Questions about ARP 1/2" studs and Cortex Large wheel kit

Hey All,

I had a question about the ARP 1/2" stud kit or the Cortex Large Wheel fitment kit (http://cortexracing.com/product/large-wheel-fitment-kit-2005-2016-ford-mustang-front/).

1. Since the OEM stud is M14.5 and the ARP stud is a more conventional 1/2" stud size, would there be any issues fitting the stock wheels on the smaller studs?

2. Would you have to get special nuts that can secure wheels meant for both a m14.5 stud and a 1/2" stud? For example, the stock wheels.

3. The OEM wheel torque value is 150 ft lbs. On previous cars that used a 1/2" stud size, torque values were between 88-100 ft lbs. When going to a smaller stud, would we lower the torque value to that 88-100 range?

4. Is the Cortex kit basically, the s550 OEM Hub + preinstalled studs + wheel spacer + lug nuts?

By the way, the BBS Boss 302S 18x10.5 Ford Racing just barely does not clear the barrel of the PP brakes with a 20mm spacer. I was planning to use those as my track wheels. I bought 1x to test fit. I guess it'll make a good decorative table for my garage.

It will fit a non PP car if anyone is interested. I''d be willing to sell it for cheap!

=)

Wheels are hub centric not stud centric. So, bulge nuts would do the trick.

hulk_smash said:

Hey All,

I had a question about the ARP 1/2" stud kit or the Cortex Large Wheel fitment kit (http://cortexracing.com/product/large-wheel-fitment-kit-2005-2016-ford-mustang-front/).

1. Since the OEM stud is M14.5 and the ARP stud is a more conventional 1/2" stud size, would there be any issues fitting the stock wheels on the smaller studs?

2. Would you have to get special nuts that can secure wheels meant for both a m14.5 stud and a 1/2" stud? For example, the stock wheels.

3. The OEM wheel torque value is 150 ft lbs. On previous cars that used a 1/2" stud size, torque values were between 88-100 ft lbs. When going to a smaller stud, would we lower the torque value to that 88-100 range?

4. Is the Cortex kit basically, the s550 OEM Hub + preinstalled studs + wheel spacer + lug nuts?

By the way, the BBS Boss 302S 18x10.5 Ford Racing just barely does not clear the barrel of the PP brakes with a 20mm spacer. I was planning to use those as my track wheels. I bought 1x to test fit. I guess it'll make a good decorative table for my garage.

It will fit a non PP car if anyone is interested. I''d be willing to sell it for cheap!

=)

Click to expand...

1. No issues. I've been running mine since Feb.

2. No. Use the lug nuts supplied by cortex

3. Yes, I think Cortex recommends 90lbs if I remember correctly.

4. Yes.

Here is my build thread with pictures. http://www.mustang6g.com/forums/showthread.php?t=41305

Check with [MENTION=22413]Optimum Performance[/MENTION] for more stud, spacer, and lug nut options as well in the standard size.

Good information on the 302R wheels. I've been trying to find the answer to that.

I have the 1/2" studs in my front hubs and the stock 14mm in the rear. I torque front and back to 100 ft lbs and have no issues after several track days. I don't think you'll need to do anything special wheel wise.

I use the same rim on front as I do back and don't have any problems, other than have to change sockets spending on which nuts i'm working on.

Brent Dalton has the Cortex kit, I just have their 1/2 studs

I run the 1/2" ARP's on my car at 125. We have run OE and aftermarket wheels with our set up. The open lug nuts we use fit all wheels. The conical seat dimension is very similar between 14mm and 1/2. We also have a handful of ARP's 14mm stud. You can also run MSI's 14mm stud. We are working on some more stud choices for 2017. Interesting about the BOSS wheels, the barrel should fit over the brakes. You need about 25mm for strut clearance for those to work and that should push the larger part of the barrel to where the caliper resides.

IMSA/PWC uses 80-90ftlb on any sized stud, granted the wheels only go through one heat cycle. I think if the wheel is fit to the car and torqued properly the torque levels are fine. I'm a fan of clamp load on the higher end.

Optimum Performance said:

I run the 1/2" ARP's on my car at 125. We have run OE and aftermarket wheels with our set up. The open lug nuts we use fit all wheels. The conical seat dimension is very similar between 14mm and 1/2. We also have a handful of ARP's 14mm stud. You can also run MSI's 14mm stud. We are working on some more stud choices for 2017. Interesting about the BOSS wheels, the barrel should fit over the brakes. You need about 25mm for strut clearance for those to work and that should push the larger part of the barrel to where the caliper resides.

