CX Disc Brake / Di2

[jerome]

Hi,

I am thinking about a new Moots CX Psycho RSL

I would like your advice on the following possible option

- Disc brakes
1/they look to be the future but are they really an improvement ?
2/what is the weight penalty at this stage of the technology?
3/which Hubs ? rear width ? 130 / 135 / ?
-Di2
1/ Inside or outside ?
2/ any experience with a Di2 modified to accept an XTR cassette 11/32


other proposition welcome

the bike won't be made for racing only I intent to use it as I already use my others CX bikes all-around, climbing remote cols in the Alps (to get the best cheese ever and ... raw milk ! - everybody welcome )
thank you

best

[Marcusaurelius]

If you live in a very wet, muddy part of the planet then disc brakes are the way to go.

The 135mm hub is very easy to find, the 130mm not so much. I didn't see any advantage to 130mm.

[jerome]

I am lliving in the french Alps Annecy

It is wet but not that much it is not Belgium ! and I am not a mud fanatic when It get too muddy I stay on farms roads or take my MTB
I have a MX RSL suited with a Niner rigid fork for this.

The weight penality is hudge betwen a disc DT 240 and a non-disc 240 130mm or betwen a CK ISO 135 and a CK 130mm

How much is the weight penality for disc at the end ?

best

[VA-Scooter]

I have a Lynskey Cooper CX with disc and Ultegra DI2. Certainly not the lightest bike but I love it more every day. Use it for road & gravel-switch tires a bit but it only takes a few minutes. I have heard it can handle 32 rear but have not tried it. I have run 12-25,11-28,and 11-30. All work just fine. Disc brakes & internal wires make a real nice bike that is real easy to clean up. I would guess the brakes & DI2 add about a pound or so each. So at most the bike weighs 3 pounds more than it could. My bike is never the limiting factor in my riding. With street tires I ride with the same group & I can put cross tires on & go play in the dirt on the same bike. For disc hub selection 135 makes the most sense.

[AngryScientist]

if you're actually riding in the alps, which it sounds like you are, i would shy away from disk brakes, definitely.

i dont know if they have improved at this point, but there was certainly a lot of problems surrounding disk brakes and overheating and failing on long descents. it is no secret that i think disk brakes are not necessary and not the right choice for most bikes, but riding disks on road in the mountains, especially lightweight disks could very well be a safety issue, one which might have very serious consequences. consider also that wheel changes give you less freedom with disk wheels.

[ergott]

There will be an Alchemy disc brake hubset soon. There will also be a Chris King R45 disc, but I don't know what the rear spacing will be for that yet.

The weight penalty will be less. Definitely get 135mm spacing whatever you do.

[oldpotatoe]

if you're actually riding in the alps, which it sounds like you are, i would shy away from disk brakes, definitely.

i dont know if they have improved at this point, but there was certainly a lot of problems surrounding disk brakes and overheating and failing on long descents. it is no secret that i think disk brakes are not necessary and not the right choice for most bikes, but riding disks on road in the mountains, especially lightweight disks could very well be a safety issue, one which might have very serious consequences. consider also that wheel changes give you less freedom with disk wheels.

Think that's a primary concern with wet/hydraulic discs, not mechanicals.

The newer wet brakes that were supposed to be unveiled at interbike by sram didn't make it for some reason. Looking at a mockup, no real cooling fins or features, long descents on a road wet/hydro disc is gonna be interesting.

Have a local guy who writes for Velonews with 2 Moots cross bikes. One disc and one canti. In CO, he races the canti one almost exclusively because he doesn't like the disc weight 'penalty'. He says he can tell the weight issue, and in a tough race, he doesn't want to deal with it. If it's sloppy, then the disc but in CO, it's almost always dry.

[jerome]

thank you

yes all this will evolve really quick it is just a matter of time.

135mm rear width seam making more sense mechanically

Ck hubs are awesome but DT match them easily

and you have a bunch of workshop ready for the move.

the only question is what Mavic or others main manufacturers will do ?

a 700 135mm disc wheel in not something they have in house
and a 29 inch disc wheels won't made it either

and they are the guys showing hte direction


best

[blantonator]

it's going to be 1-2 lbs heavier. Once hydraulics come out that will shrink a little, but you will still have a 90 gram rotor on each wheel and the disc hubs add another hundred grams.

[ergott]

the only question is what Mavic or others main manufacturers will do ?

and they are the guys showing hte direction


best

Seriously?

Mavic isn't they only player by far.

People have used Enve XC rims laced to disc hubs which is essentially a 29'er wheelset. You could use any 29er as a set for cross wheels.

[VA-Scooter]

Put-2012 Cooper CX Di2-in Google search. Pretty close to what you are thinking about. Should be the top entry from Lynskey's Facebook page.