Material for Strengthening of Pedals

[Mono]

I wonder which material could be used to strengthen the above pedal at the predetermined breaking point where it broke, in particular before it breaks  I guess the material should be strong and bind well with the pedal material, which I assume is some aluminium alloy. Would epoxy work? Is there anything in car DIY shops which fits the bill? In fact, I really have no experience with this kind of patching work what-so-ever, so I am curious whether anybody else has some hints...

 

[Heyzeus]

Using vibranium should meet most use cases

Someone in that thread was saying that the material may not be the issue so much as the way it's forged.

That if it were to be cnc machined that would probably solve many of the issues though the inmotion pedal looks like it's issue may be more design than the material its made of

[Hunka Hunka Burning Love]

I'm no structural design engineer, but looking at the failure of the InMotion pedal in that thread, it looks like the area near the mounting pin receives the most stress in supporting the rider.  The honeycomb design looks strong, but they could have filled in the honeycomb structure with solid fill near the edge where the hinge area is.  A solid block of metal there might be able to resist forces better?  I imagine the pedal as basically a lever.  Where do levers break?  Near the pivot point usually.  We've never seen a pedal break in half but rather at the edge as the forces concentrate near the pivot.

Imagine if you are 3D printing a pedal.  Would you leave the area near the edge where the hinge is unfilled, or would it be stronger with a solid fill?

I wonder if a different cast alloy like what they make bicycle crank arms out of (or tool quality chrome vanadium steel alloy) would end these breakages once and for all.  All the rider weight is on the pedals so they are a critical part of the wheel design.

[Electroman]

Machining and casting is night and day, if you look at Alu there is actually a separation with the classifications for wrought and cast.

 

Take wrought for example and start by first number will stand for alloying elements, for ex 6 that so many wrongfully refer to as "aerospace grade Alu" it tell us that we will find Magnesium and Silicon in it and quite a bit more tensile strength. Alu is alloyed differently depending on whet it's intended for and please do go check this up it's quite interesting how properties change so much by slight changes is compositions, wrought systems have 4 numbers but can also one additional info like temper designation.

Too much to even behind to scratch the surface here and still so much to learn, the field of metals is huge, but as a ruler you could say these products we stand upon is mostly case from very "dirty" China alloys, very cheap and attainable for them in quantity for next to nothing. To me it's shameful cause with out safety on the line just a single $ extra per pedal when choosing material would go a long, long way.

Forget trying to mend this, if people fully understood what they are standing on I believe the would think twice but that's just me, on the other hand I do have some insight and I still cannot help myself when riding so?

[Mono]

I see that I express myself poorly. I would be interested to add material to an original pedal to strengthen the pedal I have, instead build a new one.

[mrelwood]

I didn’t look at the structure awfully closely, but I did already think that pretty much anything at the top of the pedal would so wonders. Aluminium and thin steel plates are easily available. If attached properly, such top plate on the pedal would directly help in sharing the largest forces at the weakest point.

Unfortunately the rubber piece would then be gone, and the plate would be covered by grip tape.

[Mono]

8 hours ago, mrelwood said:

If attached properly

That seems crucial to me though. I am not sure to see how one can attach a metal plate in a way such that it improves the structural integrity. Obviously, for this one would have to find fixation points on both sides of the breakage. One side is easy, but the other?

[Planemo]

It wouldn't be easy to retro-fit something to deal with the issue at hand, for example 'overlaying' something that picks up from the factory pivot points and rests on the stock plate. You would be far better off creating a new plate from scratch. In fact, the idea kept me up last night, now that I have visions of my V5F pedal falling off. The easiest way to do it IMO is create a 3D CAD, send it to a machinist and 3D CNC it in billet aluminium.

This wouldn't be cheap, but then neither is reconstructive facial surgery, not to mention potential lifelong injuries.

It would be much cheaper per unit to cast *proper* plates that have been designed correctly (read: stress analysed) if they were mass produced but this isn't really an option for the budding entrepreneur due to initial cost. The major players could fund it but they are probably paranoid about adding £50 to the cost of an EUC.

I am surprised that no-one has gone the billet route, it could also provide multiple foot plate sizes to suit the user with minimal CAD alteration. Given than most plates can be adapted to fit most EUCs with the simple addition of correctly sized spacers (easy to source/machine), it's not like you would need to create a multitude of designs or billets for the plates. Maybe a range of say 4 plates to cover foot sizes 5 to 7, 7 to 9, 9 to 11 and 11 to 13. I appreciate that the section of plate which rests against the drop hanger might vary between manufacturers, but even this could be dealt with by using PTFE spacers which hang off the main spindle and rotate with the pedal. Anything to keep the number of different plates down would be the goal.

[Mono]

43 minutes ago, Planemo said:

In fact, the idea kept me up last night, now that I have visions of my V5F pedal falling off.

