Disc Vs Rim Braking System

member054
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Re: Disc Vs Rim Braking System

Postby member054 » Mon May 01, 2017 11:28 pm

My last bike (2009) came with hydraulic discs and I've loved them - the power and smoothness.

The negative for me, having never maintained anything hydraulic apart from the garden hose (and I live in Brisbane, we weren't allowed to use garden hoses for a while) was to learn the maintenance side. But once you've done that and realise how easy it is to align after a wheel swap, I guess all that's left would be weight and/or aesthetics concerns.

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Comedian
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Re: Disc Vs Rim Braking System

Postby Comedian » Tue May 02, 2017 7:05 am

member054 wrote:My last bike (2009) came with hydraulic discs and I've loved them - the power and smoothness.

The negative for me, having never maintained anything hydraulic apart from the garden hose (and I live in Brisbane, we weren't allowed to use garden hoses for a while) was to learn the maintenance side. But once you've done that and realise how easy it is to align after a wheel swap, I guess all that's left would be weight and/or aesthetics concerns.
I noted on the weekend that my rear alfine hydraulic disc is ineffective now, and just makes a little noise (and the lever is lower). I haven't looked at it yet, but I'm guessing it's a leak from the slave cylinder, which if it was like the front, will require replacing the calliper and lever due to the Shimano no parts ever policy. Sigh. :cry:

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Re: Disc Vs Rim Braking System

Postby jacks1071 » Thu May 04, 2017 11:09 am

Magura used to make a hydraulic rim brake that'd out brake any modern disc in the dry.

Only problem was the rims had to be really decent otherwise you could crush them.
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Re: Disc Vs Rim Braking System

Postby Comedian » Thu May 04, 2017 2:44 pm

jacks1071 wrote:Magura used to make a hydraulic rim brake that'd out brake any modern disc in the dry.

Only problem was the rims had to be really decent otherwise you could crush them.
Magura still make hydraulic disc brakes. They are popular on electric bikes as they help pull up the extra weight of the bike with minimal effort. As is the way, when they are working they are excellent.. The rest of the time - not so much. So far, in the 20 months we've owned our electric bike, I'd say the brakes have been either working sub optimally, or in the workshop being fixed for 5 of those months. Will be interesting when they get some age on them... :cry:

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Re: Disc Vs Rim Braking System

Postby waynohh » Fri May 05, 2017 11:48 am

The disc bike I'm building now is around 900g and $800 penalty over the equivalent road version with equivalent wheels.

Could have saved some weight by getting a post mount frame or spent a ton of extra cash for flat mount calipers.


Rival 22
2370g
$660-690

Rival 1x Hydro
2670g
$990 - with apex 1x cranks and post mount calipers

Rival 22 Hydro
2970g
$ No idea


Road frame
1500g
$550

Flat mount disc frame
1550g
$720


Skewers
150g
$0 with wheels

Thru Axles
180g
+$45

TA hubs are generally slightly lighter, but then the extra hub material for mounting discs adds weight again.


Example disc extras:

AVID Bleed Kit
+$60

Shimano RT81 Rotors
+280g
+$80

Shimano SM-MA Disc Adapters
+100g
+$45

Shimano HB20 Lockring for 15mm thru axle
+20g
+$20


Total:
Road with Rival 22 - 7.3Kg, $2500
Disc with Rival 1x - 8.2Kg, $3300

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biker jk
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Re: Disc Vs Rim Braking System

Postby biker jk » Fri May 05, 2017 12:08 pm

waynohh wrote:The disc bike I'm building now is around 900g and $800 penalty over the equivalent road version with equivalent wheels.

Could have saved some weight by getting a post mount frame or spent a ton of extra cash for flat mount calipers.


Rival 22
2370g
$660-690

Rival 1x Hydro
2670g
$990 - with apex 1x cranks and post mount calipers

Rival 22 Hydro
2970g
$ No idea


Road frame
1500g
$550

Flat mount disc frame
1550g
$720


Skewers
150g
$0 with wheels

Thru Axles
180g
+$45

TA hubs are generally slightly lighter, but then the extra hub material for mounting discs adds weight again.


