FreeFloat

New here and tried search, but can't find an answer.
I understand that the Alfine 11 internal hub can provide a 409% gear range.
What is the highest range attainable from a rear derailer when using only one chain ring?

jsdavis

Biggest range is 11-34 or 12-36; something like that anyways.

ThermionicScott 

Shimano makes an 11-36 10-speed cassette for mountain bikes. That's a 327% range if my math is correct, and it's hard to imagine needing anything more with the right chainring.

Thor29

Your math is correct - I get the same number.

prathmann

There's also the Capreo cassette that has a normal range of 9 to 26 teeth. That's not that wide, but the larger cogs on the cassette are interchangeable with those from other Shimano cassettes so one could modify it for a wider range. Here's someone who modified it in the other direction to get a narrower range with closer spacing:
https://rob.ragfield.com/2010/07/capr...ification.html

But taking the larger cogs from the 11-36 MTB cassette and putting them on the Capreo with its smaller cogs would give you a cassette with 9 to 36 or a 400% range.

fietsbob

put that 11-36cassette on a dual drive 3 speed IG hub/cassette combo..
and there are 2 speed planetary gear cranks that still have only 1 chainring..

bud16415

On my tour bike I have 12-36 cassette against a middle ring that’s 42t that gives me a gear inch range between 31 and 94. That could easily cover most people’s needs.

Retro Grouch 

What's the point?

Lowest gear is practically limited by how slowly you can pedal and still keep the bike vertical. Highest practical gear is limited by your power to frontal area ratio. It's not too difficult to find hardware to suit those criteria.

bud16415

I don’t know what the point is. I guess he was asking if a RD single front could get close to an IGH in terms of range. In my case I have went as low as 16 GI and still kept the bike upright but I thought it would be less work to push at that point. 18 or 20 GI will let almost anyone climb anything. As far as top end gears I don’t think as most do that the limit is strength and frontal area. I enjoy my tall gears when I’m getting a little help from gravity or the wind and I don’t feel like spinning. Anything much over 100 GI trying to spin it up and build lots of watts is going to be tough for most. But I don’t go full out spin or mashing when I’m in them. Sometimes a slow cadence in a high gear works ok for me. I couldn’t get the full range I would like from a single chain ring where I live and ride. If I was in FLa. I could easily get by with a single in front.

FreeFloat

I'm used to riding a heavy steel mountain bike w/ racks carrying a load mostly on paved roads with some stretches of sandy gravel in an area with hills. On any given ride I end up using the small ring and largest cog as well as the big ring w/smallest cog. I'm 60 and my knees are getting old, so I fight the urge to stand for climbing.
For various reasons I want to put together a bike with only one chain ring, and was advised to go with the IGH for that purpose. I never really checked out the maximum range a rear derailer could get, but once I saw the price on Alfine 11 bikes or components I figured I better find out!
Thanks, I now have some numbers and thoughts to consider before taking the plunge.

bud16415

Here is the best gear calculator I have seen. I use it a lot to do comparing between bikes I have and I can relate what each gear I know about feels like and then use that to design a better gear system to suit my needs.
https://home.earthlink.net/~mike.sherman/shift.html

If you can tell us what you have now that might help with some suggestions.
I run a triple but have changed a lot of things for reasons similar to what you say are your reasons. Price was a concern here also. Sounds like you can do ok on your bike but are not keen about doing the front shifts. I also didn’t like front shifting and many of the mtn triples had me with half my gears on one ring and half on the other. That’s why I took a look at changing things so I stay on the middle ring most of the time with a wide spaced cassette.

ThermionicScott 

Why wouldn't you want to stand for climbing? Your knees are straighter, and you're using more of your body weight to move the pedals. I think sitting and mashing an almost-low-enough gear would be worse.

FreeFloat

Absolutely, and that's why I want a TRULY low enough gear!
I'm going to go count some teeth on a few of my bikes and then crunch them into that calculator linked to above.

FreeFloat

Thanks!. I'll plug in some numbers a bit later.

fietsbob

consider a Recumbent Tadpole tricycle , you can gear those really low,
and not fall over, on hills.

the aforementioned dual drive and a triple crank will get that done..


