Wheel Building - Double Snowflake

Afternoon ladies and gentlemen!
Hoping someone can point me in the right direction here - Ted, if you read this, i no longer have your number or Tom's so couldnt give you a buzz!

I am looking at building up a set of double snowflake or "flower" wheels.
Now, before i continue, yes i know it will cause the wheel to be super weak, prone to spokes snapping, going out of true all the time.....blah blah....i know.....
Im after some helpful advice and no bitching about the above points.
I work in a bike shop, im not bothered about stuff breaking...

Hubs - Condor Uno Black Hubs 32h
Rims - HP Deep V Black

Ok, so this is the pattern i am after;

Ive built maybe 40 standard 3x with a single or double "full twist" at the 3rd "x" with no problems, and never had anyone come back saying the wheels were out of true or problems bedding in. There are techniques for "pre-bedding" the spokes....

Now my problem is, i can not figure out the spoke length for my wheel build.
Standard 'flake is pretty easy, +2.5-3mm per full twist, but with this build the spokes travel aross the wheel left-right-left and right-left-right, so theres no "easy" way of guessing the length.

Second problem i found is, i can lace one side, but when i get to the other side, because the spokes arent bedded in yet and the twists havent tightened up, the spokes dont reach the nipples, and
if you add longer spokes, once tensioned up, are waaaaay too long.

So thats two issues i have found, so hopefully someone can help?

Maybe i should lace up one side, then the other with a 3x or radial for the time being, tension the spokes, loosen, remove the non 'flake side, then lace up with the new pattern, fingers crossed the other side would have bedded in by then, allowing me to use same length spokes that theoretically should now reach the nipples....

Any thoughts people?

Will buy a drink or two for whoever finds me a solution.

Cheers,
T.D

It seems like you are probably the most qualified person to answer you own question.

I doubt anyone else here would've built 40 snowflake wheels before.

It seems like you are probably the most qualified person to answer you own question.

I doubt anyone else here would've built 40 snowflake wheels before.

I have built a lot of wheels but never this specific pattern...
Im sure there must be a mechanic/wheel builder which has tried this pattern.

I have built a lot of wheels but never this specific pattern...
Im sure there must be a mechanic/wheel builder which has tried this pattern.

Have you tried Halfords ?

Have you tried Halfords ?

Im hoping you dont actually see Halfords as a bike shop.
I said mechanic or wheelbuilder, not a pikey using a wrench as a rattle....

Try PM'ing Arup on here

http://www.lfgss.com/thread41350.html

Nice pattern. I'm thinking you are way better than me but this may help. I recently laced a pair of three leading three trailing but with an extra weave near the hub. The only way I could get the second side spokes into the nipples was to push the rim down over the hub, and then use a long, 16mm, set of nipples. Once the spokes were all pulled in and the wheel settling down, I then one by one replaced the 16mm nipples for the normal 12mm ones. It was quite a struggle but the wheels look pretty cool once done. Good Luck.

Maybe i should lace up one side, then the other with a 3x or radial for the time being, tension the spokes, loosen, remove the non 'flake side, then lace up with the new pattern, fingers crossed the other side would have bedded in by then, allowing me to use same length spokes that theoretically should now reach the nipples....

I was just about to suggest this then I reread you post and say you have the same idea. I'd go radial for the ease of replacing the spoke with your new pattern.

When you have once side snow flaked and the other three crossed maybe don't un-build hate entire wheel but do a set of 4 spoke or what ever the minimum amount your can do as a "set"?

Does that make sense?

so do a snow flake from 3cross 1 set at a time? i understand...
Think i will do a normal full twist snow flake wheel set for now.
Will practise making the doubles with a cheaper rim and hub or the front wheel that survived when i got run over.
Once i get the technique down to an art, make a proper set for myself and others...
So many ideas....so little time...(and money! bloody pubs and alcohol!)

Yup, this a proper brain ache, I'd be tempted to double twist each crossing that you have single twisted there, because then each spoke still goes to the hole it would have gone to in a regular 3 cross. Working out the length would be easier I think....

+1 to Tommy's plan for temporarily radialling the one side. Please bring these to Wests for inspection and unbridled admiration when/if you do 'em please! Lovely and totally bonkers!

I suggest some form of therapy.

Sorry guys, been mega busy!
Didnt have time to faf around at home building wheels as i needed the bike to get around Ealing and to work! I just built up some normal snow flakes...no creaking, no ticking, perfectly true! Build them properly and they will never fail! ;)

*

*[URL="http://img541.imageshack.us/i/img0371h.jpg/"][/URL]

they look well good but a right fucking mare to build i bet!