I can't remember to have seen a single incident of V5/V5F/V8 pedals failing, and those are much more often sold than the V10 pedals that broke. My V8 pedals started to point downwards after 2 years of use, but that seems to be how far it gets. Losing sleep over these pedals breaking is probably not worth it.

[Planemo]

Yeah I'm sure you're right my friend, I am overthinking the concern but still it worries me. It seems that all the sods laws in the world seem to gather together to take people off their EUC's and I just want to minimize that as much as possible! I still think that someone machining plates would be a good idea, if only for the sizing issue. They could also be made to be a better shape for our feet (like the prototype Z10, which I thought looked pretty good) unlike the big symmetrical blobs which are currently favoured.

[Mono]

Could this cold welding work to reinforce the pedal material where the crack is most likely to happen?

[Dancer]

2 hours ago, Planemo said:

It wouldn't be easy to retro-fit something to deal with the issue at hand, for example 'overlaying' something that picks up from the factory pivot points and rests on the stock plate. You would be far better off creating a new plate from scratch. In fact, the idea kept me up last night, now that I have visions of my V5F pedal falling off. The easiest way to do it IMO is create a 3D CAD, send it to a machinist and 3D CNC it in billet aluminium.

This wouldn't be cheap, but then neither is reconstructive facial surgery, not to mention potential lifelong injuries.

It would be much cheaper per unit to cast *proper* plates that have been designed correctly (read: stress analysed) if they were mass produced but this isn't really an option for the budding entrepreneur due to initial cost. The major players could fund it but they are probably paranoid about adding £50 to the cost of an EUC.

I am surprised that no-one has gone the billet route, it could also provide multiple foot plate sizes to suit the user with minimal CAD alteration. Given than most plates can be adapted to fit most EUCs with the simple addition of correctly sized spacers (easy to source/machine), it's not like you would need to create a multitude of designs or billets for the plates. Maybe a range of say 4 plates to cover foot sizes 5 to 7, 7 to 9, 9 to 11 and 11 to 13. I appreciate that the section of plate which rests against the drop hanger might vary between manufacturers, but even this could be dealt with by using PTFE spacers which hang off the main spindle and rotate with the pedal. Anything to keep the number of different plates down would be the goal.

I made padels out of aluminium EN AW6060 T66 and have been riding them tot over 20,000 km without any problems.

 

[Planemo]

Mono - no I don't think that JB weld will help - there just isn't enough material to bind it against, especially at such high stress.

Dancer - excellent! That's exactly what I was thinking. I see that they were very expensive to produce - that was my concern. Did you try any other machine shops for price or just the one? I saw you made a different design and made them yourself - very good!

[RockyTop]

  I have worked with a good number of epoxies from resins to cold weld metal. They can do some amazing things with it but I don’t see it working here. In the end you are trying to gap glue one side of the hexagon to the other. You are trying to keep it from pulling apart. The epoxy could kinda do this for a while. 

  The MSX pedals are not the same as the older ACM and Monster pedals. Even the newer Monster pedals have been improved. They added more meat to the hinge side of the pedals. My complaint with the GW pedals is not with the pedals themselves. My complaint is that the force should be transferred far from the hinge like the KS pedals. They have that extra part that folds under the pedal post. 

  

[Electroman]

1 hour ago, Dancer said:

I made padels out of aluminium EN AW6060 T66 and have been riding them tot over 20,000 km without any problems.

 

Very interesting, warm my heart to see a project such as this one.

Software is certainly not my strong suite, but can you virtually stress test in a program such as that one?

In regards to "strengthen up" a already existing pedal, yes interesting too, I am absolutely no pedal expert whatsoever but I do know from work that when strengthen existing load carrying structures at times there can be even more calculations than just doing it from scratch cause when changing stress points a lot of unexpected things can start to happen you did not intend that can change the whole dynamic in a way that can be hard to understand and does not always even make sense at first look.

But again these are EUC pedals we talk about and not some overseen project with lots of lives on the line if done the wrong way, if there is quick fix I could not say, personally I think some clever design would be needed to start eliminating inherent weak points but maybe it is possible to add strength by for ex "sandwiching" the existing pedal or playing with other materials, perhaps dress up most of the  pedal in a layer of carbon fiber but just throwing it out there so?

With access to machining and Alu alloy blocks of usable composition woudl be by far the superior way of doing it, that 6060 project looks amazing, Gotway take notes! Perhaps consider regaining some of the expenses and time invested (time is money too so) by making more an selling a few?

 

[Mono]

4 hours ago, Planemo said:

Mono - no I don't think that JB weld will help - there just isn't enough material to bind it against, especially at such high stress.

I don't understand, to me it looks like the pedal inside is all surface, which would be lots of material to bind to to make it thicker.