JK Brake Rotor bolt holes too big?

C

Cadima

New member
Guys,
Messing around on the jeep and I noticed the bolt holes for my brake rotors are much larger than the bolts. It allows the rotor to rotate back and forth on the hub. Never seen that before. Did I get the wrong rotors? I bought the Jeep used so no idea if its stock but its a 2013 JKU with 15K miles on it so should be stock. I guess its not an issue once torqued but still....seems shady.

Thanks

rotor.jpg
 
Not only is that normal, you can tell that you have a factory rotor by looking at the assembly washer still attached to one of the wheel studs. You're fine.
 
wayoflife said:
Not only is that normal, you can tell that you have a factory rotor by looking at the assembly washer still attached to one of the wheel studs. You're fine.
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Yeah I removed those washers while tracking down some front end shimmy. Shimmy went away till I added adjustable control arms and got the caster back from 1 degree to 5.7 degree. Drives much better but the shimmy is back between 55 to 65 despite 3 wheel balance and rotation attempts. I dunno.
 
Cadima said:
Yeah I removed those washers while tracking down some front end shimmy. Shimmy went away till I added adjustable control arms and got the caster back from 1 degree to 5.7 degree. Drives much better but the shimmy is back between 55 to 65 despite 3 wheel balance and rotation attempts. I dunno.
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A speed related shimmy is almost always a balancing issue. Are you running MT/R's per chance? Of the 3 balancing, we're any road force balanced?

5.7 deg of caster will feel nice but will cause drive line vibrations with an aftermarket shaft and or higher gear ratios.
 
wayoflife said:
A speed related shimmy is almost always a balancing issue. Are you running MT/R's per chance? Of the 3 balancing, we're any road force balanced?

5.7 deg of caster will feel nice but will cause drive line vibrations with an aftermarket shaft and or higher gear ratios.
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MTR/K's. The shop with a road force balancer wouldnt put 35's on their precious machine. I watched the tires being balanced and can say that the run-out and weight needed to get em balanced looked really good for such large tires. I do realize though, that you cant truly balance them without a road force balancer. I can tell you that the wheels did not cause any shimmy until I put the new control arms on and got the caster fixed. I did those both at the same time so cant state which change, if any, created the issue or prehaps highlighted it. I find it odd that a shimmy reveals itself without changing anything on the tires, yet blame it on the tires though. It also is odd to have the same shimmy amplitude at the same speeds regardless of which wheels are on the front. There must be other factors interacting here.

I had an Audi and never could eliminate the shimmy in it either, though I did once temporarily by changing out all the control arms. Those arms were chinese crap and wore out within 6 months. I replaced them with good arms, and the shimmy came back instantly. New tires, countless road force balances, new wheels, dial indicators on the shafts, new rotors.....nothing else fixed it. I sold it in great part cause of the shimmy. I am ocd on vibrations. I dunno.
 
Those tires are notoriously difficult to balance. Even though they were touted as the next best thing since sliced bread, there is a reason that you don't see many people run them anymore.
 
Sharkey said:
Those tires are notoriously difficult to balance. Even though they were touted as the next best thing since sliced bread, there is a reason that you don't see many people run them anymore.
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Not sure, they came with it used and I have no other reference. What cant be explained is why the alleged imbalance didnt create a shimmy till I did the control arms, and why its happened twice to me on two vehicles! Bizarre.

My local jeep club has a meeting coming up next week and I am thinking about asking someone to let me borrow their wheels for a quick spin to verify its the wheel/tires.
 
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