Recommendations For New Tires On 2003 Prius

Michelin Defender is the only LRR tire listed on tirerack.com in that size

Michelin Defender

175/65R14 82T SL 44 psi 23" diameter 905 revs per mile


apparently if you buy 15" rims you can move up to a 185/55R15 tire and then you could get

Yokohama AVID Ascend
185/55R15 82V SL 51 psi 23.1" diameter 900 revs per mile

Yokohama AVID Ascend (H- or V-Speed Rated)

 

I have the Michelin Defenders, and the (now discontinued) Michelin Harmonies before that. Satisfied customer (though I miss the Harmonies, which made less road noise). I put the Defenders on last fall and have since passed the deer test twice - the first time was about a week after I put the new ones on, and was glad I had.

The Toyota spec is for P-metric load index 84, or "XL" tires, which the Harmonies and these Defenders are not. Questions arise, whether the 84 index is spec'd because of the front-end weight, whether standard-load tires are capable of meeting the load spec at all and, if so, whether they need any special adjustment (e.g. higher pressure) to do so.

I had to spend a bunch of time at the library to persuade myself of the answers no, yes, and no. That is, (1) whatever reason Toyota had for selecting XL tires, it wasn't simply for load rating, (2) yes, standard load tires will carry the weight, and (3) no, they don't need any special adjustment above the 35/33 psi glove-box label pressure.

What persuaded me was learning that the P-metric standard load capacities for standard and XL tires are the same at the 35/33 pressures. (That link jumps into the middle of a thread after I got back from the library, but you can scroll up for more background.)

You might not want to buy these tires unless you are also persuaded of their adequacy, so I hope you'll look through the stuff at that link and not just be persuaded because I am. From that link also be sure to check out the bit on the difference between P-metric and Euro-metric standards, because at least the Harmonies were P-metric as specified in the glove box, and the Defenders are not, so for my latest purchase I had to persuade myself that was ok too. Hint: the Defenders are Euro-metric index 82 to the Harmonies' (P-metric) 81.

All of this still leaves the question why Toyota favored XL tires if it's not about the load capacity, and for that I have only speculation.

-Chap

 

Hi !
I live not so far from Santa cruz, San Jose, and I also need a set of 4 new tires for my wife's 2002 prius.

her tires have no thread left at all !

There's a store called
Tire Outlet Stores

that gave me an offer for 4 new 175/65/R14 "Cooper GLS" tires for $69.99 each, and total of $458 including balance and alignment and including tax, means out the door price.

I have 2 questions:

1) is this a fair price for 4 tires and alignment?
2) are the "Cooper GLS " tires any good?

We don't drive fast, just need a quiet reliable and economical tire.
Thanks and sorry if I made this thread a mess.

 

Not a bad price. But, the only LRR tire made in 175/65 - 14 is the Michelin Defender and they will be 30-40 more per tire. Expect to have a reduction in MPG with the Coopers.

 

Hi Thanks for the answer,

How much will be the difference in MPG between the cooper and the michelin? If it's 42MPG instead of 44MPG, then after 10,000 I will be able to save 11 Galons of gas, which is about $40, if I drive them 40,000 miles, I will get my money back, did you try both and can tell me what is the MPG difference ?

I would have to ask this store to order the michelin because they do not have it.
If anyone else have good thoughts about the cooper GLS, I would be happy to hear more.
Thanks

 

Call your Toyota service center and see if they have Sumitomo T4s. That was the replacement tires I have on both our 2003 and 2010 Prius. They can run up to 51 psi and what I used on my wife's car for this:


They work fine on our 2003 Prius:


Bob Wilson

 

You'll see somewhere between 5% and 15% worse MPG with the coopers. Just guessing at 10% turns 44 MPG into 39.6 MPG.

Will you run above 40 PSI? If the coopers have a max PSI of 51 you can pump them up hard to offset the rolling resistance some. If the coopers are 44 PSI max expect the 10% hit, if they are some cheapo tire with a max PSI below 44 then the MPG hit will be even worse.

 

I'm assuming they put 195/60/14 as the tire size on the 2003? Its wider than the 175/65R14 Defender but looks close on the RPMs

Defender
175/65R14 82T SL 44 psi 23" diameter 905 revs per mile

​

HTR T4​

P195/60R14 85T SL 51 psi 23.3" diameter 907 revs per mile​

 

Wow 4.4 MPG is a lot , I doubt that this will be that case, I am running this old car with terrible tires made in china, can't even remember the brand, with no thread at all, and 33-35psi as recommended by the prius book, and I get 44MPG.
According to what you say, I'm supposed to be well over 50MPG with the michelin and 44PSI on them.

no?

