Cassette ratios

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Cassette ratios

Postby xmpt » Fri May 10, 2013 9:44 pm

Hi,

I hope this is in the correct section as I am new to BNA but does anyone know if the ultegra 12-30 cassette will work with an ultegra Di2 rear derailleur? The reason I am asking is I need some extra gear assistance since a cycling accident where I ruptured all the ligaments in my knee.

ta
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by BNA » Sat May 11, 2013 7:07 am

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Re: Cassette ratios

Postby Jesmol » Sat May 11, 2013 7:07 am

From what I could see the di2 rd is still only designed for a max 28t cassette
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Re: Cassette ratios

Postby ozzymac » Sat May 11, 2013 7:51 am

Hi,
I am in the process of doing the same thing, and going by what I have read the 12/30 works fine with di2.

Thats what I am ordering with the new chain so it better work.


Cheers

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Re: Cassette ratios

Postby Jesmol » Sat May 11, 2013 2:15 pm

I'd check first with the shimano documents, Wiggles desc states 28t , and the di2 came out before the 6700a rd which is 30t capable
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Re: Cassette ratios

Postby xmpt » Sun May 12, 2013 4:50 pm

ozzymac wrote:Hi,
I am in the process of doing the same thing, and going by what I have read the 12/30 works fine with di2.

Thats what I am ordering with the new chain so it better work.


Cheers

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thanks for that. I hope it works for you. Please let me know either way.

ta Carl
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Re: Cassette ratios

Postby ozzymac » Sun May 12, 2013 7:10 pm

Jesmol wrote:I'd check first with the shimano documents, Wiggles desc states 28t , and the di2 came out before the 6700a rd which is 30t capable

Hi,
I was going by some reviews of people who have bought the 30 cassette via wiggle. They reckon it works fine with di2.


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Re: Cassette ratios

Postby Crawf » Mon May 13, 2013 9:25 am

30t with Di2 works absolutely fine.
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Re: Cassette ratios

Postby Jesmol » Mon May 13, 2013 10:28 am

Shimano also state a max rear sprocket of 28T, just be aware that you're operating outside their design parameters, therefore expect no warranty if something goes pear shaped.

Also Chain wrap may be a problem, Running compact (50-34 with a 12-30 cassette) gives you a total chain wrap of 34T, capacity of the 6770 RD is 33T
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Re: Cassette ratios

Postby xmpt » Mon May 13, 2013 10:14 pm

Jesmol wrote:Shimano also state a max rear sprocket of 28T, just be aware that you're operating outside their design parameters, therefore expect no warranty if something goes pear shaped.

Also Chain wrap may be a problem, Running compact (50-34 with a 12-30 cassette) gives you a total chain wrap of 34T, capacity of the 6770 RD is 33T


At the moment I have the 54-39 front. The reason I am looking at rear ratios is so I dont have to change the front.

My problem is I tore my PCL (full), ACL (50%), multiple tares to the meniscus and cracked the ACL mounting horn all due to a pedestrian steeping in front of me at 52km/h in Jan this year. Anyway what this means is as soon as I hit a hill and start to load the knee I end up in lots of pain and with a very swollen knee.

Really grateful for all of the advice
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Re: Cassette ratios

Postby Jesmol » Tue May 14, 2013 9:24 am

My honest opinion is that you will be much better off going to compacts, or steering clear of hills until your knee clears up. Good luck with whatever you do, sounds like a nasty injury.
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Re: Cassette ratios

Postby theprophet » Thu May 16, 2013 6:37 pm

It works but shimano say a 28t is the largest we should go. We do it regularly at our shop for some of our mates bikes
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Re: Cassette ratios

Postby Crawf » Fri May 17, 2013 8:38 am

It ain't 'Pro' to have a 30t on the back but I loved it and don't really give a fluff, it allowed me to stay on the big ring (53/39) for almost any terrain and maintain a good rhythm besides obviously Mt Coottha etc.
Less faffing about switching the front and the fact that Di2 laps up cross-chaining without issue is a win-win for me. Never had one issue and no signs of premature wear or strain on the drivetrain.
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Re: Cassette ratios

Postby optiumcarbon » Fri May 17, 2013 5:15 pm

As stated before, Di2 is designed to have a max size of 28t rear cassette but a 30 will fit and work fine.
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Re: Cassette ratios

Postby Xplora » Fri May 17, 2013 5:38 pm

Sounds like the mechanical Ultegra 2012 should be able to handle 12-30 then? I've been feeling a bit defeated since biting off more Bowen Mountain than I could chew, and I've still got the 12-30 that came with the Beater.
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Re: Cassette ratios

Postby MREJ » Fri May 17, 2013 6:28 pm

My wife has Ui2 50/34 with a 30 at the back. She loves it. It runs fine on the small ring, but the shop cautioned against using the 50/30 combo.

