Everyone,
Here is what I'm submitting to the builder of MSP's hubs along with pictures of the removal (nut, spindle, caliper/bracket, ball joints) & the failed hub itself. These were their 'enduro' hub with the long studs (2.25") installed. It's my understanding MSP has halted the sale of these pending the builder's review of the two failures they've received (mine & another's).
- Installed hub, torqued to 140#, installed nut cap w/silicone
- Installed new Carbotech XP12 pads & rotors
- Installed Toyo R-888 (<4/32 depth; unknown HCs) on +30mm wheels with a 5mm spacer
Loaded onto trailer (open) using tow hooks at front & subframe brace attachment point in rear (along side the differential); crossed tie-downs both F&R; not "cranked down" and the car will move counter to the trailer over bumps. Drove to NJMP from north Jersey (2.5 hours, all Interstate/2-lane highway); easy tow mostly at 75MPH.
Friday was a test day (20 minutes each); here are the session summaries.
- Brake pad/rotor bedding; no offs or impacts, easy laps (mostly 1:39s)
- Low 1:38s, no offs or impacts, paddock tire pressures were within range (32.5-33.8)
- Same as #2
- Switched to Toyo RRs (~5 HCs), 1:37.5, paddock tire pressures were within range (37.1-38.7); no lockups or impacts
Saturday was a qualifying & race (still on RRs).
- Qualified P8 w/a 1:37.0; may have had 2x 4-wheel offs (to the right; left-hand turn); I left the paddock tire pressures too high (+1.8-2.2) so no post-session impound pressures were taken
- Race finished P6 with lots of low 1:37s; forgot to take pressures in impound
Sunday was a qualifying & race
- Qualified P3 w/a 1:36.5; did not take pressures in impound post-session but discovered a chunk of tread removed (directly to cords) at the tread seam.
- Race on SM7s (~5 HCs); finished P6; absent hub failure it might have been P3. A lap 1 wreck (row 3 or 4) on front straight put us in the mix with a lot of faster cars so I was fighting with ITR/ITS cars throughout the first half of the race
Upon removal of the hub there was a distinct "suction" of the nut cap to the hub that was unusual. IOW, there was negative pressure inside the hub sucking the cap back until I was able to pull it far enough away to suck in outside air. This I had not experienced ever before (good seals in these hubs I guess?).
The grease in these hubs is stinky! Additionally the grease had been thrown all around the nut faces & the inside of the cap. There was also grease thrown from the rear side of the hub onto the caliper bracket but none appeared to be on the inside edge of the rotor.
Looking down the bore of the hub I observed the gap between the two inner races, to me, looks to be a lot narrower relative to my other hubs but I did not take any measurements pre/post installation of either style (MSP or personal). I'm suspecting the balls are smaller in diameter which enables this gap to be narrower.
That's about it for my observations and documentation of the car & sessions. I'm at a loss to explain the failure considering my past experiences. Granted I've been getting faster than the 4 previous seasons and so may be "using" more of the car's capabilities which is translating into parts wearing faster (I went through 50% pad thickness on those XP12s!!!). However in my opinion that could not explain a $225 part failing before completing a single double-race weekend + test day.
Here's hoping they're able to identify something that will make these a worthwhile investment!
Brandon