Overlander
Senior Member
- Joined
- Sep 12, 2020
- Posts
- 370
- Reaction score
- 533
- Location
- Oregon
- Ram Year
- 2021 75th Aniv Build #0006
- Engine
- 6.4 Hemi
Any balancing issues with the A/T3W?
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
thanks. slightly more than I would have guessed. I run a bit less psi tho.34.75” mounted and aired up, with no weight on them...
View attachment 226980
With the weight of the truck on the rear at 58psi they measure 34”...
View attachment 226979
With the weight of the truck on the front at 62psi they measure 33.75”...
View attachment 226978
This is mounted on stock power wagon wheels, and the tires have roughly 13k miles on them.
thanks. slightly more than I would have guessed. I run a bit less psi tho.
That just seems like a lot of pressure to me. I run the A/T3/W (E Rated) in a 33 (275/70R18) on my Land Cruiser. I'm about 8,100 lbs fully loaded which is not that different than most PWs on routine duty. Axle split is around 4,400 R/ 3,700 F I run 42F/44R. Even wear across the tread, good traction, good ride. Right now, the Land Cruiser is unloaded and around 7,700 lbs and I'm at 30F/32R to allow for the light snow on the roads. On trail I go down to 20F/22R as my first step and then as low as 12F/15R in more extreme conditions (i.e. deep snow, sand). Of course I have OBA so airing up is no problemo.
I know full size trucks have their stickered RCTIP based upon a max GCVWR condition, but for normal travels 58 seems really high for optimal traction. Anyone pull through a highway scale to see what their axle loads are?
I'm new to this full size truck thing... but weight is weight. Just trying to figure out the logic on an additional 10-15 lbs and how that affects fuel econ and traction.
What's the front Axle weight on your truck? At 5,000 lbs the RCTIP would be in the 40 PSIG range for a 35x12.5R17.
View attachment 227072
https://tirepsi.com/35x12-50r17-tire-pressure
Similar data from Falken's site:
View attachment 227073
https://www.falkentire.com/tires/care-safety-warranty
Again, I believe the Ram door sticker is based upon worst-case load requirements. For example, at max payload on the truck plus max trailer weight would load up the tractor axles under maximum performance conditions differently than your specific use. They only get one pressure to put on the sticker and most users don't employ an OBA strategy where they adapt pressures to their load.
The biggest risk to an OEM is tire blowout. That gets people killed and manufacturers in headlines. A la Ford Exploder from the early 2000s. Blowouts are typically due to excessive sidewall heat which is a result of under inflation. Therefore they post a number that minimizes court appearances rather than maximizes performance for your specific mission. For ideal pressures I would consult a chart showing the specific pressures for your axle load. I'm continuously adjusting tire pressures based upon traction needs, air temp, etc.
Though I'm all ears if emperical data or other logic indicates otherwise...
View attachment 227071
That might just be the most informative data about tire size/pressure/load.
I always found the 37'' run better at 35-40 lbs. Now I know it's right!
I set my 35" at 36 PSI cold. So also between 35-40 PSI. They run even.
However, it's not that simple.
My tires were set at 40 degrees Fahrenheit in Woodland Park, Colorado (Altitude of 8,500').
Both altitude (atmospheric pressure) and outside temperature will change the tire PSI. If I drive my truck to the beach (sea level) and it's 80 degrees, my cold tire PSI will increase to 43 PSI. The altitude dropped by 8,500 feet and the outside temperature increased by 40 degrees Fahrenheit.
Atmospheric pressure...
Altitude (ft.) Air Pressure (psi)
Sea Level 14.7
1,000 14.2
2,000 13.7
3,000 13.2
4,000 12.7
5,000 12.2
6,000 11.7
7,000 11.3
8,000 10.9
9,000 10.5
10,000 10.1
Here's the math. So at 8,500 feet a 10.7 PSI atmospheric pressure would increase to 14.7 at sea level or by 3. My 36 psi tire setting would be around 39 PSI at sea level.
Also, for every 10 degree increase in air temperature a tire pressure will increase by approximately 1 PSI. A 40 Fahrenheit higher temperature change at sea level would equate to around 4 PSI more at 80 degrees.
36 + 3 + 4 = 43 PSI
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=167
Cool maths, feeling in high school again
Do you have the live tire pressure in dash?
It is so practical.
Just last week, temps varied from -15C to +20C ( 5F to 70F )
It's fun to see tire run from 34 PSI in the morning to 42 in the afternoon ( tires heats up from rolling )
Cheers to playing with pressure
Since I started this post guess I will go ahead and provide an update on the tires. Have about 6,000 miles on them.
- Still ride smooth.....took very little weight to balance
- Good wet weather traction, winter is coming up so will see how they do as last winter we had very little snow or ice
- Passenger front tire started cupping pretty quick, and the tires got a lot noisier. Later found out the shock was bad (started leaking badly) which will cause the tires to cup and therefore get noisy. Have since replaced the front shocks and rotated the tires and they are wearing good now.
- You can still hear them on the freeway but not bad, actually toned back down after rotating and replacing the shocks. My super picky wife has never mentioned the tire noise, but also keep in mind the half worn Duratracs made noise too.
- Some rock/mud rash on the treads after play sessions.....was climbing muddy hills bouncing off the rev limiter with the truck barely moving but the speedo showing 25 mph.
Forgot to mention tire pressure. These are E-rated/10 ply tires with a 65 psi max pressure. I'm currently running 45 psi front and 35 psi rear. This last weekend I did a 9 hour round trip hauling a 16' tandem axle trailer with a SxS and dirt bike on it along with an ARE bed shell and several hundred pounds of gear in the bed. Speeds up to 75 mph. No issues at those pressures.Since I started this post guess I will go ahead and provide an update on the tires. Have about 6,000 miles on them.
- Still ride smooth.....took very little weight to balance
- Good wet weather traction, winter is coming up so will see how they do as last winter we had very little snow or ice
- Passenger front tire started cupping pretty quick, and the tires got a lot noisier. Later found out the shock was bad (started leaking badly) which will cause the tires to cup and therefore get noisy. Have since replaced the front shocks and rotated the tires and they are wearing good now.
- You can still hear them on the freeway but not bad, actually toned back down after rotating and replacing the shocks. My super picky wife has never mentioned the tire noise, but also keep in mind the half worn Duratracs made noise too.
- Some rock/mud rash on the treads after play sessions.....was climbing muddy hills bouncing off the rev limiter with the truck barely moving but the speedo showing 25 mph.
Since I started this post guess I will go ahead and provide an update on the tires. Have about 6,000 miles on them.
- Still ride smooth.....took very little weight to balance
- Good wet weather traction, winter is coming up so will see how they do as last winter we had very little snow or ice
- Passenger front tire started cupping pretty quick, and the tires got a lot noisier. Later found out the shock was bad (started leaking badly) which will cause the tires to cup and therefore get noisy. Have since replaced the front shocks and rotated the tires and they are wearing good now.
- You can still hear them on the freeway but not bad, actually toned back down after rotating and replacing the shocks. My super picky wife has never mentioned the tire noise, but also keep in mind the half worn Duratracs made noise too.
- Some rock/mud rash on the treads after play sessions.....was climbing muddy hills bouncing off the rev limiter with the truck barely moving but the speedo showing 25 mph.