Unicyclist Community

Go Back   Unicyclist Community > Unicycling Discussion > General Unicycling Discussions

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 2015-07-13, 03:59 PM   #106
unibokk
Unicyclist
 
Join Date: Feb 2013
Posts: 955
Yep, those countless micro adjustments often require backward pressure on the pedals which over one hundred miles would be costly.

Endurance cycling is helped greatly by smooth motion.
unibokk is offline   Reply With Quote
Old 2015-07-13, 04:18 PM   #107
bouin-bouin
Didier
 
bouin-bouin's Avatar
 
Join Date: May 2008
Location: France in Europe (Le Chesnay - Yvelines)
Age: 52
Posts: 777
Quote:
Originally Posted by tholub View Post
Corbin Dunn, another of the world's fastest unicyclists, runs at 32psi.

Bicycle Quarterly has done a bunch of research on rolling resistance and pressure for bikes, and found that in real-world conditions, the conventional wisdom that higher PSI means less rolling resistance is actually wrong. The bump absorption of the lower-pressure tire more than makes up for the energy of the additional tire deformation. That's probably even more true for unicyclists, because micro-adjustments to correct our balance because we hit a small bump are pretty expensive in this context.
That's correct at a certain point of very high pressure but 30 PSI is very low ! Roger who is also quite a fast rider uses much higher pressure thant this !
So ?
__________________
http://monocycle.info
http://www.leblogdumonocycle.fr/
CITY XTP 26", MUNI KH26" & KH29", ROAD Oracle 32" and KH36"
my goal : a 3 geared 29" to have only one uni for all kind of rides :-)
bouin-bouin is offline   Reply With Quote
Old 2015-07-13, 06:06 PM   #108
Piece Maker
Unicyclist
 
Piece Maker's Avatar
 
Join Date: Jun 2013
Location: Manchester, UK
Posts: 1,630
Quote:
Originally Posted by tholub View Post
Corbin Dunn, another of the world's fastest unicyclists, runs at 32psi.

Bicycle Quarterly has done a bunch of research on rolling resistance and pressure for bikes, and found that in real-world conditions, the conventional wisdom that higher PSI means less rolling resistance is actually wrong. The bump absorption of the lower-pressure tire more than makes up for the energy of the additional tire deformation. That's probably even more true for unicyclists, because micro-adjustments to correct our balance because we hit a small bump are pretty expensive in this context.
Yeah, but when I tried 32psi it felt horrible! Cornering was especially bad, I had to really push myself round. With a solid-as-is-reasonable PSI (about 50 for me) I can smoothly corner. Maybe I just need to get used to the lower running pressure?

I've seen this research, and yeah it works pretty well when you're comparing something ludicrously high like 120psi to, say, 60-80. But I think as low as 30 is a bit crazy (though obviously a 2.2" wide tyre like the TA will work with lower pressures better than a 25mm road bike tyre).
__________________
“It is well known that a vital ingredient of success is not knowing that what you're attempting can't be done. A person ignorant of the possibility of failure can be a half-brick in the path of the bicycle of history.”
Piece Maker is offline   Reply With Quote
Old 2015-07-13, 07:54 PM   #109
unibokk
Unicyclist
 
Join Date: Feb 2013
Posts: 955
Quote:
Originally Posted by bouin-bouin View Post
That's correct at a certain point of very high pressure but 30 PSI is very low ! Roger who is also quite a fast rider uses much higher pressure thant this !
So ?

Roger rides with very short cranks which reduces wheel twitch. This allows him to ride on a harder tyre. I find that riding with very short cranks it's harder to make those minute corrections as I ride.

Remember that bikes have an extra wheel which makes them more stable even with the hardest tyres.

@ P.M. With regard to the TA tyre being squishy at 32 psi etc., that might depend on the weight of the rider and his equipment. Also the new lighter TA tyre might hold up better on cornering although there's no acute corners/turns on a race track.

The reality is that top riders like Sam and Corbin are riding very fast on the TA tyre.
unibokk is offline   Reply With Quote
Old 2015-07-13, 08:19 PM   #110
tholub
Totally Doable
 
tholub's Avatar
 
Join Date: Apr 2002
Location: Berkeley, CA
Age: 50
Posts: 3,672
Quote:
Originally Posted by Piece Maker View Post
Yeah, but when I tried 32psi it felt horrible! Cornering was especially bad, I had to really push myself round. With a solid-as-is-reasonable PSI (about 50 for me) I can smoothly corner. Maybe I just need to get used to the lower running pressure?

