Drive Unit, Spare Parts, and Tips

Drive adjustment slip.

Yes, we have seen some adjustment pins slip in the drums. Seems they do not fully engage (seat into) the drum at times and when pedaled hard, as you do, they slip and tear some of the drum material. We are nearing completion on a re-design of the drum that will add some stiffness along with some additional material around the pin holes. The new drums will also ease some bend issues we have on the cable / chain swedges. So far so good in testing the new drums (and some new chain assemblies) are far outlasting older parts in continuous cycle testing we are doing... I think I heard 3 times as long and still going.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

It is good to hear you are continuing to test and strengthen the design. If you ever need someone to put your equipment to the test, let me know. If I can't break it or wear it out, no one can. <Grin>

Rynkster, When we get pre-production samples...That would likely be a good idea. Perhaps we can get one of your drives set up with some new parts? Let's keep in touch. This is still a few months away I would bet.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Like Rynkster, I was out screwing around the other day -- chasing boat wakes; had a very similar experience.



I suspect there are a couple of other factors that are contributing to this problem. The Turbofins are allowing more pressure on the drive components, which is stressing parts that have not been problematic in the past.

The precipitating event causing the drum failure is, IMO, the new style crank arms. Because they are hollow, they are subject to more flexing than the older arms. As they flex, they pull away from the drum, partially extracting the adjustment pin in the process. Looking at both drum failures, the material fails near the surface, indicating the pin was pulled out to that depth.

The pic below shows the differences between the new and the older arms.



The new arms do not have the strength or the rigidity of the older versions. If you notice the lower left corner of the hollow arm, you can see a crack. It extends the full length of the arm (This happened on the next outing, next boat wake -- just popped!).

These type of failures were virtually unheard of with the standard fins, because the they didn't offer enough resistance to overstress these parts. They still should be relatively rare, since most users aren't pedal mashers!

The new drums will surely solve some problems, but the crank arms should also be revisited to reduce drum-destroying flexing and outright arm failure.

I have re-mounted the Turbofins on an older drive and noticed virtually no flexing with the solid crank arms. Since Hobie still has these arms available, they would be a fantastic bargain for anyone who can mount their own bicycle style pedals!

Hi Ya Roadie
Any idea what the model number is on the older style soild crank arm? I may yank the new cranks and install these if thats gonna help. I just checked my drive units and noticed some ovalizing of the holes in the drum unit. I dont know if this is how the trouble starts or if this is normal wear but will "mic" the hole diameter Monday and monitor any further wear. It looks like the space between holes is getiing closer and could possibly lead to eventual problems. Is there a certain time frame warranty on the Mirage units
-kepnutz-

Hi Kep,

The surest cure, as Rynkster has done, is to bolt it up. I've done the same:



Unfortunately you lose the quick adjustment feature, but probably don't need it by now.

The only problem with the older crank arms is that your current pedals won't fit and Hobie has no older ones left, so you'd have to purchase some sort of bicycle pedals. Then, too, if your drum is excessively warped, it could still fail.

The failure is sudden and under "full throttle". Excessive gap between the drum and arm, combined with crank arm flexing, simply withdraws the pin to where there is insufficient material to hold it in.

In the short term, Hobie's simplest fix, IMO, is to simply extend the length of the pin!

With an overlay of .125" Stainless Steel Plate on the drum for sheer stability and solid pin engagement.

2 cents.

If you are going to bolt up the arms to the drums be sure to use a "shouldered bolt" so the bolt threads do not chew up the plastic drum.
Like this...



M8x45 bolt fits good, the washers are 1 1/4" fender washers with a 5/16ths hole, nylon lock nut. Everything is stainless steel. You do not need to over tighten anything, just sung it up and be sure you can rotate the bolt with finger pressure.

The limiting factor to the pin length is the squeeze lever. It can only pull the pin out so far. I believe it is maximized.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Yes, I finally figured that out. As it turns out, it would have been a very short term fix.

