dimented24x7

iTrader: (2)

Picked up some new rims for my Camaro: http://www.summitracing.com/parts/ma...513b/overview/

Of course, since there aren't too many rims on the 4.750" bolt pattern I bought 4.500" patter instead, along with 1.5" adapters. Seemed easy enough, but the extra spacing put the offset a tad too far out for the front with my usual 225/55 or 225/60 tires I like to run (yeah fat tire I know, but the roads here suck) so the fronts kept rubbing the fender liners.

To fix it I decided to drill a new bolt pattern in some spare rotors myself so I could eliminate the spacers up front. Might seem a bit crazy, but it wasn't so bad, and it provided a Saturday afternoon fix for the front to get rid of the adapters there. Still have them in the back, but not sure if I want to make this permanent at all four corners yet. Also obviously would have to do this for each new set of rotors as well.

To do it I used a pattern template I made up in CAD using Creo. Then cut the pattern out with hobby scissors and then used a 12mm arbor punch to cut out the 4.750" holes to locate the pattern off of the original lugs. The new centers for the 4.500" pattern were marked on the template so I would know where to punch. When locating the pattern, I had to be sure to miss anything structural behind the hub face, so I offset the pattern 20 degrees from the original to fit. Then it was onto centering the template, pasting it on, and punching the new locations with a center punch.

Next the tooling. Needed 1-2-3 blocks, 31/64" drill bit, center finder, and a 23/32" counter sink with pilot, in addition to your basic drill press. In this case a cheap sears one. The tooling is cheap from MSC if you want to slum it, with the exception of the countersink bit. They had a cheap import, but raw cast iron can be pretty nasty stuff to machine.

Locating the holes required some care since that is what sets the ultimate accuracy. Using a center finder made this much easier rather than using laser cross-sites or measuring since the max out of position tolerance is only about .005", and those would be too imprecise on a bare bones drill press.

Once located the holes can be drilled. Once they're done, flipped the rotor over, mounted it on the blocks, and put in the counter sinks for the studs. These are important as well since they have to be perpendicular to the hole for the stud, or it may sit ****-eyed.

To install the studs, I used a large metric 12.5 x 1.5 nut and washer to pull them in, but a hydraulic press could also be used.

dimented24x7

iTrader: (2)

When all was said and done, the studs were all within .005" radially of the true positon for the new pattern. The group positioning was off on one rotor by about .010" radially, but the resulting run-out is inconsequential compared to a tire which is about 10x worse. If I have to do it again I would have a shop make up a physical punching template that locates off of the hub boss instead so I could ensure that they are truly centered on the rotor hub, but printer paper and toner were a helluva lot cheaper and readily available .

I may yet just put skinny tires on and go back to spacers when the rotors wear out, but the new tires do have a nice ride. Much better than the dinky little 15's that were on there. Plus its nice to not have to worry about potholes taking out one of the tires.

LAFireboyd

iTrader: (3)

Thought about changing pattern, too, when shopping for new wheels. Found drill guides from Rotten Leonard www.rottenleonard.com . Would've worked great for the front rotors, like you did, but because of all the extra holes in the 9-bolts hubs, drilling the rears would've been risky, maybe even impossible. So i went with adapters.

But with the drill guide from Rotten Leonard, at least it makes changing patterns simple, opening up more wheel options.

dimented24x7

iTrader: (2)

I have a 9-bolt as well. I have spare axles, but to do them would require dropping them off at a competent shop to have the existing holes welded, hub refaced, and new holes drilled. The large holes for accessing the retainer plate bolts take away a lot of material like you said.

liquidh8

Old thread I know, but thank you for sharing. I am having some similar issues. I am using 5 x 4.5 wheels on my g-body wagon. I was running 17x8 with a 245/45/17 on the front. I picked up new wheels, again, 5 x 4.5, but this time 17x9, same size tire.

It appears I may rub the lip in front. I am running a 1.25" adpater, just ordered some 1" for the front. But I just toady found that rottenleanard drill guide. I may but those and try that out with some .50 or whatever spacers to get the wheel right.

Anyway, just wanted to say thank for sharing.

fullsize fun

I highly doubt there is a shortage of 5x475 bolt pattern wheels , They are common as dirt.