SLC Hubs/ race worthy

Howard Jones

Gold Supporter
#1
I know this has been discussed in the past, so in order to get this info all in one place and into the search function what would be the most current, 4/9/18, BEST and strongest hubs to use on a track use SLC. I need to replace all four corners ASAP.
First a few questions:

1. What year and model are the OEM direct replacement parts. Front and then rear.

2. I know the rears have a important factor that relates to the spline count of the stub axle. What is the required spline count and which model/ year corvette is this used on.

3. Please provide any source information that would be useful such as links to vendors.

4. Also add any good experience as to assembly/disassembly process, torque values, etc. and pictures you might have.

Thanks in advance, Howard
 
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Howard Jones

Gold Supporter
#3
Thanks Ed, I think that the fronts are the easer of the two questions to answer because of the same issue is present on the corvettes and other Chevys. However I need a suitable rear in addition to the fronts. I broke the left rear at COTA and the other side had a huge amount of slop in it also. +1/8". Very exciting moment.............when the car tank slapped at about a 100 with the brake peddle on the floor (pad knock back due to the left rear hub completely gutted and the tire/wheel/caliper +- 3/8 INCH of toe. All OK nobody hurt and no other damage.

THUS I am in need of best available race worthy rear hubs and the front to go with then as well.

I think you are correct the fronts appear to be C5-6 and I the rears C4. Thanks again for the info Ed.

Comments on these guys? Especially the spline count and SLC stub shaft compatibility. See various models in drop down year/model window .

SKF C5 C6 Corvette HD Racing Bearing & Hub
 
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Ken Roberts

Active Member
#4
The rears are from a C4 Corvette. The spline count is 27. The C5/C6 Corvettes use a 30 spline count and have a slightly different bolt pattern. They can't be used. Van Steel was selling a heavy duty version in the past for the C4 rear hub but I don't see it listed anymore on their web site. Give them a call perhaps.
The fronts are from a C4 Corvette. There is no heavy duty version available in a C4 Corvette size. You can use a C5/C6 wheel bearing in the front with a chromoly adapter. The adapters are very expensive. I am using them with SKF X Tracker C5/C6 hubs. These are the same hubs that were developed for the ZR1 by SKF. They now make them for C5 and C6 Corvettes as well. The ZR1 hubs have a 33 spline count and use a active sensor. SKF then came out with a 30 spline count hub with a passive sensor to accommodate track enthusiasts with early C5s and C6s up to early 2009. Hoosier Performance was selling a rebuildable heavy duty replacement setup for the front hubs but they closed their doors in January. Scott Swartz is using them.
 

Ken Roberts

Active Member
#5
The stock front and rear hubs supplied with the cars are (or were) made by WBI....Wheel Bearings Inc.

Personally I would only use SKF or Timken as a premium replacement for the stock hubs.

What I find confusing is the required torque value on the rear 27 spline stub axle nut in the hub. The C4 rear wheel hubs are basically the same from 1984 to 1996 but the torque spec change frequently on the stub shaft axle nut. I have factory service manuals available from various years C4 and the torque on the stub shaft axle nut changes a few times. Not sure which one to use!
 
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#7
Howard - very surprising to hear you had such a sudden failure, I know you’re super on top of inspections and maintenance. Was there any kind of event that may have caused such a sudden failure? How many track days do you have on the car, 6-10? Pretty limited street miles as well right?
 
#8
I have also suffered numerous bearing failures and very early replacement in both the front and rear. My car is mainly driven on the track at DE's and time trials. The c4 bearing are not up to regular track use...Period. I had to replace all 4 of the original bearings within 600 miles. I went back with three different brands (Timken, Skf, and National) and they all have failed or are in the process of failing. The National failed catastrophically where the hub flange sheared off the bearing barrel at high speed. The rotor jammed up into the brake caliper and that kept the wheel in place otherwise the wheel would have been launched at 100 mph. Not good. The rears fail faster. I now have been proactively replacing the rears after 1000 track miles. I think the SKF bearings seem to hold up better but I dont have good statistics to base that on.

Howard, I don't know what to tell you. Better bearings will help but if you stay with the c4 setup I would proactively replace them as my experience is they WILL fail eventually with track use. I talked to Fran about this and his suggestion was to upgrade to the race suspension which I think accepts the C5 hub. I plan to soon purchase the race suspension for the rear (about $4500) and stay with the c4 front setup and regularly replace the bearings.
 