FWIW Rohloff is 526%..

Schlumpf Speed Drive multiples everything by 1.6X in high range

(still just 2 chainwheels)

FreeFloat

Didn't want to get into too much detail for simplification purposes but maybe you guys CAN give me some usable input so............
Advanced osteoarthritis in my neck forced me out of my tandem, road bike, and mountain bike early this year and into the more upright frame geometries of my kid's 26" small frame mountain bikes which I converted w/ taller stems and ape-hangers during recovery from the acute stages of my flare-up.
Able to ride on regularly again now, I would like to purchase/build a nicer higher performance upright rider for myself. Hey, one of the ring sets I just got done counting that I rode two days ago not only was pre-hyper-drive, but Bio Pace! No wonder my knees are shot!
So why not recumbent? Delta? Tadpole? Crank-forward?
Because long before my neck crapped out on me my feet did.
With zero cartilage left in several of the major joints in my feet I've only been able to cycle or run true barefoot. Not "barefoot" technology shoes, but skin to the pedal/ground barefoot for walking, cycling, running problem free. True FreeFloat not just at the "connection" to the pedal, but free float in every single foot joint
I have learned to accept the additional crash risks inherent in the activity, so I ride much more cautiously as a result.
That's the reason I won't:
Stand on the hills (one slip and.....)
Ride a crank-forward/recumbant/especially tadpole (one slip and.......)
For that same reason (reduced risk to feet) I want to eliminate the usually non-chain covered large ring.
A two ring crank with the larger the "normal" one and the smaller a granny when needed would work most of the time, but since I'm looking at my old man dream barefoot safe ride why not a belt drive 11 speed?
Cause all this aging has slowed down my income as well and I hate to spend $2600 on such a bike when my wife who's only three years younger is riding centuries and looking at a brand new carbon road bike this week!

FreeFloat

But is there a derailler with a long enough cage to handle it from high to low?

fietsbob

Long cage MTB RD will clear the big cog, small one is no issue..
just that 9t means chain contacting half, so. only 4.5t are taking the wear..
at any one time ..

Paul Barnard

Yes, long cage MTB derailleurs.

FreeFloat

Thanks guys,
I'll do some calculations and figure out if that would do the trick. Should be much lighter and cheaper than the Alfine 11.

FreeFloat

Looks like the Alfine could easily deliver 24.8 inches through 101 on a 700X32, or 22.9 through 93.8 on 26X1.5.

With the 9-38 cassette and a long cage derailler I could get
22.7 inches through 95.7 on a 700X32, or 22.0 through 92.8 on 26X1.5.

Either way will work I guess.

I still like the idea of one visible cog and one chainring in the Alfine set-up after having logged thousands of miles on a bike sporting 18 rings and cogs in the past.
Then again 10X1 ain't so bad I guess.

Jeff Wills

I know the Capreo hub/cassette starts with a 9-tooth cog, and here's a 38-tooth cog: https://www.bikerumor.com/2010/07/22/...ette-sprocket/ , but I'm not sure both could be installed on a hub at the same time. That won't stop people from trying, though.

martianone

my road bike has a 38 t chain ring and 11-36 ten speed cassette, 327% as indicated with a top of just over 90 gear in and a low of 28.

FreeFloat

I knew IGH's were pricey, but list on the Alfine 11 hub only w/o even the shifter is $675 ($479 on Amazon)
I guess that's a relative bargain though, the Rholoff is over $1100!
Maybe the completes with Alfine are'nt as overpriced as I thought.

Still the 10X1 sounds easier to do.

fietsbob

Just long term 10 speed cassettes and chains, are the most expensive,
ongoing, and they do wear out.

whereas thicker and wider single speed cogs and chains on IGH drivetrains,
are at the opposite end of the replacement parts cost scale.

Rohloff cogs can even be flipped over, as can some of the Sturmey Archer flat cogs..
they are 3 spline pattern, and pretty standard for hubs by other companies..

doubling wear service life.
some cogs are dished, so flipping changes the chainline..