Shimano dynohub

Hello all

I've just had a look through some of the 79K+ posts on here, and it
seems someone can help me, somewhere!

My rear dynamo (no, they're not obsolete!) is about to fail, noisily,
and the front hub bearings are knackered. I was considering buying a
Shimano Nexus (NX-32) dynohub to sort both problems together. The
current hub is a 9 year old Deore LX Parallax. The questions:-

Where does a current Nexus hub fit with old Deore LX, quality wise? Is
this a serious downgrade, or not?

What sort of speeds do these dynohubs start to generate full power?
Parts of my commute have to be about walking pace, and I need full
lighting at that speed. I'm using a B&M Lumotec Plus lamp on the front,
and an AXA 3-LED lamp with battery cut-in at the rear.

--
Paul Boyd
http://www.paul-boyd.co.uk/

Paul Boyd wrote:
I've just had a look through some of the 79K+ posts on here, and it
seems someone can help me, somewhere!

I recokon there's more than 79K posts here. I've made 3400 odd, according to
Google:

http://groups.google.com/group/uk.re...rch+this+group


Where does a current Nexus hub fit with old Deore LX, quality wise? Is
this a serious downgrade, or not?

You can get dynamo hubs with Ultegra bearings as well. My bike has a Nexus
one on the front which works well, as a hub...

What sort of speeds do these dynohubs start to generate full power?

but I've yet to connect it up sigh.

Parts of my commute have to be about walking pace, and I need full
lighting at that speed.

It'll be as good as the rear mounted sidewall one, though.

Is the full lighting at walking pace to see your way on an offroad path? If
so, you may need more brightness, depending on your eyes.

--
Ambrose

Paul Boyd wrote:
Where does a current Nexus hub fit with old Deore LX, quality wise? Is
this a serious downgrade, or not?

This article may answer some of your questions:
http://www.vintagebicyclepress.com/VBQgenerator.pdf

Although it doesn't mention a Deore LX hub, it compares most of the hubs
that are currently available. The main disadvantages of the NX32 seems
to be relatively high drag when the lights are switched off.

What sort of speeds do these dynohubs start to generate full power?

I have a 3N70 dynamo hub with a B&M D'lumotec Topal front lamp and B&M
4D-Lite Plus rear. The front lamp produces plenty of light as I wobble
slowly up hills, loaded up with shopping.

Bob

Paul Boyd wrote:
Hello all

munch

What sort of speeds do these dynohubs start to generate full power?
Parts of my commute have to be about walking pace, and I need full
lighting at that speed. I'm using a B&M Lumotec Plus lamp on the front,
and an AXA 3-LED lamp with battery cut-in at the rear.

http://www.myra-simon.com/bike/dynotest.html

Might be of some help.

On 09/01/2006 18:31, Ambrose Nankivell said,

I reckon there's more than 79K posts here.

That's all my ISP had on their server!

Is the full lighting at walking pace to see your way on an offroad path?

Mainly on a segregated (ha!!) cycle path through a housing estate,
negotiating kids and unlit cyclists coming in the other direction on
their right, whilst still being able to see all the broken glass and
debris, and to be seen!

On 09/01/2006 18:37, Bob Johnstone said,
http://www.vintagebicyclepress.com/VBQgenerator.pdf

On 09/01/2006 18:38, Tosspot said,
http://www.myra-simon.com/bike/dynotest.html

Thank you both - that NX-32 seems to be a very draggy hub. Higher than
a certain speed, turning the lights ON actually reduces the drag. It
seems as if it will be OK for shopping bikes, but not more general
riding, so I think I'll be re-thinking that particular hub. The DN70
does look worth more than a second look.

Thanks again, chaps.

--
Paul Boyd
http://www.paul-boyd.co.uk/

I have one for sale on eBay, if you are interested:
http://cgi.ebay.fr/ws/eBayISAPI.dll?...tem=7210618703

"Paul Boyd" wrote in message
...

Thank you both - that NX-32 seems to be a very draggy hub. Higher than a
certain speed, turning the lights ON actually reduces the drag. It seems
as if it will be OK for shopping bikes, but not more general riding, so I
think I'll be re-thinking that particular hub.

Not the case at all IME.

I had an NX-10 for several years on my general purpose bike (*) - that is
the predecessor to the NX-30, and I think is the most draggy shimano hub out
there. In real life the losses mentioned don't amount to anything
significant - certainly nothing compared to a sidewall dynamo which was what
I had before.

I now use a SON, mostly because I've got more money than sense. You'll note
from the tests that with the light on, the SON has a pretty similar
resistance to the shimano, and the shimano has that resistance both on and
off. Well, I can't really tell if my lights are on or not by feel - they are
that good. (I couldn't tell with the shimano either). So I reckon you won't
notice the extra drag the shimano one gives.

(or is reported to give. I reckon they're better than Mr SON's tests say, ie
the resistance when off isn't as much as he says.)

(* used for a 10.5 mile each-way commute)

The bit which worried me more is your requirement for lighting at walking
pace. My front lamp is essentially out at walking pace - ie 4mph or less. It
gives some light at 8mph, which is as slow as I get to on a 1:8 hill - but I
don't really need light at that speed. If the path required me to go less
than 10mph, I would go elsewhere.

cheers,
clive

On Mon, 09 Jan 2006 17:53:26 +0000, Paul Boyd
said in :

My rear dynamo (no, they're not obsolete!) is about to fail, noisily,
and the front hub bearings are knackered. I was considering buying a
Shimano Nexus (NX-32) dynohub to sort both problems together.

I was warned of the NX-32 and managed to find an old-stock NX30. The
NX30 is excellent,. the SON is (of course) better.

Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken

Having sent back my hub as it was a. too wide b. felt like the bearings
were SNAFU'd , I tried spinning the front wheel of an Nx32 last night,
felt quite stiff. Not sure If I want to ride 100's of km losing all
that energy, especially in daylight. My jury is still out on the ideal
light, but I know it's not the poxy CatEye which died several times
(often downhill) yesterday.

MartinM wrote:
Having sent back my hub as it was a. too wide b. felt like the bearings
were SNAFU'd , I tried spinning the front wheel of an Nx32 last night,
felt quite stiff. Not sure If I want to ride 100's of km losing all
that energy, especially in daylight. My jury is still out on the ideal
light, but I know it's not the poxy CatEye which died several times
(often downhill) yesterday.

My SON does not feel like a regular hub when spun by hand, but once you
are cycing the tiny amount of resistence they say is there can not be
noticed even with lights on. The magnetic forces both repel and attract
the rotor so one spinning their repelling effect is cancelled out.