How do I measure for adapters?

[DarkoNova]

I'm going to be ordering disc brakes in the next few days and I'm just wondering how I'm supposed to measure for the adapters to get these 8" wheels to fit without rubbing. They're BMW M3 wheels and I'm trying to get them on my 69 Nova.

Any ideas?

Matt

[bochnak]

http://www.skulte.com/adapterfaq.html

[hardline_42]

I highly suggest going to www.wheeladapter.com and speaking directly with Fred Goeske. He has done all of my wheel adapters and I can't say enough good things about them. To know how thick the adapters need to be, you need to measure the maximum backspacing your suspension will allow you to run. Then, figure out the backspacing of the BMW wheel and subtract one from the other. Make sure you include the thickness of slip-on rotors etc. when you do your calculations. A few things to keep in mind:

1. The adapters need to be HUBCENTRIC to the hub/axle flange and WHEELCENTRIC to the wheel. Any decent adapter manufacturer should know the dimensions for the hub side but you will need to get a measurement of the wheel center for the wheelcentric lip.

2. The BMW pattern is slightly different from the GM 5 on 4.75" pattern. Your wheel adapter manuf. should know this.

3. Upgrade to ARP wheel studs. Even though the design of the adapter effectively makes one solid connection, it's cheap insurance to replace the hub/axle studs with larger, better quality ones. Make sure the adapters come with upgraded studs. Again, it should be included in any quality set of adapters.

4. Expect to pay more for a quality set of adapters. A set of (4) 2.25" adapters w/ everything I mentioned above ran me $375 shipped (only $25 less than the 'vette replicas they were going behind!). Of course, you get what you pay for and wheel adapters is not a place to skimp. Be wary of any eBay or lower priced adapters that are either off-the-shelf items or aren't custom made for your application.

[DarkoNova]

See I've read a few pages on it already, but none of them really tell me anything I don't already know. Like how do I figure out the maximum backspacing I can run?

The problem with the instructions I've read is that you're "supposed" to measure the backspacing on your current wheels and use that to compare to the new wheels. My wheels, however, rub at full lock on both left and right turns. There's no marks on the frame or the inside of the fenders so I have no clue where the hell it's actually rubbing. :dunno:

I already planned on getting Skulte adapters, so I know they'll be slightly expensive, but like you said, wheel adapters is one place I won't be skimping.

Matt

[MrQuick]

Hey Matt,

well the adapter/spacer is going to take or make up the space you need to obtain the proper back spacing. I like to mount up the rims with tires mounted and use cheap spacers stacked so I can temporarily drive the car in our parking lot then check for clearance. Go into drivways,go over bumps and such. Then I measure the spacers used then order. My source custom machines the adapters to the specs I send them.

Depending on the car you own there should be a known back spacing distance.

Measure the back space you have on the rims you want to use.

Now subtract the known good number from the actual rim back space and this will give you the desired adapter/spacer size.

Remember to measure your hub circumfrence and the rim hub opening to get the proper hub fitment.

[LateNight72]

nvm

[Boulder69]

If you already have the wheels and brakes and just need to measure for the adaptors to make it all fit right you may want to try something simple - just use a bunch of heavy duty washers between the rotor and wheel for mock-up to get it dialed in. Obviously you can't drive it with the washers but you should be able to load the suspension and check lock to lock no proby.

Just a thought.....