Disc Brakes

[jabberwocky]

Disc brakes are, in almost all cases, significantly more powerful than rim brakes.

[hozn]

@Brünø Moore 82803 wrote:

Those of you running the mullet setup: why put the disc up front?

As Jabberwocky mentioned, the disc is the brake that provides more stopping power. BUT the other significant reason people put the disc up front is because the only reason they are doing the “mullet setup” is that their frames don’t have disc mounts — i.e. cheaper to buy a fork with disc mounts then to find a new frame.

[mstone]

1) it’s generally a heck of a lot cheaper to retrofit a disc fork to a non-disc frame than buy a new frame and keep the fork

2) you’re putting an enormous amount of weight into one company’s marketing material, which is tailored to their specific bike designs and focused entirely on use in tandem racing bikes.

3) this company is mainly complaining about the power of mechanical drop bar brakes, which are known to be less powerful than hydraulics or even flat bar mechanical brakes. for a single bike this generally isn’t really an issue as the brakes still stop the bike.

4) other tandem manufacturers disagree with santana and sell dual disc tandems

5) commuters often go the front disc route specifically because in that situation the disc is often the much more powerful brake, being less affected by rain/snow/etc, and to reduce wear on the front rim when running through wet/gunk/etc.

horses for courses

[jabberwocky]

Their web page is somewhat misleading, as well. They say that a 700c rim has a “3:1 advantage” over an 8″ rotor, which may be true from a purely theoretical standpoint (the rim is technically a much larger diameter disc than a rotor). But that completely ignores the fact that a rim is thin and hollow and therefor you can’t actually clamp it very hard without damaging it, whereas a disc rotor is solid steel and can be clamped extremely hard with no issues.

It also ignores the fact that heat buildup is much more of an issue on a rim than a rotor (discs getting really hot just means the disc gets really hot, whereas rims getting really hot can mean that the tire blows off the rim. I know this has been an issue with loaded touring bikes on long descents; some tourers actually recommend taking periodic breaks to let things cool down if you’re descending for long enough).

I’m not that familiar with tandem land; I know that there are plenty of issues with braking in general there (the requirements are super high compared to normal bikes), but from what I see they are mostly disc these days.

[mstone]

@jabberwocky 82811 wrote:

It also ignores the fact that heat buildup is much more of an issue on a rim than a rotor (discs getting really hot just means the disc gets really hot, whereas rims getting really hot can mean that the tire blows off the rim. I know this has been an issue with loaded touring bikes on long descents; some tourers actually recommend taking periodic breaks to let things cool down if you’re descending for long enough).

No, they are well aware of overheat issues. All brakes have really ugly failure modes. Blowing a tire off a rim is bad, and can result in injury or death on a high speed downhill descent. Setting your hub grease on fire, boiling your brake fluid, demagnetizing your pad retainer, or melting your carbon fork are all bad, and can result in injury or death on a high speed downhill descent. You can’t prevent catastrophic failure from bad braking technique. Luckily most people don’t ride much in mountains, and most bikes are built with a decent safety margin and used by people not pushing the limits.

[peterw_diy]

Front disc brakes also put a lot of stress on the fork for really heavy bike+load setups (cargo bikes, maybe also tandems; Yuba puts bigger rotors in back). Sure, you can just make a beefier fork to compensate, but it sounds like Santana thinks it’s not worth the weight & trouble since cantis worked well for years and V brakes are even better.

[rcannon100]

Installed the rotor and the caliper. Removed the old cable and realized I had grabbed a road brake cable, and I have mountain brakes. Le sigh.

Removed my top tube protector (keeps top tube from getting scratched up when parking) only to find a toy surprise from the previous LBS repair. They left a HUGE gash on the top tube. They made several mistakes. They didnt put on tire tape; I blew a tire last tour de fat. And then they gashed up the top tube, and just put the tube protector back on to hide it.

[Bruno Moore]

@hozn 82809 wrote:

As Jabberwocky mentioned, the disc is the brake that provides more stopping power. BUT the other significant reason people put the disc up front is because the only reason they are doing the “mullet setup” is that their frames don’t have disc mounts — i.e. cheaper to buy a fork with disc mounts then to find a new frame.

Ah, this makes sense. I figured that, like most anything one reads on the Internet, “disc brakes on the front are ungood” should be taken with a grain or three of salt (it’s not what I’m used to seeing, to say the least), hence why I asked. It seemed like a big “might be true in theory, good luck in practice” kind of argument, to be honest.

[dasgeh]

@rcannon100 82872 wrote:

Installed the rotor and the caliper. Removed the old cable and realized I had grabbed a road brake cable, and I have mountain brakes. Le sigh.

Removed my top tube protector (keeps top tube from getting scratched up when parking) only to find a toy surprise from the previous LBS repair. They left a HUGE gash on the top tube. They made several mistakes. They didnt put on tire tape; I blew a tire last tour de fat. And then they gashed up the top tube, and just put the tube protector back on to hide it.

Was this the LBS that everyone hates closest to my house, or another one?

[Author]

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