What is the optimum size tire for a Expo Trailer...

[Metal Twister]

Ok, This may be a very basic question but I just dont know... Is there any advantage or disadvantage pulling an off road trailer with taller tires? Say a 38" tire opposed to a 13" tire? And the same question as far as the tire width? Seems all the military trailers used fairly tall tires. Was that to match the tow vehicle or some other reason?

 

[slimtwo]

For me, when I get to building my trailer, I'm going with the same size that's on my Jeep, 33"x 1250 x 15's. Most people (me included) as near as I can tell, size their trailer tire to match their rig, I would guess cause the spare goes both ways. That’s just my opinion.

 

[oz97tj]

I've been debating this myself. Part of me wants to mount some 35s and run the same tire and wheel as my JK. However, those tires and wheels are also expensive and fairly heavy.

The trailer axle isn't nearly as large as the axles under the tow rig and therefore you don't need as much tire to have the same amount of clearance. I haven't done any measuring yet, but I'd bet I could build a trailer with 30 or 31 inch tires and have just as much ground clearance under the axle as I do with my 35s on my Jeep. To me, having similar amounts of clearance is important. If my JK can clear it, I want my trailer to clear it.

With that said, I want my tires to be only as tall as need be so I'm not pulling around more weight than needed. And saving money in the process. Not to mention with the trailer having a lower center of gravity it would be less likely to tip.

Keep in mind, for me, I don't intend on traveling across Africa with it. I'm just looking for shorter trips in relatively rural areas. Yes, I will have to carry another spare for the trailer, but I think it would work better for my needs.

 

[Toolman]

In accordance to weight.. you have to factor in the weight of the spare as well. I just designed a trailer with Rick from offroadtrailerz.com and I used the same size tires and rims that match my Jeep. Yes they were more expensive but I found "barely used" matching tires which are now discontinued in the size necessary 37 12.50 15 MTR..after finding matching rims the price was $150 more than if I bought 3 new rims with new tires. After much contemplation and many discussions with Rick I went with a 42" X 57" X 22" box with a long tongue to accommodate CT70 trail bike across the front overall it will be a 9 foot trailer from tongue to tail lights. I did exactly what Frenchie XJ suggests which is to lay out all of your gear and measure it. This trailer will suffice my weekend warrior needs. No lid as the RTT will provide coverage from weather and keep gear out of eye sight.. no lid equals less weight. We figure with this set up I should have 23 1/2 " of ground clearance, room for a 25 gallon water tank with two batteries with H20 heater and 12v pump and all my gear. As far as a tippy trailer you can limit your rotation by adding a stopper to the multi axis hitch.
I guess after all my banter my point is You should make it "right" for you.

 

[elmo_4_vt]

I matched the tires on my trailer to my truck. I still carry, or at least have the ability to carry a spare on the trailer, but it's a small, light spare, in case I need to take one of the trailer tires for the truck (think mini tire, almost like a donut, because I don't care if the trailer is tilted). Larger tires also give you some additional benefits. You hubs don't have to spin as fast, meaning that your bearings will be a little happier. My cousin has seized 3-4 bearings on his small utility trailer that uses 13" tires. If you do the math, those spin so much faster doing 60-70 mph down the highway and I think that has to contribute to his problems because of heat buildup. Also, off road, the larger tire you have, the easier time you'll have pulling over obstacles. The closer to the midpoint of the tire an obstacle hits, the more resistance you have going over it. Think of a car trying to go over a 1" lip in the road vs. a curb.

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[highlandercj-7]

If all your worried about is ground clearence then, like you said is fine. 30-31's would net more than your rig, assuming your rigs diff hangs down 6" below axle center line. So the trailer tires can be 10.5" shorter than the rig to net the same clearence. Assuming a 3" trailer axle tube.
Most folks want the trailer tires to match there rigs for interchangability (or looks) So though it's not needed, it's a nicity. The end product is the trailer has way more clearence than the rig.

 

[java]

i like having two extra spares, id be much happier ditching the trailer than my truck somewhere....

 

[Metal Twister]

So it looks like the same height tire as the tow vehicle is preferred. And wider for flotation or narrower for weight?

 

[roadkill]

I think I'd go narrower for better performance (easier to pull and better fuel mileage from the decreased rolling resistance) on the road. I doubt a wide tire will be noticable offroad on a trailer. I've been thinking of going to 33 10.50s ATs on my trailer vs the 33 12.50s MTs I have now just for this reason

 

[ntsqd]

My TrailBlazer trailer came to me with 33-12.50 tires on it. Oddly those are the largest tires in my whole fleet. I will be moving the trailer to 30-9.50's as soon as I find a suitable rim.