Example disc extras:

AVID Bleed Kit
+$60

Shimano RT81 Rotors
+280g
+$80

Shimano SM-MA Disc Adapters
+100g
+$45

Shimano HB20 Lockring for 15mm thru axle
+20g
+$20


Total:
Road with Rival 22 - 7.3Kg, $2500
Disc with Rival 1x - 8.2Kg, $3300
What are the respective wheelsets?

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Re: Disc Vs Rim Braking System

Postby MichaelB » Fri May 05, 2017 12:19 pm

waynohh wrote:The disc bike I'm building now is around 900g and $800 penalty over the equivalent road version with equivalent wheels.

....

Example disc extras:

....
Don't forget :

Wire mesh gloves - them discs are knives !!!

Extra bandages, Dettol, wire brush and needle and thread for the injuries you'll cause, as remember, those discs are knives !!

Good lawyer to defend you in court for assault with a deadly weapon !!

Health insurance - them discs are knives.


But at least you'll have brakes that work brilliantly in all weather !! :mrgreen: :mrgreen:

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Re: Disc Vs Rim Braking System

Postby waynohh » Fri May 05, 2017 1:44 pm

biker jk wrote: What are the respective wheelsets?
The wheels I have are 30mm x 25mm on DT350 SP Centrelock hubs.
I didn't look very hard but the equivalent rim brake versions, just that they were in the ballpark.

Looking closer:
Disc ver - 1560g - $905
Rim ver - 1450g - $885
https://www.aliexpress.com/store/produc ... 0.0.0XOuyY
https://www.aliexpress.com/store/produc ... 0.0.ckfnC4
The thing that sucks with these wheels is the inner bead lock pictured in the rim profile is non-existant in the actual rim, I will try fixing that with bonty rim strips.

About 60g of that will be from spoke count and lacing pattern, 30g in hubs, and the rest possibly from no inner spoke holes.

DT350 SP Rim Front - 110g
DT350 SP Centrelock Disc 15mm Front - 136g
DT350 SP Rim Rear - 264g
DT350 SP Centrelock Disc 12mm TA Rear - 267g
https://www.dtswiss.com/Components/Hubs ... ghtpull-FW
https://www.dtswiss.com/Components/Hubs ... pull-db-FW
https://www.dtswiss.com/Components/Hubs ... ghtpull-RW
https://www.dtswiss.com/Components/Hubs ... pull-db-RW

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Re: Disc Vs Rim Braking System

Postby jacks1071 » Mon May 08, 2017 4:25 pm

Comedian wrote:
jacks1071 wrote:Magura used to make a hydraulic rim brake that'd out brake any modern disc in the dry.

Only problem was the rims had to be really decent otherwise you could crush them.
Magura still make hydraulic disc brakes. They are popular on electric bikes as they help pull up the extra weight of the bike with minimal effort. As is the way, when they are working they are excellent.. The rest of the time - not so much. So far, in the 20 months we've owned our electric bike, I'd say the brakes have been either working sub optimally, or in the workshop being fixed for 5 of those months. Will be interesting when they get some age on them... :cry:
Might need to put seals through them?
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Re: Disc Vs Rim Braking System

Postby Comedian » Tue May 09, 2017 12:56 pm

jacks1071 wrote:
Comedian wrote:
jacks1071 wrote:Magura used to make a hydraulic rim brake that'd out brake any modern disc in the dry.

Only problem was the rims had to be really decent otherwise you could crush them.
Magura still make hydraulic disc brakes. They are popular on electric bikes as they help pull up the extra weight of the bike with minimal effort. As is the way, when they are working they are excellent.. The rest of the time - not so much. So far, in the 20 months we've owned our electric bike, I'd say the brakes have been either working sub optimally, or in the workshop being fixed for 5 of those months. Will be interesting when they get some age on them... :cry:
Might need to put seals through them?
So, the rear was replaced under warranty (bike off the road for three weeks). Now, as mentioned you can pull the lever to the bar. The shop who did it under warranty said it will need bleeding, as they all do after 6-8 weeks so bring it in. $150 for the warranty repair, and now... who knows.

The Alfine rear brakes on my hybrid have no retardation and squeal. No time ATM so put it into the LBS thinking "I bet it will be seals... and no parts". Today I get the call... yes - seals gone. No seals available as part ever. You’ll have to replace the whole caliper. But – they aren’t sold separately, so Alfine Calipers can only be bought as a whole unit. But – there aren’t any in the country. Maybe they will be available in a few weeks. Maybe not. The alternative is a shimano generic caliper which is available now. Afterwards, I’ll have different pads front to rear. Yeah sure...

