Spoke length calculation??

[bobg]

I'd be most grateful for any advice on this subject please.
I have a pair of unidentified stainless steel rims and a Sturmey Archer 3 speed hub which I plan to (try to) lace up for my old roadster rebuild. I have calculated the Effective Rim Diameter as 461mm using the guidance at http://lenni.info/edd/ and have confirmed the left and right flange as 65mm, the centre to right and centre to left as 27mm and the spoke hole as 2.4mm . I want 3x. The calculator on this site is based on Rinards one in the Jobst Brandt book and has some good feedback. The automated spoke length calculation arrived at when I feed all the figures in is 215.6mm.
I wanted to compare this answer with Rinards XL spreadsheet at http://sheldonbrown....rd/spocalc.htmt but I can't make head nor tail of it. If anybody out there is clever enough to have used it and can spare a minute to confirm the figure I have arrived at, I would be happy chap! It'd be a shame to destroy 36 nice Stainless spokes cos I got the length wrong!

 

[RecordAceFromNew]

I use spocalc. It says 216.6mm for 3x.

 

[XC26]

I'd be most grateful for any advice on this subject please.
I have a pair of unidentified stainless steel rims and a Sturmey Archer 3 speed hub which I plan to (try to) lace up for my old roadster rebuild. I have calculated the Effective Rim Diameter as 461mm using the guidance at http://lenni.info/edd/ and have confirmed the left and right flange as 65mm, the centre to right and centre to left as 27mm and the spoke hole as 2.4mm . I want 3x. The calculator on this site is based on Rinards one in the Jobst Brandt book and has some good feedback. The automated spoke length calculation arrived at when I feed all the figures in is 215.6mm.
I wanted to compare this answer with Rinards XL spreadsheet at http://sheldonbrown....rd/spocalc.htmt but I can't make head nor tail of it. If anybody out there is clever enough to have used it and can spare a minute to confirm the figure I have arrived at, I would be happy chap! It'd be a shame to destroy 36 nice Stainless spokes cos I got the length wrong!

I' found this one to be most useful:
http://houseof3d.com/pete/applets/wheel/appwheel.html

 

[bobg]

I use spocalc. It says 216.6mm for 3x.

Thank you so much RA, I knew you'd pop up from the ether That's interesting, the bloke who designed the "Lenni" calculator said he used spocalcs data and just made the interface easier. I'll have another look at Spocalc on the strength of that and try harder to make sense of it.
Not having tried a full wheelbuild before (and it's always been a stumbling block}, is 1mm critical in the great scheme of things, given that unless I can design an accurate spoke cutting jig and given that I need to measure from the centre of the "button " which is a bit problematic given the bend, then I'm sure to be a mm out here or there? Plus, is the thread usually the same length as the nipple, my LBS is kindly lending me his thread cutting jig.

Bob

 

[bobg]

I' found this one to be most useful:
http://houseof3d.com...l/appwheel.html

Thanks XC, I'll have a look at it now. I don't think Lenni covers assymetrical (sp) rims and I'm not clear about his workaround.
On the strength of RA's calc I tried Lenni again and it came out the same as spocalcs so I risk getting the cutters out soon I think

 

[bobg]

I' found this one to be most useful:
http://houseof3d.com...l/appwheel.html

It says I can't use it because I don't have a Java enabled browser.... Mozilla,

 

[PpPete]

, is 1mm critical in the great scheme of things, given that unless I can design an accurate spoke cutting jig and given that I need to measure from the centre of the "button " which is a bit problematic given the bend, then I'm sure to be a mm out here or there? Plus, is the thread usually the same length as the nipple, my LBS is kindly lending me his thread cutting jig.

Bob

I'd say a single mm is not critical. Commercially spokes are often only available in 2 mm increments anyway.
That said, I'd rather be 1 mm short on an old single wall rim, and 1 mm long on a modern box section rim.

 

[PpPete]

It says I can't use it because I don't have a Java enabled browser.... Mozilla,

Something dodgy on that site IMO
I have Firefox - but I know Java is enabled and I still get the same message
On Chrome it says I'm missing a plug-in but won't tell me which one or give me an option to download it.
IE won't connect to it at all

 

[bobg]

Thanks Pete. Maybe XC come back with a solution. In any event, as the one I used (which is simple) came up with the same spoke length as Spocalc ( which I dont think is simple) . I think I'll stay with the former.
I'll go a bit oversize on the cutting then I think. I have plenty of free time so if it goes tits up I'll start again. Still not sure how much thread to cut though. The existing thread is exactly the same length as the nipple and I'm presuming Raleigh wont have got it wrong....

