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BERD Polymer spokes


Rusevelt

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  • 2 weeks later...

Thanks Luke, thanks Mike! I must admit I'm really pleased with that joint and the colour, looked amazing in the sun today. 

 

Many hours of faffing with rope later...

20211202_144408.thumb.jpg.93791f7b722481caa2e4b071e59ca60d.jpg

I am told the spoke tension will drop now as the spokes creep, so it'll need a retension tomorrow.

Can add more details / photos if anyone is interested (Y)

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On 12/2/2021 at 6:04 PM, Adam@TartyBikes said:

Thanks Luke, thanks Mike! I must admit I'm really pleased with that joint and the colour, looked amazing in the sun today. 

 

Many hours of faffing with rope later...

20211202_144408.thumb.jpg.93791f7b722481caa2e4b071e59ca60d.jpg

I am told the spoke tension will drop now as the spokes creep, so it'll need a retension tomorrow.

Can add more details / photos if anyone is interested (Y)

Absolutely love it! Can't wait to hear how they feel on the bike. Does make me wonder how they'd perform on a trials wheel as well? 

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Contact would lead to additional abrasion too, presumably? As it stands there's some (unavoidable) contact with the loops at the hub end which won't really move around anyway, but otherwise mid-spoke (where any real movement will be) there should be minimal friction so provided you stay on top of tension, shouldn't be an issue.

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On 12/2/2021 at 7:30 PM, isitafox said:

Absolutely love it! Can't wait to hear how they feel on the bike. Does make me wonder how they'd perform on a trials wheel as well? 

Thanks! I see no issue with trials use.

On 12/3/2021 at 12:00 AM, Swoofty said:

Great looking wheel! It looks more uniform than I thought it would. You'll need to re-tension 2 more times right? Or is this chord different from what BERD uses? Very excited to find out the results of all your hours labors.

Thanks Peter! Yeah I'm pleased with how neat it is. Having looked at close-ups of the Berd ones they seem to be a bit 'frayed' and scraggly all over. I'm using 2mm (though it measures at more like 2.3mm) SK99 D12 Max Dyneema, Berd use 1.8mm (which I assume is bought in as 1.5mm) DM20. The SK99 has a higher breaking load (for the same size) but the DM20 creeps less (for the same % of max breaking load). I'm hoping that overall my stuff will creep about the same or less because it's only being used at around 15-20% of max breaking load, whereas Berd's will be nearer 40-50%.

On 12/3/2021 at 8:48 AM, forteh said:

@Adam@TartyBikes is it a conscious design to not cross the spokes?  Presume the tension comes from stretching the rope rather than having the spokes contact and pull against one another?

It was. And I've had a rethink overnight, I think I will overlap them today. The wheel felt a bit weird when building up and I wasn't sure why, I think that might be the culprit.

On 12/3/2021 at 9:11 AM, Luke Rainbird said:

Contact would lead to additional abrasion too, presumably? As it stands there's some (unavoidable) contact with the loops at the hub end which won't really move around anyway, but otherwise mid-spoke (where any real movement will be) there should be minimal friction so provided you stay on top of tension, shouldn't be an issue.

But yes... that was my thinking. Though I don't think they will move much at that cross, and I figured if you rub two of the same thing together they will at least wear at the same rate (no crazy failures). Berd must have done some long-term testing so I'll cross them over today.

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Go for snowflake build!
Got to be fun playing cats cradle with your spokes :D

edit: Reckon you could get the threaded ends shorter on a later build to save more weight?  Could you alternatively look at having the tensioning at the hub end to reduce your rotational inertia?

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I wondered if at those angles and tensions that the friction would be enough. Might cause an issue with the cross pattern unless you go - in flange over flange and back through. That would probably stop any kind of slippage but the flange might not enjoy it.

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On 12/3/2021 at 10:36 AM, forteh said:

Go for snowflake build!
Got to be fun playing cats cradle with your spokes :D

edit: Reckon you could get the threaded ends shorter on a later build to save more weight?  Could you alternatively look at having the tensioning at the hub end to reduce your rotational inertia?

Ha! I did wonder about properly crossing the spokes over for a laugh, but thought I'd better play it as safe as I could for now...

Definitely could get the threaded bit shorter - I wanted to make sure there was definitely enough space to get a decent spoke key in. I've overdone it by at least 10mm though. Tensioning at the hub end... Not really sure how this would work. Getting anything in there to do twisty twisty would be tricky I think.

On 12/6/2021 at 5:34 AM, manuel said:

Looks fantastic!

anything stopping you using it as ‘pairs’ of spokes and halving your hub end splice time? Might create an odd load on the flange but should be ok? 

