Price Point has ceramic pads for the BB7; I HIGHLY recommend them. In fact, I'll never use anything else if I can help it.

Some forks are rated only for a certain diameter of disc... if you install a larger "lever" than it was designed for you risk failure.

Larger rotors are also easier to accidentally bend.

I should add that usually a larger rotor is used to disperse heat faster, not increase stopping power.

+1000 I've used BB7s w/160mm rotors on my touring bike and also several mountain/commuter bikes. If you can't lock the front wheel, or send yourself cartwheeling over the bars, there's definitely something wrong with your brake system...

There is nothing wrong with my brakes! The braking is by far the most powerful I have ever used, even on 160mm. More powerful than my Record dual pivots, more powerful than my V-brakes. Really, really good. I never had a problem with the braking, just wondering "why not more?"

I think this comes down to a definition of "lock up" the front wheel. Perhaps it is a USA meaning, but it seems most people here take that as meaning lifting the rear wheel. In that case, yes, I can do that. Easily. In fact, coming down my ramp to the parking at work I do that every day, just for kicks. Then again on the way back up. Well, this seems like a pretty strange definition to me - how can something that is "locked up" still be turning?? But, yeah, I do this. In the few emergency stops I've ever made, I lift the rear an inch or so then ease off. When I said the front wouldn't lock up, I meant skid (eg, stop turning) on good roads, I still don't think that is possible with good slick tyres.

With 203mm now, once bedded in, braking that was easy is now even eaiser. The bike feels nicer to ride. Stopping feels REALLY good. I can stop very slightly faster and the modulation is great. I love it.

As for damage to the fork. Well, for the same pull at the lever, yes. But I'm pretty sure me+bike (less than 70kg) stopping a little faster would put less strain on than some big fat guy stopping on 160mm rotors. You might argue all the more reason to keep the rotors small if I'm fit and light, but, well, WHY NOT? It feels great! The braking torque is only 25% more for a given pressure at the lever - this is less difference than the leverage difference between riding in the drops or on the hoods.

Plus, rigid forks have a lot less to strain than suspension forks. There's a hard limit to how fast you can stop no matter what kind of brakes you have (I've read in the region of 0.35ms^-2) just because of the dynamics of a two wheeled vehicle.

I wouldn't recommend it for everyone. But for me it is just a little more fun, just a little safer and just a little easier to ride now. If you are strong in the upper body to brace yourself and think you can get used to the more powerful braking (and, let's face it, we all did going from cantis to v-brakes to discs) then I'd say big rotors are worth considering.

Yes, completely unnecessary but for £15 could be the most cost effective upgrade I ever did. Given I'd have paid about the same for another 160mm rotor, well worth it.

You could just fix all of this with some good V-brakes with cool-stop pads and have stronger wheels for way less money.

There's nothing to fix. Was happy before, happy now. Never a problem with braking, just wondering "why not more?"

I don't think Vs would give the performance of discs. We had deep snow in London this year, I was glad to have brakes that still work when wet/icy. Of course, I'm sure Vs would be adequate in that I would get to work reasonably safely, but why settle for just adequte?

Well, the Schmidt hub was £170 (about $280 I think). The disc version was I think £5 cheaper. I'm using the same Campagnolo levers I already had. The fork was no more expensive in disc version. There isn't a big price difference between the BB7 and mid level Shimano V-brakes. Anyway, price isn't really an issue for me. I earn good money, I don't own a car. Saving £50 here and there just isn't that much of a priority.

Yes. Try two sizes. The difference will be obvious. I run a seven-inch rotor on the front of my Salsa Fargo because I like to use a lighter touch on the brake lever. A six-inch rotor would still stop me. I would just need to apply a bit more force at the lever.

I like having the rotor in front be larger than in the back. That sort of compensates for the difference in stopping power between the two brakes. I'd run four-inches in the rear if I could find the right parts.

I will say that a downside to the larger rotor size is that it is much easier for a bit of rotor warp to result in a "ka-ching" sound as the rotor bangs back and forth on the pads. I've had enough trouble there that I may downsize to a six-inch rotor.

The reason that the back wheel comes up is that the front wheel is no longer turning on the axle, the disc is no longer moving through the clamps.

