Converting wheel bolts to studs and nuts

Thanks Chris, i got the suppliers since the last post.
Time for some ordering!

 

4 studs cars are the same

5 Stud Mk3's are M14

 

Cheers Andy

 

Very useful thread - thanks to all who have posted - I have just done my mk2 with - Ford Escort studs from Rally design - the ones with the lip on that press in from the back, the hubs had to be drilled out a little and the lip on the stud flatted on one edge a little - see pic.

 

Possibly useful info for interference splined stud fitting (though I guess ARP ones will come with instructions?).

I picked up this (non-VW) hub with seem to be OEM stud fitments. Game on.



The studs were hammered out, and wouldn't move initially, so pretty tight, but with a decent thwack, the rest were dislodged straight away.



Anyway, the drill hole in the hub was 12.65mm - 12.7mm, whereas the spline cross section was 12.85mm. That's possibly compressed a little from fresh spline peaks. Interference deformation marks are visible in the holes (see above pic). So 0.2mm for interference.

There are parallels with 020 diff bolt kits, and I'll try to get a crownwheel ID measurement to suss the interference used in that application.

The main thing with the ARP studs is to check there's enough meat on the hub for a drill out, as the splined bases look quite wide on them - there's not a lot on the edge of a hub flange, wouldn't want to go to far etc.

 

Just pulling this across from the 020 diff bolt thread:

Nice link, corroborates the info above

 

Considering a stud conversion for my track car, as I'll soon be running 5mm spacers on the rear.

Any thoughts on this setup? Or is it just another cheap and nasty that should be avoided?

 

It's the same Grayston-originated cheapo stuff.

 

Got them a while ago, when I last posted in this thread.
I then lost the invoice and couldn't remember where they were coming from... Moving out now, and the invoice re-appeared. Coincidentally I had to change a hub to my car so I took this picture:

 

How did you get on with the auto inpart studs as I was looking to purchase them along with some spacers. I thought I might as well do it the now as my rear axle is off and my front hubs are off so I can powder coat them....

 

I honestly use them for road only, hence I never got any problem.

 

Illustration of why Grayston studs are crap. Out with the Reeves Mk1 the other week, it was being driven pretty hard through the corners, with a planned tyre change shortly after.

The car came in for the change, I buzzed the offside front studs with the wheel gun and two of them picked up on the threads and the nuts refused to come off, eventually unseating the studs at the base - which were spotted with a MIG! So stuck on, they were sliced off:











The only thing is the studs were pretty dry.

 

It's not great to use a wheel gun on hot threads.
Wheel guns will give the threads major abuse when they are hot. Did you crack them off with a breaker bar first?
Even the best thread 'pull' when they are hot - on the front in particular.
For example - you cant re-torque the bolts/nuts during a pitstop to the same NM as when all was cold'ish. The threads will be too hot to take the same torque.... and a wheel gun will hammer that torque through.

Must be a good gun to break that off! Electric?

 

Conversely, in a pit stop, there is no time for faffing with breaker bars.

Basically they are low quality studs - cut threads not rolled AFAIK - and picking up threads like that bears it out.

 

Sorry. I really didn't mean to contradict your findings

Although I have been told to never use a wheel gun in those situations until the nut/bolts has been cracked-off.
Especially not using the gun to buzz them back up to full torque.... although Im sure the good ones can be adjusted and set to specific torque settings....?
Saying that, many of the major GT/radical teams still re-torque with a torque wrench instead of a gun during pitstops, but they only have one on each wheel, so its a bit quicker And they can usually do it quicker than the driver change.

We have a few men running around. One with a breaker bar while its being jacket up. I don't think it takes much longer to break them off first because it can be done while the jack goes under.
.....unless we are talking about a man on each corner and air jacks.
But then I have never had to do a pitstop in an endurance race where every milli second counts....

 

Cut vs rolled threads

Manufacturers of rolled thread fasteners commonly plate them with cadmium or an environmentally friendly alternative - - less for corrosion resistance than for a low co efficient of friction when dry

If the correct grade of rolled thread plated fastener is unavailable for critical applications such as wheel studs, applying a dry lube such as spray on Molykote or a smear of high melting point grease may prevent thread pickup

It's also worth bearing in mind that the lower the grade of a male or female thread compared to it's mate, the more stress is placed on the first three or four threads of the softer material, causing it to deform and become vulnerable to "picking up" especially if "dry"

Relative to the Reeves' samples, the threads certainly appear cut rather than rolled - - and have the nuts been replaced on their former mating studs, in the same position as when they "seized"?

