[edlouie]

For all the wheelbuilders out there - in my quest to have some wheels built, I came up with some questions - any ideas?

1. Is there any benefit to lacing 3x over 2x for the rear wheel? Or is 3x just the standard lacing pattern for a 32 hole rim, and 2x the standard for a 28 hole rim?

2. Sheldon Brown claims a "hybrid" rear wheel, laced radially on the non-drive side, and 3x on the drive side will be "substantially more durable" then a traditional 3x lacing pattern in his article on wheels - http://sheldonbrown.com/wheelbuild.html#half-radial - if this is the case, why aren't all builders lacing wheels this way?

3. What's the benefit of lacing the front wheel 2x or 3x over radial?

Thanks

 

[rruff]

Generally 3x for 32 and 2x for 28 will ensure that there isn't any interferance... that's why it is used. On the drive side it is good to have the spokes as close to tangential (many crosses as possible) as you can get because it transfers torque better.

Radial spokes will not transfer torque... but really only the drive-rear needs to do that.
Radial spoking pulls straight out from the hub, so it puts the most stress on the hub flanges... but this is not a problem if the hub is designed to take the stress.
Crossing the spokes helps slightly to keep them from coming loose... but this is not a big consideration IMO, since the spokes will not come loose anyway if the tension is right.
If you radial spoke with heads in, the wheel will be laterally stiffer (small amount).
You will also save a little weight compared to x lacing.

I think Sheldon's idea about left side radial on the rear is based on one assumption: that torque on the rear wheel is loosening the left side spokes. This might be possible with heavy gauge spokes that have low tension, but it isn't generally a problem. I like to use lighter gauge spokes on the left side, which makes this a non-issue. But... radial is fine there also. Most factory wheels are built that way.

 

[edlouie]

So for the rear wheel, it seems that most builders apply the KISS rule - just use lighter gauge spokes to keep the lacing pattern the same for both sides of the wheel rather than using two different patterns on one wheel, correct? (My current set of Mike Garcia wheels is done this way)

What's the benefit of radial for the front wheel? If it stresses the hub more, and there is no real proven aero benefit, then I don't understand why people do it.

Going off topic, I don't understand why most factory wheels are built with non-traditional hubs, thick custom bladed spokes, etc, when their performance is at best identical or worse than a custom built "traditional" wheelset, with decreased reliability and repairability as well. Is it just a big marketing scam so people will waste their money on new wheels year after year?

 

[rruff]

Radial lacing is actually simpler... easy to do. I like to radial lace if the hub is new and can take the load. As I said it is a little lighter... and some people like the looks. As for aero, I doubt there is a benefit, but there might be a slight one.

Marketing hype on all these proprietary wheels? You bet. You can make better, cheaper wheels from parts.

 

[divve]

Rule of thumb is to divide spoke number by 9 to get the effective maximum number of crosses. For 28 a hole hub with common dimensions 3x will get you the closest to a tangential lacing pattern. Aside from a small weight savings, I don't see much point in having two different lacing patterns in a rear wheel. With the exception of radial non-drive side heads out, it will lead to a greater tension differentiation (read lower tension on the left). That's a more important factor to take into account compared the small improvement of bracing angle.

 

[elvisVerde]

I love this topic...

I guess I love a mystery. I can never decide what is good and what is just OK. I don't think us average Joes really know the lowdown on some of this. Somebody has got to put little strain guages and other fancy micro-measuring devices on spokes, rims and hubs and really analyze the data from a variety of wheels to figure this out, and if it has been done it has probably been someone like Mavic, and they ain't sayin'.

My take is that there is something wrong with the config of a modern road rear wheel. Too flat and tense on the drive side, and too loose on the non-drive side. It can't be good, but I don't see a mass movement to address it. Spokes are better than they used to be, and most of us don't ride abusively so we don't approach the limits very often.

When I can I try to use an asym rim on the rear, and I have also started using 2x on the nondrive side to make the spokage a bit tighter. Using these the tension between the sides is closer, but I am not sure what that proves, big-picture-wise. FWIW, my 2x front wheels seem to be more responsive than my 3x, but we are getting into subjectivo land there.

For all the wheelbuilders out there - in my quest to have some wheels built, I came up with some questions - any ideas?

1. Is there any benefit to lacing 3x over 2x for the rear wheel? Or is 3x just the standard lacing pattern for a 32 hole rim, and 2x the standard for a 28 hole rim?

2. Sheldon Brown claims a "hybrid" rear wheel, laced radially on the non-drive side, and 3x on the drive side will be "substantially more durable" then a traditional 3x lacing pattern in his article on wheels - http://sheldonbrown.com/wheelbuild.html#half-radial - if this is the case, why aren't all builders lacing wheels this way?

3. What's the benefit of lacing the front wheel 2x or 3x over radial?

Thanks

 

[divve]

If it's 2x NDS and 3x DS, they won't be tighter. It's minor, but the improved bracing angle of 2x will result in less relative tension.

