Front shifting with close ratio cassette

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vinuneuro
Posts: 103
Joined: Mon Mar 06, 2017 10:34 pm
Location: Chicago

by vinuneuro

I currently have 50/34 + 11/32. Given the wide cassette, I'm only 3 cogs away from the right ratio when I need to shift chainrings. Looking at the gear calculator though it looks I will be 5 cogs away from the right one with a front shift with 11-25.

How do you handle this efficiently with manual groupset (non-Di2)? Going down the cassette is particularly a challenge with Shimano shifters since you can only go one at a time.

By far the best gear calculator I've ever used: Bicycle Gear Calculator

50/34 + 11/32 (top), 11/25 (bottom)

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evan326
Posts: 480
Joined: Wed Sep 14, 2016 8:51 pm
Location: RVA,USA

by evan326

Fast fingers from playing too many computer games I guess? :noidea:
Also only a small difference, but you've got two different tire sizes set on there.

by Weenie


martinko
Posts: 360
Joined: Fri Dec 06, 2013 9:08 am
Location: Slovakia

by martinko

Same, no problem shifting down fast on Shimano as well as SRAM. Just click fast.

Hexsense
Posts: 463
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

When you move between rings, you don't go to the same ratio but rather, the next ratio.

I hate 12-25 with compact chain ring.
It require 4 shift when moving between rings to get close enough for the ratio, or shift just 3 time and get a big change in cadence.
However, 11-25 or 11-26 or 11-28(sram) and compact chainring require just 3 shift and it is fine, same as 12-25 with standard rings.
Best would be compact chainring with 11-28(shimano) or 11-30 which need only two shift in the back to compensate.

picture with 12-25 vs 11-28(sram). 12-25 require 4 shift to get close enough. 11-28(sram) require 3 shift to get plenty close.
20901739_10154913538422061_7540703966723165806_o.jpg

pdlpsher1
Posts: 1543
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Here's my simple solution. When going from big to small, delay the shift until the chain is riding on a fairly large cog. The larger the cog the wider the ratio on the cog next to it. So when you shift you don't need as many shifts on the rear to match the cadence. When going from the small to the big ring isn't as problematic. If you have a Shimano lever, one full sweep of the lever changes three gears at once on the back.


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Hexsense
Posts: 463
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

pdlpsher1 wrote: If you have a Shimano lever, one full sweep of the lever changes three gears at once on the back.


Agreed, 3 gear shift is enough for 11-25 with compact. So OP should be fine.
It's only 12-25 and compact that need 4 gear shift.. the only combination that is annoying for me.

by Weenie


2lo8
Posts: 440
Joined: Thu Mar 31, 2016 10:32 am

by 2lo8

I try not to run 16t chainring differences. I also set it up with enough gear overlap that I don't have to constantly change between chainrings, and if I am, it's probably extreme rollers and the big jump is a good thing.
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