Snow Traction / Tire Pressure PSI Question--Not JL Specific

[DanW]

I am currently running BFG KM2's in 255/80/17 on my 08 Rubicon. They are great in every condition except packed snow. My question is would airing down from the normal 37lbs (cold) to say, 30lbs, improve traction on packed snow, if even noticeable, or would it worsen?

I'm getting ready to buy another set of these, but have thought about 34x10.5 KO2's, for the better snow traction. However, I only have to by 3 KM2's, and they are much less expensive, and they are simply awesome off-road. The KO2's obviously would ride smoother and quieter, but I'd have to buy 4 and they are almost 100 bucks per tire more. Decisions, decisions...

Sponsored

 

[Vegas_Sirk]

The KO2 is snow rated where the KM2 is not. Pretty much every Mud Terrain will not have a snow rating. I personally like the look of Mud Terrains more then All Terrains, but between the less noise, wet traction, and snow performance the KO2 is what I run.

I also run year around at 30 psi, as its what AEV recommends to run with its lift kits based on their valving and spring combo. I can say that since I aired down, I not only a smoother ride, but it does seem to help with traction. Also the tires are wearing more even. So I totally recommend running the 30psi year around. The only down side is if you kept your TPMS you will need to reprogram the dash light using something like a AEV Pro Cal, so you dont have constant low tire pressure warnings.

 

[homerun]

The KO2 is snow rated where the KM2 is not. Pretty much every Mud Terrain will not have a snow rating. I personally like the look of Mud Terrains more then All Terrains, but between the less noise, wet traction, and snow performance the KO2 is what I run.

I also run year around at 30 psi, as its what AEV recommends to run with its lift kits based on their valving and spring combo. I can say that since I aired down, I not only a smoother ride, but it does seem to help with traction. Also the tires are wearing more even. So I totally recommend running the 30psi year around. The only down side is if you kept your TPMS you will need to reprogram the dash light using something like a AEV Pro Cal, so you dont have constant low tire pressure warnings.

How difficult is it to reprogram your TPMS in the computer, do you need a dealer to do it? Can it be done with an OBDII scanner?

 

[Vegas_Sirk]

I used the AEV Pro Cal:

https://secure.aev-conversions.com/shop/procal-module

Key Features:

• Correct speedometer
• "One touch" turn signals
• Clear engine codes
• Easy to use DIP switches
• Recalibrate tire pressure monitor
• Increase engine idle speed
• Optimize ESP performance
• Transfer Case calibration (2012-18 JK Wrangler w/ A580 trans)

 

[The Great Grape Ape]

KM2s don’t improve with airing down unfortunately, there are no sipes to open up, and it’s not so much tread voids with those and more of just making the hockey pucks weaker at digging into snow.

 

[DanW]

The KO2 is snow rated where the KM2 is not. Pretty much every Mud Terrain will not have a snow rating. I personally like the look of Mud Terrains more then All Terrains, but between the less noise, wet traction, and snow performance the KO2 is what I run.

I also run year around at 30 psi, as its what AEV recommends to run with its lift kits based on their valving and spring combo. I can say that since I aired down, I not only a smoother ride, but it does seem to help with traction. Also the tires are wearing more even. So I totally recommend running the 30psi year around. The only down side is if you kept your TPMS you will need to reprogram the dash light using something like a AEV Pro Cal, so you dont have constant low tire pressure warnings.

I've got the Pro-Cal and have already adjusted it. I may just shut them down completely, as I get the tire symbol and red light every now and then. I suspect it is a code that I have a bad sensor somewhere.

I've run lower pressures, but it knocks the gas mileage down a bit. I run the KM2's at 35 to 37 and they do seem to have worn evenly.

I was starting to lean toward the KM2 and then my old JKU suddenly found itself in the shop with a few age related maintenance issues, so the budget is once again a big factor. I can get the KM2 for 231 bucks each and I would only have to buy 3 of them. If I buy 4 and rotate 5, I can get 50 to 100 bucks off, which makes that last tire a VERY good deal. I'll be making the final call on it in a day or so. The KO2s $327 each, and I'd have to buy 4 but would want to buy 5. Yikes!

 

[DanW]

KM2s don’t improve with airing down unfortunately, there are no sipes to open up, and it’s not so much tread voids with those and more of just making the hockey pucks weaker at digging into snow.

Thanks, that makes sense. I just wondered if it would increase flotation and what effect that would have on traction. Glad I've got Canadian friends here who are THE experts on tire performance in snow!

 

[Uhdinator]

The door jam recommended PSI is also accompanied by the max cargo capacity (700 lbs for my 2 dr).
IMO it appears to me that the PSI recommendation is for max rated cargo load. Vehicle recommended PSI is also a trade off of fuel economy and tire wear.

Point being.......I prefer to have a better ride and even tire wear over fuel economy. So I run about 30 psi cold so i'm in the 32-33 range once the tires warm up. At 37 PSI cold you must be at 40 when the tires are warm. To me that would feel like riding on the rims. I think my 2 dr HT PSI is recommended at 36. I have 305/65/17's and they need less than stock psi anyway or they would wear too much in the center.

Sponsored