Tire Pressure

jkjenn

The T@b owner's manual indicates that tire pressure for the stock tires should be about 35 lbs. I upgraded to the Outback tires. Any reason I should use a different PSI than 35 lbs? Both indicate PSI of 50 lbs on the tires, themselves.  

Ratkity

jkjenn said:

The T@b owner's manual indicates that tire pressure for the stock tires should be about 35 lbs. I upgraded to the Outback tires. Any reason I should use a different PSI than 35 lbs? Both indicate PSI of 50 lbs on the tires, themselves.  

At max pressure, a light trailer bounces more than a pogo stick. Keep to the owner's manual recommendation. It'll extend the life of your tires and make controlling the trailer on questionable roads easier.

jkjenn

Ratkity said:

 

At max pressure, a light trailer bounces more than a pogo stick. Keep to the owner's manual recommendation. It'll extend the life of your tires and make controlling the trailer on questionable roads easier.

Thanks. That is what I was thinking. Also, reduces the likelihood of delimitation, from what I understand.

RZRBUG

The 50 lb. is for maximum trailer load, I think.  If you have your trailer loaded to its max and run 35 lb., the tires may not handle the load.  I have found in my research that there is much disagreement on this subject.

I can give you my experience.  I ran my original tires at 35 lb. the first year.  The tires wore and pitted on the outside, indicating they were under inflated.  I recently put new tires (changed to radials) on after just over 3,000 miles because I didn't feel safe with them.  The new tires have 45 lb.  I have only made one trip with them, but they seem to be doing fine.  I tend to load it a little heavy.  I will keep a check on them and if they start to wear uneven in the center, I will deflate a little.

BigGrover

I cannot find anything in my 400 manual about recommended tire pressure, am I overlooking it?  My Jayco had a sticker next to the wheel well with that info.

Verna

@BigGrover, look at the driver’s side of your T@B 400 and there is a tag near the front, on the side of the 400. It has the maximum tire pressure printed on the label. My T@B 320 says 50 lbs, the tire says 50 lbs and I run my tires between 42 to 45 psi, but normally 45 psi. This gives me less bounce than 50 psi, and a smoother ride. 

BigGrover

Thanks Verna, will look tomorrow.

BrianZ

45 is what I  aim for too & works fine.

4ncar

The outback tires are radials, where as the the regular 320s are bias ply. The inflation amounts differ due to the different tire construction.  Underinflating any tire is asking for trouble.  My outback is inflated to 50 lbs before I leave(cold pressure). Ymmv...literally, in this case...

Tabaz

My factory Outback tires are General Grabber ATZ 27x8.50R14LT, Load Range "C."  I've religiously kept them at 45 lbs. pressure for highway driving, but always felt the need to deflate them over washboard roads.  After some research, it appears these are Light Truck tires (not trailer-specific tires).  The "C" rating means two tires can handle a 3,640 pound load.  I plan on deflating them down to 25 psi over the next washboard road to see if I can gain some speed.  At 45 psi, I can't go more than 1 or 2 mph without significant bouncing of the trailer.  Any thoughts from those knowledgeable would be appreciated.

jkjenn

Tabaz said:

My factory Outback tires are General Grabber ATZ 27x8.50R14LT, Load Range "C."  I've religiously kept them at 45 lbs. pressure for highway driving, but always felt the need to deflate them over washboard roads.  After some research, it appears these are Light Truck tires (not trailer-specific tires).  The "C" rating means two tires can handle a 3,640 pound load.  I plan on deflating them down to 25 psi over the next washboard road to see if I can gain some speed.  At 45 psi, I can't go more than 1 or 2 mph without significant bouncing of the trailer.  Any thoughts from those knowledgeable would be appreciated.

Let me know. I run mine at 45lbs, too, and it seems like deflating them for the washboard roads will help. I will be taking the T@b down one in a couple of weeks and it might be worth trying. I travel with a good air compressor and tire deflator.

seajeeper

You should have no problem deflating them as long as you are travelling at low speed.  I regularly deflate my Jeep tires (Radials) to under 10 psi for the entire day while 4-wheeling.  But you have to air them back up if you plan on going faster than about 10mph.  Bias ply tires are especially susceptible to overheating if under-inflated and run at higher speeds.  When I ran bias ply tires on the Jeep, I aired down to about 5psi....

FYI, my regular 320 tires are radials (2016)

db_cooper

Tabaz said:

My factory Outback tires are General Grabber ATZ 27x8.50R14LT, Load Range "C."  I've religiously kept them at 45 lbs. pressure for highway driving, but always felt the need to deflate them over washboard roads.  After some research, it appears these are Light Truck tires (not trailer-specific tires).  The "C" rating means two tires can handle a 3,640 pound load.  I plan on deflating them down to 25 psi over the next washboard road to see if I can gain some speed.  At 45 psi, I can't go more than 1 or 2 mph without significant bouncing of the trailer.  Any thoughts from those knowledgeable would be appreciated.

We still have our original Grabbers, and have run them at 35psi ever since we got it,  same as the light truck tires as our tow vehicle.  Much less bounce, and works well on washboard.  I don't think you need to go down to 25 lbs on washboard.

I drive up to 70mph on the freeway, and always touch the bearings and tires, and they've never been more than slightly warm on a hot day. 

We took our first trip at 50 psi and it was miserable how hard the trailer bounced.  Got about 5000 miles on it now and there's no noticeable wear.  I think 35psi is the sweet spot for these particular tires. 

Ratkity

As long as they are light truck tires, you can safely deflate them. Trailer tires have stiffer sidewalls to accommodate the vertical load. Trailer tires should be filled to within 5 lbs of their max rating.  Under-inflating them could cause a side wall blow-out. The unfortunate part about owning a small trailer or canned ham is that a tire blow-out can take out more than just the tire. It can damage the upper part of the wheel well.

I know my little bitty teardrop bounced from here to kingdom come with the tires at the proper pressure, but the solution was to put a little more weight over the axle, not under-inflate the tires.

ericnliz

AND...make sure you set the tire pressure COLD. Before you drive on them. Pressure INCREASES with running the tires under normal circumstances. 40 to 45 Psi cold is where I set my original set, depending on trailer load. At 50 PSI it bounces WAY too much. They are wearing perfectly, hardly any noticeable wear.

Tabaz

Thanks for all the comments!  A few other items I learned: Avoid sharp turns with the tires deflated (best to go in a straight line).  Carry a ratcheting strap in case the bead comes off the rim (my Grabbers are tubeless, so yes).  Wondering if I need to air-up the tires upon arriving at the campsite.  The tires may still be warm from the trip (asphalt and washboard)?  Not sure I'd want to camp for an extended time with the deflated trailer tires.

jkjenn

db_cooper said:

Tabaz said:

My factory Outback tires are General Grabber ATZ 27x8.50R14LT, Load Range "C."  I've religiously kept them at 45 lbs. pressure for highway driving, but always felt the need to deflate them over washboard roads.  After some research, it appears these are Light Truck tires (not trailer-specific tires).  The "C" rating means two tires can handle a 3,640 pound load.  I plan on deflating them down to 25 psi over the next washboard road to see if I can gain some speed.  At 45 psi, I can't go more than 1 or 2 mph without significant bouncing of the trailer.  Any thoughts from those knowledgeable would be appreciated.

We still have our original Grabbers, and have run them at 35psi ever since we got it,  same as the light truck tires as our tow vehicle.  Much less bounce, and works well on washboard.  I don't think you need to go down to 25 lbs on washboard.

I drive up to 70mph on the freeway, and always touch the bearings and tires, and they've never been more than slightly warm on a hot day. 

We took our first trip at 50 psi and it was miserable how hard the trailer bounced.  Got about 5000 miles on it now and there's no noticeable wear.  I think 35psi is the sweet spot for these particular tires. 

Yeah, I would probably just drop to about 35lbs.

Tabaz

DB - thanks for the info.  I'll try them at 35 psi and see how they do on the washboards.

4ncar

I agree with deflation at low speed and rough, soft surface. But be carful not to deflate too much as popping the bead would really suck, even if you have a ratchet strap to attempt a reinflate. I would prefer the ol ether & a match trick!!

Ratkity

@4ncar, doesn't that ether + match go BOOM!?!??

4ncar

@Ratkity ah, yes! The miracle of expanding gasses!! I use this method on utility trailers & my lawn tractor tires over the years. Bungy cords & rachit straps work, but are frustrating, imho.

Tabaz

Ratkity and 4ncar - What are you guys talking about?

ericnliz

@Tabaz , it's an old trick used by farmers, loggers, & such to re-seat a tire that for whatever reason has disengaged itself from the rim, & is no longer sealed to accept air. A LITTLE squirt of ether inside the tire, a lit match tossed in & WHOOM, sealed back up. NOT something I would recommend for novices!

tabiphile

Probably quite a few folks will have trouble re-seating a tire with ratchet straps, never mind the starting ether trick. If it's not something you've done before, it may be best left to the pros... much like letting air from the tires.

If you are not 100 percent certain that you have truck tires (vs. trailer tires) running on low pressure is not a good idea. Trailer tires must be inflated to the correct pressure to prevent wear and avoid sidewall damage. If you do have truck tires and choose to let air out of them, what is the likelihood that you will forget to put air back in them before you start towing? It's probably better to slow down a bit than start fooling around with running low air pressure....if you let too much air out and damage the bead on your tire you'll be using your spare, if you have one.

4ncar

Agreed on all points.  The ether trick is not for the light hearted.  I have done it a thousand times (singeing my leg hair a few times to boot with the “whoosh of flame! Lol), and running low tire pressures on my off road jeep for years. But as said elsewhere reinflating to road pressure is a must prior to attaining highway speeds.

JohnDanielsCPA

I’ve had my T@B for almost two years.  I’ve gone 2,300 miles with the tires at 35 psi and haven’t noticed any problems with the tires.  Seems to be a good compromise pressure for both on and off road.  The total trailer weight is less than 2,500 pounds.  If I were over 2,500 pounds, I would increase the tire pressure, depending on what the total carry weight was.  If you have ST (trailer) tires, you should run them at max pressure.  If you have LT (light truck) tires, you can adjust the tire pressure to the load.