SlimAgainSoon

I ride a bike with an internal-gear hub, as some of you might do, on my commutes. The hub — a Shimano Alfine — works well. The gearing, however, is too high.

I spend little time in the top gears (this is the Alfine 11-speed), and the lower gears aren’t quite what I need if I am humping it up a steep hill, especially if I’m carrying a lot of clothes and food for work or a load of groceries on the way home.

I decided to shift the gear range lower by installing a larger cog on the hub.

At first, I was puzzled — I couldn’t figure out how to remove the original cog (a 20-tooth).

With some help via a YouTube video — and, really, what a contribution YouTube makes to the lives of would-be mechanics and handymen — I got the 20-tooth off the Alfine and installed a 22-tooth cog.

Two little teeth, but a big difference. I’d recommend this to others who find the gear range pushed a bit to the high side for a commuter.

In fact, I’m now experimenting with a larger, 23-tooth cog (installed but heavy weather has kept me off the bike).

Once you get the hang of it, swapping cogs is easy. I found the larger cogs online, and they were not expensive ($8 or so).

The Alfine’s gearing might work fine for someone who doesn’t ride hills, or for the rider on a road bike (my commuting rig is heavier than a typical road bike), or the rider who is, well, more fit than some of us.

For me, swapping the gears allows dialing in a range that works better than stock.

scroca

Good info. Thanks.

Someday I expect to go with an internally geared hub. This advice may come in handy.

megalowmatt

I've put one on and swore I would never take it off it was such a pain. Did you get the special tool? If I remember correctly there's a lock ring under tension.

Dan Burkhart 

The "special tool" is a small flat blade screwdriver. Not difficult at all once you get the hang of it.

hueyhoolihan

it may prove beneficial to look at changing chainrings instead. it may be possible. although 8 dollars is pretty cheap, i've bought them new for just about that.

BobbyG

I, too, have thought about going "internal" for my next commuter. Is there a reason to not change the front chain ring vs the rear?

TransitBiker

From what i understand, the 11 speed was "geared" towards folks transitioning from a gear cassette, especially 2x# and 1x#.

My bike has a 18 tooth guy on the back, and i cannot imagine ever going 22. The lowest range available is fine for even the steepest hills around here. It all ready tops out around 22 on flats due to a relatively smaller chainring, but both the chainring & sprocket tooth cout are meant to work with the N360 hub. The N360 is about as much range as the 11 speed hub in question up to about 10th gear, which is why i even bring it up.

What kinda bike is this even on?

- Andy

kickstart

I have a 24 tooth cog on my commuter, but its an 8 speed nexus with a 46 tooth chain ring, and I ride on significant grades. After doing it a couple of times, changing the cog is quick and easy, only requiring a small screwdriver or pick.

I'm totally sold on IGH hubs for transportation cycling as they shift progressively at any time, rarely require any attention, and drive train components last longer. I can't imagine going back to derailleur shifting.

I-Like-To-Bike

Yes. It is cheaper, faster and far easier to change the rear. Takes all of 5 minutes, if that, once the wheel is off of the bike. It will take a few more minutes to add a few links to the chain, if necessary after adding a few more teeth to the gears.

dynaryder

And safety glasses,just in case.

SlimAgainSoon

Changing the cog was easy, but the first time I struggled with the lock ring.

To remove it, I used a special tool. I dug into my toolbox, way down deep, to get a lock-ring tool I needed to repair the stupid master cylinder on my stupid M.G. (many years back), and it got the lock ring off without much trouble.

It was of no use putting the ring back on. That took a while, fiddling with a screwdriver, but it popped on, eventually.

Second time, I skipped the special tool and went at it with a smaller screwdriver. Took some fiddling, but got it off. Harder getting it one.

Third time, E-Z off, E-Z on. Now I can pop off the lock ring and wiggle it back on quickly.

Funny thing ... I went to the YouTube video because I couldn't find the lock ring! It is hidden under a hard rubber bushing that pops off easily (same little screwdriver), but I didn't know what it was when I first saw it.

One interesting thing about the cogs — they are dished. You can flip the cog to move your chainline out a bit, which I did (the replacement cogs do not have the rubber piece attached to the side, which the original cog does. Can't flip the original, but you can the replacements.

Riding with the stock cog (20-tooth) I was maxing out over 25 mph, if I humped it on the flats, so the chainring (or wheels) must be larger size that what you have on your bike, TransitBiker.

My first Alfine hub, the earlier 8-speed version, came with the 18-tooth cog. On my bike, that was clearly high. I first swapped out the chainring, but was still hurting on the hills when carrying a load, so I then put on a 20-tooth cog.

My bike is a custom-built steel frame, with steel racks front and rear (and a generator hub up front, powering a mighty fine headlight and a taillight).

Because it is custom, I could get it with a special bottom bracket I can adjust to take out slack in the chain (the bike does not have horizontal dropouts like most internal-gear bikes).

This bottom bracket allows me to play around with different cogs without having to diddle with the chain, adding or deleting links.

I'm changing the cogs because I'm already at the limit on chainrings. I don't think I could get a smaller one on the crank.

Yes, I wear safety glasses when fooling with the lock ring. It can pop off and go flying!

Sullalto

Need to compare chainrings as well, for a fair comparison. Tire/wheel sizes, too.

