riceball777

I bought my 2006 civic hybrid with the civic ex wheels on the car with stock size 205/55/16 non lrr tires. The seller also gave me the stock 15 inch hybrid wheels with stock size 195/65/15 tires that are also not lrr tires. I have put 15,000miles on my civic hybrid with the stock 16's and I average 40mpg. I have never driven on the stock hybrid 15 inch rims.

I just baught some light weight volks le37k 17x7.5 +40. I bought new 205/50/17 low rolling resistant contenental pure contacts tires. I have put 3,000 miles on this new setup and I'm geting 34-36 mpg. How the hell did I loose 5mpg going to a rim/tire combo that weights 5 pounds less plus I'm now rolling on lrr tires for the first time!!!

The stock 16's with tires weigh 40 pounds and 6oz. The stock hybrid rims and tires weigh 34 pounds and 7oz. My volks with lrr tires weigh 35 pounds and 5oz.

How the hell did I loose 5mpg going from the 16's which weigh 5 pounds more to my 17 inch volks also with lrr tires.

Some one make sense of this for me.

Tonight I just took my volks off and put the stock 15 inch hybrid rims on for the first time ever. Let's see what mph I get with the stock hybrid rims which don't even have lrr tires.

OneBadTurboCRV

Screw the loss, why in the hell does your hybrid get such shitty gas mileage to begin with? My '13 Si averages around 34 mpg mixed and I have gotten over 39 mpg taking it easy mixed driving. I have seen as high as 48 mpg hypermiling style highway driving.

Are you positive nothing else is going on with your car? Like the batteries are taking a crap or the engine is running rough? Are you sure your tire pressure is nominal?

grumblemarc

iTrader: (4)

Wind resistance?

DaveSi677

Also you got the wrong tires size which that could also cause a lost... you are 9.34% off you oem diameter.

But so many factor can come into play. How much air psi do you have in your tires? If you car dirty or clean? The tire compound also... we can go on about it really.

riceball777

You are in correct. This car is suppose to run a 25 inch diameter tire. The stock size is a 195/65/15 which is 25 inch in diameter. I'm now running 205/50/17 which is 25.1 inch in diameter. The stock 16 inch size is 205/55/16 which is 24.9 inches in diameter.

With the volks I am running the correct size to maintain the same diameter and to keep the speedo as accurate as possible.

riceball777

There is nothing wrong with my hybrid. I don't do hyper milling. I just drive normal. I use to have an si and I average 24mpg in a si. The millage you speak of in an si is not realistic.

Samuraij

I was going to think maybe it had something to do with the centrifugal/centripetal force your wheels are generating but what Dave says makes a lot more sense than what I was thinking.

OneBadTurboCRV

Mmmkkkkaaaayyyy... whatever you say. Either you can't drive very well or you don't know what fuel economy means.

DaveSi677

No matter how small the difference is it will make a difference that is has a huge impact or not... might not be that drastic of a change but it add a small sum to your issue but obviously it's not your main problem...

Again like I said you have a million variables here to look at! I can't believe that Volks wheel would make you get worst gas mileage. That is as stupid as saying Hondata Flashpro is the reason why your car is having straight line speed instability...

You have a lot of things to look at...

tire pressure?
compound?
air filter?
any damage to your car?
what type of oil are you using?
a bad o2 sensor?
spark plugs are good?
are you using your AC more then the usual?
are you caring more cargo then usual?
your driving habits?

Also every tire is different so it could be that your tire has increase ride height which can play a small factor too...

These are more reasonable reason why you are getting bad gas mileage not because you got a set of Volks wheels...

riceball777

Trust me I can't believe it either

For the first time I'm have been rolling at the stock hybrid 15 inch wheels withe stock size 195/65/15 with cheep non low rolling resistant tires and I millage I can tell is already a huge difference. In the past 2 days with the stock hybrid rims I been getting about 42mpg.

With my new volks with lrr tires. With the volks and tire combo weighing the same if not less than the stock 15 inch hybrid rims. With the volks useing a 205/50/17 which is the same overall diameter as the stock wheels No matter how slow or easy I drive I will never get over 35mpg. Your talking easy 70+ less miles per tank!!!

They say the stock hybrid rims are made to be extremely aerodynamic for the hybrid. I guess this test proves it. I just find it hard to believe that a change in wheel design with out a change in weight or over diameter can affect millage by such a great deal in this car.

