Disc Vs Rim Braking System

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Duck!
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Re: Disc Vs Rim Braking System

Postby Duck! » Mon Mar 06, 2017 9:21 pm

It's not just the weight, 9000 (and older Dura-Ace) have little ball bearings on the pivots, which the cheaper ones don't get, so they work a bit smoother & the action is a bit lighter (providing the cable isn't stuffed), but the caliper geometry is the same.
Last edited by Duck! on Mon Mar 06, 2017 10:25 pm, edited 1 time in total.
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 warthog1 » Mon Mar 06, 2017 9:35 pm

Thanks Duck. I wouldn't have known that otherwise.
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Re: Disc Vs Rim Braking System

Postby Comedian » Mon Mar 27, 2017 1:46 pm

So disc bikes are starting to pop up in increasing frequency in our local bunch ride. Of particular note was one of the regulars with his new Focus with discs who came along Saturday. Bike is two weeks old.

He arrived at the start point, and there was looking, pointing, pained looks. It turns out that it had a cracked frame right next to the rear disc. It was decided that it would be Ok to ride. I didn’t get the story at that point.

I had a chance to look at it at the coffee shop after. The frame was clearly cracked, right where the edge of the disc passed through the frame. I thought “it looks like something has been drawn in and forced between the disc and the stay popping it”. About then the owner popped and confirmed my diagnosis.

It turns out that he had spotted a scrub turkey nearby and grabbed the brakes. This was fine, but the guy behind had no chance and ran into the back. Apparently in the chaos the shifter got caught between the disc and the frame. It had a big try at slicing the lever off but in the process sucked the shifter through the gap destroying it, the frame and bending the disc in the process. The owner of the bike behind didn’t get a mention so I gather he/she was OK. :o It was hoped the frame can be repaired.

So the observations from this for me.

- If you sell people bikes with very effective brakes on the premise that these brakes are very effective they will use them (as I expected – crash different). In this case he avoided a potential accident with the turkey and caused one because in road biking we sit so close that there is just no time regardless of what type of brakes you have.
- I hadn’t considered that they would suck things in between the disc and the frame and then slice them.. but there you go. Apparently the shifter was massacred. Accidents are like that.. random stuff happens.
- It seems nothing has changed in Shimano land. The guy tried to get a replacement disc. Of course no discs in the country, nobody knows when. They rang lots of shops looking for one but no one would take one off a bike for them… not falling for that..
- I really think these things should be sold with covers. If the user wants to remove the covers then fine.

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Re: Disc Vs Rim Braking System

Postby biker jk » Mon Mar 27, 2017 2:02 pm

Comedian wrote:So disc bikes are starting to pop up in increasing frequency in our local bunch ride. Of particular note was one of the regulars with his new Focus with discs who came along Saturday. Bike is two weeks old.

He arrived at the start point, and there was looking, pointing, pained looks. It turns out that it had a cracked frame right next to the rear disc. It was decided that it would be Ok to ride. I didn’t get the story at that point.

I had a chance to look at it at the coffee shop after. The frame was clearly cracked, right where the edge of the disc passed through the frame. I thought “it looks like something has been drawn in and forced between the disc and the stay popping it”. About then the owner popped and confirmed my diagnosis.

It turns out that he had spotted a scrub turkey nearby and grabbed the brakes. This was fine, but the guy behind had no chance and ran into the back. Apparently in the chaos the shifter got caught between the disc and the frame. It had a big try at slicing the lever off but in the process sucked the shifter through the gap destroying it, the frame and bending the disc in the process. The owner of the bike behind didn’t get a mention so I gather he/she was OK. :o It was hoped the frame can be repaired.

So the observations from this for me.

- If you sell people bikes with very effective brakes on the premise that these brakes are very effective they will use them (as I expected – crash different). In this case he avoided a potential accident with the turkey and caused one because in road biking we sit so close that there is just no time regardless of what type of brakes you have.
- I hadn’t considered that they would suck things in between the disc and the frame and then slice them.. but there you go. Apparently the shifter was massacred. Accidents are like that.. random stuff happens.
- It seems nothing has changed in Shimano land. The guy tried to get a replacement disc. Of course no discs in the country, nobody knows when. They rang lots of shops looking for one but no one would take one off a bike for them… not falling for that..
- I really think these things should be sold with covers. If the user wants to remove the covers then fine.
Your trolling isn't improving. :lol:

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Re: Disc Vs Rim Braking System

Postby baabaa » Mon Mar 27, 2017 2:04 pm

Scrub turkey?
Brush turkey!

