When Are Disc Brakes Necessary?

Discuss light weight issues concerning road bikes & parts.
User avatar
Calnago
Posts: 6551
Joined: Sun Nov 07, 2010 9:14 pm

by Calnago

@Bordcia... how many rims have you ever worn out a rim from normal braking? I mean give us a number. And carbon is much harder to wear through than aluminum. Aluminum is relatively very soft. Personally I have never worn out a carbon rim, and only one set of alloy rims that I used for loaded multiweek touring. I specifically asked this exact question in a thread quite some time ago just to see who is really wearing out carbon rims. The response was like next to no one.
As for the last part of your question, if disc brakes were all we had for the last 50 years, then all of a sudden rim braking showed up, I’d bet the marketers would be all over it....
- save 500g
- no more bleeding hydraulic lines
- no more finicky pad/rotor adjustments
- swap wheels in an instant
- quick release, no more thru axles required to stabilize uneven forces on the stays and forks from discs.
- frames can be lighter, or the same weight but stronger since that 500g can now be added back to the frame, thus stiffening up things where it counts... in the frame.
- the racers choice
- “neutral support” now really means neutral support.
Yes... it would be a much easier sell than disc brakes appear to be.
Colnago C64 - The Naked Build; Colnago C60 - PR99; Trek Koppenberg - Where Emonda and Domane Meet;
Unlinked Builds (searchable): Colnago C59 - 5 Years Later; Trek Emonda SL Campagnolo SR; Special Colnago EPQ

by Weenie


CEVelo
Posts: 95
Joined: Tue Mar 24, 2015 5:22 pm

by CEVelo

Just get one of each and pick the based on ride.
Rims are great for flat rides or rides with rolling hills.
Hit the mountains and disc are hands down preferable.

ome rodriguez
Posts: 336
Joined: Fri Feb 24, 2006 9:16 am

by ome rodriguez

CEVelo wrote:
Wed Jul 11, 2018 4:25 am
Just get one of each and pick the based on ride.
Rims are great for flat rides or rides with rolling hills.
Hit the mountains and disc are hands down preferable.
It’s the other way around in the pro peloton.

flying
Posts: 1525
Joined: Mon Dec 19, 2005 9:16 am

by flying

CAAD8FRED wrote:
Sun Jul 08, 2018 10:37 pm
What situation would you say calls for discs over rims?
That would be never Fred :wink:

flying
Posts: 1525
Joined: Mon Dec 19, 2005 9:16 am

by flying

Bordcla wrote:
Wed Jul 11, 2018 2:07 am
Do you seriously think the marketers could sell us rim brakes as an improvement if discs had been the commonplace option for the last 50 years?
This is after all weight weenies so I have to say H*ll yes they could sell as as a lightweight improvement with more than enough stopping power
speed modulation etc. :thumbup:

Antoine
Posts: 502
Joined: Tue May 03, 2011 6:36 pm
Location: France

by Antoine

Calnago wrote:
Wed Jul 11, 2018 2:56 am
... how many rims have you ever worn out a rim from normal braking?
some years ago I went in Ariège near the Pyrénées with a group, we did some climbing but not so much.
It was raining often and one guy ruined his Hyperion clincher in a few days.
However he didn't bother to clean the brake pads and the rims after riding,

tarmackev
Posts: 240
Joined: Sat Jan 15, 2011 9:59 pm

by tarmackev

Antoine wrote:
Calnago wrote:
Wed Jul 11, 2018 2:56 am
... how many rims have you ever worn out a rim from normal braking?
some years ago I went in Ariège near the Pyrénées with a group, we did some climbing but not so much.
It was raining often and one guy ruined his Hyperion clincher in a few days.
However he didn't bother to clean the brake pads and the rims after riding,
I get 2 seasons from my wheels, I live in a hilly area with lots of roads that have a dead stop at T-junctions.
I wasn’t for discs at all until I sold my best bike and had to ride my disc CX bike on the roads for a few months.
I realised I was no slower on the rides, checking the speeds I was making a lot up on descents.
On the rim brakes I’d start squeezing as the hills steepened and by the junctions at the bottom my levers would be pulled tight.
With the discs the power is more consistent, the bite is harder and it’s easier to hold the tyres right on the limit of their grip.
That’s what gets it for me, with discs I can feel tyre on the edge, with a rim brake it’s much easier to lock up.
I feel discs will be everywhere soon, arguably more aero on the flats, hidden hydraulic cables etc.
The only downside is the wet.
Adjust the pads and calipers takes me no longer than adjusting brake blocks and calipers.
Bleeding takes 20 mins a brake (maximum) every couple of years.
Changing pads is quicker.
Through axles take 15 seconds each. I’m not racing so that’s no problem for me, even when I was a flat out me out of contention anyway.
Honestly the only negative is weight.
It’s nice to be able to ride my best wheels in any conditions without worrying about wearing the rims out.

Are discs necessary, not really, are they better, yes.

I wonder how many people are commenting on this thread without riding discs extensively on all terrains and in different weather conditions.
A rescuer/opinion isn’t valid unless you have experience using the product.


Sent from my iPhone using Tapatalk

Marin
Posts: 3004
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

Image

Molten Shimano disc from descending without cooling stops

Broady
Posts: 302
Joined: Thu Jan 03, 2013 5:02 pm

by Broady

That's no fault of discs, I'd imagine if he used the same terrible braking technique on rims he'd probably puncture or delaminate the carbon.

