Thread: Centerline Convo Pro wheel issue

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My brother just purchased me a set of Convo Pros for my Corvette for my birthday! Today the fronts arrived and I noticed the hole opening for the wheel studs were fairly large and there was no taper. I was like WTF? I had spoke with Jeggs before we placed the order and they assured me the wheel center required a taper style lug nut. Cool, that's what I have now. I also asked about the rears as my wheels have holes for 5/8" studs and use a flat washer and non tapered nut. He had no idea. I called Centerline and they said my current lug nuts will work. Now, today when I call asking about the fronts, which isn't a big issue. They say the fronts require shanked lug nuts. But then the guy tells me the rear do as well. Uh WTF? The rears won't be here for another week and a half and their specs are that the holes for the studs are just barely bigger than 5/8" which tells me the wheel will go over the 5/8 studs. The tech advisor told me I'd have to either install smaller studs in my axles or return the wheels and buy some of their competition wheels. Yeah, not happening. He did tell me that guys still run the flat washers and nuts like I have but he doesn't recommend it. So do any of you have any experience with this issue? The guy told me they quit machining the centers for the convo pros 10-15yrs ago for flat washers. I have 2 friends that got some maybe 4 years ago and they were. I'm betting it will work fine, I'm just nervous.

I ran a set of convo pros on a 71 el camino and they used shanked nuts. The holes were not tapered. That was in the mid eighties when they first came out. I don't know what they use now. I would go with what center line tells you. I ordered nuts, washers with them.

I can tell you with shank nuts you have to watch the depth of the shank. I bought them then had to cut some of the shank off as they hit the drum and did not hold the wheel tight. Just something else to check

Times 2 with what Charlie said. Gotta be careful the shank doesn't bottom out. I added longer studs (1/2") to take full advantage of all the threads and found that some of the shanks would extend beyond the depth of the wheel.

Also, after a cruise or two, verify the torque value. By then they stop needing to be "taken up" .

Convo's use the shank nuts. Washers and nuts are a "close, but no cigar" deal....over time it will put undue stress on your studs, and wallow out the holes in the rim.

Dave just to be clear. The shank nuts and washers came with the convo's . I ran them for around 20 years and never had a problem. Both drag racing and street. Do you know if they changed the nuts for them. Just curious.

Hank

Yes, the shank nuts with washers are the only right way to run them. I use the McGard shank nuts, very good fit and they come with the washers in the package!!!! I believe the OP is talking about any old washer with the right size hole and a regular wheel nut---not a good way to do it.

Thanks Dave, I agree.

Uh, no, I'm not referring to a regular old nut and a washer. They are the pieces that came with my Moser axles with drag studs. I just measured a shank type lug nut and they measure the same as studs in my axle. As long as there is a flat surface on the wheel for the washer and nut to seat, I don't for see an issue. But, a shank style lug nut isn't going to happen on a 5/8" stud. And the only thing the shank nut is doing over the studs I have are maybe center the wheel, but the studs are doing the same since they are the same size as the shank lug nuts. I guess I'll have to see how it goes because my Cragar 5 stars on the car are set up this way and they have seen many passes above 125mph with no issues.

The rear wheels showed up today and fit just like my old cragars. I could run them and not worry, but I came up with a way to help center the wheel since the shank lug nuts aren't being used. I have to run a spacer on my axle so the wheel will clear my brake caliper. I am going to have a new spacer made that snugly fits over my wheel studs. In the center I'm going to have a step so the wheel will be supported and centered just like a hub-centric wheel. This should eliminate any issue with the wheel not being centered. There is ample flat surface for my washers and nuts to seat on, so that won't be an issue.

New wheel


Old wheel

Should be a good lookin' combo! I wouldn't run any wheel that doesn't fit on the hub register! So your idea is definitely a good one imho...

The old wheels didn't either. I figured the new spacer will make it perfect and it will be no different than any hub centric designed application. Those lug nuts have a flat washer built into them to seat against the wheel to spread out the load.

You need to be aware of the fact that those wheels were designed and tested to meet certain specs and that was with the shank type nuts----Probably would be disqualifying at the track and also maybe even worse when used on highway---liability issues??????????

Please tell me how a shank type lug nut is going to change this situation here? The shank lug nut is centering the wheel on the wheel stud and takes up the gap from the wheel stud to the wheel hub area. A shank type lug nut also uses a flat washer under it's shoulder. Also, my wheel studs measure the same as a shank type lug nut. I've spoken with 3 different NHRA techs and they say the way I'm going to run it (Without a hub centric type spacer behind it) is how all the guys running these wheels is doing it with 5/8" studs and no one is having an issue with it. I also called Moser and asked them how others are doing it, and they told me the same thing. So, I can't see it being disqualified on a track, and that means we would have lost a wheel on the car by now street or track as this is how my previous wheels go on. I've never had an issue with the back wheels shaking or coming loose with the lug nuts being used here.

So are you saying I need to drop back down to teeny tiny wheel studs and run a shank lug nut so my wheel studs can shear when I do a whole shot jacking around?

No Ryan---I'm not telling you anything because it would be a waste of my time---I'm telling the other 30,000 members that there are SFI specs for wheels and fasteners-------------------