 

You have worn-out tires that produce the BEST MPG of their lifetime. Do a little research on this forum and you will see postings when they report 15% and more reduction when they changed tires. If you don't like the answers you get then why did you ask for help?

 

Thanks,
I am not able to understand what have I written that made you think that I do not like the answers.
I was surprised, that's all.

 

The issue isn't that the worn out tires actually get better MPG but just that the display on the car doesn't correct for varying tire sizes and misreports the MPG as the tires wear.

Depends on the speed you drive and the PSI you keep your tires at but you will see a noticeable difference in MPGs just bumping up the PSI and then another even bigger difference buying LRR tires instead of the cheapos.

Take a look at New Tire Tests from Tirerack.com | Page 2 | PriusChat for some old testing data, the range of MPG variation is bigger than what is in that post as they only tested a small subset of the tires on the market back then. You'd have to do a lot of digging to find the exact comparison between any two random tire brand/model tires and then the MPGs vary by size and the names of the tires are intentionally confusing with wide variations of MPGs with only one word or a couple of letters or even one symbol difference on the tire.

I don't know the exact MPG difference for any two tires but I am sure the difference is significant and easily noticed.

 

Thanks, that is interesting, I think that this could definitely happen, because if the tire are worn out, then its diameter is smaller, which means that the speed shown on the dash is higher than the car actually drive(because of the rolls per speed ratio on the transmission), the calculation of the momentary MGP is being done using the air flow sensor data, so the computer knows how much fuel is being burnt momentary, and at the reported wrong speed. dividing those 2 creates a wrong MPG number, and now I completely understand that.

The bad news is that you can't know the real MPG even if you check MPG the old way, of filling the tank, since the odometer reading is also not correct because of the tiers diameter that is now smaller.

in other words, all those numbers mean nothing, the car probably burns the same amount of fuel with worn out tires or new tires from the exact same type, but we just get a different reading due to the wrong speed calculation.

Also, if we look at the different brands, they all have different rev per mile number, I wonder if this can also be the cause for the difference in MPG that someone will get by getting a different brand, but in fact. the car will probably burn the same amount of fuel.

 

Just to put some back-of-the-envelope limits on how much difference any of this can make, I'd note that between tires spec'd 905 revs per mile and, say, 907, the difference is about ¼ of 1%.

As for tire wear, a spec of 905 rev/mile works out to an effective radius of 11.14". The spec for original tread depth is 10/32" for Defender 175/65R14, and the usual legal wear limit is 2/32", a difference of ¼", or about 2¼%, the difference between say, 43 and 44 indicated MPG.

-Chap

 

No, the difference in RPMs per tire is almost nonexistant. Often less than 1% but sometimes up to 2% or so, but the difference in MPGs can dwarf that by being 5 to 15% difference.

The real difference is in gallons of gas used per mile traveled. To know that number you have to track your miles and gallons every time you add gas to the tank. The display on the car is for convenience and is somewhat inaccurate but it is inaccurate in a predicable fashion and buying better tires will show improved MPGs no matter if you watch the pump or the car to get your numbers.

 

Hi guys,
I only now found some more time to call again and ask about tires, I was offered Kumho KR21, for 400$ out the door, it's for 175/65/14, but I see that the load rating is 81T.

I had a chat with a guy from tire rack, he wrote that even though the prius rating is defined as 84, the "gross axle weight" is 985lbs, and the 81T is good for 1019lbs, so actually the 81T can handle this weight.

what do you say, is it safe to use those tires? do you also drive 81 weight rating? right now I have 3 tires with 82H rating, and one with 81T, and they worked fine, they are just too old.

Thanks !

 

See #3 on this thread.

-Chap

 

Great thanks Chap, I read you thoughts, and other things you wrote on other threads and I decided that 81 is OK.

Does anyone know is Kumho kr21 in size 175/65/r14 is a good price for balance alignment and tax, mean out the door price of $400?
should I negotiate it? I'm going to install it tomorrow morning since the old tires are a life threat.
Thanks.

 

Do not bother with the KR21, the price is good, but they wore out at an alarming rate, and even light snow traction was pathetic. For My Prius, I found then very quiet when new and after only a year they were noisy as hell.

Try the Goodyear Viva 2 tires at Walmart. They do not say LRR anywhere, but I found no impact to MPG whatsoever versus my Sumitomo's I had before, and the traction in snow was so good I did not even bother throwing on my snow tires last winter. Handling and grip is excellent and the wear on them was outstanding. Best of all, they were cheap and excellent warranty from Walmart. For the record, I tried Cooper Tires, Hankook's, Kumho, brand tires over the years and I was stunned that the Goodyears, a brand I never normally considered was so great. You will not regret it.