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theoretical / technical wheel build question(18 posts)

theoretical / technical wheel build questionDougSloan
Jun 13, 2002 10:52 AM
I've heard over and over that rear drive side spokes should never be radial because there is more torque on that side. I could never come to terms with that. It seems to me that the entire hub turns as a unit, and the drive side can't be twisting any harder than the non-drive, unless the hub itself is twisting.

It just occured to me, after reading some info on wheel building, that the drive side spokes are under much greater tension. Therefore, if a spoke is going to break due to torque from the hub, it's because it's already under greater tension, not because there is greater torque on the drive side. That make sense?

Of course, Ksyriums are radial on the drive side, but I guess they are so different that the same rules don't apply.

Doug
Sounds right to me...Nessism
Jun 13, 2002 12:13 PM
...but then what do I know?

I was surprises at how much difference there is in spoke tension between the drive and non-drive side. For that reason, I started to use Revolution spokes on the non-drive rear since they are so lightly stressed.

So the next question is, what are you going to build? I've been thinking about building a value oriented performance wheelset using medium low spoke count semi-aero rims. Any thoughts?

Ed
what I'd like to doDougSloan
Jun 13, 2002 12:17 PM
I'd like to build a "wet weather" wheel set using Open Pro ceramic rims and Record hubs. Damn, though, I priced the parts out using 14/15 spokes and it comes to about $450. Plus, I gotta spend about $350 in tools to get started.

Doug
$350 in tools?Nessism
Jun 13, 2002 12:41 PM
Park TS-7 truing stand w/dish tool = $70
Spokey nipple wrench = $7 (not sure)
Brandt book = $25

This is all you need. You don't even need the book since about 3/4 of it is not very useful. You can get lacing information off the internet from Sheldon Brown.

So how are you getting up to $350? Are you including a tension gauge? If you are, it's not necessary for the wheels you are planning to build. Low spoke count aero wheels, maybe yes. Conventional wheels, no.

And you might want to think twice about the ceramic rims, the coating chips easily leaving a bump, bump, bump each time you brake. Also, the coating EATS brake pads like crazy unless you spend the money for special brake pads - pain in the butt. Of course, please check for yourself about the rims. rec.bicycles.tech has a long thread on this subject.

Good luck.

Ed
what I calculate / ceramic rimsDougSloan
Jun 13, 2002 2:01 PM
Oh, this is what I was considering:

Park TS-2 truing stand = $160 (didn't several recommend this?)
Dishing Tool = $20
Spokey nipple wrench = $7
Brandt book = $25
Tension Guage = $90

$302 (probably close to $350 with shipping, etc.)

Ok, I guess I exaggerated.

I don't have a mechanic's fine tuned hand nor a musician's ear. I wouldn't have a clue if a spoke was tensioned correctly. The problem, I see, is that sound can tell you the spokes are tensioned *equally*, but not necessarily *correctly*.

Maybe I'll "get it" after reading the book.

As far as the rims, I have several other wheels for most uses. I was thinking of these times when it's damp or raining, and I'm plunging down mountains at 50 mph and need all the brakes I can get. I've used ceramic mountain bike rims, and found them to be fantastic wet or dry, and had no problems with chipping. As little as I'd actually use these, I doubt it would be concern.

Thanks.

Doug
ToolsChen2
Jun 14, 2002 7:11 AM
Doug, with the TS2 stand there really is not a need for a dishing tool, honest. You'll never even use it. And I think you can built great wheels without a tension gauge. I can see where a tensiometer could help with getting an entire set of spokes in the right ballpark, but when it comes to perfecting radial true and lateral true it's the geometry that dictates tension, not the other way around. I know some good professional wheel builders who never use a tensiometer. And I'm sure others will disagree with me. I suggest that you try building with the TS2 stand without a dishing tool or a tension gauge before deciding if you need those.
After building several wheels this year I can now lace a 3X wheel in 30 minutes, but then I'll spend 1-2 hours bringing up the tension, truing radially and laterally, and stress relieving. The Brandt book is great, but there are only about 5 pages you really need for lacing up a wheel, it's really simple. And it's a fun hobby.
Park TS-2Nessism
Jun 14, 2002 10:54 AM
While this stand has a mechanism to center the wheel, it's not very accurate. If you adjust the stand to center a 100 mm hub it will be slightly off when building a 130 mm hub and visa versa. A dishing tool is still needed.

