Cassette sizing
#26
Senior Member
Join Date: Jan 2010
Location: TC, MN
Posts: 39,505
Bikes: R3 Disc, Haanjo
Mentioned: 353 Post(s)
Tagged: 1 Thread(s)
Quoted: 20791 Post(s)
Liked 9,436 Times
in
4,663 Posts
#27
Senior Member
Thread Starter
Join Date: Feb 2019
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Liked 57 Times
in
40 Posts
Not a bad suggestion. Are you saying that it's possible to setup the front derailleur without cross-chain rub? I noticed when I'm cross chaining it rubs the cage. I figured that's just how it is when it's properly setup. My lbs does my adjustments. It feels correct. It's fast and shifts everytime.
#28
Senior Member
If the chain started rubbing the front derailleur after you made a rear shift, you could use the front shifter to nudge the front derailleur over so that the rubbing stopped.
Obviously your R7000 front shifter doesn't have a continuous range of motion like this. But it does have more than two positions. When you're on a chainring, you should be able to lightly click the shifter between two "trim" positions without shifting to the other ring. If everything is set up well, and you know how to make use of the trim, this should allow you to minimize rubbing.
#29
Senior Member
Join Date: Jan 2010
Location: TC, MN
Posts: 39,505
Bikes: R3 Disc, Haanjo
Mentioned: 353 Post(s)
Tagged: 1 Thread(s)
Quoted: 20791 Post(s)
Liked 9,436 Times
in
4,663 Posts
Not a bad suggestion. Are you saying that it's possible to setup the front derailleur without cross-chain rub? I noticed when I'm cross chaining it rubs the cage. I figured that's just how it is when it's properly setup. My lbs does my adjustments. It feels correct. It's fast and shifts everytime.
Edited to add: many aren't aware of the trim positions and your FD may very well be set up properly. Try it out on the next ride or just give it a tap while it's on the stand and see if the FD nudges over a bit.
#30
Senior Member
Thread Starter
Join Date: Feb 2019
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Liked 57 Times
in
40 Posts
You shouldn't have any trouble using all of your cogs when in the big ring. In the small ring, my chain will rub the inside of the big chainring if I'm cross-chaining, but a) this rarely happens - I use the big ring 95% of the time, going to little ring only as necessary and getting back out as soon as possible b) I don't have a Shimano crankset; their current cranksets space the chainrings slightly further apart to mitigate this, IIRC.
Edited to add: many aren't aware of the trim positions and your FD may very well be set up properly. Try it out on the next ride or just give it a tap while it's on the stand and see if the FD nudges over a bit.
Edited to add: many aren't aware of the trim positions and your FD may very well be set up properly. Try it out on the next ride or just give it a tap while it's on the stand and see if the FD nudges over a bit.
#33
Senior Member
Thread Starter
Join Date: Feb 2019
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Liked 57 Times
in
40 Posts
I took the plunge and am having my lbs install an 11-34. Hopefully the gear spacing is to my liking. It appears it's evenly spaced until the last 3 cogs, which I can see myself liking. The last cog is for after my legs have blown, and the 2nd to last cog is still a 30, which is better than the 28 I've been using.
#34
Senior Member
It is not. 11->13 and 25->27 are both 2-tooth jumps, but 13/11 is more than twice as wide a ratio as 27/25. Because the number of teeth on cogs must be integer, it's almost impossible for the spacing to be even. For instance, a 3-speed cassette with cogs of 12-18-27 would have even spacing, because each cog is 50% larger than the previous.
#35
Senior Member
Thread Starter
Join Date: Feb 2019
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Liked 57 Times
in
40 Posts
It is not. 11->13 and 25->27 are both 2-tooth jumps, but 13/11 is more than twice as wide a ratio as 27/25. Because the number of teeth on cogs must be integer, it's almost impossible for the spacing to be even. For instance, a 3-speed cassette with cogs of 12-18-27 would have even spacing, because each cog is 50% larger than the previous.
#36
Senior Member
In the "most used" range 15-25 the 11-34 is exactly the same as 11-28. And it gains a 27 and 30 reachable from the big ring, but looses the 14 and 12. Imo thats a good trade off for many recreational riders.
Bicycle Gear Calculator
Bicycle Gear Calculator
Last edited by Racing Dan; 08-23-19 at 01:17 AM.
#37
Senior Member
Thread Starter
Join Date: Feb 2019
Posts: 330
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 173 Post(s)
Liked 57 Times
in
40 Posts
In the "most used" range 15-25 the 11-34 is exactly the same as 11-28. And it gains a 27 and 30 reachable from the big ring, but looses the 14 and 12. Imo thats a good trade off for many recreational riders.
Bicycle Gear Calculator
Bicycle Gear Calculator
Edit: I went out for a ride today. The difference in shift-speed is slightly slower, but completely acceptable. I'm glad I went with the 34 cog. I don't think I'd even notice a 30 or 32. The 34 is just enough of a change for my legs to take note. I feel like I'm a wuss now when I select the 34 and spin up a hill I was getting used to getting out of the saddle or powering the 28.
Last edited by Princess_Allez; 08-23-19 at 10:55 PM.