Do I have a lemon HSD?

I recently replaced the OEM tires with Hydroedges. I estimated a 5-10% fuel mileage hit with them originally, some (not all) of which I have probably regained after their breakin. As one who obsesses about fuel economy, the loss has been frustrating at times. But not enough to put Integritys back on; their poor tread life and inferior handling don't justify it, IMHO.

Not sure what else could be at work here, if anything. As you know, there are many variables that affect fuel economy: routes, terrain, weather, driving time, speeds, technique ... as well as the vehicle. Brainstorm a bit and ask yourself what else could be different. The longer runs, for example, could be contributors. Don't underestimate the effect of winds. Even small differences in wind conditions can have a significant impact on FE.

 

Check your oil level. If it was overfilled at the last oil chage, you will also take a mileage hit. It happened to me twice and the reduction was almost 5 MPG. I try to keep mine just below the full mark. However, when dealers replace the oil, you may find the level about 1/4" over the full mark.

 

Well, let's see...

I think we're getting oxygenated gas now in Northern CA, which does drop mileage in the winters, but that's only seasonal.

Things to consider:
*tire pressure
*type of tire and, especially, how heavy it is
*did you replace with the same size, or go up to 195's?
*oil level
*alignment (I've heard this can be a big one)
*short trips really kill mileage in any car, even the Prius

But, gosh, those HydroEdges in the stock size, are only 2lbs heavier, each, than the Integrities (19lbs. vs 17lbs.) That's I guess that's something like 10%, but, still...

I bought bigger, stickier performance tires for my Prius and am discovering that the initial acceleration (like when the stoplight first turns green) isn't quite as brisk, so I'm giving it more gas to get it rolling. I wonder if that's what's going on in your case...?

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Random thought: I wonder if, really, a disproportionate percentage of the Prius' economy advantage is as simple as the fact that it's rather under-tired (especially the non-Touring edition)...?

Put more conventional tires on it, and it's surprising how quickly the excellent mileage begins to erode.

 

<div class='quotetop'>QUOTE(Rufaro @ Oct 29 2007, 06:31 AM) [snapback]531893[/snapback]</div>

 

<div class='quotetop'>QUOTE(Rufaro @ Oct 29 2007, 06:31 AM) [snapback]531893[/snapback]</div>

any tires that "grip" more, lower mpg. physics the more a tire slips the less gas it takes to move the car at speed. your car will handle better and spend more fuel fighting momentum because they grip. also maybe cold weather, short trips and not reseting the consumption screen.

 

<div class='quotetop'>QUOTE(Rufaro @ Oct 29 2007, 04:31 AM) [snapback]531893[/snapback]</div>

It seems as if you drive the rental an average of 25 miles per day as opposed to the 10 a day that you drive your own car. The rental spends considerably fewer miles warming up to operating temperatures. That, and the tires, should account for most of the difference.

 

Hi Rufaro,

Hate to ask this. But did the bodywork require any re-painitng? Does the body shop have a lamp room used to set the paint? Did they put your car in there without removing the battery first ? This is required to avoid premature aging of the battery.

Check everything else first. Rear Brakes especially. This is done by putting the car on a lift and rotating the rear tires. They should rotate around at least once, probably twice with a good push. If the stop right away after being pushed, something is wrong.

I have been over 58 mpg all summer on 185/65R-15 Hydroedges that had at least 7 K miles on them at the beginning of the summer. I had two tanks over 60 mpg. This is commuting, a distance of 23 miles at a time in all sorts of summer weather, plus stop and go trips on the weekends for errands of much shorter distance.

 

<div class='quotetop'>QUOTE(donee @ Oct 29 2007, 07:56 PM) [snapback]532207[/snapback]</div>

You're brilliant! What great questions!

 

<div class='quotetop'>QUOTE(Rufaro @ Oct 30 2007, 01:45 AM) [snapback]532330[/snapback]</div>

Alignment and get the print out. This is not negotiable, get the hard copy of the alignment. Also, go to your car the next time you can sit down and closely inspect the tires. Check all four, noting the wear patterns on the inner and out treads. It helps if you can cut the front tires all the way to one side so you can easily inspect the treads in the light. It sounds like there is a risk of misalignment.

Misalignment never gets better and the worst way to find out is when you have to buy tires too early. If you see significant wear on the edges not visible on the center treads or one or more tires wearing uneven, it is important to solve the problem in the next couple of thousand miles. You're not going to 'crash and die' but your tire budget _MAY_ be at risk and early detection is the cure.

Many of the tire shops know that they can not (or will not) handle rear wheel alignment. So they may neglect to tell you that the rear wheels are out of alignment or marginal. By getting the hard copy of the print out, we can look at the numbers and tell if your wheels are 'well within spec' or 'on the edge.'

Bob Wilson