 

[RecordAceFromNew]

Thank you so much RA, I knew you'd pop up from the ether That's interesting, the bloke who designed the "Lenni" calculator said he used spocalcs data and just made the interface easier. I'll have another look at Spocalc on the strength of that and try harder to make sense of it.
Not having tried a full wheelbuild before (and it's always been a stumbling block}, is 1mm critical in the great scheme of things, given that unless I can design an accurate spoke cutting jig and given that I need to measure from the centre of the "button " which is a bit problematic given the bend, then I'm sure to be a mm out here or there? Plus, is the thread usually the same length as the nipple, my LBS is kindly lending me his thread cutting jig.

Bob

Hi Bob in case there is any misunderstanding spoke lengths are always measured from the inside of the bend.

You can easily get nipples of varying lengths up to 16mm (and in different thread diameters!). Brass is best. Spoke threads are generally at around 10mm.

Btw assuming you are using rim brakes are you sure you want wheels with stainless steel rims?

 

[bobg]

Hi Bob in case there is any misunderstanding spoke lengths are always measured from the inside of the bend.

You can easily get nipples of varying lengths up to 16mm (and in different thread diameters!). Brass is best. Spoke threads are generally at around 10mm.

Btw assuming you are using rim brakes are you sure you want wheels with stainless steel rims?

My mistake RA, and thanks! Thats the one bit of info that I got from my LBS> Only 10 minutes ago I read in Gerd Schraner's book that it goes from the bend! So much contradictory info!...For calculating ERD, the Schraner book states" only by using the point at which the nipple head butts against the rim as a dimension factor, can precision be maintained" The notes from the DT Wheel building course say use the whole length of the nipple.... Bah

I have a pair of Westwood SS rims and extra long spokes ( to cut down and rethread) with original brass nipples from my "stock" My current restoration is a 1948 Raleigh Roadster with roller lever brakes, and it came with SS rims when it was a baby - till somebody nicked 'em

It's pretty much a labour of love anyway and not a bike I'll use much ... especially in the wet! I'd hang it over the mantlepiece if I was single...

Actually I dont find those leather impregnated Fibrax blocks too bad if I dont exceed 5mph and start braking 50 yards for a corner
I'd have preferred hub brakes but I've been looking for about a year for a bargain pair without success

BTW have you seen the new (old) Pashley Guvnor!! what fun, thats next on my list to replicate

 

[RecordAceFromNew]

Sounds like a super project to me!

I am no expert, but just in case didn't the 1948 Roadsters have 26x1 3/8 wheels? If so wouldn't 461mm ERD be too small by about 100mm?

I have no doubt whatsoever that your bike is going to be infinitely nicer than the Gov'nor, and I look forward to seeing some pics!

 

[XC26]

It says I can't use it because I don't have a Java enabled browser.... Mozilla,

I thought java was pretty much standard these days. Is java installed on your computer? It's free and easy to install. I'm using Mozilla Firefox (on Fedora Linux 14) and it works out-of-box..

The link below is a test site for seeing if your browser is java enabled:
http://javatester.org/enabled.html

It will also provide some assistance for getting java going.

Hope this helps.

 

[bobg]

Sounds like a super project to me!

I am no expert, but just in case didn't the 1948 Roadsters have 26x1 3/8 wheels? If so wouldn't 461mm ERD be too small by about 100mm?

I have no doubt whatsoever that your bike is going to be infinitely nicer than the Gov'nor, and I look forward to seeing some pics!

That's very optimisitic of you
It's the project after this so will be a while before I can collect all the components. Ideally I'd like an original ....

You had me at a disadvantage with that last post. I knew that the stainless steel rims I was using, although marked 26", were a little bit smaller, but was unsure how much so I just checked the ERD on an original 26" x
1 3/8 Raleigh rim and it came out at 478 which ( I think) means that the spokes would be 224.9 rather than 216.6 ie 8.3mm shorter. I may be wrong because I failed 0 Level maths in 1964 and there's been a lot of water under the bridge since then...

Bob

And thanks XC for the browser test, the site opened fine on my other (modern) laptop. This garage based one is ancient

 

[gwhite]

Something dodgy on that site IMO
I have Firefox - but I know Java is enabled and I still get the same message
On Chrome it says I'm missing a plug-in but won't tell me which one or give me an option to download it.
IE won't connect to it at all

Using Chrome I get it no problem.