Reducing tire size?

SL2 Cruiser · 03-01-2006, 05:00 AM

I have a crazy/stupid/possibly smart (but knowing me, its not) idea.. my SL2 auto tops out at around 115 at approx 4.5k rpms. If I was to put on slightly smaller tires, effectively reducing my gear ratio, ya'll think I could increase acceleration and top end speed?

GoldieGoldie97 · 03-01-2006, 05:08 AM

no.

speed limiter rules. don't try to break it.

black97sc2 · 03-01-2006, 05:14 AM

and secondly baring no speed liniter a smaller wheel will essentially lower your top end speed, if you wanted to raise your top end speed you would need larger tires for longer forward distance per revolution of the tire. good thinking, just a little backwards.

SL2 Cruiser · 03-01-2006, 08:59 AM

I see what you're saying, but I was thinking a smaller tire would be needed because (to me) it seems like the engine is straining to get the car up to 115 @ 4.5k rpms, almost like the gearing is too tall, or am I still wrong?

See my truck has the exact opposite problem, the rev limiter and the top speed limiter hit at almost the exact same time, the speed limiter hits first but when I ran oversized tires, the rev limiter would kick in first.

my99sl1 · 03-01-2006, 02:53 PM

why would you want smaller tires?

are you thinking of getting like 13's?

shady804 · 03-01-2006, 02:56 PM

Quote:

Originally Posted by my99sl1

are you thinking of getting like 13's?

EWWWW!!!

Stick with stock wheels!!

SL2 Cruiser · 03-01-2006, 06:09 PM

No, I want to stick with stock 15's but was just thinking about a smaller sized tire to go on the rim... Read the entire thred.

E-DUBB · 03-01-2006, 07:49 PM

my 02" SL1 backed down @ 110mph..........and yes it did hit 110mph. i was on the clear freeway........ then some stupid dude i zapped in a mustang thought i was racing him when i did that and he almost rear ended a 18 wheeler. idiot

Sleeper SL2 · 03-01-2006, 11:59 PM

Smaller wheels make the top speed lower because the wheel can only rotate so much and smaller wheels max out speed quicker.

Satyllac · 03-02-2006, 12:32 AM

Quote:

Originally Posted by SL2 Cruiser

I see what you're saying, but I was thinking a smaller tire would be needed because (to me) it seems like the engine is straining to get the car up to 115 @ 4.5k rpms, almost like the gearing is too tall, or am I still wrong?

See my truck has the exact opposite problem, the rev limiter and the top speed limiter hit at almost the exact same time, the speed limiter hits first but when I ran oversized tires, the rev limiter would kick in first.

If you can do 115 MPH @ 4,500 RPM now, and you put on a smaller diameter tire, you'll do 110 MPH @ 4,500 RPM, or 108 MPH @ 4,500 RPM. However, your speedometer will still tell you that you're going 115.

Smaller tire circumference = Lower actual speed at X,XXX RPM.

Whether you've got a 155/35 or a 245/70 tire... Your speedometer is going to read the same MPH, since it's based on the engine speed as far as I recall. It's your actual speed that will change. In which case, if you had two engines, with identical transmissions, running at exactly the same speed, in the same gear, the 155/35 would be pulling you at a very slow speed, and the 245/70 would be cruising along at a significantly higher speed.