Disc vs rim

[Wobblers]

While it is a fair point that the maximum amount of braking you can do is limited to the point at which you'll end up going over the handlebars (or grip, if the road surface's atrocious), meaning that it doesn't matter whether your brakes are rim or disc, this misses a few important things. The first is that in wet conditions, rim brakes need to clean the braking surface of water before they bite. That half second pause whilst your brakes think about working is a very long time when someone's just pulled out in front of you. Don't ask me how I know this! Worse, in heavy rain or spray, or when there is a lot of surface water, the rims never dry out sufficiently to get effective braking. I've been in that position and it is not pleasant. Discs do not suffer from either problem. I've just bought myself a CX bike with disc brakes for the commute because I want predictable braking under all conditions. Why would you not?

 

[ColinJ]

I must admit i was skeptical on disc brake performance but today coming down a hill in the rain i would normally take it gingerly on a rim brake bike, this morning on the disc subway i braked at the normal "OMFG will i stop " distance and was amazed at how much better they were .

Now if i could afford a disc equipped roadie or flat bar road bike i would buy it as apart the brakes the rest of the bike weighs a ton .

I descend more gingerly in the rain, not because my rim brakes don't work properly, but because my tyres won't grip as well as they would on dry roads.

Having said that - I do like disk brakes and am going to buy a CX bike equipped with them in the NY. More responsive braking is useful, but the main thing for me is that I don't like the excessive wear of brake blocks and rims in the wet, especially on winter rides when the roads have been gritted.

 

[Piemaster]

i. a rim brake will be cheaper, lighter and theoretically more reliable due to simplicity. A good bang for the buck proposition not requiring fancy dancy hubs or disc tabs on a frame, and obviously well tested over time and shown to be adequate. Can always use a regular rack too.
ii. a disc brake offers arguably better modulation and wet braking performance and has been shown to be just as reliable as a rim brake. Downsides are they are usually less bang for the buck and some designs require special racks if you need to fit one.

The cheaper bit will surely change as discs become ever more popular. Besides the machining of rims and hard facing with carbide compounds can't be that cheap either. Then there are longer term running costs, as posted by a few, a new rim/wheelbuild vs. a set of pads. Changing pads is easy, rebuilding a wheel isn't. And you still need to buy rim blocks as well. Initial purchase may be more but over time discs surely pay for themselves.

I've fitted a normal topeak rack to a disc braked bike. It did need a bit of a tweak in a vice to the eyelet ends but wasn't far off on that particular frame. I wanted it close to the frame to reduce any bending forces on the teeny 5mm bolt when used with the spacing out on disc specific racks as the bolt is inevitably longer. Important for heavier loads on the rack - like beer.

 

[jowwy]

In the new year when my new Ti disc frame arrives, all my bikes except for the TT will be disc braked. I'm even selling my spesh Tarmac sl4 and replacing with carbon disc frame. Cause as a juggernaught of a cyclist I prefer the better braking option that discs give me when descending rapidly in the Welsh mountains.

So if anyone's in the market for some nice bikes, I have a sabbath Ti 105 for sale and a spesh Tarmac sl4 105 for sale

 

[Cycleops]

The only problem I can see with discs is that the rotors themselves seem very large and could be prone to damage from a knock which could distort them and render tham inoperable. Has anybody had this problem?

 

[ColinJ]

The only problem I can see with discs is that the rotors themselves seem very large and could be prone to damage from a knock which could distort them and render tham inoperable. Has anybody had this problem?

No, but I did brand a disc-shaped burn onto one of my legs once when out on my MTB - rotors can get very hot on long, technical descents that involve a lot of braking!

 

[Wobblers]

In the new year when my new Ti disc frame arrives, all my bikes except for the TT will be disc braked. I'm even selling my spesh Tarmac sl4 and replacing with carbon disc frame. Cause as a juggernaught of a cyclist I prefer the better braking option that discs give me when descending rapidly in the Welsh mountains.

So if anyone's in the market for some nice bikes, I have a sabbath Ti 105 for sale and a spesh Tarmac sl4 105 for sale

There's always the option of getting disc specific forks and wheels so you can convert at least the front brake to disc. Of course, that may not be much cheaper than (or as much fun as) getting a new bike!

 

[jowwy]

There's always the option of getting disc specific forks and wheels so you can convert at least the front brake to disc. Of course, that may not be much cheaper than (or as much fun as) getting a new bike!

New bike frame is already on order with builders and arrives around feb/March time

 

[ianrauk]

The only problem I can see with discs is that the rotors themselves seem very large and could be prone to damage from a knock which could distort them and render tham inoperable. Has anybody had this problem?

After three years of riding discs and the rough and tumble of a daily commute and all that it brings. None at all. They're very robust.

 

[wam68]

Sorry but I go for looks first ( I know, I'm shallow ) and the disk brakes sure look damm ugly. Disk brakes would actually put me off buying a road bike. Don't shout at me now. Like I said I'm shallow.

 

[Pale Rider]

The only problem I can see with discs is that the rotors themselves seem very large and could be prone to damage from a knock which could distort them and render tham inoperable. Has anybody had this problem?

Disc rotors are easy enough to bend straight if they do get a knock.

Another advantage of discs is the trueness of the wheel is a lot less critical.

 

[Piemaster]

There's always the option of getting disc specific forks and wheels so you can convert at least the front brake to disc. Of course, that may not be much cheaper than (or as much fun as) getting a new bike!

I did that with a On-One Pompino. Difference between a canti front and a cable disc was a lack 'stop..stop....STOP!!..STOP YOU ***THING' moments at the bottom of descents.

 

[ianrauk]

As I said.. most major bike manufacturers are now making disc braked roadies

HERE (Inc. Ridley), HERE & HERE

 

[Globalti]

The only problem I can see with discs is that the rotors themselves seem very large and could be prone to damage from a knock which could distort them and render tham inoperable. Has anybody had this problem?

Nope. I've been using discs on my mountain bike for, I reckon, 15 years or longer and never had a problem despite numerous offs and mishaps. Even if a disc did get bent, as somebody wrote above, they are easily bent back. The biggest problem with discs is that the bolts that mount them to the hub are usually small and made from steel, meaning they can get siezed in the alloy hub and then the socket gets rounded out making them very tricky to remove.

 

[Pumpkin the robot]

Use better quality screws and/or change them to have a head you can put a spanner on rather than using cap heads.