I have wheels with 12mm lug openings.

OK i've explored the 14-12mm stud conversion kits and there are aspects of the kit that I'm not thrilled about. (longer stud length than what i need, use of open ended lug nuts, 1/2" of exposed threads).

Second option is to bore out the existing openings to 14mm. How do you go about doing this and what kind of shop would be able to handle this task? Thanks.

 

Any competent machine shop can do this for you. The is more then just making the hole larger, need to make sure the seat is also machined to accept the lug.

 

Sometimes they fit just fine. .472 = 12mm. .551 = 14mm
If they are tapered seats, it is the taper that controls the placement.

What you need is a reamer with a smaller starting taper. Possibly a 13mm and a 14mm depending on the taper, or a step reamer (more money)

I'd be concerned if you had to actually cut down the taper very much as it could weaken the wheel.

http://www.toolcribdepot.com/WebShop/reamers/R106.asp

 

Thanks for the responses.

I called the wheel manufacturer, well actually the US distributor of my wheel and i was told that I could bore out the holes to 14mm, and do it from the backside of the wheel. To just make the holes slightly bigger than thread diameter so the threads don't touch the wheels and that there would still be enough of the original taper, 60 degree conical seat that there wouldn't be a safety issue. You guys agree? Oh speaking of 14mm lug bolts, are the OEM bolts 60 degree conical or do i need to find new ones?

 

Almost all lug bolts are the 60 degree, make sure that you have enough bolt going into the hub with the new wheels. Being a 14mm bolt it needs to go into the hub at least 14mm, so when you feel the threads grab and start to hand tighten the bolt should go in about 9-10 complete turns. I had this issue on a set of BBS RV-F and we found the 28mm factory bolts are about 5mm too short so had to find and buy longer bolts. If this is the case PM me and I'll send you the info. There are only two MFG of the 14x1.25 bolts.

 

Ok, I'll admit it. I ordered a new set of wheels a while back, and didn't even think about the difference in lug size until the new wheels arrived. Well wouldn't you know it, the bolt holes were 12mm and mine lugs are 14mm. I thought about sending them back, but there would have been shipping charges of $50 plus a restocking fee of 15%. So I decided to do a little research here on NAM. Sure enough, I found quite a few folks who had simply bored out the 12mm holes to 14mm holes. So, I thought about it a few days and decided to give it a try.

I went to Lowes and bought a GOOD and SHARP 9/16 inch bit (not your typical $2 bit). I carefully drilled from the front side of the wheel with a variable speed drill. I took my time and it was a piece of cake to do. If I didn't tell someone what I had done, they would never know by looking at the wheels.

My wheels are aluminum. I wouldn't try it on steel wheels, or chromed wheels.

If you do decide to have the wheels bored out, make sure that the head of the lugs you plan on using will fit into the factory bored holes on the wheels. Unless you use a "tuner style" lug bolt that uses the hex bit to tighten them, your lug bolts may not fit into the holes on the wheels.

It can be done. I've ran my wheels about 5,000 miles with no problems what so ever. If you drill, take your time, use a NEW bit in a variable speed drill and you'll be alright.