TIme to get some new wheel bolts other than the OEM alloys. Question is what shank length. There are a couple of threads that discuss the overall OEM bolt length but all replacements focus on the shank, e.g. stock bolt length is 45mm, extended bolts w/5mm spacers are 50. Unfortunately replacements, e.g. GMP, RAD, etc, list by shank length and seem to disagree on the appropriate shank length for a given application.

Case in point - I have the factory 5mm spacers and associated bolts. Speaking with folks at RAD they suggest a 32mm as optimal, GMP says 37. A 5mm spread seems pretty wide, last thing I'd want would be contact on the backend of the hub.

 

Are they recommending a shorter bolt? Your incorrect that the worst thing is the bolts too long, worst is bolts two short and loosing your wheel at 60mph+ on the highway...

 

They're not recommending a shorter bolt - both aftermarket bolts are longer than the OEM non-spacer bolt, the challenge is that there there's an inconsistency in what the correct bolt would be in the given configuration with both sources being highly reliable.

No debate on what's worse - too much delta in either direction means disaster.

 

stock 911 bolts arent 45mm.
stock is 30mm, for +5mm spacer would be 35mm bolts, + or - 2 or 3mm would be ok
common 7 to 8mm spacer on front use common 38mm bolts
common 15mm spacer on rear use common 45mm bolts

 

Rule of thumb..........1.5 x bolt dia = required thread engagement for steel bolts in steel thread bore. That's what we use at the big yellow tractor company with grade 8 bolts.