Ready Brute Elite II Question

[pilotspike]

Two thoughts, errr, a thought question and an experiment idea....


Thought question: Is this a significantly different situation from that of a load equalizing hitch? It would seem to me in that system the spring bars would have to give in order for there to be independent rotation between tow vehicle and trailer. I wouldn't think that there would be a lot of give given the weights and forces on those bars. That would then imply that in those systems those bars are forcing the vehicle chassis to work as well.


A little back of the envelope trig makes me think that a 4" pothole, on a jeep wrangler (64" track) imparts about 3.5degrees of twist at the roll center, assuming zero suspension movement and that the roll center is equidistant between tires. That doesn't sound like a whole lot to be absorbed by the combined suspension of the two vehicles and any slop in the system. Now granted, In order for the suspensions to absorb that force, it has to be transmitted through the tow bar but it would seem to make sense that they could make the bar strong enough to do that.




Anyone ever watch a 300lb person sit in a drivers seat and watch the left side of the car drop? Granted that scenario isn't considering the leverage associated with transfer through a 2" receiver, but maybe this isn't as bad as we are thinking?


But then, my math/analysis could be really off too




Experiment idea: Someone (in the warmer climates ) with the previous version of the Ready Brute Elite hook up their two vehicle and jack one side of it 4" up from its position of rest and see what the deflection is on the twisty joint. It might be interesting to see how much movement is actually happening.


J

[Vato]

Originally Posted by Percival6

Thanks for your comments. I had my son ride in the toad when I tested the set up the first time at about 30 mph.. According to him, after repeated stops the brakes would engage and the pedal would be pulled between 1"-2.5' depending on how quickly I stopped the rig. I adjusted the cable again to the point that I could just barely attach it when the arms are extended. I believe it is applying sufficient braking force to be effective.

Tom,
If you don't already have one I highly suggest the dash light that activates when your toad brake pedal is compressed (your son won't have to ride in the coach....lol)

Mechanical bracket with a brake light switch

Takes the guessing out of when your toad brakes are activated, provides a great peace of mind that your brakes aren't being activated due to some unforeseen issue (like cable stuck on something)

Then you can adjust your cable to your desired activation

I use 2 dash lights, 1 for the RB lever and 1 for the toad brake pedal. I can monitor when the RB lever is activated and when the toad brake pedal activated.

If nothing else it's entertaining....lol

Fireup developed a great cable adjustment method... Put a turnbuckle in the cable line for fine tuning

https://www.etrailer.com/Tow-Bar-Bra...oaAuAyEALw_wcB

[Percival6]

Sorry for my delay in getting back to everyone. I had to catch up on a lot of other things before I could even think about getting back to the topic.


yeloduster,
Thanks for the info on the repair kit. I think you're right, that is probably not the cause for the redesign.



As for your thoughts on the arms being able to twist, individually the arms do rotate, but when both arms attached to the toad there is next to no rotational movement. That is why I posted to begin with. The only points on the set-up that will allow any movement are where the arms connect to each other and pivot from side to side (that is very minimal) and where the tow bar connects to the hitch receiver.

As another post suggested, the suspension would take up some of the stress, but I'm still thinking that is a lot of unnecessary stress being transmitted through the tow bar to the vehicle parts, especially on a car with a unit-body construction.

Originally Posted by yeloduster

Having just installed the repair kit for the Universal Joint I would say that warranty costs are not the driving factor. The kit consisted of a bolt and washer. Maybe $5 worth. I'm sure it cost them more to ship it than the parts. The driving factor behind the change is manufacturing costs. The new tow bar has fewer parts and takes less labor to assemble.

Part of me wonders if we are overthinking this issue of rotation on the longitudinal axis. I've looked at pictures of most other tow bars and it seems that some tow bars allow this rotation and some don't.

It seems to me that any additional stresses caused would be most felt at the junction of the tow bar arms. The arms have considerable twist leverage at that point and on the receiver hitch. I think the springs in the front suspension of the toad might allow the toad a few degrees of rotation and that is all it takes.

