Dynamos - Hub or Bottle?

For discussions about bikes and equipment.
Bmblbzzz
Posts: 2837
Joined: 18 May 2012, 7:56pm
Location: From here to there.

Re: Dynamos - Hub or Bottle?

Postby Bmblbzzz » 23 Jan 2019, 11:07am

Well found all those above! Slowster mentions the connector box, aka lego brick; I've never known these not come with the dynamo. Always best to check I suppose.

User avatar
mjr
Posts: 13790
Joined: 20 Jun 2011, 7:06pm
Location: Norfolk or Somerset, mostly
Contact:

Re: Dynamos - Hub or Bottle?

Postby mjr » 23 Jan 2019, 11:16am

Ontherivet77 wrote:Although, I accept/presume that hub dynamos are much better than bottles are they worth 10 times the difference.
Also, what is your experience with drag and weight with both these options?

Maybe not 10 times, but definitely worth the 3 times that they've fallen to lately. The main reason to use a bottle dynamo (and the Axa HR is a good choice IMO, with replacement rollers available) is if you have a strange wheel size that still has dynamo-friendly tyres available, such as 26x1 3/8", and only occasionally commute at night so the benefits of being cheaper than a custom wheel build and no drag in daytime outweighs the higher dynamo drag.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.

User avatar
pjclinch
Posts: 3768
Joined: 29 Oct 2007, 2:32pm
Location: Dundee, Scotland
Contact:

Re: Dynamos - Hub or Bottle?

Postby pjclinch » 23 Jan 2019, 11:17am

PH wrote:It's all been said so I'll just +1 it. I have three and don't notice the weight and drag, I know several people who bought hub dynamo wheels with the intention of swapping Summer/Winter, but none who have bothered once they realise the difference is so small.
IMO the only reason to choose a bottle dynamo is if for some reason you couldn't fit a hub version.


This. I had a Bottle on the 8-freight (which has single sided wheel supports and drum brakes). It was a pretty good BuM one, but was absolute pants compared to the dynohubs on the other bikes.

Pete.
Often seen riding a bike around Dundee...

roubaixtuesday
Posts: 2196
Joined: 18 Aug 2015, 7:05pm

Re: Dynamos - Hub or Bottle?

Postby roubaixtuesday » 23 Jan 2019, 11:20am

pwa wrote:Bottle dynamos are better when the dynamo is not being used. No drag. But I gave up using one about twenty years ago because it was very unreliable in the rain. It would slip on the tyre, meaning no light. Getting them not to do that seemed to be a black art. And in those days you were limited in tyre choice. Use the wrong tyre and you risked sidewall damage.


This - I used to use one and wouldn't touch them with a bargepole given the alternative battery and hub options available now. I'm sure you can get something *much* cheaper than that SJS option. Try Rose?

slowster
Posts: 945
Joined: 7 Jul 2017, 10:37am

Re: Dynamos - Hub or Bottle?

Postby slowster » 23 Jan 2019, 11:27am

Bmblbzzz wrote:Well found all those above! Slowster mentions the connector box, aka lego brick; I've never known these not come with the dynamo. Always best to check I suppose.

The posters on this thread https://forum.cyclinguk.org/viewtopic.php?f=5&t=125194&p=1280550&hilit=decathlon+dynamo#p1280550 who bought the wheel did not report that the connector came with the wheel, although some reported that the wheel did come with a QR skewer, contrary to the product description. Another poster who ordered a wheel plus a connector box for £3.50 received a bag of 10 instead of just the one :? .

User avatar
andrew_s
Posts: 4903
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Dynamos - Hub or Bottle?

Postby andrew_s » 23 Jan 2019, 2:53pm

mjr wrote:... still has dynamo-friendly tyres available, ... and no drag in daytime outweighs the higher dynamo drag.

It depends on what tyres you put on the dynohub wheel, but it's not unlikely that the extra drag of a tyre that's got a dynamo track will substantially outweigh the drag of a lights-off dynohub.
Differences in tyre drag can be 10W per tyre, a lights-off dynohub is 1-2W

User avatar
mjr
Posts: 13790
Joined: 20 Jun 2011, 7:06pm
Location: Norfolk or Somerset, mostly
Contact:

Re: Dynamos - Hub or Bottle?

Postby mjr » 23 Jan 2019, 4:11pm

andrew_s wrote:
mjr wrote:... still has dynamo-friendly tyres available, ... and no drag in daytime outweighs the higher dynamo drag.

It depends on what tyres you put on the dynohub wheel, but it's not unlikely that the extra drag of a tyre that's got a dynamo track will substantially outweigh the drag of a lights-off dynohub.
Differences in tyre drag can be 10W per tyre, a lights-off dynohub is 1-2W

Maybe read the whole post instead of cutting bits out to make it look wrong? :-P The "and" there came after me mentioning price as the primary reason to use a sidewall dynamo if you have a wheel size where cheaper ready-made dynamo wheels aren't available.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.

Ontherivet77
Posts: 220
Joined: 3 Jun 2009, 3:20pm
Location: Lancashire

Re: Dynamos - Hub or Bottle?

Postby Ontherivet77 » 23 Jan 2019, 5:14pm

Thanks for the replies.
A couple of follow up questions.
Is the Decathlon hub wheel good enough for a Ridgback Panorama (this is what I use for commuting).
Also, regards Shimano hubs what would you recommend and are there any ready made wheels you can recommend using Shimano hub dynamos?

Bmblbzzz
Posts: 2837
Joined: 18 May 2012, 7:56pm
Location: From here to there.

Re: Dynamos - Hub or Bottle?

