Changing from 1st to 12th

General cycling advice ( NOT technical ! )
thelawnet
Posts: 1654
Joined: 27 Aug 2010, 12:56am

Re: Changing from 1st to 12th

Postby thelawnet » 29 Jan 2019, 1:35pm

ndwgolf wrote:Okay update. I have now figured out how to set up my Di2 shifters so that when I go from large to small ring and vise versa it will automatically drop or add 3 cassette gears. Tomorrow I’m out riding so I will give it a go and give you some feedback when I get home.
Neil


This is called 'semi-synchro'. My guess is you probably want it to drop/add only 2 cogs, as 3 cogs will typically mean you haven't changed anything, effectively.

It would be worth trying the full synchro mode as well, for comparison.

ndwgolf
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Joined: 2 Sep 2018, 2:50am

Re: Changing from 1st to 12th

Postby ndwgolf » 29 Jan 2019, 1:55pm

thelawnet wrote:
ndwgolf wrote:Okay update. I have now figured out how to set up my Di2 shifters so that when I go from large to small ring and vise versa it will automatically drop or add 3 cassette gears. Tomorrow I’m out riding so I will give it a go and give you some feedback when I get home.
Neil


This is called 'semi-synchro'. My guess is you probably want it to drop/add only 2 cogs, as 3 cogs will typically mean you haven't changed anything, effectively.

It would be worth trying the full synchro mode as well, for comparison.

This is what I have set up.
ImageImageImage
Looking forward to trying it tomorrow.
Neil


I'm a trendy consumer. Just look at my stupid phone.

Brucey
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Re: Changing from 1st to 12th

Postby Brucey » 29 Jan 2019, 2:02pm

re; cross-chaining is a bit worse than you might expect. BITD it was (as a rule of thumb) with a 5/6s system convenient to assume that chainrings were spaced about the same as sprockets, at least for chainline purposes. But with 10/11s systems the chainrings are still spaced ~8mm apart which is closer to two sprocket's worth.

This means that the big ring could be centred over sprocket #7 of an 11s cassette. In practice with a 130mm back end I think (IIRC its been a while since I did the sums/measurements but I think sprocket #7 is about 46mm chainline) the big ring is centred between #7 and #8. This means that the cross-chaining running big-big is actually worse than predicted in the gear calculator (which I think assumes that the chainset is centred over the cassette). The cross-chaining in top gear is about the same as running in sprocket 3, not sprocket #2

Overall this diminishes the utility of the bike, especially for the typical rider; it still ain't a good idea to run small-small, which leaves you with a load of gears in the 50-70" range in which you are either forced to use small inefficient chainwheels/sprockets or have a worse chainline than you would like. Since these are the kinds of gears which you would use on false flat etc quite small changes in efficiency can make a bigger difference than normal.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

thelawnet
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Joined: 27 Aug 2010, 12:56am

Re: Changing from 1st to 12th

Postby thelawnet » 29 Jan 2019, 2:26pm

ndwgolf wrote:Image


I think the idea here is that you can potentially setup two different shifting patterns (by adding different maps), when using full synchro. This is something you could change according to whether you wanted to stay longer in the big ring or change down more quickly.

At the moment it's setup to use the 10 smallest gears in the big ring, then change down the front and two up at the back.

In the small ring it will use the 9 biggest cogs before changing up and down two.

Potentially you could set it to change down to the 23 tooth after the 27 tooth cog, so not use the 30 & 34 cogs at the front.

The 36/19 to 52/23 seems quite reasonable.

mattsccm
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Re: Changing from 1st to 12th

Postby mattsccm » 29 Jan 2019, 5:32pm

Just for interests sake find an online gear calculator , Sheldon Brown has one, and look at your ratios. It might give you an interesting look at where the gear ratios are and what changes you might make.

drossall
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Joined: 5 Jan 2007, 10:01pm
Location: North Hertfordshire

Re: Changing from 1st to 12th

Postby drossall » 29 Jan 2019, 9:58pm

ndwgolf wrote:Okay update. I have now figured out how to set up my Di2 shifters so that when I go from large to small ring and vise versa it will automatically drop or add 3 cassette gears. Tomorrow I’m out riding so I will give it a go and give you some feedback when I get home.
Neil

Blimey, that sounds complicated. With my gears, I just do what Nigel says and think a hundred yards ahead. You're making the decision the night before :?: :shock: :lol:

ndwgolf
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Joined: 2 Sep 2018, 2:50am

Re: Changing from 1st to 12th

Postby ndwgolf » 29 Jan 2019, 10:59pm

drossall wrote:
ndwgolf wrote:Okay update. I have now figured out how to set up my Di2 shifters so that when I go from large to small ring and vise versa it will automatically drop or add 3 cassette gears. Tomorrow I’m out riding so I will give it a go and give you some feedback when I get home.
Neil

Blimey, that sounds complicated. With my gears, I just do what Nigel says and think a hundred yards ahead. You're making the decision the night before :?: :shock: :lol:

That sounds a bit like when computers first came out..........."That won't catch on and the likes"

