Hey Everyone,
I have a question and need some expert advice... I recently converted my 9" drums over to the 10". The conversion went great. What I have run into is this....the 10" drums are the finned style with an outer ridge that creates a 'concave' area around the center of the drum and studs. So, when you mount the Cragars, the wheel spokes ride on this ridge and won't let the center of the wheel mount flush. After tightening the wheels down and driving it, you of course get a great amount of 'shuddering' from the drums since they are getting torqued out-a-round. I removed the wheels and added some extra lug nut washer's around each stud. It took two washers per stud (approx. 3/16") to fill the void behind the wheel. These spacers were able to just barely lift the spokes of the wheel off of the ridge. After tightening and test driving, the brakes work smoothly with no shuddering. Question: By adding these washer 'spacer's around the studs, am I creating any structural problems ? Obviously, there is still a void elsewhere behind the wheel center except for the surface area the washers take up. Is this too dangerous to drive with this setup ? I am thinking of calling around to some metal fabricators and have them make up a solid plate that I could slip over the studs that would be the same diameter as the wheel center and fill in the void. Are there any products in the Autoparts stores that would satisfy this problem ? Thanks for your thoughts, advice, and ideas...!!
66Dart

Washers are not safe to use as spacers, according to just about every book on handling that mentions spacers. You can get off the shelf aluminum spacers, but they're usually somewhat imprecise. I am using those currently on the rear of my Dart. For maximum precission, you can get a block machined that centers itself on the raised part at the center of the hub, and centers the wheels on that section.

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Matt has it right here. Stay away from washers. I have a set of Mr Gasket spacers on my 16X8 Mustang wheels, but the rears lose the hub centering of the axle, so I will eventually make up some hub centric spacers.

Lou

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Home of Slant6-powered fun machines since 1988

Are you having any vibration problems from running without hub-centric spacers on your Dart? I haven't hit the street with my setup using spacers on the rear axle, and I was wondering if I was in for some more noise, vibration, and harshness (it's bad enough with a glasspack and very racuous electric fuel pump...).

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"Mad Scientist" Matt Cramer
'66 Dart - turbocharged 225
My blog - Mad Scientist Matt's Lair

Matt & Lou,
Thanks for your replies and thoughts. In the past (9" flat faced drums) and currently, the Cragar wheels have never used the hub as a reference to centering. As the long stemmed lug nuts go through the wheel (very tight clearance) and onto the studs, this is what aligns the wheel to the drum and allows zero tolerance for wheel movement off-center. The hub does not provide any centering. For now (temporarily) I purchased some 2" diameter flat washers that go around each stud and pretty much fill the void within the concaved mounting area. The way the Cragars are made and the contact mounting surface the wheel has around each stud, these larger diameter washers provide a greater amount of torque distribution. Any other thoughts or ideas..? Thanks alot guys
Matt Simpson (66Dart)

Matt Cramer - no problems with wheel vibration that I can tell. Tested up to 125 MPH so far. I do have a little driveshaft vibe, but not too bad. My fronts are hub centric due to a coincidence with the Mustang center hole and the diam of the 12" Mopar disc hubs further away from the flange, but the rears are not.

My car pulls harder at high RPM with the Megasquirt EFI controller, so I am interested to see just how fast this car would go. Might have to get into one of those open road challenges and crank it up. 140 MPH is quite doable I think, and probably faster.

Matt Simpson - Unfortunately, I think those Mr Gasket spacers won't work with small bolt pattern. Maybe your 2" diam washers are the best way to go? Otherwise, you'll probably have to make some spacers. Maybe cut the centers out of your old 9" drums??

Cheers,

Lou

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Home of Slant6-powered fun machines since 1988

I was running a set of 7" wide slots on my dart for a while and the inside edge of the wheel just touched the upper control arm. So I just went to the local tire and wheel shop and got a set of aluminum spacers. Bolted them on and away we went. I can't remember exactly how they fit but I didn't notice any vibrations? I do remember the holes not being round though. They were kind of flat on the sides.

Rick

Matt, I just had the same problem recently when mounting the Aluminum slots on my Scamp with finned drums.
I searched everywhere, went to machine shop & etc. with no luck. I went to the local speed shop and got a set of 1/4 spacers that are 6" in diameter. The holes are slotted and you will have to elongate a couple of the holes to match up for your 4" bolt pattern.
I then epoxied the spacer to the drum and also use a grinder to machine off the high point of the fins where the wheel was touching.
It now fits great, will mount smoothly and rides perfect.
And, it only cost me about $12.

Just find a store close by that sells custom wheels and look for the spacers.

Thanks for all the comments and suggestions everyone.

MMSC...I'll try some of the wheel shops here around Portland and see what I find.

Thanks Again