Ed in Toronto

I find that when I'm coasting down a long hill along side carbon fiber bikes also coasting, that my steel bike starts to increase speed over the carbon fiber bikes. I have to keep touching my brake so that I don't put my front wheel into their rear wheel. I don't like constantly touching the brakes down a long slope, so I eventually duck right down with my chin almost touching my stem for more wind resistance and pass a little quicker, to get it over with.

Or is something else going on, like I have less drag from my position in the saddle over them. They have dropped handle bars too, so I don't know. But then again, people with carbon bikes ride the hoods, and down a long hill I'm on the drops. But on the other hand they slam their stem down, and I have mine up somewhat. As you can see, I've been thinking about it, and maybe over thinking it. I don't like passing Cervelo bikes going down a long hill because I feel like their thinking, look at the guy with the old bike, he wants to be a champ and pass us, and the only time he can do that is going down a hill when we're taking a break and coasting.

AlbertaBeef

Heavier riders go downhill faster. Bike weight + rider weight applies here... If you're the same weight but your bike is heavier - you go downhill faster. Same with wheels... heavier wheels go down faster.

If it's about weight, unless the guy on the Cervelo is a moron he knows you're passing him because you're heavier, and he also knows he'll catch you AND pass you on the uphill.

BTW as both a clydesdale and a steel-bike rider I make it a rule to pass everyone downhill. Period. In a group I work my way to the front of a peloton before a climb, usually drop to the end of the peloton at the top (hopefully not totally dropped) then stay with them (or pass them) on the down...

Puget Pounder

Lots of unfounded assumptions here. Too many variables here.

AlbertaBeef

If you mean my assumptions were unfounded - Yes, I made some assumptions...

I assume that 1) you have similar rolling resistance and 2) your hubs are as smooth as the next guy ... then if you're heavier and even remotely aero you're simply going to go faster downhill.

I'm one of the heaviest guys in my club, and there is nobody that touches me downhill unless they can get in my draft. Even then most don't have the nerve to maintain the speed.

The truth is gravity works.

cb400bill

Unless he can't hear you. We had a new guy on our club ride last week. His Cervelo carbon bike frame was LOUD. Louder than any bike I have ever heard.

DVC45

Exploded?

AlbertaBeef

The frame was loud? Or was he on those crazy loud fulcrum wheels? When coasting those freehubs are scary loud... I've never heard wheels louder than fulcrums...

Puget Pounder

Hold your horses here. I'm not an idiot and I know more physics than the average person. I am talking about the original post. What does a lugged steel bike have to do with going faster than a carbon bike? Absolutely nothing.

The truth is, I never said gravity didn't work, but yes... it does work.

Smoother hubs, bearings, aero dynamics of the rider and components, wheels, weight, tires, tubes, rider position, helmet, etc... Yeah, a lot of things we can look at.

AlbertaBeef

Wasn't implying you were an idiot... I think you took what I said out of context... I was simply clarifying my statement, not taking offense at yours.

Yup, every single one of those things plays a factor. For me, as a big guy (even lean I have a 48" chest - people love to draft off me) I found that aerodynamics plays the biggest factor... I played around with several positions for downhill until I found one that was aero, comfortable AND allowed me enough control to feel safe at speed ... Positioning alone adds 10-15km/h to my downhill speed on a long stretch.

Many smaller riders will grip the drops, shift forward, drop their hips/buttocks below the saddle just over the top tube and put their shoulders inside their handlebars - but I don't fit that way, so I favored the butt-back, hands on the inside/tops of the handlebar forehead to the stem approach. Heck, just ensuring your crankarms are parallel to the ground gets you another 1-2km/h in speed...

If the guys he's with are on the hoods and he's in the drops... that gives him a huge advantage alone.

cb400bill

No, not exploded. It just sounded like an echo-y loud hollow plastic-y type of sound. Hard to describe, I guess.

Could be, I don't know. I didn't check what wheels he was riding. If he is there this Monday, I'll check.

leftthread

Ed in Toronto

It might be aerodynamics, I'm not sure, was wondering if there is any concrete knowledge about weight of bikes effect on going down a hill.

I'm 6'2" and weight 195lbs.

I do ride the drops down a long hill, but my stem is 2' 1/2" up from being slammed.

The carbon bikes I pass seem to have woman and shorter lighter men, but then again I'm kind of tall.

calamarichris

The answer you seek resides within your question.

Also, the weight difference between frames is a fraction of the weight difference between the engines.

oldskoolwrench

To the OP...

As everyone has said there are many variables to explain why, but personally I wouldn't worry about it or let it bother you,
especially what the other riders think. Pick 'em off one by one on the descents and have fun doing it. If they pass you on
the climbs, so what? Tell them you were enjoying the scenery; life's too short to appreciate the finer things, right?

I bet you were looking for a more technical response; I went for the more 'sociological' one.

aixaix 

It works on all things equally, regardless of mass or density. You may be the heaviest and fastest downhill rider, but it isn't because gravity is treating you any differently than anybody else. Wind resistance & rolling friction are the variables here.

thenomad

the weight difference may be along the 3-5 lb range, so hubs, aero and body weight make up more. If you have empty bottles and they have two large full ones then all is equal.

if you are drafting you certainly will catch them unless you are a feather.
If you put your chin on the stem then you'll decrease wind resistance for more aero and go faster etc.

Maybe

Reynolds 

And what about TIG welded steel bikes?

iab

That's called drafting. Less wind resistance = increased speed.

thenomad

Easy answer = slower.

Why? = More 'ugly' to overcome

Amesja

Mr. Galileo was correct...

-How 'bout that?

thirdgenbird

X2

Stay glued to their wheel long enough and you will get a false sense of your ability. I've been on group rides where I felt great but instantly ran out of gas when I went out to pull.

AlbertaBeef

That is true, but without gravity there would be no acceleration, thus no speed difference.

AlbertaBeef

Obviously they have even MORE of an aero advantage...

jettore

OP - Are you passing riders in a group you are riding with or are you talking about just passing random people you come up on while riding? It isn't really clear in your post.

Ed in Toronto

Just random people. I'm riding around in the city, and you don't see groups there.