# Half-step gearing with Alfine?



## ecoastjohn (Mar 9, 2008)

I'm in the process of converting my Racer-X to an Alfine hub. Since it's a FS bike I'm going to have to run some kind of chain tensioner to deal with the chain growth. 

Since I'm doing that I thought I'd add another chainring up front with just 3 more teeth and turn it into a half-step + IGH gearing. The Yess ETR-D tensioner should be able handle those extra 3 teeth easily and a 35-32 with an 18 tooth sprocket gives me a top end like a 44-14 and a low end like a 32-34 with 14 nice even steps in between (16 gears total).

Hopefully that "dangley" chain tensioner is smaller and tougher than a standard derailleur plus the small chainrings up front won't get caught up so often on ledges and trees, otherwise what's the point?

Anyone ever try something like that?


----------



## alanm (Sep 2, 2009)

Mate, I've done it with a Rohloff, works a treat. I run 38 / 34 on the front and the chain tensioner on the back is really short and given me no probs in many Km's.

Here's a pic of mine.

Al


----------



## ecoastjohn (Mar 9, 2008)

Very interesting looking bike with the trailer and the weird under-the-down-tube water bottle cage/fender mount.

Where's your front derailleur?


----------



## pursuiter (May 28, 2008)

ecoastjohn said:


> Anyone ever try something like that?


I've looked at it a few times, can't get half step gearing with an Alfine, the gear steps aren't even. With two frt chainrings you'll get many gears very close (1~2 inches) on the two rings. It does extend the range. The Rohloff and the IM9 can be set up with halfstep, the IGH steps are even:


----------



## EFMax (Aug 20, 2008)

I have gone 42/32 on a 18t Alfine and use the smaller ring for my off road stuff and the bigger ring for my road stuff.. Have found that before, I was on a 38T and a 18t. This now gives me an additional low gear and two higher gears.. I like this setup better now.


----------



## alanm (Sep 2, 2009)

Here you go



ecoastjohn said:


> Very interesting looking bike with the trailer and the weird under-the-down-tube water bottle cage/fender mount.
> *
> That bottle mount will take a 1.25L bottle, the fender is actually mounted under the fork, here's a pic of the whole rig.*
> 
> ...


----------



## ecoastjohn (Mar 9, 2008)

Here's the gearing you get with 34/32 chainrings.

Column E and the second chart are the gear-inches.
Column H and the first chart are the gear-differences.

Notice how the half-step gearing breaks up the big jumps into nice little ones with most being around 6-7%. There are still a couple in there that are 15%, but that's the typical change for most mtn bike cassettes and is similar to the Rolhf.

With this gearing I'm thinking you'll always be able to find the ratio that is "just right" and with the 2-tooth difference up front those shifts should be lightning fast and very reliable.

I think I'm going to give it a try since I've got to have a rear-tensioner anyways.


----------

