MacGregorSailors.com

I've got the weighing scales set up under the towing hitch and I'm surprised at how heavy the nose weight is - it goes off the scale at 120kg. The max nose weight on my hitch and on my tow bar is 100kg.

I have tandem axles.

It's a daft question but does it make any difference if it is on a slight slope (towards the front) when measuring the nose weight?

My instinct says the geometry doesn't matter if it is on a slope but with tandem axles maybe it throws the weight forward a bit?

Any thoughts?

Mike

A slight slope will not make any difference

However the recommended nose weight should be 10% of the trailer weight or about 175 to 200 kg.
If there is not enough weight on the tongue the trailer will wag the tow vehicle pretty good.

With only a 100 kg hitch you may have too small a hitch or worse, too small a tow vehicle.

Just my 2 cents worth.

I have always wondered whether the noseweight was influenced by trailer balance? For example, how the trailer is loaded, where the wheels (especially tandem) are located on the trailer.

This is a question as I know nothing about trailers but this would seem be part of the equation.

Jim

Just curious. Has anyone ever checked the tongue weight of a Mac 26M right front the factory with just the outboard? I bought a tongue weight scale from Sherline and measured mine the other day and was surprised to find I had a reading of 600 lbs under the jockey wheel. I thought this was quite high based on the rule of thumb I have been seeing in this site. For info I have a 60 hp Etec and some added goodies like refrigeration(60 lbs) amidship, solar panel at stern, two spare tires at front of trailer. I had both 12 gal gas tanks full under seats; very little personal gear on board at the time; roller furling; and boom.

Based on this reading my plan is to carry more cruising gear when trailering at the stern. Comments with any experiences would be appreciated.

Curtiss

Hi Curtiss,
While my experience is not with a Mac26M, I have worked with the Sherline scale for about 6 years now. Have tested on My Odin 820 water ballasted powersailers, in different configs.

2004 Boat , Motor & Trailer Weight = Boat 3000 lbs , Motor 374 lbs, Trailer 1,300 lbs, Misc Equip-Fuel-Electronics & All = 1,200 lbs. So Aprox: 4,574 lbs without the trailer.
Trailer is tandem wheel 5 Starr USA Built, and the winch post is Adjustable in its horizontal mounting position on the trailer tongue.

I always measure Tongue weight using the Sherline positioned under the Ball, and not as far back as the jockey wheel. So adjustment for Me, is set @ 525 LBS on the scale.... Works fine for Me, as I am using an F250 Diesel to pull the entire rig around.

Will assume, you have a Mac with a Welded to Frame Winch Post..."That is not adjustable" ?
So Your Sherline weight is good for an F150 type truck, but appears to be heavy for a passenger car. Please let us know, what Vehicle You are using ?

Yeah, I've read on this site on a number of occassions about the 10% rule of thumb.

My tow vehicle is a Ford Maverick (UK) - same as a Nissan Terrano. Not a big beast but it is good for the job - max capacity for towed load of 2800kg according to the Ford manual. But at the same time the Ford manual says max nose weight of the towed load should be 120kg (not 100kg as I mistakenly said in my first post above). But 120kg is way less than 10% of 2800kg.

Similarly, the UK trailer is rated to carry up to 2700kg in tandem axle format but the tow hitch is again limited to only 120kg. Well, the boat and trailer aren't anywhere near 2700kg but they do weigh about 1800kg - 1900kg - so even on this basis, the max hitch is way less than 10% of the load.

It seems that both Ford and the UK trailer supplier are expecting a nose weight of about 6-7% of the max towed load .

Mike

Slope will indeed change the nose weight. The center of gravity is above the wheels, tilting toword the bow will shift weight forward. Just imagine a full tilt all the way. No weight on the wheels, all the weight on the bow. Also, moving the boat forward will shift weight forward. Actually, quite a bit. Try just 3" first and reweigh. Expect to get just about all the weight shift you need. Or move a litle more. Really should have near 10% on the trailer tounge. Our boats are sensitive to motor weight. Trailer is designed for 240 lbs of motor. Big motor will upset this plenty. Add 100 to the back and get about 50 lbs less bow weight!
Mike Inmon

Tandem axle trailers can be affected by hitch height, also. If the hitch is too low, the rear axle is unweighted, transferring weight to the rear. If the hitch is too high, the front axle is unweighted, transferring weight to the tongue. This can adversely affect tow vehicle handling and trailer tire wear.

