If you need a couple wheel rotations to dry the rims before your brakes are fully working, then tire traction is not the main issue. The first guy goes down, but the next ten guys can't stop fast enough, and go down too.

Another wrinkle I failed to mention: I would like to carry over my dynamo setup from the previous bike. The disc frame is a thru-axle (QR15). That would mean buying another hub. The "cheap" option is like over 200 bucks just for the hub, plus a pretty penny for the rims and spokes. I can build them, but still.

I'm starting to think budget and timeline might be the deciding factor here. I could always build another disc bike in the future.

The V-brakes I had on the previous bike with good pads were STRONG. I was never lacking in power. I guess I would just have to avoid 50+mph descents in wet weather.

EDIT: To be more specific, the first pads on the bike were some really cheesy pads with the stock, low end tektro cantilever brakes. I carried those pads over to the V-brakes and it stopped better, but it wasn't until I swapped the pads for some DA9000 pads that the stopping was magical.

You make it sound like it's disc brakes or die. Yes, they are better. In the mud very much so, in the rain slightly. More weight, more cost, better performance.

I've run BB7s for years on various bikes, I'm not really a fan. They work well, but setup and maintenance is a bit of extra hassle. I don't like brake rub and a lot of things have to come together to avoid it easily and completely. They aren't more powerful than the caliper brakes I have on my other brakes, though more consistent in all conditions. They are a bit harder to modulate, but that's a minor thing. I keep them because I don't like buying rims every spring, but even with that hassle my next bike will almost certainly be caliper. Unless I get really fancy and go hydro, but it's expensive for a winter trainer.

I was biking in a thunderstorm yesterday, and an idiot pulled out in front of me. My old breaks would not have stopped me that quickly. My hydraulic disc breaks did.

They are loud when wet, but its really nifty watching steam roll off them when you stop at the bottom of decent.

From my experience, having a non-true wheel doesn't effect breaking, unlike in the case of rim breaks. I took my bike in today to have a spoke repaired and tire trued. The guy said he's never seen damage like that on a rim of that quality. I'm not sure what I hit. Last semester was the last for my master's degree and everything was a bit of a blur. What I do know is that my breaks were fine.

As for mechanical vs hydraulic... I don't know. You have finer control with the hydraulic, but is it worth it to you? I don't know. For me, the fine control is very nice.

I went disc and never looked back. Why bother with a through axle fork? For years people rode MTBs with disc brakes and 9mm QR hub, how can it be an issue for road bikes? There's lots of options available, I'd find one with a 9mm QR fork and keep your dyno hub.

Like I said, I already have the frame picked out, so it's not a matter of finding a different disc frame. Thru axle is what it comes with.

Also, the hub I have now is not a disc hub. So again, not really making a difference.

When I bought my previous cross bike, I was convinced that I didn't want disc. I think it was the overall aesthetics of the bike and what I did with it. Discs would have looked out of place on that build. In reality, the rim brakes were fine, but this bike will see wet weather...

I keep trying to tell myself I can use my rechargeable lights, but once you've ridden proper dynamo lights, you know that's not true. And with that as a requirement, it's really pushing the budget.

disc brakes are better. choice of control is wire or hydraulic. wire is hard to find but good simplicity.

There is no reason for a disc commuter bike to be ultra-heavy duty fat tyre tourer. There are plenty are light, agile aluminium CX style commuter/doitall bikes, with discs, rack, fender mounts and clearance for max 35/38mm rubber.

Thru axles provide structural support for suspension forks in heavy use. On a fixed fork commuter, you really don't need them. Is there a mature standard for axle diameter yet?

The frame I'm planning on is a lightweight aluminum CX bike, so I agree that it doesn't have to be a heavy fat tire touring bike. The last build I did with fenders and dynamo lights was something like 23 pounds. It was freaking awesome.

I don't see why people are suddenly so apprehensive about thru-axle forks, though. The tech has been around awhile now and it has its benefits. Necessary for commuting? Heck no. But the frame I want has it, so that's what it has.

Yes, drum brakes solve the 'require maintenance to work well' problem by 'just never working well'.

(And, if the fleets of bike share bikes are any indication, they do require adjustment, because the brakes vary wildly from bike to bike.)

I've been fine with mine since the 80s.. Sturmey Archer elite .. I dont need brakes that can front stoppie me into a faceplant..

Shimano's is a grease filled thing , like a coaster Brake .. with a Hand lever.

When you are talking about disc brakes, there are noticeable benefits, but with thru-axle, it's not so clear. It will stiffen up the fork and frame a bit, which is good, but probably only beneficial if you are racing. The main issue is locking yourself into a developing technology for road bikes, when the standard QR is perfectly fine.

I did a little dance when I retired my bb7s many years ago.

I do. I almost never use them that way, but it's very good that I can, when I have to. Brakes that can't make a bike do an endo are inadequate for road use.

I ran BB7's for years. They worked fine but you have to stay on top of the pad adjustment to keep good braking power. I'm a daily commuter, 40 miles/day and I had to adjust mine at least weekly to feel like I had top stopping power.

I looked at full hyros but the price for the brifter versions are eye watering.

I settled on TRP HY/RD mechanically actuated hydraulic discs and I really like them. Self adjusting, self centering, good modulation/stopping power, reasonable price. I have over 20K miles on mine and am a very happy customer.

If one has the skills to not kill themselves with brakes that powerful, they also have the skills to not kill themselves if they aren't.... If not, it won't make a difference.

That's a pretty low bar, in the dry. The last bike I had that didn't have brakes that good was a bike with 16" wheels and only a coaster brake.

Good brakes have saved my bacon a few times, and I see no reason to use defective by design brakes.

Interesting point. I'll be sure not to ride too close to other bike commuters on any descent if I get caught riding in the rain, so I don't crash into any ahead of me. Can't do anything about those who might be behind, though. The "silent drafter" is a known problem in my area - just the other day, I accidentally forced a cyclist off the MUP when I passed a pedestrian. I didn't know he was there when I passed the ped, he apparently decided at the same exact time to attempt the double-pass and ended up riding off the trail.

That's what "lifesavers" are for: looking over your shoulder just before manouvering. Whether you signal or not, whether it is a right or left move in your lane, always look over your shoulder. Saved me dozens of times so far.

I almost always take passing lane position in time to brake and abandon the move, if there turns out to be someone trying to pass faster without caring - whether it is another cyclist, or a car, motorcycle. Once I've moved to the left enough to pass, I just keep going straight, without moving an inch more left.

Yes, I learned my lesson for sure. Never trust the behavior of others on the MUPs.

When I built a custom frame as my dream/ultimate commuter, I certainly had an option to go with disk brakes. But no, I did canti/v-brake studs instead. And not even once have I ever exclaimed "Good godz, I wish I'd gone with disk brakes!" Not that the weight makes a huge difference at all, but I don't mind saving a few ounces and sacrificing overkill-level braking power.

Not that this means I won't change my mind five times again, but....

In the process of acquiring this new frame, I went back to the shop I worked at to build bikes once a day on the weekend. I have a M-F gig, but right now, if I want to do anything out of budget, I have to find other ways. All that to say that after building up some bikes of varying builds (awful caliper brakes, good caliper brakes, V- brakes, mechanical disc, a couple of hydraulic discs) I pretty firmly decided against mechanical disc. Dialed in V-brakes feel fantastic. Mechanical disc brakes are a pain due to only the outboard pad moving in and out. Hydraulic would be nice, but would require basically a whole new group at this point.

That and like I said before, a canti frame means I have everything else I need on hand. A disc option requires saving up for a wheelset and brakes. And I really want this bike by the end of September. We'll see if I change my mind again.

And thinking back to my last CX commuter/touring build, the V-brakes were perfect. It did get ridden in the rain and I never found myself wishing for more stopping power. Cleaning off black gunk is going to suck, though.

So yeah, I talked myself back into disc brakes. It looks like I can make the money happen by mid-September, so I think I'm going to go for it. I'll be sure to post a separate thread once I get it built up.