How important is weight?

While I know this sounds like a silly question, and I know it does make a difference. My question is how drastic is this difference? I am a clydesdale whom is used to 40+ pound all steel bikes most cyclists can't lift with one arm.

 

Depends. IMO it can be hugely important for the feel of the bike, and the ride experience. Even though, on a fairly flat course it usually won't really mean much in time/speed.

 

It's hard to "isolate" just the weight factor on bikes.

Maybe a good way to do that is to ride a bike twice. Once as it is and once loaded with 2kg of water or something.

But if you compare two different bikes with different weight there will be other factors involved too.


For example, a heavier bike made of CF will probably (depends on tube shapes etc) be more rigid then a lighter bike also made out of CF. The same probably applies for Aluminium.

But that is for the -same- grade of CF and Aluminium.

But if you compare bikes of different materials then it's even more complicated.


I did a test once. I Test-Rode a CF bike of similar intended use with mine, in the same course that I usually take when I am out doing some km's. The CF bike climbed better then the Alu bike, even with a smaller gear on the back. It also accelerated faster. On the descents I did not feel such a difference and as for "keeping speed" the carbon bike seemed that it was more susceptible to slow down due to road friction.


Maybe even more important is how rigid the bike is. Then other things for consideration can be how true the wheels are, the ride position etc...


Btw it's funny how fat-people always want a light bike. They can probably save about 5000 euro by just losing 3 kg.

 

That's part of what I was wondering. I'm fine with my all steel "boat anchors" I ride now, but was wondering if the extra $500+ USD was worth the difference in the ride. As you may have guessed, I was expecting a response from "the common cyclist" whom typically favors a wormy guy with a head the size of my belly. ;-) That's not what I want for myself though.

 

Extra 500? Maybe add another zero on that figure.

My bike is about 1000USD. The bike I tried was about 4000...

Was it riding better? Yes. Was it riding 3000USD better? No...

Even the Ultegra drivetrain although nicer then my bottom of the barrel 2300-Claris combination didn't feel like it worth the extra 2000...


Even scarier, if I crashed the CF frame, (or more likely -when- I would crash it) that would probably be alot more serious then crashing the fat walled Alu frame.


As they say for LOTUS cars... LOTUS = Lots Of Trouble Usually Serious.


Alu is nice for crashing. Even steel frames which are more expensive have thinner sidewalls and might be more prone to serious damage from a crash.

Ofcourse I would want a CF bike, but the place I live is not very CF friendly... and I am still away from mid-life crisis that would excuse such a purchase. I also don't race on serious time saving demanding events.


Maybe a -nice- Alu bike, like a Caad10 or a E5 Allez, or a nice CX Ridley would be great in doing alot of miles in a stiffer frame then a Steel sport bike... The steel bike would probably last longer then the Alu frames though, but would probably not be as "sporty", (in terms of stiffness probably). If not crashed. Which happens, alot.

There are also Titanium frames now but I haven't got too much info on those and the choices are much more limited then Alu and CF.


Then you could also keep a crazy CF race bike just for the races... If you race... Or for these really nice rides.

 

I kinda expected that looking at what I'm seeing at www.bobsbikes.com and www.cahabacycles.com, and their "entry level" on/off road bikes are $750 USD, vs. the $250 Wally-World bikes I have (Black River Canyon, Pacific Cycles, Mongoose, etc.) though I paid $23 and $17 for mine. I'm also wondering about the difference between my bikes vs. those bikes, as I can't tell much difference in the parking lot, and it's amazingly flat there to be pearched on the side of Red Mountain. I'm 225 pounds. We'll say my bike is 40 pounds. That puts me riding around 265 pounds on the tires. If I borrow a buddy's similarly equipped aluminum or carbon bike and ride from Samford to The Zoo, and then to Bob's Bikes for a part, then return to Samford the same way, how will this translate to the ride experience as I go, assuming we both have similar gearing and solid frames?

 

Dude...

Some people can't feel the difference from a Hi-Ten MTB frame and a CF Road Racing frame...

How many miles have you got on your belt?

