I've been reading a little about low rolling resistance tires (LRR) and it has me curious. Does anyone here actually have a set, and if so what real-world difference did it make over the factory tires? Also, what models are actually LRR? I can't tell from some of the manufacturer websites I checked.
The Goodyear Viva2, sold by Walmart and Sams, is supposed to be a LRR tire. I installed them and immediately lost 2 mpgs, plus they're noisier tha the stock tires. Also, although they have a substantially higher tread wear index, they'll last as long as the stock tires: no more than 35,000 miles.
I bought some Michelin MXV4+ tires about 500 miles ago. I can't really say if the mileage is different because there are many other factors (air temperature, rain, etc.) They are supposed to be LRR. They are definitely quieter, smoother, handle better, and have better traction than the OEMs. Tires get better mileage and are quieter when they are broken in (after about 1000 miles) so it's still early to tell about mileage anyway. I think that you will have a hard time finding tires that get much better mileage than the OEMs. They're pretty lousy in just about every other way though. It's a shame that tires don't have standard rolling resistance measurements. It would help consumers be aware of the differences when they shop, and would encourage manufacturers to make more efficient tires.
<div class='quotetop'>QUOTE(Boulder Bum @ May 2 2007, 04:38 PM) [snapback]434302[/snapback]</div> What I was told by Goodyear the Integrity tire that is stock on the prius is a low rolling resistance tire so please correct me if wrong and if so how does one really tell?
<div class='quotetop'>QUOTE(Boulder Bum @ May 2 2007, 06:38 PM) [snapback]434302[/snapback]</div> When my 2004 Prius got to 44,500 miles, the Integrity tires were about gone. I had done my research and settled on the Michelin MXV4+ "Energy Saving" tires. The attached file shows my MPG results for both the OEM Integrity tires and my MXV4+ tires now at 85,000 miles (about 40,000 on the Michelins. You can see from the data that the Michelins get better MPG in cold weather and nearly the same MPG in warm weather. This is in spite of their somewhat larger circumference (849 revs/mile vs. 8555 for the Integrity tires) which affects the odometer (and speedometer) calibration. As was stated by others, the Michelins perform significantly better in all other respects and may last 60,000 miles on my Prius. I'm very pleased with them. JeffD
Just a couple additional thoughts. First, remember that it will take probably a couple thousand miles to "break in" new tires, LRR or not. I bought my 04 with 15k miles, and the OEM GY Integs, last summer. It didn't take long for me to decide to jettison those for something better. I tried a set of Michelin Hydroedges in the standard size, but they killed mpg and created noise I didn't like. I excercised Michelin's 30 day "no questions asked" return policy (the only string attached is that they don't really refund you, they offer another set of some other Michelins...) and got the MXV4 Pluses, which are LRR. I've put almost 20k on them now, and they just keep getting better. I could rave all night about these tires. IMO, the Touring Edition is superflous -- just put real tires on your basic Prius. Better in all respects than the GY Integs (about the only thing they have going for them is that they are LRR, but they're awful in every other respect). Unless you're fixated on getting every last mile out of your tires, Integs to anything else should be your first upgrade, IMO.
<div class='quotetop'>QUOTE(jdenenberg @ May 2 2007, 08:31 PM) [snapback]434375[/snapback]</div> What psi were you using. Did you check it in the winter?
Thanks for all the stats/recommendations, all. So it sounds like the consensus is that while some tires may get you about a 2 MPG improvement under the right conditions, the main reason to switch is performance (in wet conditions especially)?
I have Michelin MXV4+ Energy tires in the stock size. They are quieter, handle much better, and have much better traction than the OEM tires. Mileage is at least as good as the OEM Goodyear tires. Tom
Low rolling resistance is a relative thing, ie, one model of tire can have better rolling resistance than another, but it's not an on/off thing such that there's some sort of set threshold below which is good and above which is bad.. In general, tires with heavier sidewalls and greater load ratings will have better rolling resistance than tires with softer sidewalls and lower load ratings; in the same way, increasing the inflation pressure tends to lower the rolling resistance, but you may have to go up quite a ways to see a consistent result (eg, using Michelin Hydroedge, I had to keep the tires at 46/44 for a consistent MPG gain; anything lower and the gains were not there or were inconsistent.. Increasing the pressure even higher than these levels resulted in even better mileage, but was well above the max sidewall rating and made the ride quite harsh and noisy.. The ultimate "low rolling resistance" wheel would be the solid steel wheels on trains- being solid steel, they deform only microscopically and roll with relative ease despite the hundreds of tons of weight they carry.. Unfortunately, such wheels also require a specialized road surface (ie, the rails)- low rolling resistance in the wheels is no use if the road surface is soft and deforms (anyone try riding a bike across grass- it's a *LOT* harder than riding across pavement- the bike tires haven't changed, but the road surface has)..
