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Tartridge

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Right. This is how you work out spoke lengths.

Measure the ERD of the rim (dont ask, just do it).

Measure 4 simple dimensions on your hub.

Download a spoke calculator programme for Excel.

Put the numbers in.

Read off spoke lengths.

Measuring your rim ERD:

Get 2 spokes and 2 nipples.

Thread the nipples onto the spokes til the end of the spoke is flush with the top of the nipple, loctiting it in place.

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Cut the spoke down to 200mm overall length (needs to be accurate to 1mm)

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Repeat, so you have two.

Pop them through opposite holes in your rim (valve hole and join are good markers) and measure the distance between the two ends with a ruler.

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Here it is 142mm. So you add on the 400mm of the spokes, making the ERD 542.

For mod wheels, theyre usually under 400 - so measure how much the spokes overlap by, and subtract it from 400. So thats 366mm in this case.

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This value goes into the 'ERD' field in your spoke calculator (more on that later)

Measuring the hub:

This is also very easy. All you need is 4 simple dimensions to a reasonable accuracy.

The dimensions you need are:

Centre of hub to Right Flange

Centre of hub to Left Flange

Diameter of Right Flange

Diameter of Left Flange

MTB rear hub spacing is 135mm - so halve this, and find a place on the hub that is 67.5mm from one of the ends of the axle (hub graphics/logos help here)

In this case, the bottom of the serial number is pretty close (68mm from the drive side end), so i'll use that.

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Measure from that imaginary marker to the middle of the Right Flange... bout 22mm in this case.

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And then to the left flange... bout 33-34mm.

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Then you need to do the flange diameters. This is from the centre of one spoke hole to the centre of the opposite spoke hole.

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Tis about 55mm here, its a bit skewed cos of perspective.

Do the left and the right flange.

Many manufacturers have these dimensions on their website.

Then click here if you have any common sense, and here if you are rather thick. Then click 'Open'. Click 'OK' if it gives you some bullshit about Macros and security levels.

I'll run through the 'thick' version... normal people will be able to work it out.

post-90-1091642764_thumb.jpg

Input no of spokes - easy.

Input the ERD you just measured.

Centre to flange... self explainatory - you just measured it. Do right hand side first.

Flange diameter - ditto - Right hand side.

Set spoke hole diameter to 2.4

Set X to 3 (not 2.5 as shown) for normal wheels. 2 and 4 can be used, but this is unusual.

The number in the bottom right is then your spoke length for that side of the hub.

Repeat using the 'Left Flange diameter' and 'Centre to left flange' dimensions to get the other side.

And... thats it! The end to all 'What spoke length?!' topics, woooo!! ;)

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Right a few links I've found whilst trying to find spoke lengths for someone (It's not as easy as simply "use the search"):

For all Hope hub info Use the spoke calculator here. Also has basic info for Mavic rims. Would also work if you know the details of other hubs (But it has Hope hubs built in).

Another basic one Here

The ERD of a Tryall rim (Front or rear - they're the same) = 534mm

The ERD is the only thing you need to know if you've got a Hope Hub, just use that site ^^^

"Hope" that helps :D

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  • 3 weeks later...
  • 1 month later...

Mavic ERD's from the dealer site:

Make sure you get the right one since Mavic seem particularly bad at naming their rims something sensible...

Cross Country

X717: 538.5mm

X517: 537.5mm

X618: 538.5mm

217: 537mm

217 D: 538mm

X317 :538.5mm

Cross Mountain

XM819: 532mm

XM719: 536mm

XM517: 538mm

XM117: 540mm

X3.1 : 532mm

F519 : 536mm

Extreme MTB

EX721: 532mm

D521 : 532mm

121 : 541mm

XM321: 536mm

EX729:534.5mm

D321:534.5mm

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Mavic ERD's from the dealer site:

Make sure you get the right one since Mavic seem particularly bad at naming their rims something sensible...

Cross Country

X717: 538.5mm

X517: 537.5mm

X618: 538.5mm

217: 537mm

217 D: 538mm

X317 :538.5mm

Cross Mountain

XM819: 532mm

XM719: 536mm

XM517: 538mm

XM117: 540mm

X3.1   : 532mm

F519  : 536mm

Extreme MTB

EX721: 532mm

D521 : 532mm

121   : 541mm

XM321: 536mm

EX729:534.5mm

D321:534.5mm

Most, if not all of those seem to be wrong (Y) For example, XC717 is 542.

If you want something doing properly, do it yourself

:P

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  • 1 month later...
  • 1 year later...

just to let people know, a hope mono on an alex dx32 26" 32 hole 3 cross will need 270 spokes and the old rear echo fixed hubs (ones with a fixed cassette for 6 gears) will need 269 DS and 271 NDS

oh yeah and check our chainreactioncycles for fecking cheap spokes, shame they dont come long enough for these wheels though!!!

Edited by spunkey_monkey_boy
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