Ken Roberts

Active Member
#9
The SKF X Tracker hubs will help solve the front hub problem. It's an expensive initial price but it can aid in keeping you and your car out of harms way. I just bought a whole complete second set for my next RCR car. The Chromoly adapters are about $470 for the pair and the X Tracker C6 hubs are about $720 for the pair.

The enthusiasts tracking their cars with them say you go from changing the hubs out from 2 to 3 times per season to once every two or three seasons. There is noticeable less pad knock back as well.
 
#10
Ken, so I found these guys. Same thing right. They sell the whole deal all together here:

Strano Performance Parts - Part Details

So that would solve the fronts. At least to a point, something like bearing change once a season.

So 5 track weekends @ 10 days @ 200 miles per day = 2000 miles a year. The X Trackers can be found for a bit over $350 each now or $1400 a year. Basically another set of tires, more or less in annual cost. That would be OK for me.

Now we need to figure out how to get them on the rear. I thinking we need a updated upright, stub-shaft (correct spline count), and the bearing per side. Right?

I have no interest in the speed transponders so for the record, what do the LS motor street car guys need for a correct speed sensor type.
 

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#15
Ken, so I found these guys. Same thing right. They sell the whole deal all together here:

Strano Performance Parts - Part Details

So that would solve the fronts. At least to a point, something like bearing change once a season.

So 5 track weekends @ 10 days @ 200 miles per day = 2000 miles a year. The X Trackers can be found for a bit over $350 each now or $1400 a year. Basically another set of tires, more or less in annual cost. That would be OK for me.

Now we need to figure out how to get them on the rear. I thinking we need a updated upright, stub-shaft (correct spline count), and the bearing per side. Right?

I have no interest in the speed transponders so for the record, what do the LS motor street car guys need for a correct speed sensor type.
I have no experience with these adapters from Strano. They are approximately the same price for the pair. He copied the design from the guy who sells/manufactures the ones I'm using. From the pictures I see an issue with his design on our uprights (see my post #592 in my build log). The Strano adapter has a more pronounced curve in this area and would require the SLC upright to have more material removed to compensate. Stick with the ones I talk about in post #591 of my build thread.

Ken's SLC build thread
 
#16
Strano Performance Parts may still have the Hoosier Performance rebuildable heavy duty hubs that Scott Swartz is using. They went out of business this past January but they may have a few left in stock at Strano.

The SKF X Tracker hubs are available in two models. They both have splined drives in them for use on the rear as well as the front. The C5/C6 model up to early 09 uses a 30 spline hub with a passive sensor. The later 09 and up C6 use a 33 spline drive and active sensor. The later C6 Corvettes switched to a Bosch style active ABS setup and better axles. If you don't care about using the built in speed sensors whether passive or active then your cheapest option might be to buy a OEM GM part number ZR1 front or rear hub. They are the SKF X tracker hub that started it all. I believe I saw them being sold on Rock Auto for much less than the $370 version we are discussing.

If I had to choose I would go with the model with the passive sensor in case you upgrade to some kind of traction control in the future. That is unless you are going to run some kind of aftermarket standalone ABS system like the Bosch which uses a active sensor or some type of engine control system that uses a active sensor for built in traction control like Motec.

If none of this is a concern than order any one of the two. Just cut the wires off the hubs.
 
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#17
Ok thanks for that Ken. Ya...it would be way too lucky to find a off the shelf stub shaft from a unrelated SLC source but at least this would be a lead to someone who could make them. Also the prices are interesting. In any case your info is just what I was intending with this thread. Find a fix for the whole car and put in a thread that would be helpful to all of us. Good stuff, thanks buddy.

Cam, I'm not that surprised really. I am running huge slicks on a track only car with significant power and torque and beginning to pick up the pace. So "cost centric" C4 street car pieces should be replaced with race intended parts anyway in such a environment. These kind of loads cannot be achieved on the street....they just can't. The rears on my car did last 558 miles, all of which was on slicks and at the track. Pretty much in keeping with other's track use experience. On the other hand I haven't heard of street only cars having this issue. At least as far as the information I know of. I wouldn't do anything for now if I was you and I wouldn't get too concerned considering the stage of your build. You have plenty of time before you need to consider this issue.

I will come up with a solution one way or another. Watch this space.
 
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#20
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