Hub Gears

[Andy230262]

Has anyone tried hub gears? I have a Bafang BBS02 and I was thinking of trying one . At the moment my chain line on on 9 speed cassette isn’t that good . Thought this may be more reliable and have less wear .

Shimano Alfine SG-S7001-8 Gear Hub 8-speed Disc Center-Lock silver | Bikester.co.uk

The Shimano Alfine SG-S7001-8 Gear Hub 8-speed Disc Center-Lock silver at Bikester.co.uk ✓ Biking specialists in the UK ✓ Buy online with free returns ✓ Easy shipping ✓ Great prices with the best service ✓ Find what you need with Bikester.co.uk ✓

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[Nealh]

I'm running one bike with alfine8 and twist /revo shift much preferred over derailleur gears and smoother imv. The A8 came off an mtb with bbs01 and a double ring set up, still using a double ring set up with alfine tensioner. Drive motor is G370 front hub.
I ignore the 2:1 ratio for gearing with 32/42t front set up.

 

[Andy230262]

I'm running one bike with alfine8 and twist /revo shift much preferred over derailleur gears and smoother imv. The A8 came off an mtb with bbs01 and a double ring set up.

is that one similar or better then the one I have a link to ? Also was there any issues fitting it ?

 

[Nealh]

Same model sg7001, no issues with fitting though all the ancillary parts have to be nexus/alfine compatible and the correct fitting kit for the wheel dropouts dependant if they are vertical or horizontal. Gearing jumps aren't equal and are fairly large.

Apart from the hub it self one needs wheel fitting kit inc the correct coloured locating washers, nexus/alfine sprocket 16t - 24t (18t is std), rear gear selector/shifter thumb or twist (must be nexus/alfine), if using twin chain rings one can use a std shifter or twist grip. The gears on the shifter work in reverse to usual gear shift so 1 is high gear and 8 is low gear.
Setting up the cable and adjustment is straight fwd, select 5th gear and when the cable is located on the wheel fitting make sure the pair of yellow/amber marks align 100% (when making the cable adjustment lightly nip the adjuster up on the cable and only fully tighten it once the the marks are aligned).

 

[Nealh]

Sprocket 't' size to approx. cassette gearing.
16t = 7/30t.
18t = 8/34.
19t = 9/36t.
20t = 9/38t.
21t = 10/40t.
22t = 10/42t.
23t = 11/44t.
24t = 11/46t.

 

[sjpt]

Has anyone tried hub gears? I have a Bafang BBS02 and I was thinking of trying one . At the moment my chain line on on 9 speed cassette isn’t that good . Thought this may be more reliable and have less wear .

Our Motus has Nexus 7 gears. Very effective.

It does make rear wheel removal quite a bit more of a faff. Luckily Marathon Plus tyres mean I hardly ever have to remove the rear wheel. Also no chain tensioner on our bike which makes keeping correct tension a bit more awkward.

 

[Nealh]

There are two different tensioners for nexus/alfine most parts are interchangeable,
one a simple short one (single pivot) and a second longer derailleur type (double pivot) if using double chainrings.

 

[Andy230262]

All looking positive. Are the gear changes smooth as with my 8 speed I have problem with the chain line on 1,2,3 gears and it isn’t smooth when changing .

 

[Nealh]

Alfine gear changing is smooth if it is set up correctly by aligning the Yellow marks during installation meaning getting the cable tension/length correct (not forgetting one has to select gear 5 on the shifter to as that it the set up process), If one changes gear under power then not so smooth esp with mid drive.
The advantages of changing down when stopped is a bonus.

A down side is the large jumps in gear ratio between gears, typically the jumps are approx. 1 - 4 sprocket sizes in higher gears and then when selecting low gears akin to changing from a 28t to a 38t in two unequal steps.

