Tires, what matters more, LRR, PSI, Load, Overall diameter

[minispeed]

Hi All,

Looking for advice on my next tire purchase and was wondering what matters the most for fuel economy.

There is no one tire I looked at that gives me the max in all catagories and is still at a decent price.

So I was wondering what the importance of the various ratings/sizes would be.

I'm going 17 in, 215/65/16 is stock and I want to go 215/60/17 or 225/55/17, most tires have 44psi max but some 51. Am I better off at a LRR large diameter 44psi or a non LRR 51psi with a higher load rating and slightly smaller diameter?

[F8L]

Do you want the most economical answer or the best mpg answer? The two don't always go together.

[gone-ot]

• increasing tire diameter is same as lowering final drive (axle) ratio = lower engine RPMs for given speed.
• increasing PSI trades ride comfort for less tire resistance = better MPG.
• increased tire LOAD rating typically increases tire weight = not good for MPG.
• LRR is overall tire "rolling resistance" = better MPG, but typically at slight expense of handling and wet road control.

[ksa8907]

the biggest factor for mileage is pressure, the higher you can keep the pressure the better, safely of course. LRR tires are great, but dont be fooled!! some tires will sacrifice traction for rolling resistance, do your homework extensively. personally, i would keep the size that is stock. also, i've heard great things about the michelin energy saver a/s tires.

[minispeed]

I know all the considerations, but which is more important? For example I'm looking at:


Michelin MXV4 Plus, $300 used
225/55R17

LRR: Green XLow Rolling Resistance Tire Technology
Treadwear: 400
1521 lbs.
44 psi
10/32"
26.8in
26 lbs.
rev/mile 785

Or new $400 Hankook (bought at the same time as my rims will mean free install and balance so only $40 more than used Michelins)
225/55ZR17
Treadwear: 420
1819 lbs.
50 psi
10.5/32"
25 lbs.
26.8" in dia
rev/mile 775

So in this case the higher load non LRR tire is more PSI and lighter weight. So is it possible that the non LRR will give better fuel economy since I will run either at max PSI?

Thanks KSA8907, I didn't read your post when I replied because I hadn't refreshed.

[BHarvey]

Michelins new Defender in 215-65-16 has pretty much all the good stuff, high load, light weight, LRR 44 psi AND a 90,000 mile warranty!

[gone-ot]

...the "important" one(s) are those that you actually implement & use.

...the "less-important" one(s) are those that you don't implement & use.

[F8L]

For the two sizes you listed I would stick with the 215/60/17 for the narrower footprint and comfort.

BestMPG = Bridgestone Ecopia EP422
Best Traction and value = Continental ProContact with EcoPlus
GoodMPG and traction and value = Yokohama AVID Ascend

The jury is out on the Defender because no one has them yet so we don't know how well they do for mpg.

Make sure you consider price and treadwear warranty when looking for tires. Sometimes a high mpg tire suffers a low treadwear which may make it cost more to run than say a tire with a little less mpg but much higher treadwear. The Ecopia EP100 and the AVID Ascend are good examples of this.

Some great LRR tires do suffer from worse traction or handling but not all. The Energy Saver A/S offers stellar mpg but poor handling and ok traction. The AVID Ascend and ProContact with EcoPlus offers less mpg (but more than a non- LRR tire) but better handling and traction in the wet. I have run or had direct experience with the above tires. I chose the Energy Saver A/S for total economy but if it wasn't available I would have stuck with the Ascend or the EP422.

[euromodder]

If FE matters, I wouldn't upgrade to 17" rims, nor go any wider than stock.

The results regarding FE when going for oversized tyres are a bit hit and miss.
If you go for a larger diameter, don't overdo it, and don't do it using metal instead of rubber.

[minispeed]

Originally Posted by F8L

For the two sizes you listed I would stick with the 215/60/17 for the narrower footprint and comfort.

BestMPG = Bridgestone Ecopia EP422
Best Traction and value = Continental ProContact with EcoPlus
GoodMPG and traction and value = Yokohama AVID Ascend

The jury is out on the Defender because no one has them yet so we don't know how well they do for mpg.

Make sure you consider price and treadwear warranty when looking for tires. Sometimes a high mpg tire suffers a low treadwear which may make it cost more to run than say a tire with a little less mpg but much higher treadwear. The Ecopia EP100 and the AVID Ascend are good examples of this.

Some great LRR tires do suffer from worse traction or handling but not all. The Energy Saver A/S offers stellar mpg but poor handling and ok traction. The AVID Ascend and ProContact with EcoPlus offers less mpg (but more than a non- LRR tire) but better handling and traction in the wet. I have run or had direct experience with the above tires. I chose the Energy Saver A/S for total economy but if it wasn't available I would have stuck with the Ascend or the EP422.

Thanks for the feedback, especially on the ProContact since that is probably my current new LRR choice if I go that way. The Energy Saver AS was what I tried to get on my prius, but with supply issues and a deal on a used wheel/tire set of green x MXV4 @85% I couldn't beat the deal. However acording to tire rack it isn't in any sizes for my car. The thing I don't like about the Yoko Avid, it's heavy, 28lbs in the 225.

Originally Posted by euromodder

If FE matters, I wouldn't upgrade to 17" rims, nor go any wider than stock.

The results regarding FE when going for oversized tyres are a bit hit and miss.
If you go for a larger diameter, don't overdo it, and don't do it using metal instead of rubber.

I always run winter/summer combos and the stock rims are already going to be put to winter use so I have to buy new rims regardless. I had great experience on my miata going 8% over size and seeing a 15% increase. The thing I noticed the most was the amount of time I could EOC. I wish I could find the link now but when I bought my mountain bike I did a lot of research on 26in vs 29in tires and there was a lot of interesting info on angle of attack and coasting. I really noticed it when ridding the two back to back so I'm convinced that a larger diameter can show benefits. I won't be going that much oversize on this car because I also plan on lowering it. I'm a little worried that even the 2.65% of the 215 60 17 may be too much which is why I'm leaning towards 225 55.

I won't be going any larger than 17, even though the look of 18 is nice there are 0 advantages to the 18in tires over the 17 but there is the possibility of advantages for 17 over 16 that I think is enough to offset the weight.