Review of BMR handling springs (SP083) paired with the Ford Performance track shocks

[J.P.B.]

Just wait until you move the wheel and tire package further up.

10" wide is a pretty good place to be for 265/40's, but for 285/xx or wider you'll want more wheel. At least PP2 spec, though 11" square would likely be better still.

Yeah, it's easy to spend other peoples' money.


Norm

I think PP2 squeezes 305s onto a 10.5" wheel up front? But, I have been nervous about going wider than a 275 or 285 up front on my GT because I just don't know what will safely fit on the 2017; when (of even if) I should use a spacer; and, if there might be unintended consequences to going with too-wide a tire given the original design parameters for the GT (e.g., could I end up causing early failure in the steering rack, or some other issue)?

The old set of 275s on 18x10 +40 were getting to be a tight fit, but clearances were still OK. I have thought about maybe 285 or 295 on the 10" wheels; any thoughts? The 18x10s are nice and light; I would like to stay on those for a little while longer just to save some $.

Many thanks,
Joe

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[Bluemustang]

^^^ Plenty of folks run 305 square with no issues. Check the wheels/tires section.

 

[Norm Peterson]

I think PP2 squeezes 305s onto a 10.5" wheel up front?

Yes, it does. Seems like a good data point to me.

But, I have been nervous about going wider than a 275 or 285 up front on my GT because I just don't know what will safely fit on the 2017; when (of even if) I should use a spacer; and, if there might be unintended consequences to going with too-wide a tire given the original design parameters for the GT (e.g., could I end up causing early failure in the steering rack, or some other issue)?

Even if you stop (pause?) at 285, that's not a strong enough technical reason to permanently limit your wheels to 10" wide.

The old set of 275s on 18x10 +40 were getting to be a tight fit, but clearances were still OK. I have thought about maybe 285 or 295 on the 10" wheels; any thoughts? The 18x10s are nice and light; I would like to stay on those for a little while longer just to save some $.

I get the $ matter, but with that said I'd never go 295 on 10's by active choice (potentially more grip, definitely less rigid support for the tire).

What does "clearances were still OK" mean to you, in inches or mm?


Norm

 

[BmacIL]

305 on 11" square is a typical hot setup. It does fit but you need to run extended studs and at least a 20-25 mm slip-on, hubcentric spacer. Get some R-S4s or NT01 for HPDE work, RE71Rs for autocross or hot laps.

 

[J.P.B.]

Yes, it does. Seems like a good data point to me.



Even if you stop (pause?) at 285, that's not a strong enough technical reason to permanently limit your wheels to 10" wide.



I get the $ matter, but with that said I'd never go 295 on 10's by active choice (potentially more grip, definitely less rigid support for the tire).

What does "clearances were still OK" mean to you, in inches or mm?


Norm

Clearances are mm, not inches, so I am expecting to need a spacer to go wider than 275 while keeping these wheels. Some folks have been very negative about spacers. Seems to me the issue is making sure there is enough length on the wheel studs. I have never had to use a spacer before, so I am struggling with conflicting advice on this issue.

I 100% agree that I don't want to go so wide that the sidewalls are too soft/un-supported. So, 285s with a small spacer might the next step (pause point) when the current tires are done.

My other concern was the idea that too wide a tire could have negative effects in the long run (e.g., damage the steering rack). Much of the discussion in the wheel/tire section centres on looks, and how far a tire sticks out, and not long term consequences. But, if the 2018 PP2 does not have anything special up front to help with the 305's, then I am good with going up that far (although I am not sure I will be all that tolerant of the tramlining at 305; the 275s were tolerable; the 265s are great).

Thanks again,
Joe

 

[J.P.B.]

305 on 11" square is a typical hot setup. It does fit but you need to run extended studs and at least a 20-25 mm slip-on, hubcentric spacer. Get some R-S4s or NT01 for HPDE work, RE71Rs for autocross or hot laps.

I just saw this post after responding to Norm. It seems like this setup should be the goal when I have the funds. I imagine the tramlining will be strongly felt at 305 up front!

