jzsoup

I'm having a hard time figuring this out and need some help. I'm looking at a new bike (handbike actually since I'm a para). The bike I have now is a 1x10 with a 36 tooth chainring and an 11-50 Sunrace cassette. The new bike I'm looking at is also a 36 tooth crank with Alfine 11G hub. How do I figure out how the gearing will compare to my current bike? Clearly I'm not smart enough to find the answer online.

Thanks everybody!

Dean V

The website I saw said it had a 408% range with a 0.527 low to a 2.153 high.
Your 11-50 is a 455% range so you would have to get by with a reduced range of gears.
It would be the same as an 11-45.
So a 36t chainring to a 24t hub sprocket on the Alfine hub would be the same gearing range as a 36 chainring and 11-45 cassette.

jzsoup

So I assume the 455% is calculated as 50/11 = 4.54 * 100 = 455% **********

Am I doing this correctly?

Dean V

Yes.
And the 0.527 low means the hub speed is its input speed x 0.527.
High of 2.153 is a hub speed of input speed x 2.153.
Hub range is (2.153 / 0.527) x 100 = 408%

Gotcha38

The Sheldon Brown gear calculator is great for these kinds of calculations.

https://www.sheldonbrown.com/gear-calc.html

jzsoup

Can you show me the math to get to the 11-45 numbers?
I understand how to get to the 45: 408% / 100 = 4.08 x 11 = 45. The part I'm not understanding is how to calculate the 11. In this calculation I "just assume" the 11 is what it is. How do I do the math to prove the 11 is correct????

I really appreciate your help!

jzsoup

I've spent some time on there but still not getting it figured out. I also wasn't much help on my 4th grader's math home work last year during home school either, so maybe that's the problem.

jfranci3

I had one of these alfines.

A few thoughts -
1) On a bicycle, the weight of the hub (+800gr? over 11sp) was very noticeable when carrying or lifting the bike or adjusting the bike at a light. It actually makes it hard to carry with all the weight in the rear.
2) The cable movement at the hub from gear to gear are very close and unevenly spread. The cable doesn't clamp well enough to prevent slippage. It took a decent amount of work to keep it in adjustment. Basically the hub can't shift until things line up and your hand strength is enough to pull the cable a bit while the hub is waiting for gears to mesh. https://forums.mtbr.com/internal-gea...er-927515.html
3) The steps in the gears were pretty big. If you're used it an 11-50 1x10, it's about the same.
4) You can feel in the inefficiency. It's not all that much worse than a derailleur system (3-4%), but it's noticeable, especially in the higher gears. I wouldn't put this on an athletic bike, but it'd be great for a commuter, fat bike, cruiser, muddy MTBs, maybe a downhill bike,


The cable issue was the biggest problem. I wouldn't do it without the DI2. It'd be worth every penny here. I think you're looking at $20 on the hub and $350 for the Di2 other stuff. Also note that Shimano is coming out with wireless Di2 shifters, which would be HUGE for your handcycle.
Also, the 8sp (11-36 cassette) is supposed to be more reliable than the 11 (11-46), if you can do without the top 2 gears, that's $200 saved.

Dean V

I just multiplied the 11 by 4.08 and rounded off the answer to 45.
If you did go with this hub you would have to decide on which end of the gearing range you could compromise.
ie. would you miss the 11t top or the 50t low the most?
If you really don't want less range but want an internal geared hub I guess you could look at Rohloff which is 14 speed and 526% range. That would be a jump in price though.

jzsoup

But how did you know that it was 11? Is that just an assumption?

Dean V

I am just saying the range is equivalent to an 11-45 cassette to give you a point of reference against what you are used to (11-50).
Could say 12-49 or 15-61. Whatever, its all the same.
I can't say what the actual gearing is on the bike you are looking at as you never said what size sprocket is on the hub?
But it doesn't really matter as chainrings and sprockets can be changed to move all the gears either up or down but the range of 4.08 is fixed by the internal hub.