Tundra, Norweld and Fleet Camper 8280 lbs

[JiminMaine]

We had decent weather this past week here in Maine and decided to have the truck weighed. The Cat scales read 8280 lbs with 3/4 tank of petrol. This includes two adults with absolutely nothing else in the truck or camper. Slightly alarmed at first, the Tundra has been built to take this weight.
I am finding it difficult to find a suitable tyre pressure. I attempted the max E rating when cold (80psi) though the ride was unbearably harsh. I noticed the camper juddering several times. Has any member with a similar build/setup found a comfortable tyre pressure?

 

[Taku]

Hmm, actually not sure what our combo weighs, but it is a 21 Tundra long bed with an ATC Cougar camper shell on it I built out. Likely lighter than your setup. We run 50# in the front and 55# in the back with Cooper Discover tires and am just about ready to replace them at 53K miles (they have a few thousand left in them but bad roads with sharp rocks are just around the corner). I do deflate them to about #25 when we be on washboard or rough roads for a long stretch.

 

[JiminMaine]

Thanks! I tried 50, 55, 60 front and 55, 60, 65 rear. Etc
Once the truck is ready to hit the road we will be close to 9000 lbs. A member suggested the calk test, which I will do once the salt is off the roads here. In addition I have read all the tyre related posted here on WTW.

 

[Vic Harder]

Chalk test, or an inexpensive pyrometer. Puma/Grandby with lots of gear, full size diesel truck, canoe on top, etc... I run 60 psi front and rear.

 

[jiminruskin]

I had a tundra with an AT Summit on it with Cooper 285/75R18 E rated tires. My truck loaded with lots of gear was very similar to your weight. Not knowing what tires you have I can tell you my tires were rated at 4080#'s at 80 PSI, doing the math those tires are capable of carrying over 12,000 pounds. You have to bring the pressures way down, I used to run mine between 35-40 PSI for a decent ride.

Using a load to pressure chart assuming you had similar rating on your tires you could use the chart and see that your cat scale says you have 1950#'s on each wheel in the front and 2190 #'s on the rear (give or take a little). This chart shows that you could be around 35-40 psi. Keeping in mind the tire pressure will go up @5-8 psi after they get hot. This chart is for Toyo tires but can be used for most tires. This should be a good starting point and I will bet it will agree pretty close with a chalk test.

https://www.toyotires.com/media/pxcjubjs/application_of_load_inflation_tables_20200723.pdf

 

[JiminMaine]

Jim, I truly appreciate you taking the time to share a thoughtful response. Also to the members who have reached out privately, thank you!
I too have the same tyres as you. I will try the 35 45 cold test later on today. When we picked up the camper in December all four wheels were at 35psi and the ride was incredibly comfortable. I completely underestimated the factual weight of the camper and as a result went down the rabbit hole. Thanks for the reminder of how much weight the actual tyres are rated for.

 

[Starbrightsteve]

We had decent weather this past week here in Maine and decided to have the truck weighed. The Cat scales read 8280 lbs with 3/4 tank of petrol. This includes two adults with absolutely nothing else in the truck or camper. Slightly alarmed at first, the Tundra has been built to take this weight.
I am finding it difficult to find a suitable tyre pressure. I attempted the max E rating when cold (80psi) though the ride was unbearably harsh. I noticed the camper juddering several times. Has any member with a similar build/setup found a comfortable tyre pressure?

Your statement that”the Tundra has been built to take this weight” has me puzzled. Now I know that Toyota makes excellent vehicles. I don’t know what Toyota listed as your payload but I know Tundras don’t have 3500 or 4000 lb payloads. If Toyota built the truck to handle the weight you loaded onto it, why don’t they say so or call it a 3/4 or one ton pickup?

 

[JiminMaine]

It's a great question. However, this has been covered for years on various websites. Possibly here, but certainly Expedition portal. On a stock Tundra you are limited to what the engineer's have designed. As with many similar builds to mine, this Tundra is no longer a stock vehicle. I intend to share a complete build post here on WTW once it's finished. Still have the truck interior to address and a special trip to Woodland, Ca before that happens.