DaveSi677

you are also using a wider tires so that takes a little more effort to turn but should be that drastic of a change.

grumblemarc

iTrader: (4)

I figured the stock rims can't have been made that ugly by accident.

lazlong

It shouldn't make any difference with the width of the tire. I've ran up to 225/40/17 on alloy rims on my 2001 and still got well over 30mpg.

Maybe the 8th gens just don't like wider tires.

Wanderer.

The total weight of the wheel and tire package is important, but not as important as WHERE the weight is carried on the wheel and tire.

I am willing to be that though the total weight is lower, the short sidewall tires on the 17s as well as the wider wheel has moved the weight outboard away from center. It takes more effort to move the weight placed far from the hub.

IDK if that makes any sense but hopefully you get my drift.

That and tire compound can play a part... everyone is quick to label their tires as LRR tires these days, what qualifies them as such I do not know, maybe someone can enlighten me.

Seeing as how the tire width has remained the same or similar and total weight is lower, this is all I can come up with.

riceball777

Please read the post. You are incorrect. Im useing the same 205 wide tire with the same over all 25 inch diameter tire.

I have been driving my civic hybrid with the ex rims with 205/55/16 tire and have obtained 40mph average over 15,000 miles.

I went with light weight volks with lrr 205-50-17 tires. This tires and rim combo is the same 205mm in width and the same 25 inch in diameter and weights 5 pounds less. The volks are only able to produce 35mpg at best over the past 3000 miles

For the first time I put the stock hybrid 15 inch rims on and millage has instantly jumped to 42 mpg in the past 2 days.

Crazy...

grumblemarc

iTrader: (4)

Aerodynamics.

tlarimer

iTrader: (3)

Final loaded tire diameter is greater on the larger wheels, since the smaller sidewall doesn't compress as much as the OEM wheels and tires. So while you say stock tire is 25", subtract roughly another 1" for final loaded tire diameter on the stock tires because it has greater sidewall flex. So you need to compare final loaded tire diamter, not unloaded tire diameter.

shotoutacc0rd

They look nice though, save em for the car show?

DaveSi677

You are incorrect in 2 different areas...

1. Not 2 tire manufacture makes the exact tire size the same! A 205 Falken Azenis wasn't the same as a 205 from Toyo. The Azenis was a little larger. Meaning unless you had the exact same tire on all your wheels tire size is an issue.

2. Also what is the stock size for the hybrid? 195 not 205... meaning you are using a wider tire then stock.


Also the compound is different from one tire manufacture to the other. Just cause it's lrr doesn't mean it's the same as another!

OneBadTurboCRV

OP needs to be educated on tires apparently...

www.tirerack.com

Read until your head explodes.

OneBadTurboCRV

Ok, believe what you want. I get 33-34 mpg regularly. It only dips down to 30-31 during the winter time with **** fuel and added warm up cycling. Either I got a magical engine / tune or you guys just can't drive. I even inquired the dealer salesmen (since I go there multiple times a week for parts and to have my POS Si worked on) and they say people report 30-34 combined mpg as well. I thought I was doing good but got deflated at the dealer haha.

It could be I am near sea level with relatively flat roads as well. Many factors go into achieving MPG good or bad. If I use cruise control my MPG drops by almost 3-4 on average. The fly by wire sucks for fuel economy as well. It was just made to help people who absolutely can not drive. I can only hit high 40s mpg driving around 45-55 and relatively flat roads while hypermiling. Don't get me wrong, I have gotten as little as 10 mpg on 1/2 tank from beating the dog **** out of the car and excessive idling (AutoX).

If you have driven the car enough you will find this is one of Hondas worst tunes. The thing lugs severely while cold or at the bottom end of the map. I am very sure there is more fuel economy there in the tune as I have black soot all over my exhaust pipe with under 12k miles. In any event, I can't wait to sell it - I didn't buy it for fuel economy.

Todd00

1) Offset of the new wheels (if they "stick out" more from the body--the hybrid wheels tuck nicely), 2) plus the spoke design (more wind resistance) and 3) flatter contact patch of the tire and more aggressive tire compound will all contribute to less mpg.

And as was said, weight further out from the center of the rotating mass will mean that it takes more effort to accelerate.

Also when comparing two 205 tires, one could have a significantly different contact patch from the other.



Or it could just be those ugly @ss blue lugnuts.