Dynohub question.

Seaswimmer

Hi all,

I have just taken delivery of a new front wheel with Shimano T670-3N dynamo. Its my first ever dynohub so not sure what it should feel like. Its not on the bike yet. It feels a tiny bit "rough" when I spin the wheel. Not free flowing like a normal hub. Is this normal for a Dyno hub. I expect a bit of resistance but not sure if this is what to expect.. It came from Rose bikes so their quality is usually pretty good..

Its possibly fine but I have nothing to compare it with so not sure

martyc5674

Seaswimmer wrote: »

Hi all,

I have just taken delivery of a new front wheel with Shimano T670-3N dynamo. Its my first ever dynohub so not sure what it should feel like. Its not on the bike yet. It feels a tiny bit "rough" when I spin the wheel. Not free flowing like a normal hub. Is this normal for a Dyno hub. I expect a bit of resistance but not sure if this is what to expect.. It came from Rose bikes so their quality is usually pretty good..


Its possibly fine but I have nothing to compare it with so not sure

Yes it should offer a kind of lumpy resistance when you spin it. Essentially your rotating magnets around some coils and of course they want to stay in one position so you're overcoming that resistance on/off/on/off hence the lumpy feel.

Marty.

Seaswimmer

martyc5674 wrote: »

Yes it should offer a kind of lumpy resistance when you spin it. Essentially your rotating magnets around some coils and of course they want to stay in one position so you're overcoming that resistance on/off/on/off hence the lumpy feel.

Marty.

Thanks. Lumpy is actually the perfect word for it..

CramCycle

Seaswimmer wrote: »

Thanks. Lumpy is actually the perfect word for it..

This said when you are on the road and you are moving over a certain speed, you won't notice this at all. It is only noticeable when you are spinning it or going slow (or sometimes when going super fast).

Weepsie

Sometimes you may forget, and think what on earth is wrong with my bike, but then be all smug with your always on, never need to be charged lights that are as good as most car lights!!

ted1

Perfectly normal. It's only 3Watt and say you use 200watts then it's only 1.5% of your power that you are lossing

Inquitus

ted1 wrote: »

Perfectly normal. It's only 3Watt and say you use 200watts then it's only 1.5% of your power that you are lossing

Less the inefficiencies in the system and its probably 3% of your power allowing for 50% efficiency!

benneca1

I built one up last year for night riding eventually i left it on always even during the day. Really cant say I notice the difference. Is lumpy when turn slowly but that's totally normal.

Seaswimmer

thanks all for the feedback. One more question. I got these 2 plastic devices. looks like the grey one fits into the black one and they fit snugly over the spade connectors on the dynamo. Is this just a protector for the connections on the dynamo when not in use.

I haven't got a light yet so not sure if they are required for connecting that??

CramCycle

Seaswimmer wrote: »

thanks all for the feedback. One more question. I got these 2 plastic devices. looks like the grey one fits into the black one and they fit snugly over the spade connectors on the dynamo. Is this just a protector for the connections on the dynamo when not in use.

I haven't got a light yet so not sure if they are required for connecting that??

Your wires go through the top of the grey one and fold back on little ridges, then you clip that into the black one and simply push onto the connectors on the dynamo. It means you do not need to solder anything and can easily disconnect the wheel if you have a flat.

Seaswimmer

CramCycle wrote: »

Your wires go through the top of the grey one and fold back on little ridges, then you clip that into the black one and simply push onto the connectors on the dynamo. It means you do not need to solder anything and can easily disconnect the wheel if you have a flat.

Interesting. no holes in the top of the grey one. Do they have to be punched out??

CramCycle

Seaswimmer wrote: »

Interesting. no holes in the top of the grey one. Do they have to be punched out??

The last time I done it, you just pushed the wiers through the little grey circles, image here: