Dynamo Disc Lacing Alternative: All NDS Spoke Heads Out?
Justin Hughes
The wheel (32h 650b, 567 ERD) is currently laced traditional 3x and is perfectly centered. The spoke interference is slight but it is there. If all the rotor side spokes were head out (elbows in) the spokes would sufficiently clear the caliper. I realize different lacing is not ideal and that front disc hubs are under specific stresses. With that:
- Could I lace the wheel 2x or 3x with the rotor side spoke heads out?
- Would using CX-Rays help the spokes cross one another better and make a stronger wheel than the current Sapim Race?
- Would it help to use spoke washers?
- Should the DS be laced the same as NDS?
Thanks!
satanas
1. x2 or x3 on the RHS, and radial on the LHS with heads out, or
2. x2/x3 on *both* sides but with all the LHS spokes having the heads on the outside of the flange?
If 1) that's the opposite of normal but a similar strategy works on rear wheels so it should be possible.
If 2) I'd think the wheel would be very difficult to lace, though less so with thinner spokes. I'm not keen on the idea but can't think of a terrible problem right now; I suspect there might be one though.
Depending on what spokes you have now and how much room you need to make it might be that CX-Rays could do the trick. If current spokes are DT Comps, the centres are 1.8mm, whereas the centres for CX-Rays are 0.9mm, so that's 0.9mm saved at the spoke crossing with no other changes.
I can't see how washers are going to help unless the elbows are too long or the flanges are too thin. They're certainly not thick enough to enable the spokes to pass each other if all laced from the same side of the flange and crossed.
What exactly touches, and where, and what calipers do you have?
Later,
Stephen
Justin Hughes
Andrew
And Stephen asks the question of probably general interest about which caliper. I also will be building with the very similar PD-8X-M hopefully sooner than later.
Given that there is space for washers at all, I'd have thought that they take up whatever small outwards movement might have been possible with the length of the spoke elbow.
I suggested an asymmetrical rim above but deleted the post because the gain would be so small for so much cost ( though sometimes that's not an impediment in the cycling space!)
Stephen Poole
On 7 May 2017 12:41 am, "Justin Hughes" <justin...@me.com> wrote:
>
> Stephen,
> I am suggesting #2, to lace 2x or 3x (even 1x) but with all the LHS spokes head out. I'm not against #1, but it stands to reason that crossing any number of times helps in this situation (torsion).
IIRC, the current Dura-Ace rear disc wheels are crossed on the RHS, and have half as many spokes, laced radially, on the LHS. As long as the hub shell is in one piece and stiff enough it's only necessary for one side of the wheel to be crossed to transmit torsional load, whether driving or braking. It would be much easier to lace the LHS radially, heads out, if that would give enough clearance.
> Currently laced with Sapim Race so 1.8mm at point of contact. The spokes barely hit, but this cannot stand. I can try to take a video later. If you spin the wheel in the stand it will make several revolutions before stopping all the while sounding like a wind chime.
Are the spokes hitting the caliper where they're crossed, i.e., at the intersection? If yes, the spokes protrude 1.8mm each side from where they cross, i.e., 1.8mm towards the outside where the disc is (and inside too). CX-Rays are only 0.9mm thick sideways, so can only protrude half as far - you should gain 0.9mm.
> My thought of washers was only that it would might ease the flange interface since the spokes are most vulnerable at the bend.
If they were laced as suggested I doubt things would change much at the flange; the bend at the elbow should be adjusted to suit as per normal practice. There will be more lateral bend(s) elsewhere, but whether this will matter...
> Head in/elbow out LHS spokes hit the lower bout of the disc caliper. Currently have SRAM Red hydraulic post mount caliper on ISO tab. Interference was present with TRP Hy/Rd. I moved to Red hoping I wouldn't have this issue and at this point I am not going to change brakes and levers. I will take my chances with a alternatively laced wheel first.
I've heard this overlap is a problem with Spyres and dyno hubs too, which is what I'm likely to end up with. :-(
Later,
Stephen
satanas
Both the smaller flange diameter and the offset ought to generate (sorry!) a bit more clearance than the SP hub, all else being equal. I was planning on using CX-Rays in any case, but the smaller hub shell might just be a good reason to stick with Schmidt and a matching 12mm fork.
Later,
Stephen (who thinks that Fixation fork is looking better all the time)
Justin Hughes
Justin Hughes
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Andrew
https://forum.cyclinguk.org/viewtopic.php?t=103406
And my earlier comment about only getting 0.45mm from the use of bladed spokes was wrong - Stephen analyzed it best in commenting on the spoke crossing. By using bladed spokes you almost save 0.45mm three times - once each on the two faces that touch when crossing, and once on the outer face of the outer spoke at that point. By the way, DT Swiss Aero Comp are roughly a dollar each cheaper than CX-Rays where I buy spokes online - I don't know if that is the case everywhere.
njh...@gmail.com
Here's a photo of the clearance between the spokes laced to my PD-8X hub and the disc caliper - there is only a small fraction of a millimetre clearance but it does just clear. The hub is 32h x3 spoked to a DT Swiss XM401 rim with 565 ERD and the caliper is a SRAM Force flat mount - 160mm rotors. Because of the crossing of the spokes, it's actually the spokes with heads outwards, exiting from the inside of the hub flange, that come closest to the caliper. One thing you can't do with the Shutter Precision hub is lace the rotor side radial and rely on on the braking torque being transmitted by the crossed spokes on the other side of the hub, as the hub shell is comprised of two separate sides that are pressed together during assembly of the hub.
Stephen Poole
This all sounds like a nightmare! :-(
Re the SON 15mm hub: If radial spokes are 251mm, and the flange moves in 2.5mm then the clearance ought to increase by roughly (251-80)/251*2.5, where 80 is the rotor diameter and more or less the average of the radii of the rotor mounting bolts; say 1.7mm +/-. (I don't have anything with post mount discs to measure, only flat mount.) However, increasing the PCD will reduce clearance slightly too.
It seems like the biggest contributor to the problem is the increase in flange diameter from a normal front hub to a dynamo hub, but some of the non-dyno hubs aren't all that small. On my Sequoia the pcd is 57mm, the outside of the flange is 28mm from the inside dropout face and there is 3mm clearance from the 2mm spokes to the Shimano flat mount hydro caliper; the rim has centred drilling. The only thing about the wheel that's really helping clearance is the rotor side flange position, which is a bit more inboard than SP's 25mm, however I suspect the caliper is lower profile too; no idea if flat mount does anything either way, sorry.
It sounds though that you've already been through a number of iterations, and if I were you I'd be very reluctant to change things randomly in hopes of a fix.
The UK forum Andrew linked to has some useful stuff, and both brucey and gattonero are very knowledgable; brucey in particular appears to know just about everything(!).
Out of curiosity, what have you tried so far, and can you rank them in order, clearance-wise, please? This would be helpful to others further down the track. Also, what brake levers are you using? (This will affect caliper compatibility if they're hydro.)
Maybe cantis aren't so bad after all!
Thanks, and best of luck with resolving things,
Stephen
Stephen Poole
Just read Nick's response - radial spoking on the disc side is definitely out.
Seems like the things that might help are:
1. Elliptical spokes (thinner sideways)
2. Space rotor and caliper outwards
3. Maybe don't interlace the rotor side spokes(?). If the spokes go directly from the flange to the rim without interlacing this should reduce the "bulge" near where they cross (if that's where the problem lies), however it might reduce wheel stability a tad. Since radially spoked wheels survive okay this shouldn't be a big deal, but please don't sue me. ;-)
The Shimano hydro calipers definitely appear to be lower profile on the inside than most, apparently for a good reason. This is a bit of a bummer for me as I was planning on avoiding hydro calipers and brifters to make things simpler - sigh. Mumble, mumble %#!$=/ brakes!
To quote Buffalo Springfield:
"It's time we stop
Hey, what's that sound?
