I'm curious as to how much each component of the Civic Hybrid contribute to its fuel efficiency.

Would any of you technically/engineering inclined know, for example, how the low rolling tires help with fuel efficiency(percentage wise or mileage wise)? Or how about the flat aerodynamic rims? Autostop?

Remy,

LRR tires account for 3-5% MPG improvement over standard tires but some tires can be much worse. In all cases increasing the PSI (stay below the MAX cold rating on your tire sidewall) will improve both MPG (a little) and Handling (especially if your tires have soft sidewalls) at the cost of a somewhat harsher ride.

Flat aerodynamic rims are for pretty. They will have an unmeasurable MPG effect.

Autostop can have a big effect on MPG when in stop and go traffic --- up to 20% but has no impact on highway MPG.

The biggest component in MPG savings is that a hybrid can get by with a smaller engine (less internal engine losses) since the electric motor helps acceleration and much of the electrical energy for this help is derived from regenerative braking which recovers energy that would have been lost (in the form of heat) when slowing down.

JeffD

The rims must have some effect, because I don't see Honda designing horrifically ugly wheels for no reason. My opinion, of course, but one that seems to be shared by many (most?).

The wheels may be ugly but they pretty clearly mark you as a semi green driver I'll admit to a small sense of satisfaction whenever a civic pauses while overtaking me on the highway!

As for components If your like me and don't have the factory XM or Navi but an aftermarket, remove the rear XM stub? One its kinda corolla-ish ugly and Two it might cause slight drag? I don't get why honda didn't give us the much better looking body color molded bump normal XM civics and Accords have.

I like the rims.

What I hate is the horn.
Too wimpy.

Need fewer troops to support.
Drive a hybrid.
Best tank 71.65 MPG.

Before this car I spent two years learning hypermiling on my 2004 HCH1.

Speaking of the horn, I almost got run over by a dump-truck sized vehicle within 2 weeks of having my HCH! I just remembered this (I had tried to block it out of my mind).

I was driving on the dreaded Rte 141 in Delaware, just about 1 mile from the I95 exit. Someone in the left lane, sitting in line for the exit decided they didn't want to sit where they were and started coming over into MY lane. I hit the horn a couple times, and to no avail, so I laid on it hard. I barely heard it myself! Luckily, they heard the wimply lil thing and stopped before I got sqashed by them.

Sadly, all I could think of was how upset I'd be that I lost my new car within 2 weeks of getting it to a big truck. Apparently the very good possibility of me getting severely injured never crossed my mind

Yah. The factory horn is dangerous. I installed a Hella Supertone and it's great. It's easy to install too.

For me, two of the top FE components are the FE bar graph and trip/tank FE meters. The feedback helps me a lot to see what FE mistakes I have been making.

I like the rims - they should help at about 100mph

I drive the speed limit and dont peel away at lights so I dont have to honk the horn very often.

Lifetime averages range from 20 to 66 MPG in our database.

That makes the driver the most important component affecting mileage.

Need fewer troops to support.
Drive a hybrid.
Best tank 71.65 MPG.

Before this car I spent two years learning hypermiling on my 2004 HCH1.

I think the Civic Hybrid pie plates are awesome! Futuristic, Space Age and makes all Civic Hybrids easy to identify.

Horn... Come on Honda thats not a horn.