Bad Gas Mileage Due To Tires??????
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Joined: Nov 2004
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Bad Gas Mileage Due To Tires??????
Here's the deal. I replaced the factory rims and tires on my 2003 Neon SXT (15" Aluminum 7 Spoke, 185/60R15), with 17" Sport Edition Fox 2 rims, and 205/40YR17 BFGoodrich G-Force T/A KDW2 tires. Before I replaced the rims and tires, I was getting around 35 MPG on the highway, and 30 MPG in the city. I didn't notice a big difference after I changed them, but gradually over time, I have been getting worse gas mileage. The tires now have around 14,000 miles on them and I'm getting around 23 MPG on the highway, and 18 MPG in the city. Does anyone know if this is a tire issue? I know these tires have a really soft compound and I have been keeping tabs on the air pressure and the air pressure is fine. Should I go back to the factory 15" rims, or do you guys/gals think that changing to a different tire will fix the problem. One of my friends told me that he thinks it's just due to the fact that the tires I have right now are really soft. He thinks that if I go with a harder compound, it may fix the gas mileage issue. What do you all think?
FYI.....I have also changed spark plugs, spark plug wires, and coil. Still get the same gas mileage. I also had my car tested at a Dodge dealership, and they couldn't find anything wrong. They just stated that I had the wrong size rims/tires on my car.
Any info would greatly be appreciated.
FYI.....I have also changed spark plugs, spark plug wires, and coil. Still get the same gas mileage. I also had my car tested at a Dodge dealership, and they couldn't find anything wrong. They just stated that I had the wrong size rims/tires on my car.
Any info would greatly be appreciated.
Thread Starter
Joined: Nov 2004
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RE: Bad Gas Mileage Due To Tires??????
ORIGINAL: TJW815
check your alignment, toe, all that good stuff.... Or have a tire shop do it
check your alignment, toe, all that good stuff.... Or have a tire shop do it
I know the tire shop checked my alignment and adjusted it when they put my new rims/tires on. I would think that they would have checked everything else when they did the alignment as well. The tires have even tread wear, and the car drives perfectly straight when you let go of the steering wheel. The biggest difference I have noticed with my current tires, besides the gas mileage, is the fact that they are really loud. I know that is due to the aggressive tread design, but these things really hum whem you get up around 40-45MPH.
I keep the tire pressure around 34 PSI.
Noob Assassin
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RE: Bad Gas Mileage Due To Tires??????
Obviously check all the basic stuff like the other threads have stated.
1.) I noticed that you changed rim size/tire size/tire diameters/tire width....but you didnt adjust your speedometer. Since your car was setup for a 15" wheelsize....since you've changed it....it will not run accordingly....which will reduce MPG......your car is running at a different ride height and also at a faster speed. You may think your speedometer reads 65, but infact you could be doing 70. I suggest you check on this fact ASAP.
2.) Check the information out for your type of tire...some low profile/performance tires require higher psi then normal tires...running at 34psi instead of say 39psi could cause your problem. Some low profile tires require up to 45psi.
3.) Have you tried cleaning your fuel injectors/fuel injection system recently? Your exhaust? There are places that offer those kind of services.... IF those are filthy, or clogged up...this could potentially cause the same issue..
4.) New air filter maybe? Or maybe your having air intake issues?
5.) Bad or failing fuel pump filter?
6.) Tires simply arent up to the quality you need.
The first suggestion I posted is one you need to look into immediately....as this could not only be the cause of your problem...but it could get you a ticket for speeding....even though you might not think you were speeding.....
1.) I noticed that you changed rim size/tire size/tire diameters/tire width....but you didnt adjust your speedometer. Since your car was setup for a 15" wheelsize....since you've changed it....it will not run accordingly....which will reduce MPG......your car is running at a different ride height and also at a faster speed. You may think your speedometer reads 65, but infact you could be doing 70. I suggest you check on this fact ASAP.
2.) Check the information out for your type of tire...some low profile/performance tires require higher psi then normal tires...running at 34psi instead of say 39psi could cause your problem. Some low profile tires require up to 45psi.
3.) Have you tried cleaning your fuel injectors/fuel injection system recently? Your exhaust? There are places that offer those kind of services.... IF those are filthy, or clogged up...this could potentially cause the same issue..
4.) New air filter maybe? Or maybe your having air intake issues?
5.) Bad or failing fuel pump filter?
6.) Tires simply arent up to the quality you need.
The first suggestion I posted is one you need to look into immediately....as this could not only be the cause of your problem...but it could get you a ticket for speeding....even though you might not think you were speeding.....
Thread Starter
Joined: Nov 2004
Posts: 28
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RE: Bad Gas Mileage Due To Tires??????
ORIGINAL: DevilsReject
Obviously check all the basic stuff like the other threads have stated.
