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PostPosted: Mon Mar 17, 2014 8:36 pm 
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Location: High Point, NC
Thanks for the additional information. These are indeed very strong and durable.

Only Hobie can advise if they are still available.


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PostPosted: Thu Mar 20, 2014 6:33 pm 
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Location: Rockport TX
Fusioneng, I really like your approach to adding the epoxy, etc. Unfortunately, I don't think it will help me. See pics. I always break the shaft at the top around the pedal shaft hole. First you will hear a "pop" followed by a gradually increasing amount of play between the shaft and the pedal and shortly you will see a crack start to develop and then break. I've had 8 new model shafts do this. I never once had the older style break.

I use my Adventurer a LOT. From May to November I average probably 15-20 mi a day. Much better exercise than jogging :)

My gripe is that the old versions NEVER broke. And to the Dutch gentleman that commented that water force alone against the system can't break these shafts I invite you to come down and join me. I can install a new set of shafts and break them the same day. No hull slip and no bottoming out the pedals against the stops. Usually where you stress them the most is when you are starting up from a standing stop and over stress them before you have the advantage of the momentum of the mass of the boat moving, or when moving and then accelerating sharply.

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PostPosted: Thu Mar 20, 2014 6:50 pm 
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Roadrunner wrote:
GB2 wrote:
The easiest solution is to buy the V1 shafts and pedals and replace the V2 shafts.

What GB2 probably is probably referring to are the solid billet aluminum cranks, PN 81100001 (left) and 81105001 (right). Yes, they are very strong -- pretty bullet proof as far as I know. These list for $31 US each and do not come with pedals. )


Thank you for the clarification and yes those are the pedal shafts I am referring to. I just purchased them last month and they are in the current parts catalogue so as far as I know they are still available. It's easy to switch the shafts out. In my group of hard core saltwater kayak anglers where 10-20 miles a day on the ocean is the norm, shaft breakage is close to 25%.


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PostPosted: Fri Mar 21, 2014 6:45 am 
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Location: sarasota,fl
coastbum :
This is the first I have seen or heard reported on this forum of breakage at the location you are showing.

What I would do in this situation is on the next shaft that you get, shove a wad of paper into the shaft so it rests just below the pedal, then squeeze in that white Locktite marine epoxy ( http://www.homedepot.com/p/Loctite-0-85 ... /100371825) filling the void, put the pedal back in, then put the cap on the end of the shaft. If you can shove a small drill bit into the epoxy along the sides of the pedal on each side, even better (those drill bits are really strong, and the epoxy bonds to the flutes very well, don't worry about galvanic corrosion, the drill buts are mostly chromium and cobalt, they don't rust easily, and if buried in epoxy they will be in there forever. If you spread a little grease on the pedal threads, shaft, and pedal face before insertion, you will be able to remove the pedal afterward if needed). With the locktite marine epoxy you have plenty of work time so there is no rush, just wipe away the excess before is sets up. Do not use 5 minute epoxy, it does not hold up in water (only marine epoxy).

If you want extra assurance (but not as pretty), after assembly you just wrap high test fishing line (the braided kind they use for sharks (not mono-filiment) around the post at the top (after the pedal is installed) about a dozen turns should do it, then cover with epoxy (like I said not pretty but it will be very strong). You can also probably use guitar string, or fine high test stainless wire if available as well, again if buried in marine epoxy corrosion will not be a problem. If it were me I would do all three fixes ( including the drill bit trick in the area I described earlier) on any new shafts you put on the boat. Spray paint it black when done or else people make fun of you ( LOL).
I'm sure it will be a while before Hobie can address this known material problem and new shafts hit the streets (they are on the problem), these simple fixes will keep you from getting hurt or stranded in the mean time, and only take 5-10 minutes to apply, and only cost a couple dollars to do.

Hope this helps
Bob


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PostPosted: Fri Mar 21, 2014 7:20 am 
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Location: Missoula, Montana
It seems to me that the breaking pedal arms on Mirage Drives is a clear case of inadequate design and materials. Hobie needs to develop or return to the design of a pedal arm which absolutely doesn't break under any foreseeable use.

My sister is a masters bike racer who has competed in seven different kinds of bike racing, and who has received national masters medals. She has never heard of the crank arm on a bicycle breaking, despite the massive abuse which they receive in sports such as mountain biking, downhill bike racing, and trials. I have talked with bike repairmen, and they have never heard of a crank arm on a bike breaking. If bicyclists became aware that the crank arms on a brand of bicycles were breaking, nobody would buy that brand of bikes. Hobie is going to develop the same problem if it doesn't improve the design of the pedal arms on its Mirage Drive. This isn't rocket science; all Hobie needs to do is look at the design of bike crank arms, which have worked reliably for generations. Weight is just as important to bicyclists as it is to kayakers, so the weight of bike style pedal arms would not be prohibitive. I would gladly put up with a little additional weight in exchange for the comfort of knowing that the pedal arms on my Mirage Drive are not going to break when I am miles from shore.


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PostPosted: Sun Mar 23, 2014 5:06 am 
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How about getting some Stainless Steel square tubing and fabricating new ones? Unless I am missing something, all you would need is a hack saw to cut the tubing to length and a drill to drill 2 holes. Rough estimates, I could get the tubing delivered to my house for about $50. The SS would be stronger and less fatigue failure prone to the Al tubing. Plus you won't get galvanic corrosion since the pins are also SS.

Mine haven't failed yet (not too many hours on the drive), but I don't want to deal with his issue if I am off shore by my self. Paddling an Outback rigged for fishing a few miles would really suck.

Unless someone tells me I am missing something, I may just try this for the heck of it.


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PostPosted: Fri Apr 04, 2014 10:53 pm 
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Location: Rockport TX
Fusioneng, thanks for all the detail on using the epoxy. I may try that this weekend on a pair shafts.

The reason these things are breaking at the top like mine do is very simple. The round pedal shaft and a small reduced diameter part on the end that fits into the the smaller hole on the opposite side wall of the upright shaft. Then the little plastic end cap has an allen screw that screws down into the round pedal shaft to help it maintain position. What happens is that tiny end button on the round pedal shaft breaks off in the side wall of the upright shaft - see my pics and you will notice the little button is laying beside the round shaft. I punched that button out of the square shaft arm after the break.

Once that button breaks off then the round pedal shaft is not secured by anything but one sidewall and the allen screw, so it starts to wiggle and ultimately fatigues the inside face of the square shaft and it cracks, then breaks.

Notice the two arms I have in the pics have EXACTLY the same break patterns. I have six more if you'd like me to go dig them out :)

And Matt Miller - please take notice of these breaks because when one breaks at the top like mine it causes injury. The pedal snaps off on a downstroke and that jagged edge of the shaft goes straight into the inside of your calf.

I just bought two sets of the old solid shafts from Hobie and one question I'd like to ask is does anyone know of a good set of screw in bike type pedals that you can comfortably use barefoot. I really like just the normal Hobie pedals but I obviously can't use them. I'd like to find a set of screw in pedals with the same type pedaling platform as Hobies.

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PostPosted: Sat Apr 05, 2014 12:15 am 
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Location: Escondido
Google "barefoot bicycle pedals" and you should find a nice selection of smooth pedals. Sunlite has a set that sells at Walmart for about $13 -- here is a link:
http://www.walmart.com/ip/Sunlite-Pedal ... 90&veh=sem

If you want the cushion pad (like what's on your Hobie pedals), you can buy them from Hobie and stick them on -- check out the parts catalog for the price and part #. 8)


