531Aussie

*Mountain climbing excluded, of course.

A special thread for all the weight weenies out there

A fast bike on flat roads is about rigidity and aerodynamics, not weight.

All the "bollockle" talk about rotational weight, and accelerating a certain mass from x speed to y speed requires 'this' much energy, etc, etc...blah, blah.....check out the heavy weights of some the track bikes at the recent World Championships. And being track bikes, they obviously don't have cassettes, brakes, etc.

Plenty of people on this forum wouldn't go near a road bike unless it was under 17.5lbs (8kg)! Theo Bos got his 17.5lb 'clyde' up to 44.3mph without a tailwind!

Damian Zielinski's Isaac.............16.3 lbs
Clara Sanchez' Look...................17 lb
Roberto Chiappa's Pinarello.......17.3 lb
Maximilian Levy's FES.................17.4 lb
Theo Bos' Koga/BT.....................17.5 lb
Dutch team pursuit Koga/BT.......17.8 lb
Stefan Nimke's FES.....................17.9 lb
Tuen Mulder's Koga/BT...............18.5 lb
Dutch team pursuit Koga/BT.......19.2 lb
Dutch team pursuit Koga/BT.......19.4 lb
Dutch team pursuit Koga/BT.......20.7 lb

https://www.cyclingnews.com/track/200...k_worlds_bikes[/QUOTE]

Accelerating a mass from 0kmh to 60kmh+ is more important in track events than anywhere else, but some of these bikes are close to, and over, 18lbs!!! And if anyone says that the big guys need big bikes, the pursuit guys aren't big, and look at the weight of the Dutch-owned BTs

the beef

I need more threads like this. My '05 steel Bianchi weighs around 24 pounds and I constantly think I should've gone with a lighter Alu frame or something..

53-11_alltheway

Haha. I keep telling noobs the same thing. LOL@ rotational inertia is the most important aspect of wheel acceleration.

mrkott3r

wtf is "rotational inertia" I did senior physics (last year) and came 3rd, but Ive never heard the term.

krazyderek

Maybe just slow adoptor's? I'd imagine they'd want stiffness over weightsavings anyday. They also don't do 10 minutes of climbing on a track. And in track wouldn't a heavier bike help carry more momentum around a turn, aswell as pick up speed faster when attacking from the top of the track?

Gyrostapo

He means rotational weight: more weight at the wheel rim, ergo, slower wheel acceleration.
It takes a bit more energy to get heavier wheels going, but they hold their speed better than light wheels. Thus, rotational weight has minimal effect on overall bike performance, unless you're in a riding situation that requires repeated braking. In that case, you repeatedly waste the energy you put into accelerating the wheels.
In climbing, heavy wheels don't slow you down anymore than extra weight would elsewhere on the bike (or on your body).

TheDTrain

I thought we already established this fact from hip's knave threads.

merlinextraligh

The heavier weights you give are for pursuit bikes (presumably with disc wheels) Only have to be accelerated once on a smooth surface. Obviously aerodynamics are going to be more important than weight on a pursuit bike. It would be interesting to contrast the weight of the the srpinters bikes with the pursuit bikes.
Also, this really is an apples to oranges comparison. Track racing at least sprinting is about big guys producing incredible power. Marty Nothstein had to lose at least 40 pounds when he went from track sprinting to doing criterium races. I bet you Marty's crit bike weighs somewhere close to the UCI limit.

badhat

i've never been on a track, but i've climbed plenty of 10K foot multi hour climbs, and both simple math and my experience suggest that in that context weight matters a bit. which is the only context (outside of vanity) i've ever heard it seriously suggested that weight matters much anyway.

badhat

i mean this forum isnt track cycling, its road biking, isnt it?

Tom Stormcrowe

That which is in motion tends to remain in Motion, that which is at rest tends to remain at rest apploes here. I suspect it may be a term unique to cycling, but the physics do apply. AKA Flywheel principle when applied to a rotating disc.

By the way, I tried a LW Giant today and the difference was incredible! I took off like I would to sprint my steelframed bike andf the Giant literally felt like I had a JATO rocket attached! Not kidding!

