Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Galleries NEW FAQ Contact About
It is currently Sun May 01, 2016 9:33 am
Recently the board software has been updated and there are some known bugs/failures:
- Avatars are currently not being displayed
- Tapatalk connection is currently broken

Those bugs will be fixed ASAP (next few days) as they are unfortunately more serious than expected.

If you find more errors please post it here: http://weightweenies.starbike.com/forum/viewtopic.php?f=7&t=139062

All times are UTC+01:00

Post new topic  Reply to topic  [ 5 posts ] 
Author Message
PostPosted: Thu Apr 10, 2014 1:05 pm 

Joined: Wed Mar 17, 2010 12:04 am
Posts: 103

I've got a powertap that I switch between two bikes, my training bike and my race bike.

I commute on my training bike and use cheap SPD pedals and heavy shoes. It dawned on me the other day that my power readings might be different between bikes as power is being measured at the hub, and there are fairly significant differences between the shoes / pedals / drivechain on both bikes.

My SPD shoes are over 300g each heavier than my race shoes, and the weight difference between my bottom of the range SPDs and my Dura-Ace's must also be significant.

But then I also have the weight advantage on the down stroke......

I know this is going to be marginal, but thought it would be interesting to discuss whether there is an impact?

PostPosted: Thu Apr 10, 2014 1:16 pm 

Joined: Tue Sep 20, 2011 12:54 pm
Posts: 395
Location: Haines, AK - Temporarily
I think you could easily have a different drive train loss between the two bikes that could account for an equal/more loss.

PostPosted: Thu Apr 10, 2014 6:32 pm 

Joined: Thu Feb 27, 2014 8:59 pm
Posts: 159
Location: Kingston, Ontario, Canada
Your race bike likely takes less energy to ride at the same pace.
While it is a torque reading and im not sure how cycling systems use it, you will need as much energy to pull the heavy pedals up as it (the weight) helps going down.

PostPosted: Thu Apr 10, 2014 6:44 pm 

Joined: Sat Aug 29, 2009 4:30 pm
Posts: 1861
Heavy shoes can really increase your output power, but only if you take your foot off the pedal during each "upstroke", So the weight of the upstroking shoe doesn't work against the gravity pulling down the downstroking side. Then you have to switch feet really fast for the next half of the crank rotation.

It takes skillful coordination.

PostPosted: Sat Apr 12, 2014 2:17 pm 

Joined: Tue Aug 03, 2010 6:29 pm
Posts: 593
I've noticed, although I can't say with 100% certainty, but I had about a 5 Watt difference in 20 min power when switching between shoes.

The lower reading came with a pair of Sidi Energy, heavy, nylon sole etc etc and the higher power output with a pair of DMT Radial, so, stiffer, carbon sole, lighter.

I don't think the weight had anything to do with it, probably the stiffness, if anything. I'm using a Quarq though, so I wouldn't see any drivetrain losses which are probably relevant in your case as well.


Do you suffer more when you train, or cannot train?

Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 5 posts ] 

All times are UTC+01:00

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited