Tour Mag. disc brake vs. rim brake test

Discuss light weight issues concerning road bikes & parts.
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Beaver
Posts: 512
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

In the current issue: Scott Foil 10 (stock aluminium rim) vs. Foil 10 Disc with two riders, who also switched bikes.

Nothing unexpected, e.g. full stop in the dry with 95kg (bike, rider and backpack) from 46km/h with 10% slope - disc 17,4m, rim brake 17,9m. Much more realistic than the GCN test. :mrgreen: So not the big difference, marketing tries to imply. And I'm not so sure about the braking power of the bottom bracket mounted rear brake of the Foil... that could be the missing 2,8% difference.

The rest is also nothing new: disc is 1sec faster until full braking power in the wet, has a better modulation, but is also heavier, more expensive and harder to service. And again they destroyed the 160mm Ice Tech disc with 100kg system weight, 2km slope with 12%, then accelation to 60km/h and full stop - the aluminium core melted.

So for riders in the mountains and rain it's better, but not for riders in the dry and rather flat areas - in other words most of us... And also for the Pros if one takes a look at the relation of 2018 Tour stages won on disc and rim brakes. ;)
Last edited by Beaver on Fri Aug 03, 2018 9:54 pm, edited 1 time in total.

by Weenie


hannawald
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Joined: Sat Dec 17, 2016 7:28 pm

by hannawald

maybe also better for your expensive carbon wheels:)

spdntrxi
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Joined: Sat Jul 20, 2013 6:11 pm

by spdntrxi

sad that the rotor was toast.. better then the rim ofcourse but not like RT900S rotors are extremely cheap.

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Beaver
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Location: Lower Saxony - Germany

by Beaver

They just wondered why Shimano won't offer 180mm discs for heavier riders.

And it's a pity they didn't also test Enve or Bontrager carbon wheels with textured brake tracks for comparison.

We have seen a lot delaminated carbon rims in the past, but what about newer Zipp Showstopper, DT Swiss or Campy/Fulcrum AC3?

There are plenty of those on the roads and at least some must be ridden hard in the mountains, or not?

I don't think those can be "killed" that easily...

romanmoser
Posts: 146
Joined: Sun May 06, 2018 8:30 pm

by romanmoser

well even if shimano offered them

they wouldn't fit on the frame and fork
the brands build them for 140 or 160 in flat mount

Post mount allows 180

Would like to have them tested the dura ace rotors

I don't know about their testing but I was fine on transcontinentale race with 8 kg of bikes bags ...
And 160/160
65 70kg bike 8,5 kg without bikepacking gear and aero extensions
SO it's fine for me and my practice

TobinHatesYou
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by TobinHatesYou

I’ve tested DA rotors, H11 rotors and Centerline X rotors. The Centerline X were the best, least finicky overall. Quiet, no warping, compatible with any pad shape/size, no discernible difference in friction force, won’t melt like Shimano rotors.

dvq
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Joined: Mon Sep 25, 2017 1:36 pm

by dvq

Beaver wrote:
Fri Aug 03, 2018 9:49 pm
And it's a pity they didn't also test Enve or Bontrager carbon wheels with textured brake tracks for comparison.

...

There are plenty of those on the roads and at least some must be ridden hard in the mountains, or not?

I don't think those can be "killed" that easily...
I rode a set of ENVE 3.4s with the rim brake textured brake tracks 500,000 ft of descending (of course I had to climb those feet first) in a little over a year of weekend rides, the brake tracks were noticably worn down from new after that amount of descending. Likely the texture would be almost completely gone after 1M feet. They were a warranty replacement that ENVE gave me after I melted a set of 6.7s with the old brake track. I wouldn't say I'm heavy on the brakes either -- all descents were done in good weather (no rain), and I place in the fastest 2% out of 9,000 , so I can't really be using the brakes that much.

I'm on disc brakes now, at least it costs $40 to replace a rotor instead of $1000 for one rim :)

TobinHatesYou
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by TobinHatesYou

ENVE’s heavily textured brake tracks also chirp quite loudly...sounds like an incoming missile when slowing down from speed. Zipp Showstopper is silent under all conditions I hear, but offers slightly inferior braking. My front disc brakes have the tiniest whistle from road grime and the rear is silent. Yes, they honk when wet and cold, but that’s something I can live with.

My descending confidence even went up slightly just moving from SRAM HRD to Hope RX4s.

romanmoser
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by romanmoser

So you manage to melt a rotor from shimano ?
May I ask was it doing a test like Tour
Or normal riding ?

