New Tires = Lower MPG?
Because of the faulty rear control arm in the 2006-2008 HCH, all 4 of my tires were cupped and I had to replace them with 4 new tires (see previous post on this).
When you put on 4 new tires, does your MPG suffer for a while? Will it come back again as the tires "wear in?"
I didn't want to put on the same crappy Dunlops that came with the car (2006 HCH), which have a terrible treadwear rating and no mileage warranty. I was looking at the various LRR (Low Rolling Resistance) tires that are out there, and most were WAY too expensive for me (even from the cheapest place out there -- tirerack.com, the Michelins were just under $120 each, as was the new Yokohama Orange Peel tire that's environmentally friendly as well as LRR). That's just the price for the tire (before shipping, before installation, before tax, etc). I was going to put on just a normal (non-LRR) all season tire (the Yokohama Avid Touring S) and then at the last minute decided on the Goodyear Assurance Fuel Max. The Fuel Max is supposed to be an LRR tire.. in fact they advertise that you'll get 2600 extra miles savings of gas with the tires during the normal lifetime of the tire (I'm sure that's inflated, but nonetheless, it's designed to be an LRR tire). Interestingly, the car they used to get that figure (which they say is 4% in their press releases) was the (normal) Honda Civic. Goodyear also makes the OEM tires for the Prius... so I figured OK. Tirerack had them for $79 each, and a local place matched what would've been the final price had I gone through Tirerack and one of their local installers (which was $433 out the door).
Had the tires put on, then went immediately over to the dealership so they could replace the faulty-designed original rear control arm with the corrected one (so the new tires won't cup the way the old ones did), they did a free 4 wheel allignment as well (part of the repair package for the problem). So I have 4 brand new tires, and a complete allignment.
But I've noticed the first 2 days of driving it that my MPG has gone down. Nothing else changed (same tank of gas, same everything else). I'm looking at the "real-time" MPG meter, not the long-haul odometer. But in places that I've driven with the HCH almost every day for the past 3 years, the MPG seems definitely to be lower. In sections where I always get right at the 50 mark on the real-time MPG meter, it was getting under it, and this was a constant thing. About 10-15% less maybe. These are supposed to be LRR tires, fuel-saver tires (with fuel saving results done on a Honda Civic). Same exact size tire as spec, etc.
Just wondering if it's normal with ALL new tires that your MPG will go down at first until they're worn in, or if this is something that'll remain the same as long as I have these tires. I mean, heck, I could've just bought the Yokohamas for $100 less if I didn't want to get an energy-saving tire. So that's why I'm wondering if I just threw the $100 away or if it'll improve back to normal in time ("normal" being having 4 cupped OEM tires that I drove 42000 miles on).
"Just wondering if it's
"Just wondering if it's normal with ALL new tires that your MPG will go down at first until they're worn in, or if this is something that'll remain the same as long as I have these tires"
I think there's several factors at play.
The Goodyear Fuel Max, Bridgestone Ecopia and Michelin Energy Saver are three recent offerings hinting at lower Rolling Resistance, and yet none of these manufacturers seem willing to publicize hard Rolling Resistance data. One argument might be that RR will vary with tire size, but they could at least publish data for tire sizes of HCHII and Prius, for example. I suspect it would take legislation to change this.
When trying to decide on replacement tires you might check out what the the current model year of HCH is arriving at dealerships with. For various reasons this is a statistic not included in the brochures, but you can easily check in person. They're likely still coming with the Dunlops you had, or as in our case: Bridgestone Insignia SE200_02.
It will be interesting to see what they supply with the upcoming 2010 HCH, with this increasing crop of choices claiming low RR. FWIW, at a recent visit to a local exhibition they had a 2010 Prius on display, and I noticed it had the Bridgestone Ecopia's.
If you look at the manufacturers choices for OEM, in particular with their mileage leading hybrids, they're often mundane tires, decent but not great traction. I found our Bridgestone Insignia's made snow tires a virtual *necessity* last winter. With 65,000 km's of wear they were near useless in snow.
Getting back to your immediate concerns, I do think *any* new tires are going to cause a mileage hit. They're stickier, have deeper tread and fwiw have slightly larger diameter. The latter will have your car thinking you've travelled a (slightly) shorter distance.
When you wear your tires
When you wear your tires down, the mpg, (regardless of tire brand) will increase for your vehicle due to a decrease in rolling resistance. This decrease in rolling resistance, (longer stopping distance, slower starts, or tire spin) is related to having worn-out tires. When you install new tires, the tread will grip better, giving you faster starts, and short stopping distances. The extra grip will also give you lower MPG compared to the tires just removed from your vehicle. Over time this will equal out, but keep in mind
I lost 5MPG city and hwy
I lost 5MPG city and hwy when I installed Michelin Pilot Exalto tires. The factory tires must have very little rolling resistance, but also only last for 30,000 miles.