mloywhite

I have a 32 spoke Powertap rear hub, and can get a really good price on a 24 hole rim that I really like. The guy who would build it for me suggests usiing all 16 drive side spokes, and every other one on the non-drive side. Does anyone have suggestions/comments as to whether this is a good idea, or the strongest way to build the wheel?

orangepaint

If you're already throwing down cash for a powertap, do it right and get a rim that matches. Reducing your spoke count will change DS and NDS spoke tension and could potentially make for a weaker wheel.

DiabloScott

That can't possibly work and your wheel builder is nuts (or possibly he didn't understand what you were asking).

You'd have to run some of the spokes from the drive side flange to the non-drive side of the rim and you'd only have 8 spokes left from the other flange (every 4th, not every other). You'd have dozens of other problems too but that one's the worst.

Seriously, you've got a megabuck hub, get the right rim for it.

dabac

I wouldn't do that for a paying customer, but as a wheel for myself it's actually not that bad. You'd need to run your powertap hub through a good spoke calculator to see what the tensions would look like though - see what % of DS tension the NDS ends up at.

I've got a hub that would give 55% DS tension on the NDS for a traditional lace. Using only every 2nd NDS spoke would make for a very balanced wheel in that configuration with only a 10% mismatch.

YMMV though, as it's been a bit of a trend to move the NDS flange inboard in order to compensate for the dish, this might make the every 2nd approach overcompensate instead.

If your setup would give the more average distribution of roughly 2/3 of DS tension on NDS then you haven't really won anything.

Rim drilling might complicate things. If the rim has a pronounced offset drill you get a bit of a nasty bend trying to get a spoke aimed at the left flange to align properly with the right flange.

Another option is to leave every 4th hole empty on both sides, and lace the wheel in a crow's foot pattern of 3 spokes to the group. Then if powertap is sized roughly similar to other hubs you'd be able to use 2.0-1.8-2.0mm for DS spokes and 2.0-1.5-2.0mm NDS and get a decently even tensioned wheel.

All of this assuming you're light enough to be riding a 24H rim to begin with of course...

eddy m

Actually, 16 and 8 spokes is called triplet lacing, and it makes a stronger wheel than 12 and 12, but if you break one of the 8 spokes the wheel becomes unusable pretty quickly. You could build it 12 and 12, but you need to think about whether you are comfortable with a 24 spoke wheel. I weigh 195 and I wouldn't ride a 24 spoke rear wheel unless it were laced 8 and 16. If you build it symmetrically, you should use an ordinary cross 2 pattern and adjust the length of the spoke to make it work.
At my weight, I would buy a 32 hole rim, especially if I intended to ride the wheel all the time.

em

waterrockets 

1st off, this is a BRILLIANT lacing pattern. This is essentially what Fulcrum does with all their wheels (1/2 spoke NDS). It will be stronger than a traditionally laced 24h wheel, and I'd wager it's right up with a 28h wheel because of the benefits of having equal spoke tensions on both sides. I really really really like this lacing pattern.

There's a problem with a PowerTap though: the torque applied to the cassette transfers to the NDS flange first, since the "torque tube" runs between the freehub body and the hub. So the right flange is essentially a bushing that just keeps the DS of the axle radially centered in the hub, and allows it to twist inside it. Once the torque reaches the NDS side of the hub, the aluminum crossbars in the shell and the bonded CF windows do the torque transfer back to the DS side of the hub.

So, you need to make sure that your lacing pattern allows most of the torque to be applied on the NDS flange, which means you have to have a pretty tangential spoke angle on that side. Saris told me on the phone that an asymmetric lacing patterns can cause PowerTap hubs to "explode." So they don't even like the 1x DS and 2x NDS lacing patterns. I've built a 1x/3x wheel, and I know Ligero and several other builders do 1x/2x and 1x/2x patterns as well (always with more crossings on the NDS).

I think Saris would COMPLETELY poo-poo this idea, but if you laced the NDS 1x with 8 spokes, it should be able to apply full torque just fine. There are plenty of 16 spoke rear wheels out there that have only 8 spokes per side (Rolf even has some with 12 spokes). So, there's no question that 8 spokes can handle the torque.

Note also that you don't want thinner NDS spokes as you might do on a traditional wheel, since they will be at the same tension (or a tiny bit higher) as the DS spokes.

Still, something about it scares me with a PowerTap. It's just such an expensive hub. It would be cool if I could get a dead SL from PowerTap to try it out though.

dabac

Why wouldn't it?

Yeah, that's the catch. If spoke holes are too angled he'll get a bit of a bend at the nipple.
Still, since we don't know which rim hell be using we don't know if it'll be an issue or not. I've built wheels in lateral cross deliberately before. Don't know how much good it's actually doing me, but they remain fully serviceable w/o any hassle anyhow.

I'm not saying it's a great idea, but I'm curious about why you think it'd be impossible.

