Donnyboy

The Candy Man
Mar 15, 2005
1,558
2
renfrewshire
I've seen a set of hubcentric 5mm spacers for my car that say you don't need longer bolts. I heard some people run 10mm without longer bolts....so would I really need longer bolts for 5mm?
 
imho if you fit 5mm spacers you need 5mm longer bolts, 10mm spacers - 10 mm longer etc etc.
The manufacturer designed their wheels to be held on with a certain length of bolt and fitting spacers obviously reduces that.
Years ago when I was an engineering apprentice the rule of thumb for the depth of a threaded hole was 1.5 times the diameter of the thread ie for an m12 hole its depth must be at least 18mm.
 
I've got 5mm spacers, with no longer bolts.

If you go by the 1.5x rule as stated above, there should be plenty of thread to fit 5mms.

I have had no issues at all since fitting mine, and bolts obviously never come loose.