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PostPosted: Tue Sep 12, 2017 2:29 pm 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
Chinese can build very nice paved roads with scenic views. They do not seem to have a standard of what is the maximum grade allowed. Some of the best roada I've been on has had grades up to almost 30%. It's a lot of fun to climb those but descending on that kind of road on rim brakes is insane. Feels like free falling almost.

I'd like to train there every day without having to be so tactical with the brakes. Or buying expensive brake pads every 4 months.

/a


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Posted: Tue Sep 12, 2017 2:29 pm 


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PostPosted: Tue Sep 12, 2017 2:45 pm 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
Lieblingsleguan wrote:
alcatraz wrote:
Lieblingsleguan wrote:
If you worry about heating up your rims to much, you shouldn't use ultralight disc rotors either. And you should go 160mm instead of 140. A SRAM Centerline X will be 102g for example.


I guess I can toast the brake pads if I go over 300 degrees but I won't overheat the rims. How is the heat supposed to transfer to the rim?

Hopefully there is a pad/disc combo out there that can take some serious heat and still have a fair amount of bite. Generic ones might be unimpressive.

I don't think I can melt the disc. 140mm is going to give me relatively poor disc brake performance yes but I think I can drag the brakes as much as I like.

/a

No you can't. You will warp the rotors Also, the braking power of a disc brake with 140mm rotors will be significantly worse than that of a rim brake.

But please, go ahead and build this bike. You have made up your mind obviously. I am looking forward to hear how this didn't turn out to be a heavy, uncomfortable, badly braking and badly handling bike.


I didn't know about the warping. First time it's been mentioned.

Thx

Warum immer so Schadenfroh? Sei lieber Froh Freund! :)

/a


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PostPosted: Tue Sep 12, 2017 3:28 pm 
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Joined: Sat Dec 29, 2007 11:35 pm
Posts: 144
Location: Denmark/Herning
alcatraz wrote:
I'm just playing with the idea. I can't afford a new bike for another year at least.

It was never my intention to annoy anyone. I understand that people who do race have to abide by the rules and don't really think out of the box.

You say poorly fitting and poorly handling. The fit can be helped by choosing a suitable size (most importantly to get the stack/head tube right). If the size is big enough to bring the base bar (still streamlined) in the right height I'll be doing ok, don't you think?

The idea that I love is that a TT bike can be made fairly light and is not restricted in it's tube profiles like all the aero bikes. The place on road and aero bikes that is still quite underdeveloped is the cockpit area. My effort is to bring aero efficiency to this area without degrading the fit too much.

My current bike has a quite extreme position already. My drops are quite close to my front wheel. I've ridden thousands of km like this and start to feel very good. My issues are with being aero and braking downhill. I'd like my next bike to improve in those areas.

I'm not racing. I'm an amateur mechanic that likes to try out some ideas and I don't like being restrained to these three categories climb/aero/tt or the UCI. I'm always riding a lot of everything on my routes so even if I did have three bikes I wouldn't have the one I needed for that particular moment. (climb/flat/descent)

I'm attempting to come closer to an efficient do-it-all bike.

/a

Edit: This idea was inspired by the build done by tririg: Liberty bike.
Image
Image

Bike would look somewhat like this 2/3 of the time.
Image


That bike - the Liberty Bike from Tririg, is based on a Cervelo S5 (previous model) and has road bike geometry. It's NOT a TT bike made into a road bike, it's exactly what others have mentioned here...an Aero road bike made into a TT bike (kind of)

Not that it matters, cause you clearly have made your mind up ignoring 3 pages of advise :shock:

/Martin

_________________
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Ohh okay! I just knew "plug" was something to put inside a hole... yikes


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PostPosted: Tue Sep 12, 2017 3:50 pm 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
Martin.dk wrote:
alcatraz wrote:
I'm just playing with the idea. I can't afford a new bike for another year at least.

