UCI expected to approve Road Disc Brakes for 2016

[g-boaf]

From memory aero is more important than weight until you start ascending at 5% or steeper. Something along those lines anyway.
Your Cervelo will be faster everywhere bar going up steep climbs.
It will be quicker and safer coming down them though I expect.

Aside from the brakes, the Canyon is nicer on descents too especially when there are wind gusts.

Is that the wheels though? From memory the Cervelo runs deeper rims.

Got so used to deep rims now I don't notice them anymore. Nothing under 50mm deep on road.

Little bit, not too deep. They are DT Swiss 1450.

Canyon is on Fulcrum Zero Competizione until the Xentis rear wheel gets a new hub.

[Duck!]

From memory aero is more important than weight until you start ascending at 5% or steeper.

The biggest effect by far on both weight and aero is the nut on top of the saddle.......

Sure. If you have the same rider in the same postion on different bikes, as you would, then aero matters more than weight for the bike. Yes not a huge difference but it is there.

Aero wheels are a good analogy. Deep carbon wheels are notably faster almost everywhere.

Put different riders on the same bike. Then the aero & weight effects become significanly relevant.

[Mr Purple]

Put different riders on the same bike. Then the aero & weight effects become significanly relevant.

This is the truth.

When people start saying things like 'aero is faster than weight' it comes down to the terrain you ride, but also more importantly how much you weigh yourself.

Some of us feel the effect of weight a lot more because we weigh 60kg odd. So a bike being a 1kg heavier for us makes a far bigger proportional difference to us than a normal sized human's bike being a 1kg heavier.

My gravel bike's 2kg heavier than my road bike and I can definitely feel it.

[warthog1]

Put different riders on the same bike. Then the aero & weight effects become significanly relevant.

This is the truth.

When people start saying things like 'aero is faster than weight' it comes down to the terrain you ride, but also more importantly how much you weigh yourself.

Some of us feel the effect of weight a lot more because we weigh 60kg odd. So a bike being a 1kg heavier for us makes a far bigger proportional difference to us than a normal sized human's bike being a 1kg heavier.

My gravel bike's 2kg heavier than my road bike and I can definitely feel it.

Fair point about the weight of the rider.
I am 76kg doesnt make a heap of difference to me unless I am riding moderate to steep climbs.
My gravel bike is about 1kg heavier I notice the drag of the gravel tyres.
Put road wheels on it and there is far less difference. I have approximated my road position on it though. After thousands of road ks it just works for me. Narrower bars and lower stem than it came with.
That is for the TCR v the Revolt. Neither have aero tubing.
Were I to still race it would be on the S5 with Zipps. That will only fit narrow tyres though and I dont race.

Weight is not as significant as most riders probably believe. Even with no aerodynamic improvement, a 1 kg difference has a relatively small impact on road speed. Conversely, if you start with a setup that has relatively high drag, a 1kg mass difference could be spent on a huge amount of aerodynamic optimisation. For the same rider and power output you could see at least 20W power savings on a flat road when comparing a classic round tube frame with low-profile wheels to a modern race bike. So perhaps a simpler question to address this phenomenon is how much should a rider care about weight or aerodynamics? While it is much easier to feel and measure the weight of a bike, for almost all riders and scenarios, aerodynamic optimisation will have a much greater impact on your on-road speed than reducing the weight of the bike.

https://bikerumor.com/aerodynamics-vs-w ... -cyclists/

[g-boaf]

Put different riders on the same bike. Then the aero & weight effects become significanly relevant.

This is the truth.

When people start saying things like 'aero is faster than weight' it comes down to the terrain you ride, but also more importantly how much you weigh yourself.

Some of us feel the effect of weight a lot more because we weigh 60kg odd. So a bike being a 1kg heavier for us makes a far bigger proportional difference to us than a normal sized human's bike being a 1kg heavier.

My gravel bike's 2kg heavier than my road bike and I can definitely feel it.