The Di2 is new technology that has software that potentially can assist you in smother gear changes. I will be trying it in the next few hours, hopefully I will really like, maybe it will be something that will take time to get used to, or maybe I will just hate it......either way I am going to try it and see what its like.
At the end of the day I am a 61 year old fat guy that gets great pleasure out of riding my bike for fun, I'm also a gadget kind of guy so Di2 is right up my street :D :D :D

Neil

drossall
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Location: North Hertfordshire

Re: Changing from 1st to 12th

Postby drossall » 30 Jan 2019, 7:54am

Oh enjoy :D

And if we should meet and you show it to me, I'll be genuinely interested and I'd love to have a go. I just saw the funny side :lol:

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Cugel
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Re: Changing from 1st to 12th

Postby Cugel » 30 Jan 2019, 8:33am

drossall wrote:Oh enjoy :D

And if we should meet and you show it to me, I'll be genuinely interested and I'd love to have a go. I just saw the funny side :lol:


There is, though, an argument that a better understanding and direct control of a tool (a bike for getting the pleasures of cycling, in this case) can greatly increase the pleasures found in using it. I think this is true of learning in a direct fashion, via an understanding of the control modes, for bicycle gearing.

It's certainly true in many crafts. I learnt all about the advantages to be gained from hand tool woodworking over machine-only woodworking via many hundreds of hours of errors and corrections. The hand tool use gives a great insight into how wood is best cut, planes, shaped, glued and otherwise turned into furniture. I believe the same approach works for cycling.

This is not to dismiss stuff like electronic gears or any other automated mechanism of cycling. But if you understand the base operations and principles intimately, from having to arrange and operate them yourself, this still allows improvements to cycling such as knowing how to best select a gear ratio and when .... even if you eventually do so with an electronic thing and a button. I use machine tools as well as hand tools in woodworking but understand much better how to employ the machine because of what I understand it to be doing at it's interface with the wood, from my learning with the intimacy of the hand tool to wood interface.

Cugel

ndwgolf
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Joined: 2 Sep 2018, 2:50am

Re: Changing from 1st to 12th

Postby ndwgolf » 30 Jan 2019, 8:40am

Update;
Just finished a 60+ kilometers ride and the synchronized gear changing was amazing especially going from small to big ring. Going from big to small ring needs just a milly second longer off the power to get a really smooth quite gear change......... I’ve hardly been in the small ring as most of the time I’ve just powered the big ring, but since trying this synchronization gear changing I can see myself using the small ring more often....... “like the Pros do” :D :D :D

Airsporter1st
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Re: Changing from 1st to 12th

Postby Airsporter1st » 30 Jan 2019, 9:09am

Airsporter1st wrote:Presumably, the electronic shifters are/could be programmed to take care of this, shifting both front and rears practically simultaneously. If not, why not?


I think this is the first suggestion I've made that anyone has actually taken any notice of. Usually my meagre contributions are eclipsed by pronouncements from far more learned members.

Glad you've got it set up and you're now realising the full potential of these 'new fangled devices', which so many seem to disparage.

ndwgolf
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Joined: 2 Sep 2018, 2:50am

Re: Changing from 1st to 12th

Postby ndwgolf » 30 Jan 2019, 9:43am

Airsporter1st wrote:
Airsporter1st wrote:Presumably, the electronic shifters are/could be programmed to take care of this, shifting both front and rears practically simultaneously. If not, why not?


I think this is the first suggestion I've made that anyone has actually taken any notice of. Usually my meagre contributions are eclipsed by pronouncements from far more learned members.

Glad you've got it set up and you're now realising the full potential of these 'new fangled devices', which so many seem to disparage.
if there really is a “best thing since sliced bread”. This is it :D
Now if only I can figure out how to program one of the horny buttons to go from sync 1 to 2 to manual I’ll be a happy camper.
Neil

Brucey
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Re: Changing from 1st to 12th

Postby Brucey » 30 Jan 2019, 4:12pm

I'm glad it works for you and that you like it.

Needless to say you can achieve a very similar result using manual shifters, which is what folk have been doing for the previous hundred years or so; it just takes a bit of practice, a skill to be learned if you like. Possibly you could have learned how to shift like that in about the same length of time it took to dig into the software..... :wink: However in use, Di2 is almost certainly faster, which might make a difference in the heat of competition.

TBH I'm not sure how the pros usually have their Di2 (or similar) set up. I suspect that many of them have it set to allow full manual control; I have seen pro riders choosing to use big-big briefly rather than risk the chain unshipping at the front.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

drossall
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Re: Changing from 1st to 12th

Postby drossall » 30 Jan 2019, 9:27pm

Can you program it to make the hills less steep? :D

Jamesh
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Joined: 2 Jan 2017, 5:56pm

Re: Changing from 1st to 12th

Postby Jamesh » 31 Jan 2019, 6:24pm

:idea: Does di2 work best with sis or friction down tube levers?!!!!

Surely you still select the gears?

Otherwise you could have comfort sport and track settings lol!

I'm sure it will come down to have an up and down button and you press as required and it choose when to change big ring?

Or perhaps they do already. I'll look it up in the yellow pages :roll: :roll: