Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Clydesdales/Athenas (200+ lb / 91+ kg) Looking to lose that spare tire? Ideal weight 200+? Frustrated being a large cyclist in a sport geared for the ultra-light? Learn about the bikes and parts that can take the abuse of a heavier cyclist, how to keep your body going while losing the weight, and get support from others who've been successful.

Reply
 
Thread Tools Search this Thread
Old 06-22-11, 05:46 AM   #1
hobkirk
Retired dabbler
Thread Starter
 
hobkirk's Avatar
 
Join Date: May 2010
Location: Acton, MA (20 miles west of Boston) - GORGEOUS cycling territory!
Bikes: 2007 Specialized Roubaix Elite Triple - 1st ride = century 9/19/2010 , Ultegra
Posts: 683
It'is all about the climbing - esp. for us - Lose 440 yds going up, gain 15 doown

I don't do much in this forum even though I fit the definition - I'm currently 233# at 6'2" - much too heavy by any chart and vastly too heavy for this sport. I hope you find the following info interesting.

Ascent

When I started riding, I used to ask my only cycling friend a lot of questions. His most memorable quote was "it's all about the climbing." This from a guy who chose to ride centuries (100 miles) over the Kangamangs pass in the White Mountains.

But I didn't just harass friends, I also read about cycling.

Joe Friel depressed me with his claim that:
  • Every kilogram costs 3 seconds over a kilometer on a 5% ascent

I weigh 38# more than my minimum goal, 48# over my preferred goal. If I round that to 20 Kg (1 Kg = 2.2#), that means my fat costs me 90 seconds over one mile at 5% (I think "miles," not "kilometers").
  • At 10 MPH, it's 0.25 miles.

No wonder I get dropped on group rides at every climb.

Coasting

Gravity is a fat rider's friend on downhills, but the advantage is a small fraction of the climbing penalty. Based on a year of riding, almost entirely with fit people, I would guess my downhill advantage is 1-2 MPH - it's a subtle edge. Downhill speeds are faster, of course, and I am using educated guesses for average descent speed.
  • 30 MPH would gain 9 seconds (15 yards, roughly 0.01 miles) over 28 MPH over a mile. Argh!

Net
  • Lose 0.25 miles going up, gain 0.01 miles going down

-----------

On a recent group ride there was a very long and very steep hill around the 25 mile mark. The fit riders (there are very few fat riders in my cycling clubs) had grouped at the top. I yelled "curse you skinny people" as I rode by. They should grasp my sarcasm by now. I kept going because I knew they would catch me on the next climb.

-----------

Feel free to point out any errors! Have a great ride.
hobkirk is offline   Reply With Quote
Old 06-22-11, 06:39 AM   #2
volosong 
Senior Member
 
volosong's Avatar
 
Join Date: Apr 2011
Location: Antelope Valley, SoCal
Bikes:
Posts: 2,712
Sheech! I knew I couldn't climb, but didn't know it was that bad. The new bike has helped a lot, but it looks like I need to get my weight down to where your goal is. I am 6'3", (well, actually 6' 2 and 3/4", depending on the time of day), and currently holding at 206. I too would like to maintain 195, and would really feel comfortable at 185. Got there a few years ago, but a heavy work schedule and using food as an emotional comfort "outlet" took me back up to 215 or so earlier this year. I seem to be holding steady at 205-206 the past few weeks.

And ... uugh! I don't like hills, but that seems to be the best way for us to burn off the excess calories. Oh, and going downhill? I'm a "chicken" on the downhills. An experience with the "death wobble" has scared me enough to keep my coasting speeds below 35 or so. On flats, no problems ... just downhlls.

Thanks for your analysis.
__________________
Deut 6:5

---

"Ha ha! You fool! You fell victim to one of the classic blunders - The most famous of which is 'never get involved in a land war in Asia'".
- Vizzini during his "battle of wits" with the Man in Black
volosong is offline   Reply With Quote
Old 06-22-11, 08:26 AM   #3
Homeyba
Senior Member
 
Homeyba's Avatar
 
Join Date: Jul 2009
Location: Central Coast, California
Bikes: Colnago C-50, Calfee Dragonfly Tandem, Specialized Allez Pro, Peugeot Competition Light
Posts: 3,370
That's pretty much it. Us big guys have to be stronger to go just as fast up hills as the little guys. The advantage of being bigger/stronger is that with our strength we can also put a serious hurt on them in the flats.
Homeyba is offline   Reply With Quote
Old 06-22-11, 08:50 AM   #4
Mithrandir
Senior Member
 
Mithrandir's Avatar
 
Join Date: Jun 2011
Location: Buffalo, NY
Bikes: 2012 Surly LHT, 1995 GT Outpost Trail
Posts: 2,400
Quote:
Originally Posted by Homeyba View Post
That's pretty much it. Us big guys have to be stronger to go just as fast up hills as the little guys. The advantage of being bigger/stronger is that with our strength we can also put a serious hurt on them in the flats.

I'm noticing this. I can't climb worth crap, as I discovered much to my chagrin last week, but on level ground I can scream by guys who are easily 200 pounds lighter than me.