Everybody look - what's going down?"
Later,
Stephen
Jeff Bertolet
On Saturday, May 6, 2017 at 11:37:42 AM UTC-4, Justin Hughes wrote:
Thanks, Stephen. FWIW, I did have this issue with Spyres and the QR 6 bolt version of the SP dynamo. I resolved it on that bike with a 180mm rotor.Interesting on the Dura Ace hubs. I tried to find some pics and it looks like those are straight pull spoke flanges with the NDS spikes crossing on those that I saw. That would be a good design for these dynamos at least in regard to this clearance issue.Yes, point taken on difficulty lacing. I calculated the spoke length for radial lacing on this wheel and if I or my LBS has 16 251mm spokes I may attempt to rebuild it this afternoon.Here are a couple pics showing that the caliper actually hits at the lower bout, but is almost as close to hitting the knuckle of the hydraulic banjo.
Stephen Poole
On 7 May 2017 11:47 am, "Jeff Bertolet" <jbf...@gmail.com> wrote:
>
> Can't tell exactly from the pics, but it looks like the rotor is very close to the fork leg as well. Is that true?
>
> Some carbon fork have a flat indent on the leg for rotor clearance.
As a data point, the Sequoia forks are basically straight on the inwards face (albeit with a ~3mm recess for the hub) as is the Rodeo Labs Spork. The Spork has no rotor recess, but is narrower both near the crown and thinner low on the legs; they're saying it's "60mm at 650b" while the Sequoia fork is ~75mm at 320mm from the hub centre. In practice both are probably close in internal width near the caliper.
> This seems like an issue primarily with flat mount calipers, or just hydro calipers on small rotors?
Seems like the issue is with dyno hubs/large flange hubs, on a variety of forks. Most of the problems I've read about have been with post mounts, but maybe that's just because more of those are out there than flat mounts. It's hard to say as there aren't really any forks which exist in two versions; FWIW, flat mount forks can be adapted to accept post mount calipers but not vice versa.
With flat mounts one is limited to 140 or 160mm rotors, so fitting a 180+ rotor to gain spoke clearance isn't an option.
I would think things are better with Shimano hydro calipers and worse with many bulkier calipers, i.e., Spyre, etc.
I'm at the start of ordering a frame right now, so would really like to know what, if anything, works reliably; a dynamo hub is essential. I guess cantis are my fallback position, and I am *certain* they can be made to work!
Later,
Stephen
Justin Hughes
Stephen Poole
On 7 May 2017 12:59 pm, "Justin Hughes" <justin...@me.com> wrote:
>
> In this instance I don't wish to move the rotor closer to the fork blade than it already is. I did use the DT Swiss centerlock to 6 bolt adapter to mount a 180mm and the rotor rubbed the fork so slightly as to discolor the powdercoat. This is too close for comfort. The profile of the fork blade was not indented/modified. I don't think it's the best idea to shim the rotor in with this particular setup. Besides that, my intent all along was to use 160F/140R rotors.
If the only thing stopping you from using a 180mm rotor is slight rubbing, then indenting the fork blade very slightly is likely to fix that, assuming it's steel; if done carefully this shouldn't damage the paint. That doesn't help with using 160/140 rotors, my plan also.
> Stephen can you explain your point #3? I've only built a few dozen wheels and the vast majority using the steps laid out starting on page 86 of The Bicycle Wheel. I don't believe any of the head-in spokes on my wheel are interlaced. They are the outside each spoke they cross.
Interlacing is where the spokes from the two sides of the hub flange go over and under each other. With radial spokes they don't touch each other at all, and with 1x they cannot be interlaced, however with 2x or more if you follow a spoke from one side of the flange it will normally cross *over* a spoke (or spokes if 3x or more) from the other side of the flange, and then *under one*, or vice versa. At the outermost crossing the two spokes "swap sides" and press against each other. This makes the intersection a bit bulkier but helps prevent total loss of tension when hitting bumps, sometimes an issue with LHS radial spokes on heavily dished rear wheels.