I tried it once on the work stand and it stretched the chain out and jammed. A nervous moment there.

I did ask the shop why we couldn't just run a longer chain; there was a reason, but I don't remember it.
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Re: Cassette ratios

Postby im_no_pro » Sat May 18, 2013 12:50 am

MREJ wrote:
I did ask the shop why we couldn't just run a longer chain; there was a reason, but I don't remember it.


Most likely too much slack for the derailleur to handle at the other end of the spectrum.
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Re: Cassette ratios

Postby RonK » Sat May 18, 2013 4:51 pm

im_no_pro wrote:
MREJ wrote:
I did ask the shop why we couldn't just run a longer chain; there was a reason, but I don't remember it.


Most likely too much slack for the derailleur to handle at the other end of the spectrum.

Yes, the chain may well rub on the derailleur when on small-small.
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Re: Cassette ratios

Postby GasCyclist » Mon May 27, 2013 12:45 pm

I have a different question regarding this. If I purchase the new Ultegra 6700A derailleur is it possible to swap from 12-25 to 12-30 without any dramas.

What I mean is, one wheel has a 12-25 for normal bunch rides and another wheel has the 12-30 for when I decide to go on a nice climbing ride. I currently ride a standard crank.

Cheers
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Re: Cassette ratios

Postby Jesmol » Mon May 27, 2013 3:09 pm

GasCyclist wrote:I have a different question regarding this. If I purchase the new Ultegra 6700A derailleur is it possible to swap from 12-25 to 12-30 without any dramas.

What I mean is, one wheel has a 12-25 for normal bunch rides and another wheel has the 12-30 for when I decide to go on a nice climbing ride. I currently ride a standard crank.

Cheers

The only issue I have when swapping wheels is slight variances in the hub / cassette positioning can get the shifter indexing slightly out of whack.
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Re: Cassette ratios

Postby toolonglegs » Mon May 27, 2013 3:38 pm

OP mentions a 30 cassette in Ultegra... where do I find one?.
Last year I ran 9 speed 11/34 on my CX bike with a 38/46 and a XTR rear mech which worked well. But I want a 10 speed set up for my non mud bike, want to try running a 12/30 on a 34/50 crank... think I might get a medium cage derailleur though?.
Main reason is lots of climbing coming up over the next 6 weeks... but most of it will be at the tail end of tours looking after people... which means 4kmph for long periods sometimes...would like to look after my knees!. But this year I won't be offering to push people the entire way up Grand Cols!.
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Re: Cassette ratios

Postby GasCyclist » Mon May 27, 2013 3:41 pm

The only issue I have when swapping wheels is slight variances in the hub / cassette positioning can get the shifter indexing slightly out of whack.


Is this swapping between the 12-25 and 12-30?
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Re: Cassette ratios

Postby Jesmol » Mon May 27, 2013 4:11 pm

GasCyclist wrote:
The only issue I have when swapping wheels is slight variances in the hub / cassette positioning can get the shifter indexing slightly out of whack.


Is this swapping between the 12-25 and 12-30?

12-27 (in the training wheel) and 11-28 on the road wheel. In the end I got sick of having to tweak the shifting everytime I swapped wheels, and just train on my road tyres now.
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Re: Cassette ratios

Postby toolonglegs » Mon May 27, 2013 4:16 pm

GasCyclist wrote:
The only issue I have when swapping wheels is slight variances in the hub / cassette positioning can get the shifter indexing slightly out of whack.


Is this swapping between the 12-25 and 12-30?


If you are using two different types of wheels with the cassettes fitted it could mean you need to adjust the high/lows on the derailleur each time you change... the same can be said for different types of cassettes. A 105 cassette can sit slightly different to an Ultegra one meaning an adjustment each time. But sometimes nothing needs adjusting.
Also if doing this you may want to be on reasonably new chain and cassettes. As an old chain will slip on a new cassette. Ideal would be a matched pair, ie swapping chain and cassette as a pair... especially if you run one cassette much more often than the other.
The last thing would be chain tension... check your chain is long enough for the 30 tooth etc.
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Re: Cassette ratios

Postby GasCyclist » Mon May 27, 2013 4:38 pm

High Low as in the Barrel Adjuster?
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Re: Cassette ratios

Postby Jesmol » Mon May 27, 2013 4:53 pm

GasCyclist wrote:High Low as in the Barrel Adjuster?

Worst case may need the derailleur stop adjusting screws.
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