SP dynamo hubs - narrow flange spacing

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Boogaloo
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SP dynamo hubs - narrow flange spacing

Postby Boogaloo » 3 May 2019, 10:00am

I'm considering one of these as they seem to be relatively inexpensive and light. Certainly compared to my Son 28.
However they do seem to be very narrow with 50mm between the flanges. Has anybody seen this as a problem?
A quick look at my other front hubs and they are somewhere around 65 - 70mm
I'd be building a 700 rim brake wheel.

Many thanks
Paul

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Mick F
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Re: SP dynamo hubs - narrow flange spacing

Postby Mick F » 3 May 2019, 10:24am

I built one into my Moulton front wheel. Not 700c of course but 406 (20inch).
No issues whatsoever.
Mine is a 28h version.
Mick F. Cornwall

amediasatex
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Location: Sunny Devon! just East of the Moor

Re: SP dynamo hubs - narrow flange spacing

Postby amediasatex » 3 May 2019, 10:37am

They are narrow, and yes wider would be better, but I don't think it's a major problem for normal use.

I've got a few thousand miles on one (32h) on an 700c audax bike with no issues whatsoever, and I have several friends with them, and know of at least a dozen others locally through workshop and club, most on road bikes but a couple on MTBs, only issues of note have been bearing related on early ones and all fixed under warranty, no spontaneous collapsed wheels or anything ;-)

If you are particularly heavy, or were planning on carrying very heavy loads I might consider an alternative from Shimano or SON, and I certainly wouldn't build a low spoke count one, but for an unladen or lightly laden bike I would have no issues recommending them as good value with decent performance.

Brucey
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Joined: 4 Jan 2012, 6:25pm

Re: SP dynamo hubs - narrow flange spacing

Postby Brucey » 3 May 2019, 11:10am

it'll be OK provided you don't use a flimsy rim and/or go nuts with the spoke tension.

BTW the flanges are about the same distance apart as in many rear hubs.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

pwa
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Re: SP dynamo hubs - narrow flange spacing

Postby pwa » 3 May 2019, 11:28am

I have one on the front of my tourer, with tourer style rims and 36 spokes, and the wheel has held up nicely. No brake rub or any other sign of things going wrong. I did worry about the narrow spacing but in practice it seems okay. And when you think about it, unlike with a rear wheel the spoke tensions are the same left and right so the front wheel starts off with an advantage.

Samuel D
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Re: SP dynamo hubs - narrow flange spacing

Postby Samuel D » 3 May 2019, 12:31pm

On the other hand, front wheels experience higher lateral forces, I think in normal riding (landing after hopping kerbs with the handlebar not quite straight, honking while swerving, etc.) and certainly in crashes. You don’t often see a rear wheel wrecked from side forces. You see front wheels destroyed in this way fairly often, e.g. crashes in races.

To improve your odds of not crashing when you touch wheels with the rider in front, you can forcefully drive your front wheel through the rider’s rear wheel, knocking his wheel sideways (from which he – or rather his inherently stable bicycle – will recover) to keep the contact patch under your centre of gravity and therefore maintain your balance. This puts large sideways forces on the wheel.

I built a 36-spoke Shutter Precision SV-9 into a wheel. I chose 36 spokes because of their shallow bracing angle with this hub. I’m light and the wheel hasn’t given me problems, but that doesn’t mean I wouldn’t prefer wider flange spacing. But you can’t [inexpensively] have everything you want …

Boogaloo
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Re: SP dynamo hubs - narrow flange spacing

Postby Boogaloo » 3 May 2019, 12:41pm

Thanks for the responses. I feel reassured and will avoid wheelies and parking it in one of those concrete slot type bike parking things!

bgnukem
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Joined: 20 Dec 2010, 5:21pm

Re: SP dynamo hubs - narrow flange spacing

Postby bgnukem » 3 May 2019, 12:46pm

Problem I found with mine is the spokes are too far away from the fork leg to allow a cycle computer sensor to work properly!

zenitb
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Re: SP dynamo hubs - narrow flange spacing

Postby zenitb » 6 May 2019, 2:10pm

I built up my SP dynamo wheel two years ago an have done about 4000 bumpy, muddy canal commuting miles on it so far with it staying 100% true - no need to re-true so far. Have done a couple of short UK camping tours on it and am taking it touring in France next week..

