http://citycyclingedinburgh.info/bbpress/ CityCyclingEdinburgh Forum » Topic: Dynamo Hub Question en Wed, 13 May 2026 04:30:57 +0000 http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102982 Wed, 06 Mar 2013 08:27:26 +0000 gembo 102982@http://citycyclingedinburgh.info/bbpress/ <p>Mr G used to service my nexus 8 hub at EBC But this became verboten, all they are allowed to do now is clean and re-grease it in a wee bath </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102980 Wed, 06 Mar 2013 07:53:49 +0000 Dave 102980@http://citycyclingedinburgh.info/bbpress/ <p>In case it's germane to the topic at hand: <a href="http://mccraw.co.uk/hub-dynamo-friction/">hub dynamo friction</a> by yours truly </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102954 Tue, 05 Mar 2013 17:42:05 +0000 DaveC 102954@http://citycyclingedinburgh.info/bbpress/ <p>Ah right I understand. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102952 Tue, 05 Mar 2013 17:33:49 +0000 Cyclops 102952@http://citycyclingedinburgh.info/bbpress/ <p>Both Shimano and Schmidt advise that their dynohubs are not user-servicable. People have replaced the bearings in Shimano hubs but be very careful - if you break the copper wire whilst bending it you'll most likely need a new hub.</p> <p><a href="http://dl.dropbox.com/u/3819048/Overhauling%20Shimano%20Dynamo%20Hubs.pdf">http://dl.dropbox.com/u/3819048/Overhauling%20Shimano%20Dynamo%20Hubs.pdf</a> </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102938 Tue, 05 Mar 2013 16:27:20 +0000 DaveC 102938@http://citycyclingedinburgh.info/bbpress/ <p>@Kappers, "The DH-3N7X/8X ones are their higher end of the range ones aimed at road and touring. These are the ones based on Ultegra brearings. I think 80 is just a lighter weight 70."</p> <p>Do you know if the bearings are chagneable on these DH-3D80 dynamo hubs? When I bought the hub I recall reading that the Son hubs were servicable but the Shimano hubs aren't? I'm guessing that this refers to the brushes on the rotor and not the bearings if it suffers from excessive use years down the line?</p> <p>Cheers, Dave C </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102802 Mon, 04 Mar 2013 18:23:25 +0000 Smudge 102802@http://citycyclingedinburgh.info/bbpress/ <p>So where does the deore xt dynohub fit into all these numbers and letters? :-s </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102770 Mon, 04 Mar 2013 14:55:14 +0000 Dave 102770@http://citycyclingedinburgh.info/bbpress/ <p>It's also worth keeping the resistance losses in perspective.</p> <p>Let's say you had a Nexus hub losing 6.5W at 30kph; the difference between a Continental GP3000 and Vittoria Open Corsa is 20W at the same speed (and these are both racing tyres).</p> <p>That data's a little stale but see <a href="http://www.rouesartisanales.com/article-1503651.html">here</a> for source. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102767 Mon, 04 Mar 2013 14:48:47 +0000 Wilmington's Cow 102767@http://citycyclingedinburgh.info/bbpress/ <p>Nah, non-disc in the end for various reasons. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102760 Mon, 04 Mar 2013 14:29:34 +0000 DaveC 102760@http://citycyclingedinburgh.info/bbpress/ <p>@WC.</p> <p>Did you get the Disc version? I did and have just taken the dumano hub off the Cotic to be put back on the Dawes for summer Audaxing.</p> <p>Dave (DH-3D80) C </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102757 Mon, 04 Mar 2013 14:20:36 +0000 kaputnik 102757@http://citycyclingedinburgh.info/bbpress/ <p>The NX- and DH-3N3X numbered Shimano hubs are in the Nexus series, which is the bargain / general purpose range from Shimano.</p> <p>The DH-3N7X/8X ones are their higher end of the range ones aimed at road and touring. These are the ones based on Ultegra brearings. I think 80 is just a lighter weight 70.</p> <p>There's a DH-3D series which seem to be for disc brakes.