"whatisthatsound" (whatisthatsound)
06/10/2019 at 20:49 • Filed to: Towing, Morgan, Morgan 3 Wheeler
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"whatisthatsound" (whatisthatsound)
06/10/2019 at 20:49 • Filed to: Towing, Morgan, Morgan 3 Wheeler | 1
| 20 |
What direction to park the Morgan in, and how to calculate CG?
I’ll take any ideas before I hit the open road. My question is simple.
Does a correct tongue weight, 10-15% of the total load, mean I am within the 60% in the front / 40% in the rear weight loading rule . Therefore my CG is correct. (Can this assumption even be made)
Morgan weighs 1300lbs, and has a 61% front / 39% rear weight bias.
Trailer weighs 1200lbs with an empty tongue weight of 125lbs
Total weight= 2500lbs total.
Loaded engine first the tongue weight goes from 125 to 500lbs, 20% total load. When backed in tongue weight is 300, 12% of total load, and within the correct range. All weights were taking with a tongue scale.
A few unknowns is where the center point of the Morgan is, and the CG of the empty trailer. Some pictures for reference.
1300lbs
1200lbs
Tongue weight is 350lbs and wheels are 12 inches from trailer axle.
Tongue weight is 500lbs and wheels are 4 feet from axle
Highlander-Datsuns are Forever
> whatisthatsound
06/10/2019 at 13:32 |
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I’ll need the distance from the trailer axle to the hitch to do a proper evaluation but really loading like you did and the relative light weight, I would be too concerned. Assuming you are towing with at least a 1/2 ton full size truck.
RamblinRover Luxury-Yacht
> whatisthatsound
06/10/2019 at 13:35 |
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60% forward of axle and 10% of total load are two different numbers. There is no direct translation from one to the other, as tongue weight
depends on
the distance from the axle to the tongue vs. the location of the c.g.
. The dynamic reality can also change depending on how long the load is vs. its height above the axle, and how that relates to tongue to axle length.
Take for example a really, really long and tall load on a short trailer. Its center of mass could be set correctly for 60/40, but you could easily be over your 10%, and it would shift to waaaay higher under braking.
Between the two, proper tongue weight is probably more important.
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whatisthatsound
> Highlander-Datsuns are Forever
06/10/2019 at 13:40 |
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Towing with a CX-9 once I hear back from Mazda about their tongue weight capacity.
T he distance from hitch to axle is 11.5 ft and from axle to end of trailer is 4.5, total length from hitch to the end of the trailer is 16ft
ShrimpHappens, née WJalopy
> whatisthatsound
06/10/2019 at 14:29 |
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Just remember, if that sumbitch starts swaying on you, don’t hit the brakes. Coast down.
nermal
> whatisthatsound
06/10/2019 at 17:54 |
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I’d err on the side of caution, and go front in. Take it for a pull, and as long as it handles ok don’t worry about it. Too much is better than not enough, especially the faster you go.
Make sure the trailer sits level when hooked up to your truck as well. Having the hitch too high or too low will cause it to handle funny.
Dusty Ventures
> ShrimpHappens, née WJalopy
06/10/2019 at 20:04 |
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Alternately, if he has a trailer brake controller he can use that.
My bird IS the word
> whatisthatsound
06/10/2019 at 20:59 |
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Know nothing about towing, but wouldnt the morgan be front heavy, better to put weight closer to the front of the trailer? Less leverage?
John Norris (AngryDrifter)
> whatisthatsound
06/10/2019 at 21:18 |
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functionoverfashion
> whatisthatsound
06/10/2019 at 21:29 |
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I’ve towed a lot of small-ish boats in the weight range your’re in. I’d be more comfortable with the 350lb tongue weight setup you described than the 500. 500lbs is a lot for a ~2,500lb trailer. Either way is going to be unlikely to cause a problem. I’m guessing you have only surge brakes on the trailer?
RacinBob
> whatisthatsound
06/10/2019 at 21:32 |
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The question is “how does it tow” front in vs back in?.......
The advantage of too much tongue weight is it will will follow a sudden lane change without trying to steer the back end. But nose in means 800 pounds tongue more weight and as a result your headlights pointed to the sky unless air shocks.