Click to expand...

Anyone have a spare 25mm spacer they could send to Hulk to let him try to test fit those wheels? Are there any other 18 x 10.5 wheels out there that fit over the PP 6 pot brembos?

The forgestars do. They can make whatever size and spec yout want. Few guys running 18x11 or 19x11 squared with 315's.

How are they clearing the front with that size? I know the cortex has an offset strut option and with a spacer I have seen them clear 315s. Is that the only option?

PS I have been looking at the Forgestar CF5s in 18x10 or 19x10 to run 285s, but I would prefer to run a 295 or 305 which ideally would need 10.5 or 11.

Here is my logic if you want to cal it that. The Ford Racing 18X10.5" Wheel has about a 49.5mm offset. I compared it to my 19X10 35mm offest wheel with a 285. It clears the strut but I still run about a 16.5mm spacer to kick it out.

So the chart posted I changed the offset of the Boss wheel with a 25mm spacer. I know the TA guys where all running the BBS's and it cleared the brakes.

If you have pictures of the wheel on the car it would be helpful to see how tight the fit is.

Don't hold me to this because I haven't checked the fit myself, I WAS certain the BBS's all cleared. Find something to space the wheel out further to check it.

I used a 20mm spacer my shop had lying around.

If someone has a 25mm spacer lying around, I could test fit it with that and ship it back to you.

bluestang50 said:

How are they clearing the front with that size? I know the cortex has an offset strut option and with a spacer I have seen them clear 315s. Is that the only option?

PS I have been looking at the Forgestar CF5s in 18x10 or 19x10 to run 285s, but I would prefer to run a 295 or 305 which ideally would need 10.5 or 11.

Click to expand...

With the correct offset wheel. I've been running 295/40/18 Hoosier R7's on my Apex EC-7 18x10 +43 wheels with a 1/2 in. cortex spacer. My car has the aFe/Pfadt coilovers, but there is no additional clearance on my coilovers over stock I do not believe(and I test fitted the wheels and tires with the stock suspension still in place initially).

[MENTION=9374]Sock[/MENTION] runs 18x11 CF5's with 315 squared. He does not run a spacer, but while his setup is squared, his front wheels are a different offset than his rears so they can't be rotated. He sells these wheels through Dusold Designs and they are on their website.

[MENTION=15674]Plimmer[/MENTION] is running 19x11 with 305's. His are the same offset so he can rotate them. Due to this, he uses the same 1/2 in. cortex spacer that I do.

Some more random thoughts n options...

Running 6G 19x11ET50 square with 25mm front spacer. Also have 18x11ET44 square. Consider holding out for Apex EC-7 if looking for track wheels. Might be a group buy in the works. Also strongly recommend dual drill spacers 5x114.3 and 120mm...
*edit 305/35 19 MPSS and 305/35 18 NT01

You can make a good spacer from an adapter. I bought a $45 pair of 25mm hub and wheel centric adapters 70.5mm 5x4.5" (114.3) from amazon and then removed and tossed the junk studs in the adapter using a bench vice (couple bucks from Harbor freight in you dont have).
Drilled all the holes out with a 5/8" $12 home depot bit. Hand held or drill press both ok.
Used a Harbor freight $3 step drill bit to chamfer holes for new long shoulder studs. This allows spacer/hub interface to ride on larger stud shoulder(way thicker and much stronger unthreaded). Will post pics if anyone wants.

Caution with amazon adapters as hub bores are usually overcut to leave some slop. I have tighter spacers cut by Lenny that I custom spec but they are $100 a pair plus shipping, dual drill. PM for prints or Ill ask Lenny to give em a part number.
*edit Lenny = Motorsport Tech Spacer Company

I used a couple spare lug nuts to mount the spacer in a manner where I can use the spacer to push old studs out. Pics avail.

The 10.9 grade M14x1.5 Dormans studs are best value and same (if not higher) clamping force vs 1/2" ARP (M14 is larger cross section vs smaller ARP w higher yield strength).

New ARP M14 are supposedly $130? For 10?
ARP 1/2" are $30? for 10? -but you are then stuck with mismatched lugs and lug nuts front and rear or extra work changing rear studs and your OEM lugs are now useless....1/2"sux...

Dormans are $30 Amazon for 10 and you get several options:
610-333 0.625" knurl, big head, little long at 3.56" if running 25mm spacers
610-530 0.626" knurl, 3"
610-437 0.627" knurl, big head, 3"

All of these I dress the knurl down on the bench grinder to 0.624" so they are easier to install and seat without hammering on hubs/bearings or pulling hubs. All heads jig cut. PM if you need a set cut for free, just send studs and email me a label.

