Triplet or 2:1 lacing patterns

The triplet or 2:1 lacing pattern on a rear wheel is when there is 2 drive spokes for every 1 non drive spoke. The reason for this pattern is to help balance the tension difference between the drive and non drive side of a rear wheel.

A rear wheel because of the stack of gears on one side of the hub causes the flanges to not be symmetrical. The non drive side because it is futher out from the center line of the hub has lower spoke tension because if it was the same the rim would be centered in between the flanges and not the centered with outside ends of the axle. So a typical rear wheel the non drive side has about 40 to 45% of the tension of the drive side. What this causes is as the rear is being rocked around when you are riding the non drive side is going loose and then tight over and over again. The constant loosening and tightening on the non drive side causes the spokes to fatigue over time.

Take a 24h triplet rear wheel. You have 16 drive spokes and 8 non drive spokes. The 16 drive spokes are laced in a 3 cross pattern which will be almost perfectly tangent. The 8 non drive side spokes are laced 1 cross. When you take away half of the non drive spokes the ones that are left have to pull twice as hard against the drive side spokes effectively doubling the tension on the non drive side. So if the non drive was only 45% of the drive side and the triplet pattern doubles the tension on the non drive it is now only a 10% difference.

So you have the same amount of drive spokes as a 32h wheel but you have nearly balanced tension on both sides. The only downside to this pattern is that because you take away half of the spokes on one sdie of the wheel you loose some lateral stiffness. To compensate for this you must use a hub that has a wide flange spacing.

Campy’s G3 lacing pattern is a triplet pattern with the spokes gouped together instead of being spread out at equal distances. Campy claims to have invented the 2:1 lacing pattern in 2001 and patanted it. They did not invent this! This pattern has been around since the early 1900’s! Ford was using this lacing pattern to compensate for extreme disch on the model A wheels. Hi-e wheels was using this pattern in the 70’s, Roval wheels was doing it in the 80’s, Dave Thomas (Speed Dream wheels) was doing it in the late 80’s and I built my first triplet wheel in 95.

Hello world!

This is my blog to talk about all of the aspects of wheel building and I will also be showing off what I am currently building.

Ksyriums, why are they so popular?

I do not understand why the Mavic Ksyrium is so popular. They are not light, not stiff and not aero. The thing is that Mavic claims that they are all of those things even though they aren’t. Tests have come out showing that they rank very low for lateral stiffness and they ranked 2nd to last for aerodynamics in Tour magazines last test. According to the listings at www.weightweenies.starbike.com the latest Ksyrium is coming in at around 1630 grams with a claimed weight of 1530 grams. One of the odd things about them is they ride very stiff even though they are not stiff. So they give you a perceived feel that they extremely stiff when they are actually flexing quite a bit laterally.

You use to see many pro’s riding them in the european peleton but now they are rarely seen. If they were so stiff and strong (like Mavic claims) why are they not used by pro teams for the spring classics.