I'll keep tackling hills for practice, but these calculations make me slightly disheartened
Mithrandir is offline   Reply With Quote
Old 06-22-11, 08:56 AM   #5
engstrom
Getting a clue
 
engstrom's Avatar
 
Join Date: Jul 2010
Location: Plano, TX
Bikes: 2010 Trek Madone 4.7, Diamondback Wildwood
Posts: 415
I'm fortunate that I'm in a very big bicycle club. As a result we have 9 different Saturday morning rides (at 9 varying levels of speed and distance). The ride I do has several clydes. Pretty much all of them are faster than me up the hills, but I'm getting better. And eventually I'll lose 50 lbs. (already lost 30) and be down to my goal weight. Between weight loss and continued training I figure I'll be great on those hills (of course by then I'll be riding one of the more advanced rides and still be slow compared to the rest of the guys ).
engstrom is offline   Reply With Quote
Old 06-22-11, 09:59 AM   #6
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Bikes:
Posts: 13,424
Quote:
Originally Posted by hobkirk View Post
Gravity is a fat rider's friend on downhills, but the advantage is a small fraction of the climbing penalty. Based on a year of riding, almost entirely with fit people, I would guess my downhill advantage is 1-2 MPH - it's a subtle edge. Downhill speeds are faster, of course, and I am using educated guesses for average descent speed.

  • 30 MPH would gain 9 seconds (15 yards, roughly 0.01 miles) over 28 MPH over a mile. Argh!
I think if they're both on the same bike, a skinny person tucked in will go down the hill faster than a hefty person riding on the tops. Remember, aerodynamics is the only reason a bowling ball falls more quickly than a feather.
Seattle Forrest is offline   Reply With Quote
Old 06-22-11, 09:15 PM   #7
nkfrench 
Senior Member
 
nkfrench's Avatar
 
Join Date: Aug 2008
Location: Fort Worth, TX
Bikes: 2006 Specialized Ruby Pro aka "Rhubarb" / and a backup road bike
Posts: 1,831
Quote:
Originally Posted by Seattle Forrest View Post
I think if they're both on the same bike, a skinny person tucked in will go down the hill faster than a hefty person riding on the tops. Remember, aerodynamics is the only reason a bowling ball falls more quickly than a feather.
It's not an exact analogy. We're riding downhill, not dropping off cliffs. The physics are a little beyond me, but clydes have more potential mass at hilltop. athenas too.
nkfrench is offline   Reply With Quote
Old 06-23-11, 09:52 AM   #8
jgalak
Member
 
Join Date: May 2011
Location: Long Island, NY
Bikes: Bianchi San Remo, Gary Fisher Marlin
Posts: 49
Quote:
Originally Posted by nkfrench View Post
It's not an exact analogy. We're riding downhill, not dropping off cliffs. The physics are a little beyond me, but clydes have more potential mass at hilltop. athenas too.
I believe you mean potential energy, not potential mass. From a pure potential energy becoming kinetic energy, the mass is irrelevant - yes, a heavy rider has more potential energy at the top of the hill, but he also needs more kinetic energy to move at a given speed when at the bottom of the hill: The formula is Potential energy (at the top) = Kinetic energy (at the bottom). PE=mgh, KE=.5mv^2m so mgh=.5mv^2 (m is mass, g is acceleration due to gravity, h is height, v^2 is the velocity squared) - the mass term cancels out. This would be enough to describe the behavior of items falling in a vacuum.

However, there are two major factors that complicate things - we don't ride in a vacuum, so we need to handle air friction, we aren't falling straight down, so we have to account for a much more complex rolling movement.

Air friction is insanely complicated to actually compute for something as weird-shaped as a rider on a bike, but the biggest factor is frontal area - a smaller (or more tucked in) rider will have less air friction than a larger one. No help to us Clydes.

The rolling movement is a bit beyond my long-ago and nearly-forgotten physics knowledge, but I don't think there's any help to us big guys there either - though I may be wrong.
jgalak is offline   Reply With Quote
Old 06-23-11, 10:23 AM   #9
Seattle Forrest
Senior Member
 
Seattle Forrest's Avatar
 
Join Date: Mar 2010
Location: Seattle, WA
Bikes:
Posts: 13,424
Quote:
Originally Posted by nkfrench View Post
It's not an exact analogy. We're riding downhill, not dropping off cliffs. The physics are a little beyond me, but clydes have more potential mass at hilltop. athenas too.
Potential mass? We're either there or we aren't; it's not like another 50 pounds will materialize on our way down the hill.

You're right that we're rolling, and not free-falling, and what that means is that slick tires will get you down the hill faster than knobbies. That's going to be good for a few miles per hour. Honestly, I think switching from Gatorskins (not Ultras) to GP4000s got me about 1 or 2 mph going down a hill at around 30 mph, because they have less rolling resistance. I could be off, but that's my gut feeling.

But, really, the difference is we aren't in a vacuum, so we have air resistance. And it goes up with the cube of your speed, for whatever frontal area you have. This is why the bowling ball falls more quickly than the feather, not because of their weight. Doing the aero-tuck so that less of your body is pushing against the wind will help you speed down the hill more than gaining weight ever will.

None of this changes the point in the OP, that hills slow Clydes down, compared to equally strong but skinnier riders. Oh well.
Seattle Forrest is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 11:01 PM.