Celica Forums General Discussion General Convince Me That I'm Wrong About My Gas Mileage

Ok guys I've read some posts that stock rims actually help your gas mileage compared to the larger rims. I'm somewhat thinking the opposite and I'm just wondering, have I gone crazy or does it make sense.

Basically when I drive, I never past 3k. I shift at 3k or below. Maybe once or twice I'll take it up to redline for 1 gear.

My thing is the gas mileage in the 2002 gts. I'm only getting around 325 miles using about 12 out of the 14.5 gallons. This doesn't seem right to me unless I'm just crazy. I have on 18's right now and was thinking, if I go back to the stock 16's it'll improve the gas mileage a bit.

During the week I rarely ever hit traffic, I drive home when there is minimal traffic to no traffic at all. As for city driving, i usually drive stop and go for around 10 miles a day.

My question is, isn't it better to have the 18's on if I'm never in traffic and all the miles are freeway miles? My hypothesis is that lighter tires will be better for stop and go since it will take less amount of force to get the tires moving from a stop and go. And it would be better for freway with the 18's because it's in motion. When thinking about the physics, wouldn't a heavier object already in motion take less force to move it since it would have more momentum opposed to a lighter tire? Tell me I'm crazy and that the lighter tires will improve gas mileage and be better

hmm. small rims are better. it takes less power to have it, how do you say, move the car. smaller diameter requires less energy to move the car. but then again, if this is a major concern for you, your best bet is to return to stock.

and you're crazy

i'm just using an example. Say you were to drop a pebble and a boulder at the same time from the top of the building, the boulder would fall faster until they both reach terminal velocity which I forgot what it was, i think 9.8 m/s. But neway that's why I'm thinking larger rims would be better for freeway. Since there would be a greater momentum force therefore using less enegery to turn the wheel each revolution.

And yes i think i'm going crazy because I'm analyzing this so much

wow. i dont know anymore

http://ks.essortment.com/waystoimprove_rryi.htm

Might provide some insight in to your question I guess...

after reading that, my question still unanswered. I see all the logic behind that article but yet I just want an answer to my question with a good explanation why I'm crazy for even thinking that. I know that there's other factors involved, but I'm doing this from just the standpoint of the rims.

You were way off about that terminal velocity thing. Terminal velocity is the maximum achievable velocity of a falling object and is directly related to its mass. 9.8m/s is the gravitational acceleration placed on an object in the Earth's atmosphere. Thus, when you drop an object, its acceleration rate is 9.8m/s. Weight is measure in a similar fashion: mass * gravitational acceleration = weight. Hence why things weigh differently on other planets, but retain the same [n]mass[/b]. In your example, the boulder would accelerate at the same rate as the pebble, however it would eventually reach a higher speed. The small pebble would not go as fast, thus why a penny dropped off the Sears Tower won't actually kill anyone. Also, you can drop an ant off the building and it would live, assuming you were able to find it afterwards.

i knew 9.8 m/s didn't seem right thank you for the physics refresher...it's been 1 year and a lot of forgotten things

Ok, so does anyone have an explanation for my theory aside from the boulder/pebble example?

Well, heavier rims mean your engine has to work harder than stock to run at certain speeds. It may not feel like it is, but it is. Think about pulling a wagon. Then add about 2 pounds to it. You wont realize it, but it does require more work to pull. It makes little difference then and there, but as time goes on, you'll start to notice. Same deal with your car. The heavier rims will require more gas in the long run theoretically, but the weight difference is so negligable that there are many other effects on gas mileage that will likely cause the difference.

Taken from http://www.daveblack.net/asp/TirePlusSizing.asp

This is begining to feel like one of the problems that seems as if there are really no definite answers.

I get bout 27-30mpg and I keep my car between 3 and 4k.

i get about 300 mile for a full gas of tank on street and about 330 on highway..

i guess the only real way for find out is get my lazy butt up and switch out the rims, fill up the tank, and see what really does happen

the example i should've used was something along the lines of joules.

I get over 400 on stock rims, I have a long comute of open road though, and I shift between 3k and 4k.

imma switch it out this weekend and give it a test run. I'll post up the result in about a week for those who care

I get around 400 miles per tank (thats around 32-33 mpg) with my '04 GTS with stock rims. My driving is mostly highway. I don't think there is much connection to rims/mileage, but I could be wrong. If you've still got stock rims and tires sitting around, it would be great to compare. My suspicion is something else is cutting into your mileage a little, like maybe some sort of fuel injection problem, or something with the plug/plug wires. I'd run some cleaner through the injectors and maybe take it to a shop for an engine analysis. Or it could just be the driving conditions there in Hawaii. Whatever you do, please post back what you find out, and good luck!

Larger rims and tires equals larger rotational mass. Requires more energy to turn.

If you do get larger rims try to get lighter weight of course and smaller tread on the tire. Like a 205/xx/xx