Many thanks,
Joe

 

[Norm Peterson]

Clearances are mm, not inches, so I am expecting to need a spacer to go wider than 275 while keeping these wheels.

How many mm? I happen to think that 6mm to the strut is a lot and 10mm is huge, though a tire on less than max-recommended wheel width might need that much.

I 100% agree that I don't want to go so wide that the sidewalls are too soft/un-supported. So, 285s with a small spacer might the next step (pause point) when the current tires are done.

I suspect you'll be able to get away with using 3mm (1/8"). But actual tire dimensions (new vs old) could change that (either way being possible).

Here's a fairly close representation of a 285/35 vs your 275/40 on your 10" wide ET+40 wheels, including sidewall shape. Changes in section width when the actual wheel widths differ from "measuring width" is also modeled.

Norm

 

[J.P.B.]

How many mm? I happen to think that 6mm to the strut is a lot and 10mm is huge, though a tire on less than max-recommended wheel width might need that much.



I suspect you'll be able to get away with using 3mm (1/8"). But actual tire dimensions (new vs old) could change that (either way being possible).

Here's a fairly close representation of a 285/35 vs your 275/40 on your 10" wide ET+40 wheels, including sidewall shape. Changes in section width when the actual wheel widths differ from "measuring width" is also modeled.

Norm

Hi Norm,

Huge thanks for running the wheel+tire numbers!!!! Is the spreadsheet software happen to be publicly available?

Joe

 

[Norm Peterson]

No problem, Joe.

The spreadsheet is of my own construction, and like a few others it seems to be permanently in a state of occasional development. By next week it might have picked up a change, or that might not happen for a couple of years.


Norm

 

[shogun32]

My prior tire set up was a square stance 275 18X10 Bridgestone Sport Comp 2

Bridgestone as a rule makes their tires with a very stiff side-wall (on motorcycle tires too). I don't know where Hankook ranks on that factor but it is something to keep in mind.

 

[repins1911]

Bumping this back up as there is so much good information in this thread. If you are planning major suspension upgrades, take a look, this will help determine what is needed for your application. Thanks to all who have contributed!

 

[baevid]

Most definitely. It's threads like these which make me wish I had gone for the track suspension along with higher spring rates initially but I originally thought it would be too harsh.

 

[buttsy]

I have recently installed the following mods.

1. BMR SP083R springs
2. ford performance track pack struts
3. BMR cradle lockout kit
4. steeda vertical links
5. ford performance toe link bearing
6. superpro rear lower control arm bush
7. superpro camber inner and outer bush
8. superpro front caster bush
9. steeda adjustable rear camber adjustment bracket
10. steeda front camber plates.
11. next will be an allignment by a specialist. The car is absolutely amazing with only an average allignment by a local tyre shop. It rides incredibly smooth yet firm. Definitely not harsh. My evo 7 was harsh. This is amazing.

 

[Brian@BMVK]

I have recently installed the following mods.

1. BMR SP083R springs
2. ford performance track pack struts
3. BMR cradle lockout kit
4. steeda vertical links
5. ford performance toe link bearing
6. superpro rear lower control arm bush
7. superpro camber inner and outer bush
8. superpro front caster bush
9. steeda adjustable rear camber adjustment bracket
10. steeda front camber plates.
11. next will be an allignment by a specialist. The car is absolutely amazing with only an average allignment by a local tyre shop. It rides incredibly smooth yet firm. Definitely not harsh. My evo 7 was harsh. This is amazing.

It's the easy button for a great handling but civil street car.

 

[buttsy]

It's the easy button for a great handling but civil street car.

I had reservations that the car was going to be on the limit for road use. But the second I rolled down my driveway I could tell it was not too harsh. The rebound is firm. But the high speed compression is not harsh at all.
I am still on the original wheels and slippery Pirelli tyres. And stock swaybars. And I couldnt be happier. Well maybe once I get the alignment completed and install a firmer front swaybar and then upgrade wheels and tyres and install engine oil cooler from Harrop. And then take it to the track. lol.
Thanks for all the advice on the forum.

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