Sprocket hubs failure
- Thread starter ROBY427
- Start date
Jim Craik
Lifetime Supporter
Jack,
As of yet, no problems with bearings, every time I change the oil, or replaced the tires, I always give all the wheels a good check for any "play", as of yet, they have not shown any and the bearings seem to spin just fine, (that sound you hear is me knocking on wood
).Keep in mind, I have not "tracked" it, but 80% of my driving is on mountain roads and on a clear road I may get to 8/10ths....
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Dave Hood
Lifetime Supporter
I’ve got an update to this thread which I hope will be useful for Superformance owners. About a month ago I noticed excessive play in my front wheels, as well as a noise which raised concern. I brought my car to Holman Moody which is close to my house, and Lee Holman and his crew determined that there was too much free play in the hubs, and that the bearing seats and dust covers were destroyed. As a result, the bearings heated up and wore down the spindle to the point where new bearings would have had the same problem within a short period of time (see photo). The dust shields were also destroyed by the failed bearings. Holman Moody concluded there were at least two major problems with the Superformance design. First, the quality of the metal they use for the hubs is likely substandard. Second, without installing spacers between the outer and inner bearings, too much free play exists and the bearings don’t seat properly. A third problem may be that Superformance didn’t machine their hubs with the proper tolerances for the bearings.
Since installing new bearings on the worn hubs wasn’t a viable solution, the only two options were to replace the hubs or take the damaged hubs and have them built up with chrome plating and then ground down to the proper tolerance before installing new bearings. Since Superformance charges $1,600 for each new hub, I elected to take the second approach. One hub worked fine, but the other warped during the plating process because the Superformance spindle was made so cheaply. Fortunately, Lee Holman happened to have a spare Superformance hub in his shop. Holman Moody also had a stainless steel spacer/crush sleeve built for each hub (see photo), and installed those to ensure the new bearings would seat properly on the hub. If any Superformance owners would like to install these, I recommend that you contact Lee Holman directly.
The big take away for me is that Superformance could have done a much better job designing their hubs. Had they used better materials and installed spacers as part of their original design, their product would have been far superior. My car only has 8,500 miles and has been meticulously maintained by Dennis Olthoff and Lee Holman. Superformance’s response may be that they wanted to build a product close to the original race cars. But since most of these cars are being driven on the road, and owners might not change their bearings every few thousand miles, designing a more durable hub assembly and using better materials would have been helpful and probably not that difficult. If you’re a Superformance owner, this is absolutely something to watch carefully.
Since installing new bearings on the worn hubs wasn’t a viable solution, the only two options were to replace the hubs or take the damaged hubs and have them built up with chrome plating and then ground down to the proper tolerance before installing new bearings. Since Superformance charges $1,600 for each new hub, I elected to take the second approach. One hub worked fine, but the other warped during the plating process because the Superformance spindle was made so cheaply. Fortunately, Lee Holman happened to have a spare Superformance hub in his shop. Holman Moody also had a stainless steel spacer/crush sleeve built for each hub (see photo), and installed those to ensure the new bearings would seat properly on the hub. If any Superformance owners would like to install these, I recommend that you contact Lee Holman directly.
The big take away for me is that Superformance could have done a much better job designing their hubs. Had they used better materials and installed spacers as part of their original design, their product would have been far superior. My car only has 8,500 miles and has been meticulously maintained by Dennis Olthoff and Lee Holman. Superformance’s response may be that they wanted to build a product close to the original race cars. But since most of these cars are being driven on the road, and owners might not change their bearings every few thousand miles, designing a more durable hub assembly and using better materials would have been helpful and probably not that difficult. If you’re a Superformance owner, this is absolutely something to watch carefully.
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Jack Houpe
GT40s Supporter
Good info Dave, these bearing failures are hit and miss, I check mine frequently and haven't found any slop in them yet (13k miles) but know 2 other guys who have 1 with less miles, and 1 with over 35k. Whats the percentage of cars Dennis has seen with issues? If its high perhaps someone should stock sell new upgraded hubs with sleeves for swap outs with cores.
