Spoke length sanity check and nipple help

Lumen

I'm ordering spokes for a wheel build, and not having done this before would appreciate a sanity check.

Hub specs:

Sturmey Archer S-RF5(W)
Specs for 111mm OLD
• Hub Shell Material - 6061 Aluminum
• Axle Diameter - 13/32” Slotted
• Axle Length - 148mm
• Over Locknut Dimension - 111mm
• Right Axle Protrusion Length - 19mm
• Left Axle Protrusion Length - 18mm
• Spoke Holes - 28
• Pitch Circle Diameter - 67mm
• Center to Flange Right - 23.8mm
• Center to Flange Left - 32.8mm
• Flange Width - 53mm
• Spoke Compatibility - 13g or 14g
• Sprocket Teeth - 13T through 22T
• Chain Line: 1/8” Flat 41.6mm
• Chain Line: 1/8” Dished 39.9mm, 43.3mm
• Chain Line: 3/32” Flat 41.3mm, 41.9mm
• Chain Line: 3/32” Dished 39.5mm, 43.7mm
• Indicator Chain - HSA651 Mark Green

The rim is a 16" (305) Dahon 28h rim. I can't really tell the offset from the pics (don't have it in my possession yet) so I've used zero offset for the calculator.

Spocalc gives me lengths of 129.9, 131.8
wheelpro gives me lengths of 130, 131.9.

I guess I should order 14 x 130mm and 14 x 132mm, plus a few spares. Does this look right?

The only place online I can find these spoke lengths is DT Champion spokes on wheelbuilder.com.

I also don't know whether I need 12mm or 14mm nipples. I'd prefer black brass.

JMJR

HI
unless the rim is deep vee type then 12mm nipples should do.
What lacing pattern are you expecting to use as it may be relevant to spoke length.
dahon seem to have a particular one that might be useful -The rear wheel features the same quality components with two cross spoke lacing on the rear drive side and radial spoke lacing on the non-drive side. Usually, dished wheels have unbalanced spoke tension which leads to compromised durability but with our unique spoke lacing, we end up with balanced spoke tensions and a stronger wheel.

John
ps. I will run your data on my spoke calc when I am at home tonight.

Lumen

Thanks. I'm proposing to use 1x. The rider is very light, his current rim is 20h and 1x on both sides.

I think it's 1x anyway. Each spoke crosses but does not touch one other spoke on the same side.

niceonetom

This is for an internally geared race-bike for a 5 year old, right?

Sanity check status: fail. Subject is insane.

Beasty

I like the way he tests his wheel-building skills on the kid's bike

doozerie

I don't know those rims but I would have thought that either of 12mm or 14mm nipples would do. The advantage of having both sizes to hand is that if your spokes are the right length then you can use the 12mm nipples but if your spokes are 1mm, and perhaps 2mm, short then you can use the 14mm nipples to make up the shortfall, but having both sizes is obviously overkill if your spokes are the correct length to start with.

Here is yet another spoke length calculator. It may not be of any extra help but the How to measure link is useful and possibly more user friendly than the Wheelpro instructions.

Based on your figures above, then yes the 130mm and 132mm lengths should be what you need, assuming that you fed in all of the correct measurement info (which can be very tedious and therefore prone to errors so worth checking twice).

doozerie

Oh, and are you sure you've dug out the correct ERD for the rim? Perhaps Dahon make that information readily available but I've had a hard time finding it for Mavic rims in the past so I've often had to rely on measuring it myself.

Lumen

doozerie wrote: »

Oh, and are you sure you've dug out the correct ERD for the rim? Perhaps Dahon make that information readily available but I've had a hard time finding it for Mavic rims in the past so I've often had to rely on measuring it myself.

ERD is like the ISO measurement, right? No wait, that can't be right because deep section and shallow section rims have the same ISO but different spoke lengths.

I can't find any technical information for the Dahon rim. I've attempted to join the Dahon forums but am waiting on "administrator approval".

