something that came to mind the other day... i've been curious why my gas mileage has gone down since i put on my kuhmo 225-55-16's and i think i may have an answer. due to the increased dia., i am not registering as many wheel revolutions per mile. i forgot the exact amount of revs. for the 225-55-16 compared to the 215-55's, but i know @ 80mph, i was going atleast 5mph faster compared to two other maximas set @ 80mph. so do you thing over a course of 300-400 miles, could the mileage be off by 2-3 mpg due to the fewer amount of revs. per mile? i'm going to try to work out the math when i have more time, but does this make sense to anyone else?

-jon

 

Hey,

I know that when I put oversized(225 50 16zr) tires on my stock 16s my acceleration suffered a noticeble amount. It might be because the new tires are heavier or maybe due to you theory.

Just my $0.02.

Peace.

 

makes sense. you have to rotate the wheel further to achieve the same ammount of travel, so it would sensically give lower MPG. check your tire pressure, too!

 

tire pressure is fine... i keep it kinda high actually... 38-40psi

 

actually, going from the stock 215-55 16 to a 225-50 16 will make your diameter smaller, this should actually increase your acceleration because it acts like raises the gearing of the car, because of the slightly wider tires, and because you have stickier rubber now. In no way should this decrease your accelaration, or are you just thinking it does because you can't spin them as much anymore?

 

I felt the decrease in acceleration. I think the reason for that is because the new tires are heavier than the old tires. Now this makes me think hard about buying 17in wheels. After the 17s I'll need a y-pipe just to be back at stock acceleration

Peace.

 

Your new tires are wider, so they cause more aero drag. Also, because they are wider, they stick better, causing more road friction. They are also heavier, so your motor has to work a wee bit harder to turn them around. All these factors will impact your mileage in a worse way.

DW

 

i don't know if that reply was to me or not, but actually the tires i had previous to my kuhmo's were 225-50-16's... smaller diameter... but wider... and softer. but i was getting 24mpg city and up to 30mpg highway. now i'm lucky to get 20 city and 25-26 highway. so i don't think the width had much to do with it... but possibly the weight... i know the kuhmo's are bricks compared to the bridgestone RE-930's i had. but i'm in the market for tires again... either going back to stock.. or a 225-50 tire... i'll let everyone know if my gas mileage changes at all.

 

I thought the comparison was 215s to 225s. Oh well.

DW