# New cranks



## alienator (Jun 11, 2004)

It's Christmas in Tucson...well, or so it's seemed since my THM Claviculas came in today. I fondled them for quite some time, then I wiped off the fondle juice. I removed the FSA Carbon Team cranks and the Shimano Ultegra BB, cleaned 'em up and weighed 'em. All tolled the old crankset w/ 53/39 chainrings and BB weighed 842g. The Claviculas w/ their integrated CF BB, cups, Stronglight CT2 50/36 chainrings, and SRP chainring bolts weighed in at 562g. So, for only a few pesos, I shaved 280g (0.616 lbs) off the bike. FWIW both cranksets have 175mm crankarms.

I gotta pickup wifey from work, then I'll finish the install.

Pics to follow.


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## hardride27 (May 27, 2006)

alienator said:


> I gotta pickup wifey from work, then I'll finish the install.
> 
> Pics to follow.


This is a set-up, right?


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## Juanmoretime (Nov 24, 2001)

Sweet! I'll look forward to the pictures and more importantly, the ride report.

Enjoy!


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## omniviper (Sep 18, 2004)

PIC PIC PIC!! cant wait!


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## alienator (Jun 11, 2004)

Ok, here are some interim pics. 

First pic shows the beauteous things. Freakin' works of art to look at. 

Pic two shows the novel crank arm orientation. People try to fix the deadspot in the crank rotation with oval rings and funky cammed crank arms, but THM went out of the box. With both crank arms hitting the power phase of the stroke at the same time, power in that phase is doubled. Then both legs get to rest during the off power phase, so rest is doubled. And as we all learned in algebra, 2x + 2x = 4x, which means these cranks offer a 400% increase in mechanical efficiency!!! 

Pic three: I stared at the carbon fiber bottom bracket axle for three hours to see if it would spontaneously explode.....like carbon fiber is known to do......but it didn't. So I feel pretty good that it won't. Just in case, though, I'll be keeping the crankset in a bunker in the back yard, at night.

Pic four: speaks for itself, donut? 563g (as opposed to the erroneous 562g that some reported earlier.). Not bad at all. Not bad at all.

It wuz dark when I did the install, so I don't have finished pics, yet....BUT.....the bike is now exerting a hefty 15.3 lb force on the Earth.


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## cadence90 (Sep 12, 2004)

Wow! They're stunning!  
We (you) have been waiting so long I can't remember if it's Xmas 1999 or Xmas 2012. Either way, it's a good thing the post knows which month Xmas falls in Tooson.

Regarding the output data, however, I noticed a _slight_ error. Your formula is essentially the PowerCranks formula and is _spot-on_ for those (the Bobby J autograph Rotorhead Ovaltines are actually slightly less efficient). What you missed is the fact that the THM are _bonded_ in that configuration, as opposed to the gorilla-arm swinging PCs, therefore there is NO loss of effort due to _either_ friction or inversional crosswind drag on the upswing. Therefore, the formula is really 2x + 2x + 1.75x - (- 0.3x) = 6.05x, i.e. a whopping 605% improvement! A minor oversight on your part, due to oxygen-deprivation I assume. It's common and it passes.

BTW: This formula, elegantly, does _not _take into account madcow-induced wait-time stress risers. HTH!

PS: No worries on that nasty and tricky spontaneous carbon combustion w/these. I have it on good faith that this is special defence-grade CF, impervious to all substances known to man, except Ex-Lax.


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## Juanmoretime (Nov 24, 2001)

Alienator, also a good choice on rings. I love my CT2's and I think that you will find them to be some of the best. I would take it your using a KMC X10SL gold chain?


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## foz (Sep 30, 2004)

i saw a set of these a couple of months ago and they were very very nice... the 1000+ euro price tag was a bit hard to stomach though. what about some carbon rings? they won't last long, but they would look even sweeter than the ones you've got!

foz


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## RocketDog (Apr 9, 2005)

One of the crankarms is longer than the other, see pic 4. This will cause you to eternally ride in counter-clockwise circles of ever decreasing diameter (waltzing bike syndrome, WBS) until the radius of your circle approaches zero asymptotically. If you are pedalling at your normal 450 watts the vortex created by this will likely swallow all of Arizona, but fortunately no one really cares about old people anymore anyway.


