Lower gearing

[Pale Rider]

The gearing on my trekking bike is too high and I would like to know what practical difference a smaller front chain ring would make.

Current set up is an Alfine 11 hub, 20t rear sprocket and 42t on the front.

The rear sprocket is as big as you can get, but first still equates to about 7mph with reasonable cadence - it's too high to grind up really steep hills.

There's a good choice of smaller rings for the front: 40t, 38t and 36t.

How much difference will dropping two teeth make?

Working out gear inches doesn't help me because I don't know enough to interpret the results.

I'm no speed merchant, so there's a bit of headroom at the top end to work with - I normally bowl along in sixth or seventh.

All comments - apart from lose weight and get fitter - appreciated.

 

[Cush]

A fair bit solo but I haven't tried it out on any real long steep hills or fully laden with panniers since I made the change in October.

 

[albion]

36 is only 16% easier. Obviously 40 is a tiny one quarter of that 16%.


A 4% change will grind again...

 

[Cycleops]

You seem a bit stuck for choice, maybe one of the disadvantages of the Alfine hub. The only way would be with a 36t front ring which should give you a noticable but not huge improvement.

 

[byegad]

Yup. You have a problem if 42 up front gives 7mph at a decent cadence then 36 will give you 6mph at the same cadence. (36=6x6 and 42=7x6) You will similarly lose 1/7 th of your top speed in top gear but you say that's not an issue.

 

[Pale Rider]

Very helpful - and insightful - replies.

There's plenty of stuff online about the Alfine 11 being too high geared, even though the range looks good on paper.

At least I now know changing to 40t or 38t is hardly worth the bother.

So it's either 36t or put up with it as is.

 

[Pale Rider]

...update...

I've changed the 42t front ring for a 36t.

As correctly predicted by those who replied, there is a small, but noticeable difference.

I can now spin first gear at 6mph or even a shade under.

Top now equates to about 22mph, which would be too slow for some, but not me.

The change only cost £30 fitted, so I'm happy with that.

If this gearing chart is to be believed, the Rohloff hub has three lower gears than first on my Alfine 11.

I think that illustrates first on the Alfine 11 is too high, unless you run a small front ring.

http://www.nuvinci.com/Docs/GearInchChart_N360.pdf