Regarding Compact Cranks
I am considering a set of compact cranks. My rationale is that, while I don’t need the extra climbing capability, I also don’t really need a 53-11 gear very often and that a compact crank would actually give me more gears in a tighter range for the mostly flat city environs. Most of my riding around town, commuting etc. is done around 53-16, with the addition of a compact crank’s 50 tooth large ring in order to get an equivlent gear I could just go lower (I have an 11-23 cassette). Often times though, I find myself slowing mashing up a hill or overpass because the situation doesn’t exactly warrant a drop to 39 in the front, but 53 is too big. So I end up staying in a bad gear for whatever reason, maybe just laziness (but Nick you have hyperglide it doesn’t take any effort at all!(yes I know)).
Possible complications are that I have a braze on front “derail-her” which I heard often doesn’t work with compacts. While I realize I could saw that off and get a clamp on, I’m not yet in the business of hacking on european steel.
Also this post is largely an excuse to post the above pic.
Thoughts from the gallery?
2 Comments so far
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strait blocks dont shift as well as 2 tooth tooth differences. also, you could not do a compact crank and still put a 50 tooth big ring on, and really, a 42 tooth middle ring, and have a much more useful townie gearing.
yes i meant to say tooth tooth. say it aloud it makes sense…
i have anouther gearing idea, a super good one at that.
run a 50-49 up front, and a custom
12,14,16,18,20,22,24,26,28 in back. that way, you’ll half step it in front, so you can have perfect gear steps, 18 useable gears. i think. thats roughly what i am running, but i am using a 48/46 with a 12,16,20,24,28,30. read more about it here: In the days of 4- and 5-speed freewheels, 8- and 10-speed bikes were commonly set up with chainwheels that were very close in size, for instance, 46/49, or 47/50. When used with typical freewheels of the era, the difference between the two front gears was about half as large as the difference between adjacent gears on the freewheel. (One reason for this was that early front derailers couldn’t handle much more than a 3-tooth difference reliably!)
With half-step gearing, the larger shifts are made with the rear derailer, and the front is for fine tuning. This allows an 8- or 10-speed set up to have a reasonable range with fairly close spacing of the gears. One downside of half-step is that it uses all possible combinations, including those that run the chain at a fairly severe angle. This is not a big deal in an 8-speed rig, but is kind of marginal for 10-speeds. Another serious disadvantage is that every other shift in the normal sequence is a double shift (front and rear derailers simultaneously).
Half-step gearing is most suitable for riding in flat terrain, where shifting is rare. For bicycles with few speeds, it does allow finer gradations to get as close to the “ideal” gear for the particular wind conditions as possible.
Modern shift patterns use larger jumps on the chainwheels to select general ranges of gears, and fairly closely-spaced 7-or-more-speed clusters for the fine tuning. This greatly simplifies the shifting pattern, allowing constant adjustment to different grades in rolling terrain, with only occasional need for double shift.