Ken Kifer, help me clarify some of his ideas please!
01-02-06, 04:20 PM
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In reply to Black Bud:
– Ken Kifer's latest touring bike used the current technology of the time, which is a 5-cog freewheel. In theory, he could have used a wide range double with a wide range 9-speed cassette. For instance, he could have used a 44-26 double and a progressive cassette with 12-14-16-18-20-23-26-30-34 (let's pretend that stuff is easily available) and he would have similar ratios available: from 20.6 to 99 gear-inches.
– The problem many doubles represent is that oftentimes, the most useful ranges are at the top end of the small ring and at the bottom end of the large ring. Depending on wind and terrain, one may need to double-shift often in that area. A triple avoids it.
– The current philosophy promoted by Shimano gods that we should avoid oblique chainlines has been carried to the extreme because of the lack of flexibility of STI. If you use a downtube or barend shifter, or an Ergo integrated shifter, it's very easy to use the large ring with more than 3 or 4 cogs: you just trim a bit the derailleur. With a friction shifter in front, it's possible to use the granny with 5-6 cogs, the centre ring with all cogs and the large ring with 7 or 8 cogs. Chainline might not be "ideal" with all of them, so I wouldn't use such combos for 100 km, but for short periods, why not? As long as the front derailleur is trimmed properly.
– Finally, I always have a problem with people who want to avoid a triple at all costs. What's the problem: weight? Who cares about a few grammes for touring! Slight delay when shifting between rings? Again, what's a 2-3 second delay when touring! Not using it very often? Again, when touring, it's important to have gears that will avoid undue strains. While a racer wants to get uphill as quickly as possible, a tourer usually prefers to get uphill as calmly as possible. One wants to save time, the other wants to save the day. Both are valuable objectives, but after 100-150 km with a headwind and loaded panniers, it's really nice to have that granny when you need it, even if you use it only once or twice during a tour.
– Ken Kifer's latest touring bike used the current technology of the time, which is a 5-cog freewheel. In theory, he could have used a wide range double with a wide range 9-speed cassette. For instance, he could have used a 44-26 double and a progressive cassette with 12-14-16-18-20-23-26-30-34 (let's pretend that stuff is easily available) and he would have similar ratios available: from 20.6 to 99 gear-inches.
– The problem many doubles represent is that oftentimes, the most useful ranges are at the top end of the small ring and at the bottom end of the large ring. Depending on wind and terrain, one may need to double-shift often in that area. A triple avoids it.
– The current philosophy promoted by Shimano gods that we should avoid oblique chainlines has been carried to the extreme because of the lack of flexibility of STI. If you use a downtube or barend shifter, or an Ergo integrated shifter, it's very easy to use the large ring with more than 3 or 4 cogs: you just trim a bit the derailleur. With a friction shifter in front, it's possible to use the granny with 5-6 cogs, the centre ring with all cogs and the large ring with 7 or 8 cogs. Chainline might not be "ideal" with all of them, so I wouldn't use such combos for 100 km, but for short periods, why not? As long as the front derailleur is trimmed properly.
– Finally, I always have a problem with people who want to avoid a triple at all costs. What's the problem: weight? Who cares about a few grammes for touring! Slight delay when shifting between rings? Again, what's a 2-3 second delay when touring! Not using it very often? Again, when touring, it's important to have gears that will avoid undue strains. While a racer wants to get uphill as quickly as possible, a tourer usually prefers to get uphill as calmly as possible. One wants to save time, the other wants to save the day. Both are valuable objectives, but after 100-150 km with a headwind and loaded panniers, it's really nice to have that granny when you need it, even if you use it only once or twice during a tour.
01-02-06, 09:45 PM
#27
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Originally Posted by Moose
How do you make a 15 speed drivetrain without using a triple?
02-07-06, 04:43 PM
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according to This Page he used 52-48-24 and 14-17-21-26-32. In his opinion, a 52-47-24 would be better, but he never got around to setting it up. These gear ratios would produce the following gear-inches with a 27 inch wheel. Presumably the gear he didn't use is the big-big (46"), but he had no problem with appropriate use of small-small.
(this was done on MS Paint, so be nice!)
The upside is that he can find an appropriate gear from most situations. The deal-killer for me is that in that you have to know which ring/cog you're on in order to shift. I tried a similar setup on an 18 speed, and I could not keep track of the complicated shifts. I'll stick with a jumping (aka "continuous") gear setup.
He rode far enough to know what works for him, I can say no such thing about myself. If the above setup works for you, you have Ken's blessing, and mine.
(this was done on MS Paint, so be nice!)
The upside is that he can find an appropriate gear from most situations. The deal-killer for me is that in that you have to know which ring/cog you're on in order to shift. I tried a similar setup on an 18 speed, and I could not keep track of the complicated shifts. I'll stick with a jumping (aka "continuous") gear setup.
He rode far enough to know what works for him, I can say no such thing about myself. If the above setup works for you, you have Ken's blessing, and mine.
Last edited by Ceiliazul; 02-07-06 at 04:50 PM.
