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Hitch mounted carrier - weight limits


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Have a good lead on a local hitch mounted rack for my Rally.

Rack is rated for 400lbs

 

Rally is 340-350lbs

 

How comfortable would you guys being that close to the rated limit? Never used a rack like this before and have no idea if the ratings are optimistic or legit.

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Should be fine, I make sure to secure my bike to the truck and not just the rack, otherwise bike and rack are going to be bouncing all over the place on every little bump you hit. All that weight bouncing around is what will get you into trouble, if it's secure it's fine.

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Whats your hitch rated for...  Bike hanging out there puts leverage and more effective weight than true weight of the bike. 

I put an updated hitch on my vehicle that can carry more than I can tow.  Fully frame welded.  Rail is fully welded over built rail.  Theaded hitch pin locks the receiver... No sway... No bounce... No unnecessary leverage from motion.  

My wheels will fall off the van before the bike will.  👍

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Would not hesitate to load to the limit on a commercially manufactured hitch (not a homemade job). Should come with some sort of stabilizing clamps. If not, not too expensive to add. I tie the loose end of my front straps to the forks and the truck, plus both straps go from forks (Canyon Dancer tie down rings) to my chain hooks on the truck receiver, which is rated at 600 pounds for none weight-distributing hitch. Canyon Dancer's attach to the fork clamp bolts.

5b04cbd0b1ade_CanyonDancer.jpg.bf6934fb6a66cc5b07d24a092abcc765.jpg

Love my little hitch carrier. Ultra-Tow aluminum. Around 50 pounds and $170 at Northern Tool. 400 pound limit, which is fine for any dirt bike I care to ride. 👍

 YZ250-Hitch-in-the-Hood.jpg.33c469c0ca84cb1bc02e89d702067d9b.jpg

Edited by LSHD
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I echo the suggestion to secure the bike to the vehicle to help stabilize. Not sure if you can tell in the picture below, but there is a pipe that runs from the roof rack to the bike and is secured at each end. If any of the straps fail, it will keep the bike vertical. It’s also handy when unloading as I can undo all the straps and detach the bar last just before wheeling the bike off.

I took a mental inventory if at anytime in my past I’ve had straps fail and the answer was “yes” and thus I wanted a backup in case (when) that happens so my YZ didn’t do a dozen cartwheels down the freeway or get dragged on its side for a mile.

Note: the bar does not provide any weight bearing support whatsoever, so it will not increase carrying capacity.

P.S. the Element pictured sagged 1” with the bike on the trailer so I put those rubber things in the coils to stiffen the rear. Reduced the sag to half an inch.


IMG_8618.JPG

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They are convenient as hell, have a 400# rated hitch-haul, does fine on my truck, but only have a 350# tounge rating on my 08 Santa fe, the hitch flexes, rear sags, and scrapes on occasion over uneven ground being the weight is so far from the hitch frame.  I will use it for my little offroad stuff, but got a 2 bike folding trailer for my 250L, and the wife's CB300F, a lot more expensive than a hitch hauler, more cumbersome to store and manuver around, but can do more, and easier to transport.   

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“Cantilever“ transfers to tongue weight. It’s just the mechanism for creating the force. At the end of the day it’s a downward force on the tongue

 

Though of course a 200 pound weight 18 inches past the tongue is going to translate to more than 200 pounds at the tounge.

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I've used the MX Hauler with both my KTM (pictured) and my WR250R (whale of a bike ..well over 300 lbs) without an issue. 

Rating for this hitch carrier is 375 lbs. I bet my WR250R with all it's wolfman racks and bags along with the rotopax fuel cans it's pushing 340 lbs. 

 

 

 

 

IMG_0723.jpg

IMG_0724.jpg

Edited by shrub73
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4 minutes ago, Torchsport said:

Nice T4 TRD PRO! I'm pondering an order for a new one in Cavalry Blue.

Cool color for sure!. 

Can you still buy them new or are the 2019's being ordered now instead. Cavalry will not carry over to 19. 

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2 hours ago, Tahoe Gator said:

“Cantilever“ transfers to tongue weight. It’s just the mechanism for creating the force. At the end of the day it’s a downward force on the tongue. Though of course a 200 pound weight 18 inches past the tongue is going to translate to more than 200 pounds at the tounge.

Not exactly. The downward weight is exactly the same no matter the length of the cantilever beam. The rotational torque on the hitch increases with cantilever load. It appears to me that most receivers are overbuilt for cantilever load expected when a trailer flexes at the design tongue weight.

