Has anyone tried a 245/50/15?
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I suspect you could make it fit just fine, however I'd probably run the 245/45-16 instead.
They have comparable rolling diameters (both hurt gearing pretty significantly), but the 16" will have a stiffer sidewall.
They don't appear to be available in autocross compounds either (if that matters).
Scott
They have comparable rolling diameters (both hurt gearing pretty significantly), but the 16" will have a stiffer sidewall.
They don't appear to be available in autocross compounds either (if that matters).
Scott
I didn't notice they weren't A compounds, thanks.
do you find there is a big performance difference when it comes to side walls?
Right now I'm running 225/45/17's but am looking at running 225/45/15 or 225/50/15 (kumho's) next year. With the gt-s the torque is so low that coming out of slow corners I can use with less rotational mass to get some better acceleration. It's usually not worth going down to 1st and 2nd just doesn't have any pull at low rpm's.
But I must say I like the height of the 225/45/17 because I only had to change into 3rd gear at 1 event this year. I raised my rev limiter to 9000 rpm and with the taller 225/45/17 tires 2nd gear runs out to 72 mph (116 kph) where stock rolling diameter and 8300 rpm ran out to 64 mph (103 kph). A couple years ago I was running 205/40/17 with the stock 8300 fuel cut, they max 2nd at 62.4 mph (100.4 kph) and I was always going into 3rd. The extra rpm and height added almost 10 mph and is really nice for staying in 2nd, cut down a lot on gear changes.
I'm keep the 9000 rpm rev limiter, but would like lighter wheels/tires, and think that some 15x7 kosie k1 racing rims would be nice at 13.5 lbs.
2nd gear speeds
204/40/17 @ 8300 = 62.4 (100.4 kph)
stock @ 8300 = 64.0 mph (103.0 kph)
stock @ 9000 = 69.4 mph (111.7 kph)
225/45/15 @ 9000 = 66.2 mph (106.6 kph)
225/50/15 @ 9000 = 68.8 mph (110.7 kph)
225/45/17 @ 9000 = 72.0 mph (115.9 kph)
I know I will gear down with the 15's and that will help torque and acceleration, as well as the lighter wheels will help acceleration. I'm just not a big fan of going up into 3rd, with the gt-s it can be hard to get back into 2nd nicely without loosing extra time.
So your opinon of the 225/45/15 compared to the 225/50/15 performance would be appreciated.
do you find there is a big performance difference when it comes to side walls?
Right now I'm running 225/45/17's but am looking at running 225/45/15 or 225/50/15 (kumho's) next year. With the gt-s the torque is so low that coming out of slow corners I can use with less rotational mass to get some better acceleration. It's usually not worth going down to 1st and 2nd just doesn't have any pull at low rpm's.
But I must say I like the height of the 225/45/17 because I only had to change into 3rd gear at 1 event this year. I raised my rev limiter to 9000 rpm and with the taller 225/45/17 tires 2nd gear runs out to 72 mph (116 kph) where stock rolling diameter and 8300 rpm ran out to 64 mph (103 kph). A couple years ago I was running 205/40/17 with the stock 8300 fuel cut, they max 2nd at 62.4 mph (100.4 kph) and I was always going into 3rd. The extra rpm and height added almost 10 mph and is really nice for staying in 2nd, cut down a lot on gear changes.
I'm keep the 9000 rpm rev limiter, but would like lighter wheels/tires, and think that some 15x7 kosie k1 racing rims would be nice at 13.5 lbs.
2nd gear speeds
204/40/17 @ 8300 = 62.4 (100.4 kph)
stock @ 8300 = 64.0 mph (103.0 kph)
stock @ 9000 = 69.4 mph (111.7 kph)
225/45/15 @ 9000 = 66.2 mph (106.6 kph)
225/50/15 @ 9000 = 68.8 mph (110.7 kph)
225/45/17 @ 9000 = 72.0 mph (115.9 kph)
I know I will gear down with the 15's and that will help torque and acceleration, as well as the lighter wheels will help acceleration. I'm just not a big fan of going up into 3rd, with the gt-s it can be hard to get back into 2nd nicely without loosing extra time.
So your opinon of the 225/45/15 compared to the 225/50/15 performance would be appreciated.
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I'm not going to address your gearing issues, though I must say your region must have some fast courses if you are running out of second gear over 62-66 MPH!WAR said:
(Sounds fun tho!)Here's been my experience with 225/50/15 vs 225/45/15's. I ran both this year, though not on a Celica, on a 2600 pound MX6. So take what you will from this.
One thing about running 15" wheels is that you will always find lighter wheels than 16" or 17" wheels. You probably already know that, so it's a moot point, but having less rotating mass is a good thing...
But what *I* discovered with the 225/50's on *my* car is that the taller sidewall not only hurt acceleration out of corners (and I have a decent amount of torque for a GS car) but it also seemed to act as a sideways spring in transitional states. (Like slaloms and offsets) While this was fun, making the back end hop around like crazy, it made me slower in slaloms because I had to slow down to keep the back end behind me. (Too often I found the rear end coming around to ask me what to do... :chuckles: )
When I switched to the shorter sidewall 225/45, the problem went away and I could blast through slaloms and offsets as fast as anyone else.
Of course this is info kinda car specific, but I was faster on my practice Azenis (205/50/15) than I was on my 225/50/15 R-Compounds!
So the question begs to be asked, how often are you going over 62 MPH? How much are you digging out of slow speed corners in 2nd? (That's pretty common in autocross, moreso than going over 60 MPH)
Given these parameters alone, I vote for the 225/45!
Of course I don't drive a Celica ...yet.
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