105 vs ultegra vs dura-ace



ScienceIsCool said:
Who said heavier is faster? Lighter is faster. Everyone agrees. Just that it is only faster by an exceedingly small amount when we talk about total system weight. That makes small weight changes irrelevant to quite a few of us.

John Swanson
www.bikephysics.com

Dang, John Yer usin' that logic thing again, ain't ya?
 
ScienceIsCool said:
Okay. I'll use your example. If you assume that over that 100 hilly miles (160 km) you spend half your time climbing and accelerating.... and you're putting out an average of 400 Watts... at an average of 40 km/hr...

That's 4 hours of riding = 1,440,000 Joules expended in total. The extra 0.25% cost you...

A grand total of 1800 Joules. Not. A. Hell. Of. A. Lot. That's 4.5 seconds over a 4 hour ride at a greatly exaggerated pace, power output and assumption about climbing/accelerating.

Real world? I'd say that other factors would swamp the data and make the difference unmeasureable.

John Swanson
www.bikephysics.com

Would you PLEASE stop making sense?!
:D
 
Camillo said:
I can't imagine that you'd be able to measure any difference that would be of a magnitude great enough to be anywhere near as important as tires and tire pressure, body positon on the bike or even the choice of jersey and helmet.
ScienceIsCool said:
For 200 grams difference, you would be better off worrying about the shape of your sunglasses or whether you've shaved or not.
Ok, you guys have convinced me not to stress out about small 200 gram weight savings too much (although my bike is a lot more than just 200 grams too heavy---more like a full kilo heavier than many guys in my last race), but several of you have mentioned that one might be better off worrying about aerodynamics. How important to performance is an aero frame, aero wheels and even an aero helmet? I am pretty sure that my setup doesn't score very well in those categories either.
 
I really take my hat off to those of you who can calculate these sort of things.

If 200 grms less saves about 4.5 secs over 4 hours on a hilly ride, then I guess there will be people (likely racers) who will be able to justify the spend.


Now, what we're not measuring here are the perceived or psychological advantages of knowing that your gear is lighter than someone else’s.


Mind you, it also works in the opposite direction.... if someone else is on DA and you're on 105 these perceptions can kill you (like the friend of our esteemed steleem, whose average speed was reduced by 3 mph when he changed from Chrous to 105)


I guess we jumped the discussion type from informal to academic to full blown scientific to psychological. My conclusions are:


- Is there a real performance advantage from using lightweight gear?
.. Quite possibly yes

- Is it significant?
.. How long is a piece of string?. The question should be "is it significant for you?" and how much are you willing to spend on it

I know that I wont pay 2K for the new SRAM Red or slightly less for Record Ultra Torque, because in my shape and form and type of riding I do, it makes ZIP ZERO NADA ZILCH difference to me.

But...to each its own.
 
CAMPYBOB said:
So it would take an extra 0.25% energy/power no matter how many times a rider had to accelerate the system.

Which is how much over a hilly 100 miles?
An extra 0.25%.

e x 100.25% is still e x 100% + e x 0.25%. So it is an extra 0.25%.

(where e is energy output)

so for every 1000 calories expended, you will use an extra 2.5 calories. Whoa. Massive. That could be the extra few drops of coke in the bottom of the can when you throw it out.

You are still arguing in your own little world. You keep talking absolute **** about adding weight to bikes. That is a stupid, stupid thought, reserved for your own little argument.

Lighter is faster, but a small amount of weight is going to make next to no difference. Certainly no difference identifiable outside the normal variable range.

No matter how many accelerations you make, no matter how many hills you climb, 200g is still 200g. It doesn't magically gain weight over a greater distance. Try it next time you ride. Weigh your mp3 player. It will still weigh the same at the end of the ride.
 
If 200 grams (roughly 1/2 pound) costs 4.5 seconds over a hilly 100 mile course, then 10 pounds costs about 90 seconds.

Right?

Anyone want to throw a leg over that old Schwinn Continental and try to stay within a whopping 5 minutes of me on that course? Five whole minutes buys over 50 pounds! It should be easy, right?

Do you think you could hold your two test times within 10 minutes of each other? I don't.

One of these weighs 4.8 pounds:
DSCN4476.jpg


Let's stick two paving bricks in your jersey...ok, let's duck tape them to your BMC...and see you stay within 90 seconds of your best 100 hilly mile circuit time.

You play the role of the believing scientist with a burning desire to prove your calculations correct. I'll be the guy sitting at the top of the last hill running the stopwatch. Laughing.

The numbers say one thing. Life says another. I ride a bicycle in the real world. Not on a chalkboard.

