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Hi I have a 65 TR4A with small wire wheel studs. Will these studs take the standard TR4 steel wheels, or do I have to change the studs for longer ones. I would like to swap around wire and steel wheels periodically if possible. Not keen on fitting spacers on long studs to take wire wheel hubs, enabling me to interchange the wheels.

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Hi Phil,

and welcome to our forum.

Short answer to your question is no. Studs are cut down to accomodate the wire wheel adapter,

and consequently are too short to safely take a standard wheel and normal wheel nut.

If you want to swop between the two, you need the longer stud and then a spacer when using the wire wheel adapter.

John.

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^ + 1

Just to reinforce the above points, if you try and use the short studs for nuts on steel wheels it's not unknown to suffer the nuts pulling through the stud holes. Good engineering practice is to allow 1+1/2 of the stud dia converted into threaded stud length, to be engaged with the securing nuts. Because the spline hub adaptors are secured by narrower nuts than that, it's tempting to think they will work on steel wheels with the short studs...it's been done...and the wheels fall off, don't.

Mick Richards 

Edited by Motorsport Mickey
Misquote on stud length
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White wall tyre (tires) on the trailer - Nice period mod.

I gave a friend a set of TR250 rims with red band tires (tyres) fitted, these are now fitted to his boat trailer ....

Peter W

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I've been driving my 4A (orig specced with wire wheels) 25years 150kmiles with TR6 steel wheels on short studs with standard wheel nuts. Never had any wheels lost or studs pulled or whatever.

Just one data point for your consideration.

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Hi Dave,

yes, indeed it can be done. For normal driving (town/touring etc) the loads on the wheels tend to act through the studs with a shearing force.

The flexibility of the tyres removes a significant amount of sideways bashing.

Thus there is little force pushing on the nuts.

However if you decide to take a few corners on the quick side or kerb the tyres you may be asking for trouble.

Using the short studs on steel wheels is not recommended.

But !!!! if they hold the WW adaptor successfully why not the steel wheels.

Is the steel thickness of a steel wheel significantly thicker than the remaining metakl at the bottom of the adaptor countersink attachment hole. !!!

 

Roger

 

 

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2 hours ago, RogerH said:

Is the steel thickness of a steel wheel significantly thicker than the remaining metal at the bottom of the adaptor countersink attachment hole. !!!

 

No, but the rest of the metal under the nut is!

Pete

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I TRY not to give the benefit of the doubt to items which can kill me or others, …    call me old fashioned.

Mick Richards 

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Hi Pete/Micky,

              I am not giving benefit to anything but am accepting that there are exceptions to the rule and asking the question  -  why!!!

Is there evidence that the shorter stud will always fail - clearly not.

Is there evidence of any short stud failure - don't know.

Can somebody explain the science.

Roger

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Roger, I was just pointing out that the bit of metal at the bottom of the countersink isn't the only part that takes the load. I'm sure that Triumph would have used shorter studs if they thought they would be strong enough - fewer parts to stock and lower cost.

Not really relevant but this discussion reminds I was at a race meeting at Crystal Palace when the Mini-Coopers raced for the first time - almost every Mini lost a wheel due to cracking around the wheel nut. The race was stopped when one of the loose wheels went into the spectators.

Pete

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Hi Pete,

it isn't really a question of the wheel it self but whether the nut will be pulled the stud.

A longer stud will not give any more support to the wheel as such.

You are quite right about the manufacturer not wanting to waste money on needless parts.

So Dave in malaysia has run his steel wheels with short studs for  very long time. This doe not make it right of wrong but it does trigger questions.

 

What sort of load is on the studs/

What is the tensile strength of the studs/nuts/

Why doesn't the whore wire wheel adaptor drop off?  -  ooops!!

 

Roger

Edited by RogerH
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16 minutes ago, RogerH said:

 

Why doesn't the wire wheel adaptor drop off?

 

This. 

A rule of thumb says a nut needs to engage six threads for full strength and to ensure the stud or bolt breaks before the nut. (a related 'rule' is a nut length equal to the thread-diameter, for steel).  Nothing much is gained by going beyond that.  

The standard wheel nut on the long stud engages around eleven threads  and is about 1.5 times the diameter, so looks to be over-sized. Why that is I don't know but perhaps to allow for wear, since the wheels will be removed and re-fitted frequently whereas the WW adaptor will not. 

If the thinner nut used with the WW adaptor is strong enough on the short studs then the full nut should be equally as strong but wear may be a factor. 

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If one compares the cross section of the steel at the stud hole on a steel wheel and on the wire wheel adaptor, one can see that:

- w/w adaptor is a solid piece of steel extending across the whole of the hub

- steel wheel has a curved shape at the stud hole, and as tension is applied by the wheel nut, this curve will be squashed until the wheel bites on the stud

In other words, there is flexibility in the mounting of the steel wheel, and this necessitates having a greater engagement of the nut onto the thread in order to ensure that it cannot become loose i.e. a stud and nut with more threads (see Mick's posting on Friday at 10:08pm) .

With the w/w adaptor, once secured properly, there cannot be any movement whatsoever.

Ian Cornish

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FWIW Triumph changed the size of the wheel nuts pretty soon after introducing the TR2 to Vanguard type as the rims were pulling over the original nuts.

Stuart.

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  • 2 weeks later...
On 10/6/2019 at 3:52 PM, RobH said:

A rule of thumb says a nut needs to engage six threads for full strength and to ensure the stud or bolt breaks before the nut. (a related 'rule' is a nut length equal to the thread-diameter, for steel).  Nothing much is gained by going beyond that.  

The standard wheel nut on the long stud engages around eleven threads  and is about 1.5 times the diameter, so looks to be over-sized. Why that is I don't know but perhaps to allow for wear, since the wheels will be removed and re-fitted frequently whereas the WW adaptor will not. 

I'm not an engineer but would guess another reason for having more than the customary minimum six threads engaged  (or another RoT says  1 x stud diameter) would be as a safety factor, to allow for some working loose (and wobble warning) before complete failure.  I know we all check our wheel nuts every single time trip (ahem...:wub:) but I guess the Triumph engineers were assuming most owners wouldn't be so assiduous.

I just Googled and it looks like manufacturers' recommendations for thread engagement are usually higher than six turns, more usually 8-10 turns. And MSA regs appear to say 1.5 x stud diameter.

Anyway, it's long studs for me, and spacers for when I want to put the wires on.

Nigel

 

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