Dick Rhee

I don't think that that weight matters as much as some people think (ie: the endless pursuit of that 15 kg lighter stem) but there is a significant difference between climbing on my old 28 pound touring bike and my 17.5 pound road bike. On flat roads they would cuise at about the same speed, although acceleration and climbing on the old bike is a different story.

"A fast bike on flat roads is about rigidity and aerodynamics, not weight." The key word here is flat.

ZachS

did you measure how much your speed/time actually changed?

Jakey

Bicycling magazine did a study a while back... the conclusion was given the same effort, for every pound you shave, you gain 6 seconds on a 20 minute climb. My bike weighs about 18 seconds slower than the pros ride.... The comfortable ride I have is more than worth the few seconds I might gain....especially since I don't race.

531Aussie

really? Every third thread on this forum about someone looking for the lightest wheels on the plant, and every fifth thread is about someone wanting to get their bike uner 16lbs. You KNOW these people think this will make them faster

531Aussie

yeah, but acceleration means more to these guys than ANYONE! If they don't get from ZERO mph (not 15mph, not 18mph...ZERO!!) to their pursuit speed as quickly as possible, they're screwed!!



Theo Bos is a sprinter (his BT is 17.5lb), and many of the sprinters use the same frame, with most using steel bars.

I bet Nothstein's criterium bike was NOT 15lbs!!!

GuitarWizard

My 5200 in "riding form" (2 full waterbottles, seat pack) weighs in at around 24 pounds.....

svbiker

or you could have light and aero=cervelo!

Tom Stormcrowe

Marked distance, granted, it was just a supershort 100 meter sprint, but I hit my max cadence and a higher ground speed faster on the lightweight. That's the only standard I was judging by, the acceleration to top speed and apparent effort over a flat course with warm muscles. Gearing was comparable, by the way. Like I said, it felt like I was rocket propelled! As to how the bike would ride on a long ride? I don't know! It felt pretty comfortable ergonomically speaking. I've always ridden steel frame and this was my first time on an Aluminum frame (No kiddin'!). I just wanted to get a feel for what my new road bike would feel like (Well, newto me!) with the 531 frame. It's about 1.5 pounds heavier than the Giant, so should be roughly similar.

zacster

Do you carry lead weights in your seat pocket? A 5200 stock can't weigh more than 18 pounds, probably a little less. That's six pounds of stuff.

shokhead

Thats the truth. Just ride more and your bike will feel lighter without spending a buck.

Duke of Kent

Those guys are also riding full disc front/rear wheels in a lot of cases. Particularly the last couple of guys, who are members of the 4k Team Pursuit. They're concerned about aerodynamics and stiffness, not weight. If these guys were climbing the Galibier, Alpe d'Huez, or the Izoard, you better believe they'd want sub-16lb bikes. Horses for courses, my man. Don't be naive enough to think that they haven't carefully considered the pros and cons of their bikes, and wouldn't change them if the situation called for it.

slide

Interesting for me a noob all the wisdom here. The folks on this thread saying that mass is irrelevent in a bike are clearly way ahead of the guys who make the bikes for the G d Italia or the TdF riders. Those fools think mass really does matter. Maybe they need to learn a bit from the guys here on those 28 lb bikes.

ZachS

i don't think anybody's saying that mass is irrelevant. what people are saying is that the difference in mass between a 15 pound bike and a 23 pound bike is irrelevant for most riders in most circumstances. which it is.

most people in most circumstances ≠ folks who are paid to ride up hills faster than other people

DrPete 

"Those fools" have a slightly different set of circumstances.

1. They're trying to shave MINUTES off of races that last WEEKS.
2. They have unlimited cash (and that's an important one).
3. Their bikes are being ridden by athletes who produce consistently huge amounts of power so a tiny weight difference is actually noticeable.
4. Those riders also have NOTHING extra on their bodies that would negate a weight savings on the bike.

So, for you or me, the normal human riders of the world, is it worth it to spend $7000 to shave 2 pounds off my frame when the motor has 10 extra pounds sitting on it?

I'm just glad it doesn't cost that much for ME to lose weight-- $1500 for my Flyte, a few hundred for my OCP helmet and clothes, and any excuse to go out and ride.

DrPete