SLD 15x8 KE Pros 225/45R15 Accelera Sport Xtra(100tw)

[HAHAFiST]

225/45R15. 225/50R15 is too big. Also, lower it.

Crap! I meant 225/45R15, not 225/50. I'm sticking with my swift spring on b8 set up. More curioius if 225/45 in most cases poses no rub issues, I'm on 1" lower thant stock with stock camber settings. I would think its fine and my only decision to make then is wider contact patch/grip with 225/45, or more precision with 205/50.

 

[WannabeST]

In

In general do you recommend 225/50R15 on a 15x8 on mostly stock susp? I’m on lowering Springs (swift spring) but currently don’t have the ability to adjust too much camber. Clearly 205 is the easy choice, but I’m trying to get a little bit extra tread under the car if I can help it.

205 tire on an 8" wide wheel will be faster around a corner vs a 225 on an 8" wide. If you want to run a 225 tire, you would need ideally 9" wide but 8.5" wide would probably suffice

 

[HAHAFiST]

205 tire on an 8" wide wheel will be faster around a corner vs a 225 on an 8" wide. If you want to run a 225 tire, you would need ideally 9" wide but 8.5" wide would probably suffice

Would you consider 225/45 more like training wheels/ a good compromise for daily and track use? Or is 205/50 perfectly fine for daily?

 

[WannabeST]

Would you consider 225/45 more like training wheels/ a good compromise for daily and track use? Or is 205/50 perfectly fine for daily?

I daily my car with 205/50/15 and have zero issues. The only downside I see for myself is no protection on the egde of the wheel to protect against potential curb rash. For daily driving I think the benefits of a 225 on an 8" wide wheel are going to be related to straight line traction, a you should have a bulge on the tire to protect your wheel from damage, and more contact patch in case of rain or other low grip environments like dust or debris.
On the track I see people put too big of a tire on wheels all the time.
For track use I see no benefit of a 225 on an 8" wide wheel. The side wall will have less support due to less stretch/ more bulge, you will spend more money, have more un sprung and more rotating weight, steering response will lower, you are doing the slower setup.
If anyone is faster on track with a 225 on 8" wide vs a 205 on 8" wide they are probably making up all their time in the straights by just mashing the throttle instead of carrying speed through a corner and smoothly getting back on throttle.

 

[HAHAFiST]

I daily my car with 205/50/15 and have zero issues. The only downside I see for myself is no protection on the egde of the wheel to protect against potential curb rash. For daily driving I think the benefits of a 225 on an 8" wide wheel are going to be related to straight line traction, a you should have a bulge on the tire to protect your wheel from damage, and more contact patch in case of rain or other low grip environments like dust or debris.
On the track I see people put too big of a tire on wheels all the time.
For track use I see no benefit of a 225 on an 8" wide wheel. The side wall will have less support due to less stretch/ more bulge, you will spend more money, steering response will lower, you are doing the slower setup.
If anyone is faster on track with a 225 on 8" wide vs a 205 on 8" wide they are probably making up all their time in the straights by just mashing the throttle instead of carrying speed through a corner and smoothly getting back on throttle.

Super helpful. I need to save money anyway and curb rashing has been someting i've avoided quite well over the years. Also, i have a set of stocks with A/S tires i use for daily anyway.

 

[WannabeST]

Super helpful. I need to save money anyway and curb rashing has been someting i've avoided quite well over the years. Also, i have a set of stocks with A/S tires i use for daily anyway.

Same, I have my stock wheels as backups. I have mine with some beat up federal tires right now. But If I want a fast lap, My 15x8 with 205 setup is where it's at

 

[WannabeST]

Super helpful. I need to save money anyway and curb rashing has been someting i've avoided quite well over the years. Also, i have a set of stocks with A/S tires i use for daily anyway.

https://grassrootsmotorsports.com/articles/wheel-width-is-wider-always-better/

This article has some data points that will support my statements. Grassroots has done a couple of these test throughout the years as well as a couple other pages

like tire rack
https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=296&affiliate=HP5

 

[WannabeST]

https://grassrootsmotorsports.com/articles/wheel-width-is-wider-always-better/

This article has some data points that will support my statements. Grassroots has done a couple of these test throughout the years as well as a couple other pages

View: https://youtu.be/1MDq23scaWw?si=QHn67YsGbK5XNHSy


This video also has some good examples

 

[HAHAFiST]

View: https://youtu.be/1MDq23scaWw?si=QHn67YsGbK5XNHSy


This video also has some good examples

I remember this! Stretched was the winner in most cases but tire rack won't recommend it for street use.

 

[WannabeST]

I remember this! Stretched was the winner in most cases but tire rack won't recommend it for street use.

