted to shift the axle to the frame with no luck. The 4-link suspension has no side to side play even with all the bolts loose.

I have the ride height set at about 5.5” with no driver or passenger. When my son and I get into the car the ride height goes to about 4.5”. The drivers side tire rubs only when cornering hard and hit bump at same time. The rub is up inside the fender (not on the lip). Measuring from the tire to the rub spot is about 3” with no warm bodys in the car. I have the drivers side coil spring adjust as high as it will go on the FFR spring perches. Also added the stock sway bar, which did help, but did not eliminate the problem.

Options that I am considering to fix the problem:
1) Find 300 lb/in coil springs. Have not found any yet. Unknown cost
2) Purchase rear coil over shocks w/ 250 lb springs - $350
3) Purchase air adjustable shocks, Gabriel # 49234, will give 0-550 lb add’l capacity per shock - $62/pair.

If you were me, trying to do a budget build, which way would you go? Are there other options that are available? I am leaning toward the air shocks at the moment as this is cheaper
and with still give me adjustability down the road.

Thanks, Randal
vroom vrooooom!
 

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increasing your shock and/or spring rate can eliminate the problem. my car had a stock 4 link rear and also a stock sprung IRS rear, both of which had a huge amount of travel.

however, there should be room for the tire to fit up inside the fender and the limit of travel should be taken with a rubber bump stop on the suspension. this is important because it softens the limit of travel- if it is too abrupt the wheel will act as it is has no suspension and may instantly lose traction.

if the tire is hitting, you may need to change the backspace of your wheels to move them where there is more room, or use a narrower tire if there isnt more room on one side. i would not try to shift the 4 link suspension, it needs compliance in the bushings to work properly.

james
 

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On the little more money side VPM rear coilovers will be the best long term investment you can make.On the cheaper side.1-Did you cut the stock springs per FFR? If so they are too short to get enough adjustment upwards.I have a set that i just heated and opened up the top winding so there is a lot more adjustment available.Email me and they are yours for shipping.2-you can shift the axle sideways by modding the upper control arms.If you have welding available you just weld a washer on the outside of each axle end bolt hole offsetting the hole a little-say 1/16 inch.then grind the original hole to match.Make one arm longer and one shorter.Problem is how much to change arm length to get the lateral axle movement you need.3-I remember checking specs from Monroe ( I think) that indicated that later model (say 95+) rear shocks had bump rubbers built-in.maybe there would be some help there.4-Live w/ it. my MkI and my MkII both do exactly as you describe always the driver side. I swear that fender is lower than the other side when the frame is equal on both sides.
 

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Craig,
The same can be done by using adjustable uppers. However, are you not just changing the square of the axle? Unlike a 3 link that has sid to side adjustment, driving one side further aft than the otehr puts the rear out of square.

BTW, I have been wrestling this since I got the car on the road. VPM coilovers are my next stop.
 

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Put in a spring rubber and a round of wedge.?? uhh Sorry race flashback from yestreday. The axle assy you have is too wide . Rich Oben North racecars has brackets to move the brakes inboard to Fox Mustang width and also shorter axles. Work perfect on My mk III . I have 315 tires way in the fenderwell. I guess itdepends on the whell tire combo . Richard is the whel man speak to him he set me strait. Bob
 

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Discussion Starter · #7 ·
Man you guys know how to spend my
. I am already over budget. lol! Will have to save those expensive ideas for a later upgrade.

My coil springs have NOT been cut per FFR instructions. Adjustable upper control arms and spring rubbers sound doable.

Any ideas on how to install bump stops? The stock mustang had one bump stop over the diff.

Noticed today while measuring that the hood opening is 3/8" offset to the body (as measured from parting lines/wind shield to hood opening). Guess will have to line the the stripes to the hood and not the body. Would not suprise me if the fenders are off two.

You guys are great...thanks for the insight and help! Randal

Editing post...Tried Gabriel #49234 air shocks...These things are way too big on the diameter to even come close to fitting in a MKIII. Stratch that idea. Going to adj upper control arms and spring rubbers now.

[ July 25, 2007, 09:09 AM: Message edited by: RandalW ]
 
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