Adding a front disc to a road bike !! And Now Hydro!

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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MichaelB » Tue Jun 18, 2013 1:41 pm

rkelsen wrote:
barefoot wrote:[1] My day job is testing automotive disc brakes. I am yet to see slotted or drilled car rotors improve anything other than bling factor. All they do is cause pad wear, as the edges of the slots shave the surface off the pads.

Right. Next you'll tell me that the spoiler on my boot doesn't help me go faster in traffic. :roll:



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by BNA » Tue Jun 18, 2013 4:42 pm

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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby barefoot » Tue Jun 18, 2013 4:42 pm

Ross wrote:
barefoot wrote:[1] My day job is testing automotive disc brakes. I am yet to see slotted or drilled car rotors improve anything other than bling factor. All they do is cause pad wear, as the edges of the slots shave the surface off the pads. We saw in a recently discussed article, disc brakes in CX failing in mud due to excessive pad wear. I reckon this was largely due to abrasive debris (ie mud) getting into the rotor slots, and getting into the brake contact area that way. I'd like to get rid of the slots. On principle, I bought a set of Avid "solid sweep" un-slotted rotors, but haven't fitted them yet... damn they're heavy with all that steel where the slots used to be!


I changed the disc rotors to slotted (not drilled) on a previous car I had and could notice a big difference in the braking. I can see your point about the brake pads wearing (I didn't have the car long enough or do enough miles to tell) but I guess that's the price you pay for better performance.

Many performance type cars such as V8 Supercars run a slotted rotor, I'm sure they have tested them and compared them to non-slotted rotors. Obviously V8 Supercars have different braking requirements than a road bicycle.


Did you change anything other than the rotors? I've seen that happen a few times - people go from a set of cheap and nasty pads on plain rotors to higher-friction pads on slotted rotors, and attribute the braking improvement to the rotors :-D

Not meaning to start a pissing competition, but I've got about $6m worth of brake dynos humming away in the room next door. When I've tested plain and slotted rotors back to back with the same friction, I've not seen a difference. Caveat: under normal test conditions.

By "normal test conditions", I mean a standard performance test procedure that includes a "fade" sequence of 15 moderate stops from 100 km/h to zero, back to back. Brake temperatures up around 500°C. Now, rotors don't start glowing until upward of 600°, and I know race cars frequently get theirs lit up into the cherry-ish colour range, upward of 700°C. We don't test at those temperatures very often, because honestly, it's just not relevant. I'll cheerfully admit ignorance of that end of brake performance, where slots may well make a measurable difference. It's the only explanation I can make as to why they, and other serious players who really ought to know [1], persist with slotted rotors.

However... I'm yet to see a bicycle disc rotor glowing red hot either, so I'll reclaim some relevance.

One particular local car builder, at one stage, wanted to offer slotted rotors as a dealer option for their wings-and-blings models. Since it was a new car option, they had to prove that the brake performance was adequate to meet ADR. Rather than pay for a comprehensive ADR test, they went for a quicker "equivalence" test - where they just had to show that the optional brake system performed within 15% of the standard system throughout the test. No problem, because everybody close to the industry knows that slots make no difference (at least under the of conditions in an ADR equivalence test). Everybody was surprised when the slotted rotor REDUCED the fade friction by more than 15%. Many modern friction materials incorporate the products of their own chemical decomposition under temperature as part of the friction couple. By scraping this combusted layer off the surface of the pad, the slots were removing a vital part of the material. Wearing the pads unnecessarily fast AND reducing performance... but they look sweeeeet ;-) . That dealer option didn't go ahead.

Anyway, that's an unusual result. Like I said, most often, the only discernible difference on dyno is the wear rate.

tim

[1] as opposed to certain local street-racer-spec modified taxi builders, who fit slotted rotors to their vehicles purely for aesthetics, knowing full well that it gives no performance benefit. I've heard snippets of discussion between engineering and marketing people from these places...
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MichaelB » Tue Jun 18, 2013 5:38 pm

barefoot wrote: .... as opposed to certain local street-racer-spec modified taxi builders, who fit slotted rotors to their vehicles purely for aesthetics, knowing full well that it gives no performance benefit. I've heard snippets of discussion between engineering and marketing people from these places...