The DS side gets laced at the hub just like a regular 32H, then the rim gets hooked up with every 3rd hole empty(some adjustment of spoke length may be required.). The NDS gets laced as if it were a 16H hub.
3X might be awkward on the relatively high flange, but due to that 2X shouldn't be a problem either.
Trueing becomes a little special, with spokes needed to be dealt with more in groups and less individually.

eddy m

[QUOTE=waterrockets;7116037]1st off, this is a BRILLIANT lacing pattern. This is essentially what Fulcrum does with all their wheels (1/2 spoke NDS). It will be stronger than a traditionally laced 24h wheel, and I'd wager it's right up with a 28h wheel because of the benefits of having equal spoke tensions on both sides. I really really really like this lacing pattern.

There's a problem with a PowerTap though: the torque applied to the cassette transfers to the NDS flange first, since the "torque tube" runs between the freehub body and the hub. So the right flange is essentially a bushing that just keeps the DS of the axle radially centered in the hub, and allows it to twist inside it. Once the torque reaches the NDS side of the hub, the aluminum crossbars in the shell and the bonded CF windows do the torque transfer back to the DS side of the hub.

So, you need to make sure that your lacing pattern allows most of the torque to be applied on the NDS flange, which means you have to have a pretty tangential spoke angle on that side. Saris told me on the phone that an asymmetric lacing patterns can cause PowerTap hubs to "explode." So they don't even like the 1x DS and 2x NDS lacing patterns. I've built a 1x/3x wheel, and I know Ligero and several other builders do 1x/2x and 1x/2x patterns as well (always with more crossings on the NDS).

I think Saris would COMPLETELY poo-poo this idea, but if you laced the NDS 1x with 8 spokes, it should be able to apply full torque just fine. There are plenty of 16 spoke rear wheels out there that have only 8 spokes per side (Rolf even has some with 12 spokes). So, there's no question that 8 spokes can handle the torque.

Note also that you don't want thinner NDS spokes as you might do on a traditional wheel, since they will be at the same tension (or a tiny bit higher) as the DS spokes.

Still, something about it scares me with a PowerTap. It's just such an expensive hub. It would be cool if I could get a dead SL from PowerTap to try it out though

dvancleve

Hi there. I was Googling for info on how to lace a wheel like this, just a regular hub (drilled 8/16 though) and this thread is about all I found. I would be using a Gipiemme/Cannondale Tecno hub from eBay and a Sun Venus rim. I use spocalc and I am not sure how to get accurate spoke lengths for lacing like this. If the non-drive side is radial, that is easy but if it is 1x then I'm not sure about it either. I assume that it is more complicated than using the 32 spoke lengths for the drive side and 16 spoke lengths for the non-drive side...

Thanks, Doug

P.S. I would have tried a PM with more details, but I can't send them...

Ex Pres 

You need [I think] 50 posts for a PM. And you're right, it requires a little more than the basic spocalc to lace [essentially] a 16 hole hub (the NDS) to a 24 hole rim. I could sit down and draw out the angles and functions to be used, but I can't relay them off the top of my head. Hopefully waterrockets shows up here, since he's laced this pattern before.

AEO

that Gipiemme/Cannondale Tecno hub is supposed to be used with a Gipiemme/Cannondale Tecno rim.
I've seen the rim, before and it was similar to campy G3 style drillings, which is set of 3, wide gap, repeat.
Now, I haven't looked at the hub closely, but I would assume it's not too different to a 32h hub.
This page covers how to calculate mismatched hubs and rims. https://www.sheldonbrown.com/rinard/36-24.htm

Now, if the hub is drilled exactly like a 32h hub, which will have holes that are (360/16) 22.5 degrees apart, and (360/32) 11.25 degrees offset from the opposite side, then I've already calculated the cross length needed for that. Which is 2.38x for a 3 cross pattern on the drive side. The non-drive side spoke lengths can be radial or 1x using 16h spacing, or 2x with 32h. You should notice that 16h 1x is the same length as 32h 2x.

You can use decimal cross lengths in the spocalc you can get off of the sheldon website. https://www.sheldonbrown.com/rinard/spocalc.htm

But, if the hub is drilled differently, where in the spoke hole offset on opposite sides isn't 11.25 deg, then you're going to have to pull out a calculator or experiment with a few different spoke lengths.

dvancleve

Update: I am not going to get the Gipiemme hub. I was told it is probably about Sora quality, so kinda cheap and heavy. Also, despite listing a "Best Offer" option, the seller rejected all of my offers including one that was with a buck or so of the BIN price so I decided to bag that idea. If I try it, I will be using an older White Ind. 32 spoke hub, which will make for a completely matching wheelset as I already have a White/Venus 24 spoke front wheel. It appears that a 3x right side triplett lacing is about the same as 3x/30 output from spocalc, 2x right side is about the same as 2x/30 and 1x for the left side is about like 1x/28. I got that info from a post I found by Troy of Ligero, but I am trying to confirm that the 3x/16 side should use the 3x/30 spoke length...

