I am searching for tires for my 08 Sierra at Costco. When I put in the vehicle information it tells me to select either 245/70/R17 or 265/70/R17. My understanding is that the 265 is about 1" taller and wider and would increase MPG and slow acceleration slightly. I have 245s on there now. Is there any benefit to changing this if both sizes fit or should I just leave it the same?
Tire Size Question
- Thread starter shurguywutt
- Start date
https://tiresize.com/comparison/
Its 30.5" vs. 31.6", which is 1.1" or 3.6% taller. Its also about 3/4" wider.
The answer lies in how you want to use the vehicle (any off roading or rural use) and what does your '08 Sierra have under the hood? If it has the 6.2 L V8 I would upsize for sure.
Its 30.5" vs. 31.6", which is 1.1" or 3.6% taller. Its also about 3/4" wider.
The answer lies in how you want to use the vehicle (any off roading or rural use) and what does your '08 Sierra have under the hood? If it has the 6.2 L V8 I would upsize for sure.
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It's the 5.3 L V8. I don't go off-roading but periodically go camping or haul loads of mulch or firewood in rural areas.
The 5.3 has tons of power to accomodate the upsize. For camping / hauling it would benefit.
In GM Trucks, is there a way to calibrate for the difference in the tire sizes in order to eliminate speedometer & odometer error?
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Just an FYI:
There will be more difference between make/models of tires than a simple size change. Pay more attention to the specs for the make/model and less on the size.
There will be more difference between make/models of tires than a simple size change. Pay more attention to the specs for the make/model and less on the size.
If you’re happy w the 245 size then stay with it. I personally like the 265, if anything, it looks better and you sit up higher.
If you can, I'd strongly encourage you to go taller but narrower.
Most of the time when people go to taller tires that are ALSO wider, the increased weight and rolling resistance completely offset any small gains in MPG from taller gearing.
The problem in 17" truck sizes is that the tall skinny sizes also tend to be E rated, which means rock hard tread the wears like iron but has poor traction. They're also super heavy tires that waste fuel.
SO you want to go as tall and narrow as you can without having to be forced to an E rated tire (235/80r17 is ideal by size, but they're all E rated).
That leaves 245/70 or 245/75 as the next best option.
The BFG Trail Terrain might be a good option in 245/75r17. It's only SL rated for load, so the sidewalls will be softer and you'll get better ride quality. The tire only weighs 40# each, which is very good for a 31.5" diameter tire. The tread is 8.1" wide.
Contrast that with a 265/70r17 E rated tire like the Michelin LTX MS1 Defender. It's also 31.5" diameter and has similar tread width, but it's a whopping 50# per tire, or over 25% heavier.
When the lighter duty tire can still give a total axle rating of 4900#, I see no reason to use the E rated tire on any 1500-class truck.
I ended up going with the 245/70/R17 Firestone LE3s. The 265s were almost $40 more a tire and they didn't have LE3s in that size only ATs.
Got the best deal on them about $192/tire installed with tax and all.
Got the best deal on them about $192/tire installed with tax and all.
There are some e load range 3PMSF rated tires available. Currently running a set of 265/70r17 E’s on my 1500 and they’re fantastic… but yes they are heavy and fuel mileage obviously suffered a little.
I would go with the 265/70r17 - tons of options out there, and they aren't all E rated. I'm going with that size myself.
I'm sure @CapriRacer could comment more, but from the research I have done, width has either little to no effect on rolling resistance, or there is even evidence that the wider the rim/tread patch the LOWER the rolling resistance. I believe tire construction and materials has a much bigger impact than the width.
I'm sure @CapriRacer could comment more, but from the research I have done, width has either little to no effect on rolling resistance, or there is even evidence that the wider the rim/tread patch the LOWER the rolling resistance. I believe tire construction and materials has a much bigger impact than the width.
Width matters because it is one of the things that determines how much thread must flex to go from round (nominal condition) to flat (contact patch).
Partially offsetting that is that a wider tire is doing more flex in the tread and less in the sidewall, and sidewall flex is a major element of rolling resistance.
