Low Rolling Resistance replacement tires: Current List

Re: LRR and other OEM tires 15", 16", & 17"

OK, I'm trying to tie down a proper list of OEM tires for this and other threads use. Please let me know if you have the UK/EU tire brand/models.

15" Rims (standard aluminum rims in the US 2004-2009)
185/65/15 (2004-2009 Standard U.S. OEM tire size for Goodyear Integrity at 855 RPM)
195/60/15 (2004-2009 non-U.S.A. OEM 15" tire size? Can't find a specific tire for this is it the Goodyear Integrity or something else?

15" Rims (standard alloy rims in the US 2010+)
195/65/15 (2010+ OEM tire size 1 Goodyear Assurance Fuel Max at 836 RPM)
195/65/15 (2010+ OEM tire size 2 Bridgestone Ecopia EP20 at 833 RPM)
195/65/15 (2010+ OEM tire size 3 Yokohama AVID S33D at 829 RPM)
Note: all 3 of these are LRR but only the Goodyear comes in other sizes. The Bridgestone and Yokohama tires are made just for the Gen III Prius OEM tire size.

Also what about UK/EU 2010+ which isn't in F8L's list for 15" tires?


16" Rims (Touring Package only in US 2007-2009 magnesium rims, different in UK & EU?)
195/55/16 UK & EU (2004-2009 OEM EU and UK 16" tire size? Can't find a specific tire for this)
195/55/16 LRR US (2007-2009 OEM USA "Touring package" size for Bridgestone Turanza EL400-02 at 854 RPM)

Note: Turanza EL400-02 isn't LRR at all sizes, in fact it's only LRR in 2 16" sizes for the Prius, the 15" and 17" sizes appropriate for the Prius are NOT LRR. Worse it's a poorly rated tire in terms of traction wet, dry, and snow/ice.


17" Rims (2010 model 1229 aka "package V" alloy rims, 2011 "Plus Performance Package" alloy rims, I know these are right for US, do they sound right for UK & EU?)
214/45/17 US 2010+ could have one of two OEM tires Turanza EL400-02 at 845 RPM which is NOT LRR at that size or Pilot HX MXM4 which is LRR (GreenX) at 844 RPM. Again Pilot HX MXM4 doesn't have GreenX in all sizes, in fact none of the other sizes appropriate for a Prius have GreenX.

Also note that I don't have 2012 tire info yet. I'm assuming it'll stay the same as the 2010 & 2011.

Assuming the Gen II and Gen III Prius use the same RPM for speedometer/odometer we see a range of 829 to 855 used. It's easy to assume the target on the low was 835, with 845 on the mid and 855 on the high, making the overall target 845. But then it could technically be another RPM and the round numbers are just coincidence.

All tire data in this post was taken from tirerack.com. Let me know if you see any errors in information.

 

3 notes about the first post (I believe you are still doing corrections for it)

Goodyear Assurance Fuel Max (Viva Authority Fuel Max at Walmart) is/should be All-season not Grand Touring Summer under the 185/65/15 group.

Primacy MXV4 is not LRR, does not have GreenX in 15" tires according to tirerack.

Kumho Solus KH16 is not LRR according to tirerack

I just updated my tires by RPM list but I'll put that in another post.

 

I'm ready to eat crow on my prior Gen III RPM guess and say 835 is the target based on Mark57's testing at http://priuschat.com/forums/gen-iii...-fast-have-you-taken-prius-2.html#post1399436

Just so I don't run out of crow to eat I'm now guessing the 840-849 block is good for Gen II and since the 835 target seems solid for Gen III I broke the block below that where I did because that block as separated gives you the Gen III choices.

I'm still open to the possibility that the Gen II wants 835 just like the Gen III or that Gen II wants a different RPM than Gen III.

All-Season Tires sorted by Revs per mile.
858 195/60/15 Hankook Optimo H727

852 185/65/15 Bridgestone Ecopia EP422
851 185/65/15 Michelin Energy Saver A/S
850 185/65/15 Yokohama AVID ENVigor##

849 205/60/15 Michelin HydroEdge w/ Green X
848 185/65/15 Continental ProContact with eco Plus###
847 205/60/15 Goodyear Assurance Fuel Max
844 175/65/15 LRR Continental ContiProContact###
844 205/60/15 Michelin Primacy MXV4#
843 185/65/15 General Alimax HP#
842 195/65/15 Michelin HydroEdge w/ Green X
842 185/65/15 LRR Continental ContiProContact###
841 205/60/15 Continental ProContact with eco Plus###
840 205/60/15 Yokohama AVID ENVigor

837 205/60/15 General Alimax HP#*
836 195/65/15 Goodyear Assurance Fuel Max
835 195/65/15 LRR Continental ContiProContact###
834 195/65/15 Michelin Primacy MXV4#
833 195/65/15 Bridgestone Ecopia EP422
832 195/65/15 Michelin Energy Saver A/S
832 215/60/15 Michelin HydroEdge w/ Green X*
831 195/65/15 Hankook Optimo H727
831 195/65/15 Yokohama AVID ENVigor
830 195/65/15 LRR Hankook Optimo H426

829 195/65/15 General Alimax HP#

# Not LRR tire at all or not LRR at this size.

## The rolling resistance of the AVID ENVigor is unknown to me but these are the tires on my 2005 Prius currently. It is advertised as having improved RR.

### Please note that the ContiProcontact and the ProContact with eco Plus are confusingly similar names with differing sizes to get the same accuracy.

edit * bolded tires are the two good choices for the Gen III that break the rule of thumb that 195/65/15 is the size to get to correct the speedometer error most accurately.

edit: did you notice the 175/65/15 that made it into the list? It's almost the same RPM as it's big brother unless it's some sort of typo.

 

Thank you as well. If we didn't challenge each other our information/posts would be lower quality.

I left the dB Super E-Spec out because it's a summer tire. I could do another RPM list for summer tires, and a third for winter tires but at the time I just did All-Season.

 

Before you read too much into revolutions per mile, read this

Tire Tech Information - Tire Specs Explained: Revolutions Per Mile

It would be nice if on the road at a standard load and speed published revolutions per mile accuracy were consistent from brand to brand +/- 2%. Does anyone have any scientific reason to believe that they are?

Some rev per mile numbers are calculated, some are measured and speed, inflation pressure and load and amount of tread wear are not usually specified. I have my doubts about the published data having a reliable +/- 2% accuracy compared to a standardized test.

 

I read that and a hundred times more when I first started looking up all the RPMs.

You'll notice on tirerack some sizes within a tire line (same brand same model different xxx/xx/xx number won't have RPM listed). In some lines 100% of the sizes have RPMs, some have 80%, some have 50%. It varies all over the place. If all they did was wild a** guess there would be no reason not to list an RPM for each size.

So to me that implies there was actual testing or serious math involved for the ones with RPM listed. Of course it could just be some intern at tirerack or Goodyear didn't enter all the data for the Assurance Fuel Max or the table got corrupted on the server or some such excuse.

Even if you assume perfect accuracy it's still a question from one tire brand/model to the next how much the revs per mile are affected when increasing PSI, and it's likely a non linear curve. Meaning RPM probably changes more at half sidewall max than at 3/4 sidewall max.

And yes, I have no idea if the RPM is for an unused tire, for a tire with half tread, or some other point of wear.

But whatever the method for picking RPM at the manufacturer, it is somehow loosely tied back to tire diameter and seems a valid short cut for checking tire sizes that would be worth considering for a car.

As inaccurate as I know RPM can be (tread and PSI variations) the part that bugs me most about it is that I don't know for a fact the actual RPM that is needed to make the speedometer accurate for each car I own. The only way I can find out is to buy tires, mount them, air them up, and test the car for accuracy after the fact. I don't have the funds needed to buy 3 to 5 sizes of tire for each tire I'd like to consider using. I don't have the funds to do that for the 3+ tire models I'd like to consider either. To be really thorough I'd be buying more than 4 of each tire to be sure I had 4 average tires after throwing out any abnormal samples. I suppose I could figure out that only the front tires affect the instruments and cut the need for half the tires but if I tested that far I'd want the spares to be sure I had representative samples.

So short of buying 36+ tires (4 tires x 3 brands x 3 sizes at minimum hoping for no defective tires to skew the data) and spending weeks testing tires on the one car, I've got to find some way to virtualize testing tires I don't own. That comes down to reading other peoples experiences and reading tire data from retailers and manufactureres, and doing the little bit of testing that I can on the 4 tires I buy every few years.

There just isn't a single source of all the info I need to make a fully informed decision so RPMs are just another variable in the wildly muddy process of choosing a set of tires.

Of course you could just pick a brand or retailer and blindly buy whatever they tell you to buy for your car. But if you were that sort of person you probably wouldn't be on priuschat discussing this with us.

 

This might interest you. I ran a spreadsheet on the 25 tires listed in an earlier post in this thread, all but 2 rated revs/mile were within 1% of my calculated value based on nominal tire size. One was 1.1% different and the other was 2.8% out.

The calculated revs/mile assumes that the actual rolling circumference is 97% of the calculated rolling circumference based on tire size. That's a commonly used value and primarily takes into consideration the fact that the neutral axis of tread and circumferential belt part of the tires isn't at the surface of the tread.

