uprated cv joints

[astontr6]

On 11/6/2023 at 6:40 AM, Waldi said:

Our German friends on the TR-Freunde forum are not exactly positive although that was a couple of years ago. This is why I bought a set from CDD.
I’m looking forward to the outcome of the inspection of Ian’s GT6 failure.

Waldi

I fitted Limora over 5 years ago and have had no trouble. At the time I did not go for the CDD ones as there  were a number of reports of them failing with very low mileages on this Forum.

Bruce.

[Mk2 Chopper]

12 minutes ago, astontr6 said:

I fitted Limora over 5 years ago and have had no trouble. At the time I did not go for the CDD ones as there  were a number of reports of them failing with very low mileages on this Forum.

Bruce.

Wow so the very thing that we're being scare mongered into thinking with the original hubs, is not necessarily any better with some after market ones! 

It's a shame we can't get some definitive data on who's had a failure and whether they were original or aftermarket. I don't frequent the American forums, but you'd think if anywhere they'd have more knowledge about this failure seeing as they had so many more cars out there. 

Gareth

[Motorsport Mickey]

Sorry you think it’s scaremongering Gareth, the results of these original hubs breaking are there to be seen and have been reported on the forum before. I was aware by bringing it to owners attention that it may prove “ contentious” but I’m satisfied I did it for the correct reason and as a service to owners. 
You are correct to say that not all of the replacement hub makers have suffered breakages. There are at least 2 makes who specialise in large output engines and/or Competition cars where stresses are high, and these have not had failures recorded on the forum by their owners. Perhaps this should be born in mind when replacing old hubs.

As far as I’m aware the previous new hubs with failures, HAVEN’T suffered with broken stub axles or broken hubs. As we’ve reported we are awaiting different reports from owners on a GT6 and on Stag, to see what caused their particular failures. I hope that information will help.

Mick Richards

Edited November 10, 2023 by Motorsport Mickey

[astontr6]

1 hour ago, Mk2 Chopper said:

Wow so the very thing that we're being scare mongered into thinking with the original hubs, is not necessarily any better with some after market ones! 

It's a shame we can't get some definitive data on who's had a failure and whether they were original or aftermarket. I don't frequent the American forums, but you'd think if anywhere they'd have more knowledge about this failure seeing as they had so many more cars out there. 

Gareth

I do have a criticism of the Lamora type is that the male spline did not enter the female spline fully and one had to do a fitting job? It was easy for me as I had served a proper English Apprenticeship as a Tool Maker. This problem has never been talked about by others on our Forum.

Bruce.

[stuart]

We did have a problem with a set of CDD shafts and it was posted about several years ago, the hubs were to thick which meant the brake drums would sit sufficiently home, denied at the time as being a problem, sorted locally by machining the hub but didnt inspire confidence.

Stuart.

[Mk2 Chopper]

1 hour ago, Motorsport Mickey said:

Sorry you think it’s scaremongering Gareth, the results of these original hubs breaking are there to be seen and have been reported on the forum before. I was aware by bringing it to owners attention that it may prove “ contentious” but I’m satisfied I did it for the correct reason and as a service to owners. 
You are correct to say that not all of the replacement hub makers have suffered breakages. There are at least 2 makes who specialise in large output engines and/or Competition cars where stresses are high, and these have not had failures recorded on the forum by their owners. Perhaps this should be born in mind when replacing old hubs.

As far as I’m aware the previous new hubs with failures, HAVEN’T suffered with broken stub axles or broken hubs. As we’ve reported we are awaiting different reports from owners on a GT6 and on Stag, to see what caused their particular failures. I hope that information will help.

Mick Richards

I've tried searching for this Mick, using Google not the search on here, and all I get is a list of questions asking if a hub is about to fail, and people complaining about CDD versions having lots of play. I'm just not seeing the evidence, but rather reported hearsay about it. I'm not saying it isn't true, but I can't easily seem to find that evidence? 

And certainly it's no good to be putting information out there about the imminent danger of using original Triumph hubs, when it's possible that an alternative aftermarket solution may be no better (or possibly worse). We've yet to be assured of that particular brand. 

I agree that the versions that are used in competition or cars with uprated power engines are worth a look. 

Gareth

 

[stuart]

1 minute ago, Mk2 Chopper said:

I've tried searching for this Mick, using Google not the search on here, and all I get is a list of questions asking if a hub is about to fail, and people complaining about CDD versions having lots of play. I'm just not seeing the evidence, but rather reported hearsay about it. I'm not saying it isn't true, but I can't easily seem to find that evidence? 