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## alienator (Jun 11, 2004)

Hmmmm, Rocket Dog, that spiral looks identical to the path that most of the elderly drivers here follow.

Now, cranks.........I've put a hundred mile on 'em, and I've found they work. No squeaks, rattles, or anything that sounds like "humuda humuda humuda humuda humuda humuda humuda humuda humuda humuda humuda......" One odd thing I have noticed is that each of my pedal axles seems to describe a circle, as I pedal, and the circle for each of the pedals seems to always be located in a plane parallel to the plane of the rear wheel. Very strange.

Stiff? If you say so, but I do know they've made my power output skyrocket: now my power output is peaking at 28 watts, and I can hold that 28 watts for nearly 23 seconds. Prior to the cranks, I was only putting out a measily 27.3 watts. Accelerate? Man, I got off the bike, and it took off, speeding up the hill next door. Now I have to keep it on a leash.

My wife says that since I got the cranks, I look more tan and more fit. And while chicks have always dug me, 7 or 8 women stopped me today to say that now they dig me an unholy amount, especially compared to the hellacious amount they dug me before I had the cranks.


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## alienator (Jun 11, 2004)

Here's a shot of the cranks on the bike. The rest of the pics is here.


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## cadence90 (Sep 12, 2004)

Super! Tres, tres _chic_! :thumbsup:


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## alienator (Jun 11, 2004)

cadence90 said:


> Super! Tres, tres _chic_! :thumbsup:


Muy gracias.


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## pantag (Jul 21, 2006)

Alienator, it looks awesome. But how come you switched to a compact crank? Your area is hilly?


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## alienator (Jun 11, 2004)

pantag said:


> Alienator, it looks awesome. But how come you switched to a compact crank? Your area is hilly?


Well, compact cranks aren't the entire drivetrain equation, but it is hilly where I live. The desert around Tucson is anything but flat. We've also got mountains on all 4 sides of the city, with tough climbs in 'em. Right now I've got 50/36 on the front and 12-25 on the rear. 50-12 should be sufficient for darn near anything. Also, I'm a spinner, pedaling between 95-105.


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## Guest (Aug 17, 2006)

I made the switch to compact when I set up my latest ride and after crunching the numbers I went with the 50-36 as well,and I am liking it too.

I live on the coast so I don't get to climb much at all so I am running 11-23 in back. I have only gotten to ride the compacts for a couple of weeks so far but its working well for me.

Love the new cranks, thanks for posting the pics, I will have to look into those for my next build.


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## pantag (Jul 21, 2006)

Interesting... It looks like the compact cranks are getting more and more popular. I didn't think they would last long...
I have to try my 53-39 | 12-25 on my new Onix when it arrives. I come from a triple | 12-25 and I am hoping I will not have to change anything.


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## omniviper (Sep 18, 2004)

i dig! i dig!


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## Mdeth1313 (Nov 1, 2001)

alienator,
are those speedplay x/2's on your bike? I would've thought you'd be riding x/1's, although you might be outside the x/1 weight limit?


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## alienator (Jun 11, 2004)

Mdeth1313 said:


> alienator,
> are those speedplay x/2's on your bike? I would've thought you'd be riding x/1's, although you might be outside the x/1 weight limit?


They're x/2's. The spindle is a touch longer on the x/2 than on the x/1, and that works best for moi.


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## Wyliekylie (May 17, 2006)

alienator said:


> Here's a shot of the cranks on the bike. The rest of the pics is here.


After all of that you put them on wrong to get the 400-600% increase in efficiency.........


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## glia (Jun 29, 2003)

Who sells the THM Claviculas cranks?


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## alienator (Jun 11, 2004)

glia said:


> Who sells the THM Claviculas cranks?


Fairwheel Bikes does, but don't expect to get them real quick. The current wait for Claviculas is in excess of 24 weeks.


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