What gear to run with new wheel combo

[MustangvertGT]

I have 3.73's that ive had for a while sitting in my room. Lately, i purchased some 18x10's out back (295/35/18 tire) and have been told i should go 4.10's now due to the increased wheel size.

First off, my speedo doesnt work. 2000 rpm was about 65-70 before. Today i was being followed by my gf doin that same rpm, and she said iw as doing 80ish. So to cruise at around the speed limit im under 2k which kinda convinces me i just 'bought' myself a lil more room to get 4.10's instead.

a good friend of mine (and hardcore racer) told me that the added rotational size prety much made my stock 3.08's into a 2.73ish gear. I dont want to put them in and regret it later!

Keep in mind, I do a lot of highway driving and dont want to be cruising at a high rpm. I understand itll be higher than now, but you know what i mean.

 

[95CobraMike]

do you have auto or manual?

Wheel size in this case doesnt matter too much.... yes you have increased the wheel size but at the same time you have decreased the tire size...
With a 35 series tire on a 18" rim you are really close to stock wheel and tire height.... If you have a manual id go with a 3.73 gear, if you have an auto, 4.10.

 

[Killercanary]

What is the overall diameter of the new tire? Generally speaking every 1" you change in tire height, you effectively change the gear ratio 12pts. So if you had 3.08's and your new tires are 1" taller than the stockers, your new gear ratio would be around 2.96 and you would be going faster than you used to given the same rpm.

 

[MustangvertGT]

What is the overall diameter of the new tire? Generally speaking every 1" you change in tire height, you effectively change the gear ratio 12pts. So if you had 3.08's and your new tires are 1" taller than the stockers, your new gear ratio would be around 2.96 and you would be going faster than you used to given the same rpm.

thats exactly what im experiencing. At the same engine speed i use to go, I now go faster. Glad i was told how fast i was going before a chp car was behind me to let me know.

Its a manual as well. So wats the verdict??? Stick to the 3.73's??

 

[Killercanary]

The answer depends on what the diameter is of your new tires. Without knowing that its nothing more than a stab in the dark as to what to go with.

 

[BlackVert]

i wouldn't go higher than 3:73 with a manual.

 

[MustangvertGT]

i wouldn't go higher than 3:73 with a manual.

how does your car feel with the 3.73's and the 18's??? I dont know about anyone else, but i noticed a fairly large difference in acceleration. Its slower than before with the added rotational mass. I dont know the weight difference between yours and 18x10 afs bullits. I just dont wanna put the 3.73's in, and just be as fast as i was before. i wanna be faster than before!

edit: just noticed you have heads to boot. Grrr. Im still a weak stock 5.0

 

[BlackVert]

how does your car feel with the 3.73's and the 18's??? I dont know about anyone else, but i noticed a fairly large difference in acceleration. Its slower than before with the added rotational mass. I dont know the weight difference between yours and 18x10 afs bullits. I just dont wanna put the 3.73's in, and just be as fast as i was before. i wanna be faster than before!

edit: just noticed you have heads to boot. Grrr. Im still a weak stock 5.0

it does not lag nearly as much as it did with stock gears. it is noticeably faster. there are 2 things i don't like so much though:

- the rpms i'm turning cruising on the highway. mine is a daily driver.
- the fact that the speedo and odometer are not accurate

other than those 2 things, i love my 3.73s.

that said, i will be going to 3.27s after i finish installing the kenne bell.