R Spec wheels with 325s

[Dtmaso]

Couple more.

Nice!

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[S550GTCS]

Couple more.

Beautiful pictures, and really clean car.

 

[xray16]

I noticed the 315 Cup 2 tires are 11.7 inch tread and the 4S 305's are 11.5 inch tread. Both the 295 and 305 30 19's are wider treads that the PSS in 295/305 19.

I am thinking go 295/305 in the 4S or go 305 square. 295 is 11.1 inch tread

 

[reef_guru]

jeff, are those 4s on all 4 or just the rear? cuz those are some pretty wide tires, what did you have to take out to make em fit, lol.

 

[Offboost]

I noticed the 315 Cup 2 tires are 11.7 inch tread and the 4S 305's are 11.5 inch tread. Both the 295 and 305 30 19's are wider treads that the PSS in 295/305 19.

I am thinking go 295/305 in the 4S or go 305 square. 295 is 11.1 inch tread

Agree about the size but the diameter is too small and the car would need to be lowered even more than regular R springs and would scrape really bad but I agree they would work awesome otherwise.

 

[Need4SpeedMotors]

I noticed the 315 Cup 2 tires are 11.7 inch tread and the 4S 305's are 11.5 inch tread. Both the 295 and 305 30 19's are wider treads that the PSS in 295/305 19.

I am thinking go 295/305 in the 4S or go 305 square. 295 is 11.1 inch tread

Yes you can also do the OEM GT350 tire sizes on R-specs.

295/35 | 305/35

Here are some pics of this setup:

 

[oldbmwfan]

I noticed the 315 Cup 2 tires are 11.7 inch tread and the 4S 305's are 11.5 inch tread. Both the 295 and 305 30 19's are wider treads that the PSS in 295/305 19.

I am thinking go 295/305 in the 4S or go 305 square. 295 is 11.1 inch tread

On my SV501 in R spec sizes, I am going with PSS in 305/30-19 all around. Maintains the stock R tire diameter (and slight gearing advantage to the non-R size), and the 305 is appropriate for 10"-11.5" rim range so it should work just fine on the 11.5" wide rear wheels. The tire is also a pound lighter than the 325s and will maintain a similar stretch to the factory 315 PSC2, because the PSS has a more square shoulder.

Tires got delivered this week; should get them mounted over the weekend.

 

[fpa1974]

I have a related question. If I go from the stock GT350 35 profile MPSS on stock wheels to GT350R wheel setup with 30 profile Cup2 what is the actual drop (measured at top of wheel well or equivalent)?

Thanks!

 

[stanglife]

jeff, are those 4s on all 4 or just the rear? cuz those are some pretty wide tires, what did you have to take out to make em fit, lol.

[MENTION=33344]reef_guru[/MENTION] - sorry, I just saw this. All 4S. Did nothing to fit. Wheels are R wheels.

 

[oldbmwfan]

I have a related question. If I go from the stock GT350 35 profile MPSS on stock wheels to GT350R wheel setup with 30 profile Cup2 what is the actual drop (measured at top of wheel well or equivalent)?

Thanks!

Shouldn't it be a half-inch? The tires are 1" shorter overall diameter, so effectively you move the wheel center down 1/2".

 

[fpa1974]

Shouldn't it be a half-inch? The tires are 1" shorter overall diameter, so effectively you move the wheel center down 1/2".

Yes, you are right! On paper the formula is for rear: 305*.35 - 315*.3 = 12.25mm so 1/2" & front: 295*.35 - 305*.3 = 11.75mm so a bit less than 1/2"

I was curious is the theory matches with what happens. I am not sure if anybody actually cared to measure.

 

[oldbmwfan]

Yes, you are right! On paper the formula is for rear: 305*.35 - 315*.3 = 12.25mm so 1/2" & front: 295*.35 - 305*.3 = 11.75mm so a bit less than 1/2"

I was curious is the theory matches with what happens. I am not sure if anybody actually cared to measure.

I was just going by the TireRack reported specs on the tires, stock for stock. Your math on the width*aspect ratio is correct but not all tires in a given size are equal (and tread depth matters). Per TireRack, the overall diameter difference is exactly 1" vs. the 0.5" the math gives you.

 

[reef_guru]

heres a calculator to help

https://www.tacomaworld.com/tirecalc?tires=305-35r19-325-30r19


does re-calibrating the speedo void the warranty?

 

[fpa1974]

I was just going by the TireRack reported specs on the tires, stock for stock. Your math on the width*aspect ratio is correct but not all tires in a given size are equal (and tread depth matters). Per TireRack, the overall diameter difference is exactly 1" vs. the 0.5" the math gives you.

1” diameter difference is correct since the 1/2” was just sidewall difference and it gets multiplied by 2. So not too far. And you are correct that not always the formula reflects the reality. This is why I asked the question in the first place. It should be around 1/2” drop but since I am running the FP lowering springs already I would like to know if possible the exact drop if I make the switch.

 

[JJones]

I’m running 325 on all for with ford performance spring no rubbing at all thing is money! Put the R roll bar on the rear which helped with oversteer might go to a 305 in front this summer

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