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Re: Disc Vs Rim Braking System

Postby Comedian » Mon Mar 27, 2017 2:07 pm

biker jk wrote:
Comedian wrote:So disc bikes are starting to pop up in increasing frequency in our local bunch ride. Of particular note was one of the regulars with his new Focus with discs who came along Saturday. Bike is two weeks old.

He arrived at the start point, and there was looking, pointing, pained looks. It turns out that it had a cracked frame right next to the rear disc. It was decided that it would be Ok to ride. I didn’t get the story at that point.

I had a chance to look at it at the coffee shop after. The frame was clearly cracked, right where the edge of the disc passed through the frame. I thought “it looks like something has been drawn in and forced between the disc and the stay popping it”. About then the owner popped and confirmed my diagnosis.

It turns out that he had spotted a scrub turkey nearby and grabbed the brakes. This was fine, but the guy behind had no chance and ran into the back. Apparently in the chaos the shifter got caught between the disc and the frame. It had a big try at slicing the lever off but in the process sucked the shifter through the gap destroying it, the frame and bending the disc in the process. The owner of the bike behind didn’t get a mention so I gather he/she was OK. :o It was hoped the frame can be repaired.

So the observations from this for me.

- If you sell people bikes with very effective brakes on the premise that these brakes are very effective they will use them (as I expected – crash different). In this case he avoided a potential accident with the turkey and caused one because in road biking we sit so close that there is just no time regardless of what type of brakes you have.
- I hadn’t considered that they would suck things in between the disc and the frame and then slice them.. but there you go. Apparently the shifter was massacred. Accidents are like that.. random stuff happens.
- It seems nothing has changed in Shimano land. The guy tried to get a replacement disc. Of course no discs in the country, nobody knows when. They rang lots of shops looking for one but no one would take one off a bike for them… not falling for that..
- I really think these things should be sold with covers. If the user wants to remove the covers then fine.
Your trolling isn't improving. :lol:
Sure.. denial is so soothing. I did think about taking photos but there was only a cracked frame to see. I wish I'd seen the shifter..

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Re: Disc Vs Rim Braking System

Postby Comedian » Mon Mar 27, 2017 2:08 pm

baabaa wrote:Scrub turkey?
Brush turkey!
Yes, good point! :mrgreen:

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Re: Disc Vs Rim Braking System

Postby silentC » Mon Mar 27, 2017 2:19 pm

I really think these things should be sold with covers.
Absolutely! Those shifters are dangerous!
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Re: Disc Vs Rim Braking System

Postby Comedian » Mon Mar 27, 2017 3:01 pm

silentC wrote:
I really think these things should be sold with covers.
Absolutely! Those shifters are dangerous!
What about the turkeys? Cover them too? :roll:

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Re: Disc Vs Rim Braking System

Postby silentC » Mon Mar 27, 2017 3:07 pm

Turkeys are just something we all have to deal with ;)
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Re: Disc Vs Rim Braking System

Postby hamishm » Mon Mar 27, 2017 4:29 pm

Comedian wrote:- It seems nothing has changed in Shimano land. The guy tried to get a replacement disc. Of course no discs in the country, nobody knows when. They rang lots of shops looking for one but no one would take one off a bike for them… not falling for that..
What? I've seen spare rotors in my LBS. Pushys and Bikebug have them listed in stock too. :roll:

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Re: Disc Vs Rim Braking System

Postby BJL » Mon Mar 27, 2017 4:44 pm

Comedian's post about the cracked frame due to an accident has reminded me of something. I'm probably going to get flamed for this but the one thing bikes should have is brake lights. Far more effectively at indicating to those behind that you're slowing down or stopping instead of little hand gestures or shouting or in the absence of those, suddenly realizing that you're now closer to the bike in front than you were 2 seconds ago. Any reduction in reaction time should be seen as a positive thing. Shouldn't be too difficult to fit mirco-switches in the brake levers and with Di2 now common, there's a bunch of wires already so one or two more isn't going to make any difference. Only thing needed is a standard for rear lights so that they change to solid or get brighter when the brakes are applied and a common 'sense' connector is used on the lights themselves.

So yeah, flame suit now on!

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Re: Disc Vs Rim Braking System

Postby MichaelB » Mon Mar 27, 2017 6:59 pm

Really .....

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Re: Disc Vs Rim Braking System

Postby Comedian » Tue Mar 28, 2017 7:39 am

hamishm wrote:
Comedian wrote:- It seems nothing has changed in Shimano land. The guy tried to get a replacement disc. Of course no discs in the country, nobody knows when. They rang lots of shops looking for one but no one would take one off a bike for them… not falling for that..
What? I've seen spare rotors in my LBS. Pushys and Bikebug have them listed in stock too. :roll:
So I asked the owner of the bike, and he told me that they couldn't get a shimano rotor. So my mate works in an opposition bike shop.. and they got the call and refused to strip their bike. I was telling her the story and she said "Hey I heard that call come in".