~Rich

I am using a 2003 Ford Explorer 4X4 with 6 cylinder engine. In the literature I read it is rated for 5300 lbs for towing. I towed my Mac 26M to Anacortes WA from Sacaramento CA and back, about 1900 miles and had no major problems. I definitely had to pay attention as the steering was more "twitchy" than I was used to. I've since added a second axle to the trailer since I plan on towing it to Mexico in April and felt more secure about having extra wheels under the trailer. However adding the tandem axles has not changed the hitch weight all that much as I weighed it before and after. The center of the tandem axles are at the same location as the center of the original axle. I've just got my trailer back this week and in the limited towing from their work shop home the rig appears more stable in the steering department. Will be able to report back more later.

Curtiss

Mike UK:
It´s mainly because in US they have different standards for towing equipment etc...
In Europe there is usually the 120kg limit for nose of the trailer... The same on my Landrover Discovery 3 - max. 3500kg towing capacity and max. 120kg vertical load.

Here's another example:-

Mitsubishi L200 (is that sold worldwide?)
Engine in UK typically 2.5L - 3L turbo diesel
Max towed load 2700kg
Max tongue weight 115kg

Again, tongue weight will be less than 10% if the towed load is anything more than half of its max.

Anyway, I've finished adjusting my axle positions and will now move her to level ground to see what effect it has on the tongue weight.

Mike

I have a tandem axle OEM trailer and air bags on my Jeep GC---I can level my rig depending on how much I load the boat. Can hardly tell the boat is behind me at 65 mph.

Bob

curtiss wrote:Just curious. Has anyone ever checked the tongue weight of a Mac 26M right front the factory with just the outboard? I bought a tongue weight scale from Sherline and measured mine the other day and was surprised to find I had a reading of 600 lbs under the jockey wheel. I thought this was quite high based on the rule of thumb I have been seeing in this site. For info I have a 60 hp Etec and some added goodies like refrigeration(60 lbs) amidship, solar panel at stern, two spare tires at front of trailer. I had both 12 gal gas tanks full under seats; very little personal gear on board at the time; roller furling; and boom.

Curtis, My M has an etec 60 also and i received it with a decent amount of gas from the dealer. He brought it in an older jeep chair- oke and my spare was in there and not mounted on the @#%#@# I paid for. Your two spares on the trailer may need to go into the tow beast.
Remember where the axle's are when loading. All the heavy stuff needs to be with the beer in the rear birth. Maybe you will be able to keep the spares mounted. On a long haul like Mexico, I would keep all the heavy gear in the Explorer. 5300 lbs will add up very fast on a trip like that one.
Remember if it's too light on the tongue, the tow car will get the arse wiggles when you get up to 40 ish...? I have yet to get it too light to know what speed for sure. If the tongue is too heavy, you don't really feel it, but the front of the tow beast may get all screwed up.

Erik

That 600# seems pretty heavy Curtiss. It will trailer fine, but it will be heavily loading the tow vehicle's shocks/springs. If you are towing short distances/under 50 mph I would let it be - if you are on long high speed runs, it might be worth thinking about it.

You have to have a lot of tilt on a single axle trailer to make a difference on the tongue weight.

There can be a significant difference between the jockey wheel weight and the weight at the ball. The difference will be roughly the ratio of the differences between the wheel/ball and the distance to the centre of rotation - without doing all the physics the axle will be a good approximation for this point. This could easily make the difference 100# or so.

The big safety issue for you folks with 120 kG tongue weight ratings (about 1/2 of the actual) is to make sure that your car can take this extra weight 'structurally' and that you arent going to break off the back of your car.

I don't have access to my boat right now but the factoring of the actual ball weight versus the weight at the jack (on a single axle trailer) is a ratio of the distance from the pivot point (axle).
I would think its about a 10% variance (approx 15 ft to the jack and 16.5 ft to the tongue)

So 600# could be 540# at the tongue which is on the high side but not srously if the loaded boat is 5,000#. better to ere on the high side for better control while towing.