17" Tires scream PUMP ME UP!

I ran the 17" tires at the recommended 33 PSI front and 32 PSI rear for about 2 weeks, just to get a feel for the car and the tires. My priority is comfort over handling. I pumped them up to 39/38 a couple of days ago, and there is a very noticeable improvement in cornering, highway speed linear tracking, road feel and overall handling. I am not a gearhead, but even I can tell Toyota has seriously lowballed the recommended tire pressures.

Before the change, handling was acceptable and mostly as expected, but still had the usual numb Toyota road feel. Turns and curves were very stable, but a bit muted, and had a bit more flex in the tires than I was expecting from a low profile tire. With the increase, there has been a large increase in road feel and handling, at very little cost in comfort. Yes I feel the road imperfections more, at both city and highway speeds, but the suspension dampening seems to compensate very well for that, and I am not feeling any discomfort or annoyance at the higher PSIs. The highway noise may also be slightly greater, but not enough to care about.

I will try adding a few more pounds, but I doubt I'll want to stay much higher than the current levels, for the sake of my comfort. Bottom line is that the recommended tire pressures should be at least 37/36, even if you are being conservative. It still ain't a Beamer, but it's definitely into Honda territory now. I'm so glad I got the Model V!

OMG! Exceeding the manufacture specified air pressures will cause you to explode the tires and further increase the size of the hole in the ozone layer!

*sits back and waits for the tire pressure nazis to freak out over this one*

LOL

I am new here and have not seen a flame war over tire pressure yet. But everything i have heard is that overinflating will cause less traction and premature wear.
And if you are going through tires quicker, it sort of defeats the purpose of saving all this fuel, doesn't it?
I am not a gear head and may be just be out of touch, is my conventional wisdom too conservative?

Here ya go mate. Have a look at some of thesde threads and it will answer your questions.

http://priuschat.com/forums/gen-ii-...24-integritys-over-35k-miles-50-psi-pics.html

http://priuschat.com/forums/gen-ii-prius-fuel-economy/32512-tire-pressure-poll-where-yours.html

http://priuschat.com/forums/gen-ii-prius-technical-discussion/44327-max-oem-tire-pressure.html

http://priuschat.com/forums/gen-ii-...oting/14383-confused-about-tire-pressure.html

Great, you and I will be like the proverbial blind men and the elephant! I can hardly wait for all the smart people to come out and correct all the misinformation I'm about to state below!

Seriously, there is a difference between the tire manufacturer's recommended maximum tire pressure, and the car manufacturer's recommended tire pressures. These particular tires are rated at 51 max PSI, which I am never going to get anywhere near. The serious hypermilers here tend to run closer to max tire pressures than to Toyota's recommended PSI. Most sane people here try to strike a balance between comfort/ride and handling/mileage. The auto manufacturer is usually recommending relatively low pressures, to ensure their American customers won't complain about the ride not being soft enough. They may have been particularly concerned about that in the case of these low profile tires, which tend to give a harder ride, due to having less of an air cushion. IMHO, they overshot to the point of significantly decreasing the handling/mileage, for very little gain in comfort/ride. Based on my limited knowledge from reading lots of tire threads here, running these particular tires at the PSIs I was talking about will not reduce tread life or traction.

OK, time for the smart people to chime in!

OK, I have learned something today. Thanks.

Please keep in mind that this is related to the Goodyear Integrity tires. I will go out and measure my Nokian i3s which are overinflated as well. We will see if the treadwear is consistent with our findings on the Integrity. I have a feeling that the wider 17" tires may not like to be severely overinflated but since I won't be running those anytime soon I'll leave it up to someone else to test that idea.

No one recommends running pressures over the max pressure "limit" on your specific tire. We just report the outcome of doing so on our own vehicles and let you decide what you think is prudent.

ggood,

Not sure which tires you have; I have the Bridgestones. I didn't last a week at 33/32 (actually 3 days) before I brought mine up to 38/36. Screw the tire nazis, I like the road feel better at the higher psi and, at 450 miles so far, I've already exceeded 51MPG on my usual commute that yielded 44-46 MPG with my well broken in 2006 with 71,000 miles.

Bottom line, 33/32 won't kill you, but for me, it's too low, soft and bad for tire life/safety. Buy a tire pump, don't exceed the maximum psi, but play with the pressures until you find pressures you and your MPG's like and enjoy your new toy.

I got the Toyos. Already had a pump, so I'm good to go. Had to really hunt to find that TPM reset switch the first time!

I'm starting at 42/41 when I get the car (based on PM exchanges with someone who already has the car and is getting great mileage and handling). Where is the TPM reset switch? BTW, how do you deal with the TPM issue with winter tires (sorry if off topic)?

Get down on your knees and read the tire pressure on your tire and it gives you a Max pressure and stop reading the manual.

My Prius V is due into Newark on June 22nd, but I have first hand experience that confirms your experience.

I currently have a Jaguar X-type, non sport suspension with 17 inch Bridgestone Pole Position tires. Recommended tire pressure was 30/30, but when equipped with the sport suspension the OEM tire pressure was 38/35.

I pumped up the Bridgestone's to 38/35 and found handling/tracking much improved with a minor increase in ride stiffness. I have driven them over 15K miles and wouldn't think have going back to 30/30.

I plan to set my 2010 Prius V to 38/35 or thereabouts as well which seems to follow the experiences being shared above.

TPM switch is located beneath the lower dash, in the area beneath the steering wheel. It points down, rather than facing out, so it's difficult to see (the picture from the manual made it look like it was facing out and was more to the right of the wheel). You pretty much have to feel for it.

When replacing tires and wheels, you have to install tire pressure warning valves and transmitters. The valves and transmitters have unique ID codes that have to be registered with the TPM computer and then initialized. The registration process probably requires a dealer or someone else with the scanner tool. I think, but am not sure, that the valve and transmitter from 1 tire can be moved to a new tire, but someone smarter than me needs to confirm that.

Before I turned on my new Prius V, I pulled out my portable pump and showed the dealer how it worked and what pressure I'd use.

The recommended 33/32 or 32/31 seemed quite low, even though the 215s have a good bit of additional tread contact area. I measured the PSI (tires were cold) before inflating and found that they were already at 38 (sidewall max is 51). With the dealer there, I decided to set the pressure at 42/41. I ran that pressure for nearly two weeks. Yesterday, I bumped up the pressure to 44/43. The little bump didn't seem to change anything.

I haven't yet thought about whether I'll go higher. I haven't felt anything unusual, and I've been able to put nearrly a thouseand miles on the car.

Good question. I hadn't really thought through that issue myself until now. Thanks for bringing it up.

If you are mounting the winter tires to the original wheel I don't think there will be a problem because the transmitter is attached to the wheel. It should be the same as fixing a flat. If you are using other wheels, as I plan to, it should be find to go ahead without transmitters in the wheel and ignore the resulting TPM warnings--at least I hope so. You might want to check tire pressure manually over the winter, but no big deal.

BTW, if you have the storage space I recommend not using the 17" original wheels and instead getting the winter tires mounted on a set of 15" wheel, either steel wheels or used wheels from at least a Gen2 Prius (from other posts, I believe they have the right offset etc.). Downsizing from 17" to 15" wheels will require a narrower tire, which is what you want for snow, and will keep your nice 17" wheels away from the salt. It's also a lot cheaper than having to unmount, remount, and balance tires twice a year.

You can probably find used 15" wheels on craigslist. Or you can order pre-mounted and balanced tire and wheel packages from places like tirerack.com this fall.

Actually, there seems to be a thread on the TPM subject. I assume it is still valid for 2010. I haven't read it all, but it has some more points to consider -- like the risk of having the tire shop break one of your transmitters, which has happened to my wife and is another reason for separate winter wheels....

http://priuschat.com/forums/gen-ii-...roubleshooting/26135-tpms-summary-thread.html