Tires for Yukon XL???

[m.mcrae]

I know fuel economy and Yukons/Suburbans don't go together, but we are now a family of 6 with sports/kids stuff and unfortunately need a vehicle like this now. We are looking at putting new low-resistance tires on it. Would it be better to go with the stock 265/70/R16, of the narrower but same circumference 245/75/r16?

Is there anything else i can do to this tank to make it better at the fuel pumps? Wheel skirts?

Any help or suggestions would be appreciated, thanks,
Mike

[CapriRacer]

Originally Posted by m.mcrae

I know fuel economy and Yukons/Suburbans don't go together, but we are now a family of 6 with sports/kids stuff and unfortunately need a vehicle like this now. We are looking at putting new low-resistance tires on it. Would it be better to go with the stock 265/70/R16, of the narrower but same circumference 245/75/r16?

Is there anything else i can do to this tank to make it better at the fuel pumps? Wheel skirts?

Any help or suggestions would be appreciated, thanks,
Mike

You want to put on the largest tire in terms of load carrying capacity. A P245/75R16 has slightly less load carrying capacity, so that's the wrong direction. If can fit somethinglarger, that would be good. Check on Discount Tire's web site to see what they say is the largest optional tire.

But tire size has a minor effect compared to other properties.

There is a technology triangle involving treadwear, traction (especially wet traction), and rolling resistance. In opther words, if you want max fuel economy, you'll get poor treadwear or traction (or both!) . Careful selection of a tire will pay dividends in the long run.

With the recent round of tire price increases, we may have crossed over - cost wise - to where the longest wearing tire might be cheapest in the long run. Anyone have a calculation?

[CapriRacer]

Oh and one more thought:

Avoid putting on LT tires unless your vehicle came with them.

LT tires are made to withstand much higher loads than P type tires - but that means those tires are made of materials that aren't good for rolling resistance.

[theholycow]

Welcome.

I think there are other Yukons/Suburbans on here. There are definitely full size pickups, like my 2002 GMC Sierra 1500 4x4.

The two tire sizes you mentioned are so close that there may not be a measurable difference in fuel economy. Are you looking at the same brand and model?

I run load range E tires. It became a tradition after I got a set for free and was more comfortable towing my camper with more capacity, but it also allows me to run up to 80psi pressure. I don't know if the increased pressure makes up for the potential increased rolling resistance from what are probably less efficient tires. If you have P-series tires, you probably have a 44psi maximum, and I recommend inflating to 44. It should not cause any change in ride quality, should improve handling/wear/pothole resistance, and should increase fuel economy.

Worn tires get better fuel economy than new ones, but of course you don't want to tote your kids around on bald tires!

Generally the best modifications you can do are to your driving, not to the vehicle. There are many techniques and strategies that help and cost nothing. One of the biggest ones in general, and applies very well to these trucks, is avoiding using the brakes; when you use the brakes you discard energy you spent fuel to make, and you then have to spend fuel re-accelerating.

• As soon as you know there's a red light in the distance, brake a little bit immediately and don't touch the accelerator until it's green; the plan is to arrive just as it turns green, keeping as much speed as possible.
• Keep a long following distance in front of you, so when the driver in front makes small changes in speed you can cruise along steadily.
• Brake a little less for turns (It's tough when you've got a truckload of kids but when you're alone you can do it).

As for modifications...

• Expensive intake, exhaust, computer, and bolt-on upgrades do not work (unless you are driving like a jerk all the time). Some people (never the ones with good hard data) claim an improvement on these trucks, but the improvement is never enough to pay for itself.
• Grill blocking is a popular modification that costs nothing (or near nothing) but doesn't help.
• Warm-air intake is also cheap/free DIY but ineffective on our trucks.
• Lowering or skirts/air dams/belly pans may help. There's not enough data for our trucks to say for sure.
• Not really a modification, but possibly one of the few purchases that has a chance of paying for itself, is monitoring equipment like the ScanGauge II ($140) or UltraGauge ($70). It shows real-time and average fuel economy data as well as live sensor data and troubleshooting data.

Start a gaslog here on this site. Keep detailed information in it. By doing so, you can get a good view over the long term of what works for you and what doesn't.

What year, engine, and rear end ratio do you have?

[m.mcrae]

Thanks for the advice, out "new" yukon xl is a 2003 with a 5.3L and i believe it has a 4.10 rear end, but if have to find out where i conform that in the VIN. Has anyone had anything to do with belly pans or air lowering kits with these vehicles?

Originally Posted by theholycow

Welcome.

I think there are other Yukons/Suburbans on here. There are definitely full size pickups, like my 2002 GMC Sierra 1500 4x4.

The two tire sizes you mentioned are so close that there may not be a measurable difference in fuel economy. Are you looking at the same brand and model?

I run load range E tires. It became a tradition after I got a set for free and was more comfortable towing my camper with more capacity, but it also allows me to run up to 80psi pressure. I don't know if the increased pressure makes up for the potential increased rolling resistance from what are probably less efficient tires. If you have P-series tires, you probably have a 44psi maximum, and I recommend inflating to 44. It should not cause any change in ride quality, should improve handling/wear/pothole resistance, and should increase fuel economy.

Worn tires get better fuel economy than new ones, but of course you don't want to tote your kids around on bald tires!

Generally the best modifications you can do are to your driving, not to the vehicle. There are many techniques and strategies that help and cost nothing. One of the biggest ones in general, and applies very well to these trucks, is avoiding using the brakes; when you use the brakes you discard energy you spent fuel to make, and you then have to spend fuel re-accelerating.

• As soon as you know there's a red light in the distance, brake a little bit immediately and don't touch the accelerator until it's green; the plan is to arrive just as it turns green, keeping as much speed as possible.
• Keep a long following distance in front of you, so when the driver in front makes small changes in speed you can cruise along steadily.
• Brake a little less for turns (It's tough when you've got a truckload of kids but when you're alone you can do it).

As for modifications...

• Expensive intake, exhaust, computer, and bolt-on upgrades do not work (unless you are driving like a jerk all the time). Some people (never the ones with good hard data) claim an improvement on these trucks, but the improvement is never enough to pay for itself.
• Grill blocking is a popular modification that costs nothing (or near nothing) but doesn't help.
• Warm-air intake is also cheap/free DIY but ineffective on our trucks.
• Lowering or skirts/air dams/belly pans may help. There's not enough data for our trucks to say for sure.
• Not really a modification, but possibly one of the few purchases that has a chance of paying for itself, is monitoring equipment like the ScanGauge II ($140) or UltraGauge ($70). It shows real-time and average fuel economy data as well as live sensor data and troubleshooting data.

Start a gaslog here on this site. Keep detailed information in it. By doing so, you can get a good view over the long term of what works for you and what doesn't.

What year, engine, and rear end ratio do you have?

[theholycow]

Check the RPO codes on the label in your glovebox. Look for codes starting with G. GT4: 3.73. GT5: 4.10. GU6: 3.42. If you see G80 then keep looking, that doesn't describe your ratio, it just says you have the automatically locking rear end.