Weight Weenies

I apologize if this has already been addressed, but I skimmed this thread and didn't see it.

I'm curious what people generally think about radial lacing on the front wheel. There are several hub manufacturers that recommend against it as it puts a large outward force on the hub flanges. The more spokes, the thicker the spokes, and the higher the spoke tension, the more force.

So my question is:
Radially laced front wheels look cool, and they are ever-so-slightly lighter due to the shorter spokes, but are there any other advantages/disadvantages that anyone cares to comment on? My feeling is that we mostly do it for aesthetic reasons, but I'd love to hear what other have to say.

The concern with using radial on the rear is the torsion (I think that is the correct word here) from pedaling. Since there is no torsion in the front wheel, except in the case of disc brakes, that reason is discarded.

Then there comes the question of the stresses on the hub flange. Yes, the stresses are higher. The thinner the space between spoke holes on the hub flange, the thinner the flange itself, or the higher the tension, the more likely the flange will fail. So, a standard flanged hub will me more likely to fail under raidial lacing than crossed (as the crosses will ideally pull tangentally, rather than radially).

However, this does not mean that lacing spokes radially is a bad idea. Simply that radial lacing a flanged hub may cause damage, esspescially on lower quality materials. The advantage of radial lacing is that the spokes pull perpendicular to the rim, which distributes the load more evenly on the rim. So my recomendation is to use straight pull hubs and spokes (which we should be doing anyway, but that is for another thread). Inveitably, someone will say that the straight pull spokes will not be properly supported by an aluminum hub. I think that tune solved that problem pretty well by using carbon fiber around the spoke holes to deal with the tension.

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jgspin wrote:I don't race. I weigh 127 lbs. I currently have a wired powertap pro with all aluminum shell (no Carbon window) laced with 32 spokes. Without skewers it weighs 1379 g. Would it be ok to lace my 32h powertap to my rim which is 16 h Alta aluminum clincher about 27 mm deep. If it is ok, what spokes should I use and how should I lace it? If it's not advisable then what weight savings would I get if I lace it to a 24 hole aluminum clincher such as Kinlin XR-200? Thank you.

Even though that is a fairly stiff rim and you are light, 16h would be pushing things IMO. You could lace the rear triplet style to a 24h rim... but not a XR200... an XR270 or XR300 would be ok.

Probably the best choice would be a crows-foot lacing with a 24h rim, and you could then use a XR200 if you wished. I haven't actually done this... but it seems like it should work, skipping every 4th hole in the hub. If you have decent derailleur clearance you can probably lace both sides all heads-in for the best lateral stiffness. Use CX-Rays or Aerolites for the best aero and lowest weight.

toutenhoofd wrote:Radially laced front wheels look cool, and they are ever-so-slightly lighter due to the shorter spokes, but are there any other advantages/disadvantages that anyone cares to comment on? My feeling is that we mostly do it for aesthetic reasons, but I'd love to hear what other have to say.

Better aerodynamics... with cross-lacing the area around the hub is pretty messy. Also, if you can lace the hub heads-in radial this can give better lateral stiffness. No huge differences though.

Could one of you experience wheelbuilders tell us a little about cold setting spokes? How important is it? How is it best done, what to avoid, etc? I've googled a bit, but found little.

Afa those of you having difficulty getting Unior tools are concerned, I am an American living in Germany, and have a checking account in the States, so I could pick up the tools over here and mail them to you, while you could pay me in dollars. I don't know the prices yet.

Is there a way to convert my ts-2 truing stand to using gauges? I don't build a lot of wheels maybe 4-5 for me and my friends a year but I like the idea. It looks a lot more accurate. I just like tools I guess.

Dial guages can have magnetic bases or just clamp on and you can get rose-jointed extensions. Waste of time if you ask me.

I'm no expert on 'cold-setting' but you need to set the bend on the spoke so you get as clean a line from flange to rim as poss. Simple as that. Do it before you reach max tension for a better result. Make sure this applies to each 'cross' to reduce the spring in each spoke, which may result in the wheel losing tension unevenly in use.

Dont overdo it - straight spokes with a crisp bend and cross are what you are looking for.

toutenhoofd wrote:Radially laced front wheels look cool, and they are ever-so-slightly lighter due to the shorter spokes, but are there any other advantages/disadvantages that anyone cares to comment on? My feeling is that we mostly do it for aesthetic reasons, but I'd love to hear what other have to say.

radial spokes are easier to clean! If a hub has been designed for radial spokes, then you should have no problems. The grams saved by radial lacing over crossed lacing can probably be counted on the fingers of one hand.

