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Been another year, still going strong no issues to date even on the cheap cheap 25$ bearings. Been auto-xing on 245 RS4's and HPDE on 205 hoosiers. I'm not exactly the best test bed for these things so I'm putting feelers out there for someone who is endurance racing or at least having issues with stock bearings to give these a try. I'm also moving forward with a small run of these things to see what the interest is, it would be nice to have the endurance testing done before their release but honestly at the price point I'll be able to offer these at I don't think it'll matter to the folks who just want to avoid a cracked hub.
(This is the prototype spacer I'm sending to the machine shop to be duplicated, final design will be 1 piece)
Some related notes from our experience racing an E30 in Chump, including many W2W (wheel & wall) impacts with steel wheels. We run 245/40/R15 with full aero/flat bottom, measuring about 1.2-1.5G in flat corners and up to 1.6-1.8G in select high-speed corners with banking (T1/T12 @ Road Atlanta, T1 @ WGI, come to mind). About 2600lb with driver, 57% or so front weight. About 2-300 hrs/year. E30 wheels are offset 0.25'' outboard (-6.35mm), which is about 1'' further outboard than the Miata wheels.
No hub failures or cracks.
I can''t remember the last time we "timed out" a wheel bearing. Easily fine after 50hrs w/o an impact. We just replace them after an impact because we noticed they'd fail (progressively) in the next race or event.
SKF or *** for bearings
We've regularly failed the studs shown in the photos above. Would replace after 100hrs.
Suspected some slipping, torque wheels to 100 ft lbs now.
Thanks for the data point and stud suggestion. Seems Vorshlage and others use a stud with much less of a shoulder, I can definitely see how that would be more crack prone but it does seem like you would need wheel slipping to cause it.
Can you describe the hub failures you've seen? I assume it's a noisy bearing and not catostrophic coming apart.
Thanks for the data point and stud suggestion. Seems Vorshlage and others use a stud with much less of a shoulder, I can definitely see how that would be more crack prone but it does seem like you would need wheel slipping to cause it.
Can you describe the hub failures you've seen? I assume it's a noisy bearing and not catostrophic coming apart.
Yes, exactly. For periodic inspections, which are usually conducted during rotor replacements, we'll slowly turn the hub and feel/listen for variations in resistance indicating contamination or damage. Some resistance is expected, especially on a new bearing, but it should be smooth and even throughout the rotation.
We bough a corner with the $5-7 studs once from an old Spec E30 in a rush after breaking a LF strut in half (take care with your reinforcement geometry...) at Road America. The first test session with the new strut resulted in multiple broken studs on that corner. Driver came in complaining of vibration...we were running the kink, could have been bad..
Maybe a dumb question, but couldn't you drill the hubs and press in ARP studs? I'm not sure if ARP studs are long enough to clear the spacer. If not, could the caliper brackets be shimmed to move the disc inward to allow for the thinner spacer? Just thinking off the top of my head to remove what is possibly the remaining weak link.
Edit: I just noticed that the caliper brackets are on the outside of the knuckle.
Think you're overthinking the perceived problem. Cwatson is literally hitting stuff with his car and reusing the good studs on the next hub that's saying a lot for the bimmerworld studs. It's standard operating procedure to replace bearings, studs and all, after contact. Drilling and pressing in ARP studs would end up costing more than the better studs by a long shot,
Good news, finally found a machine shop that will take on the spacers in the quantity that I need. Prototype is off to the other side of the country for measurements. He seemed very confident this would be no problem since they specialize in custom wheel spacers. I'm going to commit to a batch of 10 sets to get these out in the world.
Mods.....let me know what needs to happen for a group buy.
It's just about time for a set of front hubs for the toy car. I would be interested in a set, but I don't actually get much track time in or time to work on the car, so would be bad for testing. I can sit out on this and make my own spacers if you want the first group to be testers.
Think you're overthinking the perceived problem. Cwatson is literally hitting stuff with his car and reusing the good studs on the next hub that's saying a lot for the bimmerworld studs. It's standard operating procedure to replace bearings, studs and all, after contact. Drilling and pressing in ARP studs would end up costing more than the better studs by a long shot,
Good news, finally found a machine shop that will take on the spacers in the quantity that I need. Prototype is off to the other side of the country for measurements. He seemed very confident this would be no problem since they specialize in custom wheel spacers. I'm going to commit to a batch of 10 sets to get these out in the world.
Mods.....let me know what needs to happen for a group buy.
Just received an ETA from the machine shop on the pilot run of bearings, should have them in 2 weeks. Once I can confirm the quality and fitment is there I can finalize costs.
02-26-2019, 10:00 AM
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