# Alfine chainring/cog combos - long term reports?



## zanq (Feb 10, 2004)

I was planning to set up my Ogre with a 32T chainring and 18T rear cog with an Alfine 8 due to the bike mostly doing gravel grinding and light trails (do not plan to hammer up any steep climbs). I've read about guys having success with that chainring/cog combo despite it delivering too much torque for what the Alfine is supposed to handle. Are there any long term reports to the positive or negative with this setup?

As a side matter, I'm having some issues with my chain length vs. the tire size (FAT!) vs. the gear combo. With the Alfine hub optimally located in the dropouts, I get tire rub. If I add standard chain links and pull the wheel back, I have no tire rub but the axle is nearly at the end of the horizontal dropout. So I now need to try a half-link ($5) OR I move to a larger chainring (~$70 for a 36T Middleburn UNO), which may solve my chain length issue and according to this calculator (link), it puts the gear ratio in a "safer" zone.

If 32:18 is fine, the fix will be $5. If 32:18 is flirting with too much danger, the fix will be $70+.

Thanks!


----------



## Surly29 (Jun 8, 2009)

I ran my Alfine8 at 34T by 18T for the first year or so. It was my first IGH and I wanted it to bed in properly.

After that I ran 24T by 23T for over 3 years. Never any issues.

Personally, I don't believe in the "limited amount of input torque" thing. Shimano has never officially said anything about limits. I think more hubs are ruined from shifting under load (any load) than from torque inputs.


----------



## Velobike (Jun 23, 2007)

My Alfine 8 is at 32/20 and has been for 5 years. But that's not continuous riding - more like 3 months each year. (Rest of the time is singlespeed.)


----------



## PlutonicPlague (Jan 19, 2014)

I've got 3 bikes with A-8s:
Giant TranSend that came with 33/20. That's how Giant had it set up.
Pugsley with 26/19 (started out with 26/20, but that felt a tad low)
Krampugs (Pugsley rolling 29+ Rabbit Holes) with 30/22. Might try 30/21 to eek out a tad more high end.

So far, I've had no problems. My Pugs with 26/19 has the most miles, just under 1,000.

zanq, I'll bet you can go as low as 32/23 with no trouble. I seem to recall that vikb stated that he had put 5,000+ kilometers on his A-8 Pugsley, with no problems developing, using 32/23.


----------



## _CJ (May 1, 2014)

I run a 39/24 without any issues, and that's a lower ratio than 32/18.

In the interest of full disclosure, I did gack a hub earlier this year, but I'm blaming it on another component that failed. I have a belt drive with horizontal dropouts, and use aftermarket tensioners to maintain wheel placement / belt tension. The tensioner cracked, allowing the belt to loosen up, and it jumped while powering up a steep climb. I think the shock load of the belt jumping and reengaging is what blew up the hub.

I also agree with the Surly29 that shifting under load is probably the biggest culprit of failures. Just get used to making a momentary pause in pedaling while shifting, and you'll be fine.


----------



## zanq (Feb 10, 2004)

I was able to get out for a short test ride last night. Everything went well. Remembering to stop pedaling, shift, then pedal was and will be the trickiest part.


----------



## dru (Sep 4, 2006)

30/20 for at least a season and 30/19 before that. I've been working on a new career for a few years and only got the bike out a month back. The hub was clicking a lot more than I'd like after making a very loud crunch when shifting under power several years ago. I rode it for another 1/2 year with no issues but I decided to pull it apart on the weekend. Soaked it in gear oil and washed a lot of metal out and then split the internals. Found no damage, dipped it again and greased everything with white grease. Reassembled and it has never run smoother or quieter. This is the second service but the first where I split the internals. Runs better than new.

Drew


----------



## PlutonicPlague (Jan 19, 2014)

I'm running 30/20 on my Krampugs now, and it feels just right. Low is still low enough, and the faster high end doesn't feel too slow.
I'm old and slow, myself, so its a good match!


----------



## tedi (Oct 13, 2011)

In the quest to have low gear as low as 20 gear inch, i made a 23t cog out of loose cassette sprocket.
Combined with 36t chainring, it is doing fine..
Forgot to add. It is an alfine 8 on a 26" wheel kona unit. you know, the one with paragon slider dropouts


----------



## gregclimbs (Sep 21, 2006)

zanq said:


> As a side matter, I'm having some issues with my chain length vs. the tire size (FAT!) vs. the gear combo. With the Alfine hub optimally located in the dropouts, I get tire rub. If I add standard chain links and pull the wheel back, I have no tire rub but the axle is nearly at the end of the horizontal dropout. So I now need to try a half-link ($5) OR I move to a larger chainring (~$70 for a 36T Middleburn UNO)...
> 
> Thanks!


The cog size shouldn't make much if any difference. The issue is probably your chainline. With an alfine and fat tires in the ogre, you should be able to run it as fat as the frame will allow without chain run at all, all the way forward.

look at your chainline, check that the front chainring is in the correct position for a straight shot to the rear. And look at you cog and see if it is flat or offset. if it is offset, perhaps it is offset the wrong direction and you can flip it to get a better chainline.

regardless, you should be able to get it set up to run right to the bb, with fat tires and a straight chainline.


----------