I worked as an engineer in a manufacturing facility and learned that most often the simplest design was the most reliable and the safest. Perhaps that is true here.

[Percival6]

Alan,
Let us know if you hear anything back from them. Thanks!

Originally Posted by Alan_Hepburn

just for fun I just sent off an email to NSA asking them if their design teams have addressed this concern - I'll post any response I get back from them...

[Percival6]

Having owned a trailer and equalizing hitch before, the springs bars do have a large amount of movement especially when turning and going off camber, but either the chains or the friction pads allow that movement. The main stresses on those vehicles would be mainly fore and aft, directly down the centerline of the tow vehicle and trailer. There would be relatively little torsional stress in this setup. This setup would be similar to the previous models of the Ready Brute Elite that had the universal joint and allowed for the rotational movement.


Your thinking about the pothole (and other road hazards, for that matter) would be correct. The suspension would or should absorb most of the stresses before they were transmitted through the tow bar. My main concerns are curbs, gutters, driveways, etc. that would be much greater than the 3.5 degrees. Yes, the suspension would have more time to flex, but I'm worried there would be a lot more stress through the tow bar. I agree the tow bar is more than likely strong enough, but the frames of the RV and toad (especially unit-body frame) vehicles might not be.


I second the experiment idea!

Originally Posted by pilotspike

Two thoughts, errr, a thought question and an experiment idea....


Thought question: Is this a significantly different situation from that of a load equalizing hitch? It would seem to me in that system the spring bars would have to give in order for there to be independent rotation between tow vehicle and trailer. I wouldn't think that there would be a lot of give given the weights and forces on those bars. That would then imply that in those systems those bars are forcing the vehicle chassis to work as well.


A little back of the envelope trig makes me think that a 4" pothole, on a jeep wrangler (64" track) imparts about 3.5degrees of twist at the roll center, assuming zero suspension movement and that the roll center is equidistant between tires. That doesn't sound like a whole lot to be absorbed by the combined suspension of the two vehicles and any slop in the system. Now granted, In order for the suspensions to absorb that force, it has to be transmitted through the tow bar but it would seem to make sense that they could make the bar strong enough to do that.




Anyone ever watch a 300lb person sit in a drivers seat and watch the left side of the car drop? Granted that scenario isn't considering the leverage associated with transfer through a 2" receiver, but maybe this isn't as bad as we are thinking?


But then, my math/analysis could be really off too




Experiment idea: Someone (in the warmer climates ) with the previous version of the Ready Brute Elite hook up their two vehicle and jack one side of it 4" up from its position of rest and see what the deflection is on the twisty joint. It might be interesting to see how much movement is actually happening.


J

[Percival6]

Vato,


I did attach the light, but have it resting on the dashboard of the toad. In most instances, except direct, bright sunlight its visible.


I am quite certain my son would not appreciate having to sit in the toad on a 300 mile long trip! LMAO!!!

Seriously, I only had him in there for about a mile in total, at up to 40 MPH then braking to have him report on how far the brake pedal was pulled. I did this repeatedly at different braking forces to make sure it would work correctly.


You know what? Now that you mention the turnbuckle, NSA did include one with the kit. I don't think I need it now that I have the cable adjusted and its stretched from use.

Originally Posted by Vato

Tom,
If you don't already have one I highly suggest the dash light that activates when your toad brake pedal is compressed (your son won't have to ride in the coach....lol)

Mechanical bracket with a brake light switch

Takes the guessing out of when your toad brakes are activated, provides a great peace of mind that your brakes aren't being activated due to some unforeseen issue (like cable stuck on something)

Then you can adjust your cable to your desired activation

I use 2 dash lights, 1 for the RB lever and 1 for the toad brake pedal. I can monitor when the RB lever is activated and when the toad brake pedal activated.

If nothing else it's entertaining....lol

Fireup developed a great cable adjustment method... Put a turnbuckle in the cable line for fine tuning

https://www.etrailer.com/Tow-Bar-Bra...oaAuAyEALw_wcB

[Alan_Hepburn]

Originally Posted by Percival6

Alan,
Let us know if you hear anything back from them. Thanks!

No response yet...