Stop it. I don't believe you. marketing people would NEVER do that. :? Imagine if they started stooping to spruiking 'performance' bits for transport contraptions that provided no benefit for the user yet claimed all sorts of advantages !!!

NEVER I SAY !!!! :| :roll: :lol:
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby Nobody » Tue Jun 18, 2013 5:44 pm

MichaelB wrote:
barefoot wrote: .... as opposed to certain local street-racer-spec modified taxi builders, who fit slotted rotors to their vehicles purely for aesthetics, knowing full well that it gives no performance benefit. I've heard snippets of discussion between engineering and marketing people from these places...


Stop it. I don't believe you. marketing people would NEVER do that. :? Imagine if they started stooping to spruiking 'performance' bits for transport contraptions that provided no benefit for the user yet claimed all sorts of advantages !!!

NEVER I SAY !!!! :| :roll: :lol:
:lol: Don't get me started on the parallels with bikes...
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby Blakeylonger » Tue Jun 18, 2013 5:51 pm

barefoot wrote:However... I'm yet to see a bicycle disc rotor glowing red hot either, so I'll reclaim some relevance.


Search youtube for the TRP testing videos of the HyRd caliper.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby Nobody » Tue Jun 18, 2013 6:54 pm

Blakeylonger wrote:
barefoot wrote:However... I'm yet to see a bicycle disc rotor glowing red hot either, so I'll reclaim some relevance.


Search youtube for the TRP testing videos of the HyRd caliper.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby lock_ » Wed Jun 19, 2013 8:18 am

^nice, always loved watching Le Mans at night with the glowing discs.

There's an industry press camp happening over in Utah ATM, Orbea's latest showed up.
Image

http://reviews.roadbikereview.com/bike-presscamp-2013-live-blog

Seems Ridley didn't see the need to bring along any non-disc CX bikes.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby lock_ » Wed Jun 19, 2013 1:50 pm

Tsk, tsk, naughty Orbea/RoadBikeReview. Sure we've all seen the new Ultegra Di2 11 speed deraillers and shifters, but to let this slip out before the Shimano announcement. I may be looking a little too close at those shifters/callipers, curious as to what others make of it.

http://reviews.roadbikereview.com/orbea-launches-avant-endurance-bike#slider-pro-3-10

Image
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby jasonc » Wed Jun 19, 2013 1:58 pm

sram red 22 shifters, only 10 speed cassette too...
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MichaelB » Wed Jun 19, 2013 2:48 pm

jasonc wrote:sram red 22 shifters, only 10 speed cassette too...


Are you talking about the SRAM Red setup on the Orbea ?

I like it, it looks good, as did the Bianchi XR2. Mind you, the pics of the Orbea Avant with rear rack, mudguards and what looks like Zipp 303 is a bit odd .....


But yep, looks like a slip showing the 6800 Di2 with discs :lol:
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby barefoot » Wed Jun 19, 2013 3:01 pm



*sigh*

TFA wrote:Billed as a bike that will, “Take you from here to there on any road anywhere,” the Avant boasts...
...
Other features include ... tire clearance up to 28mm...


Let's see them taking one of them, on 28mm road tyres, from here to there on this particular iteration of "any road":
Image

I don't understand the obsession with artificially limiting tyre clearance on road bikes.

What do they gain by putting a bit of carbon in the way of fitting bigger tyres? It's not like they're limited to what fits through the brake caliper anymore.

(And no, mine isn't a CX bike. I gave it a low BB and fairly short chainstays, like a road bike. Yes, it can fit CX tyres, because... why shouldn't it?)

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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby cobba » Wed Jun 19, 2013 3:18 pm

lock_ wrote:I may be looking a little too close at those shifters/callipers, curious as to what others make of it.


