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305/30/19 Square on 2019 Bullitt

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33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
I'd like to run 305 30 19s square on my Bullitt Mustang. I've searched forum here and have been on a number of different sites seeking information. I've also been to a couple of tire stores and spoken to Tire Rack as well and I'm still not comfortable with what I'm being told.

I want to run this setup WITHOUT spacers on 19 X 11 wheels. The information that missing is what the ET needs to be front and rear.

I'm running Steeda suspension parts including dual rate springs which lower the car 0.5" from stock.

Is anyone running a similar setup on their S550 Mustang?

TIA for all help and information.
 
Last edited:
89
79
Exp. Type
HPDE
Exp. Level
3-5 Years
New England
I can only tell you what fits fine on my 19x11 square setup with my 305/30r19 supercar 3r tires. Effective front offsets of et25-et22 fit fine. I achieve this by et50 wheels with 25mm-28mm spacers on extended studs, this is the same as if the wheels were 25-22mm offsets with no spacers. You will need more negative camber than stock to tuck under the fender. If you use a camber plate it's not going to be a problem. Camber bolts, or notching the top strut holes, etc. will change the strut clearance so I can't comment on that as I use a camber plate.
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
I can only tell you what fits fine on my 19x11 square setup with my 305/30r19 supercar 3r tires. Effective front offsets of et25-et22 fit fine. I achieve this by et50 wheels with 25mm-28mm spacers on extended studs, this is the same as if the wheels were 25-22mm offsets with no spacers. You will need more negative camber than stock to tuck under the fender. If you use a camber plate it's not going to be a problem. Camber bolts, or notching the top strut holes, etc. will change the strut clearance so I can't comment on that as I use a camber plate.
Hi, thanks. Both tire stores are recommending 19 X 10.5 X ET45 front and rear.
I have camber plates on the car so that's not an issue. The thing is the wheels are not returnable once a tire has been mounted. As you likely know the front is the bigger concern.
 
Last edited:
141
153
Exp. Type
HPDE
Exp. Level
5-10 Years
Arizona
I have the same Steeda springs and I am running 305/30ZR19s on 19X11 ET50 all the way around. -2.7 degrees of camber up front and -1.8 on the rear. Requires a 25mm spacer on the front. I prefer this so I can rotate wheels front/rear.

If you don't want a spacer up front then you need around ET25 or 22 like gwilliams38 said.
 
89
79
Exp. Type
HPDE
Exp. Level
3-5 Years
New England
Hi, thanks. Both tire stores are recommending 19 X 10.5 X ER45 front and rear.
I have camber plates on the car so that's not an issue. The thing is the wheels are not returnable once a tire has been mounted. As you likely know the front is the bigger concern.
Wheel-size.com tells me that setup won't clear the front strut if I use my own setup and strut clearance as a starting point. See if you get any other opinions here on it.

EDIT: Maybe like a 33 or so offset would work on 10.5, but I wouldn't go higher myself without expecting to use a spacer.
 

JDee

Ancient Racer
1,797
2,001
Exp. Type
W2W Racing
Exp. Level
20+ Years
5 miles from Mosport
WADR, why do you not want to use the spacer? A high quality spacer with extended ARP studs is the proven way to do this. You end up with a fully rotatable set of wheels/tires on hardware that is far stronger than OEM. That type of setup has been proven time and again to be reliable, effective, fast, simple and saves money down the road on tires. There are plenty of people on here who use spacers without problems, just buy very good quality ones, not some overseas crap.
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
WADR, why do you not want to use the spacer? A high quality spacer with extended ARP studs is the proven way to do this. You end up with a fully rotatable set of wheels/tires on hardware that is far stronger than OEM. That type of setup has been proven time and again to be reliable, effective, fast, simple and saves money down the road on tires. There are plenty of people on here who use spacers without problems, just buy very good quality ones, not some overseas crap.
What's your opinion about using this type of spacer? https://www.americanmuscle.com/1in-billet-aluminum-wheel-spacers-2015.html
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
WADR, why do you not want to use the spacer? A high quality spacer with extended ARP studs is the proven way to do this. You end up with a fully rotatable set of wheels/tires on hardware that is far stronger than OEM. That type of setup has been proven time and again to be reliable, effective, fast, simple and saves money down the road on tires. There are plenty of people on here who use spacers without problems, just buy very good quality ones, not some overseas crap.
This car is my daily driver and yes that includes winter driving in the metro Chicago area. I'd rather not use a spacer that requires longer studs as that won't work as well with the OEM wheels and winter tires.

