When I bought my 07 TCH back in Aug 06, the 16" alloy wheels were standard. I was getting about 35mpg on those wheels with the stock Michelin tires. I drove on those tires for 5k miles, so I got a very good average on my fuel efficiency. Then as many of you know, I upgraded to 18" Lexus GS wheels with BFG tires, as well as lowered my car. My FE stayed about the same, it was usually around 34.5 - 35 with that setup. I paid for those Lexus wheels by selling my 16" stock wheels, but I kept the Michelin tires in the garage. Well, 40k miles later, those 18" tires are bald, so rather than buy new 18" tires, I found a great deal to buy four Camry 16" steel OEM wheels for just $80. So I mounted my original Michelin tires on these steel wheels, and lo-and-behold I've been averaging 37mpg so far over three full tanks of gas. My commute has not changed, nor have my driving habits, I have not been trying to maximize FE anymore than i usually do.

This makes absolutely no sense to me. Why would lighter alloy wheels have worse fuel efficiency than heavier steel wheels? The only thing I didn't do is I didn't transfer the TPMS sensors into the steel wheels, but I can't believe that the TPMS would weight that much to cause a 2-3mpg impact. Has anybody else out there traded between the OEM 16" alloy wheels and the OEM 16" steel wheels (and hopefully used the same tires on both) and noticed the same thing as I have?

With today's gas prices, I'm going to completely use up these 16" Michelins before I buy my next set of 18" since they are getting me an improved FE.

CAMRHEE Hybrid - FOR SALE!!!!
Completed Mods: RK-Sport body kit, 18" LexusGS430 wheels 235/50ZR18 tires, TRD/SE springs, Rear Lip Spoiler, Terk XM-Direct, Smoked tail lights, Sliding Armrest, Rear Bumper Applique, Front License Bracket, Lower Grill chrome inserts, K&N, Blaupunkt THB200A sub, moved rear HSD emblem
Future Mods: fog lights, black chrome my wheels

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Very strange indeed. Perhaps the TCH wasn't yet broken in when you switched to the 18s, and now, with over 40K miles, it is broken in, yielding better fuel mileage? The true test would be to get some TCH alloys and your 16 inch Michelins, but that would be a pricey test....

Also, is there a differene in your gas, summer blend vs winter blend???

edit: Additionally, aren't the alloys part of an optional package now on TCHs? I wonder if the mileage diff between the alloys and steel wheels is even noticable?? Certainly there isn't a different EPA rating which is dependant on which wheels the car has.

Do you know the weight of the 16" alloy wheels?

2008 Barcelona Red TCH Mods: 20% hybrid window tint, Wade window vent visors, lower grill chrome accents, fog lights, factory spoiler, Razzi ground effects, Razzi simulated dual exhaust

I thought about the break-in factor, but I looked at my spreadsheet since I've tracked every tank of gas since I drove off the lot (all 106 of them ) and the mileage has been very consistent. And you are correct, the steel wheels are now standard equipment and the alloys are an option you need to pay for (which is how I got the steel wheels so cheap, because that person was upgrading to aftermarket alloys).

Great question that I asked myself but couldn't find the answer. My service spec sheet on the wheels has all kinds of details but doesn't say the weight. I am making a big assumption that the 16" steel wheels are heavier than the 16" alloy wheels.

CAMRHEE Hybrid - FOR SALE!!!!
Completed Mods: RK-Sport body kit, 18" LexusGS430 wheels 235/50ZR18 tires, TRD/SE springs, Rear Lip Spoiler, Terk XM-Direct, Smoked tail lights, Sliding Armrest, Rear Bumper Applique, Front License Bracket, Lower Grill chrome inserts, K&N, Blaupunkt THB200A sub, moved rear HSD emblem
Future Mods: fog lights, black chrome my wheels

http://www.greenhybrid.com/share/fil...fterFront4.JPG

1) The michelin tires probably have a lower rolling resistance factor than the BFG.
2) The circumference of the 18 inch tires is greater than the circumference of the 16 inch tires. Without recalibrating your odometer, you were going a further distance per tire revolution with the 18 inch tires than the 16 inch tires. Perhaps the added distance negated the increased weight of the wheels; or at best, is not too discernable a difference.

Mods: Surveillance Front and Rear Cameras for Realtime Display and Recording

I'm sure the answer is your Michelins are a Low Rolling Resistance tire, and the BFG's are not.

Flopshot,

Would you mind posting pictures of the new setup? I am wondering what 16in wheels look like with your lowered TCH. I am considering going with aftermarket wheels because I find the stock rims to be a bit bland, but don't want to give up my brand new tires (i.e 16inch) at the same time.

Thanks.

Ron

You have both completely missed the point of my original post. Forget about the 18" wheels or the BFG tires, I mentioned them strictly for comparison to say that particular setup had negligible difference to my original 16" OEM alloy wheels with Michelin tires, but it really has no relevance to the question I am asking. The bottom line is that I took the stock Michelin tires off of my 16" OEM alloy wheels and put them on 16" OEM steel wheels (minus the TPMS sensors), and my fuel mileage increased by 2.5-3mpg.

CAMRHEE Hybrid - FOR SALE!!!!
Completed Mods: RK-Sport body kit, 18" LexusGS430 wheels 235/50ZR18 tires, TRD/SE springs, Rear Lip Spoiler, Terk XM-Direct, Smoked tail lights, Sliding Armrest, Rear Bumper Applique, Front License Bracket, Lower Grill chrome inserts, K&N, Blaupunkt THB200A sub, moved rear HSD emblem
Future Mods: fog lights, black chrome my wheels

http://www.greenhybrid.com/share/fil...fterFront4.JPG

Look at other factors - the environment - the weather has gotten warmer so there is a shorter time to get the ICE up to operating temperature which in turn uses less gas at cold startups.

Mods: Surveillance Front and Rear Cameras for Realtime Display and Recording

Never mind... you obviously are not reading my whole post and you're just responding to random sentences that you read. I bought my car in Aug 2006 and put over 5k miles on it before I switched out the stock 16" alloy wheels, and I've got 100+ tanks of gas and 50K miles overall, so I think I know my car's averages pretty well.

Looking for any other informed opinions...

CAMRHEE Hybrid - FOR SALE!!!!
Completed Mods: RK-Sport body kit, 18" LexusGS430 wheels 235/50ZR18 tires, TRD/SE springs, Rear Lip Spoiler, Terk XM-Direct, Smoked tail lights, Sliding Armrest, Rear Bumper Applique, Front License Bracket, Lower Grill chrome inserts, K&N, Blaupunkt THB200A sub, moved rear HSD emblem
Future Mods: fog lights, black chrome my wheels

http://www.greenhybrid.com/share/fil...fterFront4.JPG