The photo of the red/white/black bike that you've posted shows Shimano calipers & rotors.

Looks like they could be any of the following.

Calipers = BR-M666 / BR-M675 / BR-M785 / BR-M985 / BR-M987

Rotors = SM-RT76 / SM-RT79 / SM-RT81 / SM-RT86 / SM-RT98 / SM-RT99
Last edited by cobba on Wed Jun 19, 2013 4:16 pm, edited 1 time in total.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MichaelB » Wed Jun 19, 2013 3:45 pm

I reckon they are hydro, as that is what is ring released soon.

The mech calipers have a different profile
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby cobba » Wed Jun 19, 2013 3:56 pm

MichaelB wrote:The mech calipers have a different profile


Mechanical calipers don't use Ice-Tech pads either, the brakes in the photo look to have Ice-Tech pads.

http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/disc_brakes/deore_xt.html
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby lock_ » Wed Jun 19, 2013 4:29 pm

Must be hydro, otherwise why the different shifter. It is quite a bit larger than the conventional Di2 shifters and bares some similarity to the only other sighting I know of.

cobba wrote:Looks like they could be any of the following.

Calipers = BR-M785 / BR-M985 / BR-M987

Rotors = SM-RT76 / SM-RT79 / SM-RT81 / SM-RT86 / SM-RT98 / SM-RT99


Does look similar, like I can see some of those cooling fins, but it is pretty hard to tell with such an image. Guess I just assumed that they'd come up with a road-specific calliper, maybe they tested the MTB designs in road situations and figured they were fine for a v1.0. Possibly saving R&D $$$ on a product that may not gain widespread acceptance.

barefoot wrote:Let's see them taking one of them, on 28mm road tyres, from here to there on this particular iteration of "any road":

I see no road :wink: .

But seriously, more clearance can start to look a little odd and the aero-weenies would probably be onto you... Personally I'd be loath to switch tires based on intended rides, so my roadies are largely restricted to paved roads, with the occasional off road adventure which often ends in a 'this just isn't working' realisation.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby lock_ » Thu Jun 20, 2013 1:34 pm

MichaelB wrote:But yep, looks like a slip showing the 6800 Di2 with discs :lol:


And now we have a broken link :lol: . I have a saved copy, but might just let this one go down the memory hole.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MichaelB » Thu Jun 20, 2013 2:41 pm

lock_ wrote:
MichaelB wrote:But yep, looks like a slip showing the 6800 Di2 with discs :lol:


And now we have a broken link :lol: . I have a saved copy, but might just let this one go down the memory hole.


Naughty Orbea !!!!

No new Shimano groupsets for YOU !! :twisted:
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby lock_ » Thu Jun 20, 2013 11:14 pm

Few catalogue pictures of the 6870 Ultegra Di2 and the hydro disc brake rotor, pad and calliper.

Calliper gets the designation of BR-R785, according to my understanding this puts it at an Ultegra type level. This is fine by me, hate to think what price a DA Hydraulic Di2 groupset would go for. The hydraulic stuff doesn't seem branded to any spec level (eg; Ultegra or DA), guess they didn't want people to shy away from mix 'n matching.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MichaelB » Fri Jun 21, 2013 7:43 am

lock_ wrote:Few catalogue pictures of the 6870 Ultegra Di2 and the hydro disc brake rotor, pad and calliper.

Calliper gets the designation of BR-R785, according to my understanding this puts it at an Ultegra type level. This is fine by me, hate to think what price a DA Hydraulic Di2 groupset would go for. The hydraulic stuff doesn't seem branded to any spec level (eg; Ultegra or DA), guess they didn't want people to shy away from mix 'n matching.


Those pics line up nicely with the Orbea pic and the info that I have managed to glean as well.

It will be interesting to see what the pad spec is.