I agree that the tension gauge is not needed to build conventional wheels. It would be nice if building low spoke count wheels howevers. Honestly though, if I had an extra C-note burning a hole in my pocket, a tension gauge would be a very nice purchase.

Ed
Park TS-2 and Dishing toolsCalvin
Jun 14, 2002 1:03 PM
The TS-2 should do an adequate job dishing, but for accurate work, a dishing tool is recommended. The TS-3 is able to replace a dishing tool. The TS-2 can do just as accurate a job when used with a dishing tool. For use of a dishing tool see http://www.parktool.com/repair_help/howfix_truing.shtml By the way, even new wheels should be checked for dish.


Calvin Jones
Park Tool
Park TS-2 and Dishing toolsChen2
Jun 16, 2002 6:53 PM
Thanks Calvin. I bet I can center a rim just as accurately, within a fraction of a mm, using only the TS-2. But I haven't tried a dishing tool yet, so I could be wrong and I should not be recommending my technique to others since I haven't actually used a dishing tool. My mistake.
~Al
Rain Wheelsgrzy
Jun 14, 2002 1:37 PM
Hey, if you're plunging down the mountain in wet weather and the brakes don't work to well what does that say about the friction between the tires and the road surface? Do you really want to be descending at 50 mph on wet or damp roads? Just remember you need to swap your brake pads when you switch between ceramic and non-ceramic rims. Question: If everyone is so obsessed with climbing wheels how come no one builds _descending_ wheels? ;-b It's a rhetorical question.

The ca'ts meow would be to use disc brakes on a road bike, but the design issues of the frame and fork have to be addressed first and then there's the weight issue. I'm kinda surprised it hasn't caught fire by now - the technology and parts are there and is being proven on tandems and now CX bikes. Avid even makes a cable disc now with the correct leverage ratio to be used with non-linear pull brake levers (i.e. road). Anyone who's spent any time in the MTB world can really appreciate and atest to the difference.

You're right on the tools to buy - some purists will maintain that all you need is a spoke wrench, an old bike frame, and some duct tape. It's much easier with the nice tools available. I would add the "Wheelbuilding" book that is out now - more instructional than Brandt's book. If you can get your hands on the training manual for the DT/UBI courses taught in Portland, OR you'll find it quite helpful. the important thing to realize is that it takes practice, time and experience to build decent wheels. It's better to stick with some less exotic designs in the beginning. When it's all done you really won't save any money - do it if you want to learn new skills and have the patience to fiddle around until you get it right. You'll soon realize that paying a skilled builder $40 per wheel built is a bargain.
...riding your own set of wheels = priceless (nm)Stampertje
Jun 16, 2002 3:59 PM
Seems excessivepmf1
Jun 17, 2002 4:16 AM
Everyone serious about bike riding ought to have a truing stand. Taking wheels to a bike shop is expensive and worse ... time consuming. Even if you decide to skip wheel building, buy the stand (a good one) and learn how to true wheels. Its not very hard to do. Loosen one side and tighten the other. Once true. check for roundness. A truing stand is basic equipment like a repair stand. I'd wait on the dishing tool and tensiometer. They aren't necessary for building a set of wheels.

