What tire will give me a 3.55 gear ratio with my 3.73's

[IMPORTSMOKER]

Im putting a vortech sc trim on, and I know I am going to need a little shorter gear...What size rear tire will give me the effect of having 3.55's??? Im only interested in an 18'' size wheel...

 

[Michael Yount]

It's all simple math - 3.73/3.55 = 1.05 - you need a tire that is 5% taller to get the gear effect. So, something around 27" should fill the bill. Do you know how to do the calcs? Something around a 245/45/18 is gonna be 26.7" tall; 245/50/18 is gonna be 27.4" tall. You're in between. Those are gonna be really heavy, and the extra height may cause clearance issues if you're lowered. No way around that if want the height though. I'd consider a 16" combo unless you need the diameter for bigger brakes -- it'll be much lighter, less unsprung weight means better handling.

 

[QDRHRSE]

blower gears

3.73's should work fine with a stock sized tire and an S-trim. If you plan on 18's you obviously aren't going to do any drag racing so you should be fine. Also, tires for 18's generally are a little taller because the rim is so much taller- even with low profile tires. Don't sweat it.

 

[sleeper89]

to elaborate a little on mr. yount's post:

the stock tire height is 25.63" (225/60/15) or 25.744" (225/55/16).
adding 5% to that = 26.912" or 27.03"......~27" as stated.
you can play with the width/aspect ratio in the link in my sig to try and find what would work best for you in regards to tire sizes. just try to stay as close as possible to the stock tire height to maintain proper braking etc, and know that your speedometer and odometer will no longer be accurate (assuming they were with the gear swap). FWIW a 255/45/18 is 27.03" tall.

-steve

It's all simple math - 3.73/3.55 = 1.05 - you need a tire that is 5% taller to get the gear effect. So, something around 27" should fill the bill. Do you know how to do the calcs? Something around a 245/45/18 is gonna be 26.7" tall; 245/50/18 is gonna be 27.4" tall. You're in between. Those are gonna be really heavy, and the extra height may cause clearance issues if you're lowered. No way around that if want the height though. I'd consider a 16" combo unless you need the diameter for bigger brakes -- it'll be much lighter, less unsprung weight means better handling.

 

[Michael Yount]

Thanks for the extra detail Steve - nicely done. Hadn't noticed your link before - I've been calculating them for a while now....

 

[sleeper89]

Thanks for the extra detail Steve - nicely done. Hadn't noticed your link before - I've been calculating them for a while now....

i'm just glad to have some useful input once in a while

i too have been doing the math for a while, and even more recently as it seems friends etc are coming to me for help....happened across that site and figured it would be a good start to my new sig.

-steve