When you consider most of the high-end system wheels, you could conclude that there is a mass movement to address the tension differentiation issue. It's clear they're trying their best to equal things out through creative lacing patterns and asymmetric rim designs. Because of it system wheels also typically score better than hand built traditional stuff in rear wheel lateral stiffness tests.

 

[Mark McM]

Alternate reality?

When you consider most of the high-end system wheels, you could conclude that there is a mass movement to address the tension differentiation issue. It's clear they're trying their best to equal things out through creative lacing patterns and asymmetric rim designs. Because of it system wheels also typically score better than hand built traditional stuff in rear wheel lateral stiffness tests.

Not based on any lateral stiffness tests I've seen. Based on Damon Rinard's wheel stiffness test, most system wheels are less stiff than most handbuilt wheels. The primary reason for this is simply that handbuilt wheels typically have more spokes than most system wheels. Those system wheels that are relatively stiff are so because they use deep, heavy (stiff) rims.

As noted, spoke bracing angle is of prime importance for wheel lateral stiffness. Despite the variety of claims of flange sizes or spacings or spoke attachments changing wheel stiffness, in reality the geometric constraints of the rear hub (in particular the dropout spacing and cassette width) leave very little room for variation of bracing angle. most commonly, the variable with the greatest influence on wheel stiffness is simply the diameter and number of spokes (the more spokes and/or the thicker the spokes, the stiffer the wheel). Since system wheels frequently use fewer and thinner spokes than hand builts, they end up being more flexible than hand builts.

 

[MShaw]

I've only built one set of wheels that had the rear wheel radially laced on the NDS. I forget which direction it was, but turning to one side felt normal. Turning to the other felt sloppy.

Ti spokes MAY have had something to do with this, but... right after I found this problem (I race crits, so having a wheel that behaved differently when turning is a BAD thing) I sold em to a triathlete and built another pair exactly like the first 'cept with 2x on both sides. MUCH better!

M

 

[rruff]

most commonly, the variable with the greatest influence on wheel stiffness is simply the diameter and number of spokes (the more spokes and/or the thicker the spokes, the stiffer the wheel).

Doubling the spoke gauge (and spoke stiffness) only increased the lateral stiffness by 11%. If you click on the "discussion" link for the wheel stiffness page and scroll down to #7 you'll see this:

"Thicker spokes make a wheel stiffer, if all else is equal. A typical 32 spoke wheel built with 2.0mm spokes is about 11% stiffer than a similar wheel built with 2.0-1.45mm swaged spokes.

Compare the deflection of two wheels: numbers 39 and 47. Wheel 39 is built with 2.0-1.45mm swaged spokes, but wheel 47 is built with 2.0mm straight gauge spokes. Hub dimensions are effectively identical, spoke count is the same and the rims are the same make and model, so the only structural difference is the spoke gauge.

Result? The wheel with thinner spokes deflected 0.051" (1.30mm) in font and 0.067"1.70mm) in the rear, but the wheel with thicker spokes deflected less: only 0.046" (1.17mm) and 0.055" (1.40mm) for front and rear, respectively. That's an 11% increase in stiffness for the thicker spoked wheels.

Interestingly, wheel stiffness depends on more than just spoke thickness; the rim and other factors also contribute, so only part of the increase in raw spoke stiffness shows up in measured wheel stiffness. The thicker spoke by itself is nearly twice as stiff axially as the thinner spoke!"

 

[rruff]

I've only built one set of wheels that had the rear wheel radially laced on the NDS. I forget which direction it was, but turning to one side felt normal. Turning to the other felt sloppy.

I suspect there was something wrong with that wheel besides the spoking method... there is no reason why radial spoking would make a wheel feel sloppy or unbalanced.

 

[rruff]

Just to add to the mystery...

http://www.sheldonbrown.com/rinard/wheel/data.htm

Compare #114 Campy Vento rear to #120 Shimano WH-6500 rear. Same number of same sized spokes, ~ same total wheel weight... and Campy is over twice as stiff!

 

[divve]

Not based on any lateral stiffness tests I've seen. Based on Damon Rinard's wheel stiffness test, most system wheels are less stiff than most handbuilt wheels. The primary reason for this is simply that handbuilt wheels typically have more spokes than most system wheels. Those system wheels that are relatively stiff are so because they use deep, heavy (stiff) rims.

Sure, it's easy to make a stiff wheel that's also heavy. However, according to several tests I've seen in the German Tour magazine over the years (with newer wheels than Damon's test), rear hand built wheels in the weight class of let's say Campagnolo Hyperon (~720g), generally aren't as stiff. You basically only can achieve similar results in that weight class with an asymmetric rear rim, or compensate for the dish disadvantage of a tradition geometry rim by using a significant larger number of lightweight spokes or a heavier gauge with slightly less, but still more spokes. In return you'll have to resort to a very lightweight hub in order to compensate for the weight you've just gained by using the greater number and or heavier gauge spokes. Indeed, there's no secret formula or magic involved....the main problem is that manufacturers are pretty much deliberately reserving their modern rim designs to system wheels that are much more profitable for them to sell compared to separate components.

