Disc brake road bike goodness.

[andrew_s]

I can't wait until disc brakes are commonplace on road bikes so hydraulic systems become affordable.

£125 cheap enough?

[mattc]

Having bought a cheap 'retro' low-pro TT bike with single-pivot brakes recently, even _I_ can appreciate how much better dual-pivots are!

(I'm waiting for Flatus to sell me his soot bikes cheap when he upgrades to frames with the spacing for 12-speed+discs.)

[Hot Flatus]

One of them is now a fixed gear, matt. Its brilliant 

[Cudzoziemiec]

Would a carbon frame burn? After all, it's just coal, really. Somebody must have tried... maybe Nutty knows?

[mattc]

One of them is now a fixed gear, matt. Its brilliant 

Fixed-gear? Pah - another passing trend, you mark my words ...

[mzjo]

You've probably still got an outside toilet and a bathtub too

Nope - not even a septic tank- but my father-in-law has (outside loo, bathtub, fosse septique and cooking pot over the fire).
Of course real men don't need that! they pee against the woodpile and don't ever wash

I do like my V's and I remember the GB dps on my Raleigh Riviera with a great deal of affection. The bike that carries loads has the V's (converted mtb) and they do fine and modulate as well for me as a disc.

[PhilO]

It seems that all bikes with disc brakes have the same calipers and rotors front and rear. Surely it would make sense to have larger rotors and/or more powerful pistons up front. Why are manufacturers of bicycles not doing this?

The International Standard (IS) fitting for disk brakes achieves this by positioning the mount differently front and rear. Identical callipers will use a rotor which is 20mm larger at the front than the rear. Ie, if you fit a 'front' calliper for 160mm rotor to the rear, then you need to use a 140mm rotor. Not sure how Post Mount works in this respect, though.

[Cudzoziemiec]

Interestingly, the first article google found on this puts the same thing from the opposite perspective:

A flaw in this design is that the distance from the center of the disc (the hub axle) to the caliper mount is different on the front and back brakes - meaning you need to have two unique calipers or adapters for the front and rear brakes (assuming the use of the same size rotor).
...
Again, the potential advantage to post mount is that you use exactly the same caliper for the front and back

http://www.bikeman.com/bicycle-repair-tech-info/bikeman-tech-info/1638-51mm-international-standard-74mm-post-mount

[PaulF]

Not really sure why this is an issue. I've got discs on 4 of my bikes and they all use an adapter. There's a mixture of Mount types but they all use a similar adapter that varies according to rotor size, mount type and whether it's front or rear

[Andrew Br]

With further apologies to Tiermat:-

http://www.alchemybicycles.com/bikes/xanthus-carbon-fiber-road




Shame that the rear brake mount is on the seat stay.

[tiermat]

Shame that the rear brake mount is on the seat stay.

This is one of my criteria now, that the rear disc mount MUST be on NDS (obviously) chain stay, ala On-One/Planet-X bikes.

Shame, that's rather pretty, in a stealth bomber style...

[Chris N]

It's hard to get good heel clearance on a frame with chainstay mounted cable discs, short stays and 135mm hubs.

[Sergeant Pluck]

Shame that the rear brake mount is on the seat stay.

This is one of my criteria now, that the rear disc mount MUST be on NDS (obviously) chain stay, ala On-One/Planet-X bikes.

Shame, that's rather pretty, in a stealth bomber style...

Not really an issue on a bike that's not going to have guards or a rack.

[tiermat]

Shame that the rear brake mount is on the seat stay.

This is one of my criteria now, that the rear disc mount MUST be on NDS (obviously) chain stay, ala On-One/Planet-X bikes.

Shame, that's rather pretty, in a stealth bomber style...

Not really an issue on a bike that's not going to have guards or a rack.

Good point, and those are my other requirements

In short, *if* I was to replace the Inbred 29er, the bike would need to be:
Carbon fibre
Have disc brakes, but the rear mount in the place mentioned, not on the seat stay.
Be able to take 48mm tyres (700C)
Be able to take a rack and 'guards.

Until that frame arrives, I'll keep my Inbred, thanks.

And maybe look at the Ridley X-<whatever> disc.

[teethgrinder]

Shame that the rear brake mount is on the seat stay.

Why?

My mountain bike and Hybrid with disk brakes are both seat stay mounted.
It doesn't cause me any problems.
When I put disk brakes on my Planet X road bike the disk brake mount is on the dropout bracket (which is bolted onto the frame and can be swapped for another dropout to make the bike a SS/fixer)

[tiermat]

Shame that the rear brake mount is on the seat stay.

Why?

My mountain bike and Hybrid with disk brakes are both seat stay mounted.
It doesn't cause me any problems.
When I put disk brakes on my Planet X road bike the disk brake mount is on the dropout bracket (which is bolted onto the frame and can be swapped for another dropout to make the bike a SS/fixer)

Obviously I can't speak for Andrew, but for me the problem is two fold.

1) It's and aethestics thing, I just do not like the look of seat stay mounted disc calipers
2) the chances of basking the caliper in that position, though still slim, are higher than those where it is within the rear triangle.

[Ham]

....and it makes pannier rack mounting a pain

[teethgrinder]

....and it makes pannier rack mounting a pain

Fitting my Topeak pannier rack designed for bikes with disk brakes was as easy as fitting a rack to any other bike. Disk brakes also make fitting mudguards a bit easier than it is with rim brakes.

[Furious]

I think Ham was referring to disc brake calipers on the seat stay.

One (minor) drawback to having chain stay mounted calipers is water and muck can run down the cable.

[Andrew Br]

Chain-stays are strong to resist the pedalling forces.
Beefing up a seat-stay to take a disc mounting could make the ride harsher.
At least that's my view.

Plus what Tiermat said, especially about the aesthetics 

[Ham]

....and it makes pannier rack mounting a pain

Fitting my Topeak pannier rack designed for bikes with disk brakes was as easy as fitting a rack to any other bike. Disk brakes also make fitting mudguards a bit easier than it is with rim brakes.

Yes, but your selection of panniers is cut down to...... 1 (if you want something with decent strength). So, if your needs are not met my the Topeak Super Tourist DX, you is stuffed, actually fitting it is a breeze. And yes, I'm only talking about disc mounting on the seat as opposed to chain stays.

[Kim]

How so?  Looks like a normal pannier rack to me?

[Ham]

Disc specific have built out lugs (c 20 - 30 mm?) that allow them to bolt to the dropouts but clear the disc caliper.

There are quite a few so built, but most of them have either design failings that would cause difficulty fitting panniers of different types, lack a plate on the top (not essential for use with mudguards, but useful otherwise and I think adds to the strength) or are just plain flimsy ( speaking as someone who has gone through a number of pannier racks, I have some experience). Prime failure point is the bottom rail weld. Leaving precisely 1 rack (at least, last year or the year before that was still the case, whenever it was I acquired Rocinante, my replacement Marin w/o the clever chain stay)

[teethgrinder]

Yes, but your selection of panniers is cut down to...... 1 (if you want something with decent strength).

I've used my Bike Bins and Ortliebs without any problems and I have carried some weight in them. I use it for shopping. 20kg loads isn't unusual and I've carried more. Plus I've used them for some touring.
Much better than my botched Blacburn rack on my mountain bike which has also carried full camping gear off road as well as shopping.

[Kim]

Yes, but your selection of panniers is cut down to...... 1 (if you want something with decent strength).

Reading this again, did you mean to say "pannier racks"?