Every acceleration of that extra 1/2 pound costs more energy trying to stay with that imaginary duplicate of you on a lighter bike. Every climb dragging that 1/2 pound up a long steep grind burns another match keeping up with yourself. Every punch over the top to close that little gap opened up by the lighter bike burns more calories.

Every additional effort compounds itself. A little weight...a lot of weight. No matter the mass, in real life there's a real penalty to pay for it.
 
All cobblers.

When I do cyclo-cross I use an old, 1970s steel bike with steel wheels, and it is a joy on rough surfaces. I say because the rims are so heavy they like to keep spinning.

When I do MTB I run a rear tire as wide as will fit in the frame and so flat I'm right on the edge of getting snake bites, yet get lots of traction.

When I did the PBP this year I used Dutch Perfect tires as I knew that'd save me time in having to stop and fix punctures.

When I commute to work I use a super-market nasty, as I know one day it will be stolen, and I'll be well annoyed if I've shelled out more than absolutely necessary. And oh boy, when I fly by those on their super aero, super expensive, carbon jobbies that have to slow down for the smallest hole in the tarmac, and drive twice as far as they weave to-and-fro 'cause they can't hold a straight line 'cause their elbows are on the stem, are they well upset or what.

It's all horses for courses.

On a really smooth indoor track, or to a top flight pro who can't train any higher, absolute lightest weight might mean something, but for others it's mostly in the mind, put there by marketing people.

For us lesser mortals, a little extra training, a little more sensible diet, is by far the cheaper and more reliable method of improving your times on any bike.
 
you are desperately trying to not get the point. there is complete consensus amongst every single poster that increasing weight will have an effect. in the realms of a reasonable scenario the difference that a small amount of weight makes is very small. sure increase the weight by 10, 50 or 100 pounds and the difference becomes greater. in fact again that has been agreed.

if you increase weight by something that is likely to be seen in a real-world situation, say 1-2 kg then ultimately the difference in performance is so small that i'd think any experiement involving real humans would give non-reproducable results. especially outside of the parameters of time-trialling where bunch dynamics will play the largest role.

i have a race bike that weighs in at 7.5kg. i have a training bike that weighs in at just under 8.5kg. i regularly race my 'training' bike for a variety of reasons. the road course that is my clubs home circuit is hilly and the average race is 70km. the difference in my performance on either bike is zero. zip. zilch. nothing. in fact i've actually had a couple of better results on the training bike with long escapes.

as others have pointed out there are plenty of pros riding bikes well above the UCI limit. they do it for a variety of reasons, better aerodynamics in the wheels for example. in fact my racing experience is that it's only a very small minority of (professional) riders who are particularly anal about the weight of their rigs. most are simply given a bike, they tweak items for comfort like the saddle etc, then they ride them. i regularly race with full and part time professionals and most couldn't even tell you the gross weight of their bikes if asked.

http://www.cyclingnews.com/tech/2007/probikes/

In fact for every bike shown there under 7kg you'll find one heavier than 7kg.

--brett
 
I'm slightly over the UCI limit, myself. That doesn't change the fact that if i drop another 200/300 grams that I will not be able to detect that weight decrease or ride faster using less energy because of it. Noticeable to me.

Some say it's insignificant. I say it is not.

We've all raced backup bikes or training wheels of necessity and/or choice.

I've done well on a backup iron and I've done poorly on it. More often than not, I did not race as well on heavier equipment. Particularly in crits or hilly races. I'll be the first to admit there's a ton of variables to consider, but feeling that mass coming out of corners was NOT psychological.

And about that aerogear...the manufacturers are doing their damndest to make it lighter every year. Not at the behest of sales & marketing, but due to demands from riders that want to win.

Think you could tell the difference between only 90 grams on a rear wheel? I can feel it by changing from training tires to racing tires. No slide rule required or pocket protector required. Just a few jumps in the parking lot.
 
This thread is amazing, it has kept me amused for days now. I think everyone has missed the most important weight burden. Yes, that rushed **** when you've left nearly 250 grams up the tube. Before I do any ride I make sure as much as possible that I've completely emptied the sewage tank. Besides carrying less weight, I psychologically feel better (emptier). Have you ever climbed a long hill when you're bursting for a **** and all you can really think about is getting home before you explode.

Apologies for reducing this thread to its lowest level, but just my 2 yens worth.:D Tyson
 
Sillyoldtwit said:
This thread is amazing, it has kept me amused for days now. I think everyone has missed the most important weight burden. Yes, that rushed **** when you've left nearly 250 grams up the tube. Before I do any ride I make sure as much as possible that I've completely emptied the sewage tank. Besides carrying less weight, I psychologically feel better (emptier). Have you ever climbed a long hill when you're bursting for a **** and all you can really think about is getting home before you explode.

Apologies for reducing this thread to its lowest level, but just my 2 yens worth.:D Tyson
I think your suggestion is the most immediate weight saving many of the posters here could manage, and quite possibly substantially more than 250g. ;)
 
threaded said:
I think your suggestion is the most immediate weight saving many of the posters here could manage, and quite possibly substantially more than 250g. ;)
That's gonna leave a mark!

Skid mark!:D
 
CAMPYBOB said:
I'm slightly over the UCI limit, myself. That doesn't change the fact that if i drop another 200/300 grams that I will not be able to detect that weight decrease or ride faster using less energy because of it. Noticeable to me.

Some say it's insignificant. I say it is not.

We've all raced backup bikes or training wheels of necessity and/or choice.

I've done well on a backup iron and I've done poorly on it. More often than not, I did not race as well on heavier equipment. Particularly in crits or hilly races. I'll be the first to admit there's a ton of variables to consider, but feeling that mass coming out of corners was NOT psychological.

And about that aerogear...the manufacturers are doing their damndest to make it lighter every year. Not at the behest of sales & marketing, but due to demands from riders that want to win.

Think you could tell the difference between only 90 grams on a rear wheel? I can feel it by changing from training tires to racing tires. No slide rule required or pocket protector required. Just a few jumps in the parking lot.
CB, agree that crit racing adds another dimension that the simplified hill-climb calculation ignore. Of course mass is important accelerating out of corners, not just for hill climbing. A 1% reduction in overall mass (bike+rider) will allow you to accelerate 1% faster with the same force (torque) applied to the rear wheel, or even better, to stay near the front using 1% less wattage during the acceleration. If you're in a crit where you're making hard accels hundreds of times, that 1% power savings could make a critical difference on the bell lap. With reduction in wheel mass, the effect on acceleration is about 2x since you have to spin up the rotating mass as well as move it down the road.

Won't argue with you either about your ability to feel the lighter equipment. A lighter wheel/bike just feels more responsive. When I used to do club training crits, I remember the difference taking off the seat pack and water bottle made. Maybe some of it was psychological, but that's important too.

In summer here, I normally ride with two full bottles, close to 1500 grams, which is more than the weight of the frame for many of us. Next time I do some hill climbs in the neighborhood, I'll try leaving them at home and see how much faster it feels....maybe I'll even break my PR up the home hill :)
 
Okay. Now I know CampyBob is just kidding around. An extra 90 grams on the outside of a wheel increases your inertia (treat it like you would mass) by 0.15%. It would be the equivalent of adding ~120 grams to your frame. And you can feel that. Thanks, CambyBob. You had me there for a while. Heh. Things have gotten really silly, so I think I'm done with this thread.

John Swanson
www.bikephysics.com
 
SIC, you CAN'T feel the difference in spin-up going from a training sew-up to a racing one makes???

Seriously.
 
dhk2 said:
Of course mass is important accelerating out of corners, not just for hill climbing. A 1% reduction in overall mass (bike+rider) will allow you to accelerate 1% faster with the same force (torque) applied to the rear wheel, or even better, to stay near the front using 1% less wattage during the acceleration. If you're in a crit where you're making hard accels hundreds of times, that 1% power savings could make a critical difference on the bell lap. With reduction in wheel mass, the effect on acceleration is about 2x since you have to spin up the rotating mass as well as move it down the road.
Regardging that reduction in overall mass that you refer to, (bike + rider), assuming that one's power output stays constant and that we are not talking reduction in rotational weight that you already referred to, is there any advantage to taking 1 kg weight off the bike versus taking 1 kg off the body?
 
CAMPYBOB said:
SIC, you CAN'T feel the difference in spin-up going from a training sew-up to a racing one makes???

Seriously.
Difference is there, but tiny. It takes bugger all effort to spin a road wheel, from the heaviest to the lightest. Hang your bike in a stand, and give it a try. Spin your wheels. Seeing as your legs should be monumentally stronger than your arms, it should become clear how little effort it takes to actually spin up a wheel.

Now, 4.8lb isn't a small amount of weight for me. For a rider of 200lb, it is still a fair increase, 2.4%. For me, it is an increase of 3.3%. Add two of those and that's 6.6% (body weight only). Total system weight it's a 5.9% increase. That is a ridiculous idea, once again.