Multebear
Posts: 1148
Joined: Sat May 02, 2015 10:11 pm

by Multebear

Calnago wrote:
Wed Jul 11, 2018 2:56 am
@Bordcia... how many rims have you ever worn out a rim from normal braking? I mean give us a number. And carbon is much harder to wear through than aluminum. Aluminum is relatively very soft. Personally I have never worn out a carbon rim, and only one set of alloy rims that I used for loaded multiweek touring. I specifically asked this exact question in a thread quite some time ago just to see who is really wearing out carbon rims. The response was like next to no one.
As for the last part of your question, if disc brakes were all we had for the last 50 years, then all of a sudden rim braking showed up, I’d bet the marketers would be all over it....
- save 500g
- no more bleeding hydraulic lines
- no more finicky pad/rotor adjustments
- swap wheels in an instant
- quick release, no more thru axles required to stabilize uneven forces on the stays and forks from discs.
- frames can be lighter, or the same weight but stronger since that 500g can now be added back to the frame, thus stiffening up things where it counts... in the frame.
- the racers choice
- “neutral support” now really means neutral support.
Yes... it would be a much easier sell than disc brakes appear to be.
+ 1

I like this. And agree. Friend of mine rode 30.000 km on Bontrager carbon wheels and sold them. They definitely showed some wear, but they still had at least 10-15k km in them. That is more than enough. And rebuilding the wheels with new rims after full wear isn’t that big of a deal, if you are even keeping the wheels that long.

And Totally agree about manufacturers pushing rimbrakes if it was the other way around. And we would be stupid enough to buy into there marketing BS any day.

Multebear
Posts: 1148
Joined: Sat May 02, 2015 10:11 pm

by Multebear

tarmackev wrote:
Wed Jul 11, 2018 8:52 am

Are discs necessary, not really, are they better, yes.
I think you pretty much nailed it here. In other words discs are definitely nice to have, but not need to have.
Last edited by Multebear on Wed Jul 11, 2018 9:40 pm, edited 1 time in total.

TobinHatesYou
Posts: 1773
Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Broady wrote:
Wed Jul 11, 2018 9:29 am
That's no fault of discs, I'd imagine if he used the same terrible braking technique on rims he'd probably puncture or delaminate the carbon.

Looks like that guy probably never changed his pads and the rotor was grinding on backplate or perhaps the caliper body was very misaligned. Rest assured nothing actually melted there. Hydraulic Press Channel put a rotor on a high-speed lathe. It got red hot, the hydraulic fluid boiled and popped the hose right off. Nothing melted under utterly synthetic loads.

C36
Posts: 323
Joined: Fri Mar 03, 2017 3:24 am

by C36

tarmackev wrote:
Wed Jul 11, 2018 8:52 am

Are discs necessary, not really, are they better, yes.
You clearly have a “need” as Per OP’s question. If I had to do full stops several time a descent at a T-junction I would likely accept loosing in frame riding quality.
“Best” would apply to the complete bike and so far the disc degrades how frames “rides”, I had it mentioned on an earlier post with Cannondale and Canyon engineers or just here from Le Cycle comparing 3 pairs of identical bikes but the braking system Image.
For the comment on “who really ride discs”, I don’t on the road but had the chance to ride 2 super six evo hm “identical” to mine (one one size bigger the second the same, mine upgraded on few things).

Envoyé de mon iPhone en utilisant Tapatalk

Marin
Posts: 3004
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

TobinHatesYou wrote:
Wed Jul 11, 2018 11:41 am
Rest assured nothing actually melted there.
These are 100% actually melted Shimano steel-aluminum-steel sandwich discs, I assure you. Tour & bike magazine also had this happen during their stress tests (13% descent, 90kg rider, dragging the brakes and then emergency stop).

Of course, with proper technique and a lighter rider this won't happen!

https://www.google.at/search?rlz=1C1GGR ... v7LDr5oZOM:

https://www.bike-magazin.de/komponenten ... a3738.html

User avatar
tymon_tm
Posts: 2576
Joined: Tue Sep 05, 2006 4:35 pm

by tymon_tm

necessary? in road racing/cycling? never.

helpful? yeah, sure I bet you can find occasions when discs perform better, like rainy days and such.

since I'm about to change bike for a new one, I was exploring my stance on discs, searching for a way in for discs in my riding. I haven't found any, despite I'm getting used to the looks and IMHO some rides, like the new Spec, look awesomely cool with discs. but the thing is - brakes are the last thing when I spec or think about a bike. frame, wheels, drivetrain, saddle, tires, bars, tape, pedals... ah, yeah, I forgot about brakes. I can use anything really. truth be told, since I build bikes myself, last time I bought new brakes was like 10 years ago... still rocking Ultegra 6600, which have been on few bikes already. of course I do change pads, but that's really it. rim wear? sure, stuff does wear, but I never ever had to change wheels because of that.

since brakes are the least important component, and braking itself isn't quality I bother with, and neither have I ever felt my brakes lack anything on any occasion, IMHO discs are not only pointless, but kinda downgrading too, cause they weight more, and are more complicated to deal with (my wife has a disc trekking bike, I freakin hate to work on it).
kkibbler wrote: WW remembers.

by Weenie


Post Reply
  • Similar Topics
    Replies
    Views
    Last post