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Discussion Starter #1
Interesting data for Bridgestone B330evo users:

I have on the front side Bridgestone B330evo, and rear Bridgestone B391's.
Interesting is that I have an increase of 15 % in my fuelburn !
Normal I have an avarage of 90 mpg, now with the B330evo's 71 mpg.
Tire press is 43 psi- 3 bar.
I asked the supplier for data:

Weight B391: 5.8kg. Profiele depth:7.1 mm
Weight B330evo: 6.9kg. Profile depth:8.4 mm

Difference is 1.1 kilo per tire, I have only 2 evo's and that is causing already 15% more fuelburn :!: .

Next week I will be back with the OEM tires, the good old B391's.
The supplier also told me that the B391 is only develloped for the Insight.
 

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Also take into consideration the difference in tire diameter/circumference.
It changes the fuel consumtion values displayed when different diameter tires are used because the speedometer and odometer readings are off.
The best way to confirm is to compare your speedometer with a GPS.
GPS is not very accurate at determining absolute position (+/- 10 to 30 feet it common) but it's fantastic at determining speed (+/- 0.2 km/hr is common).
 

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Discussion Starter #3
Both tire sizes are 165-65-r14, so there is no diameter differential.
But it is thru that gps shows a 2% difference with the car's actual speed.
 

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Check the actual diameter of the tires in the spec sheet. Just because they are both 165/65R14 doesn't mean they are exactly the same.
But because they are both the same brand they are likely very close in diameter.
 

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To my knowledge the OEM tire on every Insight ever made is the Bridgestone Potenza RE92 165/65R14. The B381 is deffinitely a low rolling resistance tire as well (they used it on the 03-05 manual transmission Civic Hybrid), but I have seen no numbers to compare the two.
 

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Changed from 330 EVO to 391 pattern and better mpg.

I had two 330 EVO tyres on the front of my Insight when I bought it, and it could never achieve quite the mpg of our other car, a 391 pattern shod Insight.

Replaced them today and mileage has gone up probably 5%.

Difficult to be exact but I recommend people do use the oem spec tyres.

RE-92 in USA

OR

391 IN UK.

Regards

Peter
 

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ret - in Australia the OEM tire (currently on my Insight) is also B391 165/65 R14 79T. Do you know if this is this the same tire as an RE 92 just with different names?

I need to replace the current tires and was thinking about the Michelin Energy XM 1 tires that are used on the Prius here. Any thoughts on comparable fuel economy?
 

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Interesting, I do know the B381 is LRR certainly, but didn't know it was available in a 165 series... maybe just not in the state. Are they made in Japan? I know the 03-05 Civic hybrids with 5 speeds got the B381's, but those are a 185.

I learn something new every day.
 

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the first insight that came to the UK for technician training is still at Honda Institute - it has the B391 fitted - AFAIK the original tyres
 

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While there likely is a loss in efficiency, it's probably not as significant as it may appear initially after switching tires. There are two factors at play:

1) Rolling resistance continually goes down as a tire wears out. This is because a major component of the rolling resistance itself is the treads deforming, as these wear and become shallower, they will take less energy to deform. There is also a "breaking in" effect of the rubber.

2) Actual Tire diameter is reduced as a tire wears out, this will lead to slightly more optimistic odometer readings over time.

This means that switching from any well broken in, slightly smaller diameter (twice the loss in tread depth) to a brand new one will lead to an apparent loss in fuel efficiency.

Difference is 1.1 kilo per tire, I have only 2 evo's and that is causing already 15% more fuelburn
I doubt 2.2 kg the mass of the tires is making a very significant difference in mileage. Assuming that it is all located on the treads, it will act as the equivelent of twice the mass, or <0.5% increase from stock.

The tires themsevles likely have more rolling resistance from the extra tread depth, and different rubber composition.

Finally, placing the higher-rolling-resistance tires on the fronts will make more of a difference, as they are bearing 60% of the car's weight. Rotating them and comparing the mileage would be a good experiment to see what their rolling resistance is, compared to the two stock wheels.
 

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Discussion Starter #12
Finally I got my b391 tires and for shure........from 3,5 l/100km it dropped to 2,8 l/100km, both tire pressures @ 3 bar. 8)
 

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Very nice! you now have an official "3 Litre" car! ;)
 
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