This is not a weapon to deal a savage, savage beating, as evil as it may look. It is that part of the bike responsible for transferring all that human muscular strength and energy into mechanical kinetic energy. The cranks (well minus the pedals at the moment). Funny, I was going to say they convert all that wonderfully efficient human muscular energy, built on generations of evolution and refinement into horribly inefficient mechanical energy. But I thought I would Google my facts. Do you know human muscles have been calculated to only be ~20% efficient (26% at absolute most!).
Alas, I waffle. So, yet another great bargain secured here. TRUVATIV XX GXP Cranks. Worth $550, sold to the handsome man with the Heckler for $250. That's carbon you see in those cranks before you peoples!! May I also enlighten you to the fact these are Truvativ. Truvativ are owned by SRAM. So I stick to my lemming like commitment to SRAM. Do you remember a few blogs ago I explained the levels of quality in SRAM products? (Of course you don't). So my "level" has been X0. These are one level above, so officially these are the highest spec piece of kit I have procured so far.
Notice the 2 chain ring configuration so as to be compatible with my 2x10 speed running gear set up. Like every<bloody>thing else on a bike, there are multiple different configuration options/restrictions. Specifically put in place so a complete amateur like me can completely fuck things up. It is here I must admit to being a little too confident and bought a crankset before being "advised" it wouldn't be compatible (yep, Santocyclopedia to the rescue again). Luckily that order hadn't been dispatched by the supplier yet, so I was able to bail out.
So a couple of options.. firstly, the length of the crank. I currently run a 175mm crank length which is on the longer side of standard. But the giant has a very high clearance. I have been on a bike with long cranks/low clearance and it is like taking an F1 car 4WD'ing - the cranks bottom out on everything. So, aware that the Heckler will probably have a lower clearance, I have opted for a shorter crank. This is a bit of a risk, as I think I am better at pushing big gears slower, than small gears quicker, and the shorter cranks probably won't suit this style of riding as much. But, we'll see.
Chain ring size.. I went for a 28 tooth small and 42 tooth large. Fairly normal for a 2 speed configuration. You could consider this a "compromise" on a 3 speed configuration (ie: you would have a much smaller small chain ring, a middle ring, and a much larger, large chain ring to give you a greater range of gears). Even keeping in mind the extra gear on the back cassette (10 gears, rather than 9), I will end up with 20 gears, rather than 27. Why is the sacrifice worth it? 1. You rarely use all gears ESPECIALLY the extreme low and high on a 3x9 configuration 2. Weight and simplicity. For the type of rider I am, I have no concern over this setup.
Bottom bracket.. Links the crankset to the frame and provides the bearing's to allow the crank to spin freely. This is a "GXP" type crankset (SRAM's attempt to improve traditional bottom brackets). I've never used this before, so I will see if it makes a difference and stands the test of time. I had to ensure the bottom bracket would be compatible with the 73mm shell on my frame (note the mistake I alluded to earlier....). The BB was $32.70, so, being the honest chap I am will factor this into the progressive price score at the bottom.
Q-Factor.. this one is not widely known about, but one which is gaining a lot of understanding in the biking world as more often than not it is the one responsible for knee pain. It is the distance BETWEEN the pedals (so effectively how wide your feet sit on the pedals). It's something I don't know a lot about. These cranks have a low/very common QF of 166.
Still awake? You are? Refer then to some previous blogs...
Progressive costs:
Actual: $2088.73
Estimated: $1943.30
If RRP: $3892.98
Don't bend your Wookie,
Justin.
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