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

[rkelsen]

The same conditions didn't appear to be a problem for the Specialized Disc Crux which is also a disc braked road bike.

Because they're cable operated, not hydraulic.

[trailgumby]

I've seen those minimalist rotors and thought "no thanks " mainly because I was concerned about fork flutter and lack of brake track area ... although I hadn;t written them off completely. I have now, though

Looking at the photo on that guy's bikerumour thread, that' s clearly gone way, way over the top on heat overload. I'm very surprised actually that he didn't suffer noticeable brake drag from fluid expansion - surely that should have tipped him off that he was starting to get into problem territory.

+1 for not riding your brakes on any system: rim, cable disc or hydro disc.

I have tried a 185mm front diameter disc on my very first commuter, which had Hayes Nines. I found them very sudden - either on or off - with poor modulation. Even with sticky 32mm Conti mtb slicks I found the experience nerve-wracking in the wet and I worried about losing the front. So I'm kind of going when the roadie guys from the OEMs are going "you need 185mm rotors on road bikes".

Maybe the suddenness was down to the Nines (which were known for it) rather than the rotor size, or possibly the crap ergonomics which forced you to use two fingers because the levers were too long, but I have plenty of power and modulation from my 160mm XT hydros, even the 2006 year model on the current commuter (which, incidentally, those TRP calipers strongly resemble).

Maybe they need bigger rotors because of the reduced leverage available from the hoods on road bikes?

[Nate]

So as a 100kg+ rider on a disc brake road bike I made myself, who enjoys travelling fast down a steep descent, I reckon I can weigh in on the topic.

superb post - much appreciated!

[jasonc]

So as a 100kg+ rider on a disc brake road bike I made myself, who enjoys travelling fast down a steep descent, I reckon I can weigh in on the topic.

superb post - much appreciated!

amen. that's what this forum is all about.

[MichaelB]

TRP Parabox now installed !

First test ride tonight, but no hills yet !

Overall weight difference between the BB7 setup and the Parabox was a PALTRY + 19g.

840g removed and 859g added. One happy camper indeed

[Nobody]

CX bikes are the same as road bikes... Not Mtb's.

Maybe or now, but 135mm hub spacing is apparently on the way.

Much as we love the idea of disc brakes on the road, what's yet to be determined long-term is the rear hub spacing. Volagi have decided to stick with the standard 130mm dimension but insider rumblings suggest the industry will ultimately settle on the current 135mm disc hub standard instead. Whether or not this poses an issue for early adopters remains to be seen but it's definitely something to keep in mind.

http://www.bikeradar.com/gear/category/ ... o-11-45106

Currently the hubs are available in 135mm and 142x12 for mountain bike frames, but Russell is looking at road bikes too. Although his opinion is that road bikes will adopt 135mm spacing soon.

"I'm very much a proponent of discs on all bikes, and am actually riding a Specialized Crux with BB7s right now, with my hubset," he says. "That said, I don't intend at this point to have a 130mm disc rear hub, but rather a 135mm. I'm betting that is where we end up once the 130/135 choice is made. And heck, I can interchange that wheel from the Crux to my Cannondale Flash 29er with just a cogset swap. But if it looks like frame manufacturers decide on the 130mm spacing for disc road wheels then I'll support it. It's pretty easy to do."

http://road.cc/content/news/52734-kappi ... th-freehub

[MichaelB]

Just did another ride last night (hills again), and the system performed faultlessly.

The fisrt hills ride went well, and I used Old Belair Rd as the test descent for some hard braking. It's about 2km (AT) 9.6% with a couple of really tight corners, and a dead stop for a roundabout. Avg descent speed is often over 50km/hr.

Had to brake more than usual due to traffic, so was a good test of having to 'ride' the brakes more than you normally would.

At the bottom of the hill, I quickly stopped, and had a feel of what the rotor and caliper temps were. Disc surface was as expected, damn hot. The disc spider was about air temp, and the caliper body bugger all different, but a bit warmer, certainly not hot at all.

Only a short descent, but still a good indication, that it's performing well.

[WyvernRH]

So as a 100kg+ rider on a disc brake road bike I made myself, who enjoys travelling fast down a steep descent, I reckon I can weigh in on the topic. I've also had a decade or two in motorcycle racing and had the first disc braked MTB in the national series in Australia, so I've got some history.<snip>
Anyhoo, the moral of the story is: Use the rotor specced for the system. That is not the place to save weight. Just ask Brembo.

Excellent post! I have zero experience with bicycle discs on road (I can lock the front wheel with my 105 dual pivots so why do I need more complexity? ) but I spent a lot of time tinkering with disk brakes on racing motorcycles in the 70's and 80's and can assure you that the writer has it dead right on rotor size, mass and material to dissipate the heat. Boiling brake fluid (early Honda disks) at 120mph is not something I want to experience again. Multi pad calipers on cross drilled cast iron (Brembo!) was always best. I like the look of the set in the last picture.

One point I am interested in though is bicycle rotors liability to damage. They always seem very lightweight to me (especially the ones composed mainly of air). If you go down in a crash on the road (drop the bike in he shed) will they bend? Can they be straightened easily? How hard is it to replace the wheel after fixing a puncture? I know wheel replacement can be a bitch with some makes of motorcycle caliper, especially if some silly person grabs the brake lever while the wheel is out of the bike (who me? )

So, how long til someone comes up with a twin rotor front system for bicycles, or am I behind the times?

Cheers
Richard

[MichaelB]

One point I am interested in though is bicycle rotors liability to damage. They always seem very lightweight to me (especially the ones composed mainly of air). If you go down in a crash on the road (drop the bike in he shed) will they bend?

