Tired of Cranks — Repurpose Them — to the likes of The MC Pivot Pegz

[DingusMcGee]

If you are going to put pegs on your edirtbike, there is a way to employ the ends of the cranks and pedals to make an MC peg similar in motion to the MC Pivot Pegz.

Here is a peek at the finished product made for an Isis crank



I could not find a flat head metric M12 x 1.0 bolt so I brazed, using high strength nickel-silver rod, (120 ksi yield), a class 12.9 flat head’s head on to the 8mm Allen wrench hole of the OEM Isis shaft/pedal retaining bolt. This bolt, when countersunk, makes for a flat surface through out the steel channel base and the pedal swivel then does not bump any bolt heads — except the stop which is on the bottom side.




A glimpse of the countersunk flathead


The Stop Rotation Mechanism. The gear clamps allow the spindle to be turned when torques get high enough. I figured this permitted rotation of the spindle may lessen the destruction some impact loads (wrecks) can cause. Below, the pedal hinge orientation is the standard 45 degrees up and forward.

 

[DingusMcGee]

Question,

https://endless-sphere.com/sphere/members/bananu7.106180/

bananu7, or any others,

Re: seeking optimal bike pedal fold up angle for adjustable angle fold up mechanisms of foot pegs

For MC foot pegs that do not rotate (as in a standard MC peg) the fold up hinge angle is always upward and usually 45 degrees forward. Pedal Pegz typically mount onto frames that are fixed at 45 degrees up and forward.

If the peg platform can rotate, as with Pedal Pegz or what I have made, is some hinge angle other than the standard 45 degrees up and forward better suited to pass against objects in the trail? In my design I can choose the fold up angle.

My intuition on this hinge angle sees up and 45 degrees backward as the better pedal fold up rotation direction when the pedal platform can rotate. The goal being smoother bumping and less hangups with fixed objects on the side of the trail.

 

[bananu7]

Why do you think they fold forward? Virtually all that I've seen fold backwards, like so:



(blue brake lever is front of the bike)

I believe the 45 deg is a reasonable compromise that allows deflection both from frontal impacts (tree, pole, etc.) and bottom impacts (roots, rocks, edges of ruts and bike fallen over). In motion, the hits will almost always be around that angle, and peg damage, while not unheard of, isn't exactly common.

EDIT: Oh, and that applies to Pivot Pegz too. The added axis they "pivot" around folds on the same folding axis as the stationary pegs do, as they reuse the mounting points.

 

[DingusMcGee]

bananu7,

You ask , “Why do you think they fold forward?” They do on my KX100. I looked at the hinge direction also on new Kawasakis at the dealer and they too fold forward. It seems that if pedal can rotate, then up and backwards is much better. I have mine so they hinge upward and backward — at about 45 degrees.

On the kx100 the pivot to pivot distance is 10.25” and the edirtbike has 10”.

 

[A-DamW]

You ask , “Why do you think they fold forward?” They do on my KX100. I looked at the hinge direction also on new Kawasakis at the dealer and they too fold forward. It seems that if pedal can rotate, then up and backwards is much better. I have mine so they hinge upward and backward — at about 45 degrees.

Yeah, I cannot imagine a situation where the pegs folding/rotating forward would be of any use, unless you ride in reverse.

 

[DingusMcGee]

A-DamW

endless-sphere.com

“Yeah, I cannot imagine a situation where the pegs folding/rotating forward would be of any use, unless you ride in reverse.”

Until you understand the configuration space of how the peg’s edges move WHEN GOING UPWARDS, as opposed to pivots pads when passing thru constrictions, the EDGE angle changes may not have been accounted for properly for you to reason, “…forward would be of any use,”.

Let’s consider the angle of the impediments we attempt to ride thru on the dirtbike trail. For simplicity there are “V” shaped sides or chanel “U” shaped troughs with very steep sides we encounter. If we only rode thru U troughs, the best peg folding angle would be straight back. But most tails have V troughs and sometimes they have a V side and a U side. We often attempt to ride on the V side to get away from the vertical U wall side.

Now, here is the subtle point of how folding forward is sometimes better than folding back — when folding forward the peg’s leading edge on the downward side is upward when going outward along and to the end of the peg. So, with this configuration, the peg surfs up on the terrain while going forward. When the folding angle is to the back, the pegs leading bottom edge is in a configuration more likely to snag as it has a downward plow like configuration. I can see how Kawasaki designers went for the up and forward folding angle — it is better some of the time.

Once pivot pedal/pads are mounted, the Kawasaki advantage of pad encounter with objects can happen even when folding backward because the pedals can rotate into a similar rising folding angle pedal edge that Kawasaki employs. Complicated? Yes, I suggest you to a Kawasaki dealer to see and feel the peg movement of the way I say it happens.

Because of what is a big advantage when having more adjustment angle of the leading collision edge with pivot pads, a folding backwards setup would seem to pass thru V shaped troughs without introducing snag angles like the fixed pads would. So my latest pivot pad folding direction is up and backward.

Note the stop spindle rotation attachment between the crank end and the BB shell.

 

[DingusMcGee]

Bumper Pads?

Even though the pedal shaft rotates up and out of the path of an obstacle on the swivel quite easily, sometimes the pedal shaft would not go flat but remain vertical. The rider then has to locate enough of the pedal to push it flattish to support a foot or to stand upright on it.

A torsion spring, as used in flat common MC pegs, would be a difficult remake of these centered crank pedal ends (the swivel) to get the spring to fit on the swivel rotate shaft.

Since the swivels rotate quite easily, a solution might be a rubber bumper that made contact with the pedal bolt when the pedal was near vertical. The rubber bumper pad would also act as spring. The bumper pads were made of 3/8” ID black fuel hose and fastened with a cotter pin going thru the hose hole.

I did try 1/2” fuel hose with a longitudinal slit and hot glue for fastening but that method did not hold good enough.