Thanks, Doug

pressed001

Hey gents, quick question regarding this topic:

I have DA 7700 32 hole hubset and have just purchased some 32 hole H+son rims. I weigh only 150 and although I want the wheels to be robust, 32 hole is overkill. For example: I have built a 24 spoke super-light wheelset for my cross country mtb and have never had an issue.

Question: it sounds simple to build up a 1/2 laced rear wheel. I lace 2 cross all 16 DS spokes and then just 8 either radial or 1 cross for NDS. But, would that work for a 32 hole rim? I understand that some of the holes would be left open. Are there issues there that would make this a no-go?

Building it with 32 spokes would also be zero problem but I think the 24 would hold up just fine for me and would look better, minus the empty spokes holes.

ksryder

Holy 10-year-old thread, batman!

Not a wheelbuilder but there was a similar question recently (I can't find it now) and the general consensus was that the rim would be weaker without all the spokes. I don't know and don't care about the science, because how much weight are you saving with those 8 missing spokes? I'd imagine you could get the same benefit from a little extra time in the bathroom on raceday morning.

pressed001

lol

I am more interested in form and function than weight savings. I think it will look a lot better with 24 and I should not lose any functionality. Question is, is it possible and yeah, would it even work well.

Edit: it is called triplet lacing where 16 DS spokes are all laced and only 8 NDS are laced. I would like to pull this off but don't like the idea of having open spoke holes left unused on the rim. The H+Son SL42 is surely stiff enough for this lacing type.

Mr IGH

I have done this with a 32H hub and rim. I wanted to match my 24H DT wheelset with a dyno hub and I had a smaller 1.5W hub in-hand. The bike has disc brakes so I laced the disc side 3x and the non-disc side radial. I used a DT R460 rim with 16 spokes on the disc side, 8 on the non-disc, aero/bladed. Works great, I have ~1000 miles on it without any issues. Handles just fine. I got the idea from my Mavic Askium rear wheel which is laced in a similar manner and has performed flawlessly for over 10Kmikes with my >230lbs on it.

I got a kick out of the thread ksryder referenced where the internet road-runner physicists predicted disaster on this configuration. Wasn't worth the time to try and straighten them out. An earth science background isn't not going to get them through simple statics....

fietsbob

36 hole hub, 24 spoke rim works.. as on my Bike Friday , 16" 349 rim. IGH rear

You big wheels just buy a 32 hole rim, why be cheap ? And its your rear wheel your weight majority is on the rear wheel..

IMO, the power meter things are tech fluff, for a transportation cyclist.

....................................................................

buy a 24 hole front hub if you love the look of the 24 hole rim..

32 hole rear wheel hub/rim 24 spoke front.. hub/rim .. Boom.. ! Done





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Kontact 

This is normally done on a 32 because 24 and 32 are both divisible by 8. How is it done on a 36? 18 on the drive side and 6 on the NDS?

pressed001

Can I ask you guys for a quick double check?

Rims: H+Son SL42 32h ERD 557

Hubs: DA 7700 32h
front:
flange diameter l/r: 38
center to left: 37
center to right: 37
spoke hole dia: 2.4
24 spokes, radial: 260.9

rear:
flange diameter l/r: 44
center to left: 36.9
center to right: 21.1
spoke hole dia: 2.4
24 spokes, Triplet lacing:
DS 16 3x: 270.5
NDS 8 1x: 264.8


This was a little tricky as with SpokeCalc I had to set the rear wheel to 32 3x for the DS 16, and then to 16 1x for the NDS 8.

fietsbob

On my 24 hole rim , IGH the 2 cross is at a tangent, angle, it passes by the skipped hole and the opposite spoke on the other side of the flange , 1st cross,
symmetrical for both sides..

NB: not everyone has freehubs..





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Kontact 

Okay - so each side has two spokes together, then skips one, then two together. Got it.

DiabloScott

Check this out:
Size of the hub flange is exaggerated to show the spoke pattern... I don't think the first cross would be so close to a real flange. And the large circles are the empty holes on the NDS.

CliffordK

Campagnolo essentially does that.

Lacing in triplets. Right/Left/Right.... (Space)... Right/Left/Right. With the right side crossed, and the left side radial.

I can't say whether it is any better to do it that way vs evenly distributing the spokes around the rim. But, evenly distributed, one gets two spokes close together pulling in the same direction. With the space, the two right spokes are mostly offset by the single left spoke.

I picked up an odd wheel from the bike co-op recently. Laced pairwise... right-right/left-left/right-right.... etc. The wheel has a horrible hop so something obviously went wrong sometime. I have to decide whether I want to try to true it as is, or relace.

Kontact 

You really didn't need to do all that. You just recreated the same lacing as the Fulcrum wheels. They are only 24 hole hubs because the other eight holes on the NDS weren't drilled.

Kontact 

Skipping spoke holes on the rim is a bad idea. Rims have very little strength of their own, and having gap with a hole in it is just giving the rim a chance to collapse.

You can get away with it more with a fat tire, but still, bad idea.