Crankset Decision

[Der_Kruscher]

Gang,

Mulling over a new build and the crankset part of the equation is yet to be figured out except that it will be standard gearing. I want something light that shifts well. I can get the following cranksets for about the same amount of dough; which should I go for and why...

DA 7800
Easton EC90
Sram Red

FWIW - the rest of the drivetrain will be 2009 Sram Rival. I could also reuse a Ultegra 10 crankset which would be the cheapest but most boring & heavy option :-) BTW - I don't have any preference aesthetically.

[regularguy412]

There are lots of different criteria to consider when picking a crankset, but I'd choose the one with the lowest Q-factor-- that is, unless, you are an exceptionally tall person or a person with wide hip bones (meaning: anatomy). I've always felt it important ( and more comfortable ) to try and get hip, knee and ankle in line and more directly 'over' the pedal. This also takes into consideration which type of pedal/cleat/shoe you use and how 'close' you can run your feet to the crank arms while still having a comfortable portion of your shoe over the pedal. A person with a wider foot might also be able to use a narrower Q-factor crank to get 'space' for the shoe to work without rubbing the crank arm. It's also helpful if you use booties over your shoes in cold weather, for the same reason.

I've not actually used any of the cranks you listed, but I have measured the 7800 crank after installation on a frame and it is a very narrow crank. It's in the neighborhood (+/- a few millimeters) of my 7410 crankset that takes a 103 mm BB spindle,, and that one is pretty narrow.

Mike in AR:beer:

[Der_Kruscher]

Good point on Q-factor. I'm 5'9" and my hips are proportional as I can tell. Will most crank manufacturers list Q-factor in their specs?

[regularguy412]

Good point on Q-factor. I'm 5'9" and my hips are proportional as I can tell. Will most crank manufacturers list Q-factor in their specs?

I believe you can find the specs with a little digging. The way the new-style cranks are made, the BB spindle is integral with the crank arms / spider. Formerly, Q-factor was somewhat of a combination of the splay of the crank arms themselves and the BB spindle length. I haven't measured 'new-style' triple cranks, but I'd have to believe the Q-factor is somewhat wider, just to accept the extra ring.

A person with short-ish legs on a small frame will be more sensitive to Q-factor differences. I've ridden behind very petite ladies and noted the severe angle caused by the combination of wide Q-factor and the particular style peda/cleat/shoe system they were using. They just couldn't get their feet close enough together. It appeared there was a lot of stress on the knee joint.

Tall people with wide hips can have just the opposite problem. They've needed a product called 'Knee Savers' just to get their feet far enough apart. One of my long-time riding buddies visited Andy Pruitt for a consult concerning hip pain. It was an alignment problem due to his Q-factor being too narrow. A wider Q-factor helped reduce his pain.

At 5'9", you shouldn't have a major problem with most of the popular cranks and their Q-factors. I'm 5'8" with slightly long-ish legs for my height. I prefer to use cranks with a Q-factor of ~142 mm. That's ~71 mm measured from the face of the crank where the pedal spindle meets the arm to the center of the downtube multiplied by 2. Cranks within about 6-8 mm of that measure work for me. Another factor to consider is the angle of your feet when clipped into the pedals. If you are a bit duck-footed, you may want a slightly wider Q-factor crank to allow room for your ankles to clear the end of the crank where the BB spindle is attached (since your heels will be angled closer to the frame than your toes). I have a pretty neutral foot position, so the narrower Q-factor works for me. Also, the type and style of pedal you use can have a significant bearing on how close your feet actually 'are' together.

Mike in AR:beer:

[Pete Serotta]

I would stick with the Dura Ace or SRAM....if both are the same length. You can not go wrong with either.

[sg8357]

What is standard gearing ?

Low q factor would be a Stronglight 49d, Sugino PX or TA Pro Vis.

I have a 49d on the Bates with Brampton pedals, with that combo
my foot is straight. When I ride a modern clipless setup I pedal
with my left heel angled away from the bike.

So this year I'm putting a 49d on my new Ebisu with clipless pedals
to see if my foot straightens out. French standard gearing of of 46/28.

Happy New Year
Scott G.

[ThirtyEast]

I would also tell you to look at the Fulcrum Racing Torq RS cranks, which are about the same price as DA 7800 right now in most places. It's the same as a Camp Record crank but fits chainrings with Shimano compatible 110 or 130 BCD rings. The Q-Factor is also a good deal smaller than DA cranks and others.

[bostondrunk]

I would also tell you to look at the Fulcrum Racing Torq RS cranks, which are about the same price as DA 7800 right now in most places. It's the same as a Camp Record crank but fits chainrings with Shimano compatible 110 or 130 BCD rings. The Q-Factor is also a good deal smaller than DA cranks and others.

Fulcrums are quoted at 145.5mm. Dura Ace 7800 is 147mm I believe. 1.5mm is not significant IMHO.
FYI:
http://www.fairwheelbikes.com/forum/viewtopic.php?t=5468&highlight=crankset