The internal gear ratios are fixed and can't be changed.
These are from low gear to high gear;
0.527, 0.644, 0.748, 0.851, 1.000 (5th), 1.223, 1.419 & 1.615.
To select the single rear sprocket to get the gearing that suit ones needs, divide the sprocket T size by each of the above ratios. By doing so one will get an approx. size of the gearing jumps and sprocket size if a real world gear cluster was being used, which equates to those in #5.

 

[Andy230262]

Alfine gear changing is smooth if it is set up correctly by aligning the Yellow marks during installation meaning getting the cable tension/length correct (not forgetting one has to select gear 5 on the shifter to as that it the set up process), If one changes gear under power then not so smooth esp with mid drive.
The advantages of changing down when stopped is a bonus.

If that is the case I don’t see how changing to a hub drive is any better. A part from the chain line. Thanks for that .

 

[Nealh]

If one is after close gear ratios then nexus/alfine is not the one.
As an example, in selecting a 20t rear sprocket the gearing/cog tooth size if compared to a normal gear cluster would be as the following:
1 st gear 37.95t
2nd 31.05t.
3rd 26.73t.
4th 23.5t.
5th 20t.
6th 16.35t.
7th 14.09t.
8th 12.38t

So as near as damn it one has gearing comparable with a 38/12t 8sp cassette but note the tooth size large jumps between gears. One can do the same maths for other size rear sprocket available to get a similar comparison, a smaller size sprocket reduces the jumps whilst going the other way they increase.

 

[Andy230262]

If one is after close gear ratios then nexus/alfine is not the one.
As an example, in selecting a 20t rear sprocket the gearing/cog tooth size if compared to a normal gear cluster would be as the following:
1 st gear 37.95t
2nd 31.05t.
3rd 26.73t.
4th 23.5t.
5th 20t.
6th 16.35t.
7th 14.09t.
8th 12.38t

So as near as damn it one has gearing comparable with a 38/12t 8sp cassette but note the tooth size large jumps between gears. One can do the same maths for other size rear sprocket available to get a similar comparison, a smaller size sprocket reduces the jumps whilst going the other way they increase.

Will have a look at what size rear cassette I have

 

[Nealh]

Changing to a internal hub gears has to be experienced to see any benefits, they weren't designed to be used under power motor load so use the motor gear sensor to momentarily relieve the load.
If one is a gear clunker and likes smashing the gears then hub gears are no no.
The chain alignment issue is their big advantage but the ease of use is also the other, smooth gear changing comes as second nature once one has used them a few times.
Their is none of the clunkyness of a derailleur system, no need to adjust H or L and less or no cable stretch.
Wheel changing /tyre /tube repair is longer and one needs to carry a 15mm spanner on journeys.

 

[sjpt]

The chain alignment issue is their big advantage but the ease of use is also the other, ...

ease of use: especially changing when stationary

 

[Artstu]

Has anyone tried hub gears? I have a Bafang BBS02 and I was thinking of trying one . At the moment my chain line on on 9 speed cassette isn’t that good . Thought this may be more reliable and have less wear .

The key to whether or not they'll work is how responsive the motor is, if it cuts power instantaneously like the bosch/shimano/yamaha motors it should be okay, if there is even the slightest delay it could make for an unrewarding experience.

 

[Nealh]

That's why the BBS have the option of a gear sensor to add.

 

[guerney]

The gear sensor on my BBS01b works very well indeed, glad I installed it. Power switches off instantly when you start the gear change, you get power very soon after the gear has changed. Occasionally on a steep hill in the rain, the power can turn on too soon, as on my particular bike the chain takes a smidge longer to move to the lowest gear in rainy conditions, while there is a lot of force on the chain (rear cassette). There are no settings in the firmware to adjust the gear sensor power timing, so I touch one of the brakes momentarily on a steep hill, to allow a little more time (saves horrible grinding). Overall, well worth buying. I wrapped waterproof self-amalgamating rubber tape around the gear cable at both ends of the sensor, to keep dirt out so that it keeps working well. 1,542 miles so far, no problems with the gear sensor.