And certainly it's no good to be putting information out there about the imminent danger of using original Triumph hubs, when it's possible that an alternative aftermarket solution may be no better (or possibly worse). We've yet to be assured of that particular brand. 

I agree that the versions that are used in competition or cars with uprated power engines are worth a look. 

Gareth

 

Weve been using new Bastuck hubs for a number of years with no problems. Not such an expensive solution.

Stuart.

[iani]

2 hours ago, Motorsport Mickey said:

<snip>

As far as I’m aware the previous new hubs with failures, HAVEN’T suffered with broken stub axles or broken hubs. As we’ve reported we are awaiting different reports from owners on a GT6 and on Stag, to see what caused their particular failures. I hope that information will help. </snip>

 

 

I collected my broken shaft from Wards this afternoon, they were able to pull the hub off ok, nothing had seized & the bearing still contains the original blue grease and turns freely. The shaft has sheared towards the inboard end of the woodruff key slot, the shaft is still bright and shows no sign of blueing which you would expect if it had been subject to high temperatures. I will take some pics of it this weekend and send to CDD for comment.

Edited November 10, 2023 by iani

[Motorsport Mickey]

21 minutes ago, iani said:

I collected my broken shaft from Wards this afternoon, they were able to pull the hub off ok, nothing had seized & the bearing still contains the original blue grease and turns freely. The shaft has sheared towards the inboard end of the woodruff key slot, the shaft is still bright and shows no sign of blueing which you would expect if it had been subject to high temperatures. I will take some pics of it this weekend and send to CDD for comment.

Thanks Iani, we await with interest.

Mick Richards

[Mk2 Chopper]

1 hour ago, stuart said:

Weve been using new Bastuck hubs for a number of years with no problems. Not such an expensive solution.

Stuart.

From their website you can buy the inner axle shaft, I'm guessing you could have a set of hubs refurbished and add these to get around potential damage from pressing apart the hubs? 

Does anyone sell them over here in the UK?

Gareth

[Motorsport Mickey]

1 hour ago, Mk2 Chopper said:

I've tried searching for this Mick, using Google not the search on here, and all I get is a list of questions asking if a hub is about to fail, and people complaining about CDD versions having lots of play. I'm just not seeing the evidence, but rather reported hearsay about it. I'm not saying it isn't true, but I can't easily seem to find that evidence? 

And certainly it's no good to be putting information out there about the imminent danger of using original Triumph hubs, when it's possible that an alternative aftermarket solution may be no better (or possibly worse). We've yet to be assured of that particular brand. 

I agree that the versions that are used in competition or cars with uprated power engines are worth a look. 

Gareth

 

 

Gareth,

You may have more luck searching in the Forum for Hubs or Driveshafts, it's longhand but if you manually search the threads you'll come up with confirming threads that I've been quoting here.

As I said before ..."Please don't take my comments above as an advertisement or endorsement for CDD or any other manufacturer or process of keeping the wheels upon any Triumph. Sometimes in life and after researching with due diligence you make a choice which you have to stand by, which I have done with mine."

However disappointing that a number of the replacement hubs (themselves Triumph copies) have had problems, and also the more modern designs replacing them have not been trouble free, I await with interest the results of the supplying dealer and manufacturer to the customer going forward. 

Mick Richards

[Waldi]

Thanks for the update Ian.

Cheers,
Waldi

[Mk2 Chopper]

23 minutes ago, Motorsport Mickey said:

 

Gareth,

You may have more luck searching in the Forum for Hubs or Driveshafts, it's longhand but if you manually search the threads you'll come up with confirming threads that I've been quoting here...

Mick Richards

Thanks Mick,

I did find a thread which linked to another that someone had a sheared axle. They are certainly not that easy to find though. 

I feel there are a few good options out there for replacement, either uprated or standard set up. If anything my search has highlighted problems (not safely related) with a certain upgrade CV version that we are awaiting more information on. 

Gareth

 

 

[Casar66]

Quote

Weve been using new Bastuck hubs for a number of years with no problems. Not such an expensive solution.

Had them. Can not recommend them. One last for only a few hundred miles. And on top the "anti-customer-service" from the Bastuck people. Never ever.

 

[Andy Moltu]

Chris Hale had one of the new reproduction hubs fail as he pulled into the campsite at Malvern last year. The new hub bearing hadn’t been set up properly and the hub nut undid itself and the hub fell apart and the wheel came off.

 

[harrytr5]

Iani,

Any info on what the manufacturer conclusion was ?

