Re: Changing from 1st to 12th
Posted: 28 Jan 2019, 8:22pm
With down-tube shifters, you could move both levers with one hand
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AndyK wrote:ndwgolf 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 would be interested to find out some more about that?
Neil
Shimano's Di2 offers this ("Synchronized Shift" mode). You can even customise its shifting choices if you want. I can't say I've tried it.
ndwgolf wrote:Something got me thinking today so I will ask the crowd. When going up hill while changing gears from say 8 to 1 but once you get to 1 you now need to drop the front ring to the smaller ring........ how do you go about that because you will then be going to the very easiest gear instead of the next gear if you know what I mean??
Neil.
Brucey wrote:AndyK wrote:ndwgolf wrote:I would be interested to find out some more about that?
Neil
Shimano's Di2 offers this ("Synchronized Shift" mode). You can even customise its shifting choices if you want. I can't say I've tried it.
one comment from those who have tried it is that the combined (double) shift takes about x3 as long as a normal rear shift and you may not necessarily know it is coming. It is still a good idea to back off during the shift, so if you don't keep track of things you may find yourself pausing for long enough for a rear shift but not a double shift. I confess this would drive me absolutely crackers.
cheers
ndwgolf wrote:Something got me thinking today so I will ask the crowd. When going up hill while changing gears from say 8 to 1 but once you get to 1 you now need to drop the front ring to the smaller ring........ how do you go about that because you will then be going to the very easiest gear instead of the next gear if you know what I mean??
.
Brucey wrote:IIRC the standard gear ratios on your bike use a 50,34 chainset and a shimano 11s 11-28 cassette. You can see these ratios depicted here
http://ritzelrechner.de/?GR=DERS&KB=34,50&RZ=11,12,13,14,15,17,19,21,23,25,28&UF=2135&TF=90&SL=2.4&UN=MPH&DV=teeth
the greyed out ratios use a chain angle more than 2.4 degrees so are to be avoided, but you can set this control to different values if you want.
drossall wrote:I think about it as the front gear giving ranges. They necessarily overlap. If I know I'm hitting a hard hill and I'm going to want the low range, I may as well get there as soon as possible. In general, the thing to avoid is difficult changes when you're already struggling - partly because it's just harder, and partly because you'll have the gears under load in your effort to get up the hill, and gears change better if you can slacken off the pressure just slightly as they change.
Cugel wrote:drossall wrote:I think about it as the front gear giving ranges. They necessarily overlap. If I know I'm hitting a hard hill and I'm going to want the low range, I may as well get there as soon as possible. In general, the thing to avoid is difficult changes when you're already struggling - partly because it's just harder, and partly because you'll have the gears under load in your effort to get up the hill, and gears change better if you can slacken off the pressure just slightly as they change.
This is the best approach. I think of the chain rings as providers of two or three sets of overlapping ratios: low; medium;high. One selects the range in anticipation of the coming terrain, not when halfway through the terrain - where this is possible.
thelawnet wrote:….The various 1x setups generally require chain angle tolerances of 2.6°, e.g., S-Works Diverge (40x11-40), SRAM 44x10-42, SRAM 32x10-50, Shimano XTR 10-51, etc.
So while the big/big and small/small are quite definitely to be avoided, using the second-biggest and the second-smallest is not such an issue considering that a lot of bikes are being sold with unavoidable bigger chain angles.....
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
Brucey wrote:thelawnet wrote:….The various 1x setups generally require chain angle tolerances of 2.6°, e.g., S-Works Diverge (40x11-40), SRAM 44x10-42, SRAM 32x10-50, Shimano XTR 10-51, etc.
So while the big/big and small/small are quite definitely to be avoided, using the second-biggest and the second-smallest is not such an issue considering that a lot of bikes are being sold with unavoidable bigger chain angles.....
I did mention that you can arbitratily set your limits to chainline anyhow you like. Also please note that just because some folk are daft enough to make bikes that require extreme chain angles and other folk are daft enough to buy them still doesn't make it a good idea; it is a much worse mechanical abomination than normal.