Fair point about the weight of the rider.
I am 76kg doesnt make a heap of difference to me unless I am riding moderate to steep climbs.
My gravel bike is about 1kg heavier I notice the drag of the gravel tyres.
Put road wheels on it and there is far less difference. I have approximated my road position on it though. After thousands of road ks it just works for me. Narrower bars and lower stem than it came with.
That is for the TCR v the Revolt. Neither have aero tubing.
Were I to still race it would be on the S5 with Zipps. That will only fit narrow tyres though and I dont race.

Weight is not as significant as most riders probably believe. Even with no aerodynamic improvement, a 1 kg difference has a relatively small impact on road speed. Conversely, if you start with a setup that has relatively high drag, a 1kg mass difference could be spent on a huge amount of aerodynamic optimisation. For the same rider and power output you could see at least 20W power savings on a flat road when comparing a classic round tube frame with low-profile wheels to a modern race bike. So perhaps a simpler question to address this phenomenon is how much should a rider care about weight or aerodynamics? While it is much easier to feel and measure the weight of a bike, for almost all riders and scenarios, aerodynamic optimisation will have a much greater impact on your on-road speed than reducing the weight of the bike.

https://bikerumor.com/aerodynamics-vs-w ... -cyclists/

Mr P and I are both a lot lighter than you - I've got 17kg less than you. So when I'm going uphill on a 6kg bike it feels like the thing has a motor attached to it, the difference is quite crazy in comparison with a 7.84kg bike (the S5) - the 6kg Canyon is just much faster up any hill, even small gradients of 4-5%.

I've ridden both the Canyon and the Cervelo S5 up Col du Glandon and with the Canyon (on alloy wheels actually) it felt fairly easy.

https://www.cyclingcols.com/col/Glandon

On the day with the Canyon I had Rick Delaney with me. Interesting person.

That's the thing about the S5, it's just so heavy. That's the penalty of it being aero.

[warthog1]

Mr P and I are both a lot lighter than you - I've got 17kg less than you. So when I'm going uphill on a 6kg bike it feels like the thing has a motor attached to it, the difference is quite crazy in comparison with a 7.84kg bike (the S5) - the 6kg Canyon is just much faster up any hill, even small gradients of 4-5%.

I've ridden both the Canyon and the Cervelo S5 up Col du Glandon and with the Canyon (on alloy wheels actually) it felt fairly easy.

That's the thing about the S5, it's just so heavy. That's the penalty of it being aero.

Fair enough and you are both good climbers. I am not. Yes up steeper hills and with that bike weight being a higher overall percentage of total weight it would make more difference.
Still the weight penalty for aero is steadily reducing so you can get closer to the best of both worlds than you could previously.

[warthog1]

With respect to disc brakes, weight and hill climbing, some of the reaction to this was amusing
https://cyclingmagazine.ca/sections/new ... isc-brakes

[AndrewCowley]

So when I'm going uphill on a 6kg bike it feels like the thing has a motor attached to it, the difference is quite crazy in comparison with a 7.84kg bike (the S5) - the 6kg Canyon is just much faster up any hill, even small gradients of 4-5%.

This is also my experience of light bikes and going uphill. Why then do people say weight does not matter? It matters a lot when going uphill. Why does that not matter?

[g-boaf]

With respect to disc brakes, weight and hill climbing, some of the reaction to this was amusing
https://cyclingmagazine.ca/sections/new ... isc-brakes

You can make them light and there are some light disc brake bikes out there. Some of the extreme light rim brake bikes out there (sub 5 kilograms) I would not like to ride on descents. You hear stories of brakes that are only just barely adequate.

My lightest bike might not be quite as good as a disc brake bike for braking power but compared to some of those weight-weenie builds, it can still stop (on alloy wheels at least).

[warthog1]

With respect to disc brakes, weight and hill climbing, some of the reaction to this was amusing
https://cyclingmagazine.ca/sections/new ... isc-brakes

You can make them light and there are some light disc brake bikes out there. Some of the extreme light rim brake bikes out there (sub 5 kilograms) I would not like to ride on descents. You hear stories of brakes that are only just barely adequate.

My lightest bike might not be quite as good as a disc brake bike for braking power but compared to some of those weight-weenie builds, it can still stop (on alloy wheels at least).

Here you go GB. Aero, disc and light.



Not too sure about Ti rotors though.

