OEM Wheel Bolt Length

[LittleT]

Afternoon All... Just had a new tyre fitted and the fitter advised me the studs are way to short...they only go into the hubs 2.5 turns and reckons this should be at least 5/6 to be safe.
You can see in the image where the thread goes into the hub ..
Any advice would be helfull and put my mind at rest..

 

[AdL]

I don't know what the spec for this is - but as an engineer I would be serious worried about that. I think I read somewhere that thread length should be at least the same as the bolt diameter.