This past weekend I ran my first autocross of the season with Detroit Region SCCA. It was also my first GS event after selling my 2003 Cooper S and replacing it with a late 2006 Cooper S. Unfortunately, I ended up running on my street tires.

In paddock prior to the event I jacked up the car and attempted to mount my old race wheels (shod with new Kumho 710 rubber) on the new car. Surprise! It looks like for 2006 MINI opted to change the lug bolt size. New bolts appear to be 1-2 mm larger in diameter than those on my old 2003. Result is that although the hole centers are in the same spots, I can't get the new bolts through the bolt holes on my old wheels.

Surely others must have run into this problem before -- maybe some of you guys with the new 2007 too? What are possible solutions? Could I use a tap set myself to increase the hole size in my wheels to match the new bolts? Other ideas? I really don't want to spend a bunch of money to replace the wheels and/or dismount and remount plus rebalance these tires. At the same time, I don't want to do anything stupid (unsafe).

 

there are stud conversions that should do the trick for you

 

heres a link to the conversons.
http://www.txwerks.com/servlet/Categ...el+Accessories

 

Coincidentally, I found the same problem when I tried to fit the race and aftermarket street wheels from my '03 Cooper to my '06 Cooper S. My solution was to simply drill out the holes with a proper sized bit. My take is that the taper holds the wheel and the bore itself is not critical. Very little of the taper is lost when upsizing. In any case, my race wheels have completed more than thirty autocross runs and my street wheels more than 5000 miles with no problem. Remember that the torque for the larger bolts is 104 ft.pds.

 

I've got the same problem with my Konig Heliums I had for my '05. I just plan on going to Lowe's or Home Depot and getting a nice 5/8" bit and do some drilling.

 

All --

Thanks for the suggestions -- both the converters and the thought to just drill out the bolt holes.

* Concerning the converters, I've read elsewhere that studs may not stay securely attached to the MINI's wheels. Any reaction, or first-hand experience with this?

* For anyone who has drilled out their wheel holes, did you do any sort of fixturing or setup to try to ensure that new (wider) hole retained the same vertical axis of the original hole? Seems reasonable that the drill would tend to follow the axis of the original hole (i.e. it would self-align), but I don't know that for certain. Obviously, I'd like to avoid an expensive mistake if I can. That's why my original thought was to use a tap set to slowly/carefully enlarge the holes, then once they were large enough I'd use a drill bit to remove the thread material, hopefully leaving only the outside hole diameter.

 

I can understand your hesitance to drill out the holes, but consider this. The bores in the wheel are alread oversized so that the bolts will slide easily into the holes (or the wheel over studs if they are used). The wheel is not supported by the bores. FWIW, I used a hand drill and slowly let the bit follow the existing hole. Of course, your plan to use a tap would also work.

 

Have about 8K miles on the TSW studs. This includes 3 track days, 1 AutoX and spirited driving on the The Dragon. When installed I was generous with the Red Locktite. No issues what so ever and I change wheels/tires between 6 different sets with at least 1 swap a week. TSW recommended a very light coating of anti-seize on the studs. The only problem with that is the stuff is messy.

 

I have the Texas Kit, http://www.txwerks.com/servlet/Detail?no=47 and had no prob with them. I checked them after about 200 miles and got less then a quarter turn out of 2. checked after that and they are good, I just put about 2000 miles on them with this trip to the dragon.

 

I simply used a step-style drill bit and went slow. I had to drill from both sides to make sure I didnt make the hole too large. Then smoothed the centers with a 1/2" bit. Works fine now.

It turns out though that I might have to switch to those conversion studs as I'm probably going to be using spacers for racing...oh well.