Maybe I'll just have to measure the damn thing when it arrives.

edit: I think maybe the 305 is the ETRO not the ERD.

Holyboy

Lumen wrote: »

ERD is like the ISO measurement, right? No wait, that can't be right because deep section and shallow section rims have the same ISO but different spoke lengths.

I can't find any technical information for the Dahon rim. I've attempted to join the Dahon forums but am waiting on "administrator approval".

Maybe I'll just have to measure the damn thing when it arrives.

edit: I think maybe the 305 is the ETRO not the ERD.

Yup,you're right about ETRO being 305 nothing to do with the ERD I had a quick look but can't find any ERD measurement for the rim probably because it's a replacement part and they don't expect people to build wheels from scratch with their rims, once you get it it's easy enough to measure though but it's the internal measurement you want, that's from inside the spoke hole to inside the opposite spoke hole,I have a tool I made to do it if you want but it doesn't have to be THAT exact,if you're calculating spoke length online most people use a few sites and take an average I like D.T. Swiss spoke calculator but the spokes seem to come up long from time to time or I can send you a really,REALLY complicated equation to work it out!!!

JMJR

i have found this calc very useful, in fact I liked it so much I bought the book!
john

http://www.wheelpro.co.uk/spokecalc/

As said above you have to be sure on the effective rim diameter ERD to be able to depend on the calculated spoke length.
john

Diarmuid

That's a coincidence. I was measuring a hub and rim tonight to pick out some spokes.
Here are spokes from the UK that will suit you. I ordered some DT Champion spokes from them

JMJR

@ OP
You have a pm.
john

uberwolf

niceonetom wrote: »

This is for an internally geared race-bike for a 5 year old, right?

Sanity check status: fail. Subject is insane.

guess that means it's a crank based power meter installation

Lumen

Diarmuid wrote: »

Here are spokes from the UK that will suit you.

British made too - God Save The Queen! :pac:

doozerie

Lumen wrote:

ERD is like the ISO measurement, right? No wait, that can't be right because deep section and shallow section rims have the same ISO but different spoke lengths.

No, the ETRTO/ISO measurement is the bead seat measurement so only useful for determining what tyres will fit on the rim. The ERD is less than that, it's a measure of the distance/diameter from outermost face of one nipple head to outermost face of opposite nipple head, and the nipple should always sit lower in the rim than the tyre bead hence the smaller measure compared to ISO. Some manufacturers state the ERD for (some of) their rims but they are not always reliable so the safest bet is to measure it yourself, which is a pain of course as then you can only buy the spokes after you've already bought and taken delivery of the rim. If you buy the spokes based on the ISO measurement then they will be too long.

And unfortunately the ERD really is critical to calculating the correct spoke length, but can't be derived mathematically as far as I am aware, which makes it even more annoying that so few rim manufacturers publish reliable ERD figures. Individuals on the Internet can be a misleading source of accurate ERD figures too, as it seems like different people measure the figure differently and some people are happy to rely on a measure which leaves a few mm of spoke protruding from the nipple while others are not. I've ended up with a self-built wheel where the spokes protruded like this on one occasion because I trusted the spoke length suggested by a local bike shop when buying the parts for the wheel - it worked fine as a wheel, when fitted with decent rim tape, but definitely best avoided if possible.

pprendeville

Can someone recommend where I can get brass nipples? On my phone here and can't seem to find any Irish sellers or can't find them on CRC (only aluminium ones).

Diarmuid

http://www.starbike.com/p/Sapim-Hexagonal-brass-nipple-1253-en

pprendeville

free shipping to ireland on orders over 500 quid. anyone else need spoke nipples?

macnab

Have you considered stripping an old wheel for parts?

doozerie

www.sdeals.com, in the UK, might be worth contacting. They don't list nipples as a specific item on their website but when I bought spokes from them recently the nipples were in a regular ziplock bag so presumably they have a stock of them that they dip into as needed. I found them very helpful to deal with, and being a very small company they might be more able and likely to sell you just the nipples as a one-off.