SLC Hubs/ race worthy

As I mentioned previously I am having new rear uprights made to accept the 33 spline hub bearings that fit the 2009+ ZR1/C6 2010+/C7 (all). This bearing is essentially the same as the XTracker. The upright will be dimensionally the same as the RCR version other than the hub mounting flange is 2mm out board of the current location. The c7 hub is slightly shorter than the c4 hub (see photo) by about 5mm and therefor moves the wheel mounting flange inboard by the same so I moved the flange outboard 2mm. The wheel flange on the C7 setup will still be 3mm (.12") inboard of where it is now with the c4 hub setup.

I got C7 33 spline axle stub from The Driveshaft Shop in Salisbury, NC part #108-GM-O-33 for $316 each plus shipping. Website says they are good for 900whp. It bolts right up to our 930 6 bolt CV. This spline shaft is shorter by .75" and is too short with our axles so you have to add a 1/2" spacer which they supply. I dont have a price on it because I plan to make my own. Alternatively you can order slightly longer axles from them for a couple of hundred bucks each. I got my C7 hub bearing for $95 + shipping from one of the online gm parts sites. Part #23193306.

I hope to have the first trial upright in hand in a few days. If all goes well I will have him make some extras. I know Ken wants a set, how about anyone else? They will cost between $400-450 plus shipping.

I am enclosing photos of the new c7 bearing next to the c4 and the same for the hubs. Also there is a shot of my failed c4 spline shaft and the other one that if you look closely you can see is twisted and about to fail. I have had several c4 Vettes and this is common if you had sticky tires our more HP.
 

Attachments

Howard Jones

Supporter
C4 on left and C7 on right

Paul, funny how we are thinking alike, I sent them a email asking if they can custom make that same stub shaft to length and they cannot.

John B, can you supply the above correct length stub shaft? I can supply a sample C4. This would allow us to use the original drive shafts, so you would be able to include that cost in consideration as to price.
 
Last edited:

Brian Kissel

Staff member
Moderator
Lifetime Supporter
Just got a call from Dan at Vette Works. The hubs listed on their site are no longer available. He said he called Van Steel to verify and they are no longer available. I also will be looking for an alternative . I am planning building a RCR Lola T70, and will probably need to build new uprights also to handle the C7 bearing. I am watching this with great interest. THANKS everyone for the great information.

Regards Brian
 

HCF - John

Gearbox / Brake Systems
Yes, we're able to make custom stub axles.

A true one-off is expensive. It makes the most sense to design a stub axle that works with a common bearing and a universally-adopted upright replacement.


C4 on left and C7 on right

Paul, funny how we are thinking alike, I sent them a email asking if they can custom make that same stub shaft to length and they cannot.

John B, can you supply the above correct length stub shaft? I can supply a sample C4. This would allow us to use the original drive shafts, so you would be able to include that cost in consideration as to price.
 

Howard Jones

Supporter
John, what I think we need is the C7 33 spline stub shaft redone exactly as it is with the exception that it would be the same overall length as the C4. As you can see in post #143.

The area between the spline root and the CV face, I'll call it the "bell segment", should be contoured like the C4. This is to clear the back of the upright in the same way as the original.

Maybe we could see how it all goes together for Paul and then go from there. It might be that the C7 stub shaft will work with spacers to correct for the length as it relates to the CV joint/driveshaft length.

I could supply the C4 stub shaft, and a bearing with the correct splines if need be. Let me know what you think.

Oh, and I contacted the Driveshaft Shop and the 1/2" spacers are $53.00 each.
 
Last edited:

HCF - John

Gearbox / Brake Systems
Hi Howard - sure, if we can make sure Paul's will work with the same axle, that would be no problem.


John, what I think we need is the C7 33 spline stub shaft redone exactly as it is with the exception that it would be the same overall length as the C4. As you can see in post #143.

The area between the spline root and the CV face, I'll call it the "bell segment", should be contoured like the C4. This is to clear the back of the upright in the same way as the original.

