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I put 17x9 +24 Mustang Cobra R ('95 style) rear wheels on my '94 SC400 today and was a bit concerned about how few turns the lug nuts made on the studs, so I went looking to see if those wheels take something other than the typical aftermarket conical lug nut. Everything I found indicates they use exactly what I've got.
So, I looked up the studs on AutoZone and found this:
I assume underhead length is the threaded part of the shaft, so the Cobra studs are nearly 0.4" longer. That would explain why I don't have much thread to tighten down on. Is that dangerously little thread, or just borderline?
One of my rear studs is chewed up and needs replacing already. Two of the front studs were in similar shape and have already been replaced, but the rear requires getting the hub off the bearing to be able to push the stud out, so that hasn't been done yet. That would be the time to put on longer studs, if need be.
There's always a snag...
p.s. If a Mod cares to add "wheel" to "studs" in the title, that would clear up any ambiguity with tire studs.
The studs are not that hard to replace...Just did mine. I would recommend you get the right ones for the wheel you are running. For wheel spacers, they even have different length studs for 15mm and 20mm spacer sizes. That says how important the right length is...
The studs are not that hard to replace...Just did mine. I would recommend you get the right ones for the wheel you are running. For wheel spacers, they even have different length studs for 15mm and 20mm spacer sizes. That says how important the right length is...
Any tips on replacing them? (What car was it on?) The fronts were easy, but the rears appeared impossible to remove without the proper bearing press for the hub.
I would think the small difference between something like 15mm and 20mm is more a matter of not having a stud too long for a capped lug nut, which would be the worst possible scenario.
Is there a rule of thumb for how many full turns of the lug nut is a safe minimum?
I found the ARP extended wheel stud option, part #100-7715, but at 2.75" long, it likely wouldn't fit with a closed end cap. Ditto for what I thought looked promising from an eBay seller with a no-name, grade 10.9 set that fits the SC, but the shaft is 50mm -- an exact match for the 1.9687" underhead length for the Mustang studs. However, I compared AutoZone's "underhead" measurements to my spare Dorman #610-266.1 (factory replacement) stud and realized they're talking about the shaft + knurled section. So, the Mustang's 1.97" is actually more like 1.75" of shaft length, so the 50mm one is longer.
This is the best option I've found so far that doesn't require cutting down, which I'd rather not do:
The lone review is awful, but from the sounds of it, I'm guessing operator error, not parts failure. The 35mm shaft is about 6mm more thread than stock, but the 18mm knurl length is an extra 8mm, giving it an additional 14mm extension on the threads for the lug nut to grab onto. That's 0.55", so just a bit more than the 0.4" shy of Mustang length studs I currently am.
I assume it won't present a problem having the knurled section be a bit longer than stock? I can't imagine any part of a wheel would touch up against it, since there's always more opening than the stud diameter.
I'll check this afternoon to see if AutoZone carries Dorman studs in a similar size, but it's a long shot since other stuff I've read says Toyota/Lexus never produced an extended stud that fits these cars, so it's unlikely Dorman would have a factory replacement with the right head shape and knurl diameter, plus thread pattern.
BTW, someone told me today there's a rule of thumb that a safe amount of stud thread, at minimum, is a length equal to the diameter of the stud. That would be about 3/8" in my case, which I'm sure I have at least that much of, but I'll try to figure out some way to measure that (spare stock stud's shaft length relative to wheel's lug nut mating surface) on the two unmounted Mustang wheels... Does anyone know if that's a realistic figure? It seems awfully low to me.
It may not be as bad as thought. I estimate 20mm of thread for the lug nut to grab onto -- maybe just a tad less, since I had to judge how deep the nut sits in the conical seat and how much of the stud's tip is unthreaded -- and a full seven turns of the lug nut. It seemed like less than that because of having to start the nut on the stud with the wrench, being too recessed to line it up by hand.
Thoughts on whether seven turns is sufficient? This Toyota discussion suggests I'm right at the minimum of 6-7, or possibly 8, turns. It also echoes the piece I heard today about diameter of the stud being the minimum length, in which case I'm nearly double the minimum. At least I'm borderline, not dangerously over the line, so I can breathe a sigh of relief while deciding whether it's worth adding extended studs!