At the moment., only metallic pads have the cooling fins, so curious as to what spec the pad material in the road version is. I am presuming the piston size is the same as the current 785 caliper is XT level in the MTB range

Image

Image


One thing I noticed with the SRAM 22 Red calipers is that the piston sizes are 19mm front and 18mm rear. I wonder was the m/cyl sizwes are and the reasoning for going to the smaller pistons, and wonder if the Shimano 785 calipers retain the 22mm piston size ?

I think that there may be a DA level version, but that will be in next years release.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby Duck! » Fri Jun 21, 2013 9:13 am

MichaelB wrote:
At the moment., only metallic pads have the cooling fins....

Incorrect, cooling fins are offered on both resin and metallic pads. :wink:
I had a thought, but it got run over as it crossed my mind.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby __PG__ » Fri Jun 21, 2013 10:04 am

I was talking to a staff member at Cycles Galleria in Melbourne a few days ago about the imminent Shimano hydraulic road groupset. He said Shimano were looking at making handlebars with inbuilt reservoirs, but decided that they didn't want to have to make lots of different sizes so they have left the reservoir in the shifter body, for now.
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby __PG__ » Fri Jun 21, 2013 10:08 am

lock_ wrote:Tsk, tsk, naughty Orbea/RoadBikeReview. Sure we've all seen the new Ultegra Di2 11 speed deraillers and shifters, but to let this slip out before the Shimano announcement. I may be looking a little too close at those shifters/callipers, curious as to what others make of it.

http://reviews.roadbikereview.com/orbea-launches-avant-endurance-bike#slider-pro-3-10

Image


That's exactly what I'm looking for in my next bike (except perhaps more tire clearance).
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby rkelsen » Fri Jun 21, 2013 4:18 pm

barefoot wrote:I don't understand the obsession with artificially limiting tyre clearance on road bikes.

It's because road bikes are all about aerodynamics... and road racers never really use tyres bigger than 25mm anyhow, so why should they be made to accommodate tractor tyres?
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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby barefoot » Fri Jun 21, 2013 5:00 pm

rkelsen wrote:
barefoot wrote:I don't understand the obsession with artificially limiting tyre clearance on road bikes.

It's because road bikes are all about aerodynamics... and road racers never really use tyres bigger than 25mm anyhow, so why should they be made to accommodate tractor tyres?


Because why shouldn't they?

Do you think there's an aerodynamic benefit for a 23mm tyre to be running between chainstays with 25mm clearance, as opposed to chainstays with 35mm clearance between them?

Considering these chainstays are running from a BB that's 68mm (plus external bearings) wide to a rear hub that's 130-135mm wide (plus dropout thickness)?

Is there an aerodynamic benefit for a tyre to run within 2mm of a fat bulbous fork crown, compared to running with 10mm clearance to a slimmer fork crown?

I can run skinny tyres on my bike just as easily as they can, reaping the (theoretical) aero benefits and the (real) weight benefits of having a narrow/light tyre.

But I can also run big tyres when I choose. They eliminate this possibility... for zero benefit, in my judgement.

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Re: Adding a front disc to a road bike !! And Now Hydro!

Postby MattyK » Fri Jun 21, 2013 5:05 pm

rkelsen wrote:
barefoot wrote:I don't understand the obsession with artificially limiting tyre clearance on road bikes.

It's because road bikes are all about aerodynamics... and road racers never really use tyres bigger than 25mm anyhow, so why should they be made to accommodate tractor tyres?

Because it's more aerodynamic?
Image
http://cycletechreview.com/2012/news/te ... es-part-2/
Interestingly, this fork was used by the men’s and women’s team pursuit squads; both need excellent aerodynamics. There’s no obvious reason, other than improved aerodynamics, why the women’s squad, whose members are unlikely to trouble the fork’s structural integrity, should choose it over the Pursuit fork, so we may reasonably infer from this that the design offers lower air drag, perhaps by allowing the air to pass more freely between wheel and fork legs.

Sadly, the same gap would need to be filled by any front brake acting on the rim, so the fork is unlikely to see road action any time soon. Maybe it is just waiting for a suitable disc brake.
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