Hopefully that sweet title grabbed your attention...
Right down to business. A couple of years ago I fitted some cheap (but not too cheap) Bola wheels to my 135i.
F: Bola B1 18x8.5 ET40
R: Bola B1 18x9.5 ET45
Not "hellaflush" (is that still a thing?!) but fairly wide for the car, it does have some light rubbing on the rears over large compressions. I ran around on them for around 4/5 months then on a long-trip out noticed a nasty rear vibration at speed, it got worse fairly quickly so I pulled over and found this.
At first I thought someone had tried to nick my wheels and got scared off halfway through and left them loose and they'd shaken to this point causing terrible stress on the bolts.
Also this was super fun to drill out
So I bought some replacement bolts, torqued them all to spec and went back to not worrying about it, thinking I was actually lucky to have caught this before it killed me. Skip forward another 4/5 months, same vibration, same sheared/shearing bolts. At this point I'm thinking that either the torque wrench is crap and is massively over/under tightening them (doesn't feel like it on the old bicep torque gauge though). Also I thought it's possible there isn't enough thread engagement so next step. Studs.
So I've converted all four corners to studs with bits from CA Automotive (lovely company btw with amazing staff). Now another 4/5 months go past and this time I'm checking the torque once a month because massive paranoia! Low and behold...
Thankfully snapped studs are a lot easier to extract than snapped bolts so at least they're easier to replace.
So that leads me to here... I'm lost for ideas. They're not too loose (stud spec is 85 ft/lb), comparing the wheel PCD to a spare brake disk, everything looks centered, center bore is correct and snug. I'm at a total loss for why the fixings just keep giving way over and over again. I've spoken to my mechanic (he's utterly confused), the wheel supplier (they've never seen anything like it 25 years of selling bits) and pretty much anyone else who will listen to me ***** about it. No-one has any answers.
I'm open to any and all theories at the moment, but preferably something I can test at home. I'm pretty much at the point of buying a new set of wheels at this stage and just writing off the money lost...
Important notes:
Only ever the rears, never had an issue on the fronts (both sides not just one!)
There is plenty of stud engagement
The studs aren't cheap eBay ones (and neither were either of the bolt sets)
The current nuts are steel (not crap Ebay Alloy ones!)
Final, final (seriously) point:
These should be under very little load, I'm not an engineer by trade but the studs/nuts/bolts locate the wheel, all the forces are on the centre bore, how am I even getting the forces required to snap steel studs is beyond me!
So please, anyone, save my sanity (and wallet!)
Right down to business. A couple of years ago I fitted some cheap (but not too cheap) Bola wheels to my 135i.
F: Bola B1 18x8.5 ET40
R: Bola B1 18x9.5 ET45
Not "hellaflush" (is that still a thing?!) but fairly wide for the car, it does have some light rubbing on the rears over large compressions. I ran around on them for around 4/5 months then on a long-trip out noticed a nasty rear vibration at speed, it got worse fairly quickly so I pulled over and found this.
At first I thought someone had tried to nick my wheels and got scared off halfway through and left them loose and they'd shaken to this point causing terrible stress on the bolts.
Also this was super fun to drill out
So I bought some replacement bolts, torqued them all to spec and went back to not worrying about it, thinking I was actually lucky to have caught this before it killed me. Skip forward another 4/5 months, same vibration, same sheared/shearing bolts. At this point I'm thinking that either the torque wrench is crap and is massively over/under tightening them (doesn't feel like it on the old bicep torque gauge though). Also I thought it's possible there isn't enough thread engagement so next step. Studs.
So I've converted all four corners to studs with bits from CA Automotive (lovely company btw with amazing staff). Now another 4/5 months go past and this time I'm checking the torque once a month because massive paranoia! Low and behold...
Thankfully snapped studs are a lot easier to extract than snapped bolts so at least they're easier to replace.
So that leads me to here... I'm lost for ideas. They're not too loose (stud spec is 85 ft/lb), comparing the wheel PCD to a spare brake disk, everything looks centered, center bore is correct and snug. I'm at a total loss for why the fixings just keep giving way over and over again. I've spoken to my mechanic (he's utterly confused), the wheel supplier (they've never seen anything like it 25 years of selling bits) and pretty much anyone else who will listen to me ***** about it. No-one has any answers.
I'm open to any and all theories at the moment, but preferably something I can test at home. I'm pretty much at the point of buying a new set of wheels at this stage and just writing off the money lost...
Important notes:
Only ever the rears, never had an issue on the fronts (both sides not just one!)
There is plenty of stud engagement
The studs aren't cheap eBay ones (and neither were either of the bolt sets)
The current nuts are steel (not crap Ebay Alloy ones!)
Final, final (seriously) point:
These should be under very little load, I'm not an engineer by trade but the studs/nuts/bolts locate the wheel, all the forces are on the centre bore, how am I even getting the forces required to snap steel studs is beyond me!
So please, anyone, save my sanity (and wallet!)