<div class='quotetop'>QUOTE(Boulder Bum @ May 2 2007, 10:32 PM) [snapback]434444[/snapback]</div> Tires have a significant impact on the handling of any vehicle. Ther are actually part of the suspension and drivetrain. Lighter weight tires and wheels provide less dead weight resistance for the engines to overcome enabling better acceleration. Lighter weight tires and wheels also provide better responsiveness of the other primary consumable suspension components (shocks/springs). The softness/firmness of the sidewalls have a definite impact on ride quality where the stiffer the sidewall the harsher the rise and the shorter the sidewall the harsher the ride (in general). Stiffer and shorter sidewalls also provide less "roll" in the corners which equates to generally more accurate handling characteristics. Stiffer and more dense rubber compounds generally decrease rolling resistance and increase the mileage of the tire. Consequently softer rubber compounds generally have better grip on the road (increasing safety and decreasing rolling resistance). Tread patterns have a great deal to do with road noise and wet/dry weather characteristics. A slick will hydroplane at less than 25 mph whereas most normal tires will work properly at highway speeds by channeling water through the grooves. Wider tires often transmit more road feel to the car (when the car tries to "pull" due to the crown in the road for example), and often produce more noise and rolling resistance. Taller tires may provide some increase in economy and shorter tires help with the application of torque (better short term acceleration). Vehicle and tire manufacturers work very hard to achieve the correct balance of properties when matching tires and wheels to a particular vehicle to provide the best overall balance for the car. Under normal everyday driving conditions most people do not notice much of a difference when replacing a stock tire with a stock tire equivalent. However when making more significant changes, tires can greatly affect mileage, cornering, braking, and comfort properties. What is often neglected when selecting major tire changes is the impact of the springs, toe settings, and shocks on the overall balance of the suspension system. On my Camaro (bas example... I know...), when I changed from a 26.1 diameter tire to a 28" diameter tire my gas mileage increased across the board by a full mile per gallon. At the track, my sixty foot times went from 1.5 seconds to 1.6 seconds, and the speed at the end of the quarter mile went from 109 to 111 (in general), and this was taking into account weather conditions (I have a handheld weatherstation), and utilizing a consistent rollout (spotter) at the start. The same type of changes, to more or less effect, will be seen on most vehicles with changes in tires, depending of course on how you drive.
The Michelin web page list Hydroedge and Harmony for the 07 Prius. Anyone have experience with these tiers?
<div class='quotetop'>QUOTE(etyler88 @ May 2 2007, 09:19 PM) [snapback]434395[/snapback]</div> I run (ran) both the MXV4+ and Integrity tires at 42/40 psi (that's one reason that the OEMs went 44,500 miles). Yes I check and adjust the PSI regularly. The lower MPG each winter has several causes: The rubber compound gets stiff and has higher rolling resistance in low temperatures. The organosilicates in the MXV4+ tires mitigates this effect and therefor produce a low rolling resistance. The Prius needs to keep the engine and catalytic converter warm to satisfy the EPA. This means the ICE runs more often in the winter than in the summer. Many of the moving parts also exhibit higher friction in the winter. Your oil, for one (I use Mobil 1 to reduce this effect), tends to be more viscous when cold. There tends to be more water/slush/snow on the road in the winter which has to be pushed aside when the car is moving. This requires work and lowers MPG. ... My average MPG of just over 45 may seem low for a Prius, but neither I nor my wife baby the car for good MPG; We just drive it (often at a very high speed). Sorry for the long answer, but I am an engineering professor and its in my nature. JeffD ps. The Hydroedge and Harmony tires are not LRR and will cause a small decrease in MPG, but they will noticeably improve handling/traction vs the OEMs. They will also tend to have a longer tread life than either the OEMs or the MXV4+ tires.
This past saturday, I replaced the original Integrities with Michelin Pilot Exalto A/S 195/60 R15. Huge difference!!! Even my 8 year old noticed the difference in noise. Handling and shear road grip was way better too. Tire guy put 34 psi in them though and said that I could drop it to 32 if I felt the ride was too rough. However, I'm seeing posts with 42 and 40 psi. Should I have higher pressure? The Michelin MXV4 Plus are being discontinued, btw C.
Hello, I'm new to this site and new to Prius. I took delivery of my new 07 last week. What a great car. Anyway, after reading all these tire issues with the OEM GY's I decided to replace them. I was going to purchase the Michelin MX4V+ but when I called Michelin they told me thay were discontinuing them. So I just installed a new set of GY Assurance Comfort Threads. Cannot believe the difference. This is a great site and I look forward to many years of enjoying my Prius.
<div class='quotetop'>QUOTE(JLPetree @ May 18 2007, 12:56 PM) [snapback]444950[/snapback]</div> I got rid of my OEM tires at 33k miles and put on BFGoodrich Traction T/A. My mpg tanked from 49 down to around 40 on my first highway trip to Boston and back. Don't buy these, I'm taking them back.
<div class='quotetop'>QUOTE(figmentor @ May 23 2007, 09:35 AM) [snapback]448146[/snapback]</div> I am at 36K miles and I will be checking if/when I need to replace my tires. Fathers Day is always a good time because of discounts. Called COSTCO on their $60 Michelin Rebate. They dont have MXV4+ anymore (discontinued). They replaced with Primacy which has a higher tread count (600 vs 420). Anyone tried these? They also recommended Michelin HydroEdge but I read above hurts gas mileage So everyone, what is the best tire for the prius? Doesnt hurt mileage too much with better handling and reduced noise? Do I just go back to the Integritys? Thanks
<div class='quotetop'>QUOTE(gqscientist @ Jun 11 2007, 07:16 PM) [snapback]459783[/snapback]</div> [attachmentid=8859] [attachmentid=8860] Remember mounting, initial and Lifetime balancing, new valve stems, Lifetime rotation, etc. all included !!