Hubs are $50? each from rock auto or white bear lake if you want to press new studs in ahead of time instead of doing on car(you will have to swap hubs and buy castle nuts). Could be faster for you.

Cortex kit is a great option. Check if you need to buy castle nuts to change hubs too. If you do front and rear to 1/2 then you avoid mismatched front and rear studs n lugs issue.

Wish cortex just offered a version of that with M14x1.5 ARP or Dormans... its only $100 in hubs and $30 n studs, add in castle nuts and add $150 labor, $50 spacers n shipping n call it $350?
*Edit! Cortex does offer full parts kits! Many thanks to Cortex for supporting track crowd and making these available

One thing I did when test fitting my setup was go down to lowes a buy a whole bunch of washers.

Then stacked the washers behind the wheel and test fitted my wheels. Measure the height of the washer stack to determine the spacer you want, after you've got the look and clearance you need.

It seems like ET50 is a great starting point for getting the rear to fit, then you determine your spacer using the washers for best front fitment, I have the Cortex offset strut, so the ET50 fits in with a 10mm spacer, and still plenty strut clearance.

One other warning is I have Yokohama AD08R's fitted, and Michelin Sport Cups as my next set, but the Michelins are a definite 1" wider than the Yokohama's. I might need to run a 295 Michelin vs the 305 Yokohama, as the 305 Michelin actually measures out at 325!!!

sigintel said:

You can make a good spacer from an adapter. I bought a $45 pair of 25mm hub and wheel centric adapters 70.5mm 5x4.5" (114.3) from amazon and then removed and tossed the junk studs in the adapter using a bench vice (couple bucks from Harbor freight in you dont have).
Drilled all the holes out with a 5/8" $12 home depot bit. Hand held or drill press both ok.
Used a Harbor freight $3 step drill bit to chamfer holes for new long shoulder studs. This allows spacer/hub interface to ride on larger stud shoulder(way thicker and much stronger unthreaded). Will post pics if anyone wants.

Caution with amazon adapters as hub bores are usually overcut to leave some slop. I have tighter spacers cut by Lenny that I custom spec but they are $100 a pair plus shipping, dual drill. PM for prints or Ill ask Lenny to give em a part number.

I used a couple spare lug nuts to mount the spacer in a manner where I can use the spacer to push old studs out. Pics avail.

The 10.9 grade M14x1.5 Dormans studs are best value and same (if not higher) clamping force vs 1/2" ARP (M14 is larger cross section vs smaller ARP w higher yield strength).

New ARP M14 are supposedly $130? For 10?
ARP 1/2" are $30? for 10? -but you are then stuck with mismatched lugs and lug nuts front and rear or extra work changing rear studs and your OEM lugs are now useless....1/2"sux...

Dormans are $30 Amazon for 10 and you get several options:
610-333 0.625" knurl, big head, little long at 3.56" if running 25mm spacers
610-530 0.626" knurl, 3"
610-437 0.627" knurl, big head, 3"

All of these I dress the knurl down on the bench grinder to 0.624" so they are easier to install and seat without hammering on hubs/bearings or pulling hubs. All heads jig cut. PM if you need a set cut for free, just send studs and email me a label.

Hubs are $50? each from rock auto or white bear lake if you want to press new studs in ahead of time instead of doing on car(you will have to swap hubs and buy castle nuts). Could be faster for you.

Cortex kit aint bad per se, but you are going to need to buy castle nuts to change hubs too. Not sure why they dont include? Then there is mismatched front and rear studs n lugs issue.

Wish cortex just offered a version of that with M14x1.5 ARP or Dormans... its only $100 in hubs and $30 n studs, add in castle nuts and add $150 labor, $50 spacers n shipping n call it $350?

Click to expand...

The reason no manufacturer offers those Dorman studs is because they are designed for dual wheels where two steel rims sit so they have 1" of shoulder. You can use them but with no thread near the hub you are stuck running a spacer.

We have been selling stud and hub kits that include everything HERE for quite some time along with the spacers. We give our Customers several options. Yes the ARP 14mm are way too expensive but we have been selling them to Customers when we can get our hands on them.

We also have had Billet spacers available HERE in mulitple sizes with the correct 70.5mm dimension and have them available with the hub kits.

It drives me a little crazy when I see these posts, the products are out there, we may not have it at Amazon prices but we try to be competitive :cheers: