How about a real thread about TIRES?

Hydroedge are rated for 85,000 miles vs 50 or 60 for other tires so when you factor the price over the life of the tire they are really not that much more of an expense!

 

The TireRack says the Dunlop SP Sport A2 Plus weighs 19lbs (in the OEM 185/65r15 size)

I installed a set of these this week immediately after taking delivery of our new Prius. Town Fair Tire gave me $40 credit for each Goodyear Integrity with 16 miles on them. This brought the cost of the upgrade to $160 installed.

If you go to a Goodyear dealer wanting to exchange your Integrities for performance or snow tires in the OEM size, consider Dunlops. Since Goodyear bought Sumitomo shares for control of Dunlop in the US, I found a Goodyear Dealer who would give me a good credit on the OEM towards Dunlops. I couldn't find a Goodyear that I wanted so that helped. They wouldn't give me credit for other brands. (Town Fair Tire matched their deal.)

Does anyone have experience with the:
Continental ContiProContact (CH95 successor and MXV4 competitor),
Falken Ziex ZE-512,
Sumitomo HTR H4, or
Sumitomo HTR 200 (summer tire in 195/60r15)?

I am interested in these partly because they are reported to have low rolling resistance and have maximum inflations of 51 psi.

I recently experienced how the significance of a tire pressure change can vary between tires. I replaced the Michelin MXV4's on my Elantra with BF Goodrich Traction T/A H series. I noticed a 3mpg hit at 30psi. When I inflated them to 38, I found the mpg and coastdown difference nearly disappeared. On the Michelins the mpg, coastdown performance, and ride responded little to the inflation pressure, but the braking traction really suffered and the lateral (turning) traction really improved at the higher pressure. With the BFG Traction T/A's it's been the opposite. The higher pressure notably improved (lowered) rolling resistance, hurt ride quality greatly, and had little effect on handling or traction.

 

<div class='quotetop'>QUOTE(barbaram @ May 12 2006, 03:55 PM) [snapback]254245[/snapback]</div>

Out of curiousity, do others think is it worth the extra $21 per tire (on TireRack-$84 for the 4) to get the Hydroedge over the Goodyear Comfortread? The Hydro is $97 with 90K warranty and the Comfortread is $79 with 80K warranty. The tirerack comparison is shown here

They list a $25 gift card with the Goodyears, but the link is dead. We are looking to get a new set in the next couple of months.

 

<div class='quotetop'>QUOTE(micheal @ May 21 2006, 01:12 PM) [snapback]258905[/snapback]</div>

I can't speak for the HydroEdge, but am happy with the Comfortreads. They are quiet and do not get harsh when running at 40/38psi and definitely are better handling than the Intergrities. We have the Avid H4s on our Honda Odyssey and I think they would be fine on the Prius as well. They are also a quiet and soft (as opposed to harsh) riding tire.

 

I ran my Integrities mostly at 40/38 psi. Here are my measured wear results (also in my knowledge base article on Bridgestones).
Tread_Depth_(mils)____Integrity_after_40,080_rotated_every_10k
________FrontLeft__________FrontRight__________RearLeft_____________RearRight
Inside____14__________________15________________17___________________13
Middle___12__________________15________________16___________________13
Outside__ 10__________________11________________12___________________12

Tread_Depth____RE950_after_4,500_(no_rotations) mostly 36/34 psi
__________FrontLeft___________FrontRight________RearLeft______________RearRight
Inside_____26____________________27______________28____________________29
MiddleIn__32____________________33______________32____________________32
Outside___26____________________27______________27____________________27

I now have 40k miles on the Bridgestones and they are probably about 5k miles from needing replacement.

IMHO the "ruler on TOP of the tire" test for over inflation is meaningless. The shape of the top of the tire pushing against air has little to do with the complex forces forces acting on the contact patch of weight, alignment, drag, sidewall stiffness, etc. Go look at Indy or F1 front tires on a parked car. The alignment and pressures would appear to allow almost zero cornering force, yet the CONTACT patch is ideal. Yes it is an extreme example, but it illustrates my point.

 

<div class='quotetop'>QUOTE(Begreen @ May 21 2006, 01:26 PM) [snapback]258913[/snapback]</div>

Did you notice a decrease in mpg when you got your Comforttreads? Mine dropped drastically and has become very inconsistent. I've tried 42/40 and 44/42 psi, now I'm going to go to 40/38 and see if that makes a difference.

 

It's good to see a spirited tire debate here! B)
I participate in a couple of Porsche forums and tire debates reign supreme. If you were to lay all the tire experts in the world end-to-end, they'd all point in different directions. Since I don't have a stake in any of this (for another 30,000 miles hopefully) I'd like to share a couple of thoughts about tires.

Stiffness - In general a higher performance tire will have stiffer sidewalls to hold up on curves. Sometimes this can be felt by the occupants of the car as a harsher ride. But usually you will be more effected if you have tires that are...

Lower profile - tire sizes express profile as a ratio of height to width. For instance an OEM Prius tire is 185/65-15. This means it is 185 mm wide at the bead, fits on a 15 inch diameter wheel, and the ratio of heighth to width is .65. This is a fairly high profile tire, which means it has a lot of vertical sidewall to absorb road shock. It also flexes more around curves and reduces traction. By comparison, a lot of high performance tires are in the .35 to .45 range. They have very little sidewall to absorb road shock and therefore give a harsher ride, but they don't flex as much.

Tire compound - High performance tires are alomst always made of softer, stickier rubber. They wear out like crazy but have a lot of traction. I have a friend with Porsche Turbo who goes through tires so fast it costs as much per mile for tires as for gas (we've done the math together). But sticky rubber also adds rolling resistance so these kind of tires would definitely defeat the Prius goal of high mileage.

So let's face it. The Goodyear Integrities are a compromise that offer low rolling resistance and adequate comfort at the expense of traction and handling. The tradeoffs between mileage, comfort and handling can be very complex. It's good to see there are people on this forum who are experimenting with other tires. I'm glad to see comparisons so when my time around I'll have plenty of good data to go on. Thanks everyone!

 

<div class='quotetop'>QUOTE(talonts @ May 12 2006, 02:35 PM) [snapback]254220[/snapback]</div>

Try the Mich Radial DT - They work great on my 2006 with no drop in mileage over the Goodyears. They are considerably cheaper than the Hydroedge and are available in the proper size. Only sold through places like Costco, Sams Club etc. If you get them through Costco, they will be filled with Nitrogen, which is an advantage. For what it's worth, CU rated them higher than the Hydroedge in most everything including resistance to hydoplaning. Go figure.

 

I got the Michelin X radials from Costco installed on both my Prii. I have not noticed a decrease in mileage. The cars seem to handle better. These tires were actually the second highest rated tire from Consumer Reports, just below the Triple Treads. They were rated higher than the Hydroedges, even for hydroplaning. Tires have an 80,000 mile warranty and Costco includes road hazard, free flat repair, and nitrogen fills for free. With the special, until the end of the month, they were $330.00 out the door, tax included. I'm very happy with them.

 

<div class='quotetop'>QUOTE(stan @ Jun 22 2006, 10:52 AM) [snapback]275341[/snapback]</div>

I believe you don't have to limit yourself to any tire store/installer by what they sell from their stock. You can always ask them to special order any tireset , so you get the benefits of installing there with the tires of your choice.

Even if they won't special order, you can order through places like Tirerack, and bring it (or drop ship it) in for them to install.

 

The taller stock tires on the Prius contribute significantly to the comfort of the ride, or ride quality. A taller sidewall will also be more prone to treadwear fluctuations based on pressure changes. The "perfect" tire is a tires whose footprint, or contact patch width, is exactlt the same as the wheel width. Any more or less and you change the dynamics of the tire and not always for the better.

Performance tires for corner typically have softter rubber compounds and shorter sidewalls. The softer rubber provides more traction and the stiffer sidewalls resist roll. The tradeoff is is a harsher ride and "tracking" which is where you feel the drooves in the pavement surface through the steering wheel. The wider the tires the more significant this effect becomes.

When I drag race a front wheel drive vehicle, like a Susuki import or Chevrolet Lumina, I have found that the least amount of tire slippage occurs around 14 pounds of pressure in the fron and 45 pounds of tire pressure in the rear. Of course I cannot corner this way so it is not practical for street use. The reason for the extreme pressure differences is to reduce rolling resistance in the rear and provide maximum footprint for the front, as the front end comes up under acceleration even in a front wheel drive vehicle.

The street legal performance tires, such as "drag radials", by BFG or Nitto both actually handle quite well under normal inflation ranges with shorter sidewalls but the reduced tread depth and soft rubber compounds make them unsuitable for heavy rain or longevity.

Harder compound tires last longer in street driving conditions, however their hard compound creates a rougher ride and less traction.

In my opinion...

The ideal setup would be adding lighter weight aluminum rims to reduce unsprung weight. On the front, if you have no cold weather, go with a tire that is a bit softer compound but retain a higher "profile" to retain the smooth ride characteristics. Get a tire with increased tread depth to enhance traction in wet weather.

On the rear use a tire with a harder rubber compound in a slightly more narrow width to reduce the rolling resistance and offset the increased rolling resistance of the front tires. Plus they will last longer.

This process does away with tire rotation practices and you will replace tires in pairs and not all four at the same time.

I would recommend continuing to play with tire pressure. Always use the same gauge. Gas station gauges are far from accurate as are the pencil gauges typically used by tire shops. Buy a decent digital gauge that will register in half pound increments.

Do not worry about the "recommended" pressure as long as you are close to it you will be fine.

Always, and I mean always, check pressure only on a cold tire. The only way to have an accurate basis for measurement is on a cold tire.

When I do a burnout in my camaro the tire pressure is always 13 and one half pounds cold. As long as I burnout the same way every time for the same amount of time, the tires will read 14 and one half pounds when I launch the car. However the measurement is always taken cold and with the same gauge. Other gauges will register something different than mine most of the time. The important thing is that by using only one gaige every time the results will be accurate to themselves so you retain a benchmark for comparison.

If opne shops sets your tire pressure at 40 pounds one day and a month later you have them set it to 42 pounds, unless the tires are the same temperature, the gauge is the same gauge, and the mechanic is the same mechanic reading it the same way, your results will not be accurate.

Not to be a bag, but after eight years of racing I know that half a pound of tire pressure can change my 60 foot time by as much as three hundredths of a second in the blink of an eye.

This is my opinion. Your results may vary.

 

Do yourself a favor and get something from the Toyo Proxe series. They are unidirectional for maximum performance (only spin one way so take in mind during tire rotation) they look great, and mine haven't worn that much under heavy driving and even burnouts. They also take rain very well. The problem will be finding some made to fit a 15 inch rim but I'm sure they make some. My tire is the Toyo Proxes 4.

 

<div class='quotetop'>QUOTE(GasGuzzler87 @ Jun 22 2006, 04:09 PM) [snapback]275405[/snapback]</div>

I had the Proxes on my 2000 Maxima. Very good handling, decent in rain/snow (I used them year round) and fairly quiet. I can't say how they affect MFG though.

 

Let's not forget that ride quality is also due to other key factors such as:
1) Side wall of said tire (which has been kind of touched on)
2) Strut condition (blown entirely, scratches on the pistons, leaking fluid)
3) Suspension bushing condition (cracked, pieces completely missing)
4) Wheel bearings
5) Engine mounts
6) Lower tie rod ends
7) Rotor condition
8) Alignment
9) Tire condition

If any of these items is broken or worn, it is definately going to be felt through the steering wheel. The suspension will also feel unsatisfactory.

Also, when inflating a tire it should NEVER be inflated to the specified MAX psi. That is a max...never put the pressure there. 1-2psi below the max is sufficient. Remember, as a gas heats up it will want to expand. In an encloser this equates into more pressure. So, if you set your tires at max when they are cold then go for a long drive, you have now exceeded the manufactuars specifications and run a risk of blowing a tire.

For myself I am used to a race inspired street tire. So my choice would be an Azenis 615. They are unidirectional, a very supportive sidewall and they handle in rain very well. Tread life is also fantastic.

 

I replaced my Integritys about 1500 miles ago with Toyo Proxes TPT 205/60R15 91H, this size comes in both V and H ratings. I chose the H because it is a little lighter but still weighs 19.8 lbs vs 17 for the Integritys. The TPT is also available in the stock 185/65R15 88H size which only weighs 17.2 lbs. I used the 205s because I wanted better handling and braking, thus wider tires. The 205/60R15 size is designed for 6 inch rims which the Prius has. The revolutions per mile for the 205/60 size is 847; the stock Integritys are 855 as are the 185/60 TPTs.

I found the slightly larger diameter of the 205/60s actually corrected some of the speedometer error. With the stock tires the speedometer was almost 2 MPH fast at 70 MPH, now with the 205/60 tires it is about 1 MPH fast. I checked it against a good quality hand held GPS receiver.

Fuel mileage at freeway speeds seems unchanged. I originally posted in another thread that I thought the around town mileage was unchanged also but I'm not so sure of that now. I may have lost 1 or 2 MPG but I can't be sure because there is no objective test I can do. If I have it's a good trade off. The car is more stable, has better tracking, and must have better handling and stopping distances.

 

<div class='quotetop'>QUOTE(priusstreetracerFTW @ Jun 22 2006, 03:38 PM) [snapback]275428[/snapback]</div>

This is about tires I'm assuming that all other parts of the car are stock and properly working. The sidewall will always be the same because he said he is using the stock 15 inch wheels. PRoxes FTW.

 

<div class='quotetop'>QUOTE(Jennjay @ Jun 22 2006, 02:01 PM) [snapback]275349[/snapback]</div>

I agree with your assessment of the Mich Radial DTs (wrote the post just above yours). One correction though, CU rated them just below the Triple treads. They were rated much higher than the Comfort treads. With Costcos rebate now, they are a great buy.

 

I purchased the Michelin MXV4 Energy tires from Costco to replace the factory tires that were on there.

The performance ratings for the tire are:
Tread Life: 9
Wet Traction: 6
Quiet Ride: 9
Handling: 6
Winter Traction: 7

http://www.michelinman.com/catalog/tires/M...retype=2&tire=5

As for comfort, it is definatelly a MUCH smoother ride, and handling has increased more. I live in the San Francisco Bay Area, and I take Grizley Peak Road to Moraga twice a week, and the handling is SOOO much better now wiht hte MXV4 tires.

But - when I went to purchase the tires at Costco, the sales people did thier LEVEL best to keep me from purchasing them saying that the tires wear faster than the recommended tires for the Prius.

Needless to say, I had them install them anyways. I travel 95 miles every day, so a comfortable ride is much more important to me than performance, but these tires do make the difference though.

 

Thanks Stan, I edited above so it will not contain erroneous info.
The Michelin X's seem to be the best overall tire out there for cost, longevity, and perfomance
Consumer Reports rated them above average in all situations, except snow and ice ( rated as average, as were the Hydroedges)- of course those are two driving concerns I do not have in Florida