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MG Midget and Sprite Technical - Lifespan of a wheel stud

I have some splined hub adaptors that bolt on to the existing wheel studs of a conventional wheel hub. Tapered nyloc nuts secure the adaptors.

I have been running around on these for the past 20+ years and apart from having to occassionally tighten the nylocs a little, these have given me no bother whatsoever.

Took one of the rears off recently and to my horror found that 2 adjacent studs had sheared off. The remaining 2 were still tight. As a result I have now replaced all 16 on the car.

Any perceived wisdom on the lifespan of a wheel stud? I'm guessing that those I replaced could have been 50 years old.

Makes me wonder whether I should continue to put my now MOT-exempt Frogeye through it's annual test... not that there is any certainty that this would have been picked up.

Simon
SA Wood

bolt-on w/wheel adapters are thought by some to be the work of the devil. Probably wouldn't have been found at MOT time. Could have been caused by a sudden shock, maybe driving off a kerb, or a pot-hole even?
David Smith

id think the nyloc gave extra life...nylon dosnt rust like steel on steel threads

ive broken wheel studs during removal on far new transportation

prop
Prop and the Blackhole Midget

If you want wires go for a proper setup and never worry about stud life.
Onno K

Not so easy with a Frogeye.
Dave O'Neill2

Plenty of options for a frog to do it properly.

I lost a wheel once at 120kph and never want to experiance that again.
Imho Simon came really close to that and all would have been avoided with a proper setup.
Onno K

proper set up would be standard bolt on steel or alloy wheels :)

apart from (I assume originally) knock on and off quick for race changes and the 'go-faster-stripes' look of wire wheels what are the advantage(s) of wire wheels?

(if any) (more cooling air gets to brakes???)
Nigel Atkins

There aren't that many options, as quarter-elliptic wire wheel axles are a bit thin on the ground.
Dave O'Neill2

With a frog the rear is not the problem you just have to frankenstein a pair of halfshafts.
The width is no problem with the round arches.
Onno K

Some interesting views - thanks for your comments.

I remain to be convinced that the adaptors in any way contributed to the failures of the studs. There's no contact between stud and adaptor as this is all taken up by the domed nyloc nuts. The studs had sheared flush with the brake drum.

Who knows whether the failure would have occured with conventional bolt-on wheels?

The track of the car is approx 20mm wider on the adaptors so there is undoubtedly more load on the studs as each wheel sits outboard of the bearing by 10mm or so.

Is wheel stud failure once every 24 years an unacceptable risk?

I've fitted new studs all around and will check them more regularly in future.

Oh and the "advantage" of wire wheels for me is that I like the look of them!!

Simon
SA Wood

Simon,
I've lost two studs at least one was from tyre place over-tightening the wheel nuts perhaps to their usual 70 lb/ft instead of the correct 45 lb/ft for the car

the other stud went the same way I'm sure but I couldn't prove that

other fitting wheels or adapters of the wrong PCD I'm not sure it's that common to loose a stud

which of course means many will not post to say of all the ones they know about :)

I was allowing for some just liking the look of wire wheels but wondered about if there where other advantages but thanks for at noticing and replying
Nigel Atkins

"I lost a wheel once at 120kph and never want to experiance that again."


Onno, was that on a motorbike? ;)
Arie de Best

I've got a wire wheel conversion kit on mine. Never had any problems apart from the time I foolishly tried to undo the spinner with the front wheels off the ground and sheared a stud, again flush with the hub. I do check nut tightness periodically and use loctite to be on the safe side!
Matt1275Bucks

If you wish to use "proper" wire wheel fittings with a conventional steel wheel axle you will find that the halfshafts are too short and don't engage to the full extent in the diff (as Onno mentions). I believe that Peter May does higher strength half shafts with addititional length intended to work with the wider steel wheel axle cases.
Alternatively, don't push the half shaft fully home in the wire wheel hub, to leave sufficient shaft to engage at the diff end. Check however as you may find (as I did) the the hub end of the spline is larger in diameter and may foul the end of the axle casing. In that case it needs turning back.
G Williams (Graeme)

Matt - lightbulb moment - wheels off the ground when undoing knock-ons - it's what I have always done - a change of habit is perhaps needed here!

Many thanks.
Simon
SA Wood

Simon
It may or may not be connected but you have to give the spinners a fair old belt to get them moving and I do wonder with the wheel unsupported its just too much lateral force on the studs. Thus other than the stupid occasion above I've always loosened and done the final tightening with the wheels almost fully grounded.
Matt1275Bucks

Simon,

Maybe you should consider installing lager diameter studs. To me, the originals do look silly small.

Charley
C R Huff

But you do need the wheel to be off the ground when you tighten it!
The wire hubs self centering rely on being able to center when tightend.
When the weight of the car is on the wheel the it can not center.
Causing many posible problems.

So go for a proper solution and all will be well
Onno K

The downside of "wheels on the ground" is that a lot of shock is going through the wheel spokes though I suppose that this is damped by the tyres somewhat.

The very process of hammering the suspension whether you have conventional or bolt-on hubs doesn't seem to me to be that attractive.

Of course I have no evidence that any of this caused the studs to fail in the first place, hence my original question about service life of a wheel stud. Perhaps 50 years is far too long whatever they are securing and they should have been replaced before now.

Charley - the studs are deemed OK for securing the conventional wheels - so why not the adaptors?

Thanks to everyone for their contributions
Simon
SA Wood

Simon,

They may have been deemed OK, but you said they broke, and that is not OK.

Perhaps it was metal fatigue, but larger studs would withstand more load or more load cycles before they would fatigue. Perhaps it was a single large shock load, but again, larger studs would take more force to fail them. Perhaps the width of the adaptor increaces the load on the studs, and again ...

I wouldn't do it just on my sayso, but you might want to seek other opinions about using larger studs.

Charley
C R Huff

if a new set are fitted and last another 50 years I don't reckon one would have cause to complain
David Smith

This thread was discussed between 16/04/2013 and 19/04/2013

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