As far as wheel building goes, you cannot buy the components cheaper from places like Colorado Cyclist or Excel as you can the complete wheel. And those guys build pretty good wheels. Building your own wheels will not save you any money, nor will they be better than what an experienced builder can do. Its time consuming as well (don't you have a kid on the way?). There is a feeling of accomplishment though. I first got into it because I had a lousy set of wheels on this cheap Cannondale I bought and I got sick of hauling them down to the bike shop. Later, another set of machine built ones I got from Performance lost all spoke tension and I decided to try to rebuild them . I got away from it because of the time involved. I'd rather be riding.
re: theoretical / technical wheel build questionJekyll
Jun 13, 2002 12:57 PM
supposedly (according to Gerd Schraner) the non-drive side spokes are more likely to break because they have less tension. He claims that spokes brake from play between the spoke and the hub and from insufficient spoke tension - by work hardening the spoke head against the hub. He also claims that you cannot brake a spoke by applying to much tension (using a standard profile rim - he claims that you can apply upwards of 270lbs (and 450 on deep profile rims) of tension to the spoke without causing damage though you would probably destroy the rim by doing it). I can't say I've ever broken a spoke on a wheel I've built, but I am hardly an expert on the subject.
so...DougSloan
Jun 13, 2002 1:53 PM
Are drive side spokes more likely to break than non-drive side? Is that only a myth?
so...Jekyll
Jun 13, 2002 2:20 PM
I don't have any statistical data either way. I would guess that the drive side is probably more prone to braking due to the lack of dish and the additional drive line stress on that side. I think that a lot of builders don't put enough tension on the drive side as well complicating things further.
Someone like Bianchi4me (Mike Garcia) could probably give you a much better answer then that.
Drive vs. non-drive spoke breakage.Spoke Wrench
Jun 13, 2002 3:33 PM
I think that in the olden days, drive side spokes were more likely to break. Since the advent of 8, 9 and 10 speed cassettes, I think that has changed. The issue is lack of tension on the non-drive spokes.

A highly dished wheel will have much more tension on the drive side spokes than on the non-side. If you put more tention on the left side spokes, you also have to put more tension on the right side spokes or the rim won't be centered between the lock nuts. Eventually you will reach a point where you can't tighten the drive side spokes anymore without rounding the nipples or possibly even damaging the rim.

The window at which the non-drive spokes have adequate tension and you can still adjust the drive spokes, is rather narrow. Sometimes wheelbuilders don't get it right.

When drive side spokes break, it's generally for some reason other than inadequate tension. If the drive side spokes have inadequate tension, the non-drive spokes will have even less tension and, consequently, are likely to break first.

One common reason for drive side spokes breaking is shifting the chain into the spokes. Do that, even once, and you will booger up the 8 outside spokes. They'll be weaker at that point and more subject to breaking. That plastic spoke protector gizmo really does serve a purpose. Other common problems are burrs on the hub holes and too many spoke crosses. Spokes that are crossed too many times enter the rim at too much of a tangent and tend to break off at the nipple.
Good Question - Don't know the text book answer, but...jose_Tex_mex
Jun 15, 2002 3:34 PM
I can easily see one side of the hub twisting more - especially the drive side. My friend has a rear rim with both radial and cross patterns. They stopped making it as it was a disaster. Off hand, I so not know which side was which.

As for "drive side can't be twisting any harder than the non-drive" I would say that it couldn't possibly be twisting any less. The only problem here is theory vs reality and how much the strength of materials makes up.

As for tension vs torque, I would think that the spokes would be ridiculously strong tension wise (logitudinal forces) and not so much wrt torques. However, I guess the two beating up the spokes is what does it in the end. How these factors relate would be fun to study.

I really want to study the cross lace like on the Shimano 535's. I have over 3K on mine and they are still perfectly trued - still from the factory. It almost worries me that these rims will either be perfect or dead. We'll see...
Your reasoning sounds, uh, reasonable.Leisure
Jun 16, 2002 2:30 AM
I never did understand why so many people forwarded the argument that somehow one side sees more torque than the other. On a wheel laced with one radial side, the torque on the hub will be imposing basically the same changes in tension on the spokes regardless of which side is radial. The difference is that those spokes will see twice the change in tension that a wheel cross-laced on both sides would, since half as many spokes are translating the torque from the hub to the rim. I don't know how much this really hurts longevity in practice, but in terms of theory I don't much like it.
But if you're really determined and you're just trying to choose which side gets the radial lacing, I'm not really sure what to think as to which way is better. I haven't seen enough people destroy their blended-laced wheels. My rear mtb hub was originally laced in 3x drive side and radial non-drive. It was actually quite pretty and it didn't break, but I didn't like the feel of it. I had Mike at my LBS relace it in 3x both sides and I like it much better. He said he felt basically the same things I did when he had that arrangement on his road bike. My friend has it on his mtb and he also came to the same conclusion.