275/70R18 Sumitomo Encounter AT

[theKurt]

Stock- 265/65R18 Michelin Primacy LTX

New Rubber - LT275/70R18 - E rated load - All Weather tire - Tire shop put them at 45psi.
No rubbing. Good clearance.
Stock 18" rims
Stock (sport) suspension
Ride quality seems to be unchanged. I've only put 2kms on them so far but I can report back if anyone needs to know. I'm wondering if/how the increased sidewall will offset the E load 10ply. I have the 6spd manual, so I'm also curious how it will drive with an additional 5% diameter/circumference.

First three pics are the stock tire. Had to adjust the brightness on several in order to see things as its cloudy here today.

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[theKurt]

Quick Update:

Ride Quality - Definitely stiffer over stock, but the original tires are really floppy. I feel like I could have folded them into a pretzel by hand. They are definitely a light duty highway/SUV tire.
Fuel Consumption - Has increased slightly (maybe 0.5L/100 or 1 MPG)/ in City driving. There is a small but noticeable change in the effort the truck needs to exert to get them moving due to the rotational inertia in the weight and size.
Speedometer - Compared the indicated speed to a speed GPS app on my phone - only a 1 kph difference at 100kph. Seems weird, but I didn't check the speedo before changing them.

Note:
OEM Tire Specs -
Weight - 36 lbs
Load Index - 114T
Diameter - 31.6"
New Tire Specs -
Weight - 62 lbs
Load Index - 125S E
Diameter - 33.2"

tiresize.com Comparison
https://tiresize.com/calculator/

TireSize.com Pressure Comparison
https://tiresize.com/pressure-calculator/

Note: Door Panel says stock pressure is 32psi, but dealership had it at 36. Tire Shop set pressure to 45, so I'll drop it to 37-40psi and check the ride quality again.

Comparing the factory numbers to the change in tire size results in this. I didnt expect the load capacity to drop. Not sure what's up with that, but I'm still inside a good safe margin.

 

[Miqie]

Were your original tires the Michelin Primacy LTX? If so, not sure what you mean by 'floppy'.

 

[theKurt]

Were your original tires the Michelin Primacy LTX? If so, not sure what you mean by 'floppy'.

Yep. They were the Primacy LTX.

I asked the shop to throw the original tires in the back of the truck so I could try and sell them. When I went to stack them in the garage I gave them a shake. They flexed and wobbled quite easily in my hands. They are definitely a light duty highway tire. I'll try to get a video and post it, hopefully later today when I get home.

 

[Miqie]

OK thanks. Thought you meant they were super flexible while driving. I have them on my 2024 Sport and they are OK. Nothing special, and I have no plans to go to Moab with them.

 

[theKurt]

OK thanks. Thought you meant they were super flexible while driving. I have them on my 2024 Sport and they are OK. Nothing special, and I have no plans to go to Moab with them.

Yeah, sorry. On the truck they are fine. Pretty good handling, lower rolling resistance and all that for good gas mileage. If you're sticking to pavement, then I'm sure you'll be fine.

I did see on Tirerack that even though they are called an "all season highway tire", the Primacy LTX have crappy snow and ice ratings. I had to go with something a little more all weather for where I'm at so I have the three peak rating in the Sumitomo now. The possibility of snow or ice here in Alberta is pretty much a year round thing, especially if I head out to the mountains nearby.

 

[Tacocho]

Quick Update:

Ride Quality - Definitely stiffer over stock, but the original tires are really floppy. I feel like I could have folded them into a pretzel by hand. They are definitely a light duty highway/SUV tire.
Fuel Consumption - Has increased slightly (maybe 0.5L/100 or 1 MPG)/ in City driving. There is a small but noticeable change in the effort the truck needs to exert to get them moving due to the rotational inertia in the weight and size.
Speedometer - Compared the indicated speed to a speed GPS app on my phone - only a 1 kph difference at 100kph. Seems weird, but I didn't check the speedo before changing them.

Note:
OEM Tire Specs -
Weight - 36 lbs
Load Index - 114T
Diameter - 31.6"
New Tire Specs -
Weight - 62 lbs
Load Index - 125S E
Diameter - 33.2"

tiresize.com Comparison
https://tiresize.com/calculator/

TireSize.com Pressure Comparison
https://tiresize.com/pressure-calculator/

Note: Door Panel says stock pressure is 32psi, but dealership had it at 36. Tire Shop set pressure to 45, so I'll drop it to 37-40psi and check the ride quality again.

Comparing the factory numbers to the change in tire size results in this. I didnt expect the load capacity to drop. Not sure what's up with that, but I'm still inside a good safe margin.

Did you weigh your setup before and after? Losing only 1 mpg going that heavy of a tire is not bad at all

 

[Miqie]

I'll keep the Michelins on. They should be OK. After all I traded in a 2010 Nissan Versa for the truck and it's 6 year old tires got me through several winter storms. Now I have 4WD so I should be OK.

 

[TH_Don]

Comparing the factory numbers to the change in tire size results in this. I didnt expect the load capacity to drop. Not sure what's up with that, but I'm still inside a good safe margin.

You didn't lose "legal" load rating, P-metric and Euro-metric tires have their load rating decreased by 10% in light truck (versus passenger car) use. Your LTs at 37 psi have the same "truck" load rating (2155 lbs) as do your OEM tires do at 32 psi (2141 lbs as per required derating).

 

[TacoFreak]

Yeah, sorry. On the truck they are fine. Pretty good handling, lower rolling resistance and all that for good gas mileage. If you're sticking to pavement, then I'm sure you'll be fine.

I did see on Tirerack that even though they are called an "all season highway tire", the Primacy LTX have crappy snow and ice ratings.

I had these on my Tundra and they were just like you describe. Pretty quiet and drove well but terrible on snow/ice. In 2wd my truck would sit on ice on level ground and just spin its tires. I could not get my truck to move without putting it in 4wd. On flat, level ground! There was no way I could climb my hilly lane in 2wd if it had snow or ice. They would also lose traction easily on dry roads and my traction control came on a lot. I have had Michelin truck tires that I liked, but not the LTX.

I replaced them with Pirelli Scorpion MTR tires and it made a world of difference. Traction control almost never hit on dry roads and no slip or slide on the white stuff.

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