Tuesday, August 18, 2009

cost-mass tradeoff on 2010 groups

I did a few minutes of data mining of the Competitive Cyclist road group configuration page, collecting datapoints in each of the three available full-group manufactures, SRAM, Shimano, and Campagnolo. The page offers convenient totals on mass and price. Their mass numbers aren't always great, and certainly even local shops often beat Competitive Cyclist prices (especially with bike coalition or racing club discounts), but the idea is to compare the relative cost of different groups, and it is assumed discounts are available for each.

First, on this comparison, it's clear Shimano is uncompetitive. SRAM comes out the best, with Campy a close second.

But second, sticking with complete groups, the jump to the highest end comes with a hefty price tag. Each is over $5/gram. Among the second-tier groups, Force shows itself as the real weight-weenie bargain. With performance essentially equivalent to Red (with exception of the ceramic bearings, which might be important), it sacrifices less than 150 grams.

And it's easy to make up that weight for less money than the Red upgrade. For example, I show how swapping the Force crankset for a Vumaquad comes out lighter than Red at less money, even though the Vumaquad is a boutique-level crankset. The Lightning crankset could yield the same mass as the VumaQuad at around $350 less. However, I was sticking with parts Competitive Cyclist sells. In any case, the Lightning gives up some stiffness to the SRAM cranksets, and while crank stiffness isn't a big deal for my power and mass, the stiffer Vumaquad makes my point better.

Competitive Cyclist price-versus-mass comparison


Ron said...

Dan : You should have called this Retain Price vs Group Weight. The total cost of any group is to be added over its complete lifecycle., in maintenance and repairs. Just for instance, the campy shifters can usually be overhauled when the parts wear out (usually the springs), whereas a provision like that is not provided in a Dura Ace shifter. There is value in this not captured by your graph. Certainly there is more to the story than just upfront costs. The other hidden costs are often neglected by us.

djconnel said...

True, which is why cost/mass on a chain or cassette shouldn't be weighted the same as on a brake or shifter. But I don't have relative reliability data for the groups. Certainly SRAM drivetrain parts are not as durable as the others (SRAM placed a high priority on low mass), but the low mass on the shifters is a result of their simpler mechanism (only one motion, versus two on Shimano and Campy). I don't know the availability of spare parts for SRAM, although at the prices Campy charges, for stuff a few years old I suspect full replacement via ebay becomes competitive with repair, unfortunately. But the fact the parts are available is certainly a plus.

Ron said...

Total cost of a chain (or tires, tubes etc) to me is cost I pay for it plus the costs I incur for maintenance. If it fails causing injury or if its recalled, the costs are way higher and I couldn't possibly define it as there is an emotional element to those costs.

Speaking of which, if you're shopping for or are using SRAM Red, be aware that their chain powerlinks have been called out to have the capacity to fail. There was a recall on it by SRAM and CPSC a few weeks ago. Great blog! Keep the thoughts coming.