My wheel is 26" with 36 spokes though...so easier to make a strong wheel I guess ...and I use 1.75" wide tyres so it gets cushioned to an extent.

Here is my write-up of the wheelbuild..

http://zenit-b.blogspot.com/2017/02/shu ... build.html

AndyA
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Location: Edinburgh

Re: SP dynamo hubs - narrow flange spacing

Postby AndyA » 6 May 2019, 8:33pm

I built a wheel for someone using a previous generation Mavic Open Pro and a SP dynamo, Sapim DB spokes. It folded hitting a pothole at speed while they rode back from the pub. Might not have folded with a tougher rim, might not have folded with a wider spaced hub, might not have folded had they not been lubricated. I won't build another lightweight 700c rim using that hub

pete75
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Re: SP dynamo hubs - narrow flange spacing

Postby pete75 » 6 May 2019, 9:07pm

AndyA wrote:I built a wheel for someone using a previous generation Mavic Open Pro and a SP dynamo, Sapim DB spokes. It folded hitting a pothole at speed while they rode back from the pub. Might not have folded with a tougher rim, might not have folded with a wider spaced hub, might not have folded had they not been lubricated. I won't build another lightweight 700c rim using that hub


I remember reading about this some time ago on Harry Rowland's old website.
Found it on wayback

"SON DELUX and Shutter Dyno Hubs have a very narrow flange to flange measurement and don't buid in to 700c rims well. They are weak, unstable or even possibly unsafe. I WOULD NOT build it, so please don't ask me.
SON 28 & Klassic are fine with 700cc rims. "

https://web.archive.org/web/20160307085 ... and.co.uk/

Samuel D
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Location: Paris

Re: SP dynamo hubs - narrow flange spacing

Postby Samuel D » 6 May 2019, 9:43pm

AndyA wrote:I built a wheel for someone using a previous generation Mavic Open Pro and a SP dynamo, Sapim DB spokes. It folded hitting a pothole at speed while they rode back from the pub.

Spoke count and approximate rider weight? I’m 65 kg and used 36 spokes.

AndyA wrote:[…] might not have folded had they not been lubricated.

What was lubricated? The rider with ale?

AndyA
Posts: 386
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Location: Edinburgh

Re: SP dynamo hubs - narrow flange spacing

Postby AndyA » 6 May 2019, 10:46pm

Samuel D wrote:
AndyA wrote:I built a wheel for someone using a previous generation Mavic Open Pro and a SP dynamo, Sapim DB spokes. It folded hitting a pothole at speed while they rode back from the pub.

Spoke count and approximate rider weight? I’m 65 kg and used 36 spokes.

AndyA wrote:[…] might not have folded had they not been lubricated.

What was lubricated? The rider with ale?


32 spokes, approx 75kg, cider

pwa
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Re: SP dynamo hubs - narrow flange spacing

Postby pwa » 6 May 2019, 11:12pm

I remember folding an MA2 rim on a normal width hub after skidding on spilt diesel oil, so I'm not sure we can say it happens because of narrow flange spacing. It happens because you put unusually high lateral forces on a wheel in an extreme situation. But wider flange spacing might conceivably allow you to get away with it sometimes.

ANTONISH
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Re: SP dynamo hubs - narrow flange spacing

Postby ANTONISH » 7 May 2019, 8:04am

I built one with an open pro rim about 18 months ago.
It's been fine, I use it for audax in the winter and I've toured on it.
Flange spacing is narrow at 50mm but the flange spacing on a rear hub is only around 55mm and with dishing and the fact that it has to cope with being the drive hub I would assume there is more stress involved.