Regarding wheel studs, the greater the clearance between the stud od and the wheel rim stud hole id, and the greater the distance from hub mounting flange face to the first thread of the wheel nut, the greater the radial forces relative to preferred axial forces acting on the stud, causing it to deflect along it's unsupported length and especially upon contact with the first few female threads of both flange and nut

Considering OE VW engineering, the id of a MkII BBS RA wheel rim mounting bolt hole is 13.25mm and the od of an M12 x 1.5 wheel bolt 11.75mm, which creates 0.75mm radial clearance between the two - - now measure from the rim mounting face to the beginning of the curved female contact face in the rim where the bolt underhead applies pressure, and you'll find it's 7.25mm distant

So, in this instance VW engineers believe a 0.75mm radial clearance between fastener and rim, plus 7.25mm distance between hub mounting face and wheel bolt underhead, allows sufficient flex to accommodate the radial movement between mounting hub and wheel rim - - and bear in mind that fully 7.25mm of flex is possible over a single arc due to the "socket and ball" rim to wheel bolt contact face - - visualise a short whip aerial with the base (hub mounting flange) firmly held and the tip (socket and ball) pushed sideways

Now consider a popular wheel rim substitution where 4x100mm B*W BBS RA style 15x7" rims are fitted for reasons of width and/or offset - - in this case the wheel rim mounting bolt hole is 16.50mm whilst the M12x1.5 wheel bolt od remains at 11.75mm, creating a 2.32mm radial clearance between the two - - again measure from rim mounting face to the beginning of the conical, not ball shaped, contact face in the rim where the bolt's conical underhead applies pressure, and note 10.5mm

However, since the fastener's underhead contact surface cannot pivot at contact mid point a la VW's "ball and socket", all fastener axial flex must therefore take place between the two rigidly held ends 10.25mm apart, creating two arcs bending in opposite directions

Like holding a rod rigidly in clenched fists and trying to bend it by moving one fist up and the other down while maintaining the same horizontal axis at either end

Gottit?

Anyone else looking askance at the forces acting on a wheel bolt or stud after fitting 10 or 20mm wheel spacers with oversize fastener bores and little if any centering bore/bushings?[:^(]

And yes, some B*W 4x100 conical wheel bolts are M14x1.5, but not all - -

Lastly, unfortunately I've lost the link, but once upon a time Toyota had an excellent rolled thread fastener database, by dimension, grade, and part number - - they tend to look scruffy but any we selected worked as expected

 

LcT, apologies: I've finally got round to digesting your reply!

As far as I can see, from the red line downwards, you've raised a theoretical side of fastener flex from rotative and side load forces, but I can't quite fathom what the relevance of it is, unless this contributes to a wheel fastener agitating the threads and causing the degredation above.

On the more apparent point about thread coatings or lubrication of, I agree these threads were fairly dry when this happened. They had also been subjected to a fair amount of heat and rotative side loadings.

I am on the lookout for some better studs, for myself also, as the one above is regularly found in UK outlets under various guises, they're cheap, coatings will be cheap, and they're disconcertingly not a dark metal which hardly inspires confidence in tensile quality.

The dilemma is whether to get some made which may not be coated, with an unthreaded shank diameter of 13mm, or buy some such as these Track-Studs which appear to have the coating side covered, but are threaded throughout:

http://www.apexcompetition.com/ProductInfo/

 

CAD or dwgs a la Daved required!

Apologies to one and all for a tedious post lacking illustrations; I've been remiss in neither downloading and utilising one of the free CAD packages available, nor replacing the stolen Lumix camera with which I could have photographed and posted drawings a la Daved, whose elucidations continue to inspire!

Yes, the "post red line ramblings" were an attempt to expose some of the more subtle factors influencing stud and bolt body flex, the former being particularly vulnerable under the conditions described and therefore a likely contributor to the thread fusing shown on the Reeves' wheel studs

Worst features first, I'd suggest the following: low grade material - length of unsupported stud body vulnerable to flexing - quality of male or female thread form - plated or lubricated threads

Personally, I'd want 4130 or similar steel, rolled male threads, and a knurled stud body with flange so the stud will neither readily unscrew nor pull out of the wheel hub - - as shown on this Irish site www.performancealloys.com/wheel-studs.aspx or www.dropengineering.com or the ARP studs on page 38 of their catalogue http://arp-bolts.com/pages/viewcatalogue.shtml

Keeping the stud to rim mounting hole radial clearance to around 0.50mm +/- 0.25mm and the stud unsupported length to around 8.00mm +/- 2.00mm if an M12 stud, would be another goal

Anyone else notice Porsche and Mercedes also chose a radiused wheel bolt underhead capable of swiveling, ever so slightly in it's mating socket in the wheel rim, thereby relieving some of the axial stress otherwise acting on a wheel bolt, as compared to the conical design employed by, well, almost all other designers?

As an enthusiast long on general experience but short on racecraft, I'm awed by the results achieved by members operating with miniscule budgets and limited technical resources whose enthusiasm and determination clearly pushes nit picking critiques such as mine aside, hopefully without dangerous repercussions

Lastly and in all seriousness, I doubt there's much I could contribute to a team and vehicle as successful and respected as the Reeves' MkI!

 

Thanks LcT, duly clarified. I will look at those links, many thanks.

 

This thread started in April 2005.

Finally, last Thursday I found what I was looking for, over a counter, in Germany's equivalent of Demon Tweeks, 30 kilometres from the 'Ring:








Key features:

- raised centre section for convincing bite up
- clear unthreaded section on on nose, not too long
- black steel, indicating some sort of high tensile quality
- variety of lengths to choose from


Source:

http://www.isa-racing.com/index.php/cat/c885_Universal-Radbolzen.html

Splined versions:

http://www.isa-racing.com/index.php/cat/c886_Einschlagbolzen.html


Goodbye Grayston - you are sheit.


sparrow, those studs you did the GB on circa 2006, who was the mfr?