Rear Tire & Wheel Size Question for 2014 GT500 with Griggs GR40 SS Setup

[Mulholland Man]

I have a 2014 GT500 (Track Pack), with a Griggs GR40 Suspension that is lowered 2” with a 315 clearance kit and a Watts Link (All Griggs Racing Components). I would like to replace my rear stock wheels and tires with the following:


2 New 18” MT Wheels (I like the wheels shown in the ad below but can’t find these in MT's catalog?).

2 New ET Street R 325/35/R18’s or ET Street 305/40/R18's (note: not sure if 28" OD on this tire will work with 2" lower).


I want to know if this wheel/tire combo will fit my car both it terms of the whee//tire width and the brakes. I have attached below a few pictures of my car and suspension. If anyone on the forum has a Griggs GR40 SS Setup and has some answers, comments or suggestions it would be greatly appreciated.

I've bumped up the RWHP to around 680 with a 2.4" metco pulley & Idler pulley, AB exhaust, VMP CAI, Tune, etc. and while I'm loving the extra torque and the innevitable serpentine glide path from 0 to 60, I need to be able to put down the power. I'm currently running Stock Wheels with Michellin PS Sport Cup 2s. The 2's handle supremely, but off the line is a comedy. 25% throttle and Burnout!

My goal is to find that balance between handling and off the line grip. I know that there have been quite a few other threads on this issue on the forum (I've read them), but nothing dealing specifically with my Griggs setup. My spring rate is 350 on the Coilovers, so I realize its not a drag setup and that the springs and suspension make it easier to spin off the line. I enjoy canyon road driving and the GR40 Handling immensely and don't want to sacrifice that but I also don't want to get smoked by a Tesla or a stock GT in an 1/8 mile stop sign to stop sign frolic.

I welcome anyone's thoughts and suggestions. I would also strongly consider the ET Streets (not the Rs) because I don't want to hit a puddle and lose my life.

Thanks,

Mulholland Man

 

[Mulholland Man]

Update: I really like my stocker wheels. I'm thinking about relocating the 19" fronts to the rear of the car and having them widened by Eric Vaughn to 11.0 in. This way I can run MT ET Street 325/30/R19s on the rear (27.0" diam) on the 11" widened stock rim and I can swap out the rear wheels to the front and run 285/30/R20 Sport Cup 2s on the front (26.8" diam). I saw another thread on swapping front and rear wheels and widening the 19's to this end. Seemed to make some sense (Note: MT doesn't make ET Streets in 325 in the 20" size) but no one really answered the question. Eric said that I could widen the rear wheels out to 11.75 in. max (pushing it) with my Griggs setup w/315 kit but I just want to swap and widen the 19's to 11". To be clear, my goal is not to create a drag car, its to create a street car that can handle well and still put power to the ground (680-700 RWHP plan to stay in that range). I am new to the forum and would really appreciate some feedback if anyone has any experience on these issues.

 

[DeepImpact]

I think that is a cool idea with the wheels and a fun tire combo that should satisfy your needs. Love that rearend setup. Wish I had the coin to do the Griggs stuff.


Sent from my iPhone using svtperformance.com

 

[Mulholland Man]

Griggs does cost but its freaking amazing and worth every penny! I would suggest buying the system piece by piece, starting with the Torque arm (around $700 if memory serves). Eliminated wheel hop and kept me going straight. I had an episode where I was doing about 100 over uneven pavement and my rear end caught air and pitched out hard. Luckily I got it back underneath me, but that was the moment that I knew I needed the Griggs kit. Don't regret it for a second. Best mod I've done so far by leaps and bounds. The Torque arm and watts link are key to keeping that rear end underneath you. I've had four mustangs before this one and never imagined this car could perform like it does. Now I just need the right wheels and tires to put it to the ground and provide the additional stability I need to get out of the slot.

 

[biminiLX]

I have some thoughts but move this to gt500 section not lethal . Will respond later
-J

 

[Mulholland Man]

I have some thoughts but move this to gt500 section not lethal . Will respond later
-J

I'm new here and I'm not sure how to "move a thread". Kind of find this site hard to navigate. NUBE. LOL. Also, if you could provide me with a link to the new members forum that would be awesome. Thanks!

 

[HandsomeRob]

Hey bud. I live in Encino CA 91316. I have a 2014 GT500 also. Im ordering the same Griggs Watts Link and Torque Arm as you. What shop did you use to do the install and the Welding? I'll send you a PM as well. Thanks