I would try tail in as long as the tail isn’t wagging the dog....
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whatisthatsound
> functionoverfashion
06/10/2019 at 21:36 |
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No, I upgraded to electric brakes with a controller to make it all smooth.
Cash Rewards
> John Norris (AngryDrifter)
06/10/2019 at 22:00 |
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Thats a great demo
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functionoverfashion
> whatisthatsound
06/10/2019 at 22:00 |
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Then with a CX-9 as the tow vehicle, I’m going with 350lbs. Not for any scientific reason (beyond what you’ve done, that is) , just gut feeling. That’s my two cents.
I’m assuming you feel comfortable with tie-downs being very secure in either configuration.
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functionoverfashion
> Dusty Ventures
06/10/2019 at 22:06 |
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Somewhat surprisingly, for such a small trailer, he says he does have that setup.
EngineerWithTools
> whatisthatsound
06/10/2019 at 22:06 |
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Practically speaking, I can’t add to what has been said: Make sure it’s level( ish), a little more on the tongue is better than a little less. If it sways, do not slam on the brakes, although if you have electric trailer brakes, you can ease into them alone to straighten it out.
Mathematically speaking, there is a funny coincidence in the geometry of your trailer and Morgan. If you load the tongue to 10% of the total, then the Morgan CG and the trailer CG are in the same spot. This also happens to put the Morgan rear axle directly over the trailer axle, if the Morgan is pulled in.
On review, the CGs lining up make some sense, as the trailer manufacturer was shooting for ~10% on the tongue empty. The trailer and the Morgan are close to the same weight, so it follows that the Morgan CG will be in the same spot as the trailer’s for 10% on the tongue.
Anyway, details:
10% on the tongue = Morgan CG 124" fro m tongue = Morgan front axle 30" from tongue = Morgan rear axle over the trailer axle.
15% on the tongue = Morgan CG 111" from tongue = Morgan front axle 17" from tongue = Morgan rear axle 27" in front of trailer rear axle.
It’s tough to figure weight ahead / weight behind because we don’t know the trailer weight distribution, which is different (but related to) the CG. If you put the Morgan rear over the trailer axle or a little in front, I don’t see how you can have too much weight behind the axle.
Oh, and your Morgan’s CG (empty) is 37" from the front axle.
Work attached....
ITA97, now with more Jag @ opposite-lock.com
> whatisthatsound
06/10/2019 at 22:57 |
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I was afraid the math was going to be worse with it in backwards, and I think you’re close enough to try either way and see how the truck does. More weight on the tongue will basically never hurt from the standpoint of trailer stability, but you can certainly put more weight on the back of the truck than it can handle and that will cause stability problems of a slightly different kind in that the truck will be susceptible to having the tail wag the dog, so to speak, as the light front end will struggle to maintain tracking.
Good job springing for trailer brakes on that size trailer , as you’re going to want them towing with a car- based CUV. Normally, I would all but automatically load this set up heavy end forward, but f or towing with the CX-9 I’d be inclined to try it backed in first and see how it works. 500lbs+ will be a lot of tongue weight hanging behind the rear for anything less than than a 1/2 ton truck or 1/2 ton truck based SUV. If you’ve got some other cargo for the trips that you could load in the front of the trailer with it backed in, that would certainly help out a bit.
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whatisthatsound
> EngineerWithTools
06/11/2019 at 00:32 |
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If you ever want to borrow it for a day come on up, I appreciate the help.
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whatisthatsound
> ITA97, now with more Jag @ opposite-lock.com
06/11/2019 at 19:12 |
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Thank you!
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whatisthatsound
> EngineerWithTools
06/11/2019 at 19:12 |
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Also, do you think I’m okay backing in to keep the tongue weight at around 350, that way I can use my weight distribution hitch?
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EngineerWithTools
> whatisthatsound
06/11/2019 at 21:13 |
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Yes! 350 lbs on the tongue puts the Morgan CG 113" from the tongue, which in turn puts the backed -in Morgan’s front axle 12" behind the trailer axle.
(Note that the below says “behind rear axle”, it should say “behind trailer axle ”. You’re not required to turn the Morgan inside out.)
