Littlebeefy Posted December 13, 2022 Share Posted December 13, 2022 I'm looking for a part number for a rotor shim that will fit the 5x5.5 bolt pattern. I'm shocked that I can't find one. If anyone has used one to correct runout and knows what it was or where you got it, please let me know. Thanks, Chad Link to comment Share on other sites More sharing options...
85lebaront2 Posted December 13, 2022 Share Posted December 13, 2022 I generally corrected run out by having them turned and if too bad, then replaced. Link to comment Share on other sites More sharing options...
Littlebeefy Posted December 13, 2022 Author Share Posted December 13, 2022 I generally corrected run out by having them turned and if too bad, then replaced. The rotors are new. The high spot moves and changes depending on how I have them mounted on the axle hub. If I rotate them 72 or 144 degrees on the studs I get different measurements. Makes me think the axle hub is a hair off, not the rotor, that's why I was going to try a shim. A shim for a 5 on 5.5 bolt pattern would only be designed for a truck that had rear wheel discs from the factory. Is there a truck that came from the factory with rear discs and a 5x5.5 bolt pattern? Link to comment Share on other sites More sharing options...
mat in tn Posted December 14, 2022 Share Posted December 14, 2022 The rotors are new. The high spot moves and changes depending on how I have them mounted on the axle hub. If I rotate them 72 or 144 degrees on the studs I get different measurements. Makes me think the axle hub is a hair off, not the rotor, that's why I was going to try a shim. A shim for a 5 on 5.5 bolt pattern would only be designed for a truck that had rear wheel discs from the factory. Is there a truck that came from the factory with rear discs and a 5x5.5 bolt pattern? I'm not familiar with a shim to fix this issue. I can understand a shim to locate the rotor within the range of the caliper, but runout means something needs to be fixed not compensated for. unfortunately, the "new" parts are becoming more often the problem. it is possible to find the better fitment by indexing the rotor the way that you describe but it should never be necessary to do so. and that can only do so much. you may even find that swapping left to right may give a better (or worse) fitment. Link to comment Share on other sites More sharing options...
Littlebeefy Posted December 14, 2022 Author Share Posted December 14, 2022 I'm not familiar with a shim to fix this issue. I can understand a shim to locate the rotor within the range of the caliper, but runout means something needs to be fixed not compensated for. unfortunately, the "new" parts are becoming more often the problem. it is possible to find the better fitment by indexing the rotor the way that you describe but it should never be necessary to do so. and that can only do so much. you may even find that swapping left to right may give a better (or worse) fitment. Small amounts of runout can SOMETIMES be resolved with a shim, from my understanding. Look at RAYBESTOS BA10906 for a Dodge Ram, for example. It says it's designed to address up to .006" of runout. If the entire surface of the hub is angled, a shim like this won't fix it. But when you have very small surface inconsistencies (like the size of a human hair), I think this paper shim would be more yielding for even surface mating. In all honesty, tho, I agree with you. I think it should be straight right out of the box. I did find a small steel shim from Baer. It is only 3mm and will give my rotors a little more clearance from the caliper bracket. I'd prefer aluminum but haven't been able to find one. I am using the Wilwood 140-7140 kit that I got from Moser with the custom drilled rotors for 5x5.5. The quality on the stuff is really great. Tolerances are unbelievable. I think my issue stems from the fact that I'm using a chromoly rear axle that is about 3/32" shorter offset. That's why I'm having to use a shim on the rotors. The bracket currently clears the back of the rotor, but the gap is tighter than anything you'd see on a new German sports car. I could pull the axle bearing of and put a small shim on there to give me a little more offset (I know Moser sells them), but I don't think I need to go to the trouble. I'm probably going to try out the steel shim and get the rotor torqued down really tight and try again with the dial indicator. It's my first time doing this, so I will either get what I want or I will get experience... Link to comment Share on other sites More sharing options...
Littlebeefy Posted December 28, 2022 Author Share Posted December 28, 2022 Small amounts of runout can SOMETIMES be resolved with a shim, from my understanding. Look at RAYBESTOS BA10906 for a Dodge Ram, for example. It says it's designed to address up to .006" of runout. If the entire surface of the hub is angled, a shim like this won't fix it. But when you have very small surface inconsistencies (like the size of a human hair), I think this paper shim would be more yielding for even surface mating. In all honesty, tho, I agree with you. I think it should be straight right out of the box. I did find a small steel shim from Baer. It is only 3mm and will give my rotors a little more clearance from the caliper bracket. I'd prefer aluminum but haven't been able to find one. I am using the Wilwood 140-7140 kit that I got from Moser with the custom drilled rotors for 5x5.5. The quality on the stuff is really great. Tolerances are unbelievable. I think my issue stems from the fact that I'm using a chromoly rear axle that is about 3/32" shorter offset. That's why I'm having to use a shim on the rotors. The bracket currently clears the back of the rotor, but the gap is tighter than anything you'd see on a new German sports car. I could pull the axle bearing of and put a small shim on there to give me a little more offset (I know Moser sells them), but I don't think I need to go to the trouble. I'm probably going to try out the steel shim and get the rotor torqued down really tight and try again with the dial indicator. It's my first time doing this, so I will either get what I want or I will get experience... I just want to close this out now that I got it resolved. I ended up getting a 1/8" axle bearing shim from Moser. Had to replace both axle bearings to put it on, but it did move my offset back to stock. I put the Wilwood disc kit on the back now that I have the offset correct and the thing looks and fits great. I'm not sure if it corrected the runout yet (I smoothed the hub face also to clean up the imperfections), but it's as good as it is going to get without new axles so I'll write back once I've got it back on the road (which might be in a couple more months because I'm redoing the front brakes, installing the A/C and upgrading the exhaust). Link to comment Share on other sites More sharing options...
Gary Lewis Posted December 28, 2022 Share Posted December 28, 2022 I just want to close this out now that I got it resolved. I ended up getting a 1/8" axle bearing shim from Moser. Had to replace both axle bearings to put it on, but it did move my offset back to stock. I put the Wilwood disc kit on the back now that I have the offset correct and the thing looks and fits great. I'm not sure if it corrected the runout yet (I smoothed the hub face also to clean up the imperfections), but it's as good as it is going to get without new axles so I'll write back once I've got it back on the road (which might be in a couple more months because I'm redoing the front brakes, installing the A/C and upgrading the exhaust). Thanks for the followup, Chad. I hope that solves the runout issue as well. Link to comment Share on other sites More sharing options...
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