Regards Harry

[RogerH]

On 11/10/2023 at 5:27 PM, Mk2 Chopper said:

From their website you can buy the inner axle shaft, I'm guessing you could have a set of hubs refurbished and add these to get around potential damage from pressing apart the hubs? 

Does anyone sell them over here in the UK?

Gareth

Hi Gareth, 

I hope I haven't got my wires crossed but Moss sell a complete NEW hub to the TRiumph design.

They also sell all the parts including the  drive shaft with UJ yoke.  These are made in the UK (in Surrey)

 

I have a pair that I fitted in 2017 and they are doing very well.

 

Roger

[Mk2 Chopper]

3 hours ago, RogerH said:

Hi Gareth, 

I hope I haven't got my wires crossed but Moss sell a complete NEW hub to the TRiumph design.

They also sell all the parts including the  drive shaft with UJ yoke.  These are made in the UK (in Surrey)

 

I have a pair that I fitted in 2017 and they are doing very well.

 

Roger

Thanks Roger, 

No not at all, I welcome information about what is available. 

Gareth

[deryckp]

Further to the discussions about the CDD driveshafts I thought you may be interested in the attached comments.

I have had a pair of CDD CV jointed drive shafts on my TR6 for several years and around 16000 miles with no problems. When my friend Ted Roberts was looking to upgrade the drive shafts on his Stag, in which he competes in sprints and hillclimbs I was happy to recommend CDD to him. When I read the previous post in which his car was mentioned I asked him if he wished to comment. His words are posted below. I would mention that the primary reason behind both our choices was to get the improved hub design, and the CV joints were an added bonus.

"Possible cause of failures on two uprated constant velocity driveshafts manufactured by Classic Car Developments fitted to Triumph Stag.

Following advice from a Triumph Register member who explained the design issues with TR6 driveshafts that can fail due to metal fatigue causing the wheel that is secured to the driveshaft to become detached from the car. The serious consequences of this were later brought home to me after speaking to a fellow Hillclimb competitor who had spent 6 weeks in hospital after a standard drive shaft on his TR6 failed when competing in a sprint. This convinced me I should invest in a pair of driveshafts that had the wheel bearing hub bolted to the suspension arm and constant velocity (CV) joints to smooth out uneven rotation of the standard universal joints. The shafts manufactured by Classic Car Developments (CCD) were purchased from E J Wards in August 2020 and fitted to my Triumph Stag 1974 MK2.

On inspection, the driveshafts appeared very well made and I was surprised when both shafts failed after only 8,288 miles. I have used the Stag on 3 Sprints, 6 Hillclimbs, about 50 competitive miles, and 5 non-competitive Driving Assemblies with the remaining mileage visiting shows and general use. The first to fail was the left-hand (LH) shaft when exiting a 20 mph left-hand uphill corner followed a week later by the right-hand (RH) shaft that failed in a similar manner when accelerating from a 20 mph right-hand corner. So I was pleased that the wheels remained firmly fixed on the Stag and I was able to pull over safely without damage to me or the car. With the Stag out of commission, I decided to order 2 new replacement CCD driveshafts from E J Wards to avoid missing the rest of the season.

 

The following pictures show the failure of LH and RH driveshafts.

 

 

 

 

 

 

 

 

 

The suggested failure mode on both LH and RH driveshafts are at the same place where the splined outboard end of the driveshaft enters the CV joint. In both cases, the splines have twisted forming a helix in the forward direction of the travel. The cone shape fracture is typical of a failure caused by an alternate positive torsional stress along the principal planes when accelerating followed by a negative stress under engine braking, plus a torsional vibrational stress resulting from the shaft stiffness and the natural frequency of the assembly.

 

Both shafts have a fine surface finish, splines are cleanly cut and have smooth transitions from spline to the shaft. Therefore machining is not considered to have contributed to the failure. On the RH shaft, it can be seen that some of the splines are cracked at the transition whilst others have remained ductile suggesting that the grain structure within the shaft may not be of uniform size. The star-shaped appearance of the cone is consistent with crack propagation from the spline roots.

 

Classic Car Developments has stated that the shaft is manufactured from EN24 steel in condition T and the splined ends are induction hardened after machining. It is suggested that this may be the cause of premature failure. EN24T is a nickel, chrome, molybdenum, alloy steel hardened to condition T making it suitable for automotive drive shafts. It has a high tensile strength ( 1000 N/mm2 – 60 tons/sq in.) has good ductility and shock resistance making it a material of choice for many designers. However, in condition T it is not recommended by the steel manufacturers that localised heat treatment processes are carried out. This can cause cracking to occur as seen on some splines and the high tensile properties of the steel can be reduced in the heat-affected zone between the hardened section and the poly-grained conditioned EN24T steel. The following link - https://www.westyorkssteel.com/blog/en24-steel-information-strength-in-steel-for-over-100-years/ - takes you to the West Yorkshire Steel website with a description of EN24T and its properties.

