Putting the 9” together for the 51. I’m going to run 30 or 31 inch tires between 10 and 12.5 width. Which rear bolt pattern and wheel studs are strongest? My disks are drilled for the common options and the wheels are unilugs so I can put in whatever works best. If it matters my wheels are Western slots that were SFI certified back in the day.
Pure speculation here. Using the biggest bolt pattern would spread the load over a large area although I run a 4.75 pattern with the same tires as you and have never had a problem.
In my mind, I don't think it will matter whether it is 4.5", 4-3/4", or 5". The uni-lug will be the weakest link.
I was thinking the same thing until I saw the SFI sticker on the wheels. I’ve never seen certified wheels before. I’m thinking if they certified them they must be good enough for my hot rod. The wheels use shanked nuts wit non-recessed washers.
If they are unilug out to 5x5 pattern then use that with the 1/2 stud, that way the pattern is spread out resting against the wheel, not in no-man's land. Then of course the 1/2 inch stud is thicker than the GM 7/16's, I have a couple cars in 5x4.75 pattern with 1/2 inch ford studs.
It has 1/2 inch Ford studs now at 4 1/2. The wheels and my hubs go out to 5. I think I will call Quick Performance on Monday and see if the have time to do the 5/8 studs at 5 in. I need a second 3rd member with 3.89 or 4.11 gears to get the most out of the tires. If they don’t have enough time to do the studs in a day while I wait I’ll just move the 1/2 inch studs out to 5 and order the 3rd member.
My two cents on certified wheels in general is they can see all kinds of environments after the cert. sticker is put on.
Make sure to fully check your measurements....as far as I know Western did not make 3 pattern in the same wheel, as without a recessed locating washer like E-T or an offset aluminum slug fitted from the backside like Ansen the middle pattern becomes worthless, it is just floating in the holes. Western made what is called dual-fit, 2 patterns....the lug shanks either fit the inner half-moon of each slightly elongated hole or the outer half of each hole. Typical fits are 4-1/2" and 4-3/4"together,... or 4-3/4" and 5"
With as much abuse that wheels with a 4-1/2 inch bolt pattern with 1/2 inch lug bolts get handed on Jeeps why would you want to rewrite the book when what you have is probably as stout as you will have as long as you have high quality studs in it. Unless you are looking at a lot of horsepower and a lot of tire and plan on a lot of slip the foot off the clutch at 4 grand launches I can't see the issue.
I honestly don't think there's any measurable difference in strength between patterns. What's important is good quality studs and nuts and using proper torque. Every lugnut I own only comes off or goes on by hand and gets a final sequence with a torque wrench
Your stud question: Given the same metallurgy, larger diameter studs are stronger. Your pattern question: Assuming the studs are the same diameter for all patterns, the widest pattern you can run will be the strongest in both the torque they will handle, and lateral stability. Look at it on an exaggerated scale, of maybe a mythical 5 on 2" pattern vs wide 5, which is a 5 on 10.25" pattern. Which of those two pattern will rip apart first if you gradually apply unlimited torque?
I would never want two different bolt patterns on one car. I know you probably won't rotate your tires with 10'' rears, but 4.75 bolt pattern wheels are on some damn fast cars.
Unless you have like 700 HP hooking up on a 5500 pound car id run what ever pattern the studs are in the axles at currently or what ever the front is so down the road if you change wheels there not a mismatched set.
Obviously...the larger the better !! 1/2" stud diameter is the "normal" diameter to use. I'm using drive studs in a couple of my cars - The larger "shoulder"...is the same diameter as the "sleeve" on a normal mag wheel lug nut. They screw unto the axle flange, tighten with a nut. Then the outer nut is installed with a "spacer" between the wheel and the lug nut. The stud seats on the corner of the stud and tightened. Then the inner nut helps secure it. Stronger than just...a 1/2" stud. As for lug diameter - 5" is the "normal" diameter for the "large" diameter. Mike
I agree that 1/2 inch studs should be sufficient. Is slightly larger pattern diameter better? Theoretically yes. But consider that a lot of the torque transfer is done by friction of the wheel against the drum. So tight torque on the lugs provides that. There is a big contribution by this friction, it's not just the lugs.
