Attention S550 Track Day Drivers

For any serious S550 owners out there, CorteX Racing now offers an ARP long wheel stud solution for the S550. We convert the M14 studs to the conventional 1/2-20 size. These studs press directly into the S550 front and rear hubs with no drilling or machining required. We also include a set of 20 open ended lugnuts or with optional black chrome long, knurled premium lugs. Both the standard and optional lug nuts are 3/4" wrenching to work with wheel that have limited socket clearance.

Compatibility with GT350 and GT350R models has not yet been confirmed. These are intended for S550 GT, ECO Boost, and V6 models.

http://cortexracing.com/product/wheel-stud-kit-2015-ford-mustang-front-and-rear-s550/




Optional Lug Nuts:

Nice to know these are available. Will the HRE FF15's fit on the stock 14mm studs? And will the stock wheels work with these studs and lug nuts?

VooDooBOSS,

Yes, the HRE wheels do fit the M14 OEM studs. Infact, the wheels come with lugnuts included that must be used. The OEM wheels do work with this stud kit.

Can these be installed with the hubs still on the car?

Just ordered a set, will the Gorilla lugs base taper work with OEM wheels as well. I assume yes but wonder if it has been checked. Also what torque value is recommended? 100 ft/lbs is S197 spec and 148 ft/lbs is S550.
Steve

SCGT500 said:

Can these be installed with the hubs still on the car?

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For the rear studs you need to remove the hubs. The studs can be knocked out of the knurl but there is no place open enough to remove the stud much less fit a 3" only stud back in. The rear hubs are removable by taking out the 4 bolts holding the hub bearing retain section. I had to remove the axle nut to all the axle to slide backwards enough to get wrenches and sockets on the bolts. My bolts were tight all the way doing out. You will get a good work out by the time you do both sides. I did one side late in the evening and the other the next day. Two bolts are pretty direct access the other two are much more limited, hence the need to move the axle inward to allow room to access the bolts. I just put FRPP front hubs on so I didn't replace the studs on the front.

voodoo child21 said:

Just ordered a set, will the Gorilla lugs base taper work with OEM wheels as well. I assume yes but wonder if it has been checked. Also what torque value is recommended? 100 ft/lbs is S197 spec and 148 ft/lbs is S550.
Steve

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The gorilla lugs did mount my stock GTPP wheels back up but I have not run the car with them as I am still working on suspension and wheel sizing. I have mounted Forgestar 19x11's and 18 x 12" F14 on the rear. The s197 fitment works on my car (flushes with fender too) but that is with a rear coil over and not with the Factory shock mounted. It might still fit though with he stock shock.

The lugs bevel though looks undersized when placed in the 14mm wheel lug hole. 14mm taper is actually a little larger diameter than the gorilla lug bevel diameter. I would be cautious if running on track with them. The factory hole is much larger so the bevel is not really using the full area for spreading the load. On the plus side torquing to 100 lbs is much nicer than 145 lbs repeatedly!

OCPONY said:

For the rear studs you need to remove the hubs. The studs can be knocked out of the knurl but there is no place open enough to remove the stud much less fit a 3" only stud back in. The rear hubs are removable by taking out the 4 bolts holding the hub bearing retain section. I had to remove the axle nut to all the axle to slide backwards enough to get wrenches and sockets on the bolts. My bolts were tight all the way doing out. You will get a good work out by the time you do both sides. I did one side late in the evening and the other the next day. Two bolts are pretty direct access the other two are much more limited, hence the need to move the axle inward to allow room to access the bolts. I just put FRPP front hubs on so I didn't replace the studs on the front.

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Thanks, I was worried I'd mess w/ the alignment. But see nothing will be taken apart that far.

I had my car at @CorteX Racing for some double secret R&D work this past week. While it was there I had them install the stud kit on my GT350. Fits and works fine. I'm all set for some track wheels as soon as they arrive.

@voodoo child21 did you get yours installed?

VoodooBOSS said:

@voodoo child21 did you get yours installed?

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DIY last Sunday. Fronts on a GT can be done right on the car, rears you have to pull the rear hubs off the carriers. Not that bad and I got the R&R time down to 40 minutes on the 2nd one. I will be very careful removing lugs when at the track 8)

can confirm, have to pull the hubs. Drilling out a stud now, the knurl on the H&R studs leaves some to be desired, ordering the new M14 x 1.5 ARPs for S550 when available

captdistraction said:

can confirm, have to pull the hubs. Drilling out a stud now, the knurl on the H&R studs leaves some to be desired, ordering the new M14 x 1.5 ARPs for S550 when available

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Chris,

The H&R has about a .040" smaller knurl diameter so I can see where it would not have the proper press fit. New hubs are a good idea but I think your originals may be OK. The ARP's are .625" OE Studs have a finer knurl so they measure about .620"(New). ARP's may make you existing hubs salvageable because they use a knurl that is wider and deeper.

I ended up ordering .625 1/2-20 arp studs today. Maybe I can return that hub then.

I should have measured the h&r studs. Had someone else run into my issue? (Spinning stud stripped of its knurled section)

Dumb question here but is the extra strength of the arp truly needed for track work or is it just easier to take the wheels on and off. I just don't like the way the look on my car so prefer the closed lugs.

Jake


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IMO they are needed on the S197 which had noodle stock wheel studs. Elsewhere on TMO that are a few photos of broken wheel studs.

Yes, needed. The stock stud will either break from use or the threads will wear and tear up the lug nuts.

It's likely the stock studs are stronger than noodles....but just slightly.

I agree the stock set up is better looking....until studs break and your car goes into the spin cycle.

I guess I need to upgrade. What do you guys think about cutting the long studs shorter so a closed lug can be used?


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This is a good solution If you cut to proper length. Rule of thumb is to have a square contact area between stud and nut. If the stud is 1/2" in diameter, have at least 1/2" inch of thread contact. A little trial and error should get you there. Count turns between thread start and tight.

Down side. If you swap wheels the depth is likely to change some making stud replacement again a possibility.

Be careful and ensure the nut is not bottoming on the end of the stud.

FWIW we tack weld all of our studs in place, now we do abuse ours more than most, and the impact wrenches used in pit stops are set on kill, but even on the street, I've tacked the studs to the hubs. If you have to remove them you just grind off the weld with a die grinder.

All the broken studs we are seeing are with closed lug nuts. A customer just sheared 3 off the rear of the car drving down the highway. Factory studs, torqued, aftermarket wheels(TSW) which required tiny lug nuts to fit into the wheel holes. Care needs to be taken with closed lug nuts. Looks should always be the last consideration. If the stud is shearing off in the lug nut area the cap of the nut was likely bottoming out and you are getting a false torque. The wheel is not clamped but the stud has been what amounts to being twisted off...think of trying to remove a rusted nut from a bolt, you twist the bolt to the shear point. The wheel not being clamped in place is now flexing at the same point you just overloaded the stud at. Fortunatley the stud fails somewhat in the wheel hole so the wheel hopefully stays attached to the car.

Stay safe my friends!