Minimum number of wheel nut rotations
Discussion
Having some 'fun' with some aftermarket wheels. Got what is probably a dumb question but after an hour of trawling the web i'm no closer to working it out.
Basic problem is i'm concerned there's insufficient thread showing on wheel stud to put enough rotations on the wheel nut to secure the wheel.
Best guidance i've managed to find is that MSA regs state minimum rotations as "1.5x the diameter of the stud". What i'm not sure of is the stud diameter or what unit should be used to measure it for the multiplier.
Stud is M12x 1.5 (I think). I believe the 12 indicates a 12mm diameter? So what does the 1.5 mean? (Is it the multiplier for the head size (12x1.5=18mm head?) or something else? [Edit, further investigation done - I believe this may be the thread pitch so thread pitch is 1.5mm?]
If i'm right about the 12mm then number of nut rotations is 12x1.5 which is 18, which is too many to make any sense.
The alternative is i'm completely misunderstanding the whole thing and "1.5x the diameter of the stud" has nothing to do with the # of rotations and could refer to the length of stud that should protude from the wheel for solid engagement. So 18mm. In this case where how to measure this accurately?
If you hadnt guessed, i'm confused as fook so all help appreciated - i'm tired of spinning my nuts!
Basic problem is i'm concerned there's insufficient thread showing on wheel stud to put enough rotations on the wheel nut to secure the wheel.
Best guidance i've managed to find is that MSA regs state minimum rotations as "1.5x the diameter of the stud". What i'm not sure of is the stud diameter or what unit should be used to measure it for the multiplier.
Stud is M12x 1.5 (I think). I believe the 12 indicates a 12mm diameter? So what does the 1.5 mean? (Is it the multiplier for the head size (12x1.5=18mm head?) or something else? [Edit, further investigation done - I believe this may be the thread pitch so thread pitch is 1.5mm?]
If i'm right about the 12mm then number of nut rotations is 12x1.5 which is 18, which is too many to make any sense.
The alternative is i'm completely misunderstanding the whole thing and "1.5x the diameter of the stud" has nothing to do with the # of rotations and could refer to the length of stud that should protude from the wheel for solid engagement. So 18mm. In this case where how to measure this accurately?
If you hadnt guessed, i'm confused as fook so all help appreciated - i'm tired of spinning my nuts!
Edited by redseal on Thursday 16th August 10:07
M12x1.5 mean that the thread is 1.5mm pitch (ie one thread every 1.5mm).
1.5D is reasonable standard thread engagement but I would be happy running 1D and checking them regularly.
So for 1.5D that would mean 1.5*12/1.5=12 turns, for 1D that would be 1*12/1.5=8 turns.
1.5D is reasonable standard thread engagement but I would be happy running 1D and checking them regularly.
So for 1.5D that would mean 1.5*12/1.5=12 turns, for 1D that would be 1*12/1.5=8 turns.
Edited by Adam205 on Thursday 16th August 10:06
Simple answer
Look at where the thread engages in the hub and measure the depth to the back of the thread.
Now poke the bolt through the wheel and see how much comes out the back.
Provided the thread on the bolt is sufficient for full engagement in the hub you have the maximum possible strength available to hold the wheel on.
Any less is losing strength, any more is superfluous to requirements & could even foul something behind the hub.
Look at where the thread engages in the hub and measure the depth to the back of the thread.
Now poke the bolt through the wheel and see how much comes out the back.
Provided the thread on the bolt is sufficient for full engagement in the hub you have the maximum possible strength available to hold the wheel on.
Any less is losing strength, any more is superfluous to requirements & could even foul something behind the hub.
Gassing Station | Suspension, Brakes & Tyres | Top of Page | What's New | My Stuff