 

From discussions with E J Wards Alistair at CCD has reported that only 2 other driveshafts in several hundred sold have failed in the heat-affected zone suggesting that the secondary heat treatment applied to the two particular driveshafts that were purchased and bought as a pair was in some way different from the normal manufacturing processes and the cause of the premature shaft failure. To prove this conclusively would require a cross-section of the heat-affected zone to be cut, polished, etched, and examined under a microscope to reveal the metallurgical grain structure. E J Wards is currently in discussion with CCD on replacing the shafts and in the interest of gaining further knowledge, I have offered to send my new replacement driveshafts the CCD for examination at the end of next season.

 

Ted Roberts

Stag Owners Club

December 2023"

 

Best to all,

Deryck

[harrytr5]

Many thanks for this Deryck.

I presume Alisdair will follow up on this and a report issued to allay concerns.

Regards Harry

[RogerH]

That's a nice report and set of photo's

 

Roger

[iani]

1 hour ago, harrytr5 said:

Many thanks for this Deryck.

I presume Alisdair will follow up on this and a report issued to allay concerns.

Regards Harry

Alasdair was due to visit EJ Ward this morning, to view my shaft and a pair of Stag shafts, presumably those above as the failure scenarios match what I have heard. I haven't heard back from Alasdair yet.

Ian

[Waldi]

Thanks for sharing this Deryck and Ted.

 

The helix shape of the splined portion suggests the shaft has twisted by a torsional load dominantly “in one direction” but what caused this?

To me it looks like the failure is either caused by a wheel that is very rapidly accelerated or decelerated.

Off course, the load is alternating (braking and accelerating) but I do not understand why an alternating  load explains this failure to be honest, can you explain?

An abrupt “blocked”  wheel while driving during  fast cornering could be a possible explanation, the wheel is slipping and suddenly get grip . The inertia of the shaft itself may be “low” compared to that of the wheel/tyre, but the inertia of the entire drive train is not (think about the stored kinetic energy in a flywheel at 4000 rpm).

About the needed testing:
Hardness testing on several locations (that are not twisted/deformed because this affects the readings) would be my starting point and can be easily done.
If the shaft is cut for testing (to prepare a cross section in the heat treated (splined) area) this needs to be done carefully (slowly and with cooling) to avoid change in structure, but you are likely aware of that.

High hardnesses (from induction hardening) will reduce ductility, the treated surface becomes brittle.

Microscopic examination of the prepared cross section should be part of the inspection.

Have you measured the distance during installation  of the CV shafts (the length from diff flange to brake base plate) as outlined in the installation instructions in the outer and neutral positions of the trailing arm )although I would not expect this kind of failure from that)? Just to rule out that possibility.

I hope the exact cause can be found.

Waldi (a stake holder too).

[PodOne]

31 minutes ago, Waldi said:

Off course, the load is alternating (braking and accelerating) but I do not understand why an alternating  load explains this failure to be honest, can you explain?

 

Hi Waldi

To my way of limited mechanical thinking the alternating load would still be in the same direction of rotation only the torque would vary and support the pictures we see. Repeated enough times it would eventually fail. But that should be well beyond what forces the shaft should see from the drive train in normal use. Unless as you say Waldi the wheel was suddenly brought to a total stop at maximum torque on the shaft, but again I'd expect it not to fail before say the tyre. It must be a sudden event as I suspect you would feel something amiss. Plus for both to fail?

I suspect as others that the hardening process has somehow been compromised and weakened the material. The occasional hard use may have accelerated the failure. For purely road use cars it may never present. Hope not as I have a set fitted, but agree it would be good to understand why. A shame that one set of shafts/500 sold couldn't be sacrificed to see how they are standing up in use after say 5k 10 k 15k etc.

Maybe the manufacture has some batch quality data ?

Andy

[Z320]

Hi,

to keep it simple and not to fit new and different worries I swapped years ago to

- new Goodparts hubs for U joints

- the better U joint quality

- uprated shafts, already used by a friend a number of kilometers 

This is not perfect but good enough and reliable.

Ciao, Marco 

What is uprated on the shafts?

Much bigger diameter gives less force on the surface (torque / bigger radius = less force) and more surface (bigger diameter x 3.14) to bear the forces on.