Hope to avoid finding out !! The common sense thing that applies, if they get enough of a knock in the wrong spot, then they will move accordingly. Chances are pretty slim though.

Not enough to use it as a reason to stick with Rim brakes.

Can they be straightened easily?

Haven't had to, but you can get a tool. I suspect that it's similar to rim straightening, but may be a bit more fiddly ?

How hard is it to replace the wheel after fixing a puncture? I know wheel replacement can be a bitch with some makes of motorcycle caliper, especially if some silly person grabs the brake lever while the wheel is out of the bike (who me? )

No difference whatsoever. Point re squeezing lever is an issue with the Hydo ones only, not Mechanical ones such as BB7.
Haven't done that yet either (squeezing lever that is ...)

So, how long til someone comes up with a twin rotor front system for bicycles, or am I behind the times?

Cheers
Richard

Focus did that as part of Project 6.8 (which is linked earlier in this thread). May take some time to catch on though. Lets get past the into of SRAM's Road disc groupset first

[trailgumby]

Disc rotors will bend, but you learn to avoid bumping them on things so it becomes unconscious habit, just like never lying your bike down on its right side so you don't bend the derailleur hanger. It is very rare to bend one in a prang. I have had one warp a little from heat build-up and then getting quenched in a stream, but al lit did was lightly brush the pad which was easily fixed with a couple of shifting spanners before the next ride.



To remove and replace wheels is relatively easy, probably even less complex than with rim brakes, and yes, you make sure you don't bump the lever while the disc is out.

If you do make a mistake, though, the insertion of a tyre lever is usually enough to re-space the pads so you can get the wheel back in, and then you just pump the lever until you get them engaging at the right point (lever parallel to bar/grips on a mtb) again.

Just make dead sure you don't put any greasy fingerprints on your disc or pads. Your brake effectiveness will go down by two thirds and they will start making the most horrendous screech. If this happens, throw your pads away, clean the rotor with automotive brake cleaner, and start over.

[MattyK]

More to the market: http://www.bikeradar.com/news/article/f ... look-33232

[MichaelB]

More to the market: http://www.bikeradar.com/news/article/f ... look-33232

Expensive for what they are. To me, the Volagi Liscio looks like a much more polished package for similar $$

[Crittski]

http://www.bikerumor.com/2012/02/23/dis ... ut-wheels/

Interesting industry discussion about road wheels with disc brakes

I wonder whyVolagi went with 130mm rear hub spacing, and whether they will stick with it...

[jasonc]

http://www.bikerumor.com/2012/02/23/disc-brakes-are-coming-to-road-bikes-but-what-about-wheels/

Interesting industry discussion about road wheels with disc brakes

I wonder whyVolagi went with 130mm rear hub spacing, and whether they will stick with it...

reading that article, they may not continue to have a choice when everyone does 135mm...

[eeksll]

hehehhe

Frame manufacturers! Just look at the current “standard” for BB systems. Nuff said.

[MichaelB]

http://www.bikerumor.com/2012/02/23/disc-brakes-are-coming-to-road-bikes-but-what-about-wheels/

Interesting industry discussion about road wheels with disc brakes

I wonder whyVolagi went with 130mm rear hub spacing, and whether they will stick with it...

Whilst there aren't many, there are choices for 130mm disc brake rear.

What will probably be the bigger driver, as what the frame manufacturers do, not the hub people.

[Crittski]

Volagi have listed their carbon rim wheel set for $1895 RRP on their webstore (availability from June2012).

MichaelB - what 130mm rear hubs have you found that would go well laced up to a sub 1500g carbon wheel set? The ones that I have found are chunky heavy things...

[MichaelB]

Volagi have listed their carbon rim wheel set for $1895 RRP on their webstore (availability from June2012).

MichaelB - what 130mm rear hubs have you found that would go well laced up to a sub 1500g carbon wheel set? The ones that I have found are chunky heavy things...

The closest are the Velocity ones, but you'd be struggling to get to 1500g for a 32 or 28 spoke setup.

I looked at using same hubs as Crawf, but they were 135mm, so not what you are after.

The available 130mm disc rears tend to be expensive and heavy atm

[toolonglegs]

Ha... my wife just peered over my shoulder "what's up with you, some middle age dude's are looking at big plastic breasts on the web... but your just looking at plastic bike pron!...not that I mind, I prefer it that way" .
Hey at least it is French pron ....

If it had hydro's it would be yummy!.

[Crittski]

Lol, disc brake on a fixie...

http://manilafixedgear.blogspot.com.au/ ... -bike.html

[zero]

gotta laff at fixie brake transmitted through chain. nice showbike yes, but doesn't buy any protection against the 2 usual reasons fixies fail to stop.

[Crittski]

Some new options from Shimano, Cross and Road mechanical disc brakes...

http://velonews.competitor.com/2012/02/ ... ore_207632

[MichaelB]

Some new options from Shimano, Cross and Road mechanical disc brakes...

http://velonews.competitor.com/2012/02/ ... ore_207632

I wonder what the "30% performance increase " over prior mech disc brakes actually means.

whilst the profile is 20% smaller, (I can sort of see it height wise), it still looks very wide, which for inboard mounted rear calipers such as on the Volagi, they can be an issue for buggers with big hoofs.

I gotta say, they look UGLY though. Wonder what the weight is compared to the BB7 though ?

[Nobody]

I wonder what the "30% performance increase " over prior mech disc brakes actually means.

It probably means their previous cable brakes weren't very good if they can improve them by that much. Considering the ones I've tried in the past on a $600 MTB, I'd say they could improve them a lot more than that.

[toolonglegs]

That's a bit boring shimano!... I will be sticking with canti's for next winter me thinks.