MPG after wheel/tire swap

[dang10010]

I recently swapped a set of escort zx2 wheels and a set of used Michelin tires 195 60 15. My mpg has improved from about 26 to 31. The 5.5" escort wheel the tire is skinnier than a stock 6" which makes the tires closer to 185. Also, I have inflated the tires to 44 psi. I have not driven the car any different and I can say the car coasts much longer now.

[mikeinaus]

what are you getting at? of course a skinnier tires and more psi will increase mileage. rim weight has an effect aswell. i dont know what you had before or how much the escort rims are but our stock rims are fairly light. 12lbs i believe.

[RobMinhas]

what are you getting at? of course a skinnier tires and more psi will increase mileage. rim weight has an effect aswell. i dont know what you had before or how much the escort rims are but our stock rims are fairly light. 12lbs i believe.

I think he's just wanting to let everyone know that fuel mileage is better with skinnier tires and higher PSI. I'm not too sure either actually.

And just so theres someone else to mock in this thread, I didn't know skinnier tires effected mileage..... And I didn't know how PSI changed the mileage much at all, just that stock PSI was always the best.

I'm off to google!

[Evo_Spec]

And just so theres someone else to mock in this thread, I didn't know skinnier tires effected mileage..... And I didn't know how PSI changed the mileage much at all, just that stock PSI was always the best.

having skinnier tires means less contact to the road, same with higher PSI which makes the tread "bubble" out more in the middle which can cause uneven wear.
Technically there's no right/wrong PSI, it's all depending on what your trying to do. Generally speaking if you want more traction you want less PSI and better mileage you want more PSI.

I learnt what the difference PSI's can make on my bicycle =D

[RobMinhas]

having skinnier tires means less contact to the road, same with higher PSI which makes the tread "bubble" out more in the middle which can cause uneven wear.
Technically there's no right/wrong PSI, it's all depending on what your trying to do. Generally speaking if you want more traction you want less PSI and better mileage you want more PSI.

I learnt what the difference PSI's can make on my bicycle =D

Ahh I see, I'm running 32 PSI because thats what the inside of my door tells me to hahah

[dang10010]

The escort rims are 18lbs according to online sources. My old 215 45 17 were much wider and apparently heavier. Another factor is the weight tires as well as the wheels. Wish I had about $800 for some light weight aftermarket rims.
And yes my point WAS skinnier tires inflated to a higher psi will give you better mileage. I plan on having an alignment soon and I will monitor my tire wear, if it wears to much in the middle from over inflation then I will lower the psi.

[MrMazda92]

High PSI FTW

I run relatively high pressure in my tires, as do a few other members here, all of which get good economy from what they say. I've bumped up to over 33 mpg in the city as a record now, with a K8. I'm hoping to keep 27+ when I get my KL in...

[Josh]

Also a harder compound tire will give you better mileage. But over inflation is just as bad as under inflation. You loose a lot of handling and controll. I would stick to the reccomended psi. General rule of thumb run 5 - 10 psi more in the front vs the rear. Due to the weight of the engine.

The skinny tires would be good for winter wheels.

[mikeinaus]

And just so theres someone else to mock in this thread, I didn't know skinnier tires effected mileage..... And I didn't know how PSI changed the mileage much at all, just that stock PSI was always the best.

having skinnier tires means less contact to the road, same with higher PSI which makes the tread "bubble" out more in the middle which can cause uneven wear.
Technically there's no right/wrong PSI, it's all depending on what your trying to do. Generally speaking if you want more traction you want less PSI and better mileage you want more PSI.

I learnt what the difference PSI's can make on my bicycle =D

its less that higher psi makes the center of the tires bubble out and have less contact with the road, but more that they make the tire more round and deflect less to have less resistance. a flat tire has a D shape when sitting on the ground. for it to roll it has to deflect the tire as it turns and there is a large amount of resistance. stock psi has the same effect its just less noticeable, its also affected by rotational force causing the tire to expand at higher speeds. making the tire harder minimizes this effect. for the best mileage possible you would want solid tires on a very smooth surface.

[fowljesse]

Yes. There is a Freight Train company that boasts that they can move so many tons of freight for a mile on 1 gallon of gas, or something like that. You've seen how skinny train wheels are, and metal on metal makes relatively no resistance. I've always dreamed of putting small aluminum train wheels on my car, and going 150+ on good straight train tracks. My next project car is going to be a Metro that gets as close to 100mpg as possible. It will have very tall, skinny, hard tires. I saw a VW Rabbit truck Diesel with significant aero mods, and tall, skinny tires that said "80mpg" on the side.
However, as stated; the less rolling resistance, the less grip, and handling/ stopping power you will have.
I am toying with the idea of having 215 wide tires on the front, and 205, or less on the back, since we have oversteer.

[mikeinaus]

you should look into these tires Jesse i dont think they are going to be released anytime soon but are supposed to be the next major advance in wheels. they use no air, can be tuned for stiffness and seem to me like they could be made to have very little rolling resistance while offering a semi comfortable ride.

[fowljesse]

Weird. Reminds me of this:


It's a trike I built for a Burning Man campmate. if you look close, you can see that I laced a larger rim into a smaller one for the front wheel.

[Josh]

That's pretty cool Must have been a pain to get it straight.

[fowljesse]

It actually wasn't bad, Josh. I used to be a wheelsmith at a bike shop.

[Nd4SpdSe]

I am toying with the idea of having 215 wide tires on the front, and 205, or less on the back, since we have oversteer.

Ya, my next set of tires I was going to try that setup. Got the idea from the Pontiac GXP