Trailer Chassis

[Alphacarina]

No doubt that quality tires are an important consideration . . . . though there are many folks here who have put many thousands of miles on the HF Chinese made tires. Revolutions aren't much of a consideration as the tires ARE inflated to 80 PSI so they don't get hot even at their rated load and the bearings are probably good to 3X or 4X the RPM's they typically run at

If you want a cushy ride, you really can't beat the 175/80-13 trailer tires. I run mine at a mere 25 pounds and they run cool as a cucumber with no bounce at all

Weight is especially important for small cars - If you prefer to use a heavy duty trailer with a 2500 to 3500 pound axle and heavy 15 inch wheels, do yourself a favor and order it with electric brakes because your goal of a little 1100 pound teardrop may well wind up weighing more than 1500 pounds, and while a small car may tow it fairly easily, it will be a handfull to get it stopped with the brakes on an econo-box . . . . especially in a panic situation

Don

[Steve F]

To put a little perspective on trailer weight etc, even with my homemade offroad frame, 15" mud tyres and 45mm thick solid axle my TD came it at 490kg which is 1078lbs.

Cheers
Steve

[brian_bp]

I think the key is appropriate hardware, whether it comes as a kit or you put it together yourself. That means 3500-lb capacity springs on a 1200 lb trailer are not a good plan, whether they come in a too-big kit, are retrofitted to a right-sized kit trailer, or are included in a full custom design; large-diameter tires don't need and shouldn't have high load range construction; etc. It also means that if the right bits for you are all different from the kit trailer, the kit isn't going to save you any money over custom building, but if most of the parts in the kit are right, it likely makes sense.

[Frog]

I certainly didn't mean to be critical when I posted the first message or argumentative with followups. I was genuinely curious and the old adage of being penny wise and pound foolish comes to mind as well as you get what you pay for.

I'm glad the HF trailers work so well.

Thanks all for answering my questions.

[Alphacarina]

I don't think anyone looks at your comments as critical or argumentative

The key thing to understand is that a teardrop trailer is basically a rigid box and only needs enough frame under it to attach an axle and a coupler - Anymore than that is basically wasted weight. Now if you wanted to tow around a 1,000 pound garden tractor, driving it up and backing it off the trailer, then a 'flimsy' HF trailer wouldn't be at the top of your list - It's probably not rigid enough to last very long doing that sort of thing and you would be much better off buying a well made (American made?) all welded trailer frame

If your teardrop floor is well designed and constructed, you could just about bolt the axle hangers and the tongue directly to the floor and forget about any more 'frame' so a minimalist frame like the HF kit is plenty good enough

Don

[Frog]

Don: I take that the cute cowgirl in the side bar is not you.

[Elumia]

I noticed some comments here about tire RPM's. I found this link which is pretty informative.

It calculates tire size and revolutions per mile for various tire sizes. Now, if you are going 60MPH that is equal to RPM. RPM would be more associated with the final tire size than the rim size. a low aspect ratio 15" tire may rotate at the same (or more) RPM as a high aspect 13" tire.

Soooo

185/80 13" goes 818 revolutions per mile (overall dia 24.65")
205/75 15" goes 744 revolutions per mile. (overall dia 27.11")

Here is the tire diameter calculator, which calculates Revolutions per mile also. note that this is the "calculated" determination of size, for specifics you would need to go tothe individual tire mfg. Tire rack's web site has that info too.
http://www.gtsparkplugs.com/TireCalculator.html

Mark

[Frog]

Thanks for the tire rpm calculator.

Way back in 1977 I bought a new Honda Civic which had fabric belted BF Goodrich radial tires on 4 bolt 12" rims. I think they were about 155/12s. I figured they were good for 20,000 - 25,000 at best. I replaced them at 44,000 miles. They still had tread but I blew the sidewalls on two of them. I'm good about tire pressure (blown sidewalls are usually from overheating an underinflated tire, but not in this case) and rotation or they wouldn't have lasted as long as they did. It was an 1,800 lb car with about 65% of the weight on the front wheels. With passengers, the fronts were carrying something like 750 lbs each. If still available in that size in a steel belted tire they would make a good 12" tire for a teardrop.

[brian_bp]

...I think they were about 155/12s....
If still available in that size in a steel belted tire they would make a good 12" tire for a teardrop.

12" car tires are essentially gone, and even in 13" there is very little selection, although 155/80R13 is still pretty common. On the other hand, 145R12 is a readily available trailer (or commercial) tires size; I agree that this 12" size (like the 155/80R13 size, in a car tire model) seems like a reasonable sizeand capacity match for many teardrop or similar trailers.

