GT350/R and GT500 knuckle comparison.

sigintel

Well-Known Member
Joined
Nov 24, 2015
Threads
57
Messages
2,016
Reaction score
1,036
Location
Republic of Texas, God's Country
First Name
Ray
Vehicle(s)
2018 GT
Awesome thread op! Thanks!

Ford does not want to share changes from a technical competetive perspective. Thats reasonable.

Knuckle being the same means geometry is same but machined to accomdate different rotors.

Can you measure the kingpin angle all 3?
Kingpin effects dynamic camber gain and jacking.
Guessing maybe an increase for 500/R.
That would be huge to know that difference.

 

JAJ

Well-Known Member
Joined
Apr 9, 2016
Threads
4
Messages
1,746
Reaction score
1,387
Location
Vancouver BC
Vehicle(s)
2016 GT350 Track Pack
Ya know, I got to thinking about FP's decision to modify the GT500 knuckle and use it in the GT350R for exactly one model year. On the surface, it makes no sense. Then it dawned on me that there might be more at work here than just reducing tramlining. If you look past the obvious, there are other benefits that, while obscure, are very real and worth considering.

My theory starts with the S197, and it might apply to earlier chassis as well. On the S197, Ford made a spare part that was in the Service Manual and the parts supply chain as "crash bolts". If you were competing in a showroom stock class at the track or autocross, you could use these "factory" pieces to dial in up to 2 degrees of negative camber, something many of your competitors couldn't do because their factory hadn't made the parts for them to do it. Next, consider the 2015+ GT350 and the R. Ford knew that lots of folks would be taking them to the track, and maybe it's just a coincidence, but one way or another, they made it easy to run a square 19x11 setup with factory rear wheels - just put a factory GT350R front hub on your GT350, slip on a 1.5" spacer and the resulting backspacing and offset are an exact match to the GT350R front wheel. Even the lug bolts fit properly. I have a garage full of OEM 19x11's that I use exactly this way. It's like they planned it.

So that brings us to the 2020 GT350R and GT500. Ask not, gentlemen, what the GT500 knuckle can do for the GT350R, but instead ask what the 2020 GT350R knuckle can do for the GT500. Well, if you want to run that garage full of 19" rims on your new GT500, you hustle down to your Ford parts counter and pick up a pair of 2020 GT350R front knuckles and a pair of GT350 calipers in the appropriate color and just bolt them on. Just like crash bolts, these are factory spares available over the dealer parts counter that open up a whole range of brake and wheel options for the serious GT500 driver. Heck, if you go to aftermarket brakes, you can even get down to 18" rims and slicks.

So, on that basis, I think the FP engineers that did this, and got it past the bean counter brigade, deserve a gold star for creativity and service to the performance driving community.
 

Optimum Performance

Well-Known Member
Gold Sponsor
Joined
Mar 13, 2016
Threads
44
Messages
1,308
Reaction score
691
Location
Titusville, Florida
Website
www.facebook.com
First Name
Tommy
Vehicle(s)
'15 GT PP
@Epiphany The control arms are specific to the GT500 Knuckles, it appears the R uses the 500 arms, Aluminum in the forward one.
The ball joint tapers are all over the map, R/500 is also much longer. Sig remained very quiet on what was involved in the actual swap, 100% not using GT350 arms with a 500 Knuckle, the thread would not even protrude to put a nut on it.
 
OP
OP
Epiphany

Epiphany

Well-Known Member
Joined
Oct 11, 2015
Threads
68
Messages
7,141
Reaction score
10,693
Location
Global
Vehicle(s)
I like to disassemble things.
I caught the arm change to aluminum early on. What I haven't done is to measure the effective length of the aluminum arm in comparison to the iron one. That is a great point about the R using the same arm as the GT500 - I had not considered that.

When you say "R/500 is also much longer" are you referring to the ball joints themselves? I would assume yes.

I'll take a closer look at the ball joint areas of the knuckles when I can.
 

shogun32

Well-Known Member
Joined
Feb 8, 2019
Threads
84
Messages
11,945
Reaction score
8,524
Location
Northern VA
First Name
Matt
Vehicle(s)
2019 GT+PP, SS+1LE, 2020 F150
Vehicle Showcase
2
they made it easy to run a square 19x11 setup with factory rear wheels - just put a factory GT350R front hub on your GT350, slip on a 1.5" spacer and the resulting backspacing and offset are an exact match to the GT350R front wheel.
Unless there's something in packaging that makes it impossible, it would have been actually SMART if they had designed the wheels to be uniform from the factory (say ET35, or 40) all around and lengthen/shorted axle and suspension parts to get them to that point. Sure swapping this or that assembly for another allows the end-user to bodge a similar solution but why not design in the RIGHT THING from the get-go? Or at least get the fore-aft offsets within say 15mm and just equip the "pointless" distinction between 350 and 350R with extended studs from the show-room floor. Wanna run rear wheels on the front? Slap on 15mm slide-on spacer and you're done.

I definitely wouldn't hand Ford any trophies for 'creativity' considering they didn't actually exhibit any.
 