[g-boaf]

Oh that thing: https://ciclimattio.com/en/p/cannondale ... rrency=AUD

Not bad value given my uber-light Canyon was $18,599 fully built up in 2018. Unfortunately the Lab71 has Shimano Dura Ace. Won't touch anything Shimano going forward.

Someone did a medium build with 7kg:
https://weightweenies.starbike.com/foru ... p?t=174407

This one was a bit special as well:

https://www.youtube.com/watch?v=Y9t-0nc6JdU

my old CF Evo had a frame weight of 685g, crazy light.

And this is the disc brake Evo up Alpe D'Huez:



That bike he has there is 5.86kg.

Those handlebars on that thing, don't even think about trying to acquire them - they are very, very hard to find. When it came out I tried to obtain them for my older CF Evo as a weight saving measure. Not available except as warranty replacement on a CF Evo Disc.

[warthog1]

Oh that thing: https://ciclimattio.com/en/p/cannondale ... rrency=AUD

Not bad value given my uber-light Canyon was $18,599 fully built up in 2018. Unfortunately the Lab71 has Shimano Dura Ace. Won't touch anything Shimano going forward.

Someone did a medium build with 7kg:
https://weightweenies.starbike.com/foru ... p?t=174407

This one was a bit special as well:

https://www.youtube.com/watch?v=Y9t-0nc6JdU

my old CF Evo had a frame weight of 685g, crazy light.

And this is the disc brake Evo up Alpe D'Huez:



That bike he has there is 5.86kg.

Those handlebars on that thing, don't even think about trying to acquire them - they are very, very hard to find. When it came out I tried to obtain them for my older CF Evo as a weight saving measure. Not available except as warranty replacement on a CF Evo Disc.

It doesn't have a Shimano chainset which has caused grief.
It has Shimano brakes however. Definitely a positive over Sram by all accounts and oil instead of brake fluid is a bonus.

All too expensive for me. I take what I can afford. It therefore aint going to be particularly light.

[CmdrBiggles]

Ah, well—... I would be careful holding anything against SRAM (founded in early "twistie" road shifters, then in MTB circles something like 37 ago) — brakes or drivetrain, particularly but not limited to the sharp, smart FORCE group. I have never used brakes (or anything SRAM!) so damned good (do these brakes know about my habits!? ), with the FORMULA X Italian job on my GT Zaskar until now being the benchmark for sharp braking.

[warthog1]

They have all had their problems. There were a number of failed Sram rear derailleurs here a few years back but sorted now.
Shimano's ultegra and dura ace crankset failure has been poorly handled it appears.

I have always run Shimano and it has been super reliable for me but if I found a Sram equipped bargain like you did, I'd have grabbed it also.

[CmdrBiggles]

They have all had their problems. There were a number of failed Sram rear derailleurs here a few years back but sorted now.
Shimano's ultegra and dura ace crankset failure has been poorly handled it appears.

I have always run Shimano and it has been super reliable for me but if I found a Sram equipped bargain like you did, I'd have grabbed it also.

Fair enough. Personal experiences have weight. And the TCR DISC 0 is not a bargain by my financial yardstick!
I was left a bit cold with the ULTEGRA groupset on a lower-spec GIANT TCR test-ridden for fit-position purposes. There were no SRAM Rival or Force-equipped XS bikes at the dealer at the time; had to look elsewhere at TREK (several bikes, Rival and Force, like the Emonda, which I initiallyl had lusty eyes for!) and the recommendation to me was to "go SRAM". Now I am using SRAM Force the difference in speed and precision is very stark from the earlier experience with ULTEGRA. Maybe something wasn't up to adjustment, or a disconnect in the signal(s)?

I am in absolutely In awe of how technology has done away cables — something that could never have been dreamed of (even with gin and lamingtons over a way-too-lively campfire) waaaay back in out bicycle touring then road riding days — downtube shifters all the way! What might be next? Bikes that ride themselves (e.g. no rider — the ultimate in aerodynamics!)

[g-boaf]

Shimano's ultegra and dura ace crankset failure has been poorly handled it appears.

It was a trainwreck - if they had been on the front foot it could have been a lot better and their reputation would have been better off. Amazingly there are still folk out there who don't know about it, I mentioned it to one rider who had no idea.

The only thing I don't like so much on disc brakes is bleeding them. I've only ever done it once with hydraulic Magura RT8 TT rim brakes, never the SRAM disc brakes even though I have the kit to do it. That's one of those things I could probably learn but just leave it to the bike shop.

[Andy01]

As a non-roadie riding a bike for exercise where (within reason) bike weight doesn't matter, I find this thread and the recent turn it has taken into weight quite intriguing.

It seems that saving even minute amounts of weight (like 100g) is very important to some riders (as per similar discussions in a recent titanium bolt thread), and comments that weight does matter (when talking probably a difference of 500g or less).

When the combined weight of the rider + bike is probably approaching 90kg (or more in some instances) how can a mere 100g or even 500g be THAT important ? As a percentage of total weight 100g is around 0.1% which is surely completely insignificant or immeasurable unless competing at a VERY high level. Even 1kg is marginally over 1% which would be within measurable limits. I find that my "performance" varies on a daily basis and seems to have more to do with how I am feeling, how I slept, and temperature or wind conditions on the day - these influences would have a far larger effect (for me) than shedding a few hundred grams of bike weight. Under track conditions and strict training diets / regimes it is possibly a different story, but most of us mere mortals don't live or ride like that.

Surely most people's body weight varies by significantly more than 100g (or even 500g) over the course of 24 hours (never mind a week) depending on what they have eaten or drunk and various bodily functions (including simple sweating). For me, on the most days that I ride, between 7am and 10am I typically consume at least 1000g of water (much of this on my daily ride), another 250g of coffee, and probably another 200g of cereal & milk - total 1450g consumed. How does a few hundred grams of bike weight matter ? I typically weigh myself every morning at the same time (just after getting up) and my weight will vary between 64kg and 66.5kg over the course of a week sometimes - depending on what I have been doing & eating/drinking - massively more than any of the differences being mentioned here.

I just cannot get my head around what the fuss is, especially for non-elite competitive riders.

Perhaps someone can educate me

And for the record I also struggle to get my head around why 8 years after this thread was started (and presumably it is also distant history by now) the debate of discs vs rims is still a thing. Reading the comments here (and personal experience) it is a complete no-brainer in favour of discs. People who favour rims seem to be very resistant to change

[g-boaf]

I just cannot get my head around what the fuss is, especially for non-elite competitive riders.

Your right, I'm not elite, one leg is very dodgy, I have a relatively crappy 265w FTP (4.49w/kg) so I might as well just give up, get unfit and start advocating against those red-light running cyclists.

Given I went from over 5w/kg, down to 2.1w/kg and now up to almost 4.5w/kg and back to riding up and down mountains, if I want to ride a 6kg bike then so be it. When I do ride up hills I go find the biggest ones so a lighter bike is useful.

Perhaps someone can educate me

Well it's probably pretty pointless trying given your post, but if you ride enough then your weight stays pretty constant. It's not tricky or complicated - depending on how much riding you do, that offsets what you eat (unless you are eating all the wrong things). So how much are you riding?

[warthog1]

I didn't read it that way GB.
Disc brakes work better.
Aero is more important than weight.
Agreed.
Yes as you get lighter the percentage of weight difference 1kg represents does become larger.
It still only really matters on steep climbs though.

I posted a link further up the had plenty of info confirming aero v weight and the relative importance.

Choose both is possible these days.

[warthog1]

I can't edit my post on the phone anymore. Just wanted to add that yes you do alot of clinbing so weight we ould be more important to you than most.

With respect to body weight I regularly come home a kilo or two lighter than I went out. Often do 100k rides.
I should drink more.
Hope I aint damaging my kidneys.

[am50em]

As a fitness rider and weighing 92 kg, bike weight is not a high priority. But I have gone from steel to aluminium to carbon frame so bike has been getting lighter. I have cracked the Al and carbon frames (and got replacements). I wish they would make the frames heavier for strength and longevity. I am saving up for Ti frame bike and hoping it will last a lifetime.

[Andy01]

I just cannot get my head around what the fuss is, especially for non-elite competitive riders.

