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Wheel studs


Roger K
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I know it's possible to get obsessional about these things, but in view of my recent experiences and the safety-critical nature of these parts I'm trying to work out the best parts to fit.

Below is a photo of four wheel studs.  In order from the left, these are:

1) an original rear wheel stud from my car.  Yes, it's bent - I have only just bought this car and it wasn't me!

2) a stud from the new rear hubs as sold by Rimmer's and made by Bastuck (I presume, as they came assembled).  I have had two of these fracture now at the base of the thread before reaching 38ftlbs with a reliable, calibrated torque wrench.

3) a new, replacement stud as supplied by Rimmer's.  It does not appear to be the same as the one supplied fitted to their new rear hub assemblies.

4) a new, replacement stud as supplied today by Canley Classics.

I'd be grateful for folks opinions on which might be best to fit, i.e. either of the two on the right.  The Rimmer's design to me looks good, with a chamfered shoulder at the stressed point - but the finish on Canley's variety looks more original and, frankly, I trust Canley a lot more than I do most suppliers.  Thoughts?

 

IMG_0068.jpg

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Thanks John - I have a set of TR6 studs I had thought of using, but I definitely want to retain the original steel wheels and the chrome centre trim.  That's not possible with the bigger studs, unless I drill and retap the original wheel nuts to 7/16".  And guess what?  The original chrome nuts which take the plastic trim washer have gone No Longer Available, with nobody having any stock and nobody able to give a date for them.  They are only available in stainless (which I'm not really comfortable with in a wheel nut), which I would struggle to drill and tap.  If I drill and tap any of my originals there's no going back.

Maybe stick with the Rimmers (3rd from the left) and see how we go.

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Hi Roger,

Have you reported the broken new studs to Rimmer.  Demand that they look into the problem.  40lbs*ft should not break these studs.

What is happening to the studs once torqued up and in service !!!!

 

Roger

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My take on the options, would come down to No3, It has the smoothest transition at the "critical" point. No 4 could form a notch at the base of the thread much more easily. And "notches" are to be avoided. In certain aplications we would actually Radius undercut to avoid such potential.

Short of actually getting them (Sample) Tensile and Shear destruction tested. I would go with my Gut.

Years ago in College we actually had access to Tensile and Shear tresting gear. Know any College Engineering lecturers?. You never know they might make it part of the course lesson?.

Pete

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Thanks all - I did actually test one of a No.3 on an old hub, brake drum and steel wheel.  It tightened to 60ftlbs with no difficulty, at which point it was getting tricky to hold the wheel.  I have since thrown that stud away...

RogerH, I have sent a full description and photographs to Rimmers and am waiting for them to get back to me.  If the prospect of trading standards doesn't bother them, then I will know who not to buy from in future and will move on to Bastuck.  I may well just duplicate my contacts to Bastuck anyway.  The problem would be if they demand return of the purchased item, i.e. the assembled hub, as I really am not going back down the full-strip-down-with-a-puller route again just now.  And anyway I've removed the studs.

Edit - I've sent it to Bastuck as well.

Will report back.

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3 hours ago, PeteH said:

My take on the options, would come down to No3, It has the smoothest transition at the "critical" point. No 4 could form a notch at the base of the thread much more easily. And "notches" are to be avoided. In certain aplications we would actually Radius undercut to avoid such potential.

Short of actually getting them (Sample) Tensile and Shear destruction tested. I would go with my Gut.

Years ago in College we actually had access to Tensile and Shear tresting gear. Know any College Engineering lecturers?. You never know they might make it part of the course lesson?.

Pete

Hi Peter,

On the #4 stud - between the thread and the  splined diameter there is a short plain section of shank. The thread would be rolled (never cut fr these studs) and have a finish similar to the #3 that 'looks' a better design.  Under normal conditions the force on these studs tensile applied by the torque loading.  Variations in this tensile load is quite small and shock is absorbed by the tyre (usually)  Shear loads would be quite small on our cars.  

I would suggest that studs #3 & #4 are pretty much the same.

 

Roger 

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Hmmm?. The change of section on stud 4, even with a rolled thread looks on the photo as quite abrupt. Any radius at the change of section would be a better design. (Just my View). I`ve turned a few Huge bolts in my time, in  Maritime work, and inspected a few too. and we always paid great atention to the change of section and avoided abrupt changes whenever possible.

Pete

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Hi Peter,

I agree with you. Normal practice would be to have section changes blended in to remove sharp edges.

But for specific application you may be able to take advantage of where the forces are. In the case of a wheel stud it will be all tensile as applied by the torque loading.

Having said that if it were me I would have tapered it.

 

Roger.

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I've discussed this with an old friend who is a retired truck engineer, and has experience of analysing wheel stud failures in commercial vehicles.  He says it can be a bit of a black art, as there are so many variables.  He's also advised me not to use these hubs, as if there is any error in positioning of the studs a lateral load can be placed on the stud as the cone in the wheel is engaged and tightened.  He's also advised me not to try to re-engineer wheel studs, as it's not as simple as it appears!

This makes sense to me, even though I can see no problem.  I think I'll dig out the old ones, hopefully can change with everything on the car (I have an ancient Churchill hub puller for this car), and fit the old ones with new studs fitted.  The old studs are all as bent as the one in my photo, courtesy of Pete's gorillas again, no doubt.

