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


Go Back   > >

Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 11-18-13, 12:26 PM   #26
slcbob
bored of "Senior Member"
 
Join Date: Oct 2007
Location: MD / metro DC
Bikes: Cross-Check/Nexus commuter. Several others for various forms of play.
Posts: 1,101
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
I think you should upgrade your front wheel, too. But first, upgrade your breaks so that you can handle the extra burst of speed.
slcbob is offline   Reply With Quote
Old 11-18-13, 04:10 PM   #27
AusTexMurf
Senior Member
 
AusTexMurf's Avatar
 
Join Date: Dec 2012
Location: South Austin, Texas
Bikes: 2010 Origin8 CX700, 2003 Cannondale Backroads Cross Country, 1997 Trek mtn steel frame converted commuter/tourer, 1983 Univega Sportour, 2010 Surly LHT, Others...
Posts: 805
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 19 Post(s)
Quote:
Originally Posted by Sasquatch. View Post
I have noticed that my bikes feel slower when my spokes are loose. I think the wheel has more spring/flex to it and absorbs more energy much like a tire with low PSI.
+1
Spongy.
AusTexMurf is offline   Reply With Quote
Old 11-18-13, 08:33 PM   #28
Andrew R Stewart 
Andrew R Stewart
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
Posts: 7,220
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 219 Post(s)
Quote:
Originally Posted by AusTexMurf View Post
+1
Spongy.
Not sure I agree. I haven't seen studies about spoke tension effecting efficiency. But I do know the difference between feed back and efficiency. That so many people don't is why there's the misbelief that fatter tires are slower then skinny ones. Slow reaction is not less speed. Andy.
Andrew R Stewart is offline   Reply With Quote
Old 11-18-13, 08:51 PM   #29
rebel1916
Senior Member
 
rebel1916's Avatar
 
Join Date: Aug 2011
Bikes:
Posts: 2,992
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by dynodonn View Post
I decided to put the hammer down.
I believe the phrase you were actually looking for was "drope the hamer".
rebel1916 is offline   Reply With Quote
Old 11-18-13, 09:06 PM   #30
JohnJ80
Senior Member
 
Join Date: Feb 2011
Location: Minnesota
Bikes: N+1=5
Posts: 2,882
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 62 Post(s)
I believe the phrase you were looking for when you helped him find the phrase he was looking for was "drop the hammer."
JohnJ80 is offline   Reply With Quote
Old 11-18-13, 09:16 PM   #31
rebel1916
Senior Member
 
rebel1916's Avatar
 
Join Date: Aug 2011
Bikes:
Posts: 2,992
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by JohnJ80 View Post
I believe the phrase you were looking for when you helped him find the phrase he was looking for was "drop the hammer."
You couldn't possibly be more mistaken.
rebel1916 is offline   Reply With Quote
Old 11-18-13, 09:47 PM   #32
ThermionicScott 
Gratuitous glib and snark
 
ThermionicScott's Avatar
 
Join Date: Aug 2011
Location: CID
Bikes: 1991 Bianchi Eros, 1964 Armstrong, 1988 Diamondback Ascent, 1988 Bianchi Premio, 1987 Bianchi Sport SX, 1980s Raleigh mixte (hers)
Posts: 14,099
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 418 Post(s)
Quote:
Originally Posted by JohnJ80 View Post
I believe the phrase you were looking for when you helped him find the phrase he was looking for was "drop the hammer."
Incorrect. This is BF, it's "drope the hamer".
__________________
Quote:
Originally Posted by chandltp View Post
There's no such thing as too far.. just lack of time
RUSA #7498
ThermionicScott is offline   Reply With Quote
Old 11-19-13, 04:15 AM   #33
Medic Zero
Senior Member
 