I am considering something like this: https://www.americanmuscle.com/1in-billet-aluminum-wheel-spacers-2015.html

That way the spacer is removable for a winter setup on OEM wheels and tires.
 

TMSBOSS

Spending my pension on car parts and track fees.
7,529
5,242
Exp. Type
HPDE
Exp. Level
10-20 Years
Illinois
You appear to be more concerned about how the car looks with winter tires than how safe you will be on track. Been there. I am from Rochelle and know how winters are in Northern Illinois.
The AM bolt on spacer will satisfy your aesthetics concern. They will also be a HAZARD on track. Twice the bolts, nuts and points for flex are not a good idea.
I put longer studs on my Boss years ago. Do they stick out a bit when the spacers are not used? Yes. An open lug nut will be needed. I did NOT need to add longer studs to my GT350R, ford installs them at the factory. Something to think about.
PLEASE DO NOT use the bolt on spacer and go on track. Get a good quality hub centric spacer which uses the extended studs and open lug nuts.
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
You appear to be more concerned about how the car looks with winter tires than how safe you will be on track. Been there. I am from Rochelle and know how winters are in Northern Illinois.
The AM bolt on spacer will satisfy your aesthetics concern. They will also be a HAZARD on track. Twice the bolts, nuts and points for flex are not a good idea.
I put longer studs on my Boss years ago. Do they stick out a bit when the spacers are not used? Yes. An open lug nut will be needed. I did NOT need to add longer studs to my GT350R, ford installs them at the factory. Something to think about.
PLEASE DO NOT use the bolt on spacer and go on track. Get a good quality hub centric spacer which uses the extended studs and open lug nuts.
Thank you for your feedback. I can see your point about the bolt on spacers. I'm not concerned about the esthetics between the two set ups I was more concerned about practicality as I didn't really want to install longer studs. I've done that on another car and it was a PITA especially on the rears. While with the setup we're discussing I won't need to do the rears so . . .

Additionally, I understand that Ford sells a wheel hub assembly fitted with longer studs that will accommodate a 25 mm to 30 mm spacer which is another solution as opposed to installing studs in the existing hub.
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
I have the same Steeda springs and I am running 305/30ZR19s on 19X11 ET50 all the way around. -2.7 degrees of camber up front and -1.8 on the rear. Requires a 25mm spacer on the front. I prefer this so I can rotate wheels front/rear.

If you don't want a spacer up front then you need around ET25 or 22 like gwilliams38 said.
Why are you running so much negative camber up front? On my stock setup I'm running -1.2 up front and -2.0 or so in the rear.
 

TMSBOSS

Spending my pension on car parts and track fees.
7,529
5,242
Exp. Type
HPDE
Exp. Level
10-20 Years
Illinois
More camber is the way to increase grip and reduce tire wear on track. While cornering the tire will roll over wearing the outside of the tire. The inside also will loose contact with the surface of the track. The increased camber counters both of these issues. In a perfect world you have a track alignment and a street alignment. Easy to do with adjustable camber plates but can be an expensive pain if you are paying someone to align your car.. Most of us who track their cars decide on a compromise. We either leave the aggressive track alignment on the car or compromise somewhere between the two. I run 2.5 deg of front camber on both my Boss and GT350. Rear camber on the 350 is 1.5. To go beyond 2.5 in the front you will need to cut the shock tower or add adjustable bolts to the bottom of your struts.
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
More camber is the way to increase grip and reduce tire wear on track. While cornering the tire will roll over wearing the outside of the tire. The inside also will loose contact with the surface of the track. The increased camber counters both of these issues. In a perfect world you have a track alignment and a street alignment. Easy to do with adjustable camber plates but can be an expensive pain if you are paying someone to align your car.. Most of us who track their cars decide on a compromise. We either leave the aggressive track alignment on the car or compromise somewhere between the two. I run 2.5 deg of front camber on both my Boss and GT350. Rear camber on the 350 is 1.5. To go beyond 2.5 in the front you will need to cut the shock tower or add adjustable bolts to the bottom of your struts.
Thanks I'm familiar with how camber helps with cornering, etc. I've run a Genesis Coupe 3.8 R-spec in the past.

