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Topic of the Day - converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Tom C ()
Date: March 04, 2005 09:21AM

I've been searching for custom wheels for my '63 and I just don't like the styles of the few choices there are out there. So, I'm thinking that my alternative is to convert my EM to a 5 bolt pattern.

Do any of the Corvair related books tell you what to do?

If not, what are the steps involved?

Tom C

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converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Steve O ()
Date: March 04, 2005 10:38AM

Tom - "easiest" way to change the front is to install a late model cross-member, complete with all the suspension hardware and hubs. I believe that installation results in a slightly wider "track", but it will give you what you are looking for.

For the rear, the "easiest" way is to have the hubs re-drilled with the 5 bolt pattern. Some people have also installed forward control axles, but since the FC axle is longer than the car axle, you end up with a significantly wider track. If nothing else, it "looks" funny...go with the redrilled hubs. I don't know of any vendor doing that work at present - make a deal with a local machine shop.

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Re: converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Tom C ()
Date: March 04, 2005 11:10AM

So is it not wise to re-drill the front drums/hubs as well?

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Re: converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Matt N. ()
Date: March 04, 2005 11:46AM

Yes you can weld / drill all 4! I do them myself.

Pull the rear axles . front hubs Drums remove studs [save!]

Get a LM brake drum for a pattern....

Weld / JB weld ONE [1] hole in each hub. Grind smooth

Using the LM brake drum scribe /centerpunch the 5 holes

Drill as straight as you can, preferable with a drill press..but a BLOCK of steel drilled in a press is good as a guide

REMEMBER the studs are "interference fit" so the hole is slightly smaller.

The use a LM drum is best because it centers the holes..and tires are RUBBER...so 0.010" means nothing...but be as precise as possible.

Remember..the wheels studs "CLAMP" the wheel. The center HUBRING holds the weight..design wise!

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Re: Topic of the Day - converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Tom C ()
Date: March 04, 2005 12:49PM

I just found 3 wheels from American Eagle Wheel that look like they will work. Let me know your opinion on which looks best. Here they are (poor MS paint editing) superimposed on my '63.

original
[pics.bbzzdd.com]

Series 188 - 4 on 4 1/2, 14x6, 4 11/16 backspace - I guess a spacer will be needed
[pics.bbzzdd.com]

Series 192 - 4 on 4 1/2, 14x6, 4 11/16 backspace
[pics.bbzzdd.com]

Series 172 - 4 on 4 1/2, 14x6, 4 9/16 backspace
[pics.bbzzdd.com]

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Re: Topic of the Day - converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Tom C ()
Date: March 04, 2005 12:55PM

OK, now the fixed links

original
[pics.bbzzdd.com]

Series 188 - 4 on 4 1/2, 14x6, 4 11/16 backspace - I guess a spacer will be needed
[pics.bbzzdd.com]

Series 192 - 4 on 4 1/2, 14x6, 4 11/16 backspace
[pics.bbzzdd.com]

Series 172 - 4 on 4 1/2, 14x6, 4 9/16 backspace
[pics.bbzzdd.com]

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converting EM 4 bolt pattern to 5 bolt pattern
Posted by: Steve O ()
Date: March 04, 2005 01:36PM

Tom - check the hub opening of those wheels also - sorry, I don't know the opening required, but I think the Corvair hub center is larger than the opening on many new wheels.

With a 5/16" to 7/16" spacer, at least on the front, those wheels "should" work - assuming you're defining back spacing as Bryan Blackwell has done. It's going to depend on the tire you choose and on how much hammer work you want to do to your front inner fender lip. At the very least, you'll have to turn it up slightly - not hard to do with a small sledge hammer.

The worst interference problem will be on the left front. Make a deal with the tire shop that if your choice of wheel/tire doesn't fit, you're not going to buy it. You'll really just have to try some combinations.

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Re: Topic of the Day - converting EM 4 bolt pattern to 5 bolt pattern
Posted by: steve goodman ()
Date: March 04, 2005 10:08PM

Hello Tom: The best reason to just change the front for LM is the larger brakes on the front. You can just swap spindles and then the backing plates and drums also but then you lose the ability to have a nice sway bar on the front.

OR you can use the LM disc brake kits for 14" easier.

Someone was adapting the LM drums on the rear a while back using the stock car axles but I don't recall reading how their progress is going. Hopefully they will see this and post a note.

Regards, Steve

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