So how much force is needed to break a bulkhead....not much

[hibshman25]

We wanted to run a repair kit on one of our sleds so we can personally monitor a repair kit in use.

We were going to just cut an ear in half but then decided we'd try to simulate a force on the ear to try and break it.

When the ski or arm impacts something that can't be absorbed in the upward motion of the suspension the force drives the lower a arm backwards in a linear direction. ( Green Arrow) This linear force then creates an outward force( Red Arrow) on the lower front ear and cause it to tear away from the bulkhead.

To simulate an outward force on the lower ear we turned down a piece of bar stock to fit the the lower ear hole and then struck it one time with only a 4lb sled hammer. Video link below shows the result.

http://www.youtube.com/watch?v=-bTv5BaPNyk

 

[yamajammer76]

Well see now there is an advantage to the Nytro subframe... it doesn't break... just bends. lol

 

[AKrider]

I thought that was a pretty good wack with the hammer.

 

[pat the rat]

Say what

 

[DigitalFusion]

I thought that was a pretty good wack with the hammer.

X2

 

[hibshman25]

The force of a 4lb sled hammer with an 18" handle doesn't seem like much when you compare it the force of whacking the end of a fallen tree along the edge of a trail at 35 mph.

The video demonstrates that the ears are not designed to withstand much outward tensile force.

 

[Jeffz]

 

[number1kyster]

My ski caught a curb at about 7 MPH crossing a road. Stopped the sled dead and I flew over the bars and landed on the ground in front of my sled. Bent both A arms on one side but the bulkhead was not damaged. I was surprised to say the least!

 

[yamajammer76]

The force of a 4lb sled hammer with an 18" handle doesn't seem like much when you compare it the force of whacking the end of a fallen tree along the edge of a trail at 35 mph.

The video demonstrates that the ears are not designed to withstand much outward tensile force.

True, but I would think once everything is "bolted" up and the entire bulkhead is working as one unit it would be able to stand much more force.

 

[greenthumb]

True, but I would think once everything is "bolted" up and the entire bulkhead is working as one unit it would be able to stand much more force.

I would agree.
I am not familiar the apex front at all, but it would appear to me that the way the force is applied in the video is not the way it would happen in the real world. Not to mention any prior damage to the sled in the video that you cannot see.

Clearly there are problems with breakages, and i have no doubt their product works, but it seems misleading to me.

 

[7 skulls]

A few winters ago, I landed off a rise on a hill (approached at 50mph, braked down to 25mph and popped over the crest in the air) right onto an exposed rock with my left ski. Right on the carbide with diagonal and lateral forces. Bent the hell out of my A-arms. The sound was like a gun shot. Bulkhead no damage.
My brother has nailed rocks, bent A-arms, bent spindles, No damage to bulkhead.
Like anything, it can happen but it must take a very hard hit.

 

[snoway]

Damn.....I mighta needed that part!!!!

 

[YAMAMISSILE]

Guys, it does happen! i ride hard but smart, like a lot of you, im sure. I broke my bulkhead without even realizing it a few weeks ago! Must have hit something under the snow. I contacted Hibshman25 about his products. He was very helpful and sent me a kit. The construction is top notch. Easy to install. I can tell you, no matter what you think about the video, without a doubt, his product will work! The piece of mind is well worth it. Cheap insurance if you ask me.

 

[DigitalFusion]

I'd be inlcined to agree that the product is 'prolly great and does work.. there are enough TY'ers rocking it that would say that. I just dont feel like the demo in the vid was very scientific at all.

I think personally I would have been more impressed with someone whacking the spindle instead of sticking a pin in the bulk head and smashing it with a sledge hammer. Hell, at the least put a full length pin between both a-arm mounts, which would resemble at least somewhat more realistic real world scenarios.

I dunno, maybe I just hate seeing a yamaha tortured like that!