Need your help! Prius 4 tire information spreadsheet

mmmm... so from another thread, it seems that Toyota wants you to inflate the 15" at the hypermiling pressure of 36" only if you have a tire 89S (defined as "Type A"), not if your tire is 91H. And we know the effect of extra pressure on mileage.

So i guess if they delivered some Two ECO with tires marked 91H, they are not fulfilling some kind of promise about the mileage, due to the lower pressure on delivery.

Looking at the spreadsheet, for the time beeing the Two Eco seems to be fitted with the Ecopia 422 Plus: can some owner double check the speed/load index on the wall? And it would be interesting to know the same for the Nanoenergy A29-



PS: According to Tire Rack, the Ecopia 422 Plus 195/65/R15 only exists in 91H version, so actually the Two ECo should'nt be allowed to run the 36 psi pressure...

Bridgestone Ecopia EP422 Plus (H- or V-Speed Rated)

 

My walmart bought 422's are 91H. 44psi max. (Run 42/40) Mine are 480AA not 540AA or 640AA treadwear. Check out the 17" spare wheels? Maybe just brain fade on my part and it's zero out and the trunk is frozen shut... My 15" chevy wheels and spare fit the Prius
422 89S is a 600AA
Bridgestone Ecopia EP422 Plus (S- or T-Speed Rated)

Bridgestone ECOPIA and TURANZA Tires Featured as Original Equipment on 2016 Toyota Prius

 

Thanks for clarifying, i've missed it. Now it would be interesting to know if the Non-Touring Non-Eco have the same tires (i mean the same speed/load parameter) of the Two ECO.

Thanks for this, for us europeans. Bad news, the EP150 is an old tire class B on RR and B for wet. The same Bridgestone have the EP001S A for RR and A for wet, difficult to understand Toyota choice. In terms of FE, the difference btw an A class and a B class could be substantial. We have quite a few Prius and Auris HSD on the forum , using aftermarket EP001S and they go like a charm.

Whether one can extrapolate if the same class would apply to the 422 Plus i do not know.
For the Turanza T002 i could'nt find any european class.

 

maxwell, what chart is that showing type b, that they've gone to 32psi all around in the 15", including the spare, in your post #21?

 

That would indicate a near balanced axle ratio when full of fuel and with two 150lb passengers in the front seats and one 150lb passenger in a back seat that give the greatest load to a wheel. These are Fed code requirements.

Higher psi for the 89S tires because they have lower load to inflation pressure values than the 91H. 1279@max vs 1356@max. Pressure to load is close to linear for these tires. Comparing Bridgestone. Variation in curb weights between models not that significant compared GVWR or the load given above.

Type B gets full sized spare?

 

Sorry krmcg, i can't see in the pic if they are 91H o 89S....

 

89S

 

Right, so according to Toyota you have on a Prius FOUR a (non standard supply Toyo) Type A (89S) as indicated by Bridgestone press release.

If we guess that the 36psi 89S is more fuel efficient than the 91H run at 32psi, tires cannot be the reason of such a large gap in FE btw 2ECO and 2,3,4.....
Then, look for software and engine tuning (or whatever BIG) for the ECO miracle, beeing the remaining known differences not really a way to justify the gap.

According to Bridgestone , all the non-touring Prius US should have the 15" 89S at 36 psi.



PS: As a side note, just some new NEDC and info for Prius IV EU came up. We don't have any ECO nor any trim using the Li-Ion, only Ni-Mh.

The NEDC values are given for the 15" and 17" separateley tested:

15" city/HWY/combined 2,9/3/3,1 L/100km
17" city/HWY/combined 3,3/3,3/3,3 L/100km

So, a 6,5% decrease in FE is measured for the 17".
Absolute values are absolute b***shit , but the difference, for city and medium speed, should be reliable. I do repeat, hypermilers better stay away from Tourings.....

 

For 15" USA gets the type A Bridgestone 422 89S or Toyo NEA29 89S. Europe and Japan are getting the type B Ecopia EP150 91x or ? with a lower psi. That's what I see anyway. What's supposed to be on the 2Eco again?

 

but on page one, the door jamb pic shows 36/35? are we talking usa only?

 

2 Eco placard picture shows 39 psi front 36 psi rear. This different from the table. Could the 2 Eco also have the 640 vs. the 540 treadware rated 422's? Are there variants of the Toyo A29?

 

No other option than the EP150 91H for the 15" in Eu, but the car is not yet for sale, so we don't know if it ends up with some other tire.
From the Bridgestone Press Release, is not quite clear if Bridgestone got some exclusive supply.....

That's the point of confusion. Toyota Prius owner manual does'nt mention the 39 psi option.

 

The placard on the door jam is the law here. Who knows when the manual was created.
Higher tire psi plus higher treadware/lower rolling resistance tire variant plus -70lbs. equals how much MPG gain?

Just because I can: Europe Ships I'm pretty sure
HAMBURG HIGHWAY
EGSUZ 2016-02-12 20:00

BOHEME
EG SUC 2016-02-17 18:00

CAPE TOWN HIGHWAY
EGSUZ 2016-02-29 21:00

 

Needs a Two ECo owner that report the speed/load parameters and threadwear; i would start to question me only then..

You daredevil spy

 

Thanks!

	Tire model	psi	rev/mile
1	P195/65R15 89S	36	833	turns slowest 1.19%; true MPG > indicated
2	P195/65R15 91H	32	843
3	P215/45R17 87V	33	845

Bob Wilson

 

When someone gets a chance, give a management summary:
Does there seem to be any difference in 2 eco tire sub-type or pressure that could account for +4 MPG?

 

There are two effects:

• tire pressure - increasing pressure always improves MPG although 4 psi seems 'modest' and not enough by itself.
  
• tire circumference - this is a type of 'over-drive'. For the EPA tests, true distance is measured by the dyno. The indicated speed and MPG could be off by 1.19%. Hummm, where have we seen that before . . . Oh yea, Wayne Gertes early report.

If Wayne did his testing right, he used a GPS coupled, OBD recorder, the closest to a true metric without adding a 5th wheel and precision fuel flow meter. But we'll have to discuss this technology another day and a different forum. <GRINS>

Bob Wilson

 

A tire pressure change of 4 psi is trivial, any mpg difference would be obscured by other variables, ie: wind, temperature, traffic.

 

yes, but those variables would affect the non eco numbers as well.