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Air bag and tire pressure


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#21 billharr

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Posted 19 December 2017 - 09:06 PM

I would recomend that you separate the bags first.

that will probably make the biggest difference. 

They should never be hooked together, because as air is pushed out of one it gets pushed into the other magnifying the effect. 

This and raise the tire pressure. I have a 2005 Tundra, E tires, and Hellwig sway bar. Run 70 psi on the tires and 40 psi and 45 psi on the bags, cabinet side higher. 

 

Running 40 psi on a tire rated for 80 psi will cause side wall flex and HEAT. Heat will cause tire failure.  10 ply tires will build much more heat than a 1 or two ply radial car tire. 


Edited by billharr, 20 December 2017 - 02:53 AM.

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#22 Vic Harder

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Posted 20 December 2017 - 12:31 AM

This and raise the tire pressure. I have a 2005 Tundra, E tires, and Hellwig sway bar. Run 70 psi on the tires and 40 psi and 45 psi on the bags, cabinet side higher. 

 

Running 60 psi on a tire rated for 80 psi will cause side wall flex and HEAT. Heat will cause tire failure.  10 ply tires will build much more heat than a 1 or two ply radial car tire. 

 

Bill, I'm not sure about that.  My E rated tires are max 80 psi as well, and I run them at 60F, 55R (front of the truck is still heavier than the rear, even with the camper mounted!).  This is based on contact patch shape and even contact all the way across the tires.

 

Vic


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#23 billharr

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Posted 20 December 2017 - 02:55 AM

Bill, I'm not sure about that.  My E rated tires are max 80 psi as well, and I run them at 60F, 55R (front of the truck is still heavier than the rear, even with the camper mounted!).  This is based on contact patch shape and even contact all the way across the tires.

 

Vic

 

Vic I had a typo (corrected). OP said he was running 40 psi (1/2 of rated pressure) which might cause heat at speed. 


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#24 rando

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Posted 20 December 2017 - 04:21 AM

This and raise the tire pressure. I have a 2005 Tundra, E tires, and Hellwig sway bar. Run 70 psi on the tires and 40 psi and 45 psi on the bags, cabinet side higher. 

 

Running 40 psi on a tire rated for 80 psi will cause side wall flex and HEAT. Heat will cause tire failure.  10 ply tires will build much more heat than a 1 or two ply radial car tire. 

 

Just to be clear - what you are calling the 'rated pressure' is actually the maximum pressure for the tire.   If you are running at the max load for the tire, you would want to inflate to this pressure, however you are not running at the maximum load so you don't want to be inflated to the maximum pressure as it will cause uneven wear and a harsh ride. 

 

 I am assuming these are not the stock tires for your Tundra, so figuring out the correct inflation pressure is not entirely straight forward - but Vic's advice on figuring out the correct pressure based on contact patch is good advice.   Another way to calculate the correct pressure is to use a load/inflation table such as this one from Toyo:

https://toyo-arhxo0v...es_20170203.pdf

 

This will give you an idea of what your pressure should be based on the tire size/rating and the weight of your truck. 


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#25 pvstoy

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Posted 20 December 2017 - 04:32 AM

Find a clean flat surface that is straight.  Place chalk line across the tread on all 4 tires.  Drive straight forward a short distance and stop.  Look at the chalk and see where it is wearing off the tread.  Wearing off middle than over inflated.  Wearing off edges than under.  Adjust tire pressure until you see a even wear across the tread.  Now you have a good contact patch.  Should do this when loaded and watch the tire temperature as you could be plus or minus with PSI.  Check pressure when cold and note this as your cold tire pressure for your new tire size/type/rating as a starting point and adjust as needed.  Just another method...


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#26 rando

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Posted 20 December 2017 - 04:33 AM

To give a quick example of this - my Tacoma has a GVWR of 5600lb.  Let's assume a worst case where I am over this by 1400lb, giving a total weight of 7000lb, 60% of which is on the rear axel.     This means each rear tire has a load of 7000*.6*.5 = 2100lb.   I have LT235/85R16 tires.   Based on the load tables, I need to run a pressure of at least 50PSI for this worst case load, which would give me 2205 lb of load per tire.    This means a load range 'C' or above tire.   I am significantly under 7000lb and I usually run 50 - 55 PSI in the rear tires which gives a nice flat contact patch and a reasonable ride quality.   But it is nice to verify that the my pressure agrees with the load tables. 


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#27 Squatch

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Posted 20 December 2017 - 07:04 AM

Best way to do this is to get your rig weighed. Total weight and each axle. Local feed store did mine. Contact your tire maker and give them the tires and size you are running. And then give them the axle weights and a description of the truck and camper. Ask them what pressure to run.

 

I did that with the Cooper STMAXX E rated tires on my '06 Tundra. For my load Cooper recommended 45+ front and 55 rear. I've been running that for 10k miles now and all is good. Tires are quieter on the road as well. I feel them at gas stops on long trips. All seem the same slightly warm temp. Even on hot days. Bulge is the same in all 4 corners as well.

 

You have a bigger truck and camper than mine.

 

For the airbags I measured the truck at all 4 wheel wells to the ground. I did this when truck was empty and no camper. Normal ride height. I then loaded the camper and set the airbags to come up to this normal level. About 2+" in my case. Between 28-30 psi in the airbags depending on load. It drives just like empty only heavier.


Edited by Squatch, 20 December 2017 - 07:05 AM.

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#28 pollux

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Posted 20 December 2017 - 07:16 AM

Rando: will this Old Man Emu D29XL Leaf Spring fits 2016 Tacoma 4x4?


Edited by pollux, 20 December 2017 - 07:16 AM.

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#29 rando

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Posted 20 December 2017 - 03:03 PM

Rando: will this Old Man Emu D29XL Leaf Spring fits 2016 Tacoma 4x4?

Yes, if you already have a Old Man Emu CS047 leaf spring pack.   This is an extra OME leaf designed to work with OME packs only, you can't add it to the stock Toyota leaf pack. 


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#30 Ronin

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Posted 20 December 2017 - 03:47 PM

On my '14 Tundra/Hawk rig I'm running 70 psi rear, 60 psi front on E rated tires. My Firestone Ride Rites are at 30 psi. My local tire pro says running at 40 lbs with a load will overheat the tires. On a recent trip total weight for my Tundra, Hawk, supplies, and myself was 7920 lbs. 

Rando, thanks for the load/inflation table - one of these days I'm going to work mine out.


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