It would seem clear that a hitch carrier puts loads on a hitch that are similar to an extended hitch, but eTrailer and other vendors say that rated tongue weight does not change for using a hitch carrier, while it is reduced by 50% while using a hitch extension. I don't know why.

Here is a fantastic online calculator for analyzing load on an extended hitch. Just use zero for the loaded trailer weight and the weight of the loaded hitch hauler as the tongue weight. It won't be a perfect but is a good tool for visualizing the loads on the vehicle and hitch receiver.

http://www.visualsc.com/hitch_calc.htm

Edited by LSHD
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Not exactly. The downward weight is exactly the same no matter the length of the cantilever beam. The rotational torque on the hitch increases with cantilever load. It appears to me that most receivers are overbuilt for cantilever load expected when a trailer flexes at the design tongue weight.
It would seem clear that a hitch carrier puts loads on a hitch that are similar to an extended hitch, but eTrailer and other vendors say that rated tongue weight does not change for using a hitch carrier, while it is reduced by 50% while using a hitch extension. I don't know why.
Here is a fantastic online calculator for analyzing load on an extended hitch. Just use zero for the loaded trailer weight and the weight of the loaded hitch hauler as the tongue weight. It won't be a perfect but is a good tool for visualizing the loads on the vehicle and hitch receiver.
http://www.visualsc.com/hitch_calc.htm


The hitch doesn’t know how long the beam behind it is. One foot or 100 feet. All it knows (“feels”) is a force.

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2 minutes ago, Tahoe Gator said:

The hitch doesn’t know how long the beam behind it is. One foot or 100 feet. All it knows (“feels”) is a force.

 

Nope. The hitch feels two forces, torque (moment arm) and downward force. It doesn't "know" how long the beam is, but the length of that beam and the weight of the load changes the torque proportionally. Twice the beam length for the same load equals twice the torque, while downward force is constant regardless of beam length. LSHD = MSME Georgia Tech, Class of '96. 👍  I am wrong about a lot of things, but this is not one of them.

In the two free body diagrams you can see that tongue weight (Ry) stays the same (bike weight plus hitch carrier weight), but the torque on the hitch (pulling or pushing on the bolt-on locations, depending on which bolts you look at) changes with load beam length.

5b06174ab939c_BeamBendingHitchCarrier.png.4e519c3bc2be926b574db52f2d0a467c.png

5b06174a009e7_BeamBendingHitchCarrier2.png.5eb7fa4dad9a85bc3fddd16dcb9de494.png

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34 minutes ago, Tahoe Gator said:

The hitch doesn’t know how long the beam behind it is. One foot or 100 feet. All it knows (“feels”) is a force.

 

I do think the downward force is what we need to know, but it's not the tongue weight. It's the tongue weight plus the torque created by the beam lever, applied at the rear attachment of the hitch receiver. In this case you would assume the bolts toward the front of the vehicle are pins, then add the tongue weight plus torque created between the front and rear bolts. Add that up and get the total force trying to pull the rear hitch bolts out of the frame of the vehicle. Those bolts are pretty strong, so I'm thinking that is why hitch carrier manufacturers use the lesser of tongue weight and hitch capacity as their load limit.

In the below examples the up arrows show how much force the rear bolts have to support with the bike centered at 20" and 30". You can see how that force goes up as the load moves further behind the hitch receiver supports. And maybe that is what you meant by the hitch receiver only has to worry about one force. Bending the hitch receiver is not much of a concern, as these are really overbuilt. It's the attachment points to the vehicle that determine tongue weight.

5b061ac1c2759_BeamMoment20.png.95db1aafcbdcc6538dd5fe292ce7b441.png

5b061ac119f75_BeamMoment30.png.8e0892bf6284b7b8194e09d02b53e727.png

Edited by LSHD
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Torque at the “pivot” I get. Of course your schematics are accurate in terms of torque in that regard. No debate there whatsoever. But it’s not really a pivot point, or rather not a point of failure. The sleeve of steel the carrier sits in could probably handle thousands of pounds. The stress as you say is on the anchor points (which are not at the tongue location) and which is translated from the force at the tongue by the carrier. My point is that a hitch designed for 400 lbs of tongue weight cannot support 400 lbs way out on a beam. But in a sense the anchor points don’t know where the force is applied per se. They feel a certain force with let’s say a 400 lb weight on the tongue (let’s say if a trailer hitch ball) and they feel a force from a hitch mounted carrier that could be the same or more depending on weight and beam length. Eg: There is some weight of a carrier at some distance from the hitch that, to the anchor points, is the same as if a certain weight were applied at a trailer hitch ball. That’s all I was trying to say.

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