Since I hate being on ladders, I moved the studs on one side. I found out the rotors are drilled for all three, not the axle flange. So I moved them out to 4.75 and apparently Ericnova72 is spot on on these Western wheels. I just need 1/2 inch shank wheel nuts and I can see if I’m happy with the fit. 5/8 Studs are still on the table as the car will be just over or under 4 digit power to the wheels. When I road trip the car, it will likely have a trailer behind it. 2 spares and possibly a fuel cell wouldn’t leave any trunk space for spares, tools, safety gear, and the battery.
If the Western wheels use the same unilug washers as ET wheels used you're better off tossing the shanked style washers. They were prone to working loose, and later ET unilugs came with conical washers to solve that problem. I have ET slots on the back of my gasser and they had shanked washers, and I nearly lost a wheel one day! Driving along fine when I suddenly felt the rear shaking and I immediately stopped to check it. The one rear wheel had lost two lugnuts and other 3 had all backed off! It went from no issue to almost falling off in less than 200 ft.!! I got all new studs, and conical lugnuts, and washers, and changed it all out. Never had another issue in almost a decade since. Even trips down the dragstrip every summer and no wheels getting loose.
The Western wheels are designed without washer slots as the washers sit flat on the face. And as Ericnova72 said, they have slots that only do 2 bolt patterns. The shanks are all the way at one end of the holes depending on the bolt pattern. Then the shanks make contact 180 degrees around their diameter and the flat washers help hold the wheels against the rotor. It must work for them to have been SFI certified. But 5/8 studs are still high on the considerations list.
You can buy a nice heavy duty 3/16 thick flat washer that has a bit of a crown to it, those are what I would want on there. They used to come with Cragars.
I think I read or heard somewhere the 5 on 5 1/2 is the strongest. Almost all of the “older” AA Fuel car wheels are 5 on 5.5 I believe(early Ford pattern until 80-90 truck). Look at the really wide magnesium wheels used in the FUEL RANKS,I believe 5 on 5 1/2 is the winner!!
5/8 studs are the new norm , especially if you think your going to have a 1000 hp at the wheels ? along with beadlocks.
Thanks. Then I guess it depends on all shanks being the same OD? Or for sure being the right OD for the wheels. I've got a drawer full of shank mag wheel lugnuts and my micrometer shows a lot of difference from one to another, so likely Western made unilugs also used specific shanked lugnuts.
I picked up two sets of 1/2 inch shank bolts from the local parts stores. I have also ordered one set of the Crager shank bolts with washers. The OD on both the bolts I have in hand are slightly different. I bolted both wheels on with them and checked for play as I snugged the bolts down. In both cases the wheels needed to adjusted (wiggled back and forth) to allow the bolts to seat inside the oval holes. As the bolts became seated in the holes, the wheels showed less and less play. I didn't have the bolts all the way finger tightened before I could no longer detect movement in the wheel. When snugged not torqued, there was no play at all. I am trying to figure out if I can use plasti gauge to see what the clearance is actually.
I have a bit of a different take since my assumption the patterns have no huge differences in strength. From my experience of searching for a few different wheels that are desirable... Use a Chevrolet pattern - there's are still cool, old wheels available if you decide to change things up. I chose to drill 5x5 and 5x5.5 for my axles to be able to run big Ford pattern but I should've chosen a Chevy pattern instead of the 5x5 because it's easier to find a Chevy pattern in old aftermarket... they just made so many more.
I have them set to 4.75 right now with the stock 1/2 inch 20 threaded wheel studs in them. 5/8 studs are very high on my want list as long as they will fit the wheels and hold them tight enough without needing to modify the wheels. It bothers me that the wheels aren't hub-centric so I might see if I can borrow a mill and make a hub-centric insert for the wheels. But for now I can safely take it down the road once it's all together.
So many super charged OT pony cars running real high HP with 5 on 4.5 BP. Heck, if the BP is the issue, I’d guess GM did it the right way with 6 on 5.5 BP. Or are the studs too close together?
Use whatever is easiest for you and don't overthink it. There are 8-second Foxbodies out there on 4-lug axles with 1/2"-20 studs and Top Fuel cars use a 5x5.5" pattern with 5/8" studs.
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