 

I would have assumed you would use reported tire diameter to calculated RPM. In your PDF multiple tires withe the same RPM have the same calculated RPM. In reality those tires have differing diameters. For example

185 65 15 Michelin Energy Saver A/S 24.5" 851 849.7 -1.3 -0.1%
185 65 15 Yokohama AVID Envigor 24.4" 850 849.7 -0.3 0.0%

what is the "calculated rolling circumference" for 185/65/15? Are you just using a tire size calculator on the web or doing the math in your spreadsheet?

Tire Size Calculator - tire & wheel plus sizing says 185/65/15 is 24.46" and 850.3 RPM

Tire size calculator says 185/65/15 is 24.5" and 824 RPM

Tire Dimensions Made Simple - Discount Tire says 185/65/15 is is 24.47" and 824.25 RPM

Custom rims, wheel tire packages for your ride - RIMSnTIRES.com says 185/65/15 is 24.4" and 825.3 RPM

and it goes on and on in the google search results.

Using a tire calculator that doesn't match the other tire calculators would bother me if I didn't know which is more accurate.

And even if generic calculations are roughly accurate why go by those when the manufacturer is giving you specifications per tire model/size?

If the speedometer is already 2% off on 185/65/15 and you grab a tire that is another 2% off vs the average 185/65/15 you could be amplifying the inaccuracy or correcting for it depending on the variation. Why allow a 4% swing when you could dial it in to less than a percent?

 

Just to note the Michelin Hydroedge do not come up at either discounttire or tirerack as replacement tires for a 2010 Prius II. Otherwise I liked the idea of these, it seems like LRR makes it difficult in other tires to have really long tire life and that is what I'm looking for!

 

If you really want Hydroedges don't worry about what the search tools recommend pick any of the tires below and you'll be OK

HydroEdge with Green X(Passenger All-Season) for Gen III Prius Choices
-----------------
15" Rims
205/65R15 822 (1.5% slow)
205/60R15 849 (1.5% fast)
215/60R15 832 (best match)

16" Rims
205/55R16 839
215/55R16 829

17" Rims
If you have 17" rims and want these tires you'll need to buy some 16" rims or 15" rims

The closest match on tirerack is 225/55R17 at 782 which is more than 6% off. Most tire places won't sell you a tire more than 3% off and some won't do it more than a couple of percent off.

Instead of using revs per mile another way of looking at it is tire diameter. OEM Assurance Fuel Max 195/65/R15 is 25" and the tread width is 6"

Hydroedge
15" Rims
205/65R15 25.3 6.5
205/60R15 24.5 6.6
215/60R15 25 6.9

16" Rims
205/55R16 24.8 6.7
215/55R16 25.1 7

So you end up with multiple choices that will work on your Prius assuming you have 15" or 16" rims but they will be wider tires and the wider you go the more RR you'll have offsetting the LRR properties of the tire. So from that standpoint if you want the narrower tires you'd go

205/65/15 25.3 6.5 or
205/55/16 24.8 6.7

 

Thanks!

 

I sent Michelin Customer Service two emails, one asking why certain sizes of the Primacy MXV4 were LRR and my size was not, and another one asking why the Energy Saver A/S was not available. I received the following replies that I thought would be relevant to this thread:

MXV4 response:

We show that the Michelin Primacy MXV4 tire design in size 195/65R15 does have the Michelin Green X symbol for low rolling resistance. However, we do have a few sizes that are not low rolling resistance tires. Normally, tires that are original equipment may not have the low rolling resistance technology. However, vehicle manufacture's normally request sizes and application requirements for new vehicles which includes tire load requirements, speed ratings and other tire specifications for handling etc.

When I replied that my tires did not have the Green X marking on them and asked should they have the markings I have not heard back to date.

Energy Saver A/S response:

We have received your recent email with additional questions regarding the Michelin Energy Saver line of tires. Our 195/65R15 91H Energy Saver (part number 14710) is currently being manufactured in Spain. We have a very limited number of tires coming to the US. Those tires are expected to be available for purchase mid to late November 2011. Additionally, our 195/65R15 89T Energy Saver A/S (part number 41536) is on national backorder. The production schedule that we can see is only for the next 4 weeks - this tire is not scheduled for reproduction during this time. We apologize for any inconvenience this has caused.

 

I hate that over-used sentence. It ranks right up there with "Have a nice day!"

 

+1 Totally agree

 

I just ordered a set of Continental ProContact ecoplus tires in the stock 195/65 size from TireTeam.com Saved $55 with shipping over the price from TireRack and tirerack is out of stock. I will report back on the service level from this some what unknown company.