185/65r15 vs 195/65r15 mileage/comfort

My 2004 Prius runs great on 195/65/15 tires. I replaced the stock tires with Pirelli P4s and the overall handling seemed to significantly improve. How much of that was getting quality new tires vs. warn-out crappy tires vs. the 185 vs. 195 size is hard to tell.

I found I lost about 3MPG when I switched but when you factor in the size difference of the tires (834 revs/mile vs. 856 revs/mile) you find most of the difference is just reporting, not actual distance per gallon.

The bonus of 195/65/R15 tires is that the speedometer is actually accurate. With the 185 tires, I was always reading 3-4 MPH over what my GPS or roadside speed check signs would report. With the 195s, things are almost dead-on.

Go with the 195, it is the tire the car was made for.

 

Switch the 05 to Michelin-X 195/65R15 at 40K 80K now with over 50% lost about 1>2 mpg
much/much better ride and handling. Go for it you will think you have a new car..

 

Again...Most of the drop is what the car reports not an actual loss of true distance per gallon. City or Highway...

With 195 tires, when the car thinks you have gone a mile, you have actually traveled 115 feet further than you did with your 185 tires. This is not bad, that 115 feet put you much closer to really traveling a mile. A quick check of a tire size calculator will show the difference.

It takes a little fuel to get you that extra 115 feet (2.2% of a mile) which is why the car is telling you your mileage is a little lower...

The other part of 195 tires is that they are 0.39" wider which all other things being equal will increase your rolling resistance and slightly impact mileage. I think the rolling resistance of various brands is probably more significant than this fraction of an inch in treadwidth but I don't have any data to back up that assertion.

 

Are you sure you don't mean 195/60?

 

A 195/60/15 is going in the wrong direction. It has a 1% smaller diameter than the already too small 185/65/15 stock tire.

The 195/65/15 is 2% larger than the 185/65/15 which is how you get the speedometer to more accurately reflect your true speed.

At least that is my experience after comparing the speedometer to various GPS readings. I made the switch to 195/65 tires several years ago after reading about non-north-american versions of the Prius which came with 195/65 tires as stock. The speedometer inaccuracy issue was discussed then as well.

I would love to hear if your speedometer and GPS reported speed match when using 185/65 tires. That would be new data and would make me wonder if not all cars were calibrated the same.

 

I am going to 195/65/15 as well. Same reason is to get the correct speed reading or true reading. H

 

Thanks for sharing. My next set of tires will be 195/65/15 as I want a true speedo reading also.

 

I just put the Yoko TRZ in a 195/65/15 on my prius about 3 months ago. What pressure are you running in those.. The sidewalls say 50 max, I currently have 40. 32 just seems to low in this bigger tire.

 

That seems to be the average. You have room to go higher if you want better FE! Hal

 

I just didn't want to be in a dangerous range. I might increase to 48/46 and see what happens to the few. Right now I'm at 40-41 with lots of hwy driving and about 7k on these tires.

DROIDX ?

 

After reading this thread I got the 195/65/15 on my 08 Prius at about 41K. Goodyear Assurance Fuel Max. Now I have about 3000 miles on my new tires, the experience is very good and would recommend. With the 185/65/15 integrities my prius has got the VSC enabled numerous times when driving on water puddles on freeway during rain, and it would shake a lot even on streets with high winds of the valley. I used to think it was because of light weight of the car. But with these new set of tires both problems gone, much better control and feel a bit taller. The odometer is dead on (as said earlier), weight capacity increases. No MPG loss after considering the lower rpm. Initially the tire replacement shop had 35 PSI on all 4 tires. I then increased to 45 and 43, there was a problem here. Due to the stiffness and extra height of the tire it would touch the bottom part of the shock absorber when going on bumps or while stepping on potholes. Reduced the PSI back to 37 and 35, that problem almost gone now too.

4 tires, GY Assurance wilth Fuel Max $ 360 (free ship + no tax) + $ 40 mail in rebate from discounttiredirect.com recieved in a week. Paid $ 40 at local tire shop for replacing. Extremely satisfied. Was quoted about $ 525 OTD at a GY dealer for these tires.

 

Sorry to revive an old thread, but I'm curious about others experience with going with 195/65R15s. I need new tires and I'm considering this size, but I'd like to get some more feedback. Any one else have experience going with this larger size??

Thanks!

 

I would advise against it, and only from personal experience. I will have to say that the 195 ride a bit better, but I don't know if that is due to the better quality tire, or the size. The biggest downside that I see with them is the MPG.

The dash reading before switching them out was about 46-48 with 80/20 hwy/city. I could get a bit higher when it was mostly city. With the new tire, about 55K on them now, 80/20 hwy city I am lucky to get 41-42. Not a huge difference, but a difference enough to notice a significant drop in miles/tank. I drive about 150mi a day to/from work so this is sort of a big deal. I am saving now and will be replacing them soon, will go back to 185's.

Just my 2 cents.

 

If you are basing your fuel calculations on your oddo mileage as stated in one of the posts above you are going further than the oddo is reporting giving you inaccurate figures.

In the UK I am using 205/55/16 tyres against the OEM size of 195/55/16. This size gives me a 2.8% under read on my oddo meaning for every 100 miles I record I am actually doing 103 miles. The speedo is more accurate since it normally reads 10% fast.

With careful choice of tyres and factoring in the 2.8% increase in distance traveled I have gained about 3MPG on the OEM tyres. Now at 64.8 MPG (UK gallons) or 58 MPG US

On a tank full of fuel I am going 20miles further than the oddo says.

There is always a break in period with new tyres that at first will rob you of between 3&5mpg also the old tyres being worn will make the oddo register more miles than you are actually going compounding the apparent error.

 

Not only that but those who go with a larger tire and do not compensate their driving for the now accurate speedo reading will obviously suffer worse fuel economy because they are now driving 2+mph faster than they were when their speedo read 2mph too high (all GenIIs do this).

 

I know this is an old thread and it's getting bumped again, but I'm now in the market for tires and debating on size as well. The 185 GY Integrity tires are horrible in anything other than dry pavement and I'd really like to try the Michelin Energy Saver tires. These tires come in the OEM size 185/65/15 and the 195/65/15 size which would help with the speed correction and possibly give more cornering speed. There is only 1 lb difference between the two sizes and I'm wondering how the MPG will be affected. Obviously if I stick with the 185 size the MPG will get a bump, but I'd like to go a little wider and not take a hit in my current MPG.

 

I WOULD NOT go with the 195, no matter the cost difference. I switched from the 185 to 195 when I did my first change from factory at about 75K. My MPG went from 46-47 to 41. I have paid for it ever since. I have about 160K on the car now and am about to buy by 3rd set of tires. I will definitely buy the 185/65/15 's/

And yes, I have over 80k on this set of tires (yokohamas)..and have a little life left, probably 5K or more. I will more than likely buy them again, just factory size.

just my 2 cents.

 

I can't comment on the size difference since I did not get the wider tire, but I did get a set of the tires you are interested in. Take a look at this string.

If you have Goodyear Integrity Tires - Read this | PriusChat

I have definitely seen an increase in the MPG. I have about 900 miles on the new one's now and am very pleased.

Ron