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Discussion Starter #1
Hi,

Reading Swallows post has got me thinking.

I have a set of Campagnolo wheels that I had refurbished for my Alfetta but don't use as the wheel hub is too thick so only leaves about 5mm of stud thread for the nut.

Could I have the hub machined thinner to help this or will it then be unsafe?

I'm sure at the time I looked into longer studs but didn't get anywhere but if anyone can help with this better option?

Ta
 

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Longer studs is surely the answer.
 

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Machining the wheel will alter the offset, so in your case, longer studs I think.

In my case, without machining the wheels, which have a zero offset, they'll stick out too far..
 

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Discussion Starter #4
Thanks both, it's a good job I didn't go into engineering!

I've had a look on the usual suppliers sites but I can't see any studs listed, can you buy these separately?

Ta
 

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I think you will struggle to get longer specfic Alfa studs. I've used longer ford studs before on my GTAm rep. They have the same thread but require reaming of the hub to get the correct diameter to accept press fit of the splined part of the stud
 

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Discussion Starter #6 (Edited)
Thanks that may be my last resort.

Highwood do sell standard length ones for the front as they are the same as 105's but there aren't any available for the rears or any longer ones.

Looking on Google there are loads of images of early Alfettas with alloy wheels on so they must know something I don't or maybe my Campagnolo's are thicker that most ??
 

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It's a question for somebody much more qualified in mechanical engineering than me, but why is 5mm not enough?
(Apart from a gut feeling that the wheels are going to come off!)
 

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My gut feeling tells me that with just 4 studs holding a wheel on, I would want at least 10mm and preferably 15mm of thread secured by each 4 nuts. That's based on nothing scientific, just feeling....

I know how easy it is to strip just 5mm of thread with a bit of brute force - 15mm on the other hand is out of my league
 

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Discussion Starter #9
You'll know I'm no engineer but it just didn't look enough, especially as after fitting my new anti roll bar and castor arm ball joints I intend to be chucking it around more than usual.
 

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As a rule of thumb the minimum length of thread for any application is one (stud) diameter; for high-stress applications I'd be looking for 1½ diameters.
 

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Just physics, innit.

The steel stud is, quite literally, elastic. In the elastic region of stretch, the material stretches proportionate to the force applied, and returns to its unstretched state once the force is removed.

What holds the wheel on is elasticity of the stud. The correct torque at the nut stretches the elastic just the right amount to clamp the wheel in place, and also the nut, so it doesn't come undone.

Beyond the elastic region is what is called Young's Modulus. This is the point where further force applied to the material results in a sudden, permanent and disproportionately large stretch of the material as strength collapses This is irreversible, and the steel will now break very easily.

This sensation - of a bolt suddenly giving way and breaking as you overtighten it - will be familiar to most beginner mechanics who think the tighter the better. Overtightening bolts is as bad, or worse than undertightening them. An under-torqued fastening will come loose gradually, which you might notice. An overtightened one will fail suddenly without warning.

If there isn't sufficient stretch (= torque at the nut), there is insufficient clamping force holding the nut. With only 5mm of thread, it will be impossible to set the nut tight enough for the correct stretch because the puny 5mm of thread will strip before that is achieved. It's a racing certainty that with insufficient stretch the nuts will loosen, and quite likely the wheel will fall off, which is inconvenient and best avoided.
 

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Discussion Starter #12
Thanks for the replies chaps, from memory the diameter of the stud must be at least 10mm and even if there's a bit more than 5mm showing there's certainly not 15mm I'd be assured by.

Halftone, what would you say the minimum remaining stud would safely be, I'll stick a wheel on again and measure properly as yes it would be inconvenient if the wheels fell off ?
 

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Thanks for the replies chaps, from memory the diameter of the stud must be at least 10mm and even if there's a bit more than 5mm showing there's certainly not 15mm I'd be assured by.

Halftone, what would you say the minimum remaining stud would safely be, I'll stick a wheel on again and measure properly as yes it would be inconvenient if the wheels fell off ��
There should be enough stud to fully engage the entire thread of the correct nut when it is tightened to the correct torque. There is some latitude here, a safety margin, but that's best kept rather than discarded. So measuring the nut, from it's seat to outer surface will tell you how much the stud should protrude from the wheel. Assuming it's a conical nut as most wheel nuts are, measure from the deepest point, not the edge of the cone.

One other thing: do make sure the new studs are of an adequate tensile rating. Any from a heavier car will be OK. No turning down coach bolts from B&Q, in this location ;)
 

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The standard Nuts on these Cars were particularly long and heavy, so you really don't want to have too little projection.

As mentioned earlier, Ford Studs fit. I bought a set from Burton Power when i needed extra length when fitting some Peugeot Alloys. (a failed experiment, but the studs are still in the hubs.)
 

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As a rule of thumb the minimum length of thread for any application is one (stud) diameter; for high-stress applications I'd be looking for 1½ diameters.
exactly how I understand it to be, if the stud has say a dia. of 15mm, then an absolute minimum 15mm thread has to be protruding.
 

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Beyond the elastic region is what is called Young's Modulus. This is the point where further force applied to the material results in a sudden, permanent and disproportionately large stretch of the material as strength collapses This is irreversible, and the steel will now break very easily.
Er, no. Young's Modulus, or modulus of elasticity, is the ratio of stress over strain within the elastic limit, i.e. it defines how much a material will deform under a given applied force. (See also Hooke's Law)

The point at which deformation changes from elastic to plastic is the yield point. For most steels breakage occurs well into the plastic area - ultimate tensile strength is much higher than yield strength, a property exploited in torque to yield fasteners, or "stretch bolts". For applications such as wheel studs, where fasteners need to be reused, torque to yield is impractical so they work well within the elastic limit.

. . . & that's engineering!
 

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Discussion Starter #17
The standard Nuts on these Cars were particularly long and heavy, so you really don't want to have too little projection.

As mentioned earlier, Ford Studs fit. I bought a set from Burton Power when i needed extra length when fitting some Peugeot Alloys. (a failed experiment, but the studs are still in the hubs.)
It's looking like the longer studs is the safest option, is it these?

http://www.burtonpower.com/grayston-wheel-stud-m12x1-5x63mm-14mm-oversized-spline-ws1215os.html

And will I need new nuts?

Thanks
 

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Thats the sort of thing, however I would keep away from Grayston, they produce some poor quality products. Go for a manufacturer who is prepared to specify the grade of bolt. You want 10.9 grade bolts.
 

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I don't recall them having an oversized spline like that, but it's a while since now. Gut feeling is they are parallel shank.

Regards the make, it might be hobsons choice. Bear in mind they are held into the hub by friction, nothing stops them turning apart from this, so if you have a shank which is a fraction too small and they start spinning you will never get your wheels off again.

I expect scrab is correct about them being 10.9, better to try and ensure your replacements are too.

The fact the nuts are much longer than normal hints to me that they might be a lower grade (8), but who knows!. ( the nuts that is)
 

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I don't recall them having an oversized spline like that, but it's a while since now. Gut feeling is they are parallel shank.
Yes you are correct about the spline. Studying the photo and description is dors say 14mm spline. From memory I reamed the holes out 1/2" (12.7mm)and pressed the studs in. I think this was a touch tight so probably 12.9mm would be better
 
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