</p> <p>There's also a DH-T series where I think "T" stands for trecking and are based off of Deore LX components. By the looks of it they are similar to the 70/80 types but they just haven't bothered to lighten them up. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102752 Mon, 04 Mar 2013 13:55:00 +0000 DaveC 102752@http://citycyclingedinburgh.info/bbpress/ <p>Cheers Martin, I saw 3N70/80 and assumed it was the 80 family Andy was talking about. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102748 Mon, 04 Mar 2013 13:46:20 +0000 Cyclops 102748@http://citycyclingedinburgh.info/bbpress/ <p>"So the 3N80 is the lower end of the range?? What models are the upper end of the range for Shimano?"</p> <p>No the 3N80 is the top of the range. The 3N70/71/72 are essentially the same as each other with minor cosmetic differences.<br /> Just don't buy an NX-30 hub as they are draggy. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102740 Mon, 04 Mar 2013 13:15:51 +0000 DaveC 102740@http://citycyclingedinburgh.info/bbpress/ <p>So the 3N80 is the lower end of the range?? What models are the upper end of the range for Shimano?</p> <p>I didn't go for the SON as they were over twice as much. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102737 Mon, 04 Mar 2013 12:54:26 +0000 kaputnik 102737@http://citycyclingedinburgh.info/bbpress/ <p>The bearings in the non-lower-end-of-the range Shimano hubs (DN-3N70/80) are the same as found in their Ultegra hubs (according to <a href="http://www.peterwhitecycles.com/shimano3n70.asp">Peter White's dynamo pages</a>)</p> <p>I found that when I had the dynamo wheel built, the total weight of the rim and hub was less than the bottom-of-the-range Shimano clunker it replaced, and it felt freer spinning on the road.</p> <p>According to Peter White, "Energy required of the rider to rotate the hub when the lights are turned off at 30 km/h" is;</p> <p>Shimano Nexus - 6.5 watts<br /> Shimano DH-3N7/8 series - 2.2 watts<br /> Schmidt SON - 1.5 watts </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102729 Mon, 04 Mar 2013 12:37:32 +0000 Cyclops 102729@http://citycyclingedinburgh.info/bbpress/ <p>There is very slight drag with dynohubs but it's pretty imperceptible. For example, at 30kph a Schmidt hub requires an extra 1.5W effort from the rider compared to a normal hub - this is with the light switched on, it's considerably less with the light off. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102725 Mon, 04 Mar 2013 12:29:22 +0000 Smudge 102725@http://citycyclingedinburgh.info/bbpress/ <p>What they said^<br /> Also I noticed that when first fitted the wheel felt quite "draggy" and I assumed it was being caused by the dynamo, now it's had a few miles it's much smoother and must've just been the new grease/bearings etc settling in. Just like any other new hub really (doh!)</p> <p>My brain keeps telling me it must create drag, but when I freewheel it floats along in the usual roadbike fashion so I'm sure any "resistance" is purely in my head (badoom tish) </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102724 Mon, 04 Mar 2013 12:25:42 +0000 kaputnik 102724@http://citycyclingedinburgh.info/bbpress/ <p>Yes, it's perfectly normal. You won't notice when riding, but you will notice if you spin the wheel up by hand. It's just the inner magnetic witchcraft at work. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102720 Mon, 04 Mar 2013 12:18:04 +0000 DaveC 102720@http://citycyclingedinburgh.info/bbpress/ <p>Its normal.... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=9610#post-102716 Mon, 04 Mar 2013 12:10:05 +0000 Wilmington's Cow 102716@http://citycyclingedinburgh.info/bbpress/ <p>So I've got my shiny new hub (just got to sort out the rim and spokes now, as well as work out what to do for a rear wheel). Turning it it sort of 'clicks' (but without making the sound, if that makes sense) - I'm presuming that's normal? </p>