Maximum towing speed

[Robert Ley]

My winter project is to build my first TD trailer. I have some plans and am in the process of getting the trailer frame. I have pretty much settled on the 5x8 Ironton trailer from Northern Tool. It has 12inch tires and my question is, how fast can I safely tow this trailer after I have built the Tear Drop? I will be using a Subaru Forester and would just like to keep up with traffic, say 65-70 mph. I have a 14 ft Wells Cargo enclosed trailer that I have been towing for years albeit not with the Subaru, so I am an experienced driver but not with such a small trailer. What are your experiences towing a TD such as mine and is the 5x8 Ironton trailer a good choice?

This is my first post, but probably not my last.
Thanks in advance for any help and this is a great source of info
Robert

[DrewsBrews]

Honestly there is no magic number. Usually the lower the weight the safer it is since the vehicle weight has more influence, though stability has more to do with the % of the trailer weight as tongue weight and length of tongue. You'll just have to see what you are comfortable with once it is built and experienced pulling it around in various conditions. But the speeds you want aren't out of the question with an appropriate setup.

[Shadow Catcher]

Are in part related to tire speed ratings. ST tires are rated and supposedly tested to 65 MPH. I went with Micheline passenger car tires rated at 85MPH.
The tires were rated for 1600# each.

[elcam84]

Like drewsbrews mentioned the tires have allot to do with it. Get the highest speed rated you can. The other issue is diameter. The smaller the tire the faster that bearing spins and the more it heats up. I would suggest getting new high quality bearings and synthetic grease for you trailer as I am always weary about small kit trailer bearings.
Now the 12" rim that most small trailers use are also used on jet ski trailers. Have had singles and double trailers with them and they are perfectly happy running 80+ mph all day.

Speed is an issue for me as well as the sped limits are 70 to 80 here depending on where you are so 80+ is not uncommon especially when going to a camp spot/lake which is always a long ways off here.

[Gladtobehere]

I would also like to point out that fuel efficiency should also be considered in the speed equation. In my experience most cars seem to be at max efficiency around 55mph and the efficiency falls off quickly above that speed. (Whether towing a very aerodynamic teardrop or nothing at all.) Personally I try to keep my towing speeds under 65mph.

Low fuel prices are no excuse to ignore our climate and our debt to the future.

[Socal Tom]

In California, legally trailers can't go over 55. I believe moist states have vspeed limits for towing. That being said, read the sidewall of the tire, it may have a speed limit.
Tom

[elcam84]

I have found that fuel efficiency at higher speeds doesn't really change much in fact many of my vehicles get their best mileage around 70 to 75. However LOML'S pt cruiser stick gets awful mileage (max 20) no matter how you drive it. Needs another gear... (the automatics got better fuel mileage) My 90s cars got much better fuel mileage than most current cars as well. Lesabre got 36 mpg on trips at 70+.
Towing a trailer does make a difference though I have found that increased speed still isn't really detrimental to mileage unless it's windy. Keeping up with traffic and not trying to aggregate other drivers on the road or cause an accident is more important than a tiny amount of fuel. Those that live in Great Brittan can attest to that as their trailers have to go excruciatingly slow on the road because their tow vehicles can't handle higher speeds safely with the extra weight. They gut stuck behind a slow trailer for miles.

[daveesl77]

If I'm towing on a two lane road, I have a rule of thumb that when a maximum of 5 vehicles have stacked up behind me or if the road is real curvy or has lots of traffic and very hard to pass on, I'll find a safe spot to pull over and let them go by. I kind of stopped using interstates if at all possible a few years back simply because they are boring. I don't care if it takes me another hour or three to get somewhere, I want to see stuff. Now, if I need to get to a place in a more reasonable time, then yep, back on the freeways.

There are so many variables that affect mileage, big ones are 1) speed, followed closely by 2) tow frontal area and shape. A flat front creates far more drag than a curve. 3) is the rear tow shape, once again flat creates more drag and 5) is the height/width of the trailer vs the height/width of the tow vehicle. Weight, while an effect, doesn't come much into play believe it or not. Once in motion, tends to stay in motion.

dave

[Robert Ley]

Thank you all for your excellent and timely responses to my quarry. I am looking forward to traveling down the road with my new TD and I'm sure I will have more questions during the build.

[rowerwet]

For me, maximum towing speed is what I can safely panic stop and do avoidance lane changes from without losing control. Once loaded, I find an empty road and practice these at higher and higher speeds to get a feel for it, then start out slower than traffic until I get comfortable with how it is flowing.

[Tomterrific]

I built my trailer light so a small engine could pull it. Unfortunately it also is a motorcycle hauler so the rear is square back. This makes a bunch more air drag than I thought. The weight is negligable but drag goes up the square of speed. Twice the speed is four times the drag.

Wife and I took a trip down I-75. I had wiped some grease on the bearings before the trip but I didn't bother to clean them first. I worried about the old tires and bearings so I stopped and put my hand on the tires and hubs. They were only slightly warm even towing at a steady 70 or above so I stopped worrying. I still kept checking every stop. Mileage suffered from the air drag though.

T

[Socal Tom]

SLightly off topic, but here is a good video on how to pack a wheel bearing properly.
https://www.youtube.com/watch?v=JXYvJv-zWlw
Tom

[Tomterrific]

Hangs head in shame. I was a mechanic in the 70's so I know how to do a perfect job, I just short cutted. I had packed them maybe 2000 miles ago so just did a quick check.

T

[elcam84]

SLightly off topic, but here is a good video on how to pack a wheel bearing properly.
https://www.youtube.com/watch?v=JXYvJv-zWlw
Tom

I remember packing bearings that way. When I was an ase master I bought a lisle bearing packer. Insert bearing step on and done in seconds and cleanly. Still usable now but the plastic is showing it's age. Good synthetic grease is recommended as well.

[Socal Tom]

Hangs head in shame. I was a mechanic in the 70's so I know how to do a perfect job, I just short cutted. I had packed them maybe 2000 miles ago so just did a quick check.

T

I had a friend that thought wiping the bearing was enough. Personally I put a bunch in the hub too , especially if its a boat trailer that will see time under water.
Tom