View Full Version : tire size affect on MPG and acceleration?


stankubrick
10-11-2003, 09:20 AM
Bear with me,

(I had to edit this...too confusing even for myself!)

I'm new to the whole wheel and tire thing so I'm a bit confused. Let's see if I have this right (as there are many variables, I'm sure there's no perfect answer):

Basically, I can't decide between 17" 16" or 15" rims and I can't decide how wide to go (205-225).

First off all, does tire width (i.e. 185 vs 225) affect MPG? acceleration?

Secondly, If I go 5% or more larger than stock diameter (for a cushier ride on lhigher sidewalls) how will that affect MPG? Will it be slower? How about if the diameter was smaller than stock? faster?

I wanna put comfort, speed and mpg before looks (soundling like gramps...and I'm only 25)

Hope this is not too trivial....any advice would be appreciated...

toybox1
10-11-2003, 02:11 PM
the tires size (diam/width) won't affect your MPG noticably since your not changing the rolling distance much ... even over stock (the idea is to pick a rim/tire combo within +2 sizing)

however the wider the tire the more contact area ... this means handling and acceleration will change

I'm rollin 18's (w/ strut bar) and noticed a HUGE difference in handling. I can take 15mph turns at 40 and it's like it's on rails. However, the ride is sacraficed some (little harsher ride and grooves in the road tend to pull it)

scionspecialistvegas
10-11-2003, 02:43 PM
I agree, that different size tire should not adversely affect gas milage. My short bus rolls on 17" konig meshes with 205\40\17. It does handle alot better and ride is not to harsh. I average 27 to 30 mpg with an automatic, depending on how much I use the aircon.

I have notice more torque steer since I put conti's on. I have had directional tires on mini trucks but nothing hug the roads like these 17\40.

Imight the first scion in Mexico. I am taking wife to meet some of high schol buds in southern arizona and nothern mexico. The told me that have micro van\miniwagons there also. hould be fun. This also the real test of my alarm system. If I drive it home, I should market it.

sensez
10-11-2003, 04:51 PM
lasvegas:

what kind of tires you runnin?

scionaraxb
10-11-2003, 05:08 PM
I have to disagree with some of theses posts. If you go 5% bigger in diameter, the engine will have to work harder to achieve the acceleration most of us expect in a car. That goes for starting from a stop to passing on the freeway, you will be pushing down harder and longer on the gas to get both of these done. These engines are pretty weak in the torque dept. so it takes rpm to get them moving, to get the same rpm with bigger diameter tires will take longer and cost more fuel.

scionspecialistvegas
10-12-2003, 01:25 AM
I am rolling continental conti extreme extreme contact. I got the guys at discount to price match wheel max. They gave a complete package including lug nuts and life time warrantee for 700 hundred then they gave $100 trade in for my stock skins. I'll post some pics from mexico in acouple of weeks when we get back.

Torokun
10-12-2003, 08:21 AM
I have to disagree with some of theses posts. If you go 5% bigger in diameter, the engine will have to work harder to achieve the acceleration most of us expect in a car.

By theory it should, right? But, in real life, it doesn't effect that much... having a slight higher side wall than the stock diameter doesn't even effect the speedometer. Why? i dunno... I wish I knew...

toybox1
10-16-2003, 10:47 AM
scionaraxb - you are correct ... going too big (or small) will have a noticable affect, which is why you want to stay within +2 sizing. In that range all you are doing is replacing tire with rim ... no real increase in rolling diameter.

It's the rolling diameter (and width) that will change performance aspects such as acceleration.

stankubrick
10-16-2003, 11:38 AM
I found this page while surfing for tire info. It pretty much answered all my questions......plus its geared towards our interest

http://www.leecao.com/honda/wheelstires/

peace