For IRS builds, why not replace front hub studs instead?

[cc2Arider]

For all the discussions about why replacing the IRS studs is a pain-in-the-neck to do, why isn't another solution for IRS builds to replace the front hub studs instead?

I learned in the build class that the IRS studs are adequate for these applications and one of the reasons to replace the studs is so the thread specs match the front studs; i.e., metric vs SAE...

I also just learned on the Forum that the front hubs are a FFR designed part, so why didn't they design it to match the IRS studs? Am I missing something?

Craig C

[Jeff Kleiner]

For all the discussions about why replacing the IRS studs is a pain-in-the-neck to do, why isn't another solution for IRS builds to replace the front hub studs instead?

I learned in the build class that the IRS studs are adequate for these applications and one of the reasons to replace the studs is so the thread specs match the front studs; i.e., metric vs SAE...

I also just learned on the Forum that the front hubs are a FFR designed part, so why didn't they design it to match the IRS studs? Am I missing something?

Craig C

The hubs are not a Factory Five designed part—-they are a Ford part used on 1994 and later Mustangs. I suppose you could change the studs in them but to what end? You’d be changing 10 studs either way.

Jeff

[edwardb]

The 2-piece spindles (as opposed to donor Mustang spindles) are Factory Five designed parts. Maybe that's what you were thinking of. The hubs are standard Mustang parts as Jeff explained. I'm personally always a bit amazed at the forum bandwidth given to changing the studs in the IRS hubs. I've done them a number of times with an impact wrench, greased hardened washers, and a sacrificial nut. If it really bothers you, take them to a machine shop where they can press them in and out for what should be a nominal charge. Easy.

[cc2Arider]

Thanks Jeff and Paul for the replies :)

I suppose I should've been more clear in the background -- why does FFR want the studs replaced anyway? Can't find the answer to that one...

Craig C

[Ted G]

You really don't have to replace the studs.... You'll just have to have two sets of lug nuts. But, I will say there was something therapeutic about changing them out.

[JohnK]

So that they all have the same threads. The IRS studs, as delivered from Ford, are metric threads. If you don't mind having metric lug nuts on the rear and UNC lug nuts on the front you don't need to change them.

[Jeff Kleiner]

… If you don't mind having metric lug nuts on the rear and UNC lug nuts on the front you don't need to change them.

But it’s just a screw up waiting to happen.

Jeff

[JohnK]

Agreed. Not suggesting that this is a good solution - just explaining the rationale for changing them.

[cc2Arider]

Thank you all for the confirmation :)

Is there something intrinsically wrong with the metric lug nut studs, or is it just that the predominance of the fasteners on the rest of the care are SAE?

Craig C

Edit: I suppose I should ask Ford why they changed ;)

[Jeff Kleiner]

Thank you all for the confirmation :)

Is there something intrinsically wrong with the metric lug nut studs, or is it just that the predominance of the fasteners on the rest of the care are SAE?

Craig C

Edit: I suppose I should ask Ford why they changed ;)

Did you buy the FFR replica Halibrand wheels? They come with 20 SAE 1/2-20 lug nuts…

Jeff

[edwardb]

Thank you all for the confirmation :)

Is there something intrinsically wrong with the metric lug nut studs, or is it just that the predominance of the fasteners on the rest of the care are SAE?

Craig C

Edit: I suppose I should ask Ford why they changed ;)

At the risk of overthinking it... (:p) SN-95 Mustangs, the version of front wheel hubs used by Factory Five, were during an era (1993 - 2004) when Ford was still widely using SAE fasteners. The wheel studs and lug nuts at that time were 1/2-20. When Factory Five redesigned their IRS offering in 2015, using the center section and hubs/spindles from the newly released S550 Mustang, Ford was widely using metric, especially for new releases. Wheel studs and lug nuts now M14 x 1.5. Hence the difference. As already stated, the stud change shown in the kit is to make all four corners 1/2-20, and also happens to be the size of the lug nuts supplied with their wheels. There's nothing wrong with either. Just different standards for different times.