Now, When I commute, I do it with an extra 20lb strapped to my bike. Yeah, it takes more to accelerate, that is logical, but once you are moving, it stays moving. But 20lb is much more than 1lb.

Changing the system weight by 1% would require a weight drop of 760g for me. That is massive if you only have a few parts that you want to change. Now, ignoring the massive number of variables kicking around the real world, if that did lead to an extra 1% acceleration increase putting out the same power (wind resistance says it won't. Wind resistance doesn't increase linearly) and lets just say we are going from the line, so from 0 to, say, 40km/h. A 1% increase takes me to a whopping 40.4km/h. I think my opponents may just be able to hang in my draft at that whopping speed. Accelerating out of a corner from 30 to 40 will only bring a 0.1km/h boost, seeing as the 30km/h is irrevlevant, and it is only a 10km/h acceleration.

0.1 km/h is much less than the difference between a good and bad day, or sprint tactics. That is a 1% drop. Now consider a 200g drop. That is a bit more than a quarter of that. IOW, bugger all.

Bringing in your real world argument, the increase in acceleration shuold be less than that because you are assumedly in the wind if you aren't trying to stick second wheel. As everyone knows, drag increases by the square of velocity. Double the speed, you get twice as much drag. Also, to double the speed, it takes eight times as much power (cube of the velocity) so as you go faster, it takes much more power, so you better be putting out more power, otherwise that 1% gain will start to diminish. Also, assuming you are in a crit, if you are accelerating like this, your opponents are probably on your wheel, taking advantage of your draft, not using as much power or energy.

Now, as to the hilly century, if you are operating under a threshold power range for all powers, there is no reason why you would feel much different carrying an extra 200g, except fitness. I have actually logged faster times up a local climb (3km, averages somewhere around 8.4%. First half averages 12%, hitting 15) using my heavier training gear during a long ride (110km, long for me) than light gear.

as i said, 200g remains 200g.
 
Amazingly, I've followed this thread whole way too:)

I can understand the pros going all weight weenie because they don't pay for the stuff - If I was given DA I'd be happy to ride it. Any perceived benefit is probably more psychological than physical but if they 'feel' better they may well perform better.

I didn't do physics at school and don't pretend to know anything about it, but as far as uphill acceleration is concerned, wouldn't there be some sort of inertia/gravity benefit for a heavier bike going downhill which would counterbalance the extra effort uphill? Just asking - not trying to diss anyone here.

I ride 105 - never ridden anything else. In Aus 105 is $929, Ultegra $1099 and DA $2069. If I were in the market to replace it I might splash $170 extra for Ultegra but I certainly wouldn't pay more than double for DA. I could buy the wife and both kids a bike each for the difference - or maybe put it towards a tri bike for me:)

//k
 
chainstay said:
Regardging that reduction in overall mass that you refer to, (bike + rider), assuming that one's power output stays constant and that we are not talking reduction in rotational weight that you already referred to, is there any advantage to taking 1 kg weight off the bike versus taking 1 kg off the body?
Performance result should be the same. A lighter bike may feel more responsive and quicker under you, but that doesn't translate to seconds saved.

Speaking of weight loss, during the summer I normally carry two 24 oz bottles: that's 1400 grams, or somewhat more than my frame weighs. It's cooler now, so on our short ride tomorrow will cut back to one bottle. Maybe saving 700 grams will be just enough to put me out front on our speed limit sign sprint....
 
Can't you read? Weight makes no difference. Certainly not a mass as insignificant as a single kilogram!

So have that second or third crueller AND take along the 42-piece tool set. And the cell phone. And the I-Pod! And don't forget the beer!

A mere kilogram?! My good man, that only amounts to 45 seconds of time lost after a freakin' hard 100 miles of hilly riding! Not enough for the 'average' cyclist to concern themselves with! Why, you could toss a rock that far! Just go out and buy an Electra Townie and fuggeddabbouddit! Hell, no one here can even remember why they ever bought a bike from a catagory called "lightweight racing bikes" anyway!

Meh! We have guys insisting 200 grams has no effect on my long, hard ride...calculator-totin' scientists that can't feel the difference a good tire makes over a Taiwanese training clunker...bottom of the barrel groups finishing hard, hilly rides only 4.5 seconds down on the thoroughbred components after 100 miles...antique Schwinn's deemed perfect for a 6-corner crit dogfight...Lance not knowing which end of the seat points forward...steel wheels freight-training 'cross bikes uphill with flywheel effect...oy!

It's no damn wonder the Varsity Back From The Dead thread is running 2,300+ pages!