 

[divve]

BTW, to prevent a misunderstanding. I'm of the opinion that wheels are similar to frames when it comes to stiffness. More isn't necessarily superior. It's largely dependent on the type of use, rider weight, and personal preference. For instance, I've got a pretty light rear carbon wheel of 640g that I built a while back. For me it performs flawlessly, without any brake rub whatsoever, or noticeable flex.

 

[rruff]

BTW, to prevent a misunderstanding. I'm of the opinion that wheels are similar to frames when it comes to stiffness. More isn't necessarily superior.

I would agree... if you aren't rubbing on the brake pads (and you can usually open them a bit to prevent this) then the wheel is probably stiff enough. I mean, is an extra 1mm of deflection really going to cause a handling problem?

 

[SDizzle]

...wheels are similar to frames when it comes to stiffness. More isn't necessarily superior. It's largely dependent on the type of use, rider weight, and personal preference.

Hooey...at least a little bit. My Dean with a 2" downtube and 1" stays (seat- and chain-) is a helluva lot stiffer than the Nobillette it replaced, which featured a 1 1/8" down tube and - I don't know - 3/4" tapered to 3/8" chainstays, and very skinny seatstays. I know I'm comparing steel to Ti, but there isn't that big of a difference in the stiffness of materials in tubes of the same dimensions. In this case, more is definitely stiffer.

And as far as wheels go, the 1500g-ish 2005 Eurus I used to ride aren't half as stiff (OK, maybe half) as my current 1750g-ish 32h, 2x/3x Record/Ambrosio monsters. In this case, too, more is definitely stiffer.

For a reference point, I'm 6'3", ~155 lbs, and put out 1650 watts max.

 

[divve]

The comment stated that more stiffness isn't necessarily superior.

As for tubes of the same dimension, there's definitely a big difference when the tubes are made from different materials A 1" aluminum tube is going to be far less stiff than a 1" steel tube of the same wall thickness. With carbon, and depending on the layup, a 1" diameter tube may be twice as stiff as a 2" tube.

 

[SDizzle]

The comment stated that more stiffness isn't necessarily superior.

Doing seated starts in the 53x12 or 53x13 on my Nobillette, I could throw the chain off the big ring. This was solely due to frame flex, not derailleur adjustment. And even if it didn't throw the chain, front derailleur rub in a situation like this is indicative of frame stiffness, and the issue isn't any different; I don't have this issue on my Dean.

I don't know how much racing you do, but not doing that when it counts is definitely a question of superiority.

A 1" aluminum tube is going to be far less stiff than a 1" steel tube of the same wall thickness. With carbon, and depending on the layup, a 1" diameter tube may be twice as stiff as a 2" tube.

Did you miss the distinction I made between (only) steel and Ti? I understand the difference in stiffness between aluminum and (most) other materials, and didn't mention it for a reason. I was comparing my steel bike and my Ti bike - materials with very little intrinsitc difference in stiffness - and said nothing about aluminum.

 

[divve]

I realize that it's rather a convenient method to prove your point by selecting extreme examples. I think we all realize that a noodle for a frame isn't optimal. Instead, show me some empirical evidence that a frame which has a sufficiently stiff BB performs any worse than one that's 20% stiffer? In other words a BB with 100Nm/deg versus one with 120Nm/deg stiffness....and please don't try to skew the results by using a 300lbs rider pushing 5000 watts as reference.

I didn't miss any distinction. The modulus of elasticity of Ti is around 116 GPa and that of steel is about 200 GPa. Meaning, that steel is almost twice as stiff as Ti. Whatever your frame does isn't really relevant, as it's an apples and oranges comparison.

 

[alienator]

I realize that it's rather a convenient method to prove your point by selecting extreme examples. I think we all realize that a noodle for a frame isn't optimal. Instead, show me some empirical evidence that a frame which has a sufficiently stiff BB performs any worse than one that's 20% stiffer? In other words a BB with 100Nm/deg versus one with 120Nm/deg stiffness....and please don't try to skew the results by using a 300lbs rider pushing 5000 watts as reference.

I didn't miss any distinction. The modulus of elasticity of Ti is around 116 GPa and that of steel is about 200 GPa. Meaning, that steel is almost twice as stiff as Ti. Whatever your frame does isn't really relevant, as it's an apples and oranges comparison.

Well said. The Nobillette to Dean comparison is a complete apples to oranges comparison, since there is more to the difference than just tubing sizes and materials. Once a machine performs to its design parameters, any improvements in performance don't give any benefit when those performance improvements lie outside the performance envelope defined by actual use.