AutoZone doesn't carry any Dorman studs in that size. Also, I noticed after post #4 that the eBay seller with the 50mm long stud has FSID Innovation in the measurements photo, so the Amazon link with the 35mm one is likely the true source of their studs.
It might also be worth picking up something like this. The ET (Extended Thread) style lug nut provides an extra 7-8mm worth of thread and is frequently recommended for this scenario, as I've found with more searching. I just need to make sure the extended bit fits in my wheels' hole and doesn't require machining.
I may still pick up a set of ET conical lug nuts for a bit more peace of mind. At 0.61" (15.5mm) diameter on the extended collar, that'll just fit the 16-17mm available. I'll have to figure out some way to estimate if the 0.31" extended depth will fit without bottoming out on the hub, though. Probably best done by placing a standard conical lug in the hole and seeing how deep it seats in the taper... Even if they don't fit, at $13 for 10, it wouldn't be a major waste.
The backs of my 2007 GS430 were a little more difficult than the fronts due to the E-brake hardware. It isn't impossible without removing the hub assembly though. You have to carefully rotate the hub while holding the new bolt at a good angle in the deepest part of the ebrake, and they go in. There are plenty of youtube videos showing the general process. The harder part for me was keeping the wheels from spinning while you "pull" the new bolts into there seats. The job is easy enough that it is deff not worth taking the chance the short bolts...
The backs of my 2007 GS430 were a little more difficult than the fronts due to the E-brake hardware. It isn't impossible without removing the hub assembly though. You have to carefully rotate the hub while holding the new bolt at a good angle in the deepest part of the ebrake, and they go in. There are plenty of youtube videos showing the general process. The harder part for me was keeping the wheels from spinning while you "pull" the new bolts into there seats. The job is easy enough that it is deff not worth taking the chance the short bolts...
And you're sure the same applies to the SC400? I've read other mentions of just having to disassemble the parking brake, but no specifics of how or for which Lexus. My searches have also yielded zilch other than front wheel tutorials. If you have links to any of those videos, that would be a huge help!
My mechanic was stumped by how to do it without hub removal, and he's usually pretty good at figuring stuff out after looking it over. Also, I called Firestone today to get their thoughts on it and they quoted 3 hrs of work ($270) for a single rear stud. And $500 worst case scenario if the bearing gets damaged in the process of removing it from the hub. Gulp. If there's a parking brake trick, the service book doesn't seem to know about it, either.
The only thing I can think of that we maybe didn't try (it's been probably six months, so I can't be certain) is releasing the parking brake to spin the hub and see if that lines up any spots that give the stud sufficient clearance to slip out the back.. That would be a dream solution if so. I would gladly take a flier on the Amazon seller's extended studs (very well reviewed for all the studs they carry for other makes, as I later noticed) if I knew I could remove them later on should they turn out to be significantly lower quality than stock.
I can't say if they are the same. All I can say is that at first I didn't think it would work either, but with the brake off (rotor is off anyways) you can rotate to a spot to barely make it work. Your just going to have to get your hands dirty and try it.
I like getting my hands dirty. It would certainly make a helluva lot more sense to design a hub/brake assembly that has an access point to slip the studs out the back, rather than one which requires potentially destructive disassembly, so I'm really hoping you're right.
Success! Thanks, darinmg, for the push in the right direction. I can now confirm that the SC400 rear wheel studs can be removed without hub disassembly. There's a slot down toward the bottom of the parking brake that they can be angled out of and sideways, and it's got sufficient room to slide the 35mm extended studs back in the same way.
Having all that extra thread bite feels way more reassuring. For $16 shipped for 10 (doing just the rears), I wasn't expecting expedited 2-day shipping or them sending 11 of 'em. Good thing, because one of them got a bit damaged from over-torquing it while putting up more fight than the others to fully seat. Here's several pictures to document the fit. As hoped for, the longer knurled section of the extended studs is perfectly recessed into the rotor hat.
01-10-15, 10:08 PM
how short is too short for wheel studs?