The Super Single tires you see on some class 8 trucks were developed by Michelin (the X-one I think they call them) specifically because having only four sidewalls per axle (vs 8 with traditional duals) reduced rolling resistance slightly.
But the main consequence of width is that it puts more weight farther away from the axis of rotation. It's not just that wider tires are heavier. It's the the MOI is worse by a factor greater than the weight increase. This has real effects on the energy you will spend accelerating the RPM of the tire and braking it.
Essentially, a wider tire is a heavier flywheel and takes more to spin up and down.
Yes, because 3PMSF is a tread pattern feature only and takes no account of compounding.
OK. It might be time for my lecture on Rolling Resistance:
Long Version: Barry's Tire Tech: Followup on Rolling Resistance and Fuel Economy
Short Version: There is a tread rubber technology triangle involving Treadwear, Traction, especially wet traction, and Rolling Resistance. In order to get improvements in one area another area has to be sacrificed (or both!) Rubber chemists are magicians and they constantly come up with ways to alter the basic relationship, but they can't repeal the laws of Physics (or is that the laws of Chemistry?)
What I am trying to say is that research will improve the compromise, but not eliminate it. However, what rubber chemists can do is only alter the compromise a little bit. I am of the opinion that large tire manufactures spend a lot of time and money on these improvements, so they are more likely to have tires with improved RR.
Tire size by itself has a small effect of RR - on the order of 2% to 4%. Given that tire RR is only a part of what consumes fuel in a vehicle, most people will not be able to tell the difference.
Further, even though a larger tire size is heavier, the weight of the vehicle is so much more that the effect is hardly detectible, even considering the inertial effect more tread rubber has.
Even further, a larger tire has a lower RRC (RR coefficient), meaning that applying a larger tire size effectively improves fuel economy. Add this to the increased rolling circumference, and the effect is a slight improvement in fuel economy - BUT - it's going to be small.
The tread rubber has a HUGE!!! effect. On the order of 30%. That's why OE tires exist - and they sacrifice wear and/or traction to get there.
So does the rubber volume. That means AT and snow tires have much more RR. This could be another 20%.
And Yes! Super Singles have lower RR than a set of duals, but I think there are 2 things going on. tread width, and fewer sidewalls.
Long Version: Barry's Tire Tech: Followup on Rolling Resistance and Fuel Economy
Short Version: There is a tread rubber technology triangle involving Treadwear, Traction, especially wet traction, and Rolling Resistance. In order to get improvements in one area another area has to be sacrificed (or both!) Rubber chemists are magicians and they constantly come up with ways to alter the basic relationship, but they can't repeal the laws of Physics (or is that the laws of Chemistry?)
What I am trying to say is that research will improve the compromise, but not eliminate it. However, what rubber chemists can do is only alter the compromise a little bit. I am of the opinion that large tire manufactures spend a lot of time and money on these improvements, so they are more likely to have tires with improved RR.
Tire size by itself has a small effect of RR - on the order of 2% to 4%. Given that tire RR is only a part of what consumes fuel in a vehicle, most people will not be able to tell the difference.
Further, even though a larger tire size is heavier, the weight of the vehicle is so much more that the effect is hardly detectible, even considering the inertial effect more tread rubber has.
Even further, a larger tire has a lower RRC (RR coefficient), meaning that applying a larger tire size effectively improves fuel economy. Add this to the increased rolling circumference, and the effect is a slight improvement in fuel economy - BUT - it's going to be small.
The tread rubber has a HUGE!!! effect. On the order of 30%. That's why OE tires exist - and they sacrifice wear and/or traction to get there.
So does the rubber volume. That means AT and snow tires have much more RR. This could be another 20%.
And Yes! Super Singles have lower RR than a set of duals, but I think there are 2 things going on. tread width, and fewer sidewalls.
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The Alpine symbol (3PMSF) is the result of a test and while tread pattern has a huge effect, from what I have been able to gather, tread rubber compound does play a role. Which is why All Weather tires exist.
Thank you for correcting my error. Indeed, the 3PMSF affects not just tread pattern but compound also.
I'll leave my prior erroneous post unedited to in the future the context is clearer.
https://www.lesschwab.com/article/tires/what-is-a-3-peak-mt-snowflake-designation.html