Cheers dude! I think the flange would be just fine in that circumstance - I mean it'll deal with radial spokes. I had a brief think about this right at the start of the prokect but couldn't find a way to make it behave like a 'normal' lacing pattern. I just tried again though and figured it out, so if you could create a 'lock' at the hub then it'd definitely work. Only issues it that this stuff is seriously slippery (static CoF of somewhere between 0.05 and 0.08 - ice is 0.05!). Perhaps one to ponder in future. Reducing build time in half would be a big plus though!

On 12/6/2021 at 10:26 AM, forteh said:

I think berd had tried that, seem to recall seeing it in the patent doc.  I think the main problem would be preventing the rope from slipping through the flange, knotting it causes a reduction in strength I think Adam said?

Yeah knotting is said to reduce strength by around 50% according to 'the internetz'.

On 12/6/2021 at 1:35 PM, manuel said:

I wondered if at those angles and tensions that the friction would be enough. Might cause an issue with the cross pattern unless you go - in flange over flange and back through. That would probably stop any kind of slippage but the flange might not enjoy it.

Wrapping the flange like that coud work... Maybe I'll have a little play tomorrow with an old hub and a bit of rope, see how / if it 'locks'. Sadly I've cut and spliced all the front 'spokes' now and don't have enough cord left to do a complete wheel, but maybe if there's a next time........

Thanks both for your ideas and input (Y)

 

In related news, the rear wheel now has a tyre on. I re-tensioned it twice before the tyre was fitted, and it dropped tension again (significantly) with the tyre inflated to 40psi (to stretch out the carcass). So I added a bit more and will see where it is when the tyre is dropped down to a more sensible pressure tomorrow. Holding out on building the front until I know it's gonna work.....

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Ha! I was aiming for extra compliance mainly (and to do something weird). The weight hasn't ended up that light compared with just buying light spokes :turned:

Front wheel completed...

20211207_120904.thumb.jpg.28d0fc16368e5a2c7a79c71c7e75859f.jpg

This is the alternative lacing I thought about. I think it will work. The rope kinda 'locks' itself against the flange quite nicely. I may remove two spokes from a normal wheel and put one of these in to test the theory out...

Benefits are: lighter due to less rope used (therefore cheaper too), faster to make, fewer splices so less bedding in / stretch (easier to make the spokes the right length), can make much shorter spokes (right down to mod size I should think).

20211207_092217.thumb.jpg.319f1d7e94dd025d15ae797d18340e38.jpg

20211207_092039.thumb.jpg.67243e6e8efd08b0dc64ad558a76f719.jpg

Bike is also complete and nearly ready for maiden voyage :dance:

ARSE.thumb.JPG.247ea560c365980e37830419c82a1441.JPG

Fell over while taking photos - first scratch, haha.

b6.thumb.JPG.6b4f28f3c9eed54213070fc1296fb1a4.JPG

b8.thumb.JPG.42517db1ac09f0652a6ac4762e6762b5.JPG

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8 minutes ago, Adam@TartyBikes said:

Ha! I was aiming for extra compliance mainly (and to do something weird). The weight hasn't ended up that light compared with just buying light spokes :turned:

Front wheel completed...

20211207_120904.thumb.jpg.28d0fc16368e5a2c7a79c71c7e75859f.jpg

This is the alternative lacing I thought about. I think it will work. The rope kinda 'locks' itself against the flange quite nicely. I may remove two spokes from a normal wheel and put one of these in to test the theory out...

Benefits are: lighter due to less rope used (therefore cheaper too), faster to make, fewer splices so less bedding in / stretch (easier to make the spokes the right length), can make much shorter spokes (right down to mod size I should think).

20211207_092217.thumb.jpg.319f1d7e94dd025d15ae797d18340e38.jpg

20211207_092039.thumb.jpg.67243e6e8efd08b0dc64ad558a76f719.jpg

Bike is also complete and nearly ready for maiden voyage :dance:

ARSE.thumb.JPG.247ea560c365980e37830419c82a1441.JPG

Fell over while taking photos - first scratch, haha.

b6.thumb.JPG.6b4f28f3c9eed54213070fc1296fb1a4.JPG

b8.thumb.JPG.42517db1ac09f0652a6ac4762e6762b5.JPG

Wow, work of art. You must be a time millionaire Adam.

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Haha thanks guys. I'm pleased with how its turned out. Can't wait for first proper ride!

And yeah, ti cranks Rowan. Had them a while, they're "life-ers", despite a date with the grinder last night to increase frame clearance :laugh:

 

Front spokes have dropped tension a bit today, will tighten them up shortly. Rears have settled down now.

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