2015 IRS dimension

[PaulProe]

Somewhere in the last year of browsing this and the FFCars forum, I saw a drawing of the new 2015 IRS and dimensions outside the rotors. As I recall, it was a copy of one the the Factory Five drawings that someone photo-shopped the dimensions in.


I've worn out google looking for the info and hoping someone remembers this and can point me to it.


thanks


Paul Proefrock

[CraigS]

I don't remember that picture but I am pretty sure the width is standard Fox Mustang width 59.25.

[PaulProe]

I don't remember that picture but I am pretty sure the width is standard Fox Mustang width 59.25.

Appreciate your comments but the engineer in me says keep looking. I know there is a drawing out there somewhere. Is the 59-1/4" outside the rotors, outside the hats, outside the axle flanges ? Too many variables.

[rich grsc]

Paul, this is the only CAD picture I can find; http://www.ffcars.com/forums/17-factory-five-roadsters/507721-day-17-20-all-new-2015-factory-five-independent-rear-suspension.html.
The 59.25" is wheel mount, hub to hub.

[PaulProe]

Rich, I still am struggling with the hub to hub. 59-1/4" means the wheels have to have a negative offset to keep the track dimension of the car But who knows what that really is.

The original cobras ran a 56" track. Fact Five seems to vary all over the place. I see some comments they recommend 59-1/4" but their latest brochure shows 58-1/2". Then if you go to pin drive wheels, you start subtracting another 5" total to come up with a hub to hub dimension.

So I still continue to search for the lost grail, the hub to hub dimensions for a 2015 IRS w/ pin drive wheels - or do they even offer a pin drive version of the new 2015 IRS? I can't find anything on that either.

Paul

[edwardb]

Rich, I still am struggling with the hub to hub. 59-1/4" means the wheels have to have a negative offset to keep the track dimension of the car But who knows what that really is.

The original cobras ran a 56" track. Fact Five seems to vary all over the place. I see some comments they recommend 59-1/4" but their latest brochure shows 58-1/2". Then if you go to pin drive wheels, you start subtracting another 5" total to come up with a hub to hub dimension.

So I still continue to search for the lost grail, the hub to hub dimensions for a 2015 IRS w/ pin drive wheels - or do they even offer a pin drive version of the new 2015 IRS? I can't find anything on that either.

Paul

Factory Five is not offering the 2015 IRS with pin drive. I remember that specifically from one of the original product announcements.

Maybe someone who has their 2015 IRS build still in process can give you a better measurement. I just tried to a measurement for you, but not easy through the wheels and such. Best I can tell it's very close to 57.5 inches to the outside of both rotors. Looks like 1.75 inches from the outside of the rotor to the wheel mounts. That would put the width at 61 inches. That could off a little but I don't see it being as low as 58-1/2 or even 59-1/2.

FWIW, a couple weeks ago I measured the overall rear track of the 2015 IRS build compared to my solid axle #7750 build. The new IRS build is 1-inch wider. 69-3/4 vs. 70-3/4. Both with 315 tires. Certainly could be some variation in the tires and otherwise, but tends to support the wider dimension.

Hope that helps.