Almost all wheels are interlaced this way. Usually if they're not it's because of an error by a novice builder, or on a really crappy, cheap bike from a department store. Interlacing costs nothing except a little time, and usually gives a bit of insurance/load sharing. In this case though it might be worth *not* interlacing the rotor side spokes as that would save a little bulk at the outermost crossing - I can't tell from the pix if this is where the problem is though, do it might achieve nothing.
> We can say with relative certainty that with 3x DS and head-out radial lacing on the NDS (rotor) braking forces will brake/separate the hub shell?
No idea, but not worth the risk IMHO unless other options are exhausted.
> How about the idea of keeping the DS as is with the 3x Sapim Race spokes, but lacing the NDS 1x with CX-Rays spoke head-out? Head-out would give me the clearance needed and using the elliptical spokes 1x lacing looks like it would put the spoke crossing at the flat part of the spoke making for a much better cross than one closer to the J-bend.
With CX-Rays the crossing would be on the flat part of the spoke whatever the pattern, assuming heads aren't all on one side of the flange; the butted section is very short. 1x LHS/3x RHS would mean the RHS spokes would be a lot torsionally stiffer than the LHS, which could mean some torque gets transmitted across the hub shell; wind-up would be limited but I've no idea what it might take to damage the hub. If it was me I'd try really hard to stick with 3x on the rotor side; less on the other side shouldn't be an issue, but more might be. I'm suspicious about tangential (3x) spoking with all the heads on one side of the flange, but it might work; I have a bad feeling about it though, and as you point out the 2mm butts would cross, causing some spoke deformation. If you try this, please let us know if it works.
> FWIW, the overall size of the caliper between the rotor and the hub looks to be the same on both the Hy/Rd and SRAM Red when comparing the flat mount version to the post mount version of each model.
Thanks, useful info.
> Wrote Stephen: "Out of curiosity, what have you tried so far, and can you rank them in order, clearance-wise, please? This would be helpful to others further down the track. Also, what brake levers are you using? (This will affect caliper compatibility if they're hydro.)
>
> Red 22 Hydro R levers.
So Shimano and Magura calipers are out as they use incompatible fluid. I wonder if there might be more compact calipers which use DOT fluid - Hope perhaps? (Clutching at straws here.)
> I don't even recall now if the rotor cleared the spokes (I know, that's terrible). I have tried Hy/Rd calipers and the front post mount caliper hit the spokes with 160mm rotor. I have not yet tried a different 160mm rotor be it centerlock or 6 bolt. I may rob one from my MTB and see if it's any different.
I would hope and expect that different rotors should be very, very close to the same laterally, but who knows. Thinking aloud, I wonder if perhaps a thinner rotor might enable the caliper to be a tiny bit more outboard? I'm thinking Shimano IceTech (thick) versus something else, but maybe they're all the same nominal thickness at the braking surface; the IceTech fins or centres foul some non-Shimano calipers, but that's another problem.
> Sincere thanks for everyone's thoughts on this. It's disappointing not to have this bike built up and on the road. I'm seriously considering buying a complete non-dynamo wheelset Monday as a second set just to get this bike on the road.
^ Sounds like overkill - surely you'd only need a front?
If people could post combos that actually work that would also be appreciated! Please list caliper model and style (PM or flat mount), hub model and drilling, 6 bolt or Centerlock, spoke type and lacing pattern, rim model/size/offset if any, rotor model and diameter, fork used, etc.
So far it looks like either Shimano hydros or cantis for the win...
Later,
Stephen
Andrew
Justin Hughes
Stephen Poole
On 7 May 2017 3:03 pm, "Justin Hughes" <justin...@me.com> wrote:
>
> The wheels on this bike and others in my basement built by me do not have the spokes touch or interlace at the third crossing. Apparently, this was an oversight on my part that I've let slip on the last several builds. Until now this hasn't presented a problem. But, here it has. You are saying the opposite, Stephen, but wouldn't crossing that head-in/elbow-out spoke under the adjacent spoke give me more clearance? I will detension and change this and see if it is enough.