When you stop the wheel from turning (lock it up) one of two things will happen:

1) the bike will pivot on the front wheel, lifting the rear wheel up.

2) the front wheel will start sliding.

If the former happens then this means that the friction between the front tyre and the road is strong enough that it wont slip, and the only way for your momentum go is over the top.

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You'd have to brake REALLY hard to completely stop the front wheel turning though! Try sometime when you're on a carpark or somewhere away from traffic - brake harder and harder, throwing your weight back and bracing with your arms until you are lifting the rear wheel. Don't brake so hard you go over, just so the rear lifts a few cm.

If you watch, the front hasn't stopped completely. It is just turning too slowly for the deceleration of the bike. With practice this is easy and it is a good skill to have - lets you know what your maximum safe braking is.

In any case, it hasn't "locked up" as in stoppped. That might happen on loose terrain but on good roads and grippy tyres I don't think it is possible.

I believe what the previous posters were saying is that your "maximum safe braking" should be less than the amount of braking you would get by just clamping down on the brake levers and performing a spectacular faceplant. It is VERY possible on good roads with grippy tires to completely lock up the front wheel and end up losing some teeth. The back wheel skids because the bike's center of gravity can't pivot around the back axle... but on the front wheel, if it's completely locked, the wheel can still pivot around its axle, sending you over your handlebars.

The point is, you already have the ability to brake too much if you for some reason wanted to... so you already have more brake than you need. No reason to risk warped rotors and a host of other problems just so you can have more overkill.

It is possible to go over the bars with almost any brake. I'm confident that isn't going to happen, been doing this too long. Remember when V brakes first came out? You had a lot of people saying "too powerful, can go OTB" and then the same when dual pivot came out.

The front wheel doesn't completely stop moving over heavy braking. It is just moving more slowly than the rest of the bike, hence the rear lifting.

In any case, in determining the ratio of level force to braking force, the ratio of rotor radius to wheel radius (by simple Newtonian mechanics - think two levers fighting each other) matters more than absolute rotor size. For the same braking force, 700c wheels should have larger rotors than 26" wheels.

And the difference isn't huge. Less than the difference being in the tops or the drops. you don't hear anyone say "Don't ride in the drops or you'll do an endo if you brake".

LOL! That's a great summary. Love it. Probably true.

Speaking just for myself, I prefer a very light touch on the brake. I don't want to have to squeeze hard in order to stop hard. But give me too much of that and one sneeze at the wrong moment will send me flying over the bars.

The increase in radius is from 559 to 622, and the torque curve is linear - about 10% decrease in leverage all else the same.

26" wheel w/ 160mm rotor ~ 700c wheel w/ 176mm rotor. Of course, if you're locking up the wheel on the 26" bicycle already then you're probably fine.

The 700c equiv might even be slightly less considering the braking actually happens maybe 5mm out from the centre of the rotor.

As an estimate, I'd say the drops with 2nd gen ergos give about 180% of the mechanical advantage lever-to-caliper of the tops. 3rd gen the difference is less because the pivots are higher (better design IMO)

To add an empirical datapoint to the endo debate, a few years ago I was cycling on my racing bike downhill on a country road in Wales, going pretty fast (24mph perhaps) when a van comes round the corner at a stupid speed (40mph maybe). I slam brakes and somehow get down the side. Brakes are Campy Record dual pivots from about 2002, bike is light.

Now, the rear wheel lifted a lot but I didn't go over. I'd say maybe 40cm. But before this point of it lifting I could tell it was off the ground and had started to lessen the braking. I then continued to brake with the wheel at a constant height. The modulation was there to do this.

Very, very near miss. Had twigs stuck in my levers and wheels from brushing the bush to get through. Could have been very nasty.

So... in the general case, how do cyclists go over the bars? My thinking is they don't brace their bodies properly - eg, their arms don't push back hard enough on the handlebars. Then they move forwards relative to the bike, their knees hit the handlebars and they tip the bike over.

The only time I have gone OTP backs this up. I was racing with my old club in Wales. At the end of the ride tried to stop at the side of the road. Hidden curb, all my weight on front wheel, already starting to dismount, knee hits bar, front wheel clamped and over I go. Later that day someone else punctured on the same bit of road.

Stoppie on a road bike... nicely done