I saw also the result from the test but I don't know anymore where the sram were first
I really hated the sram force cx1 I tested on a cross tough

I could be interested in coupling hope flat mount caliper to ultegra DI2 levers when I build a cx/allroad bike again soon 160/160
And then try with dura ace rotors vs sram centerline
On the road bike where I live with my weight 140/140 are all I need , I could use a 160 upfront when going to the moutains I guess

The dura ace look like they have more material and tech in it with their freeza tech etc
Maybe it's just bullshit :D ...
Last edited by romanmoser on Fri Aug 03, 2018 11:51 pm, edited 1 time in total.

TobinHatesYou
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by TobinHatesYou

romanmoser wrote:
Fri Aug 03, 2018 11:34 pm
So you manage to melt a rotor from shimano ?

May I ask was it doing a test like Tour
Or normal riding ?
No, I haven’t personally...I don’t think I could. Just acknowledging the fact that it’s happened to people who really suck at descending.

dvq
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Joined: Mon Sep 25, 2017 1:36 pm

by dvq

romanmoser wrote:
Fri Aug 03, 2018 11:34 pm
So you manage to melt a rotor from shimano ?

May I ask was it doing a test like Tour
Or normal riding ?
No issues for me, I've used both centerlinex rotors and the dura-ace rotors. Both have been fine for me, centerlinex makes a less noise.

romanmoser
Posts: 146
Joined: Sun May 06, 2018 8:30 pm

by romanmoser

Ok thanks

The reviews I see online are all good about hope RX4
Except this one from you end of june this year :mrgreen:

'' Alright so I have had quite a saga with RX4s and I haven't even gotten to ride them yet.
About a month ago I ordered front and rear SRAM compatible RX4s from my LBS through QBP. They arrived, I installed them. The outboard small piston on the rear was completely stuck. I could immobilize the three other pistons and force the stuck piston to advance, but not without making grinding noises every time. Pushing the piston back in was even harder. I managed to do it a couple times. I tried using brake lube to free up the movement. Nothing worked. I had a shop mechanic look at it, he ended up cracking the piston (which is ceramic.)

I sent it back to Hope's USA office to get it looked at and replaced. I knew this was going to take some time to get back to me, so I ended up just buying another rear caliper to use in the meantime.
Well that second caliper I purchased had a leaky bleed port. It would seal with my bleed kit syringe, but not with the included grub screw. I contacted Hope USA again and they threw a grub screw in with my warranty replacement caliper, which I got today. My first step was to test the leaky caliper with the new bleed port screw (and after q-tipping the port.) Nope, still leaks. So I mounted the warranty replacement and that bled fine. However after trying to set my pad distance, the same freaking small outboard piston was exhibiting the same behavior. Completely stuck, moves only when the other 3 pistons are held in place...makes grinding noises when it advances.

You know the Top Gear joke about English craftmanship? Apparently it pertains to Hope bicycle components too. Needless to say I'm pissed. ''

and also from dvq who's on this post now too :D
DVQ are you back for good on sram or do finally the hope RX4S work ?

Thanks

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

by TobinHatesYou

romanmoser, dvq tried 140mm while descending a couple weeks ago and did not like it. Admittedly he was borrowing someone else’s slightly worn rotors, but I personally feel that’s one of the last places to worry about shaving grams.

And yes, I was not happy with the quality control on the RX4s. The first set I had, I let a shop install them for me and both calipers ended up with stuck pistons. I got replacements from Hope and the same thing happened. I bought another caliper because the warranty process from Hope UK -> Hope USA -> me takes weeks and that one had a leaky bleed port.

I finally got a pair of working calipers after 2.5 months. These work well for now, but who knows how long that will last? dvq’s RX4s got dirty and the pistons weren’t advancing properly...he tried to clean the pistons and they got cocked in the bores. He’s back in his SRAM HRD calipers now.

Apparently the pistons aren’t even ceramic...they are phenolic resin (plastic.)

If Magura makes 4-piston road calipers, I’ll probably switch to those immediately...

robertbb
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Joined: Thu Jul 23, 2009 3:35 am
Location: Melbourne, Australia

by robertbb

What pads were they using on the aluminum rim?

Also would have been interesting to see how a DT Oxic rim went... probably would close the gap even more.
It's ALL about the bike.

RobertBB's CyclePlanner Spreadsheet:
https://weightweenies.starbike.com/foru ... 8&t=152263

romanmoser
Posts: 146
Joined: Sun May 06, 2018 8:30 pm

by romanmoser

Damn
Disappointed I tought they were good looking and if they worked out as well as promised why not
But I think I'll pass thanks to you too for being '' testers '' ;)

by Weenie


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