Maybe we could see how it all goes together for Paul and then go from there. It might be that the C7 stub shaft will work with spacers to correct for the length as it relates to the CV joint/driveshaft length.

I could supply the C4 stub shaft, and a bearing with the correct splines if need be. Let me know what you think.

Oh, and I contacted the Driveshaft Shop and the 1/2" spacers are $53.00 each.
 
We got our redesigned rear upright back and it fits!! We are now having the right side made. As I mentioned earlier the C7 hub/spindle assembly is sorter than the existing kit by about 0.78" so you have to either put a spacer between the spindle and the CV assembly or get slightly longer axles. I think I am going to get longer axles. The spacers are like $53 each side and the axles are $225. So all in with new axles, this conversion costs $1110 per side plus shipping and taxes (upright $475, spindle $316, hub $96, Axle $225). It would be $938 if you go with a spacer. I think I am at a point where I can take orders for the new uprights if anyone is interested in doing this. I may do a separate post on this subject soon.
 

Attachments

Howard Jones

Supporter
Paul.

1. Do you have clearance from the stub shaft bell on the inboard side of the upright for the head of the cap screw? If not the inboard face will need the three mounting holes countersunk.

2. Does the above upright come drilled and taped for the toe link and ball joint plate.

3. Does the rotor mounting face line up in the same place or will we need to shim the rotor/wheel outboard?

4. If I order two uprights can I get the un-sculped version (big hunk of aluminum) with all drilling/threading/countersinking complete ?

Thanks for all this work. Really well done.
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
Paul, while I am amazed at your enginuty - at this point I need to ask you to stop any attempts at sales on this forum until you have taken steps to reach out to Ron Earp and become a registered vendor here...

Thank you...
 
So from the Driveshaft Shop...... the new axle shaft and 33 spline stubshaft would cost about $550. Add shipping in your axles and shipping back about $75. We are at about $625. Can John B make us new 33spline stubshafts for this amount instead? (or somewhere in this region)
 

Howard Jones

Supporter
Ken, I think the issue on stub shafts may well be volume. I have talked to a couple of other spline shaft/axle custom part suppliers and it's pretty hard to get just a handful in a reasonable short time and at a price that will not be prohibitive. They'll do it, but not for $316 each. Even if you add in the driveshaft cost I think we are still in the black on a small order of 10 or less.

Then there is the design and setup cost. No one will do it without, at the least, a sample(s) to produce a drawing and a first article. Then there will be shipping to and from the maker. This all gets complicated for such as small number of units. On top of that there is typically a minimum order of at least 10 and as much as 30 in one case. So it just might be less expensive to replace the driveshafts, or use spacers, and use the existing DSS stub shaft.

The stub shaft from the Driveshaft shop is also a "in stock" piece and it is reasonable to expect that it will remain available over time. This is the key part to adapt the car to C7 bearings and solve the track car reliability issue without a complete re design of the suspension and it's prohibitive cost.

The up right isn't necessary IF and I emphasize "IF" you have the MK1 version like mine and a good drill press. It can be re-drilled to take the C7 bearing. However the newer and nicer MK2-3? uprights make a simple re-drill pretty difficult if not possible at all. So if we are trying to solve the issue for all cases in the small population of SLC track use cars we need a common upright that will accommodate the C7 bearing, and if possible not require a change in rotor/caliper orientation.

The front of the car has the same C7 requirement in my opinion but we have a proven solution. A better one would be a up right drilled for the C7 bearing and designed to place it in the proper offset. This is a more detailed design exercise and requires at a minimum a fairly expensive manual mill or custom upright much like the one Paul has had made. It would not however not be a re-drilled OEM Upright like the back as it would need to address the C4 bearing overall offset difference from the C7 type.

In both cases it would be very beneficial to be able to replace only the body of the upright and re use all the other pieces.

Randy.

I started this thread to see if the group could solve this problem for ourselves and at the same time illustrate just how involved a relative simple thing like this can become. Paul and I have been talking about this for quire a while now and I think that there is very little money to be made given the limited number of potential users/customers. I don't think Paul is trying to get rich off this, just fix his car and help others as am I, but then I'll let him speak for himself if he so wishes. I for one COMPLETELY agree to abide by the rules of this forum.

So far there have been several possible sources identified that might have been a partial solution that for one reason or another did not work out. If someone HAD a piece to "vend" we all could just buy, then it would have been identified and linked and this all would be moot.

How about we let this process continue until we see a better refined picture of the solution. As of now it is a bit incomplete and there is only one proof of concept upright in existence. As far as the costs go, the prices stated throughout this thread have only been the pass through costs as far as I know to inform interested others.

It would be a shame if the last piece was left to the imagination or simply shifted to private.

Thanks for you interest, your work as a moderator, and justified concern (just a bit early IMHO) .
 
Last edited:
The C7 Corvette 33 spline stubshaft uses a axle nut that takes a 36mm socket. The part number for a replacement axle nut is #11611234. The torque value for installing is 184 ft/lbs.

Paul mentioned that the nut was included in the hub purchase from a GM dealership. Mine are on order and I'll further update this post if the nuts were included in the boxs as well.

Paul did mention that the three bolt holes will be countersunk for clearance of the bell section of the stubshaft. They will all be machined like that in his first revision 1.1 with the machinist. The pictures he posted was the first test upright.
 
Last edited:

Howard Jones

Supporter
Ken, thanks for that I was wondering where/what to get. Great catch on the countersunk holes. I am getting pretty close to pulling the trigger on the bearings and stubshafts myself.

I am going to see how things work with my uprights as a guinea pig test trial fit 1st go around deal and then talk to Paul again.
 
Last edited:

HCF - John

Gearbox / Brake Systems
Ken - I'm not sure what it will cost to make custom stub axles. As I've mentioned before, I need a sample in order to quote anything. Do you have one you're willing to be without for a few weeks?



Howard - if it's acceptable for owners to use spacers you are absolutely correct that the Driveshaft shop solution will be the most cost effective. They likely make them in large quantities, they are off-the-shelf and don't require a special run.



We don't need to do a large run of them to be willing to make them. Technically it may be possible to make an adapter for the rear, similar to those you are using for the front. It's probably not much more expensive to just replace the upright, though.... both things that can be evaluated with sample parts.
Best,
John
 
Paul, while I am amazed at your enginuty - at this point I need to ask you to stop any attempts at sales on this forum until you have taken steps to reach out to Ron Earp and become a registered vendor here...

Thank you...
Wow, so let me start off with a mea culpa! I had and have no intention of running afoul of the forum. I guess I am very uninformed when it comes to forum policies etc. That being said I certainly don't consider myself a vendor. I am not sure how you define vendor but I would image that most vendors would envision making some sort of profit off whatever they are offering and that would definitely not be my case. I would need to charge about $1500 a piece to compensate me for my time. The price I am passing along is what my machinist is charging me. And I don't think he is profiting from this exercise either as he is doing this as more of a favor for me for past business.
This is more of a collective effort. I think Howard was spot on in his characterization of our effort on this.

So that being said if the powers that be require me to become a vendor to offer this part to the SLC community then no thanks and I will withdraw my offer to have this part made.:thumbsup:
 

Randy V

Moderator-Admin
Staff member
Admin
Lifetime Supporter
Paul - this is not my site (GT40s.com) which is why I encouraged you to reach out to the site owner (Ron Earp). He may well give you a pass. I am not going to make a judgement call on what constitutes profit. I merely saw you offering made to order components with specific pricing. We have other people here that perform similar services that are paid vendors. What would you have me or Ron tell them?
While the effort certainly appears to be a noble one on your part, it does trip the “I’m a vendor” flag...
Please do PM Ron Earp and check in with him.
Thank you..
 
Top