ItsJustMe

You need to take the sprocket off to do the periodic maintenance of tearing down and relubing the hub anyway. The initial recommended interval is 1000km I think. I didn't do mine the first time until about 1400 miles, just before starting to use it this fall. I went with an ATF dip instead of grease. I think it helped a little but man, the IGH is still slow as molasses in January. I ride the road bike instead any day that the roads are clear and there's no snow or ice in the forecast.

The gearing on my Alfine 8 has been fine for me, in fact I never use either the highest or the lowest gear. I think I would be more likely to use the lower ones than the higher ones though, I wouldn't mind if I had an extra tooth or two in my rear cog.

TransitBiker

I'm comparing hub to hub. The chainring and wheel size I feel makes a smaller difference because they are larger rotational parts so adding or subtracting same % of size as the rear sprocket has an over-all lower effect. 26 to 29 wheels you might have a lower torque requiremrnt to get the bike rolling with 29, but climbing at a good pace may be slightly more difficult for the person providing the power all else being equal. Basically it just depends on where and by how much the leverage differentiates. I'm sure you could fiddle with different combinations of tooth count & wheel size (even tire height) to get identical torque requirements at the pedal. My point was basically that rear sprocket tooth count is key to the whole drive system, as it determines directly the end result of each gear ratio as you shift. A tooth or 2 on chainring I feel has less impact on drive output and more effect on the rider & fatigue time etc. That's just how I see it....

- Andy

Sullalto

Disagree, going from 26x2 to 700x32 can be worth a tooth in the rear, so you need to know what bikes you're comparing. Speaking of, the 3 alfine/nexus bikes I can think of offhand have 38, 42, and 46 tooth chainrings. Gaps like that you definitely need to be taking into consideration.

TransitBiker

Well, the solution to find that out is to use a gear inch calculator??

- Andy

MichaelW

I have removed and changed my rear sprocket a few times. I wonder if the circlip can be swapped for one with small tabs so I can use circlip pliers

TransitBiker

Checked my bike 26 vs 29. The gear inches went up by a little on the low end (harder acceleration from stop), and about 8 higher on the high end ratio (faster top speed on flats). This would make hills harder, acceleration harder, but higher nominal max speed. If you want to cancel that out, you'd need to go from 38 chain ring to probably 40 tooth. You can fiddle with it & see for yourself... Sheldon Brown's Bicycle Gear Calculator

like I said before, the bigger wheels are more difficult for climbing all else being equal, and one more sprocket tooth will decrease max speed & affect over-all end output ratio. If you think of the sprocket as part of the hub vs only chain ring & sprocket as a set, keeping in mind the larger wheel = more effort, you can more quickly assess if you're going to get the desired result. The main reason I jumped all over the n360, is because it does not have a fixed ratio that I'm stuck with. If I ever put it on another bike, I have some flexibility with the chainring & would leave the sprocket as-is. If you have a 8-11 speed hub, you can fiddle with wheel size, sprocket size & chainring size to get the optimal torque layout.

- Andy

fietsbob

Not to Me, IDK the OP's decision processes .

IMO, a bigger difference may be a smaller Chainring on the Crank End.

jputnam

I've seen that done, I imagine any good industrial supply shop could find you an eyelet-style retainer the right size.

I believe the standard ones are used simply because they don't get changed very often and don't require any special tools, even if the pliers-style tool is more elegant for those who have them.

Gresp15C

I suspect it's possible. It would be a bit of a puzzle to figure out the correct dimensions of the replacement, if the circlip has a round profile and the tabbed replacement is square.

I-Like-To-Bike

Correct. The suggested circlip with small tabs for this application is an elegant solution to a non existing/insignificant problem for anyone with a screwdriver.

tjspiel

Personally I would appreciate an inexpensive solution to this insignificant problem since I find putting these things back on to be a PITA. I'm sure you get good at it if you do it more than once I year, but once a year is about all I need.

Gresp15C

My technique is: Hold one end down with a finger, so it just hooks over the groove. Roughly opposite the finger, insert a small flat blade screwdriver and pop it over. There will be a bit remaining, that I just push over the edge with the screwdriver. This usually works 50% of the time which is good enough in my book.

To remove, I push one of the ends and scoot the ring around until the end is in one of those three cut-outs, then stick the same small screwdriver in there. Chasing it with a second screwdriver makes it even easier, like removing a tire with two levers.

SlimAgainSoon

Shimano made a number of changes when it redesigned the Alfine 8-speed into an 11-speed hub.

Oil lubrication, instead of grease, is the big one, but the one that mattered most to me (other than the extra gears) is I don't have to jab a spoke in a little hole to get the shift cable loose from the hub (which you have to do to remove the wheel).

With the 11-speed, Shimano added a little lever you grab, instead of creating a lever via the spoke (or small Allen tool).

Thumbs up, Shimano!

They could have, and should have, changed the locking clip so that it could be removed and installed with a circlip tool (as MichaelW and tjspiel suggested). Alas, that didn't happen.

But, the clip isn't hard to work, once you get the hang of it.

As for the comment re chainring change vs. cog change, as I noted earlier, I can't install a smaller chainring on my crankset.

Also, I don't see how changing the chainring is a quicker, simpler swap.

Once you've done it, changing the cog is a fast task.

It may look intimidating, but it is easily accomplished.