Adjustable Cranks

[nathan]

We've discussed adjustable cranks for Coker rides before and I have another progress report. Last October, I posted about the tests of a Murray prototype and the fact that I had ordered a set from High Sierra Cycle Center.

I've been using these cranks for a little while and they look promising. Take this with a grain of salt as I feel that I need to put 500 hard miles on these cranks before I really trust them. But so far so good...

Details:
Aluminum crank body, stainless steel adjustable pieces slides in and locks down with two hex bolts
Adjustment is 120mm to 160mm in 2.5mm steps
Adjustment takes <30 seconds, done with 3/16" hex
Taper fits Suzue hub perfectly - 113mm 2 degree taper
Cranks are 9mm wider than Bicycle Euro
Removing requires a long socket to reach the deeply recessed bolt - also many crank removal tools won't fit.
VERY high quality workmanship throughout.
Cost: see website, but it appears the sale they had last fall is no longer in progress so they are more expensive now. You can get them without the spider and with various lengths. Call and talk to the manufacturer as he is a good guy.

Test rides so far:
160mm: three rides, longest was 16 miles/1500'
120mm: two short 3 mile rides (including 18% climbs)
130mm: one 7 mile ride, 4 miles dirt, including lots of steep stuff

Now this is not much riding, but the results are very promising. Especially today, set at 130mm - it felt SO nice. My first impression trying these was that they somehow make the ride smoother. Maybe it's the fact that each pedal is now 9mm further out from the wheel? I am already using a wide hub, so it's pretty amazing that even wider feels better...

The aluminum part that bolts onto the hub fits better than any other aluminum crank I've ever used. Just tighten it up and it's good - doesn't need retightening after a ride or two - very nice. Not quite so nice is the fact that I am not able to use all my many pairs of pedals with these cranks. The threads just don't accept certain pairs (especially the Atomlabs I wanted to use). I took them down to my LBS and ran through with the tapping tool and can now use several, but not all pairs. No big deal I guess. They are of course heavier than normal cranks, but then that was obvious - sorry didn't weigh them yet. Another slight drawback is that you can't use a regular crankbolt remover to get at the bolt - it's deeply recessed.

There are a couple of photos in my cycles gallery and I've attached another image of them here, showing one at 120mm and the other at 160mm.

I know of several other efforts at adjustable cranks. Ed Mosiman made a beautiful set that works really well for Bronson on his Creative Gecko deluxe touring machine. Scot Cooper had a friend make a pair for him, but it had thin aluminum parts and he didn't end up using it. Plus of course the Murray Tour de Force ones I already mentioned (which I hope are improved from the early prototype I tried - but haven't heard). Five years ago, Daniel Hopkins tried using tandem cranks that had 3 holes at different lengths - they might actually be ok, but I really like the finer adjustment and avoiding rethreading the pedal every time (and not carrying a pedal wrench).

---Nathan

[U-Turn]

Interesting, Nathan. Thanks for the report! Do you have any idea how the small holes on the aluminum part are holding up? Are they widening at all?

Have you talked to the maker about the pedal compatibility thing?

Thanks again.

[Sofa]

one of his options is a 220mm crank!

I wonder if this idea might work with sort of a spring loaded cotter pin as opposed to the bolts, allowing for more of an on the fly, but still off the fly shift

Thanks for the report Nathan, these look like a great idea

[nathan]

I saw a pair of custom 210mm unicycle cranks High Sierra built for Gary Kanuch. He rode them last fall in the Mt Diablo Challenge. He ended up deciding they are too long (said they made him feel like he was pedalling in a square) but they are the most beautiful looking aluminum cranks I have ever seen in my life.

Sofa, I somehow doubt that a cotter pin arrangement that you suggest could really work. There has to be zero slop! Cool idea though.

No sign of problems yet in the holes in the aluminum pieces (but as I said, this is just a preliminiary progress report - 500 miles are required!)

I did talk to High Sierra about the pedal threading problem and he offered to do whatever it takes to make it right (including make new pieces) but I don't want to hassle with shipping etc - and they are working fine for me. I have enough pedal choices.

---Nathan