The P-PO had everything setup to use the same tire size with the idea that he could use the spare anywhere. I'd rather carry a second spare as towing the trailer just increased my flats vulnerability by half again. If I'm carrying a spare on the trailer then it cuts into the payload of the trailer, so why make it any bigger than it needs to be?

 

[elmo_4_vt]

... If I'm carrying a spare on the trailer then it cuts into the payload of the trailer, so why make it any bigger than it needs to be?

But there is nothing saying that you have to carry a full size spare on the trailer. I was saying that I carry a donut'esc style spare for the trailer. If I go through the truck spare and need another, who cares if the trailer is a bit lopsided.

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[CA-RJ]

I don't understand how you guys are running the same sized tires on your trailer as your tow rig. I run 33's on the 4Runner and 235/75/15's on my trailer and my trailer sits level.

 

[Toolman]

If you've ever torn a tire beyond repair in the first two miles of a trail and you're puckered for two more days knowing that no else has a spare for you, you might know where I'm coming from.. I like the idea of a donut spare for the trailer.. I would rather drive it tilted all the way home than try find another tire somewhere... also a plug kit is very handy.. put the plugged tire on the trailer and good tire on the rig.

 

[ntsqd]

I wouldn't be concerned with the lopsidedness from using a donut spare either. What I would be concerned with is the added wear and tear on the trailer and just how far the spare will last. A donut tire isn't going to have near the impact absorption ability that a full sized tire will. Keeping it alive could significantly slow the pace.

I prefer to keep the trailer spare the same size as the trailer tires. I just don't see putting a 1500-2000 lbs gross weight trailer on 200 lbs. worth of 35" tall tires.

As an example of how silly the 33-12.50's are on my TB, I once towed the trailer nearly 400 miles on a tire that had 5 psi in it. I just completely spaced checking the tire pressure before leaving town. It did not get hot (I checked twice for tire & bearing heat along the way), it did not bulge significantly (which is why it's low pressure was a surprise!), it didn't even behave poorly on the road. It was only when I made the rounds the next morning that I found it low. It does leak through the valve stem, but not overnight.

 

[Robert Bills]

I think I'd go narrower for better performance

I prefer to keep the trailer spare the same size as the trailer tires.

I agree and I agree.

My offroad trailer experience dates back to the mid 1960's, when my dad bought 7 wide wheels and Armstrong 11x15 tires from ******** Cepek when Cepek was just starting his offroad tire business in his garage. (Matched larger-than-stock wheels and tires on jeep and trailer is nothing new. The rationale then was the same - looks cool to have a matched set and one less spare.)


I didn't match my current trailer tires to the 35x12.50x15 BFG MT tires on my jeep because:

1. 35" tires are big, heavy and expensive. MT tires are appropriate for a drive axle; unnecessary on a towed axle. They add nothing to the trailer's ability to be pulled across any reasonable obstacle and make the trailer more difficult to maneauver by hand. Installing them on the trailer would also force me to modify the suspension and replace the fenders.

2. I remember two occasions, once deep in Baja and once in the dunes at Pismo Beach, when one spare shared between jeep and trailer wasn't enough. (Reason alone to abandon the concept forever.)

My solution:

I wanted the tallest tire that would fit the width of the trailer fenders using the stock suspension. That measured 31" However, every commonly available 31" offroad tire is a 10.50, too wide with a stock offset wheel because it would rub both on the trailer tub and the fender edges.

I went with military 7:00x15 NDCC tires on the trailer. Nearly 31" tall and 7.5" wide mounted. For now, I carry extra tubes and tire tools and can use the jeep's 33x9.50 spare in a pinch. I have an identical trailer spare ready to be mounted "just as soon as I get around to making the bracket for it."

You may notice that my jeep spare is 33x9.50 but it's tires are 35x12.50. (Largest spare that would fit my swing-away rack.) Although the spare is 2" smaller in diameter, it is a true offroad tire and not a "donut." It will get me off the trail and far enough down the road to get a repair or replacement without worries that it might not be up to the terrain or distance.

I am sold on the idea that jeep and trailer should each carry its own spare, and that the spare on each should be identical in size, if possible, to the tire it is intended to replace. However, it is not always possible. In such an event, my preference is a real tire very close in size.