Medic Zero's Avatar
 
Join Date: Apr 2011
Location: Vancouver,Washington
Bikes: Old steel GT's, for touring and commuting
Posts: 2,195
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 7 Post(s)
Quote:
Originally Posted by Andrew R Stewart View Post
Not sure I agree. I haven't seen studies about spoke tension effecting efficiency. But I do know the difference between feed back and efficiency. That so many people don't is why there's the misbelief that fatter tires are slower then skinny ones. Slow reaction is not less speed. Andy.
Well, I haven't done any studies, but I've killed more rear wheels than I care to count. One thing I started noticing was that it felt like it was taking more and more energy to climb the hills I have to climb every day. Then, inevitably the wheel would finally really show me that it was toast by starting to break spokes. As soon as I put in a new, properly trued wheel, it was amazing the difference I felt. It was like the difference between heading out on my commute on a day where I got enough sleep and had a decent breakfast versus the commute home after working an overnight shift and not having eaten for hours.

Makes sense to me that a wheel that is mushy from all the spoke tension being gone would rob you of a lot of the energy that should be propelling you forward.

My zwei pfennig anyway.
Medic Zero is offline   Reply With Quote
Old 11-19-13, 09:34 AM   #34
Andrew R Stewart 
Andrew R Stewart
 
Andrew R Stewart's Avatar
 
Join Date: Feb 2012
Location: Rochester, NY
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Raleigh Pro, Trek Cycle Cross, Mongoose tomac ATB, GT Bravado ATB, JCP Folder
Posts: 7,220
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 219 Post(s)
Medic Zero- In no way am I saying that a loosely spoked wheel is right or what we want. The condition will have other consequences (broken spokes, rubbing brakes, etc) that are not conducive to finishing a ride quickly.

But if put in isolation of these other issues does a "soft" wheel retain energy? I'm just not sure how much looseness creates how much energy gain (as in how much energy is transfered from the forward rolling of the wheel to friction of the spokes rubbing against each other or against the hub/rim holes).

Once again, I maintain that most people confuse the issues at play when talking about what is perceived VS what is actually going on. Andy.
Andrew R Stewart is offline   Reply With Quote
Old 11-22-13, 08:03 PM   #35
old's'cool 
curmudgineer
 
old's'cool's Avatar
 
Join Date: Dec 2009
Location: Chicago SW burbs
Bikes: 2 many 2 fit here
Posts: 3,777
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 34 Post(s)
I have no analysis to back it up, but my gut feel agrees with Andrew R Stewart's post #34 . I.e., by the time the spokes are loose enough to result in significant energy loss, you're facing other, more immediate problems, notably high risk of tacoing a wheel.
The situation you want and is the design intent of a spoke wheel is that the static tension is high enough that the variable tension due to load reversal on rotation is a reasonably small fraction of the static tension, (and preferably less than 20% of the UTS so that we are within steel's fatigue limit, i.e., assuming steel spokes).
But unless variable tension is approaching 100% of static tension, I see no great absorption of energy through this mechanism.
__________________
Geoff
"I think that I think, therefore I think that I am"
old's'cool is offline   Reply With Quote
Old 11-23-13, 06:35 AM   #36
slcbob
bored of "Senior Member"
 
Join Date: Oct 2007
Location: MD / metro DC
Bikes: Cross-Check/Nexus commuter. Several others for various forms of play.
Posts: 1,101
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
It's easy to forget that the only way the whole damn contraption (you + bike + Fredly gear + etc.) is connected to the road via the tires+rims is through the spokes -- those flimsy little things. The hubs don't hover on their own, they are held up by the spokes and all the forward/backward force of accelerating and braking is translated into lateral and rotational forces in the wheel that are transmitted through them, too.

Once that is in perspective, it should become a bit easier to ponder that lousy spoke tension just makes for a sloppy ride with wasted energy going everywhere, +/- causing problems in the spokes/wheel. The numbers that were kicked around here seem to be for a pretty sloppy wheel, YMMV, but they're not wacky.

Ever try running in soft beach sand, vs. hard sand (say at water's edge) vs. pavement? You won't be setting a personal best in the sand. Loose spokes on a bike are like soft sand for a runner. Until they break, then they're worse.
slcbob 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 11:18 AM.