I've seen this research, and yeah it works pretty well when you're comparing something ludicrously high like 120psi to, say, 60-80. But I think as low as 30 is a bit crazy (though obviously a 2.2" wide tyre like the TA will work with lower pressures better than a 25mm road bike tyre).
Cornering depends a lot on which tire you're running; I've ridden some tires which corner better at low PSI, others which corner better when pumped up a lot. It depends on the profile.
tholub is offline   Reply With Quote
Old 2015-07-13, 08:26 PM   #111
MuniAddict
UniGeezer - Not "2" Tired
 
MuniAddict's Avatar
 
Join Date: Aug 2006
Age: 62
Posts: 14,577
Quote:
Originally Posted by redwelly View Post
Yup, I used a new TA tyre which I weighed at 1550g.
Where is this new version of the TA available? I checked UDC UK and found only what looks like the older, heavier version. Nowhere could I find where it states that it's a new, lighter version than the old one, other than that it's "a Replacement tyre as fitted to the Qu-ax 36"", and the listed weight is higher than 1550g.[/QUOTE]
__________________
Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
Be our muniprohpet for many years more.
-Dani Buron


Website
Videos
Facebook

Last edited by MuniAddict; 2015-07-13 at 08:29 PM.
MuniAddict is offline   Reply With Quote
Old 2015-07-13, 08:36 PM   #112
Piece Maker
Unicyclist
 
Piece Maker's Avatar
 
Join Date: Jun 2013
Location: Manchester, UK
Posts: 1,630
Quote:
Originally Posted by tholub View Post
Cornering depends a lot on which tire you're running; I've ridden some tires which corner better at low PSI, others which corner better when pumped up a lot. It depends on the profile.
I was talking about the TA tyre for both my posts

I'm gonna try it tomorrow. Let some air out and just see how it handles, especially at higher speeds.

Quote:
@ P.M. With regard to the TA tyre being squishy at 32 psi etc., that might depend on the weight of the rider and his equipment. Also the new lighter TA tyre might hold up better on cornering although there's no acute corners/turns on a race track.
I'm a pretty small guy (about 5'10 and skinny as a twig) and usually just ride with a super-light bag with a water bladder in it. My Qu-Ax uni isn't the lightest though.

The point about the race track having no tight corners is a good one - but at the same time, the race track presumably is a very smooth surface, negating the need for a super-soft tyre? My usual terrain is fairly rough (Not Muni, just really crap roads and rough canal towpaths), and yet I still found 32psi too low.
__________________
“It is well known that a vital ingredient of success is not knowing that what you're attempting can't be done. A person ignorant of the possibility of failure can be a half-brick in the path of the bicycle of history.”
Piece Maker is offline   Reply With Quote
Old 2015-07-13, 08:49 PM   #113
unibokk
Unicyclist
 
Join Date: Feb 2013
Posts: 955
Quote:
Originally Posted by MuniAddict View Post
Where is this new version of the TA available? I checked UDC UK and found only what looks like the older, heavier version. Nowhere could I find where it states that it's a new, lighter version than the old one, other than that it's "a Replacement tyre as fitted to the Qu-ax 36"", and the listed weight is higher than 1550g.
[/QUOTE]


Hello Terry the 1550g tyre is available on the UDC Germany site called Municycle.com

The listing are all written in English so you'll have no problem looking it up.

Correction !! That's strange, sometimes it comes up in enlish and then sometimes in german. Anyway they have the 1550g TA tyre.

Last edited by unibokk; 2015-07-13 at 08:57 PM.
unibokk is offline   Reply With Quote
Old 2015-07-13, 09:14 PM   #114
MuniAddict
UniGeezer - Not "2" Tired
 
MuniAddict's Avatar
 
Join Date: Aug 2006
Age: 62
Posts: 14,577
Quote:
Originally Posted by unibokk View Post


Hello Terry the 1550g tyre is available on the UDC Germany site called Municycle.com

The listing are all written in English so you'll have no problem looking it up.

Correction !! That's strange, sometimes it comes up in enlish and then sometimes in german. Anyway they have the 1550g TA tyre.
The only indication of weight I could find on the site is the "Shipping weight" which is 1.5kg. So if that's the actual weight of the tire, then 1500g is pretty good. But alas, the shipping cost will be too prohibitive to the US, especially with the added 19% VAT charge. Oh well, hopefully UDC US will get them soon.
__________________
Happy Birthday Terry! Every year you get cooler, younger and unicyclier!
Be our muniprohpet for many years more.
-Dani Buron


Website
Videos
Facebook

Last edited by MuniAddict; 2015-07-13 at 09:16 PM.
MuniAddict is offline   Reply With Quote
Old 2015-07-29, 12:08 PM   #115
redwelly
Sam Wakeling
 
redwelly's Avatar
 
Join Date: Oct 2003
Location: Sheffield, UK
Age: 33
Posts: 616
Send a message via Skype™ to redwelly
Thanks to Edd Hawkes we now have a short video of the record event for you to get a better taste of what we got up to.

https://vimeo.com/134725230
redwelly is offline   Reply With Quote
Reply

Tags
100, 2015, attempting, july, mile, record, world


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
100 Mile world record attempt on March 10th magnustudios General Unicycling Discussions 49 2012-03-14 01:24 AM
Manchester to Blackpool, UK (60 mile ride) - Sunday 8th July steve.colligan General Unicycling Discussions 2 2007-06-18 09:40 PM
Zach Warren (prospective 100 mile record holder) in Boston Klaas Bil General Unicycling Discussions 0 2005-11-16 09:46 PM
Zach Warren's 100 mile record attempt postponed Klaas Bil General Unicycling Discussions 0 2005-09-23 10:38 PM
Zach Warren's attempt at breaking the 100 mile record Klaas Bil General Unicycling Discussions 27 2005-05-21 07:23 AM


All times are GMT. The time now is 01:18 PM.


Powered by vBulletin®
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright © 2001-2016 Gilby
You Rated this Thread:
Page generated in 0.09465 seconds with 11 queries