It was never my intention to annoy anyone. I understand that people who do race have to abide by the rules and don't really think out of the box.

You say poorly fitting and poorly handling. The fit can be helped by choosing a suitable size (most importantly to get the stack/head tube right). If the size is big enough to bring the base bar (still streamlined) in the right height I'll be doing ok, don't you think?

The idea that I love is that a TT bike can be made fairly light and is not restricted in it's tube profiles like all the aero bikes. The place on road and aero bikes that is still quite underdeveloped is the cockpit area. My effort is to bring aero efficiency to this area without degrading the fit too much.

My current bike has a quite extreme position already. My drops are quite close to my front wheel. I've ridden thousands of km like this and start to feel very good. My issues are with being aero and braking downhill. I'd like my next bike to improve in those areas.

I'm not racing. I'm an amateur mechanic that likes to try out some ideas and I don't like being restrained to these three categories climb/aero/tt or the UCI. I'm always riding a lot of everything on my routes so even if I did have three bikes I wouldn't have the one I needed for that particular moment. (climb/flat/descent)

I'm attempting to come closer to an efficient do-it-all bike.

/a

Edit: This idea was inspired by the build done by tririg: Liberty bike.
Image
Image

Bike would look somewhat like this 2/3 of the time.
Image


That bike - the Liberty Bike from Tririg, is based on a Cervelo S5 (previous model) and has road bike geometry. It's NOT a TT bike made into a road bike, it's exactly what others have mentioned here...an Aero road bike made into a TT bike (kind of)

Not that it matters, cause you clearly have made your mind up ignoring 3 pages of advise :shock:

/Martin


There is no S5 disc brake and bars+stem are not as well integrated.

I'd love someone to suggest me a light-ish disc brake aero bike with integrated bar+stem (without drops) with nearly naca profiled tubes, that is not super uncomfortable or has shit handling.

Ok so that bike might not exist. How can I come as close as possible? I'm listening and open to suggestions.

What's with the bad temper with so many here?

/a


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PostPosted: Tue Sep 12, 2017 4:58 pm 
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Joined: Fri Apr 21, 2017 3:08 am
Posts: 52
It's not that people have a bad temper, it's that you asked for peoples thoughts, people gave them, and then you just argued with them.

Here's a quick list of aero disc bikes that I could remember off the top of my head:

Rose X-Lite CWX Disc
Scott Foil Disc
Giant Propel Disc
Canyon Aeroad Disc
Specialized Venge ViAS Disc
Cervelo S3 Disc
Merida Reacto III
Ridley Noah SL Disc Aero+
Pinarello F10 Disc

None of those have an integrated bar+stem without drops (why you want this I still don't know) but I'm sure you can figure that out on your own.

You've made up your mind about what you want. Thing is, no one provides it or anything close in a manner that will be enjoyable to ride.

But as we've all said, go spend your money on it.


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PostPosted: Wed Sep 13, 2017 12:19 am 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
I thought I was being nice explaining my preferences. Can't we have different opinions and still help eachother reach our goals? If I had your concerns I would say "You should try a TT/tri-bike before you invest in this idea because I think it could be high risk of surprise and disappointment". Instead the suggestion is ok you havent changed your mind, then I will wish you to waste money so I can gloat at your misfortune.

If you create a topic asking for 80mm deep wheels, do you want me come in and say "Oh I would never buy that because it's really stupid and handles like an absolute pig in even slight crosswinds. The best you can buy is a tricycle with 8inch wheels."? Is this help in your mind?

I respect that we have different goals and offer my concerns without being a dick. If I don't wish or can't be helpful or contribute I don't post anything.

Many posters didn't suggest any bike but just came in to post "this idea is stupid". Well if this is ok to do then this forum would be full of just nasty language for anyone that has a different goal. These posters are just kids. We have different priorities. Do I tell you your priorities are all wrong? No if you ask a question I will try to figure out how you can best avhieve that priority even though I might not agree with it.

