Wednesday, February 17, 2010

Weight Weenie $/gram record?

Cervelo has announced a new special project frame, Project California, a frame much like the R3 and R3-SL except with a claimed mass at a super-impressive 700 grams in size 54. Announced price for the California (which I'll call the "R-CA"), presumably for stock sizes, is $9000 US.

Project CaliforniaDamon Rinard shows the Cervelo Test Team the new Project California frame

Now, 700 grams is impressive and all. But I judge mass savings based on the marginal cost of attaining them.

Usually mass is confounded with functionality, but on the Cervelo R-series, with identical geometry and similar ride characteristics, I think it's safe to say the upgrade progression is mostly a weight weenie play. So I'll resist the temptation to compare it with the Guru Photon, a fully custom frame of comparable mass at half the price. Maybe the Cervelo is simply better. But comparing to the other Cervelos in the R-series, to which Thor Hoshovd himself claims the ride is similar:

frame
list price
grams @ 54 cm
R3
$3100
867
R3-SL
$4000
803
R-CA
$9000
700


It's all about marginal cost, though. That is trivially calculated:

R3 → R3SL: 64 grams @ $14.07/gram
R3SL → RCA: 103 grams @ $48.54/gram

To put $48.54/gram in perspective, a bottle of Odwalla juice costs around $3.50. But by this gauge, what's the real cost? Suppose I drink a bottle of Wholly Grain I don't need: 400 kcal. That will cause a weight gain of around 52 grams. At $48.54/gram, that's $2500. Wow -- that's a helluva cost multiplier! It's pricier than a typical price of my 860-gram Fuji SL/1 frame. Indeed you can get a SRAM Rival-equipped Scott Addict at Bike Connection in Palo Alto for less, pedals included.

So how will climbing improve, day in, day out? Here's a typical weight variation, measured with a high-end body mass scale (from the DC Rainmaker blog):


Day to day weight for this guy, a highly trained triathlete who carefully weighs himself the same time each morning, is up to around 800 grams. When riding, you sweat around 500 grams per hour on a hot day. Even if you drink from a water bottle to replenish this, the weight is coming off your bike or you, one way or another. In the time it takes to climb Old La Honda, therefore, you're probably dropping around 150 grams: more than the mass difference between the R3 and "Project California". Just think: in the time you climb Old La Honda on that hot summer day, you increase the value of your bike by $7300. That's $6.75 per second of sweating.

And before you tell me weight on the frame is so much more important than weight on the body, why do you carry your water bottles on your frame as opposed to on a belt? Q.E.D.

I love weight weenieism: no question about it! But my limit is around $4/gram. With that as a crude limit I've gotten my race bike down to just below 5 kg. $58/gram? Insane... There's so many cheaper ways to save that mass, off the bike, off your shoes, off your helmet, off your clothing, maybe even off your body. And watch out for those Odwallas.

But I still admit I think it's cool.

6 comments:

Bryn said...

A 5kg bike? I gotta know, what's your setup?

djconnel said...

I linked to it in the blog post.

Nothing extreme, really. The biggest factor is the wheels, built around Edge 1.24's. Edge 1.25's are newer and maybe a bit lighter, though.

Bryn said...

Hey, small world. I recently installed some Edge 1.25 tubulars, w/ DT 190 hubs. Shaved about 1.5 lbs over my previous wheelset. I thought my bike was light at 14.1 lbs. What size bike do you ride? What frame?

The only areas I can think of shaving more weight is the saddle (65g for a superlight carbon shell, not feasible for long rides, I know because I tried it.), gel handle bar wrap (??g , again comfort over weight) bike computer (??g but then I would know how much faster I was going :) Everything else in kinda important... drop the water bottle cages?

So instead I'm focusing on me, I'm working to loose about 10 lbs by August.

All part of my goal to do OLH in less that 20 minutes. I thought I was a bike geek for writing a perl script to calculate cadence for every possible gear combination given a target OLH time. I'm thinking the next step is to integrate your drive train loss data and add power computation. :)

djconnel said...

I love my Becker carbon saddle. Very light, no padding at all, but it fits, which is key. No forgiveness on fit on hard-shell carbon. If it fits, great, if not, bad.

Also swapping quick releases with KCNC, using a Lightning crankset, and using Power Cordz cables with Alligator iLinks housing all took off big chunks of mass. Then sticking with 26 mm handlebars (Al bars) with an Extralite Al stem made for a nice light combo for less than the price of a single carbon bar. Then a Recon Al cassette was another big plus: substantially cheaper and lighter than Red. Just less durable.

The bike is size "small": a 52 cm effective top tube.

Yes -- the best bottle cages are no bottle cages :). I got my cages from Ebay from Taiwan. Fairly light and very cheap and they work well. I typically use one in hillclimbs.

Bryn said...

I ride a 54cm bike, somewhere around a 55-56cm effective size.

KCNC quick releases: check. Nice piece of design.

Bars and stem! Yeah, while not heavy I'm haven't made any attempts to carve weight off this part of the bike. Ritchy Al w/ anatomic bend, 42cm. Carbon bars (for the same *actual* size) never claim to be lighter than Al, but a whole lot more expensive. Stem is also Aluminum, but the comparable Carbon one was only 10-15gs lighter...

Cables... something to think about.

Crank? Carbon Record. My concession to vanity. :)

I think I'm having salad for dinner tonight... much cheaper than new bars, cranks, and cables!

Rainmaker said...

Happen to stumble on this...thanks for the shoutout!

Interesting stuff - I always think of it in terms of water bottles, but never even considered the sweat angle at all. Despite even going to a presentation covering California. Nicely done write-up.