1.) I noticed that you changed rim size/tire size/tire diameters/tire width....but you didnt adjust your speedometer. Since your car was setup for a 15" wheelsize....since you've changed it....it will not run accordingly....which will reduce MPG......your car is running at a different ride height and also at a faster speed. You may think your speedometer reads 65, but infact you could be doing 70. I suggest you check on this fact ASAP.
2.) Check the information out for your type of tire...some low profile/performance tires require higher psi then normal tires...running at 34psi instead of say 39psi could cause your problem. Some low profile tires require up to 45psi.
3.) Have you tried cleaning your fuel injectors/fuel injection system recently? Your exhaust? There are places that offer those kind of services.... IF those are filthy, or clogged up...this could potentially cause the same issue..
4.) New air filter maybe? Or maybe your having air intake issues?
5.) Bad or failing fuel pump filter?
6.) Tires simply arent up to the quality you need.
The first suggestion I posted is one you need to look into immediately....as this could not only be the cause of your problem...but it could get you a ticket for speeding....even though you might not think you were speeding.....
Obviously check all the basic stuff like the other threads have stated.
1.) I noticed that you changed rim size/tire size/tire diameters/tire width....but you didnt adjust your speedometer. Since your car was setup for a 15" wheelsize....since you've changed it....it will not run accordingly....which will reduce MPG......your car is running at a different ride height and also at a faster speed. You may think your speedometer reads 65, but infact you could be doing 70. I suggest you check on this fact ASAP.
2.) Check the information out for your type of tire...some low profile/performance tires require higher psi then normal tires...running at 34psi instead of say 39psi could cause your problem. Some low profile tires require up to 45psi.
3.) Have you tried cleaning your fuel injectors/fuel injection system recently? Your exhaust? There are places that offer those kind of services.... IF those are filthy, or clogged up...this could potentially cause the same issue..
4.) New air filter maybe? Or maybe your having air intake issues?
5.) Bad or failing fuel pump filter?
6.) Tires simply arent up to the quality you need.
The first suggestion I posted is one you need to look into immediately....as this could not only be the cause of your problem...but it could get you a ticket for speeding....even though you might not think you were speeding.....
I have checked my speedometer, and when I'm doing 65 MPH it's only off by 1 MPH. The factory tires have 880 RPM (Revolutions Per Mile) and the tires I have on there now have 885 RPM.
I'll have to check the tire pressure range for that tire. I know the Max PSI is 50.
The fuel injectors are clean...used Lucas Oil treatment for that. Also, I don't have any hesitation at all. I have a K&N Air Filter, and I just cleaned it.
Here's the realy catch. I just took my car to the tire shop and got it back. They said that the rear alignment was way out of wack. They had to install a camber bolt in the left rear (since the 2003 Neon doesn't have rear camber bolts) to adjust the camber. They said the Toe was way off as well on both sides. I told them that they were supposed to do a full 4 wheel alignment when I had my rims installed a year ago, but they said they only did a front end alignment.....I'm not sure if that would cause that big of a gas mileage loss or not....guess I'll find out in a few days.
Let me know what you think.
Noob Assassin
Joined: Jul 2005
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RE: Bad Gas Mileage Due To Tires??????
If your alignment was that off....it would have a HUGE effect on the gas mileage. Sounds like they screwed you originally. They only aligned your front wheels because its front wheel drive.
Most tires are recommended to run at 33-37psi. However, some brands/sizes are required to run slightly higher. For example....most tires max at 50-55psi. Some will recommend you run at 40-45psi. I would contact the tire company or the place you bought them from and ask about it.
Glad to see you did your homework on your car, and that you take care of it! Neons a good car
Most tires are recommended to run at 33-37psi. However, some brands/sizes are required to run slightly higher. For example....most tires max at 50-55psi. Some will recommend you run at 40-45psi. I would contact the tire company or the place you bought them from and ask about it.
Glad to see you did your homework on your car, and that you take care of it! Neons a good car
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Thread Starter
Joined: Nov 2004
Posts: 28
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RE: Bad Gas Mileage Due To Tires??????
Yeah...I try to find out as much as I can about my car. I really enjoy it and it's been a great car. As for the tire pressure, I contacted Tirerack.com (place where I bought the rims/tires), and they said to go by the car manufacturers recommended tire pressure...even though it's a lower profile tire. I didn't want to argue with him, but I don't see how you can make a drastic change in tire size and you wouldn't have to adjust the tire pressure accordingly. The factory tires say they should have a max PSI of 44. That's 6 PSI lower than the max on the KDW2's. I'm wondering if I should bump up the PSI around 38-40. I might also contact BFGoodrich to find out what they say.
The real test will be when I drive cross-country again....I'm moving back to California from Indiana.
The real test will be when I drive cross-country again....I'm moving back to California from Indiana.
Thread Starter
Joined: Nov 2004
Posts: 28
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RE: Bad Gas Mileage Due To Tires??????
Called BFGoodrich and they told me that I should be using 40 PSI. So I went out and now all my tires are at 40 PSI. Find out how all of these changes work out by this time next week.