Dave Hood
Lifetime Supporter
Jack, my impression from Dennis is that he sees a lot of these issues. He told me last year that he had a solution in mind, but that it would cost him a lot of money to get his idea into production. I don't know what the solution was he was considering, however. Lee Holman seemed to think that the spacers would be a huge help. However, if the root of the problem is poor quality metal being used by Superformance, or poor tolerances in their machining process for the hubs, that's a bigger issue.
Howard Jones
Supporter
Could this be used. It looks like it is made for seals but I wonder if it would work for bearing fit improvement.
SKF Speedi-Sleeve
SKF Speedi-Sleeve
Hi Dave,
I’ve just read your post about the bearings/hubs failures on our SPF GT40 and I’m very sorry to forget to upgrade the post once I solved my problems months ago.
Well I absolutely agree what you wrote about hub quality: I bring mine to a retired Airbus chief engineer that examined the hubs and told me that for a car with 10000 miles the hubs should be new and bearings too. He told me too that the quality of hub materiel is poor and suggested me 3 things to repair:
1. Replace the hubs => too expensive solution (1500$/each)
2. Chrome plating => I asked in France for a quote it was 850$ for the 2 rear hubs.
3. Add a sleeve on the hubs => that’s the solution I took and here is why:
When my friend from Airbus talk to me about chrome plating he told me that I should get the same problems in the future due to small size of inner/outer bearings as I use the car 90% on the roads (with bumps/poor quality roads).
He told me that adding a sleeve on each hub would be a definitive solution to my problem and with that solution I could add bigger bearings (diameter/width) that could very improve their life.
First of all I’ve check on Timken’s web site to find bigger bearings. Next I went to my machine shop asking him to build sleeves to fit new bearings and machine the 2 uprights for new bearings.
So now here is what I have on my rear hubs:
- Old Inner bearings : 18690 – New Inner bearings: 18720
- Old Outer bearings: 18720 – New Outer bearings: 32010x
Here are the pictures of the sleeves installed on the hubs, the difference between 18690 and 32010 bearings and the old/new Nilos.
OlivieR
I’ve just read your post about the bearings/hubs failures on our SPF GT40 and I’m very sorry to forget to upgrade the post once I solved my problems months ago.
Well I absolutely agree what you wrote about hub quality: I bring mine to a retired Airbus chief engineer that examined the hubs and told me that for a car with 10000 miles the hubs should be new and bearings too. He told me too that the quality of hub materiel is poor and suggested me 3 things to repair:
1. Replace the hubs => too expensive solution (1500$/each)
2. Chrome plating => I asked in France for a quote it was 850$ for the 2 rear hubs.
3. Add a sleeve on the hubs => that’s the solution I took and here is why:
When my friend from Airbus talk to me about chrome plating he told me that I should get the same problems in the future due to small size of inner/outer bearings as I use the car 90% on the roads (with bumps/poor quality roads).
He told me that adding a sleeve on each hub would be a definitive solution to my problem and with that solution I could add bigger bearings (diameter/width) that could very improve their life.
First of all I’ve check on Timken’s web site to find bigger bearings. Next I went to my machine shop asking him to build sleeves to fit new bearings and machine the 2 uprights for new bearings.
So now here is what I have on my rear hubs:
- Old Inner bearings : 18690 – New Inner bearings: 18720
- Old Outer bearings: 18720 – New Outer bearings: 32010x
Here are the pictures of the sleeves installed on the hubs, the difference between 18690 and 32010 bearings and the old/new Nilos.
OlivieR
I just need to chime in here for a moment. If the material used to make the spindle is only one step up from chocolate is the the thread that holds the wheel on via the spinners not also a bit suspect?
Bob
Bob
I have to differ with the conclusion that metal quality is the problem. My experience is that machining tolerance is not tight enough on some new hubs allowing the bearings to wobble. The lack of a bearing spacer adds to the wobble. The design relies on the adjusting nut with very fine threads holding the bearings tight which is more than they can cope with. Eventually the nilos seals get cut and grind up metal filings into the whole assembly. Without metallurgical testing we may be speculating on the metal quality of the hubs. Concerning the spinner threads my spinners are always very tight and require a lot of effort to loosen. Haven't heard any SPF owners complain about spinner threads.