Postby Bmblbzzz » 23 Jan 2019, 5:14pm

slowster wrote:
Bmblbzzz wrote:Well found all those above! Slowster mentions the connector box, aka lego brick; I've never known these not come with the dynamo. Always best to check I suppose.

The posters on this thread https://forum.cyclinguk.org/viewtopic.php?f=5&t=125194&p=1280550&hilit=decathlon+dynamo#p1280550 who bought the wheel did not report that the connector came with the wheel, although some reported that the wheel did come with a QR skewer, contrary to the product description. Another poster who ordered a wheel plus a connector box for £3.50 received a bag of 10 instead of just the one :? .

10 connectors for £3.50 sounds a bargain! I might order some even though I don't have any Shimano dynamos! (I'm not sure if the connectors are the same as the ones SP use?) Anyway, even assuming you only receive the one you order, at £3.50 it's probably worth ordering one as a spare/just in case.

User avatar
andrew_s
Posts: 4903
Joined: 7 Jan 2007, 9:29pm
Location: Gloucestershire

Re: Dynamos - Hub or Bottle?

Postby andrew_s » 23 Jan 2019, 8:29pm

mjr wrote:Maybe read the whole post instead of cutting bits out to make it look wrong? :-P The "and" there came after me mentioning price as the primary reason to use a sidewall dynamo if you have a wheel size where cheaper ready-made dynamo wheels aren't available.

I was just pointing out that the "no drag in daytime" advantage is very likely wrong.

I only quote the part of a post I am replying to or commenting on. I had nothing to say on price, so I removed the irrelevant content.
Far too many people quote whole long posts to comment on some little point that's lost in the middle, forcing the reader to re-read the whole quote to find out what was originally said.

User avatar
mjr
Posts: 13790
Joined: 20 Jun 2011, 7:06pm
Location: Norfolk or Somerset, mostly
Contact:

Re: Dynamos - Hub or Bottle?

Postby mjr » 23 Jan 2019, 10:41pm

andrew_s wrote:I was just pointing out that the "no drag in daytime" advantage is very likely wrong.

Depends if the tyres have dynamo tracks anyway. Most 26x1⅜" tyres I've seen do.
MJR, mostly pedalling 3-speed roadsters. KL+West Norfolk BUG incl social easy rides http://www.klwnbug.co.uk
All the above is CC-By-SA and no other implied copyright license to Cycle magazine.

Steve O'C
Posts: 49
Joined: 3 Mar 2013, 1:32pm

Re: Dynamos - Hub or Bottle?

Postby Steve O'C » 23 Jan 2019, 11:28pm

A couple of follow up questions.
Is the Decathlon hub wheel good enough for a Ridgback Panorama


The Decathlon wheel has a Shimano hub. I have had mine for 3 months and have done about 600 miles in all weathers. It has not given me any problem in that time. I paired it with this light;

https://www.spacycles.co.uk/m2b0s197p2030/BUSCH-and-MULLER-Lumotec-Cyo-IQ-Premium-T-Senso-Plus

Which is both brighter and has a better beam pattern that the cheap Lifeline light it replaced. I tend to ride with the light on day and night and I do not notice the extra resistance. I am however slow and overweight so YMMV.

For more money you could probably get a wheel with a hub that is lighter and more efficient with thinner spokes and a rim that is stiffer. When I first started using it I thought I could just detect some vibration from the hub on a short stretch of my commute that is on particularly smooth tarmac. It seems to have run in now and I no longer notice that. This is my first dynamo hub and I rather like the whole experience of battery free lighting. When the rim wears out I will probably buy a better hub and build it in to a lighter wheel. For the price I paid however I am not complaining.

I do not know if it is good enough for a Ridgeback Panorama but it is good enough for me.

User avatar
SimonCelsa
Posts: 579
Joined: 6 Apr 2011, 10:19pm

Re: Dynamos - Hub or Bottle?

Postby SimonCelsa » 24 Jan 2019, 5:29am

The posters on this thread viewtopic.php?f=5&t=125194&p=1280550&hilit=decathlon+dynamo#p1280550 who bought the wheel did not report that the connector came with the wheel, although some reported that the wheel did come with a QR skewer, contrary to the product description. Another poster who ordered a wheel plus a connector box for £3.50 received a bag of 10 instead of just the one :? .


Yes, I received the bag of 10 connectors when ordering what I thought was just one! I still think this was an error on their part. Anyhow, the surplus have been dispatched to good homes so have not been wasted. I can confirm they were 'shimano' plugs but also fit OK onto a SP style hub connector which I have on another bike.

De Sisti
Posts: 742
Joined: 17 Jun 2007, 6:03pm

Re: Dynamos - Hub or Bottle?

Postby De Sisti » 24 Jan 2019, 6:04am

I stopped using a bottle dynamo when the wire roller shredded my tyre (which had a dynamo track).
Not looked back since equipping my bikes with dynohubs.

brynpoeth
Posts: 11059
Joined: 30 Nov 2013, 11:26am

Re: Dynamos - Hub or Bottle?

Postby brynpoeth » 24 Jan 2019, 6:13am

Brucey wrote:bottle dynamos are almost extinct and the reason is that they are in nearly every respect inferior to a hub dynamo setup. You don't have to spend £250 on a posh hub dynamo wheel to find out if a hub dynamo will suit you or not; you can buy workable wheels from about £30 (eg in Decathlon).

cheers

I read that a bottle dynamo increases drag by up to 25%
Good way to save brakes going downhill :wink:
I think hub dynamos are much better
A bottle dynamo could come loose and go into the spokes, -1
Entertainer, juvenile, curmudgeon
Cycling-of course, but it is far better on a Gillott
We love safety cameras, we love life