Disc brakes on road bikes

[Smokin Joe]

Modulation is all about the range of on-ability of the brake in a range from braking a teeny bit to locking the wheel.

rim wear... I've had mtb rims with V brakes go in three winters; heck of a lot less than 12000 miles.

If the disc gets bent and rubs you bend it back. It may distort if it overheats; folk used to rim brakes often don't understand the braking method with discs on long downhills is different. With rim brakes rider tend to drag the brake for long distances. With disks you freewheel and then brake hard, freewheel and then brake hard as dragging them makes the pads fade and the disks overheat. (but only on really long descents)

cable brakes can be tricky to adjust especially entry level ones. Avid BB5's are parp for adjusting BB7's a cinch. Hydraulic ones are self adjusting.

iirc the cable operated stainless steel front disc on my old Honda CB200 from the early 80's had a bendy disc or some such.

View attachment 109561
Not my actual bike, and this is a US one with ape hangers...

Works fine on my cable discs (all BB7's)

I had one of those back in '76. Mine was red though.

 

[Globalti]

Going from V brakes to discs on mountain bikes was a revelation; they were so much quieter, better in the wet and didn't grind your rims to grey paste. I ride my bike in all conditions so I shall be wanting discs on my next one.

 

[GrumpyGregry]

I had one of those back in '76. Mine was red though.

past my test and then only owned European marques.... but some of my best times on a bike were on that CB200...

 

[Smokin Joe]

past my test and then only owned European marques.... but some of my best times on a bike were on that CB200...

Removing the rev counter housing from the side of the head on mine to replace the little grommet round the cable because it weeped a teeny amount of oil was one of my less clever motoring adventures. Two of the little studs it located on doubled as shafts for the rockers and one of them came out with the housing. That was at the start of two weeks holiday during the long hot summer of '76 and my planed fortnight of blissful riding turned into a lesson on removing and replacing the engine, the top cover not coming off with it still in the frame. And the replacement grommet leaked just the same, a common fault on those bikes.

I still have the metric toolset and the impact driver I had to buy at the time.

 

[Trickedem]

On my recent tour from Geneva back to the UK with @ianrauk I wished I had disc brakes. We were coming down a long 10% hill in the pouring rain, with quite a bit of traffic. Limiting my speed and avoiding locking the wheels was a real struggle, whilst Ian was just dabbing away at his brakes as required. I reckon that one descent must have used about 20% of my brake pads.

 

[DRHysted]

Braking on the Allez :- Whoa.... Slow down....... brake, brake, brake, BRRAAAKKEEEEE. holy *@*t the back wheels suddenly locked....hold the skid....and breath.
Braking on the Roubiax Disc :- Do I want to slow 1 finger gently applied to the brake lever will do. Need to STOP, 2 fingers pull it sharp until the back wheel chirps as it becomes airborne. It will do this wet or dry with precision.

I'm a disc brake convert.

 

[GrumpyGregry]

^ nice description of modulation in action

 

[Tail End Charlie]

I still have the metric toolset and the impact driver I had to buy at the time.

Impact driver! That's a blast from the past, I still have mine from then (although I had a Kawasaki Z200) and don't recall using it since. I managed to wreck my engine, largely because I changed the oil regularly but not using 10W/40 I used 20W/50 and on one occasion SAE 30 (what was I thinking). The camshaft bearings wore massively, and being part of the cylinder head meant it was junk. It was also a bit of a crap design.

 

[GrumpyGregry]

Impact driver! That's a blast from the past, I still have mine from then (although I had a Kawasaki Z200) and don't recall using it since. I managed to wreck my engine, largely because I changed the oil regularly but not using 10W/40 I used 20W/50 and on one occasion SAE 30 (what was I thinking). The camshaft bearings wore massively, and being part of the cylinder head meant it was junk. It was also a bit of a crap design.

The joys of electrolytic corrosion. Alloy cases and steel bolts, with cross heads for chuff's sake, couple of British winters and... and...

 

[Drago]

I know how to set up rim brakes and have never really been dissatisfied with them. Even hauling up the awesome mass of my mighty frame in the wet isn't an issue, so I won't be rushing out this afternoon to replace my rim braked steeds.

That said, discs look to be the coming thing and as the technology quickly matures they're only liable to get better, so when the time for a new road steed does roll around (in a decade or so, a cared for bike lasts for years) then they'll be getting close scrutiny from me.

 

[GrumpyGregry]

I know how to set up rim brakes and have never really been dissatisfied with them. Even hauling up the awesome mass of my mighty frame in the wet isn't an issue, so I won't be rushing out this afternoon to replace my rim braked steeds.

That said, discs look to be the coming thing and as the technology quickly matures they're only liable to get better, so when the time for a new road steed does roll around (in a decade or so, a cared for bike lasts for years) then they'll be getting close scrutiny from me.

The technology matured at least five years ago

One way to become dissatisfied with rim brakes is to try discs

 

[Drago]

A number of my bikes do have discs thank you, and still don't blow off my Y fronts with surprise. I can lock wheels and lift the rear and im a lardy 255lb man, so I'm already able to exceed the limits of the bikes geometry and the tyre/road friction interface with fairly mundane caliper. Hence I'm lacking the urge to run to the LBS wave my wallet around and shout "me too, me too!"

Road bike discs are still maturing as a design. Look at the recent and conflicting solutions for mating the master cycljnder with the brifters. Dozens of different approaches to the problem and no clear winner yet in all the three important areas sales numbers, price and functionality. It will come, but its not there yet.

As aforementioned, theyll get close scrutiny when next I buy, but it'll be a decision based on genuine effectiveness, not being sucked into the next big cycling thing just for the sake of it (29ers, anyone?)

Hell, I don't have a smartphone and still seem able to make take phone calls very effectively.

 

[GaryA]

EDIT: Japanese motorbikes used to have stainless steel discs iirc. Not the best braking surface in the world. Steel Brembos work fine in the wet but do go rusty, until you apply the brakes.

You probably know this but they all have stainless steel discs now- what has changed since the early days is caliper design pad compound and performance as well as drilled discs-the early undrilled dics were lethal as were the god-awful sliding one piston calipers (eg on my Honda 400-4 ) The only olde world bike I had that had good brakes was a Yam RD400C (RIP wish i had it now)

 

[Pale Rider]

Flat bar hydraulic discs are well sorted - basic Shimano ones are cheap, reliable and work a treat.

As @Drago says, still a long way to go to reach that stage for roadie discs.

 

[Profpointy]

Flat bar hydraulic discs are well sorted - basic Shimano ones are cheap, reliable and work a treat.

As @Drago says, still a long way to go to reach that stage for roadie discs.

aren't hydraulic brakes very heavy?
(question, not arguing)