i want to upgrade to 285-75-16 MTR's but i have 3.90's . when i regear to 4.56's it wont be a problem but untill then you think it would be cool or what...

any input is good input
thankyou

-Trevor

 

gas mileage will go down, power would go down.

You have the 5speed so it should be fine, but you will be at a loss of power and acceleration. 4.56 are nice is this your DD?

If it isn't i would go to 4.88's incase you run bigger, and you will like the better power.

 

i thought the 5spds came with 4:10s ?

 

according to steve's chart (sonoran steel) mine is a 3.90 I think, and my rig is a 5spd. I would like to run 285's eventualy but I think it will be a dog if I dont regear

 

im running 285/70/17. and i have 3.90's, its not that bad at all and i have a 2.7.... you should be fine with a 3.4... i get decent mpg's to, 20 mpg's normal driving, and 24 highway.

 

yes this is my dd ive learned if you look at the inside of your door panel and it says 225-75 than you have 3.90's or lower. i think its a retarded package but oh well s.h.i.t. happens right....

 

My 97 came with 3.90's and its an auto. I have 33's on it and honestly the power isnt too bad. It lagged some pulling grades, and I always had to kick it out of O/D to get up the hills. I just put in a 4.56 rear diff this last weekend and it does make a big diff. If you drive more on flat ground and dont tow, I would say keep the 3.90's since its a higher gear and your mileage will be better seeing you arnt turning the motor as fast. I jumped about 400-700 rpm's now on the street. I will see after a few tankfuls how my mileage will be.

 

I am not sure what gears I have but I put on 285/75-16 SSR's which measure bigger than a 33, But it sucks for gas milleage. I used to get about 300 to a tank mostly highway and when I put these tires on I got just over 200 (7% difference in milleage) miles to the tank. I am going to the beach today so maybe ill get better.

Power wise it is not bad, Ill regear when I go to 35s and a SAS. Itll still move but its no V8...

I would just put the tires on and if you don't like it the regear later down the road or S/C it later. But for the mean time if your tring to get by then it will work fine.

EDIT: I forgot you have a 5sp. Youll be fine. Id do it

 

I was going to say that I have a 98 SR5 5-speed and I'm pretty sure when I looked up the gears it has 3.90s

 

I have 285's with 4.10's. It's not a race car, but power is decent and mpg's stay around 17-19 if I keep my foot out of it. You'll have a little less power, but mileage should be better. Since it's only temporary and you're going to regear soon, you should be fine.

 

Remember also, Your mileage figures will be off too since your speedo is off. It will be running slower so it wont read as much mileage therefor giving you inaccurate mpg figures

 

Assuming your stock tire was 265/70/16, your net mpg change is zero. If you are seeing a 7% reduction, you are see exactly what your tire change made your speedo and odo off. Go to http://www.miata.net/garage/tirecalc.html and put in the stock tire and the new tire to see the difference.

I'm on 35's running 4.56 gears with the 3.4. My speedo and odo are 10% slow. With those gears and running 55 down the freeway I'm getting 19-20mpgs.

 

thank you everyone your all alot of great help.

if i got 300 miles out of my tank that would be the best mpg i got EVER. i get alittle bit over 215 to the tank . how much does that SUCK

 

i have 285's on my 99 4runner and the power is fine. now gas milage sucks i get just about 200 miles to a tank when driving slow and stayin out of it. now gettin on it i get about 170 mile per tank. but power you will be fine.