Options for improving a dutch bike's hill climbing

For discussions about bikes and equipment.
steve browne
Posts: 111
Joined: 8 Oct 2009, 12:30pm

Re: Options for improving a dutch bike's hill climbing

Postby steve browne » 16 Jul 2020, 9:01am

I lowered the gearing on my Dutch bike by fitting an Efneo 3 speed front chainwheel. It has Sturmey Archer hub brakes and a three speed hub gear. Bit of a faff, and I haven't put the chain case back on yet but will get there in the end!

Jdsk
Posts: 2976
Joined: 5 Mar 2019, 5:42pm

Re: Options for improving a dutch bike's hill climbing

Postby Jdsk » 16 Jul 2020, 9:47am

I'd still like to know more about the user's needs and preferences.

Jonathan

cycle tramp
Posts: 891
Joined: 5 Aug 2009, 7:22pm

Re: Options for improving a dutch bike's hill climbing

Postby cycle tramp » 16 Jul 2020, 5:44pm

steve browne wrote:I lowered the gearing on my Dutch bike by fitting an Efneo 3 speed front chainwheel. It has Sturmey Archer hub brakes and a three speed hub gear. Bit of a faff, and I haven't put the chain case back on yet but will get there in the end!


Firstly, thank you very much for bringing this intriguing bit of kit to my attention. Up until now I didn't realise that it had existed and has been since 2017. It should have really been featured in the cuk magazine by now, simply because it sounds like the ideal piece of kit to exchange the gear range of any bicycle which uses a single chainring..
A quick google of 'efneo' brings up a number of good reviews.
Do you have the time and feel comfortable in posting your own thread on this forum about how easy it was to fit and if you've ridden it, what your thoughts are on it?

steve browne
Posts: 111
Joined: 8 Oct 2009, 12:30pm

Re: Options for improving a dutch bike's hill climbing

Postby steve browne » 16 Jul 2020, 7:12pm

I had one of the early versions, at which time there was a limited selection of bottom bracket axles available. My Dutch bike had a press fit bottom bracket axle. Nearly all of the time consuming fiddle was getting an axle to fit the frame. I removed the push fit bottom bracket, filed it to take a threaded bracket shell then installed a standard one which took the Efneo gearbox. If you buy one now you will probably not need to do anything like this as they have more bottom brackets available so it should be a really easy fit - they have videos on their website. I also note from looking at the website today that you can fit a Sturmey Archer bar end control (and therefore, presumably a Sturmey Archer three speed trigger) instead of the clunky looking changer that came with mine.

It has a good solid feel to it, has never slipped, changes reliably and gives a decent range of gears using a 22t rear sprocket (25.9" - 82.3"). Mine arrived without a means of changing the control cable. Current versions appear to include a cable splitter so this shouldn't be a problem. They had a few people trying to change the cables by themselves, getting into a mess disassembling the gearbox and failing to reassemble correctly. It is a pity there are no exploded diagrams provided with the gear but as it is not regarded as user serviceable that is fair enough! I always got prompt email replies from Wiktor when I got in touch about changing the cable and they sent me the cable splitter FOC.

I have not finished the project as I want to get a full chain case back on. I may opt for the Hebie chain glider as a last resort but I haven't given up yet!

Brucey
Posts: 41020
Joined: 4 Jan 2012, 6:25pm

Re: Options for improving a dutch bike's hill climbing

Postby Brucey » 16 Jul 2020, 7:34pm

Efneo gearbox is an interesting option, but it only gears up; good for small wheelers, not so good otherwise. Gear ratios are

First 1:1
Second 1.429
Third 1.786

This is the gear spread with 28T chainring, 20T sprocket, when coupled with a SA 3s hub;

http://ritzelrechner.de/?GR=SAAW&KB=50,40,28&RZ=20&UF=2185&TF=90&SL=2.6&UN=MPH&DV=gearInches

Sensible gear range, but from the theoretical 9 ratios, many of them are close duplicates (within ~6%), so effectively only five distinct ratios. And that combination of chainring and sprocket won't fit into that (or perhaps any) chaincase, either.

If the gearbox geared down from a middle ratio and also geared up (by a smaller percentage) then you could end up with gearing like this

http://ritzelrechner.de/?GR=SAAW&KB=53,46,30&RZ=21&UF=2185&TF=90&SL=2.6&UN=MPH&DV=gearInches

when coupled to a 3s gear, effectively giving a 1-1/2 step down and a 1/2 step up. In this case the chainring (46T) and sprocket (22T) would fit in the chaincase too. This would give gears from 29" to 91" with a 33% interval 1-2 and the remaining intervals of 15%, with eight distinct ratios, only one duplicate.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

steve browne
Posts: 111
Joined: 8 Oct 2009, 12:30pm

Re: Options for improving a dutch bike's hill climbing

Postby steve browne » 17 Jul 2020, 1:53pm

Screenshot 2020-07-17 at 13.49.05.png


All the technical drawings for this gearbox are online at the Polish Patent Office for those interested in this sort of thing. Patent number: PL 221732