Changing from 10 to 11 spd on tri bike

Jun 29, 20 12:38

Post #1 of 15 (1845 views)

Hi, I'm currently on a 53-38 (yes, 38 not 39) and 11-28 10 spd in my tri bike, and will change to 11 spd. 160mm cranks on that one.

I already have an 11-28 11 spd cassette available from my road bike (that is 53-39). Road bike has 170 mm cranks.

Should I get a different cassette just to have different options? maybe a 12 with 30, 32? or a smaller one, 25 or 27?

Also, how do I know if I need a short cage, medium, large?

The groupsets will be Ultegra mechanical so I can swap the cassette between the two bikes.

I train and compete in varied terrain, so I would like to have options, maybe a "fast" cassette and a "climb" cassete?

Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jun 29, 20 13:09

Post #2 of 15 (1805 views)

"Should I get a different cassette just to have different options? maybe a 12 with 30, 32? or a smaller one, 25 or 27?"

Depends on where you will be riding.

"Also, how do I know if I need a short cage, medium, large?"

A short cage can handle up to 28 teeth.

A medium cage can usually handle up to 34 teeth.

Road rear derailleurs aren't available with a large cage.

Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jun 29, 20 13:15

Post #3 of 15 (1794 views)

Quote:

Also, how do I know if I need a short cage, medium, large?

Turns out on certain derailleurs (mechanical), the indexing is built into the shifter. I'm going through a similar upgrade on my road bike, and I only need to swap out the rear shifter to make it 11-speed. Might save you some $. You still need a new chain and a cassette though. As Jim mentioned, cassette choice is really up to your fitness level and preferences for climbing/flats. I'm using an 11-32 cassette as I'll be swapping the wheels between my road and tri bikes, but I'm also considering grabbing a 11-25/11-28 for flatter races.

Last edited by: conky2313: Jun 29, 20 13:18

Re: Changing from 10 to 11 spd on tri bike [jimatbeyond] [ In reply to ]

Jun 29, 20 15:34

Post #4 of 15 (1732 views)

jimatbeyond wrote:

"Should I get a different cassette just to have different options? maybe a 12 with 30, 32? or a smaller one, 25 or 27?"

Depends on where you will be riding.

"Also, how do I know if I need a short cage, medium, large?"

A short cage can handle up to 28 teeth.

A medium cage can usually handle up to 34 teeth.

Road rear derailleurs aren't available with a large cage.

You can typically go a few teeth higher than the mfg recommendation (ex. 30T on a short cage). The shifting into the 30T cog (when in the big ring) won't be super-crisp, but it will work (and you aren't really meant to "crosschain" [big ring w/largest cog] anyway).

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Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jun 29, 20 15:47

Post #5 of 15 (1715 views)

I'd just stick with the 11-28. That's plenty of range.

Definitely wouldn't downgrade to a 12t small cog. And a 38/28 gearing is fine for anything down to 7mph. If you're regularly going less than 7mph, then maybe up it to a 32t or 34t. But that would likely require a new rear derailleur

Last edited by: indianacyclist: Jun 29, 20 15:48

Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jun 29, 20 16:17

Post #6 of 15 (1694 views)

Which gear are you using the most, do you find that the steps between gear is too big...

Ex: by going from a 11-25 to an 11-30... you gain 24, 27 and 30 but you loose 16, 23 and 25... (bigger gaps with 10 gears)
https://si.shimano.com/...M-RACS001-01-ENG.pdf

For YOUR riding, which one are you going to miss the most.

Re: Changing from 10 to 11 spd on tri bike [indianacyclist] [ In reply to ]

Jun 29, 20 16:19

Post #7 of 15 (1691 views)

Thanks! yeah, I almost never go under 7mph, so maybe get another cassette with closer range, for flats? 11-25 maybe?

Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jun 29, 20 16:33

Post #8 of 15 (1676 views)

Might as well go as close to a straight block as possible, 11-23

That way you have all sorts of gearing options for 20mph+ racing. Avoid the 2t jumps as much as possible

Re: Changing from 10 to 11 spd on tri bike [indianacyclist] [ In reply to ]

Jun 29, 20 16:56

Post #9 of 15 (1663 views)

Gotcha, thanks!

Re: Changing from 10 to 11 spd on tri bike [jimatbeyond] [ In reply to ]

Jun 29, 20 16:59

Post #10 of 15 (1659 views)

Ok! thanks, yeah, terrain varies, so that is why I considered a "climbing" cassette and a "flats" cassette... or maybe the same in both bikes... as for the cage size, thanks, I did not know they did not come in large lol

Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jun 29, 20 17:38

Post #11 of 15 (1638 views)

If you switch cassettes that are quite a bit different, you will probably need to install a longer or shorter chain.

Re: Changing from 10 to 11 spd on tri bike [jimatbeyond] [ In reply to ]

Jun 29, 20 18:23

Post #12 of 15 (1616 views)

jimatbeyond wrote:

If you switch cassettes that are quite a bit different, you will probably need to install a longer or shorter chain.

Assuming:

1. Both cassettes have 11t as the highest gear; and
2. That you size the chain appropriately for the largest cog on your climbing cassette;
3. You are using the same rear derailleur.

then you should be able to use the same chain for both cassettes.

Re: Changing from 10 to 11 spd on tri bike [mcalista] [ In reply to ]

Jun 30, 20 11:53

Post #13 of 15 (1495 views)

Ohhh I forgot about chain length... ok, that's something to consider too. Thanks!

Last edited by: MarioTB: Jun 30, 20 11:53

Re: Changing from 10 to 11 spd on tri bike [jimatbeyond] [ In reply to ]

Jun 30, 20 11:54

Post #14 of 15 (1493 views)

Right! I did not take that into consideration. Thanks!

Re: Changing from 10 to 11 spd on tri bike [MarioTB] [ In reply to ]

Jul 2, 20 5:12

Post #15 of 15 (1379 views)

Some things I hadn't seen mentioned:

If you are using shimano then you cannot just replace the rear shifter, you will need a derailleur too. The pull ratio is different.

Your cassette body must be able to accept an 11 speed cassette

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