[Frog]

Brian I still believe that 13" or larger car/trailer tires would be "low pressure" tires with the same capacity as the 5.70/12 tires that run at 90 psi and would give the trailer a softer ride, particularly with leaf spring suspension. That softer ride would also be felt in the light weight tow vehicles.

I've said enough on this subject.

[brian_bp]

Brian I still believe that 13" or larger car/trailer tires would be "low pressure" tires with the same capacity as the 5.70/12 tires that run at 90 psi and would give the trailer a softer ride, particularly with leaf spring suspension. That softer ride would also be felt in the light weight tow vehicles.

I agree!

I was thinking that the comparison was to "red" trailers with 8" wheels, but I realize now that the models up around 1,180 lb capacity (e.g. 1175 Lb. Capacity 48" x 96" Heavy Duty Foldable Utility Trailer) have 4.8-12 tires... they are already at 12". The idea of wider (if not necessarily taller) but lower-pressure tires still applies; that can be a car tire or a low-load-range trailer/commercial tire.

While a 4.8-8 tire would need 60 psi for a 1180 lb trailer, there's no need to run even the stock 4.8-12 tires that high, an ST145R12 (load range C) needs only half of its 65 psi capacity, and an ordinary 155/80R13 or P155R13 would likely need substantially less than 40 psi.

Despite the practices routinely followed with trailer tires, the maximum inflation pressure for a tire is not necessarily the right inflation pressure, and while the maximum pressure of load range C 12" trailer tires can be as high as 90 psi, that's overinflation if they are only carrying half of their rated capacity. A nice feature of the ST145R12 style - as compared to the older and nearly as large 5.30-12 - is that the more broad-shouldered shape provides much higher load capacity at significantly lower pressures... it's more like a modern car tire than an antique truck or trailer tire.

[brian_bp]

...
If you want a cushy ride, you really can't beat the 175/80-13 trailer tires. I run mine at a mere 25 pounds and they run cool as a cucumber with no bounce at all...

I agree that these tires don't need much pressure to handle a trailer around 1000 lb... they can handle over 1000 lb each at only 35 psi. ST tires are not even needed in his combination of trailer weight and tire size: although 175/80-13 is not an available car tire size, 175/70R13 is, and would also have enough capacity to be run at perhaps 30 psi or less.

[Frog]

In a different string I had asked why so many used HF trailers.  Cost and availability seemed to be the main answer.  Many then modified them to eliminate the folding part, replaced the bolts with higher grade bolts or welded the frame, modified the tongue to make it stronger and replaced the 8 or 12" tires with larger tires and finally replace the screw down cuppler a positive latch type.  It makes me wonder how much is really saved in the long run when one considers it's still a made in china trailer with made in china bearing, etc.  I also don't think a better built trailer would weight that much more or cost that much more in the long run.Many have told me all you need is something failrly flimsy in effect to hold this super strong "box" and that you could almost bolt the axles to the box without a frame.

Finally aestheticaly, everyone is trying to emulate the "original" teardrops more or less.  Those early trailers used 16'' or 17" second hand automobile wheels and tires.  Probably in the range of 6.00/16.  The skinny 8" and 12" tires just don't look "right" to me.  The 5.60/15 tires and wheels on the 1970 VW (by then they had the small center bolt pattern) I owned in the 1970'a would look about right and should fit under most trailer fenders.

I'm really not trying to start a firestorm about this, it's just my opinion for whatever it's worth.

[Lou Park]

Hi Frog, I would have to agree with you, cost and convenience are the first thoughts that come to mind with the HF trailers. However if you check into the cost of the materials (and I have) that come with the HF or even northern tool trailers, it's quite a bit less money to buy these trailers and cut, stretch, shape, what ever you want to do with them. then it is to buy the materials and build yourself. If you check into it yourself, you may want to remember to look up cost for hitch connector, lights, wheels, axle and springs. Every time I add these up, it comes out to around $665 minimum. This doesn't include any welding, or drilling for bolts, cutting and scratching the back of your head. However if you find a better cost, let me in on the secret.
Lou

[Mark McD]

The Harbor Freight Heavy Duty frame is rated @1740#. I believe this is the frame that most builders use, not the 4x8 folding version, right?
My cubby, fully outfitted and wet, weighed less than 900 pounds, almost half the rated weight.
BTW- the HF HEAVY DUTY 1740# Trailer is on sale now for $349.