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Tire Pressure & S Mode while towing

7K views 31 replies 16 participants last post by  ColoradoTJ 
#1 ·
2013 CrewMax 5.7 V8 4x4
Tires: P255/70R18
5,000 Pound Trailer

1) What tire pressures do you guys use/recommend? On the door it says 32PSi, max on the tire is 48Psi.

2) I was looking through some other threads and notice some say they use the tow/haul button as well as S mode. I am curious as to why one would tow in S mode? Is it just to have more control over the shifting? I have used S mode to lock it in gear for braking purposes, but never for just towing the boat across a flat surface.

Thanks in advance!
 
#2 ·
Everyone has different thoughts on this situation, so much that it will make you cross eyed, lol. As for me I do hauling and towing and literally have used tow haul mode only once! I find it has more than enough power in s mode and I also get the control I need, going uphill in 4th I find to be perfect then I change it to 5th when adequate. So imo it's all a preference because they both get the job done
 
#3 · (Edited)
I tow a 9k lb load.

Put the shifter in 'S' mode (leave it in gear 4) and push the tow haul button when towing at all times - your owner's manual says the same thing. This will help keep your transmission from constantly hunting for gears and thus keep trans temps down, as well as activating the engine brake which will keep brake temps down, among other reasons. Let the computer do the work here rather you trying to override it.

As for tire pressures - your door plate likely calls for different pressures for the front and rear. When towing I make sure that the pressures are 2 or 3 lbs higher then what the door plate calls for which in my experience provides a better ride and control.

Probably equally important is to ensure your trailer tires are properly inflated (max psi on tire) and that you have working brakes.
 
#4 ·
I believe s mode in 4th and 5th allows full torque converter lock up. Making the climb up hills much easier. I'm not 100% on this but was told so by the master tech at my dealership. I have tried S mode and not using S mode while towing and like S mode much more. Plus in the event you need to downshift manually you can.
 
#6 ·
S mode prevents the up shifting past the selected gear and puts the transmission into a standard shift pattern vs using the adaptive shift logic. Tow haul will modify the throttle for towing and shift pattern if left in D.
 
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#7 ·
I'm new to towing, but my tires have a max psi of 50 and I set them just below that.

As far as S mode and only going to 4, my manual from '08 says to only use S when engine braking is required. So far I've just used D with tow/haul on. Guess I will have to try the S next time.
 
#8 · (Edited)
For clarification the below was taken straight from the owner's manual....


TOW/HAUL switch (6-speed models with towing package)

-Use TOW/HAUL mode when pulling a trailer or hauling a heavy load.

-Press the TOW/HAUL switch. The indicator will come on.

-Press the switch once more to cancel the mode.

-To maintain engine braking efficiency and charging system performance
when using engine braking, do not use the transmission in
D.


- Transmission shift range position must be in 4 in the S mode.

http://www.toyota.com/t3Portal/document/om/OM34491U/pdf/sec_2-1.pdf
 
#12 ·
Owners manuals seem to change year to year. My info is from the repair manual. D was causing to much shifting with 7k trailer on hilly terrain.
 
#13 ·
Same boat (no pun intended) as 97FASTech - tow/haul mode AND Sport mode locked at 5th. I tow 8K #'s roughly twice a month.

Towing 101 - lock out overdrive when towing heavy loads.
 
#15 ·
X2
 
#18 ·
Thank you everyone for taking the time to respond, I greatly appreciate it.

I am not sure I understand S mode correctly.

When I switch to S mode, it shows me the gear I am in. In my Tundra, it always shows 4, whether I do it driving, or whether I am stopped at a red light.

So when I am driving in S mode, the truck will shift from 1 to 2 to 3 to 4, and then not go above 4 unless I shift it to 5 manually. Is that correct?

However, if I am going down a hill, it will still down shift to use the engine as a brake? Or do I need to down shift manually?

I did experience my truck searching for gears last time I towed, as well as shifting into an extremely low gear(higher RPMS than necessary for sure) when going up a hill. So maybe towing in S mode will reduce or eliminate that issue. Thoughts?
 
#20 ·
It will not down shift unless your completely stopped, instead it will engine break. When you switch it into s mode it will always go into 4th as you have noticed. Try it out, when towing and getting on the freeway on ramp put it 1st from take off and you will see how well it works. The cool thing is the comp won't let you change gears unless it's safe for the trans, meaning if your at a high rpm in 4th and try to downshift into 3rd it won't let you unless your at a safe rpm to move into 3rd, and downshifting in to 1st is only used when absolutely needed and Goin 15mph or slower
 
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