Weight Weenies

ave wrote:The backplate originally has a function, I'd think, no?
What keeps the chain on the upper pulley? Just those shallow teeth?

No "backplate". The thin metal "wire" is there to open up the RD a bit so that parts are better visible.

For you who are interested in the whole making here is the link (in German) but with a bunch of photos also how it is mounted on the bike.
http://www.forum.light-bikes.de/showthr ... 16&page=17

Visit starbike.com Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

www.starbike.com

bura,
I see that there is no backplate.
But I think the backplate have a function on the original, it's not just something to be left off to shave a few grams.

The chain might come off the jockey wheels after hitting a pothole while shifting for example. I might be wrong, never tried it.

Reminds me of the 916 when it first came out.

Carbon coil spring! The whole thing is crazy. In a good way.

Ok but as you can see there is nothing like the original. As we can expect these pulleys sit much more rigid in the cage plate centered with those big "rims". And personally my concern regarding the chain in this application would be with the lower pulley which can be made somewhat safe with a as short as possible chain and a parelelogram spring with more tension.

There's two types of weight weenies: (1) those for who weight is everything. (2) performance weenies who place a high value on the advantage of lightness. I think this succeeds wonderfully at #1 but for #2, I agree it falls a bit short. For one, those pulleys look like bushings rather than ball-bearing based, and that adds significant friction if so. Second, I agree the rigidness may be a concern: it the pulleys come out of alignment due to lateral loads then it will twist the chain which may contribute to drivetrain loss.

When I contemplate getting a Dremel and taking it to my Red derailleur, which has very good (perhaps not the best available... watching those Tiso bearings spin @ NAHBS was truly impressive) pulleys, I wonder if the decrease in rigidity will offset the 10 grams or whatever saved. With many parts I can justify decreased strength or stiffness based on my body mass which is well below the design point for mass-market equipment, but the derailleur load is mass-independent.

It would be interesting to send this to Friction Facts, which from what I can tell does the best testing out there right now.

where can I buy one?

I'd like to see video of it working. I guess if it's form over function - it wins out on those stakes massively - looks amazing but who knows how it really rides except the builders and the owner

I agree with Ave,
I feel it would need a back plate to be reliably ridden, Not just up and down the street. Looks good as a show piece though?

dereksmalls wrote:I'd like to see video of it working. I guess if it's form over function - it wins out on those stakes massively - looks amazing but who knows how it really rides except the builders and the owner

Agree, video of it functioning would be cool to see....

Maybe y'all should ask them for a video?
There is a thread over on light-bikes after all.

prendrefeu wrote:Maybe y'all should ask them for a video?
There is a thread over on light-bikes after all.

True, it's a great thread detailing it, a bit hard to run the whole thing through google translate but the pictures are awesome!

love it

That is so beautifully done I could not ride it only use it as a show piece of engineering.

this a badass tunning and a piece of art. Unrideable on a bike though. It would brake in 3, 2, 1... sad but true.