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PostPosted: Sun Jul 01, 2012 10:51 pm 
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Joined: Tue Jun 14, 2011 10:51 am
Posts: 254
Right...

I've ordered a set of tiagra 36 hole hubs, just over thirty quid for the pair.

Existing rim, alexrim ta19, measured as 607mm, measured as you described with a couple of spokes inserted.

I worked out the following:
Rear, shimano quote the 4600 as having 57.9 flange distance with a dish of 8.4, so apparently 57.9 /2 +- 8.4 dish gives 37.35 and 20.55 for centre to left and centre to right respectively, formula found on google search and seems to add up as only slightly off from the 4500 hub figures and results in same spoke sizes as previous calculations follows, with a flange diameter of 45mm

Nds is 293.8 and ds is 292.2

Front hub, tiagra 4600 shows flange distance of 71.6 so /2 is 35.8 centre to flange.
Flange diameter is 38mm

Result is 295.2mm spoke size

So with rounding off:

Front spokes of 296mm
Rear nds 294mm
Rear ds 292mm

I think I have that right.............


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PostPosted: Sun Jul 01, 2012 11:40 pm 
Retro Guru

Joined: Tue Jun 14, 2011 10:51 am
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Ok, checked prices, looks like sapim race all round and sapim strong on rear drive side as you suggested above

Comparing between the dt spokes from sjs and sapim from spa, saves about £14 :)


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PostPosted: Mon Jul 02, 2012 6:04 pm 
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That's why I use Sapim spokes, just as good as DT but half the price.

Good luck with the build!


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PostPosted: Mon Jul 02, 2012 11:03 pm 
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Joined: Tue Jun 14, 2011 10:51 am
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Cheers, and thanks for all the advice :)


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PostPosted: Tue Jul 17, 2012 10:59 pm 
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Joined: Tue Jun 14, 2011 10:51 am
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Finally got the spokes after a delay in delivery.

I've made a start on the front wheel, I'm using the forks of a bike on the work stand for trueing the wheel, works quite well as I've angled the bike right up so it's at a nice level and can turn it whichever way to save me bending too much.

Problems so far, perhaps one major one. It looks lie I've made a bad measurement somewhere, I can only think its going to be when measuring the erd of the rim. Once the spokes were laced on and in place it quickly became apparent they were a touch too long, I'm pretty sure they're laced correctly, but after initial tensioning the spokes are poking through into the rim by a good few mm, some just below the well of the rim where the tube will sit but hopefully the rim tape will protect that. My concern is that the nipples are threaded right down the spoke, if they were to go too far would it be obvious there was a problem? Would they just stop turning or twist the spoke if they ran out of thread or could I be doing some real damage and have impending failure on these spokes? I don't have a tensiometer but they seem tight enough and sort of ping when plucked, although all sound different.

Only other thing is that when trueing it, I've got rid of lateral movement, but the radial movement when looking at it spinning it sort of undulates a bit and really difficult to nail it down to a particular spot, I've strapped a tie.wrap across the forks for a visual guide and I think its only out by a mm or two, not worth worrying about? After all not a high quality rim and I read the tyre takes most of this out anyway....any thoughts?

Looks like the dishing is off, going to figure out a way to fix some kind of guide to the forks to centre it then will nee to true it again :)


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PostPosted: Wed Jul 18, 2012 11:03 am 
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I think this is always going to be a problem when building a wheel in your fork using zip ties. I canot see either how you will remove the upo down motion with out alot of trial and error and even then getting it round to within less than 1mm will be hard. A truiong jig really help here. A dishing tool makes dishing simple. If you get the wheel to with in 1mm ture and roun I am sure it will be durasble enough. Ideally you would get even tension and have much tighter tolerance but that is not going to happen with zip ties. Having built with the Sputnik the rim is not low quality at all as they true to very high tolerances while maintaining even tension.

I cannot speak for you spoke lengths as I have not measured your rim. What ERD measurment did you use? Did you measure the hub or trust the manufactures measurements? Hub measurements are less critical than the ERD. When measuring the ERD if your cut spoke has the nipple screwed down until it flush when the top of the soke then rounding up lengths will leave the top of the spoke poking through the nipple when the spoke is tensioned. Hense when doing ERD measurements only screw the nipple onto your cut spoke until the top of the cut spoke is sitting at flush with the nipple driver flats. I hope that makes sense. Also measuring the ERD in 4 places and averaging will highlight any errors and duff rims (you never know).

If you want free use of a turing jig then pop down to my shop but you may be far away. It is kind of difficult to diagnose ytour problems from a distance without seeing the wheel.

But perserverance is key. I can't remeber how long my first wheel took to build exactly, but that was with experienced instruction, professional tools and it still took half a day.


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PostPosted: Wed Jul 18, 2012 1:08 pm 
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Joined: Tue Jun 14, 2011 10:51 am
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Hi and thanks for the reply

It's not a sputnik rim, I'm using a couple of Alexrim ta19's which I had spare, removed the cheap hubs and spokes.

I'm not sure where I've cocked up the measurement yet, I'm tempted to strip it back down and remeasure from scratch, ive obviously gone wrong somewhere. I did take the measurement's for the hubs from the web site, but a cursory check last night and they look correct, I'll get the calipers on them tonight weather allowing.

I definitely measured with the measureing spokes threaded flush with the screw head flat groove, and I did it at two points across the rim, perhaps i should have done more.

i think, as it stands, (apart from the dish) it should be ok, my only concern being the fact the nipples are screwed right down the spoke shaft, i took one back off and cant see any damage but really not sure what effect it would have. Might just have to swallow my pride and order some shorter ones :?

A truing stand and dish stick would be nice but a lot of outlay when just having a go for the first time, although i guess if i never used them again i'd get most my money back second hand.

thanks for the offer, but am a bit too far but thanks anyway.

I can be stubborn sometimes, so even if this is an epic fail then i shall just try again :) I have the bits for the back wheel also but if the measuring was off they may need changing also.


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PostPosted: Wed Jul 18, 2012 1:16 pm 
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Well that the way you will suceed. Good luck.


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PostPosted: Wed Jul 18, 2012 1:44 pm 
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Like I said, it's annoying, but it's difficult to get the spokes right first time even with the calculators. I have a bunch of spokes where I've had to order another set - I think it's just experience when you know which ones to get. Luckily, I've been able calculate a length and then lace a wheel with my spare set and estimate what length I actually need.

If you're sure they are laced correctly, try to estimate how much they are too long and just order another set minus that amount.


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PostPosted: Thu Jul 19, 2012 9:37 am 
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Joined: Sat Apr 16, 2011 9:18 pm
Posts: 116
Location: Lancaster
A very useful website for wheelbuilding is WheelPro. It includes a SpokeCalc, here: http://www.wheelpro.co.uk/spokecalc/
I have the printed version of his book and it has been very helpful. The online version is £9 and probably worth it.

Ian.


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