New Tire Questions

[robots4joey]

I'm not sure if this is on the forum yet, but I found it in my quest to buy new tires:
2009 Rolling Resistance Efficiency Ratings for 77 Tires | The Similarly Stimulated Saturn

The date is 2009, so it's alot more current than what I was finding! I think I will buy some of the insignia SE200 tires! Right in my price range too!

-Joe

[CapriRacer]

Originally Posted by robots4joey

........The date is 2009, so it's a lot more current than what I was finding!.........

Unfortunately, it actually dates from 2007. You would think they would try to label it correctly, but they thoroughly blew it.

Here's a presentation that includes that data - and more:

http://www.energy.ca.gov/transportat...%20Testing.pdf

[robots4joey]

whoops, thanks...

so my question I guess is: are the B381 tires better than those insignia SE200 tires?

[CapriRacer]

Originally Posted by robots4joey

whoops, thanks...

So my question I guess is: are the B381 tires better than those Insignia SE200 tires?

I hope by now, everyone who looks through these pages realizes that you have to be very careful when comparing tires for Rolling Resistance.

1) You can not compare tires tested in different sizes, at different times, unless you are sure they've been tested to the same test conditions - and even then, you should be comparing Rolling Resistance Coefficients (RRC), not Rolling Resistance Force (RRF).

2) There may be EXTREME differences between tires within a tire line - some due to some tires being supplied as Original Equipment (OE) tires. The Bridgestone Insignia SE200 is a good example where the UTQG values varies between 560AB (pretty good treadwear value, but probably poor RRC) to 380BB (and because both the treadwear and traction values are low, I'm guessing good RRC and the test data bares this out!) Another example would be the Bridgestone B381 - which only comes in 2 sizes and the UTQG treadwear ratings are different.

So to answer Joey's question:

a) If the tire size you are looking for is either 185/65R14 or 185/70R14, the BS B381's are going to give you better RRC than the BS Insigna SE200. Just be aware that many folks have reported poor wear and traction.

b) If the tire size you are looking for is 195/65R15, then the BS Insignia SE200 would be a good choice. Just be aware that many folks have reported poor wear and traction.

c) If the tire size is something other than the 3 mentioned above, you might get better RRC looking elsewhere.

[robots4joey]

Thanks CapriRacer!

I'm probably going to go with the B381's in the 185/70/R14 size... I really wanted to try to increase the tire size... but alas, I think these tires will give a better benefit than taller tires...

[robots4joey]

Hmmm..... I can't find B381's for less than about $120 per tire... Does anyone have a source for them?

I can get Insignia SE200's for only $70 each... are the B381's that much better for fuel economy than one of the other LRR tires out there? that's a $40 per tire premium, $160 for 4 tires, over 4 years at 15K per year, If I get 1% better FE than the SE200's I would only gain +.33MPG. that equates to 4.5 gallons per year, or 18 over 4 years= a total savings of around $54.

Doesn't sound worth the added cost-unless the B381 is really that superior to a SE200.

Any advice? Am I doing my math or estimating wrong? (I've done that b4....)