What kind of improvements do you expect from a new bike?

 

If weight were not a significant factor the Tour and Giro would be won on beach cruisers...equipped with Campy Super Record EPS, of course.

 

"Tonight's the night that we got the truck

And ride, ride how we ride. "

 

If my buddy's bike weighs 20 pounds, that would put me at 245 pounds on the wheels vs. 265 pounds now. I'm not expecting all that much right now, but I do know a 20 pound weight sure does get heavy when I carry it across a football field. ...then again, am I carrying the bike or riding it?

 

You are riding the bike... More about the physics of it here (nice book, you can also find it online):

Also on Shelon Brown's website there is an article about upgrading old road bikes:


Yes, 10kg is alot of difference. It's a whole bike actually. Things that would change would be:

1. Easier braking. But then again, an 18kg bike is probably equiped with disc brakes or something whilst the 9kg bike is probably equiped with road calipers.
2. Easier climbing.
3. Easier acceleration.


If it's 18kg, there is probably not much point in discussing about stifness, shock absorption etc...


Is your bike really 18kg? How much does it weight without panniers, water bottles etc?

A new good - ish steel bike weighs around 10kg as a new Aluminium road bike. Less is possible with even better components etc.

I kinda doubt that a bike can weigh 18kg unless it's really old with some seriously heavy components or if it is a really heavy mountain bike, which again is usually not more then 16kg...


Have you got a pic?

Btw, bike shops give out bikes for test-rides. Why not try one?





Upgrading Older Road Bicycles:

http://sheldonbrown.com/upgrade.html

 

On flat ground, the wheels and tires are "carrying" the weight, not you. The only thing extra weight adds is extra rolling resistance, not that big a deal depending on your tires. The extra bodyweight will make it harder for you to accelerate, and also harder for you to shed the excess heat in hot weather, but it really won't slow you a lot....just a few extra watts output needed.

Everything changes when you start climbing though. At low speeds, steep hills, your speed will be roughly proportional to your total (body plus bike) weight. That means on a climb where you're working hard to maintain say 5 mph, saving 20 lbs on the bike will get you about 5.4 mph for the same power output....just doing the ratio. That's the difference between keeping up and being passed pretty easily.....Not everyone cares of course....

 

That last sentence was intended to be a funny. ...though at this point, I'll start fussing over feet per minute once I get ready to start racing. For now, I'm more concerned with making my bike both a tool and a toy. Some things are still highly experimental. Hmmm... I wonder if I can pull a plow or a bush hog... :tongue2: I probably need to stick to hauling.

 

In that case, maybe an aluminium racer modified for commuting? (Race bike with rack, fenders and wider tires?)

 

Volnix, I have that Bicycling Science book you picture. Agree it's a good one. It covers a wide range of subjects related to bike physics, engineering and riding. It's a bit dated now, but still would highly recommend it.

 

Yeah it's old... Maybe they'll make a new one.

But yeah it covers alot of topics which are still the same, even after the invention of "Pinarello's Toray Carbon".

 

I am going to equip a "short frame" with a rack and aero bars as soon as I rebuild the rear wheel. It already has 26x2 inch tires. Brakes suck, but I can fix that.

 

Alot of people do that... Getting a MTB and then wanting to go faster, getting new wheels, tires, bars etc.

Another idea would be to get a road frame. Either cyclocross or road race / endurance and then make it -slower- by equiping fenders, racks and wider tires.

 

That's sorta what I'm doing with my short frame Volnix. It came with 26x2 inch tires, but I will want to change the 5 speed Falcon to a 7 (or so) Shimano Megadrive. I also have to replace the back wheel since I Bogardted it for my nite bike. It's also much lighter, so I may put the Big Pig rims from my full floater (a very heavy frame) on it and the short frame rims (which themselves are heavy) on the full floater. All three bikes have 26x2 inch wheels with different treads. I'm wanting a dynamo for my nite bike, so I'm using that as an opportunity to specialize each bike more.

 

The 5 speed! - What? A Shimano 7! - What? MTB? Don't look at it!!!!!!