2013 Bikes

Sorry, missed both your replies as I'd gone to bed. Thanks for the explanation, but It wasn't the basic big disc/rim = more leverage = greater force part of the design that I was unclear on*. My query was whereabouts these forces were being applied to the fork legs.

*I'm aware that I could well be talking to a physicist here, whilst my degree is in photography ;-)

Quoted from Jobst Brandt ( Admittedly about 7 years ago! )

"With rim brakes forks are loaded in bending at the fork crown that similarly supports road shock, while a disc brake places an equal bending torque at the tip of the fork and only on one blade. The fork can only be slender and light because it carries no bending loads at the dropout. With disc brakes forks would require a substantial increase in cross section (and weight) and brake would be heavier".

"With rim brakes forks are loaded in bending at the fork crown that similarly supports road shock, while a disc brake places an equal bending torque at the tip of the fork and only on one blade. The fork can only be slender and light because it carries no bending loads at the dropout. With disc brakes forks would require a substantial increase in cross section (and weight) and brake would be heavier".

This is true, fork legs need to be stronger but not by a huge deal, this does not contradict the notion that larger rotors put less stress on the fork. Remember that the calipers and their mounting brackets fit to standardised positions on the fork less. I.S.O or Post Mount etc.. So its not like the caliper is placed in the centre of the fork leg. But the few MM of position adjustment the mounting hardware allows changes the leverage it has against the hub.

Also dont forget that people fit heavily loaded lowrider racks bolted around the centre of the fork leg (the weakest point).
And they do sometimes fail when the rack is poorly designed without a front brace like this;

http://forum.ctc.org.uk/download/file.php?id=11493&sid=231cae45a74dd452e730fa55cd7f437d&mode=view

But if they have the front brace the forks never break.

http://www.flickr.com/photos/mmeiser2/3056988352/

The thread appears to be derailing a bit & I've exhausted my extremely limited mechanical knowledge, so here's another 2013 bike. Albeit a disc braked model :-)

A more affordable aluminium alternative to the carbon SuperX that Dammit posted on page 1.

https://sslcache.se/23bff0cff28a3da2bcf370ff89dd677606d5d664/?url=http%3A%2F%2Fi1074.photobucket.com%2Falbums%2Fw408%2Fbarenecessities1%2Fcannondale-cross-bike-2013-img_0074-e_1copy.jpg

I think it looks rather more toned down than the carbon model.

^^ That makes sense. Thanks!

Loads of factors to take on board when specifying discs- well outside my abilities to describe well, but taking a stab at it:

• Weight of rider and bike (downhill bikes are heavy)
  
• Grip generated by the tyres and surface
  
• Speed needing to be shed
  
• Frequency of heavy braking
  
  

If you take a look at your average superbike it'll have twin massive rotors at the front, a trail bike typically only one.

Again, a rally car will have tiny brakes when compared to a road car.

The speeds you typically attain on the road, and the repeated heavy stops when compared to "speed modulation" off-road require brakes that can shed speed (as heat, essentially) more effectively on road than off.

Imagine ripping down a trail in Morzine on a downhill rig with 203mm rotors, then doing the same descent on the road- would you really want 140mm rotors to stop you, repeatedly, from 60mph?

I've only overwhelmed the grip of my 32c slick tyres once with my hydraulic 160mm rotors, in a very hard stop down a very steep hill- the two chaps behind me with rim brakes didn't make it and went through the hedge on the outside of the corner.

I want that Cannondale frame.

^^ Cheers! Personally I've always been more than happy with 180mm front & 160mm rear ( hydro or mechanical ) on my bikes. I think I'd most likely pass out once I went beyond 50mph!

I want that Cannondale frame.

Buy it for your new wheel ;-)

Considering these for the CX bike and then never spending money on it again.

^I like the fact that they have a user replaceable battery, but £1000 is still a bit scary. I think I'll get one of those kurt kinetic things first.... Just to see if I can power a lightbulb yet!

Has this been up yet?

https://sslcache.se/6d082e931ebcf6ce07f43d814561b9eefa5ba8e0/?url=http%3A%2F%2Fi1074.photobucket.com%2Falbums%2Fw408%2Fbarenecessities1%2Flynskey-helix-os-limited-edition-sram-red-road-bike1.jpg

Limited edition of 30. Twisty Helix tubing is definitely Marmite though!

This one looks more my kind of thing! Articles are from June, but I seemed to have missed them.

https://sslcache.se/30ac968339b9090ba07928483fd54b0f0969b7a0/?url=http%3A%2F%2Fi1074.photobucket.com%2Falbums%2Fw408%2Fbarenecessities1%2Fdk200bike-1.jpg

http://www.dirtragmag.com/webrag/anatomy-gravel-race-bike-my-dirty-kanza-200-rig

• Possibly a Ti version!
  
  

http://ridingagainstthegrain.com/2012/06/04/analyzing-the-salsa-ti-prototypes/

Are the Specialized bikes in the Road Race the 2013 S-Works? They seem to have gone back in design with Specialized on the downtube and S-Works on the toptube.
Look fucking awful

These look very clever.

"Designed and manufactured in Germany, the “Smart Spindle System” has been developed in co-operation with Tune and offers the ability to mount the cranks into any of the following bottom brackets:

BSA68, ITA70, BB30, BB-Right StandardFit, BB30-OS-Specialized, PF30, BB386EVO FSA, BB-Right PressFit und Pressfit BB86."

Get that in 110 bcd and you could run 52/36 rings with 50/34 in reserve and you've got pretty much the most flexible crankset with power.

Some more tempting items in the new Salsa line-up.

http://www.dirtragmag.com/webrag/salsa-details-full-2013-bike-lineup

I particularly like the new stainless steel Vaya. ( Not the build )

With S&S couplers

& alternator dropouts for singlespeed/fixed.

This one looks more my kind of thing! Articles are from June, but I seemed to have missed them.

http://www.dirtragmag.com/webrag/anatomy-gravel-race-bike-my-dirty-kanza-200-rig

Am I seeing things or is the rear brake mounted to the driveside?

Am I seeing things or is the rear brake mounted to the driveside?

just you

Loads of factors to take on board when specifying discs- well outside my abilities to describe well, but taking a stab at it:

• Weight of rider and bike (downhill bikes are heavy)
  
• Grip generated by the tyres and surface
  
• Speed needing to be shed
  
• Frequency of heavy braking
  
  
  

I now have a nice selection of brake brake sizes in the works. My personal feeling is that a big rear disc is too easy to lock. So I always go smaller at the rear.

SS 29er - 160F / 140R
Works well. Definitly on the border of being too small, but they modulate well.

Longbike - 203F / 180R
This bike is mad heavy, and will be loaded with ~160 Kg of rider + kids + baggage.

Fatbike - 203F / 160R
Trying to get a good combination of control and power. Not really sure how to relate the disc size to 4.7" studded tyres, and ice. That seemed as good a bet as any.

what kind of adapter would I need if I want to try a bigger front rotor?

Depends if it is post mount or IS I would think- what mount have you got?

looks like IS to post mount?

You can get IS to post mount adapters that account for different disc sizes I believe.

Of course, I may be talking out of my cloaca.