Now my problem is, i can not figure out the spoke length for my wheel build.
Standard 'flake is pretty easy, +2.5-3mm per full twist, but with this build the spokes travel aross the wheel left-right-left and right-left-right, so theres no "easy" way of guessing the length.

In theory, the right-left-right thing shouldn't matter and 3 cross plus a bit for the twists should work. The paths followed by the spokes are roughly the same: each spoke follows all the sections of a straight path, they just happen to get their full set from several different (but equivalent) straight paths.

You can see that the wheel in the OP hasn't been properly tightened as there should be the same angle between each pair of spokes on each side of each twist. If it was done up tight the innermost twist would move closer to the hub and it would be more obvious what is going on. Making the twists slightly closer to the hub than they should be might help them end up in the right place.

(all this is theoretical - my practical wheel building experience is just a few plain 3 cross wheels.)

And another idea: add the twists in stages, inner twists first, just letting the spokes cross where the outer twists should be. Then add the outer twists one side at a time.

The long nipple trick above sounded good too, but you need to use nipples that actually have longer thread. I think DT swiss gain 1mm of thread for every 2mm of extra length, but as i understand it sapim nipples don't.

Another crazy idea: initially build each flange to a separate rim. Twisting one rim against the other should give loads of leverage for stretching the spokes.

Try this: 3 leading, 3 trailing, 3 cross, snowflake.

loose spokes in this photo)

Never seen it done anywhere else, and it worked fine.

How do you work out the spoke lengths required?

They look pretty. Could do with a rear brake.

Try this: 3 leading, 3 trailing, 3 cross, snowflake.

loose spokes in this photo)
Never seen it done anywhere else, and it worked fine.

Wow, that is nice!!!

Sam, that's really pretty. Any chance of some more photos of your wheel with the tension done up?

How do you work out the spoke lengths required?

It seems like it could be quite complicated as the length of spoke taken up by the twists depends on the angle between the spokes on either side of the twists, which depends on the length of the twists...

But i was thinking about this in the shower the other day, and had the idea that modeling the twists as if the spokes were fine thread winding around cylinders lying along the axis of the twists might work. On that assumption it's not too hard to modify the spoke length formula:

r = effective radius of rim = half ERD
f = hub flange offset
h = effective radius of hub = half distance between opposite spoke holes
d = diameter of hub spoke holes
s = number of spokes (total, both sides of wheel)
a = angle between spokes = 360/s in degrees, or 2pi/s in radians
w = width (thickness) of spokes at twists
ti = number of half twists on the middle cross
to = number of half twists on the outer cross

length = sqrt[ f^2

                + (r - h Cos(6a) + pi/2 w (ti Cos(3a) + to Cos(a)))^2
                + (h Sin(6a) + pi/2 w (ti Sin(3a) + to Sin(a)))^2 ]
             - d/2

Doing the sums for a Velocity deep V rim (r=291) on a miche large flange front hub (f=33.3, h=30, d=2.4), 36 (a=10 degrees) butted (w=1.8) spokes i get:

ti / to / Length
0 / 0 / 278 - i.e. a plain 3x wheel. agrees with http://lenni.info/edd/
0 / 1 / 280.8 - normal snowflake: adds 2.8mm per half twist
0 / 2 / 283.6
0 / 3 / 286.4
0 / 4 / 289.2
1 / 0 / 280.6 - 3 cross snowflake with twists on the middle cross
2 / 0 / 283.1 - adds 2.6mm per half twist for these
3 / 0 / 285.7
4 / 0 / 288.3
1 / 1 / 283.4 - the double snowflake, roughly a mix of both.
2 / 1 / 285.9
1 / 2 / 286.2
2 / 2 / 288.7

Making twists at the middle cross where the spokes meet at a larger angle adds less length. The 1 / 0 calculation should also work for Sam's 3 lead, 3 trail, 3 cross snowflake.

Using 2mm thick spokes increases the numbers to 3.1mm per outer twist, 2.8mm per inner twist.

I'd be interested if people who have actually built snowflake wheels could share their numbers.

^^Excactly as I suspected.

But i was thinking about this in the shower the other day...

Wow. My mind is usually fully occupied with following vexing question...

... 'oh, I suddenly need to wee. should I pop over to the loo risking slipping and coldness, or do I just hold on till I'm finished?' *

(* I dont wee in the shower. It stands in the same bath I use to bathe my kids.)
(OK maybe if they get me up really early. Little buggers)

I should admitt that I found that really interesting TBH Moth. Good work.

congratulation to sam. the 3 leading, 3 trailing, 3 cross, snowflake looks fantastic. till now I have only done two versions of the snowflake http://a.imageshack.us/img21/645/p1020538i.jpg and http://a.imageshack.us/img686/5174/p1020527u.jpg
I am very interested to try sam´s version!