BruceCarnevale wrote:Could one of you experience wheelbuilders tell us a little about cold setting spokes?

You want the spoke to take straight lines from the hub to the rim with minimal or no bending loads. This involves tweaking the spoke at the J, the cross, and the nipple. Don't over do it.

The nipple area is most important on rims with center drilling. Often if nothing is done, the spoke will leave the rim with a significant elastic bend, and the outside of this bend will have high stress. As the spoke through millions of stress cycles, this spot will eventually fatigue. It is better to create a plastic deformation in the spoke at this point (ie bend it to better align with the rim) and then stress relieve the spokes several times. Stress relieving (overloading the spokes) gets rid of the zig-zag variation of stress that occurs in any metal part that has been cold set and then not annealed. This goes for the J bend also.

As for spoke alignment and cold forging.
As Rruff already mentioned the centre drilled rims are more critical at the nipple end as they suffer from bad angles unless you give the spokes a little tweak before tensioning to try to unload the rim on the far side of the eyelet.
Very deep rims like the 68 Edge and 808 Zipp need special care at this stage as you can get 'tin canning' on the rim wall and deformation from nipples pulling at too steep angles.
I normally try to do all the prep work before putting any tension into the wheel at all, just lace it then look around at what can be done to take away as much stress as possible.
Some of the centre drilled carbon rims really need some work before I'm happy to put tension into them.
It always amazes me how little thought is often put into this part of the job, especially on mass produced wheels.
I set the nipple ends as I lace the wheel to get them somewhere near, then elbow the spokes so they sit as close the flange as I can get.
I then look at the nipple end again before tensioning, then tweak the crosses before stress relieving and maybe again after if it looks like it needs it.
I do compress four spokes near the hub to be sure the elbows are sitting nice before a final stress relieving on the block.

Leggs , going to be building some more wheels again. going to be using a 40mm carbon clincher, 20/24 with white H-2 hubs(already have hubs from another build). front will be radial with dt revo spokes and back what to try dt db 2 cross drive side and dt revo 2 cross n/drive what do you think. have done radial with dt revo but not not stiff enough, and dt db 2 cross n/drive side before, which i like but i'am trying to save some weight don't like bladed spokes that much, don't seem to be stiff enough for standing or sprinting, but are ok for everything else. whats this new thing with radial drive side and 2 cross n/ drive side , does that really work? i see some companys doing this, thought all the torque was on the drive side?. rime are 562 erd ex/nipples

stress relief-

can someone explain that part of the process....
there was talk somewhere how reynolds puts a 500lb load on the hub perpendicular to the rim, while fully supporting the rim.
What do most people do?

Stress relief is accomplished by applying an overload to the spokes. Cold worked spokes... and my understanding is that they are cold-formed and and *not* annealed afterwards... will have residual stresses. Overloading to the point of plastic deformation in these areas makes the stresses even rather than variable over the cross-section, and this significantly improves the fatigue life.

I think Damon Rinard from Trek developed that type of press (like Reynolds') in order to have a simple and repeatable method for doing this. Us small timers do it by hand in various ways. With most wheels I lay it down on soft carpet press on the spokes with my hands... one with each hand on opposite sides of the wheel... and go all the way around, then flip it over and do the other side. I usually stress-relieve each spoke ~6 times. I know I'm done when I have full tension and the wheel remains perfectly true after a round of over-loading.

Besides improving the fatigue life, it also ensures that the wheel will stay true. When this step is skipped or poorly done, some of the spokes will stretch and come loose when the wheel is ridden.

Thanks for all the replies about cold setting spokes. What I am interested in also the how - how should it be done? For example I don't understand exactly what "tweak" means. Should you only pinch the spoke with your hands? I thought of using a small piece of hard wood and pressing it onto the spoke, already in the hub, to insure an even force on the spoke.

Or a light tap with a rubber mallet? Seems a bit violent.

Your help would be appreciated.

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Bruce, sorry if I didn't explain correctly.
When i say tweak the elbow what I mean is you need to simply insert the spoke into the hub flange, push the spoke past the point where it sits in the hole, so that the result is a spoke head sitting squarely up against the flange and the spoke leaving the hole at the right angle.
As flange geometry varies quite alot the spoke manufacturers normally make their products with a very slack elbow angle, so you have to tighten it up in normal cases.
If you fit a DT spoke in a hub and pull the spoke to the correct angle to simulate the central rim you'll notice the spoke doesn't make a straight line but bows out at the hub end, this is what your trying to improve.
Also a similair method at the nipple end so the spoke leads into the rim as straight as you can get it.
Hope this helps.