Your right, I'm not elite, one leg is very dodgy, I have a relatively crappy 265w FTP (4.49w/kg) so I might as well just give up, get unfit and start advocating against those red-light running cyclists.

Given I went from over 5w/kg, down to 2.1w/kg and now up to almost 4.5w/kg and back to riding up and down mountains, if I want to ride a 6kg bike then so be it. When I do ride up hills I go find the biggest ones so a lighter bike is useful.

Perhaps someone can educate me

Well it's probably pretty pointless trying given your post, but if you ride enough then your weight stays pretty constant. It's not tricky or complicated - depending on how much riding you do, that offsets what you eat (unless you are eating all the wrong things). So how much are you riding?

I normally ride 6 days a week - relatively short ride of around 13km/day, mix of paths, roads, and a bit of gravel with some hills. My weight has been relatively constant between 63.5kg and 66.5kg for almost 4 years now - most of that fluctuation depends on what I have been doing or eating etc at the time of weighing (ie. natural fluctuation rather than weight gain or loss - like gaining a bit over the festive season for example). I am 60 and my current weight is only 2kg above my weight at uni in 1986, so I am pretty happy with it.

You may have missed my point. I was querying how a mere 100-500g can make such a difference (even up hills) - worth spending hundreds or thousands of dollars to achieve, especially since it is such a minute amount compared with most rider's body weight, and especially since a rider's weight can (and does) fluctuate by hundred's (or more) grams over the course of a day. As above I am referring to "normal" riders, not people in a competitive situation.

Drink a bidon of water = 600-1000g, eat a snack = 100-200g, have a meal = 300-500g (more for a main meal with a couple of beers etc), a full bladder = 400-600g, a full bowel = who knows, probably at least as much, sweat is at least 1000g/day for non-exercising people and up to 10,000g/day for heavy exercising people. All of these things are done daily, so of course a rider's (person's) weight fluctuates quite significantly.

All of these things have (significantly) more impact than a couple of hundred grams of bike weight - especially when a couple of them are combined. To me it seems a bit like having a policy of never filling the (ICE) car's tank above 1/4 full (to save a few kgs) so the engine is doing less work to drag fuel around - in reality the difference is almost imperceptible.

Based on your number above of 4.5W/kg, that extra 100g requires an extra 0.45W to push around - is that even measurable with any accuracy (maybe 0.05% of the measurable range of most power meters - I would be surprised if any were that accurate, or even close to - an accuracy of ±2% would seem optimistic) ?

I am not suggesting that a lighter bike is a bad thing (at all) - except for the likely reduction in durability that may accompany the weight reduction, and the fact that a heavier bike may make the rider work harder producing better fitness results (assuming they are not racing). And if a rider has the desire and cash to chase weight, that is obviously their choice. I am trying to understand why there seems to a fixation with many roadies about saving every last gram on the bike when the rider is usually a massively greater influence ?

[AndrewCowley]

It's simple ... A light bike is more responsive, more fun to ride, quicker to accelerate and goes up hills faster.

[g-boaf]

I was querying how a mere 100-500g can make such a difference

Try riding a 7.8kg bike up a couple of hills with 1000m+ elevation gain for each hill and then ride a 6kg bike on the same ones. You feel the difference pretty fast. When you've done that, come back and tell us "no, I couldn't feel any difference at all".

the fact that a heavier bike may make the rider work harder producing better fitness results

What makes you get better is the correct training methods. Jumping on a 16kg bike won't achieve much on its own.

I am not suggesting that a lighter bike is a bad thing (at all) - except for the likely reduction in durability that may accompany the weight reduction,

I have a 6kg bike with over 30,000km on it. it does commutes, riding up and down mountains, overseas travel. Still runs and looks like new. The only major drama was a Dura Ace 9100 recall and a rear wheel hub eventually gave up for the first time since 2017. A few chains replaced, a bottom bracket replaced and that's it. Pretty durable by my expectations. It's very reliable.

[am50em]

But the bike weight is only a small part (~10%) of the total weight. If you are at your lightest weight you can be, then reducing bike weight is the only way. Otherwise reducing rider weight would be more advantageous.