So tomorrow I'll be riding the MTB. I wonder if the back brake will be dragging.. I really wish all the pro disc people would come around and help me keep these darn things on the road. But they never do and they keep assuring that when all the road bikes have hydraulic discs we will have new standard of low maintenance... :roll:

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Re: Disc Vs Rim Braking System

Postby jacks1071 » Tue May 09, 2017 3:21 pm

Comedian wrote:
jacks1071 wrote:
Comedian wrote: Magura still make hydraulic disc brakes. They are popular on electric bikes as they help pull up the extra weight of the bike with minimal effort. As is the way, when they are working they are excellent.. The rest of the time - not so much. So far, in the 20 months we've owned our electric bike, I'd say the brakes have been either working sub optimally, or in the workshop being fixed for 5 of those months. Will be interesting when they get some age on them... :cry:
Might need to put seals through them?
So, the rear was replaced under warranty (bike off the road for three weeks). Now, as mentioned you can pull the lever to the bar. The shop who did it under warranty said it will need bleeding, as they all do after 6-8 weeks so bring it in. $150 for the warranty repair, and now... who knows.

The Alfine rear brakes on my hybrid have no retardation and squeal. No time ATM so put it into the LBS thinking "I bet it will be seals... and no parts". Today I get the call... yes - seals gone. No seals available as part ever. You’ll have to replace the whole caliper. But – they aren’t sold separately, so Alfine Calipers can only be bought as a whole unit. But – there aren’t any in the country. Maybe they will be available in a few weeks. Maybe not. The alternative is a shimano generic caliper which is available now. Afterwards, I’ll have different pads front to rear. Yeah sure...

So tomorrow I'll be riding the MTB. I wonder if the back brake will be dragging.. I really wish all the pro disc people would come around and help me keep these darn things on the road. But they never do and they keep assuring that when all the road bikes have hydraulic discs we will have new standard of low maintenance... :roll:
You can't beat cables for reliability or low maintenance.

I've found disc brakes that use a mineral based oil and very reliable. Those that use dot3/4 brake fluid much less so as in they seem to require more maintenance in the long term and brake fluid is nasty stuff on paint.

They are simple enough things though, if air is getting in the system you've got a leak somewhere, there isn't a real lot to them.
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Re: Disc Vs Rim Braking System

Postby Duck! » Tue May 09, 2017 7:22 pm

Comedian wrote:he alternative is a shimano generic caliper which is available now. Afterwards, I’ll have different pads front to rear. Yeah sure...
Get a caliper from the extensive selection that uses the same pads as the Alfine.....
I had a thought, but it got run over as it crossed my mind.

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Re: Disc Vs Rim Braking System

Postby singlespeedscott » Wed May 10, 2017 11:27 am

Well Campagnolo is in the game now. The end is nigh :)

https://cyclingtips.com/2017/05/campagn ... groupsets/

At least they went to Magura to get it right
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Re: Disc Vs Rim Braking System

Postby biker jk » Wed May 10, 2017 2:02 pm

singlespeedscott wrote:Well Campagnolo is in the game now. The end is nigh :)

https://cyclingtips.com/2017/05/campagn ... groupsets/

At least they went to Magura to get it right
This is interesting regarding the weight of the disc brake groupsets and wheels.

For a Super Record EPS DB groupset and Bora One 35 DB tubulars, for example, the penalty — all requisite components included — is a whopping 9g. For a Record DB mechanical groupset and Shamal Ultra DB climbers, the difference is just 78g. And for a Potenza DB disc groupset and Zonda DB wheels (which were introduced last year), you’d be tacking on an extra 200g.

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Re: Disc Vs Rim Braking System

Postby Comedian » Thu May 11, 2017 2:33 pm

Duck! wrote:
Comedian wrote:he alternative is a shimano generic caliper which is available now. Afterwards, I’ll have different pads front to rear. Yeah sure...
Get a caliper from the extensive selection that uses the same pads as the Alfine.....
So, I queried and apparently the new alfine pads are different too. So, even if I did get another alfine, it would have different pads to the alfine on the front. Unless I changed both the front and the back, which are not of course available and nor is there any idea when they might be available. So, either way I'll have something different.