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RogerK

You say you're unhappy with  SS wheel nuts, why is that?

They're not as shiny as a chromed one, but those soon get rust spots.    People speak of 'galling' in SS, but that only occurs with SS on SS, and won't be  problem with SS on mild steel.    There's no need to cut or weld them so the problems of SS there don't apply.     Recent discussion here, on PistonHeads: https://www.pistonheads.com/gassing/topic.asp?h=0&f=20&t=355110

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17 minutes ago, JohnD said:

RogerK

You say you're unhappy with  SS wheel nuts, why is that?

They're not as shiny as a chromed one, but those soon get rust spots.    People speak of 'galling' in SS, but that only occurs with SS on SS, and won't be  problem with SS on mild steel.    There's no need to cut or weld them so the problems of SS there don't apply.     Recent discussion here, on PistonHeads: https://www.pistonheads.com/gassing/topic.asp?h=0&f=20&t=355110

Probably completely irrelevant, but in the past I've had issues with stainless steel being used where the design spec was mild steel.  A conversation I had with a design engineer years ago about differencs in work-hardening patterns put me off, so I've tended to stick with the original material out of choice.  I also have a dislike of engine bays full of stainless fasteners.  I did use some on an early 289 I rebuilt years ago, but they were forever working loose, which stopped when I switched back to mild steel.

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Hi

I seem to recollect a conversation many years ago, where the discussion was ref; SS V`s MS. There was no definitive conclusion, but there was a lot of discussion about the tensile strength of SS being regarded as Inferior (size for size). The elasticity of SS is different to MS too. The issue of SS fasteners coming "slack" was addressed with locktite. Obviously not practical with wheel studs!!!

On 20/02/2021 at 09:55, Roger K said:

if there is any error in positioning of the studs a lateral load can be placed on the stud as the cone in the wheel is engaged and tightened.

My take would be that providing the PCD of (both) the Hub Studs, and Wheel are within tolerance, this would be a highly unlikely cause of issue.

Pete

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Having lost faith in hubs and studs, I decided to refurbish my originals and fit new studs.  I had to remove the ‘new’ hubs, which I did with my heavy old genuine Churchill puller.  Surprise, surprise- half a turn on the puller and the wheel studs sheared at the back and pulled through the hub.  Hence the nuts and bolts in the photo  

 

541CAB1E-7466-4DBB-BB99-33569F1B6A0F.jpeg

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Two did. The mushroom heads splintered and broke off so they started to pull through the hubs. I didn’t risk pulling any further, and swapped them out for 7/16” bolts and nuts. 
I’ve contacted Rimmers, who have sent some replacement studs, and Bastuck, who are looking into it. 
I did ask Rimmers who makes their separate studs, which are different, but no response yet. 

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I suspect that, there will be a few "twitchy" moments for the suppliers, with that sort of evidence of a potential issue. We are in what would be modern day "recall" notice terittory, I suspect. The supliers have to consider their "Duty of Care" situation.

It is almost certainly now down to the material either the composition or it`s heat treatment. NO stud should have sucummed to that. When I took the hubs off the 13/60. The studs gave no sign of stress. They where as tight after the hub was removed as they had been before, Had there been any issue it would have shown as a slackening of the fastenening IMV.

Edit:- Nice old "puller" BTW. Churchill where the "go to" boys back in the day, Not cheap though!.

Pete

Edited by PeteH
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if response is weak i would be inclined to send failed samples to  Rims and Bastuck  with a stiff letter of complaint even trading standards

your contract is with Rims  but with the supplier on board have they had a sample............ this is  just  ruddy dangerous

an article in the Courier would be a good bit of exposure to the problem  you cant be the only one with a problem 

this has the sounds of studs on the cheap from PrC where quality control and specifications dont match up 

the studs have been excessively heat treated to the point they are seriously unsafe and studs are a safety critical part 

pete

 

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The fractures of the bolt heads on pulling with the puller have the same coarse granulated appearance as the fractured stud bases on the other side.

I have mentioned trading standards in both emails to Rimmers and Bastuck, so will see what they say further.  Not sure I am comfortable using the replacement studs Rimmers sent me as they still haven't told me who makes them, or where they were made.  The stepped ones from Canley are looking more attractive all the time!

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56 minutes ago, PeteH said:

Edit:- Nice old "puller" BTW. Churchill where the "go to" boys back in the day, Not cheap though!.

Pete

It's an amazing old thing - I bought it direct from VL Churchill of Northants in around 1980.  It's made of that really smooth black steel and weighs an absolute ton.  It was supplied with a little hessian bag containing a selection of end caps to slip over the shaft it presses against, and a set of tapered nuts to use on the threads - but as they seem to be BSF they haven't fitted anything I've used it on thus far.  I think it does TR hubs, too, as there's a second radius internally and the holes will take a 7/16" stud.  Still got the purchase invoice somewhere - I think it was around £80-90.  I've got another one that's even bigger, but I can't remember what it's for!

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1 hour ago, Roger K said:

 I've got another one that's even bigger, but I can't remember what it's for!

Should we go there?. Let`s just say it`s the "Age Thing"?.

There is a Photo, somewhere which shows my "butch" Home fabricated one. Flange, Scaffold tube and 2 large nuts!. And it worked!!.

Pete

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