I get it. A tt bike is built for flat terrain. It helps me save time though for long rides at the expense of a bit of comfort and a bit of safety and a bit of handling. So far no better solution following the criteria (disc/naca profiles/integrated base bar) has been suggested. I know I'm asking a lot. It's ok not to find a perfect solution but it'd be fun to try.

I have some DIY parts on my bike. I'm open to more homebrew suggestion to avhieve the goal but so far I can't think of a good compromise.

/a


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PostPosted: Wed Sep 13, 2017 1:01 am 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
If this cannondale really is 1000/400gr thereabout it really is lighter than even some aero bikes like the aeroad.

The giant propel disc looks nice.

I will check the other bikes out. Thank you MAsshole.

Pity no disc aero bikes were designed with frame integrated base bars while not weighing too much.

/a


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PostPosted: Wed Sep 13, 2017 4:33 am 
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Joined: Thu Jul 19, 2012 6:09 pm
Posts: 1109
Location: Loveland, CO
How much do you weigh?

Here's a pic of my disk brake on my tandem. 250mm floating disk. Fully mechanical so it can handle extremely high temperature.

Image


Sent from my iPhone using Tapatalk


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PostPosted: Wed Sep 13, 2017 12:54 pm 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
pdlpsher1 wrote:
How much do you weigh?

Here's a pic of my disk brake on my tandem. 250mm floating disk. Fully mechanical so it can handle extremely high temperature.

Image


Sent from my iPhone using Tapatalk


Hi!

I weigh 63kg at the moment. Wow thats a big disc. Is this a tandem bike or is the rider a heavier guy?

Have you previously had a disc brake overheat? Did it warp and lock the wheel?

Do you know if 140 can be upgraded to 160 without changing the calipers? Just need an adapter right?

I should be light enough to rim brake as much as I like right but the grades I ride are just super steep and/or very long. I'd like to try some disc brakes to see how they are. Bring me some much needed confidence descending.

I'm cureently trying out some cork pads at the moment. They are surprisingly bitey compared to the black princes which have less bite. Weird? I'm pleasantly surprised.

Haven't tried them in the deep slopes yet.

/a


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PostPosted: Wed Sep 13, 2017 4:57 pm 
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Joined: Thu Mar 12, 2015 12:44 pm
Posts: 62
Location: Stockholm, Sweden
alcatraz wrote:
I thought I was being nice explaining my preferences. Can't we have different opinions and still help eachother reach our goals?

You claim to regularly ride descents so extreme that you're not confident on a road bike with rim brakes. I can absolutely sympathize with that. What makes no sense is your proposed solution.

As you consider a basebar an acceptable substitute for a dropbar I can only assume you do not use the drops when descending. You also seem to be under the impression that dragging the brakes is better from a heat management perspective than occasional hard braking (with allowance for cooling down in-between), it is not.

Yet an un-agile, basebar only bike with narrow levers paired to mechanical calipers and tiny lightweight rotors without heatsinks is somehow supposed to make you a safer descender? Good luck braking with fatigued fingers, overheating rotors and glazing pads. Do I have a bad temper if I pretty please suggest you learn some proper descending technique first…?

I am by no means a master descender myself and have nothing against disc brakes. In fact my next road bike will almost certainly be equipped with disc brakes, though they will obviously be hydraulic. It will however definitely not be based around a TT frame half assedly converted to road fit because that just wouldn't make for a very good bike.


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PostPosted: Wed Sep 13, 2017 8:58 pm 
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Joined: Thu Jul 19, 2012 6:09 pm
Posts: 1109
Location: Loveland, CO
I'm at 62kg but on a tandem it's a complete different ball game. I'm an opponent to disks on a road bike but a disk is absolutely a necessity on a tandem. The braking forces on a tandem is tremendous. It's an order of magnitude higher than on a road bike.