Yep, that tends to be how most fast lap time related modifications go lol

 

[hawyee]

The grassroots test isn't very conclusive, and the 225-45-15 ran the same times as the 205-50-15 so it's not like the 225 is slower. Wish they would have tested the 245-40-15 on the 8" as well, especially a more modern tire with a stiff sidewall like the rt660. The tire rack test is also rwd only so not as relevant to our cars, which desperately need traction getting off the line and digging out of corners when pushing 280wtq while tuned. The biggest issue for us is 15x9 4x108 wheel availability, only options are custom wheels or redrilling hubs. Forum member Slyez (one lap winner) with his nasa tt5 build ran the 245-40-15f/225-45-15r staggered setup and had great success with it on both 15x8 and 15x9 front but the 9 inch wheel is definitely better. I'm running the same with the rt660s currently, but definitely would consider 225 square as well if any of the more competitive autocross tires were made in that size. The 205-50-15 re71rs or a052 might work, but I was half a second slower on a 30 second course with my 215-45-16 re71rs vs the 245 falkens. The wheelspin off the line and coming out of slow corners was drastically more with the 215s. Also I need as much tire as I can get as the scca sth class allowance is 245 for awd, and 265 for fwd. Basically there's so many variables but I think the quickest setup for our cars for most uses and stock fenders is a 245-40-15 on a 15x9 front. I'll be testing the 16x7" 215-45-16 setup vs the 15x8 245-40-15/225-45-15 at MSR Cresson tomorrow with the addition of the new wavetrac as well.

 

[M-Sport fan]

^^^Your 16x7s are RPF1s?

 

[hawyee]

affirm

 

[HAHAFiST]

The grassroots test isn't very conclusive, and the 225-45-15 ran the same times as the 205-50-15 so it's not like the 225 is slower. Wish they would have tested the 245-40-15 on the 8" as well, especially a more modern tire with a stiff sidewall like the rt660. The tire rack test is also rwd only so not as relevant to our cars, which desperately need traction getting off the line and digging out of corners when pushing 280wtq while tuned. The biggest issue for us is 15x9 4x108 wheel availability, only options are custom wheels or redrilling hubs. Forum member Slyez (one lap winner) with his nasa tt5 build ran the 245-40-15f/225-45-15r staggered setup and had great success with it on both 15x8 and 15x9 front but the 9 inch wheel is definitely better. I'm running the same with the rt660s currently, but definitely would consider 225 square as well if any of the more competitive autocross tires were made in that size. The 205-50-15 re71rs or a052 might work, but I was half a second slower on a 30 second course with my 215-45-16 re71rs vs the 245 falkens. The wheelspin off the line and coming out of slow corners was drastically more with the 215s. Also I need as much tire as I can get as the scca sth class allowance is 245 for awd, and 265 for fwd. Basically there's so many variables but I think the quickest setup for our cars for most uses and stock fenders is a 245-40-15 on a 15x9 front. I'll be testing the 16x7" 215-45-16 setup vs the 15x8 245-40-15/225-45-15 at MSR Cresson tomorrow with the addition of the new wavetrac as well.

Given all you've said... seems like just going 205/50R15 RE71RS or RT660 on a 15x8 will get you the better times without the added cost of bigger tire....

 

[hawyee]

Wish I had another set of the same wheels to test back to back but I highly doubt it'd be faster, the recommended max width for a 205 is 7.5". Also the cost savings is negligible a 245-40-15 falkens is like $165 a pop.

 

[M-Sport fan]

Some installers/tire shops will draconianly hold to that 7.5" max wheel width as well, and flat out refuse to install 205s on an 8" wide wheel.

 

[WannabeST]

Wish I had another set of the same wheels to test back to back but I highly doubt it'd be faster, the recommended max width for a 205 is 7.5". Also the cost savings is negligible a 245-40-15 falkens is like $165 a pop.

the 205 on a 7.5 max is more of a street recommendation. There's a ton of parts that will make your car faster and are "off road use only" type of parts

 

[hawyee]

205s may work for your setup but you don't have the torque to warrant a wider tire being that it's not an ST, no offense

 

[WannabeST]

205s may work for your setup but you don't have the torque to warrant a wider tire being that it's not an ST, no offense

I agree that my 90lb ft of torque in my fiesta doesn't require more tire, however this is a problem I used to have on my 515 whp S550 Mustang. I was setting faster lap times on a 265 wide tire vs a 285 tires (same tire) with zero setup changes. I only have an 18x10 wheel so the same concept applies. I would just be wasting money, steering feel, adding un sprung weight, lower mpg, lengthening braking distance, etc. if I would keep buying 285 wide tires for that car.
I go to the track a lot, anywhere from 1-4 times a month, I just don't want to spend extra money on something that has little to no gains, doesn't make sense in my opinion, as an instructor I'm always giving my students advice on how to make going to the track more cost efficient.
(Also this low torque car sets lap times in the same range as many ST owners in here I mean this in the most respectful way, but my streets of willow time is one second off yours with less horsepower, less brakes, less suspension and less tire)

 

[HAHAFiST]

I'd side with the guy who tracks regularly to know what he needs.