What I was trying to say(!) is that where the spokes are interlaced there is effectively a "bulge," though things may be tighter elsewhere too. On rear wheels this "bulge" is often in exactly the right place to foul the derailleur cage, or the top jockey wheel bolt, e.g. on Dura-Ace 7400 series rear derailleurs. In that case, thinner drive side spokes (or a larger cassette) often make the difference between tinkling in bottom gear and silence.
With your front wheel I don't know just exactly how far along the spoke things are touching, so can't really say what might help regarding interlacing. I'd assumed the wheel was built as per normal, but if not then changing things might help. Since you can see what's going pn you'll be better able to judge that than me. :-)
> I did just use a TRP 160mm 6-bolt rotor on the hub using the DT Swiss adapter and the spokes still rubbed. I then put 1mm thick washers under the rotor and this caused the rotor to just rub the fork barely. This was just enough for the caliper to clear the spokes.
If it's a steel fork a small indent plus a spacer should fix things then; I wouldn't hesitate to do this if it was my fork, but I have some work experience with this and would suggest "discretion is the better part of valour" otherwise.
> Andrew, the initial plan for this build was to use the Motoko calipers with SRAM mechanical levers, but the rear post mount caliper hit the seat stay with the Shimano 140mm flat-mount-to-post-mount adapter. I probably could have filed enough off of the Motoko caliper base, but instead I ordered Hy/Rd calipers. Then the front wheel spoke/caliper interference.
Thanks. So what the above boils down to is to stick with a flat mount caliper if using a 140mm rear rotor.
If I was you I'd look at where the spokes touch the caliper, relace the wheel if that might help, and indent the fork blade if it won't, or doesn't do enough.
I'm now feeling more hopeful that my hypothetical solution might work: Fyxation Sparta fork, 28° SONdelux 12 hub, x2 (or x3?) CX-Ray spokes, Crest Mark 3 rim, Dura-Ace 9100 STI & 160/140 rotors and TBC flat mount calipers. Plan A was to use Spyres, but it seems these are bulky, as are HY-RDs. The only way I'd ever see the JT/Motokos is to order some so not a good option re spares.
If things got too messy I suppose Dura-Ace calipers and hydro levers would work, but at greater cost and complexity - and then there's the Di2 option; not that any of these things are available yet. :-P
Later,
Stephen
Andrew
There are some good pics of the Motokos in a recent Cyclingtips review. Maybe its the angle, but it looks like heaps of clearance.
And would you ever really need parts? For something like this, you'd change the oil a couple of times in 10 years (maybe) and if it failed after that you'd get a replacement yourself without much sense of regret. Pads are likely some standard or another.
Andrew
On Sunday, May 7, 2017 at 5:07:20 PM UTC+10, satanas wrote:
I'm now feeling more hopeful that my hypothetical solution might work: Fyxation Sparta fork, 28° SONdelux 12 hub, x2 (or x3?) CX-Ray spokes, Crest Mark 3 rim, Dura-Ace 9100 STI & 160/140 rotors and TBC flat mount calipers. Plan A was to use Spyres, but it seems these are bulky, as are HY-RDs. The only way I'd ever see the JT/Motokos is to order some so not a good option re spares.
Later,
Stephen
njh...@gmail.com
Justin Hughes
Jeff Bertolet
Stephen Poole
I'd think a steep, standing climb at low speed in a relatively high gear ought to be a good test; I've occasionally had rub on the (rim) brake pads under these conditions with minimally-spoked and tensioned front wheels in the past.
I sincerely hope all goes well for Justin - it sounds like a long, expensive and painful business to me.
Andrew
Seems like the things that might help are:
2. Space rotor and caliper outwards
Stephen Poole
Andrew, please report back on the CX calipers once you've used them! Hayes hadn't occurred to me as I had traumatic experiences with servicing their early hydro MTB brakes; they seemed to need bleeding after every ride, and I vowed to avoid them.