Yes, I have overheated a disk brake on a tandem. It was a different 254mm disk, one without the floating feature and the aluminum fins. The disk got so hot it was discolored. At such extreme high temperature, the brake pads started to melt and the melted resin vaporized upon contact with the hot rotor, and I lost almost all braking capability due to the vapors (a thin layer of hot gas that prevented the pads from contacting the rotors). Like a puck on an air hockey table, haha.

Stainless steel is absolutely horrible at heat conduction. The 254mm disk that you see has an aluminum layer sandwiched inside stainless steel. The aluminum draws heat away from the stainless braking surface. This is Shimano's Icetech technology. My 254mm disk is made by Shimano. The difference between disks with an aluminum sandwich and one without is huge. If you are concerned about heat, don't go with Sram or Campagnolo. Here's a short video showcasing Shimano's technology and how the disk is constructed. https://www.youtube.com/watch?v=iiB_ayb-EYI

The floating feature allows the outer part of the disk to expand out from the spider, thus preventing disk warping. Hence the term 'floating'. When you see the outer part of the disk is riveted to an aluminum spider, it's called a floating disk.

Similar to my disk, the latest Dura Ace disk has the aluminum cooling fins. The cooling fins are connected to the aluminum core that is sandwiched under the stainless braking surface. Of course a disk brake is nice in the mountains. But let's not forget there's no free lunch. You do have to drag the extra weight up the hill :D

Image


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PostPosted: Wed Sep 13, 2017 9:18 pm 
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Joined: Thu Jul 19, 2012 6:09 pm
Posts: 1109
Location: Loveland, CO
Here's a very informative article on disk brakes. The poor rider crashed while riding on a disk bike. He lost all braking capability, just like what I experienced when my 254mm non-Icetech disk overheated on my tandem.

In conclusion, if you are gonna go disk, don't try to go WW. You need properly engineered frame, fork, wheels, disks, etc.

https://www.bikerumor.com/2012/02/14/road-bike-disc-brakes-are-coming-but-will-they-work/


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PostPosted: Thu Sep 14, 2017 11:09 am 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
That's a quite genius solution so sandwich aluminum between steel surfaces. It's also weight weenie, possibly inadvertedly. :lol:

What about high temperature brake pads? Is there such a thing?

I wonder if there possibly in the MTB community has been comparative tests on pads, which work best under extreme loads. Like downhill situations.

/a


Last edited by alcatraz on Thu Sep 14, 2017 12:26 pm, edited 2 times in total.

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PostPosted: Thu Sep 14, 2017 11:20 am 
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Joined: Mon Aug 29, 2016 11:19 am
Posts: 388
MayhemSWE wrote:
.


I'm going to give rim brakes another go. Currently trying some cork pads. I hear you have to replace them even more often than black princes but I don't worry about that. Never rains where I live either.

Although I havent tried them in the deep slopes they are surprisingly grippy. That I like a lot.

I use the on/off braking technique a lot too. Sometimes the off time is very short because I'm basically soiling myself. :D You know the feeling I take it....

I heard so many good things about the black princes and it never occurred to me there might be better pads out there.

I didn't mean to make anyone feel uncomfortable. Sorry if I did.

To break speed records I need something nice and aero. Still going TT along my climbing bike but I might lose the disc brakes. Still like the lightness of these cannondales though. Bottom brackets are not very good tolerance but light BB30A standard. It's if you can call it that, a TT bike good for some grades.

/a


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Posted: Thu Sep 14, 2017 11:20 am 


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PostPosted: Thu Sep 14, 2017 8:25 pm 
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Joined: Mon Jul 24, 2017 12:02 pm
Posts: 446
I tried the Shimano RT-900 rotors on my new build and the shape of the braking surfaces causes wub-wub or gobbling noises under light pressure. Now I'm using Campy H11 rotors, and the large slits in the rotors are making zipping noises. Seems like SRAM Centerline rotors are generally quietest.


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