Pizza Cutters?

[Zimm]

With the factory tires, the odometer was ridiculously accurate. Like, under 1 mile of a difference over a thousand-mile trip. The speedometer was reading under 4% high, so with 3% larger tires the speedo is almost dead on, but the odometer is (also very accurately) 3% off. The gas mileage went down by ~6% with odo change taken into account.
"Trip computer," or whatever algo Ineos uses to estimate gas mileage, was badly wrong before, it is wrong-er now.

They CYA the speedos for speeding liability. I was intending what I wrote to imply they are set to keep the driver 3-5% slow. Everything sounds about as expected. My thumb rule has been 5%ish nominal losses for a nominal tire size increase.

 

[Brad@SuperiorCO]

With the factory tires, the odometer was ridiculously accurate. Like, under 1 mile of a difference over a thousand-mile trip. The speedometer was reading under 4% high, so with 3% larger tires the speedo is almost dead on, but the odometer is (also very accurately) 3% off. The gas mileage went down by ~6% with odo change taken into account.
"Trip computer," or whatever algo Ineos uses to estimate gas mileage, was badly wrong before, it is wrong-er now.

wrong-er is a great description of everything software with the Grenadier. I love my Grin, and I am fine with the bugs. But you would think in this day and age German software would be better. But Nooooo....

wrong-er.

 

[303ChickenMan]

Curious -- what tire pressures are you all running with pizza cutters? I just installed the MT 255/85r17s on mine -- great choice! However, it seems the recommended tire pressures might be a bit much for these tires when I am running light. I think the tires are running a little ballooned out in the center of the tread. I'll plan to experiment unless one of you has already done this work!

 

[Nadir5]

Chalk test?

 

[TCMColorado]

Curious -- what tire pressures are you all running with pizza cutters? I just installed the MT 255/85r17s on mine -- great choice! However, it seems the recommended tire pressures might be a bit much for these tires when I am running light. I think the tires are running a little ballooned out in the center of the tread. I'll plan to experiment unless one of you has already done this work!

The crowned shape on the tread face of the Mickey Thompson tires was my experience as well at the recommended pressure. Through trial and error I ended up at 34 front and 38 rear. The crowning is reduced but not eliminated. Lowering the pressure further results in too much sidewall bulge. The way to potentially eliminate the crowning is to use a rim wider than the OEM steelies, say 8” or 8.5”.

 

[303ChickenMan]

The crowned shape on the tread face of the Mickey Thompson tires was my experience as well at the recommended pressure. Through trial and error I ended up at 34 front and 38 rear. The crowning is reduced but not eliminated. Lowering the pressure further results in too much sidewall bulge. The way to potentially eliminate the crowning is to use a rim wider than the OEM steelies, say 8” or 8.5”.

I’ll give that a try I may also try the chalk test like Nadir5 mentioned. The stock recommendation on the tire pressure seems really high for as heavy as this vehicle is. Softening the ride on tarmac would also be advantageous.

 

[Psignore00]

The way to potentially eliminate the crowning is to use a rim wider than the OEM steelies, say 8” or 8.5”.

Does anyone know if the factory alloys are any wider than the steel wheels?

 

[Nadir5]

If I’m not mistaken, the factory pressures assume a vehicle at full load, so to the extent you’re running lighter, the pressure should be dropped.

 

[Brad@SuperiorCO]

Curious -- what tire pressures are you all running with pizza cutters? I just installed the MT 255/85r17s on mine -- great choice! However, it seems the recommended tire pressures might be a bit much for these tires when I am running light. I think the tires are running a little ballooned out in the center of the tread. I'll plan to experiment unless one of you has already done this work!

I am running 36/38 cold. On I-70, after an hour they are up to 43/45-ish. Around town they stay at the 36/38. I drop them to 20-25psi off road.

 

[Brad@SuperiorCO]

If I’m not mistaken, the factory pressures assume a vehicle at full load, so to the extent you’re running lighter, the pressure should be dropped.

Yes. I am running 36/38 cold. On I-70, after an hour they are up to 43/45-ish. Around town they stay at the 36/38. I drop them to 20-25psi off road. I hope the higher pressure on the interstate on long trips help with gas milage. I have no proof that it will, just hope.