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Need to know flange specs for wheel building. Probably being really dense but I can't seem to find them on the shimano tech docs site.
They're not on there & vary quite a lot depending on the model
Only takes 2 mins & more accurate to measure them yourself.
Bizarre they don't publish it. Bit of a pain to have to wait for the hub to be delivered so I can measure it before ordering the spokes. Ho hum.
Beter off doing it that way & not relying on what the manufacturers claim-they're not always the most accurate when it comes to hub & rim measurements (although rims are worse than hubs)
Curious, these things are manufactured to a spec, you'd imagine they'd be accurate to some pretty tight tolerances, especially for things like hubs. Can't seem to find measurements on the new Hope website either. DT Swiss have the info available for their hubs.
To be fair, hubs aren't usually far off, but rims quite often can be 1-2mm different on the claimed ERD to what you actually measure.
What doesn't help is also the differences in spoke lengths compared to claimed if you actually open a box & measure them.
these things are manufactured to a spec, you'd imagine they'd be accurate to some pretty tight tolerances
The parts are, ie: 3 examples of the same hub will all be within very close tolerance of each other.
But the published specs on the other hand can range from spot on to complete fiction.
Not to mention mid-season or minor revisions which can then mean all currently published specs are then wrong or need updating.
I've just been through this with a set of M756 hubs. Tried a couple of on-line spoke calculators and then went for 294 & 292mm spokes. They were way too long, ended up with 288 and 290mm in the end.
This page seemed to give the closest results for my rim / hub combo:
http://www.prowheelbuilder.com/spokelengthcalculator/
CRC and the free return saved the day. They were also the cheapest by a long way for the spokes (other than ordering from De)
But the published specs on the other hand can range from spot on to complete fiction.
Is bizarre that seeing as they are probably the most important bits of information for building a wheel from the hub.
like goldenwonder said though, hubs are normally ok, its rims that are often way out!
Unless you have the latest published specs direct from the manufacturer, ie: dont go on 2nd hand data from other site, you have no idea if the measurements you are using are even definitely for your hub, or if the manufacturer measures in the same way*, of course they all [i]should [/i]but that's no guarantee.
Mid season model revisions or year on year changes with no corresponding model name/number change can mean the specs you think are right are actually for some other version of the same part.
*again, more relevant to rims than hubs, but still, you'd be surprised !
Shimano Hub info can be found in Shimano Bicycle Components Trade sales & Support manual.
But saying that I am sure they measure flange form one flange to another and not from centre of hub to flange, (why they do it I do not know!)
And the rear is the same with a added "dish" measurment.
As a front Dura ace hub "flange Distance" is "74.0"
It can be worked out via maths but takes a while for the rear.
So above really best and quicker to measure them yourself.
Also as above spoke can vary in length from what is on the box (up to about 2mm)