Hello everyone...

Let me say at first that I don't have a mini...but, I'm hoping someone here can help since it seems of lot of people here have performed the lug bolt to lug stud conversion.

I need to do this on a small travel trailer as I have lug bolts but I need lug studs for some different rims. My question regards how far the stud screws into the wheel hub. I know that some people here reported that their studs went in as far as their lug bolts did, but that doesn't help me since I don't have a mini ha ha...does this mean they hit the back of the hub and stopped, did they reach the end of the actual threaded area of the hub (I don't know the specifics of a mini's hubs) and stopped, or did they stop when they reached the smooth area of the new studs?

My trailer hubs have bolt holes that are about 1.5 inches deep; my original lug studs don't go in that far, but they definitely go in 5/8" to 3/4". So, my question to those of you who have physically used these studs is...do they screw in until they hit the back of the boared hub bolthole, or do they stop when they hit the smooth section of the new studs? And, if so, how much past the smooth section on the new studs do they go in??? The pictures I have seen of my particular stud that I need (1/2" X 20) definitely look like there's just not enough stud going into the boltholes. How far would you accurately estimate your studs go into your hubs? I really must know...

Thanks everyone for helping out a "non-mini'er"!!!!

Jeff

 

The rule is that for full strength the length of thread engagement needs to be at least the same as the bolt diameter. (Past that there's no additional strength.) It's easiest to gauge this in terms of how many turns of engagment you get.

Let's use an example. The Mini uses M12x1.5 lug bolts, which translated means that the nominal bolt diameter is 12mm and the thread pitch - the distance between adjacent threads - is 1.5mm. So to get the required full 12mm of thread engagement you'd need 8 or more turns (8 x 1.5 = 12). The hub should be thick enough to allow at least that many threads.

That same logic also applies to wheel studs used with lug nuts. In addition to having full stud engagement in the hub, each stud needs to be long enough for sufficient thread engagement in the lug nut.

Depending on the installation you may also need to be careful about excess stud length in the hub. For instance my BMW has a fairly limited clearance behind the front hubs, so screwing in too much stud or lug bolt length could cause the inner end of the studs to hit non-rating parts behind. Not a good thing! Many studs have a non-threaded band at the right distance in from the inboard end to prevent them from being screwed in too far.

Hope this helps.

Neil
05 MCS - stock lug bolts
96 M3 - studs

 

My studs have a non-threaded portion so the stud can only go in so far. I didn't measure it but I'm sure its not more than 1/2 inch. Don't forget to use loctite.

 

And be sure to get the torque value for the install... studs on my MINI were inserted and loc-tite'd at a much lower torque than the 86 ft-lbs that I used for the lug bolts