This question arose in the Thread: "Diamond Frame Agattu - The Photo.
That was not the right thread to post this topic: but somewhere on this Forum is quite a tract of posts on this subject.
essexman
Junior Member Join Date: Dec 2007
Posts: 19
________________________________________
Hi Just some feedback on gearing.
I had planned to mod mine, but actually i dont think i will. I live in area with a lot of steep hills\slopes and i plan to move a lot of weight and\or avoid sweating up them, so i think i'll keep my gears as is for the minute.
I'll see how i feel after a hot summer (fingers crossed).
I'm a skinny spinner, so i dont like heavy gearing generally.
From Mandy
Hi Essexman
You haven't explained your gearing problems that I can see?
Please elaborate and one of the Guru's will get back to you, namely Flecc hopefully?
Kindest Regards
Mandy
I see the question of gearing (rider’s) on electric bikes has been raised again.
This topic was the subject of a long discussion on this Forum back in late 2006 and early 2007. I put in a lot of effort to understand, redesign and change the gearing on my bike: I won’t mention its name because that is irrelevant. The conclusions I reached in theory were the one’s that I applied in practice. Although they were not a perfect solution to my needs because the bike had its own characteristics, they were a vast improvement to my enjoyment of my bike. Funny though, the gearing came into its own when I was least enjoying the bike. I never had the good fortune to ‘sail’ up moderately steep hills (like 10%) without a care in the world, legs akimbo!
I started from the premise that riders in the Tour de France knew something about cycling and because it was the sadism of T de F organizers to put a few mountains into the route, gearing would be given a high priority in the bicycles’ set up. To a man they used a bottom gear of 39 inches. It was this ‘size’ that I felt must be ideal because of the limitations of my bike (and those of most other e-bikes).
Happily the Shimano Nexus 7 (or 8) has the right ratios for assisted hill climbing on the one hand and ‘barreling’ down hills on the other (though why anyone would want to pedal down hill is beyond my comprehension – but it’s a free world. BUT you won’t get caught up in a T de F sprint finish, so you won’t need a top gear of 120 inches and the occasions you are caught out on the Fens with a tail wind blowing at 80 knots are once in a lifetime.
With Shimano Nexus the die is cast in comparative ratios: the only variable is the rear sprocket. One can change the chain wheel size but this is getting more complicated and unnecessary. You only have to work out what your optimum cadence is for cycling under ‘neutral’ conditions (flat & wind free) to fetch up the middle gear (presumably you are thinking of traveling at 15 mph). Then you have 3 options for going faster (same cadence) and 3 options for when the going is harder. You may decide that to accommodate the changes in upward gradients, 4 ratios fit the bill, so you will be left with 2 for faster.
There is a wonderful website which deals with all (more or less) variables in bicycles wheel size, rear sprocket/chainwheel ratios for derailleur gears and the mix and match of hub gears in terms of cadence/miles per hour:
http://www.sheldonbrown.com/gears/
and another : http://www.arachnoid.com/bike/index.html derailleur gears only.
Sheldon Brown’s tables are set up to show speed/given cadence/gear ratio inches/ratio %age increase for all known hub gears – it needs to be worked at to get the best understanding of it.
Personally I opted for a bottom gear of 39 inches and a top of 85 inches.
I had already hit upon the notion that a really low bottom gear (39 inches) would be useful for getting home in the event of a power failure (battery or motor).
Peter
That was not the right thread to post this topic: but somewhere on this Forum is quite a tract of posts on this subject.
essexman
Junior Member Join Date: Dec 2007
Posts: 19
________________________________________
Hi Just some feedback on gearing.
I had planned to mod mine, but actually i dont think i will. I live in area with a lot of steep hills\slopes and i plan to move a lot of weight and\or avoid sweating up them, so i think i'll keep my gears as is for the minute.
I'll see how i feel after a hot summer (fingers crossed).
I'm a skinny spinner, so i dont like heavy gearing generally.
From Mandy
Hi Essexman
You haven't explained your gearing problems that I can see?
Please elaborate and one of the Guru's will get back to you, namely Flecc hopefully?
Kindest Regards
Mandy
I see the question of gearing (rider’s) on electric bikes has been raised again.
This topic was the subject of a long discussion on this Forum back in late 2006 and early 2007. I put in a lot of effort to understand, redesign and change the gearing on my bike: I won’t mention its name because that is irrelevant. The conclusions I reached in theory were the one’s that I applied in practice. Although they were not a perfect solution to my needs because the bike had its own characteristics, they were a vast improvement to my enjoyment of my bike. Funny though, the gearing came into its own when I was least enjoying the bike. I never had the good fortune to ‘sail’ up moderately steep hills (like 10%) without a care in the world, legs akimbo!
I started from the premise that riders in the Tour de France knew something about cycling and because it was the sadism of T de F organizers to put a few mountains into the route, gearing would be given a high priority in the bicycles’ set up. To a man they used a bottom gear of 39 inches. It was this ‘size’ that I felt must be ideal because of the limitations of my bike (and those of most other e-bikes).
Happily the Shimano Nexus 7 (or 8) has the right ratios for assisted hill climbing on the one hand and ‘barreling’ down hills on the other (though why anyone would want to pedal down hill is beyond my comprehension – but it’s a free world. BUT you won’t get caught up in a T de F sprint finish, so you won’t need a top gear of 120 inches and the occasions you are caught out on the Fens with a tail wind blowing at 80 knots are once in a lifetime.
With Shimano Nexus the die is cast in comparative ratios: the only variable is the rear sprocket. One can change the chain wheel size but this is getting more complicated and unnecessary. You only have to work out what your optimum cadence is for cycling under ‘neutral’ conditions (flat & wind free) to fetch up the middle gear (presumably you are thinking of traveling at 15 mph). Then you have 3 options for going faster (same cadence) and 3 options for when the going is harder. You may decide that to accommodate the changes in upward gradients, 4 ratios fit the bill, so you will be left with 2 for faster.
There is a wonderful website which deals with all (more or less) variables in bicycles wheel size, rear sprocket/chainwheel ratios for derailleur gears and the mix and match of hub gears in terms of cadence/miles per hour:
http://www.sheldonbrown.com/gears/
and another : http://www.arachnoid.com/bike/index.html derailleur gears only.
Sheldon Brown’s tables are set up to show speed/given cadence/gear ratio inches/ratio %age increase for all known hub gears – it needs to be worked at to get the best understanding of it.
Personally I opted for a bottom gear of 39 inches and a top of 85 inches.
I had already hit upon the notion that a really low bottom gear (39 inches) would be useful for getting home in the event of a power failure (battery or motor).
Peter
