Newest Drums for the Mirage Drive!

If you only replace drums and chains / idler. You would keep your original parts beyond that. You can also upgrade the sprockets and masts to the threaded versions.

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

I agree with Bob in some regards. It's really nice to have a spare Drive for certain applications.

As Matt mentioned, there are two separate "V-2" upgrades you can do. The more significant one is the sprocket and threaded mast upgrade. It involves 4 parts (of the approximate 94 parts of the Drive) and can be done for about $52 US or 10% of the cost of a new Drive. IMO, this makes a big improvement in reliability and should be done at the first sign of mast wobble or looseness. (Not referring to the old Stainless Drives here). A less expensive short term option is to epoxy the masts into the sprockets).

The "V-2" drum replacement involves 5 parts and costs about $127 US. This is a great upgrade but doesn't need to be done unless you have a specific reason (ie: worn drum, stripped pedal adjustment hole, broken cable).

With both upgrades in place, the Drive reliability should be virtually as good as a new Drive (if everything else is in good shape) for less than half the price of a new Drive.

I replaced the main stainless shaft some time ago and it is again showing signs of wear, but I have never had an issue with the fin shafts. Have been considering whether or not to upgrade?

As long as a failure isn't going to put you in any danger, If it ain't broke, don't fix it.

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Hobie Island Sailing since 2006

Worn shafts don't really hurt anything, but they should be lubed more frequently and can accelerate wear on new mating parts. Remember, all the shafts wear mostly on one side. You can double their effective service life by either rotating them or flipping them.

If you have a splined drumshaft, pound it out past the spline area, rotate 180 degrees and pound back in to re-engage the splines. Flipping the sprocket shaft places the unused top on the bottom for a new surface. If you want to mess with the idler shaft, flip it and file a new flat spot on it to lock in place with the Allenhead screw (don't over tighten, just snug).

In this way, you can upgrade your Drive more completely without purchasing new shafts.

Yes, but a good way to stop it from braking when out and needed, is to maintain it and change worn parts. My Mirage has not failed me yet and If I can help it stay that way, I will

Thanks for the tips Roadrunner, I will take a look as last time I just had a local engineer make a new shaft to remove the play.

My latest mirage drive went "Pop" today. I really hate that sound because 9 out of 10 times, it happens where the sea conditions are the worst.
Above photo: The pedal adjustment assembly pins do not extend all the way through the hole. Putting all the pressure on half the designed surface is going to yield bad results.

Above photo: This is what has happened to every one of my mirage drive unit drums. Hole reinforcement is a bandaid for the problem of the pin not extending through the hole like it should. Hobie engineers need to address the real problem. Now I can't let people who have shorter legs try out my kayak because, it is going to require removal of stainless steel bolts which I now have to install to replace the broken pedal adjustment assembly. Come on Hobie, just a few more design changes and you'll have a rock solid mirage drive unit!

Rnykster, how many miles does a drum last you? Looking at the other drum (where it has not yet failed), is the hole deformed? Does it always happen on the same side? Is the pin insert depth the same on both sides?

I've had this happen a couple times, my fault, pin not fully inserted I guess. Instead of buying new drums each time, I removed the drums, reversed them, switched right to left and reused. Only issue is the hole number decal is reversed. (Hole #7 is now #2)

I want to see if I can find a ss bushing to insert in adjustment hole to strengthen it, pretty much like Yakaholic did with a drum bushing.
viewtopic.php?f=11&t=35629

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Bob
Proud member Kayak Fishing Association of New York

Would it work better? Maybe, but the plate is a HUGE change in strength. We have issues with a longer pin, The lever system limits the total length. The tapered end required for easy insertion also limits the surface contact possible. Too long a pin would extend between the drums as well.

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

Additionally, if the pin were longer, it would not be fully retractable. As you can see here, it is currently at the maximum length that allows retraction:


So in order to accommodate a longer pin, the retractors would have to be redesigned next. BUT existing space available for retraction is limited by the gap between crank arms. There has to be adequate clearance for drumshaft wear as well. As you can see here (with this well used Drive), there is no available space:


There are a couple of ways to solve that problem as well, but each of those creates other issues.

Or, you can put a Stainless insert in the drums, as Hobie has done.
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Rynksters problem happened suddenly, or did it?

As the pin pulses against the drum over time, the material between holes begins to migrate. This may become visible after several hundred miles of use, depending greatly on the intensity at which you regularly pedal. Notice in the following picture the slight elongation of hole #2 and "D" shape of hole #3 as the material shifts forward:

This is not problematic as long as hole #3 is still available for pin insertion (That's one reason for the design margin in the hole size vs pin size).

After a few hundred more miles (again depending on several factors), the bulge starts to look like this:


At this point, there is considerable stability loss in the hole and the drums should be reversed or replaced. Further use risks Rynkster's "sudden" result.

Frequent inspection is the key to avoiding these unnecessary and untimely events. In this case, it only becomes obvious by moving the crank arm and examining the hole. It's easy to overlook!

Would longer pins (if feasible) solve the problem? IMO, no -- they would only delay it at best. Would metal sleeves in the holes solve it? IMO, no, for a variety of reasons (thinwall pins would ovalize, then fall out, leaving less material between holes setting up a rapid failure). Does a stainless insert solve the problem? IMO, (so far) yes. The pin holes should maintain their integrity well beyond the wear limits of the drumshaft hole.

The pins that only extrude 3/4's of the way into the holes have caused part failure in 100 percent of my pedal drives. The hollowed pedal crank shafts experience twist which makes the pin go even shallower.

On those pedal drives, when replaced with a bolt that extrudes completely through, there have been 0 percent failures. Based on my experience, IMHO, longer pins would eliminate the partial shearing of the material between holes.

I think you're absolutely right that longer pins would improve the longevity of the drums, but these new stainless inserts should render the problem obsolete. Time will tell.

The bolt-through option is a good alternative in many cases. But I wouldn't go so far as to say there have been 0 percent failures. Here's one I installed a few years ago (2006) and the final outcome not too much later:

It did last longer than the pin though. And to be fair, these were the less durable V-1 drums.

Good questions. I do not know how many miles it is before a drum fails exactly, but as a general rule, the newer drives start failing before I ever reach 1000 miles. Can't see the holes right now, they all have bolts in them. Can't remember if all the failures were on the same side - I don't have the old drives anymore and never kept records that accurate. Can't comment on the pin depth - both my drives now have bolts in them. Sorry.

That was 0 percent failures for me, not for everyone. So far I've been fortunate to have not experienced a complete breakage between the holes like you. Keeping my fingers crossed...