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Q factor question(9 posts)

Q factor questionlonefrontranger
Sep 25, 2002 1:28 PM
Anyone know the difference (if any) in Q-factor between Dura Ace cranks and FSA Carbon?
no but i do know the h-factor...hirevR
Sep 25, 2002 3:08 PM
..that's the HOT factor. FSA's are sooooooooooooo HOT!
want to touch the carbon weave..
Seriously though, one of my teammates rides'em and loves 'em.
FSA=121mm, DA=not sure, prob less than FSA(nm)5ive
Sep 25, 2002 5:04 PM
Sep 25, 2002 7:05 PM
Now that I know the FSA, the DA is easier to find. A friend asked, and since I no longer have ready access to shop manuals, I just knew someone here would have the answer.

Please post the Dura-Ace Q-factor....Eric_H
Sep 25, 2002 9:27 PM
....when you have it.
off the top of my headpeloton
Sep 26, 2002 12:52 AM
I think that the q-factor for the DA crankset is 115 or 116. Again, just off the top of my head and I could very well be wrong.

I've ridden both, and I have to say I really like the FSA's. The rings don't shift too bad either.
Very littlecyclequip
Sep 27, 2002 2:39 AM
I recently changed to the FSA - on a splined BB and noticed very little Q diff tho the chainline in the FSA is definitely further out than the DA
re: Q factor questionMXL02
Sep 27, 2002 3:19 AM
LFR- don't know the answer to your question, but now know what "Q-factor" is. Another pearl plucked from RBR. Thanks

PS- is this perhaps a more important reason to go with a double chain ring and mountain cassette, rather than a triple and standard cassette?
Sep 27, 2002 2:05 PM
Q factor is a main reason why roadie racers stick to dual chainrings if they can. If you're not used to the wider stance of a triple, it can tend to feel as if it's robbing you of power. But then roadie racers tend to be kind of the "princess and the pea" about stuff like this, and in real world terms I wonder if it isn't more perception than reality. I do know that to me, the combo of longer BB spindle length and correspondingly wider Q factor of my Centaur/TA 'cross crank setup (even tho it's a dual ring) feels a little "slower" and a tad flexier than my Record cranks on the roadies.

To add to your confusion, Q factor is actually based on a number of variables; BB shell width (I believe this is reasonably standard for roadie bikes anymore), BB spindle length, the style of BB (new, old, taper, spline, yadda, yadda) the crank itself, and of course the pedals one uses. Assuming the frame, BB and pedals are a constant (they are in this case), you can limit Q factor diffs to the crank itself, which is why I asked.

I posted this question for a friend, since I (amazingly) couldn't find the full DA technical specs on the web (bad google day, busy at work) and I haven't been to the shop yet to peruse the phone-book sized ShimaNO manual :p