New tires

[Grif76040]

I currently have p265/65r18 tires. I am looking at purchasing the following tires:
Dunlop Rover H/T
LT 275/65R18E1 123R W

Any thoughts about this purchase? Will switching tires screw up my fuel mileage or speedometer?

Randy

[jgroff]

it will screw up both, but i think both will be minor. speedometer you will be going 1 mph faster then your your gauage says. and lt tires weight more so lower fuel mileage

[OldCoot]

What load range are they? The difference in size will have minor effect on mileage/speedometer.

[Platokidd]

Originally Posted by OldCoot

What load range are they? .

according to there web site they would be load range E
LT 275/65R18E1 123R W

[davel1971]

going from a P series to an LT is a much heavier tire. Both in weight and load capacity. Most likely a small mileage drop even when not towing due to extra weight of tires, but the increased load capacity will make towing safer

[MillerTime]

X2 on the E-10 ply, its in the size #s.

I don't think that there will be any noticable difference in mpg or your spedo!

Here's a side by side comparison along with speed difference.
Tire #1 is your 265, tire#2 the 275.
Only about 1/2" difference in overall diameter, going to be very, very hard to impossible to tell any difference other than being a stiffer tire.


MillerTime- Future Sabre Handler!!

[davel1971]

the actual weight of the tires is what will drop MPG slightly, not the size. Tires are part of the unsprung weight of a vehicle, and being heavier, takes more power to get moving.

[OldCoot]

Originally Posted by davel1971

the actual weight of the tires is what will drop MPG slightly, not the size. Tires are part of the unsprung weight of a vehicle, and being heavier, takes more power to get moving.

True, but it will be an infinitesimal amount of mileage difference and the rolling resistance will be less, so it will probably be a wash.

[davel1971]

Originally Posted by OldCoot

True, but it will be an infinitesimal amount of mileage difference and the rolling resistance will be less, so it will probably be a wash.

It will be a minor difference if any. Really there are too many variables to make a call. We don't know what type of tire his current and new tires are, whether street/all-season tread or a more aggressive tread. That makes a big difference too.

[acadianbob]

Originally Posted by davel1971

the actual weight of the tires is what will drop MPG slightly, not the size. Tires are part of the unsprung weight of a vehicle, and being heavier, takes more power to get moving.

X2. I once put a heavier tire on my VW Jetta. I lost 3 mpg on the highway. Also, if this is a "1/2 ton", make sure your rims are capable of accepting 80 PSI.

[MillerTime]

Originally Posted by davel1971

It will be a minor difference if any. Really there are too many variables to make a call. We don't know what type of tire his current and new tires are, whether street/all-season tread or a more aggressive tread. That makes a big difference too.

Being he has a 2014 Chevy, and a listed p on current tire size, im gonna bet that he has the stockers.

I have a 35lb more per tire and wheel on my current 34.5" mud tires compared to the all terrain 30.5" stock size (both 10 ply) and i notice a mpg and brake difference.
....but like OC said there will be less resistance and probably not alot of weight difference on OP's size difference, so probably a wash.

MillerTime- Future Sabre Handler!!

[MillerTime]

Originally Posted by acadianbob

X2. I once put a heavier tire on my VW Jetta. I lost 3 mpg on the highway. Also, if this is a "1/2 ton", make sure your rims are capable of accepting 80 PSI.

i have never found a psi rating on a GM wheel, and was told at work that you can't find that spec listed anywhere.
But always worth looking at when the rims off

[rlocicero]

So much for discussion... P rated tires were designed for comfort and maybe for some casual towing short distances and not for long distance highway towing. Softer sidewall collapses and fosters more heat build up. This leads to a breakdown of the rubber compound. If you are doing any real towing, I strongly urge you to go with the heavier LT tire. you will quickly get used to the stiffer ride, better handling, better cornering, better tread life etc... As far as fuel economy goes, there should be no difference. The LT tire is stiffer and offers much less rolling resistance than the factory P rated "mush" tires. If you are worried about safety and performance, I feel there is really no choice but the LT's. We tow thousands of miles each year and have never had a problem with a blow out. I won't run with anything else.