It turns out I'm going to have plenty of time to contemplate this, as the Alfine 8 speed hub needs a seal replaced. I haven't found out whether there will be parts for that, but I'm not getting my hopes up.

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Re: Disc Vs Rim Braking System

Postby Duck! » Thu May 11, 2017 6:50 pm

Neither old nor new Alfine will be using unique pads. The new Alfine pads are backward-compatible with the old calipers I am rather certain. So my comment stands - use a different caliper from the extensive selection that does use the same pads. It's not rocket surgery.
I had a thought, but it got run over as it crossed my mind.

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Re: Disc Vs Rim Braking System

Postby andrewjcw » Thu May 11, 2017 8:49 pm

https://www.youtube.com/watch?v=FY6btAPsbsk

Bikeradar discussion about the future of road cycling and how disc brakes are shaking things up.
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Re: Disc Vs Rim Braking System

Postby fat and old » Fri May 12, 2017 7:39 am

singlespeedscott wrote:Well Campagnolo is in the game now. The end is nigh :)
And the pro-peleton complaints will go down. Way down.

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Re: Disc Vs Rim Braking System

Postby Mulger bill » Fri May 12, 2017 9:16 pm

fat and old wrote:
singlespeedscott wrote:Well Campagnolo is in the game now. The end is nigh :)
And the pro-peleton complaints will go down. Way down.
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Re: Disc Vs Rim Braking System

Postby Steve_ » Sun Jun 11, 2017 10:41 pm

Anyone with disc brakes on their roadie experience squealing brakes?

That would drive me nuts. Would almost rather deal with not being able to stop...

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Re: Disc Vs Rim Braking System

Postby Patt0 » Mon Jun 12, 2017 5:49 am

Steve_ wrote:Anyone with disc brakes on their roadie experience squealing brakes?

That would drive me nuts. Would almost rather deal with not being able to stop...
Yes. for a couple of stops after I clean the discs. I dont clean them any more. Each to their own.
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Re: Disc Vs Rim Braking System

Postby trailgumby » Mon Jun 12, 2017 11:29 am

Patt0 wrote:
Steve_ wrote:Anyone with disc brakes on their roadie experience squealing brakes?

That would drive me nuts. Would almost rather deal with not being able to stop...
Yes. for a couple of stops after I clean the discs. I dont clean them any more. Each to their own.
In the wet a bit. Not a big issue.

If the pads are contaminated, a lot. But then you have very big issues, such as not being able to stop. Time to toss the pads and fit new ones, AFTER you clean the rotors with disc brake cleaner and a new clean rag.

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Re: Disc Vs Rim Braking System

Postby Duck! » Mon Jun 12, 2017 12:20 pm

DON'T clean your rotors!

Brake noise is most commonly from glazed pads, especially if they're resin. Glazing is caused by overheating and baking of the pad surface, typically a result of prolongned, light dragging of the brakes. You're better off using the brakes firmly in short bursts.
I had a thought, but it got run over as it crossed my mind.

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Re: Disc Vs Rim Braking System

Postby Shelby35 » Sun Jun 18, 2017 8:17 am

Which are better resin or metal pads?

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Re: Disc Vs Rim Braking System

Postby trailgumby » Sun Jun 18, 2017 10:26 am

Duck! wrote:DON'T clean your rotors!
Sorry, Duck. This is wrong.

If your pads are contaminated, so is your rotor and whatever is on the rotor will transfer straight to the new pads. The new pads will then be useless, which will then need to follow the old ones straight into the bin. Money wasted, not to mention much frustration.

Common sources are greasy fingerprints on the rotor accidentally placed when working on the bike, overspray from spray lubricants used on the pedals, overspray from Mr Sheen or ArmourAll used on the frame, leak or drip of brake fluid when bleeding brakes (wheels should really be removed when doing this though). Sometimes, but not often, over-exuberant application of chain lube.

In each case it gets on the rotor first and is picked up by the pads on the first application of the brakes. Unless you clean the rotors first, it is too late - the pads are unrecoverable. They will howl like a banshee and not slow you down.

Cleaning the rotors does very little to diminish braking effectiveness. Any loss, especially after replacing pads, is quickly recovered after a few high-force applications of the brakes.

Cleaning your rotors after servicing your bike and before you use the brakes is a low risk preventive measure.

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