Doing the gears all wrong...
pibrahim
Posts: 17
...apparently.
I did the AMR Castle 100 over the weekend (100k, not the 100 miler), at the end I asked the bike mechanic why I had a bit of difficulty in shifting and why my chain was also rattling around a bit. He asked me why I was in the 50 ring and the biggest cog on the cassette (I'm on a Cannondale Supersix 105 - so I assume this is the 27). I didn't really have an answer, that's what I tend to cycle in - I generally keep it in the 50 and use the 3rd or 4th easiest cog on the cassette (I guess 22 or so?) on the cassette, and on hills I keep it in the 50 and then drop to the easiest (the 27). It's only on the really tough hills that I drop to the 34 ring at the front.
Anyway, it sounds like that's all wrong. He suggested I use the five easier gears at the back with the 34, and the five harder gears with the 50. Is that right? What should I be using for flats, the 34 or the 50? And how does it work, shifting from one to the other? If I'm going along on, say, the fifth cog on the back and it's a bit too easy and so i want to shift up one to the sixth (i.e. the first of the five 'harder' ones he talked about), if that also means I need to shift from 34 to 50, is that not going to be a massive shift? Am somewhat confused now!
I did the AMR Castle 100 over the weekend (100k, not the 100 miler), at the end I asked the bike mechanic why I had a bit of difficulty in shifting and why my chain was also rattling around a bit. He asked me why I was in the 50 ring and the biggest cog on the cassette (I'm on a Cannondale Supersix 105 - so I assume this is the 27). I didn't really have an answer, that's what I tend to cycle in - I generally keep it in the 50 and use the 3rd or 4th easiest cog on the cassette (I guess 22 or so?) on the cassette, and on hills I keep it in the 50 and then drop to the easiest (the 27). It's only on the really tough hills that I drop to the 34 ring at the front.
Anyway, it sounds like that's all wrong. He suggested I use the five easier gears at the back with the 34, and the five harder gears with the 50. Is that right? What should I be using for flats, the 34 or the 50? And how does it work, shifting from one to the other? If I'm going along on, say, the fifth cog on the back and it's a bit too easy and so i want to shift up one to the sixth (i.e. the first of the five 'harder' ones he talked about), if that also means I need to shift from 34 to 50, is that not going to be a massive shift? Am somewhat confused now!
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Comments
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Oooops - this was meant to be in the Road Beginners section. Could a mod please move this?0
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It's a matter of gear inches and crossing the chain. The more you cross the chain eg 50/27 the chain is diagonal to the chainline. Look at a gear chart and see where the gears match (or nearly) and then work around that. A 50/27 might be the same as 34x18 so it maybe better to ride in that. As to what you should be turning that's up to you. Most people are overgeared anyway imo and would be better running smaller rings eg 48/36 0r even 46/36,46/34 with eg 11-25.12-27. It depends on the terrain and your fitness of course.M.Rushton0
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Chains arent very efficient when run at angles. So big - big, or small-small are no-nos.
If you can get a copy of Richard Ballantines Bicycle Book - theres lots of useful advice in there. I loved it as a kid starting out.0 -
Just shift into the smaller chainring earlier. If the terrain is flattish undulating, you might want to drop into the small chainring and simultaneously shift into the next smaller cassette ring to avoid an overlarge cadence change. It's not really as simple as the mechanic suggests though I think if you do what he says you'll end up overlapping the gears anyway - which is what you should do.
It sounds as though you really need a standard chainset rather than a compact. In hillier country, the endless changes of gradient tend to mask the feeling of the big jump between chainrings.Faster than a tent.......0 -
Never ever ever drop to the 34, don't listen to the haterz0
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It's written around a MTB triple, but the principles are sound for a double too:
viewtopic.php?f=40043&t=126471170 -
Thanks for all the advice guys. Is it just the absolute extremes I should avoid then - i.e. 50 and 27 is a no-no but, for instance, 50 and 21 would be fine? Also, do most people use the 34 or the 50 on the flats (or is this simply a question of individual fitness really)?0
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Which ring you're in on the flats depends on how fast you're going. Keeping a decent cadence for whatever speed you're doing is what matters.
I tend to avoid the 2-3 lowest cogs on the cassette when I'm in the big ring, and avoid the 2-3 highest gears on the cassette when I'm in the small ring. I can get the same ratio with a straighter chainline by changing from e.g. 50/25 to 34/17.
Crossing the chain won;t destroy anything immediatedly, but it's best avoiding0 -
Easy rule of thumb for a compact 50/34
Below 17mph bottom ring
Above 17 mph on the 50
Can show on a chart but that's a bit nerdy0 -
Some good points/advice above - the extreme chainlines are a good way of making sure your chain spontaneously combusts unless you are particularly fastideous about replacing chains/cassettes.
If you rarely use the easiest of gears and feel as though there's too much of a jump between the two chainrings, consider a 36 inner. As suggested, a 36/48 may be more appropriate, but there are no rules, just personal preferences - if in doubt, don't throw too much money at it and just work with what you have until bits need replacing and then experiment0 -
Put your bike in a workstand, and shift the chain into your extreme 50x27 combination. Walk round the back of the bike, shut one eye and look down the length of your chain. The conspicuous lateral deflection should tell you your chain is well outside its comfort zone.0