JAJ

Well-Known Member
Joined
Apr 9, 2016
Threads
4
Messages
1,746
Reaction score
1,387
Location
Vancouver BC
Vehicle(s)
2016 GT350 Track Pack
Unless there's something in packaging that makes it impossible, it would have been actually SMART if they had designed the wheels to be uniform from the factory (say ET35, or 40) all around...
They did. It's just that you can't get a single offset wheel to work on a GT350 chassis if it's wider than 10" and any offset other than ET37. That spec sits as far outboard as the GT350R rear wheel and as far inboard as the GT350R front rim. So yes, for the 10.5 - 11 - 11.5 rims, it is a packaging constraint that forces the offsets to be different.
 

shogun32

Well-Known Member
Joined
Feb 8, 2019
Threads
84
Messages
11,945
Reaction score
8,524
Location
Northern VA
First Name
Matt
Vehicle(s)
2019 GT+PP, SS+1LE, 2020 F150
Vehicle Showcase
2
for the 10.5 - 11 - 11.5 rims, it is a packaging constraint
you're missing the point. Nobody with a 350 gives a hoot about 10" rims. Ford could/should have designed it so that 11 fit all around with the same offset. Could they really not have shortened the drive axles and rear hub/bearing assembly and found 15mm? Or say lengthened the front arms and assemblies to add 15mm? Overhang is a minor consideration which can be rectified with a different body panel.
 

Optimum Performance

Well-Known Member
Gold Sponsor
Joined
Mar 13, 2016
Threads
44
Messages
1,308
Reaction score
691
Location
Titusville, Florida
Website
www.facebook.com
First Name
Tommy
Vehicle(s)
'15 GT PP
I caught the arm change to aluminum early on. What I haven't done is to measure the effective length of the aluminum arm in comparison to the iron one. That is a great point about the R using the same arm as the GT500 - I had not considered that.

When you say "R/500 is also much longer" are you referring to the ball joints themselves? I would assume yes.

I'll take a closer look at the ball joint areas of the knuckles when I can.
Yes, ball joint stem length, ball joint diameter differs obviously because it is a longer taper to the same size end.

Arms are the same length, we are working on making them fit Magride(PP2) and GT350 knuckles.
 
OP
OP
Epiphany

Epiphany

Well-Known Member
Joined
Oct 11, 2015
Threads
68
Messages
7,141
Reaction score
10,693
Location
Global
Vehicle(s)
I like to disassemble things.
Good stuff!

I marked some centers on the GT350/R knuckles and compared the two. Glean from it how it affects geometry, this is just to show how the centers have been moved.


20200511_184255.jpg

20200511_184502.jpg
 
Last edited:

taylor.crandall1

Well-Known Member
Joined
Jan 23, 2015
Threads
7
Messages
80
Reaction score
24
Location
San Diego
First Name
Taylor
Vehicle(s)
Mustang
Thanks for the info Epiphany.

Can someone tell me the part numbers for the 2020 GT350R knuckles?
 

Alain

Well-Known Member
Joined
Jan 24, 2018
Threads
18
Messages
753
Reaction score
328
Location
Northern NJ
First Name
Alain
Vehicle(s)
2016 Challenger Hellcat / 2019 350R #413
Thanks for the info Epiphany.

Can someone tell me the part numbers for the 2020 GT350R knuckles?
I am pretty sure it is in the video in the first post.

I love listening to guys who truly know engineering talk about this stuff. It's fascinating!!

Thank you Epihany.
 

taylor.crandall1

Well-Known Member
Joined
Jan 23, 2015
Threads
7
Messages
80
Reaction score
24
Location
San Diego
First Name
Taylor
Vehicle(s)
Mustang
I am pretty sure it is in the video in the first post.

I love listening to guys who truly know engineering talk about this stuff. It's fascinating!!

Thank you Epihany.
I enjoy it too.

I tried looking up the number stamped on the knuckle but nothing came up.
 

Stangwipple.csc

New Member
Joined
Aug 4, 2019
Threads
0
Messages
3
Reaction score
0
Location
Miami
First Name
Pedro
Vehicle(s)
Mustang gt 2016
Please guys I need help , I’ve purchased the front GT350R calipers and rotors and GT350 front knuckles , to install on my mustang gt 2018 , but the GT350 knuckles won’t fit , does anyone knows were I can buy the brackets for the GT350R calipers upgrade on a 2018 base gt ? Thanks in advance.
 

shogun32

Well-Known Member
Joined
Feb 8, 2019
Threads
84
Messages
11,945
Reaction score
8,524
Location
Northern VA
First Name
Matt
Vehicle(s)
2019 GT+PP, SS+1LE, 2020 F150
Vehicle Showcase
2
does anyone knows were I can buy the brackets for the GT350R calipers upgrade on a 2018 base gt ?
I could have sworn I saw it on Optimum Performance' site (@Optimum Performance) but now I don't see it. I would start there if for no other reason he's quite conversant on the topic.
 

 
15 - Steeda - 5
Top