Oliver your solution seems a good one even without a bearing spacer. What was the cost for sleeves and upright machining? Thanks for detailing your solution.
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Fitting sleeves are common on any shaft that needs reclaiming so should be pretty much an off the shelf item from any bearing shop. You could also add a crush tube between the races , that would also add support without over tightening the bearings.
Bob
http://www.gt40s.com/forum/attachment.php?attachmentid=73104&stc=1&d=1405442631
Bob
http://www.gt40s.com/forum/attachment.php?attachmentid=73104&stc=1&d=1405442631
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Dave here are the price details about my solution:
- Machine the 2 rear uprights + 2 sleeves ==> 300€ so 400$
- New bearings (2x 18720 + 2x 32010 + cones + nilos) ==> 185€ so 250$
I suppose prices will be cheaper in the US....
I'm meeting the same problems on the front so I'm going to do the same job.
By the way after driving the car for 2000 miles since the job done on rear bearings/uprights nothing has moved and absolutly no plays on rear wheels.
OlivieR
- Machine the 2 rear uprights + 2 sleeves ==> 300€ so 400$
- New bearings (2x 18720 + 2x 32010 + cones + nilos) ==> 185€ so 250$
I suppose prices will be cheaper in the US....
I'm meeting the same problems on the front so I'm going to do the same job.
By the way after driving the car for 2000 miles since the job done on rear bearings/uprights nothing has moved and absolutly no plays on rear wheels.
OlivieR
Dave Hood
Lifetime Supporter
Dave, without testing the hubs I agree we can't make a firm conclusion that the metal is suspect. But I think we all agree that the machining tolerances on many of the hubs Superformance produces is an issue. Sleeves with a crush tube between the inner and outer bearings seem like the ultimate solution to me. And I really like the idea of using larger bearings that will wear better during typical road driving.
Dave Hood
Dave Hood
Have any of you contacted SPF or Lance Stander regarding this concern as it appears to be pretty common and I'd be interested in hearing their response? Don't have a SPF GT40 but been considering getting another GT40 and SPF is one I'm interested in.
Mike
Lifetime Supporter
Having recently serviced mine at ~4k miles I notice a slight indication that the races might have rotated on the hubs. They were never lose but one of the dust seals up front had been chewed up. There was no indication that there was any damage to bearing surfaces or gulling to hub. I cleaned and repacked bearings and reinstalled. I don't run any preload on the bearings. I have been checking them over the last 500 miles or so and there is no indication of any looseness or damage to the dust shields. Dennis mention the dust shields tend to self destruct after awhile so I'll probably plan on replacing and surfacing the gun assemblies in another couple years after another 4k miles.
Dave Hood
Lifetime Supporter
Holman Moody's engineer Jim Rose was a crewmember at Alan Mann Racing in the mid 60's. So he's worked on these cars since they were first developed. The SPF dust shields are true to the original version, and were meant to be changed at the end of each race. I think this is one area where SPF could have injected more practicality into its design, knowing that most of their cars would be run on the road.
If there are issues with the shaft diameter , the bearings and the inner seals why not machine the spindles down to 50mm and install metric bearings instead of the imperial size. That gives you .8 of a mm to remove which would negate the need for the sleeves. While your at it change it over to two double row ball races with seals already installed, four ball races in effect per hub. That will be a lot stronger , less trouble and cheaper. Just thoughts.
Bob
Bob
Mike
Lifetime Supporter
Is this a case where there is a design improvement that could be made but there simply is not enough demand to warrant the costs of coming up with a solution? I have a great fabrication guy but not sure how many if any would be interested in a solution that could end up costing several thousand dollars? It's frankly not a difficult job to pull the hubs and service the bearings and dust shields once a year or every other. I think of it as quality time in the garage that allows for close inspection of several components on the car.
Dave Hood
Lifetime Supporter
I sent Lance at Superformance a link to this thread, and I've asked him to let me know what he sees as the solution for those that own GT40s he's imported into the US. I'm sure he knows these issues exist. I don't know if I've ever seen him post on this forum or distribute any technical information to owners in the US. That's not good, but it is what it is. I'll see if he responds. If he doesn't, I'll call their office in Irvine.
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