Maybe you're right - the particular rotor part number for that focus might be freely available.. but the bike shop fixing it couldn't find it. I made no attempt to cross check the part numbers between several online suppliers when making the above statement. However, the bike I was looking at had a shimano rotor on the front and a non shimano rotor on the back. :roll:

It's been fascinating watching the deadly silence and denial in here from the disc supporters. It's true.. I wasn't there. The takeouts posted are my own. But what I've told you in here is what I've been told by the owner of the bike. This happened. :roll: I'm sure there is a psychological thesis in this somewhere..

Time will tell whether we see more of these freakish "who would have thought" incidents.. but I've now seen one myself (or at least the aftermath). :shock: Thankfully no one hurt.

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Re: Disc Vs Rim Braking System

Postby MichaelB » Tue Mar 28, 2017 8:05 am

Comedian wrote: ....It's been fascinating watching the deadly silence and denial in here from the disc supporters. It's true.. I wasn't there. ....
And the response is meant to be what ?

Sometimes reallry rare and random things that you could never predict happen ?

So ?


Completely aside from the 'couldn't find a spare rotor rubbish' (which points more towards a useless bike shop than anything else), what was your diatribe menat to show/prove ?

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Re: Disc Vs Rim Braking System

Postby silentC » Tue Mar 28, 2017 9:17 am

That colliding with the bike in front of you is likely to cause damage?

Meh, bikes have lots of sticky out bits that get tangled up when n>1. Anyone who has put two or more bicycles on a bike rack knows that.

It's not some sort of smoking gun.
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Re: Disc Vs Rim Braking System

Postby RobertL » Tue Mar 28, 2017 10:31 am

Comedian wrote:So disc bikes are starting to pop up in increasing frequency in our local bunch ride. Of particular note was one of the regulars with his new Focus with discs who came along Saturday. Bike is two weeks old.

He arrived at the start point, and there was looking, pointing, pained looks. It turns out that it had a cracked frame right next to the rear disc. It was decided that it would be Ok to ride. I didn’t get the story at that point.
Comedian - I was on that Lifecycle ride on Saturday! We'll have to introduce ourselves. I'll be the tall, fat guy with the red and white Malvern Star Oppy.

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Re: Disc Vs Rim Braking System

Postby bychosis » Tue Mar 28, 2017 10:39 am

My 4yo has some glue on his knee from hitting a disc rotor. Another accident. Ran up the back of a mountain bike as the other bike turned left and he couldn't stop in time. His right arm hooked over the wheel and it dragged him in as his little bike fell from under. Trip to medical decided stitches weren't necessary, but gluing and immobilising would suffice.

I'm still pro disc brakes though after riding through wet grass again on the weekend and not being able to stop afterwards until the rims dried off. I'd rather not have to ride the brakes to dry them off when it's wet.
bychosis (bahy-koh-sis): A mental disorder of delusions indicating impaired contact with a reality of no bicycles.

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Re: Disc Vs Rim Braking System

Postby hamishm » Tue Mar 28, 2017 12:03 pm

I honestly don't know how you get your shifter jammed between the disc and the frame of the bike in front. I can't even see how you would arrange that while stationary, letalone while crashing.

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Re: Disc Vs Rim Braking System

Postby Duck! » Tue Mar 28, 2017 1:32 pm

Given the points of contact, it is entirely plausible that similar damage would be inflicted with a rim-braked wheel. So you can't blame the disc brake for this either.
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 Mulger bill » Tue Mar 28, 2017 7:33 pm

Duck! wrote:Given the points of contact, it is entirely plausible that similar damage would be inflicted with a rim-braked wheel. So you can't blame the disc brake for this either.
You can when you're as myopic as you claim opposing PoVs are...
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Re: Disc Vs Rim Braking System

Postby fat and old » Wed Mar 29, 2017 1:14 pm

BJL wrote:Comedian's post about the cracked frame due to an accident has reminded me of something. I'm probably going to get flamed for this but the one thing bikes should have is brake lights. Far more effectively at indicating to those behind that you're slowing down or stopping instead of little hand gestures or shouting or in the absence of those, suddenly realizing that you're now closer to the bike in front than you were 2 seconds ago. Any reduction in reaction time should be seen as a positive thing. Shouldn't be too difficult to fit mirco-switches in the brake levers and with Di2 now common, there's a bunch of wires already so one or two more isn't going to make any difference. Only thing needed is a standard for rear lights so that they change to solid or get brighter when the brakes are applied and a common 'sense' connector is used on the lights themselves.