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PostPosted: Sat Apr 05, 2014 5:38 am 
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Location: sarasota,fl
Coastbum:
This is new evidence to me, my pedals are 2012 pedals and I have never had a problem and don't expect to. It appears only recent pedals have problems (actually in two areas).
One thing that I do is always look for root causes of manufacturing problems, that's what I do for a living.
Just glancing at your pic is telling me the aluminum shaft itself may not be the root cause of your failures. It's what they call a resultant failure.
The tell on this is the grey break on the reduced dia end of the round pedal shaft. It should not break like that. That's a stress fracture, in steel if you have sharp corners stress is concentrated a those points, simple addition of a .030 radius on that inside corner during the screw machine operation would likely eliminate the problem. Also if the shaft is heat treated 400 series stainless, this material has a dead mans heat treat zone (Rc 52-54), if not tempered properly it become very brittle and pretty useless. Actually if the shaft is heat treated, and the corner must be sharp you will typically see the diameter reduced with a radius right at the inside corner (like a groove). At leas that's what most do.
Of course it could also be just crap Chinese metal as well ( they had no metallurgical standards over there of any kind back then). I built a 250 man tool shop over there, and forced them to only use Swedish steel on their molds, 80% of their manufacturing issues went away.
Actually I shouldn't be speculating on the problem (it's not my problem) and nobody is standing in line to hire my company to solve it, this is just a hobby to me. I trust Hobie has bright engineers who are on this.
Bottom line, fixing and re-enforcing the aluminum might not solve the problem, the problem is deeper.
Actually cutting that reduced dia off and replacing with a recessed shoulder bolt would be much stronger if you wanted to fix an existing pedal.
Hope this helps
Bob

edit:
After thinking about it a little more, you can repair that round pedal, and the repaired pedal will be much stronger than the original ( I think you would be fixing the root cause of the problem). If you drill a hole in the end and press a pin into the hole (press fit (possibly something like a dowel pin, or a drill blank)), the result will be much stronger than the original design.

Let me explain. If you take a 5/8 wooden dowel and turn down one end to lets say 1/4 inch dia (so it looks like the pedal but the 1/4" part would be much longer (only for testing), now tap on the side of the 1/4 inch part of the dowel, the dowel will snap cleanly right at the joint every single time easily. Now take a 5/8 dowel and drill a 1/4 inch hole in the end and press a 1/4 inch dowel into the hole. Now try to break it, it will take 5-10 times more force to break the 1/4" dowel. The reason is wood has a grain, if you have sharp corners stress is concentrated in those corners. Steel is exactly the same as wood.
Hope this helps
Bob

Sorry this is the way my mind works, and I can't turn it off. LOL


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PostPosted: Sat Apr 05, 2014 7:40 pm 
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Interesting stuff Fusioneng. I suppose I should do one of your fixes rather than just keep buying replacements, but I'd REALLY rather Hobie address the problem. And I think you hit the nail on the head - Chinese supplier. Sometimes it seems like they go out of their way to build crap.

I've included a picture of two of the little ends that broke off, and I shined a light across them to show the detail of the break better. I figured it might mean something to you.

Image


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PostPosted: Sat Apr 05, 2014 8:42 pm 
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What that picture tells us is, the grey area ( looks like peach fuzz) was already cracked at the factory so it was nothing you did or could do to create that. The pulled area was the only attachment from the factory for that shaft. This is typical of inferior metal, bad machining during creation, improper heat treatment ( if it is heat treated) and improper design. Could be any or all of the above.

Even best case scenario it will take Hobie 6 months to correct the problem, ( that not unusual, it's actually pretty standard in industry).
I don't want to see you get hurt again ( I'm diabetic and a bleeder ( because of medication), if I laid my leg open on one of those pedals I wouldn't make it back to shore.).
I'm certain the root cause of the problem is that round pedal shaft ( it comes from the factory fractured). I suggest you take some of your pedals to a machine shop and have a pin pressed into the end ( you can do it at home with a drill and reamer if your careful ( that is assuming it is soft enough to drill). Once you have a pin installed, the chain reaction shouldn't occur, bu to be on the safe side I would fill the end of the sq pedal with epoxy and wrap with spectra string, then epoxy the string together, just to be on the safe side. I also recommend you fix the other fatigue point ( in the pin hole in the center of the sq shaft) while you have it apart. Killing 3 birds with one stone. If it were me I would start with brand new pedals and shafts, hopefully you are getting these from Hobie for free because this is clear failure in manufacturing and should be totally covered under their warranty, no matter how many you break.
Bob


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