Originally Posted by
cny-bikeman
The answer on largest range will vary due to type of chainrings, spacing between the two, derailleur, and chain,
Perhaps I should have stated that, but I am assuming that one cannot just throw really different rings onto an existing groupset and expect things to work well. And, I am aware that there are explicit limits on the sizes of rings available for a given crankset. I'm wondering what is possible,
with the right choice of components and what manufacturers and product lines are good for unusual setups.
Somewhere or another... Ahh,
here... Sheldon Brown references a TA
Cyclotouriste crankset with a huge gap between ring sizes. According to
this, the official name of these are the
Pro Vis 5 and they are possibly no longer manufactured. It also seems to
require old, no longer manufactured derailers. Is this a totally unique product line as far as range between rings goes? If not, what else is there? Anything similar that can be bought without scavenging e-bay or garage sales?
Originally Posted by
cny-bikeman
but I believe 48/28 is impractical due to the steep, low angle climb and drop. The derailleur pushes the chain sideways, not up, and the chainwheels are designed with certain assumptions. The derailleur will not in my opinion be able to push the chain that high, and in the other direction the chain will likely travel right past the small chainwheel due to the steep drop.
I'm assuming that commonplace, new Shimano, Campy, SRAM, etc. derailers will work best with chainrings that are of nearly similar size to what they sell as a complete groupset. However, I'm assuming that what manufacturers list as min/max ring sizes are limits on what they think shifts well, not real limits on what works with friction shifting. Anyone done any actual testing to find out what the real limits are for common front derailers?
Also, while the FD will be far more important in this regard, what difference does the chain and the RD and cassette make?
Originally Posted by
cny-bikeman
As to the smallest difference there is also not a single answer. With today's 11 and 12 tooth small cogs I don't think 53 is very useful, let alone paired with a 48. How often do you expect to be going 40+ mph when coasting is not the better alternative?
Seems quite ridiculous to me as well. But my knowledge and experience is very limited and assuming that something is useless is rather silly unless one has a truly encyclopedic knowledge of the subject. I'm not expecting any really wide differences or any really narrow differences to be "practical" or useful for most people. I'm trying to get an idea of the workable extremes and what uses they might have for a select few.
Again, this is not an "I want this on my bike" post, rather I'm hoping to learn from those with unusual experience and knowledge
just for the sake of learning. Hope that makes sense.