So yeah, flame suit now on!
Just saw this.

Whilst I actually agree...enthusiastically tbh...with the sentiments (on a general safety POV, not bunch ride specific), the downside is that then ALL bikes would be forced to have them. Retro fitting an older classic; or indeed a new Colnago Master for instance; would be a crime against cycles. I have to side with Yug Yug here. It's a bicycle. Not a Motor Vehicle.

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Re: Disc Vs Rim Braking System

Postby ironhanglider » Wed Mar 29, 2017 9:46 pm

Brake lights have been around for a long time, just not very successfully.

Typically they work from having a switch at the calliper which is operated by the action of moving the cable, closing a switch to complete a circuit.

I have also had one that was self contained as part of a tail light, and actioned by some sort of accelerometer. However no-one even noticed.

In any case brake lights only work after you have applied the brakes. Smart riders in a bunch will be looking further forward and be responding to whatever it was that caused the brakes to be applied, because there is not enough time to respond afterwards.

Cheers,

Cameron

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Re: Disc Vs Rim Braking System

Postby hamishm » Thu Mar 30, 2017 2:15 pm

BJL wrote:Shouldn't be too difficult to fit mirco-switches in the brake levers and with Di2 now common, there's a bunch of wires already so one or two more isn't going to make any difference.
There's only 2 wires in Di2 actually, it's a serial bus. In theory the brake levers and a brake light could be connected as well, but it would be a lot more wiring. And then people might expect to power their rear light from the Di2 power, except then you'd flatten your shifting quickly.

The Bontrager Flare R has an acceleremator which detects you slowing down and brightens the light. No wires required. Maybe that is 95% of the solution?

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Re: Disc Vs Rim Braking System

Postby Comedian » Thu Mar 30, 2017 6:09 pm

MichaelB wrote:
Comedian wrote: ....It's been fascinating watching the deadly silence and denial in here from the disc supporters. It's true.. I wasn't there. ....
And the response is meant to be what ?

Sometimes reallry rare and random things that you could never predict happen ?

So ?
All through this those in favour or discs have constantly maintained that there is no additional risk from disc brakes. And I've argued, that there must be additional risk because there are two additional danger points on top of the existing ones.

I've argued that roadbiking is fundamentally different to mountain biking, because (amongst other reasons) we sit so close to one another and because crashing into other riders is really quite common. The argument against this firstly to bleat "but chainrings" and when given an example of someone being hurt by a discs is to just say "that's rubbish - they don't know what happened" and stick their fingers in their ears and go "nahanahnahnah".

I've seen horrible bunch crashes in the recent past, and I've argued that discs should be covered in racing. Now I'm arguing that they should be covered by default. It would appear though that the proponents don't want this - for some selfish reason that I can't fathom. Well I think cover them, and if the owner chooses to take the cover off then the bike is banned from racing, and they have a point of contributory negligence should some other rider by hurt by their disc brake bike.
Mulger bill wrote:
Duck! wrote:Given the points of contact, it is entirely plausible that similar damage would be inflicted with a rim-braked wheel. So you can't blame the disc brake for this either.
You can when you're as myopic as you claim opposing PoVs are...
A shifter between a rim brake and a wheel? Really? :mrgreen: This is so typical of the people in this thread. Will discs really be that good for your business?? :|
bychosis wrote:My 4yo has some glue on his knee from hitting a disc rotor. Another accident. Ran up the back of a mountain bike as the other bike turned left and he couldn't stop in time. His right arm hooked over the wheel and it dragged him in as his little bike fell from under. Trip to medical decided stitches weren't necessary, but gluing and immobilising would suffice.

I'm still pro disc brakes though after riding through wet grass again on the weekend and not being able to stop afterwards until the rims dried off. I'd rather not have to ride the brakes to dry them off when it's wet.
Yup.. well looks like we're going to see more and more of these "who would have thought it" injuries in the future. Hopefully someone somewhere sues a manufacturer.
RobertL wrote:
Comedian wrote:So disc bikes are starting to pop up in increasing frequency in our local bunch ride. Of particular note was one of the regulars with his new Focus with discs who came along Saturday. Bike is two weeks old.

He arrived at the start point, and there was looking, pointing, pained looks. It turns out that it had a cracked frame right next to the rear disc. It was decided that it would be Ok to ride. I didn’t get the story at that point.
Comedian - I was on that Lifecycle ride on Saturday! We'll have to introduce ourselves. I'll be the tall, fat guy with the red and white Malvern Star Oppy.
Come up and say hello. Despite what people in here think.. I'm actually a real person, with abilities to look, learn, and logically asses risk. And I didn't make this stuff up! :mrgreen: Did you see me looking at the bike and talking to the owner?

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