If it isn't one thing, it's another! Went out to a lighthouse 6 miles from land in open waters leading a group of kayakers. The wind picked up a little creating some nice riding waves. As their worry about staying upright increased, I was staying high and dry, feeling very stable in the Outback.

But, on the return trip as I chased the first wave to ride it, there was a disheartening sound of "Snap," along with loss of control. The chain cable snapped at the place it was crimped. (This is the second time I've had a cable snap.)

Matt, can we get a rust proof cable or one that is sealed? My cables are apparently rusting at this delicate crimp point.

Knowing how prone the pedal drive units are to failure, it only took a few seconds to swap out the broken drive unit with the backup drive unit. The swap took place so qucik none of the other kayakers even knew I had a breakdown. Don't ever leave home without your spare unit.

Sorry to hear about your drive unit breaking. Thought for a while it was just my drive unit breaking.

I have noticed quite a bit of twist in the new pedal units. (Not to mention the lousy pedal design with hard plastic and sharp edges that dig into the feet.) The end cap disappeared after my first use leaving the view of the hollow crank arm. The pedals and crank end caps are examples of poor design using a cheap components.
In my opinion, instead of making cheaper parts, Hobie should be strengthening the the drive unit to handle the more powerful fins. I'd really hate to see someone break down at a bad time, like being left without control near big waves and rocks near a shoreline.

Not sure about the rest of you, but I'd pay more for higher quality components that don't break.

The cables are stainless already. We are doing a re-design of the drum and cable lengths to take the crimp point further away from the bending point. The cables and chains will also be of a higher grade stainless and a better crimp system. We just cycle tested some and they lasted 3 times as long (one failed after about 700 miles use). On that one... a chain link failed.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

We REALLY do hate using paddles don't we!

As noted in my post above, we are working on more changes and are trying to make things better and stronger... not cheaper.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

I just took delivery of a Turbo Kit for the Mirage Drive. It is a worthwhile upgrade in and of itself but it will also give you a "spare parts kit" consisting of two rods, two flippers and retaining pins and clips.

It is certainly possible to bung the drive to where it is non-functional. This happened to my wife's Outback on a short trip on our river. I was in my Adventure and pulled her drive to discover that one mast had been bent so severely that when it rebounded the mast pierced the neoprene sleeve that it rides in.

Still, I could have repaired it on the river if I'd had the right tools. Here's what is necessary at a bare minimum:

Proper size Allen Wrench to unlock mast
Small needle nose pliers and a dainty jeweler's screwdriver, (useful to remove and reseat clips - fingernails don't work very well - Ouch!)

With these tools you can remove the fin and mast - then use your knee to bend the mast sufficient for clearance. Do a better job of straightening in a vise.

With the replaced mast/fins when installing Turbo Drive you could simply replace the problem unit with no necessity to straighten. Probably replace both as there is a difference in length/size between the standard units and the turbos.

My dealer said "not a big deal" about the Turbo Fins but I have to differ. The rest of this will be repeated as I'm going to start a thread on Turbos with a couple of questions.

The turbo mechanism is a better unit than what came not even considering the speed increase. It has machined set screw slots rather than the primitive grinder slot that came with the unit. Additionally it has a "tension" mechanism built in that adjusts for rigidity and increases speed with additional tension. I assume that the downside is a greater possibility for damage when hitting an obstacle with a stiff flipper.

There is a noticeable speed increase for me. In bicycling terminology there are "spinners" and "grinders" and I was a "grinder". Big legs and big leg muscles with a penchant for slower cadence/higher gear. Samo Samo with the mirage drive - I don't enjoy having to up the cadence in order to go faster - I'd rather push harder.

The turbo fin has approximately the same shape but about 2" additional length. I am getting a better workout now because I have to push a little harder and that's good. It's still easy enough that I'm fantasizing about a little bit more surface.

How about a SUPER TURBO DRIVE, Hobie?

One of my drive units has an annoying "click" that takes place when making the push on the left side pedal. I've analyzed the chain and adjustments but can't find anything obvious. I'd appreciate any theories or advice on how to take this click out.

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Steve G. Garrison