I have camber plates on the car so would it still be necessary to modify the shock tower as you've described?
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
I can only tell you what fits fine on my 19x11 square setup with my 305/30r19 supercar 3r tires. Effective front offsets of et25-et22 fit fine. I achieve this by et50 wheels with 25mm-28mm spacers on extended studs, this is the same as if the wheels were 25-22mm offsets with no spacers. You will need more negative camber than stock to tuck under the fender. If you use a camber plate it's not going to be a problem. Camber bolts, or notching the top strut holes, etc. will change the strut clearance so I can't comment on that as I use a camber plate
 

TMSBOSS

Spending my pension on car parts and track fees.
7,529
5,242
Exp. Type
HPDE
Exp. Level
10-20 Years
Illinois
Thanks I'm familiar with how camber helps with cornering, etc. I've run a Genesis Coupe 3.8 R-spec in the past.
Cool.

You can post experience levels in your signature. Helps others understand where you are coming from. Chris added this recently. Sorry if I can across condescending. Have you run at Autobahn? White Genesis Coupe?
I have camber plates on the car so would it still be necessary to modify the shock tower as you've described?
If you want more that 2.5 neg camber, yes. The shock will hit the inside of the opening in the tower much beyond that. Vorshlag has a tool which holds the mandrel of a hole saw nicely when cutting the tower. I made my own one time use guide from wood.
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
Cool.

You can post experience levels in your signature. Helps others understand where you are coming from. Chris added this recently. Sorry if I can across condescending. Have you run at Autobahn? White Genesis Coupe?

If you want more that 2.5 neg camber, yes. The shock will hit the inside of the opening in the tower much beyond that. Vorshlag has a tool which holds the mandrel of a hole saw nicely when cutting the tower. I made my own one time use guide from wood.
No worries I understand your comments were to inform and educate.

Yes, I ran Autobahn in my White Genesis Coupe about 2 years ago. I've also run my cars (Audi, Mini, Genesis and current Mustang) at Blackhawk (Audi, Mini, Genesis & Mustang), Gingerman (Mini, Genesia & Mustang) and Road America (Audi & Mustang).
 

TMSBOSS

Spending my pension on car parts and track fees.
7,529
5,242
Exp. Type
HPDE
Exp. Level
10-20 Years
Illinois
Cool

I may have seen you on track, Not A Novice!!! At Autobahn a white Genesis came past pit out right after someone drug water onto the track. This caused the Genesis to lock up going into one and skid through the grass and stop just short of the wall. Was that you? No damage to the car I saw. Can speak for the drivers suit. LOL
 
33
16
Exp. Type
HPDE
Exp. Level
10-20 Years
Libertyville, il
Cool

I may have seen you on track, Not A Novice!!! At Autobahn a white Genesis came past pit out right after someone drug water onto the track. This caused the Genesis to lock up going into one and skid through the grass and stop just short of the wall. Was that you? No damage to the car I saw. Can speak for the drivers suit. LOL
LOL, no, that wasn't me. Thank goodness. Would have definitely needed a clean pair of shorts after something like that. The event I ran was run by LAPS. I know a number of the guys that run with them, Bob Humphries, Ken Koppitz to name a couple.
 

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