Wheels Needing Larger Studs?

bigpoppa822

Registered User
So I've come across a deal for the FR500C wheels that I really think I can't pass up. They are Fikse Profil 10 3 piece wheels used on the FR500C race cars. Everywhere that sells them says the stock Mustang wheel studs won't work and they require .625" studs. Being that the wheel will have the same hub bore and I have conical lug nuts, is the change in wheel studs really necessary to run these wheels? I haven't seen a set in person but the pad depth would have to be crazy to warrant different studs.
Stock hub vs. FR500C hub:
m5lp_0604_fr500c_12_z.jpg


The wheel:
http://image.mustang50magazine.com/f/8909867/m5lp_0604_fr500c_13_z.jpg

Any ideas? I'd like to avoid taking all my hubs off and getting new studs put in.
 
I believe that is the diameter of the stud, not length related. I know hi power drag cars will use 5/8 (.625) studs to keep from shearing them due to load at the line. I'm guessing the hi loads of road racing make it wise to do the same. On aftermarket drag wheels like Welds, you use a shanked lug nut/washer for 1/2x20 studs or a washer and nut with no shank for 5/8. Not sure if these wheels will work with small studs, but would not be difficult to replace with larger, just remove, drill, replace. HOWEVER your hubs would then be dedicated to ONLY 5/8 stud wheels. Something to think about, might ahange that great deal into ,MEH:cool:

Adam
 
Think about this. Were you planning to torque the new wheels to a higher value than the one to which you torque your current wheels?

If so, then maybe you need a bigger stud.

If not, then what's the purpose of the bigger stud?

The wheels are held in place by friction between the hub and wheel mounting face. They don't slide all around - if they did, then you would need to tighten the nuts. So if the current studs can take the required torque to keep the wheels in place, then you shouldn't need to change them.

(My amateur opinion.)
 
There are (I'm not sure what they are called) a type of wheel stud adaptor.
It is a larger diameter stud that screws on the stock diameter stud to fit the wheel with the larger holes.
I've seen them on mustangs.
Sorry if its not clear enough.
 
Think about this. Were you planning to torque the new wheels to a higher value than the one to which you torque your current wheels?

If so, then maybe you need a bigger stud.

If not, then what's the purpose of the bigger stud?

The wheels are held in place by friction between the hub and wheel mounting face. They don't slide all around - if they did, then you would need to tighten the nuts. So if the current studs can take the required torque to keep the wheels in place, then you shouldn't need to change them.

(My amateur opinion.)

That's along the lines of my thinking as well but everywhere that sells them doesn't say the bigger lugs are recommended, it says "Requires .625" studs; will not work with stock Mustang wheel studs." And I just don't get why.

http://www.lethalperformance.com/20...-2011-2012-mustang-fr500c-front-wheel-p-35307
 
The studs in the pix definitely look to be a larger diameter and coarser thread. I'm not sure you want the added slop in the stud area. Granted there is a limited amount in all wheels and the beveled nuts help to compensate for that. Using the smaller studs/nut combo could open the door for added slip on take off, which will allow a major shearing of the smaller studs. If you have the $$, I'd play it safe and get the larger stud setup.

You may even be able to design a sleeve to slip over the smaller studs, flared at the outside. If the angles are the same, the flare on the outside that fits the hole on the wheel would create a internal flare to fit the lug & you'll have no gap around the lug and the nut will compress the sleeve against the wheel... I'm not a mechanical engineer but it sounds like it would work in theory...

Rob
 
I don't believe the force holding the wheel on the hub is the reason for larger studs. The added shear strength of the larger stud will take more power or side load forces before failing (ie losing a wheel, seen it happen). There may be a lug nut designed to adapt the larger wheel holes to the smaller stud, but I have never seen one. Maybe check with some of the wheel or lug manufacturers? I wouldn't try to MacGuiver something together, that sounds like a disaster looking for a place to happen:eek:

Adam
 
My thinking is that the stud should NEVER come into contact with the hole in the wheel. So the amount of space around the stud seems irrelevant.

The only way I can see a need for a larger stud is if you go up a large amount in wheel size, like from 16" to 22", in which case there will be a lot more leverage from the wheel rim to the stud. That could overstress a stud and break it. But how many people are already going up wheel sizes without swapping studs?

I wonder if you can contact the manufacturer or seller and ask about this?
 
So I contacted Fikse directly and surprisingly they got back to me almost right away.

The Ford Motorsport wheels cut for 5/8" studs have a 45 degree taper vs a 60
degree taper on standard lug nut. You will need to find 45 degree 1/2" nuts
or recut the wheels to 60 degree taper.
 
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