Racing Dan

Then why are they made from carbon. Alloy in the same shape is equally aero.

Bah Humbug

What did we do before we had GCN to enlighten us?

Hermes

I will give up my lightweight wheels when you can pry them from my cold dead hands.

tyrion

Rivendell Reader.

Iride01 

Maybe I'm wrong but everyone seems to be minimizing the importance of wheel mass for when it counts the most.

Lets say two riders identical in power output weight and every thing else physiological. Bikes are identical in every way including weight, but one has lighter rims. (don't over think it guys, I know some of you are having trouble with identical bikes but ligher rims. GET OVER IT! <GRIN>

Any how, after a 180 km stage on a tour they arrive at the 200 meter mark from the finish line at the same time having exactly the same energy reserves. Who wins the sprint? The one with the lighter wheels?

Don't tell me that the little bit of difference doesn't mean any thing. A win is a win.

Now if we are strictly talking about us wannabe's then probably I can see there isn't enough there to really matter. Even so, lighter wheels are generally an easy way to lighten an existing bike.

upthywazzoo 

Is there a possibility in this universe that the sprint is longer, and the heavier wheels carry enough momentum to allow the rider to coast past the one with lighter wheels when their sprint energy is flagging?

Marylander

I don't care either way myself but was it Moser who had the wheels he used for his hour record declared illegal or maybe they set the minimum weight after his attempt (might have been some diameter issues too). I wonder if there are any online vids on it. I'll have to look. Of course, in an hour record you only want to accelerate at the beginning (maybe the end if you've got a little juice left but that would mean you left some time on the table). Do you keep some heavy aero wheels for time trialing? I've been out of the cycling world for awhile. What are triathletes using nowadays? Yes, no answers just questions.

scuzzo

well, they look cool... i guess..

woodcraft

Makes sense. That's probably why tennis pros use the lightest racquets- so they something left at the end of a five set match.

upthywazzoo 

And sound cool!

Ferrouscious 

So at what point does added weight become negative? Maybe we all need to ride disc wheels made of steel.

upthywazzoo 

I assume there's some optimum weight that pairs well with gearing, and is based on the course (terrain, direction, elevation, surface roughness) and the weight of the system: wheels, frame, rider. Imagine for a second that if having less rotating mass was king, then we'd all be riding Bromptons. A heavier, larger, stronger rider will be less affected by the resistive forces of a heavier wheel since it proportionately represents less mass compared to the whole system.

The added weight would become a negative once accelerating it hurt efficiency in a noticeable way. Biking through stop and start traffic in a 50-10 combo, for example, would be really noticeably inefficient. If the rim is heavy enough to make you feel that, but on a smaller level and hundreds or thousands of times during a ride--then it's probably too heavy.

rubiksoval

In the context of my post, I don't know if this is rhetorical or sarcastic or genuine..?

tomato coupe

Which is why pro cyclists never attack -- it's a waste of time since it doesn't actually produce any acceleration. I guess most pro cyclists just try to "out-average" the other riders.

tomato coupe

B. Sarcastic

colnago62

I agree. Know who you are and what your strengths and weaknesses are. I know guys who rarely brake on downhills. Heat build up for them is not an issue. Me, I am a chicken, also heavy. I stick with aluminum brake tracks. As you stated, carbon clinchers have been around long enough so we know they are safe. Things can happen, but we can say that about any carbon product.

upthywazzoo 

Riding to watts is definitely a thing--especially on climbs where the maybe the goal is to just survive and not lose too much time on that stage. Riders good enough to compete on a grand tour though I suspect are close enough to each other in ability that the differences in power are less important than team tactics.

asgelle

Consider the concept of quasi-steady state then see if it applies to road racing situations.

79pmooney

If we are talking mass start racing, ie pelotons, accelerations happen when corners are taken and brakes are applied, the field comes to a hill, often when crashes happen as well as any time anyone decides to apply his legs to the race, for whatever reason (unless the field just decides to let him go. Some races are just cruises to the last few miles with everyone waiting for the sprint. Others are full on madness. When I was racing the sound of crashing bikes meant "Go - for all you are worth!" because others did and if you didn't, you were left behind. Criteriums, you sprint out of every corner.

In a race where the sprinters' teams are in full control, the pace may not be that hard, But in a race where the non-sprinter feel they have a chance, they know that their job is to get away or split the field. Those races may well be slower races but can be a lot harder.

So it isn't just breaking away. But if you are trying to go with a breakaway that's leaving, getting a foot or two closer may be the difference between latching on and being reabsorbed by the field after wasting a lot is energy.

jbchybridrider 

I'm probably beating a dead horse since my earlier post here. But anyway I do have a set of sub 1000g hors category wheels, there awesome like everyone says about light wheels but I notice just as much when powers taken out of the cranks they stop dead fast.

tomato coupe

I don't see anything quasi-steady state when a pro cyclist attacks in a race. The whole point is to accelerate quickly to create a gap, so that anyone following the attack has to put in a big effort to stay with the attacker. Anything that helps the attacker accelerate more quickly (or slows the followers' accelerations) can make a difference.

asgelle

No, but if you look at the equations of motion as in Martin et al. https://www.recumbents.com/wisil/Mart...%20cycling.pdf you would see there are acceleration terms relating to wheel rotation. A simple scaling analysis would show that the magnitude of these terms, proportional to acceleration, are orders of magnitude less than the terms dependent on velocity to some power. Therefore when integrating the equations to get speed or distance travelled, ignoring these acceleration terms doesn’t affect the result in any meaningful way.

colnago62

I think that it doesn’t happen until the right selection occurs. Like on a climb after the tempo has whittled it front group down to the contenders.

tomato coupe

What difference does it make when it happens? If you attack, you want to accelerate quickly to open a gap.

tomato coupe

Both FireFox and Safari tell me that link is a "security risk" and won't open it, so I can't comment on it.