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Advice on tire pressure from Garmin mechanic

Posted: Tue Nov 16, 2010 2:41 pm
by Lister Farrar
http://velonews.competitor.com/2010/11/ ... ent_149851

More is less.

Other good advice on equipment choice, ADDING weight to bikes, and what should matter to amateur racers on equipment choice.

Nice to know a protour mechanic says clinchers offer lower rolling resistance than tubulars. Woo-hoo, we're all on the right track! (I think; does anyone use tubulars?)

Re: Advice on tire pressure from Garmin mechanic

Posted: Tue Nov 16, 2010 3:44 pm
by Quentin
Ask Nick is the best column on VeloNews.

Re: Advice on tire pressure from Garmin mechanic

Posted: Tue Nov 16, 2010 4:13 pm
by AdamD
Bruce is on tubs

Re: Advice on tire pressure from Garmin mechanic

Posted: Wed Nov 17, 2010 6:20 pm
by steven grandy
Tubbies vs clinchers.
I've seen rolling resistance data that puts them as equivalent. The clinchers need latex tubes to close the gap with good latex tubulars.

Re: Advice on tire pressure from Garmin mechanic

Posted: Wed Nov 17, 2010 9:20 pm
by Brian S
OH Yeah? Well my tubulars can beat your clinchers any day. I think the weight savings is a very big deal and of course the overall quality of the wheel set. Now, if we could all afford full carbon rim clinchers......

http://triathlon.competitor.com/2010/11 ... hers_16420

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 10:24 am
by Lister Farrar
(Warning: retrogrouch rant)

The numbers show rolling resistance, weight and aerodynamic advantages of specialty wheels are much less clear*, from those who measure such things.

*Unless of course you believe they are an advantage, in which case they do work. :)

Rolling resistance tests

"A rider asked how much time it was worth to ride clinchers in a 3k pursuit. Our analysis said it would be about a 2.5 second advantage to ride clinchers over tubulars glued with road glue."
http://www.analyticcycling.com/ForcesTires_Page.html

8 watts more work to push the best tubular, over the best clincher, according to this study.
clinchers: http://ddata.over-blog.com/xxxyyy/0/02/ ... specs.html
tubulars: http://ddata.over-blog.com/xxxyyy/0/02/ ... specs.html

(One potential fault with these studies is the smooth roller used. I guess they have to do that to get reproduceable results, but tire flex over road texture is also a factor.)

Weight effect (wheels, not just tires):
Sprinting
500 grams lighter wheels, gain you 1.88 m in a 250 metre sprint. Enough to win a sprint instead of second I suppose, but peanuts compared to training, tactics and skill.
http://en.wikipedia.org/wiki/Bicycle_performance

Climbing
"The formula for power suggests that 500g saved is worth 0.06 mph (0.1 km/h) on a 7% grade"
Or about 100 metres in a one hour climb. Or 1.6 metres on a 1 minute climb like King George terrace. And 500g is a lot. 32 spoke conventional wheels (ultegra hubs on open pro rims)are 1682 g, compared to, for eg, zipp 303 at 1100 grams.

According to this study, the total effect of the lightest possible wheels (Lew) over the heaviest measured wheels (mavic aksium), to accelerate from 0 to 30 kph, over 10 seconds? 7 watts. Less than the diffeence between the best tubular and the best clincher.
http://www.rouesartisanales.com/article-15988284.html

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 12:44 pm
by Josh.E
You can only lose energy to wind and rolling resistance. All calculations of energy required to accelerate in a given time need to factor in the extra kinetic energy you then have due to having more moving mass. You do more work climbing a hill, you do less work desending a hill.

Mone of this is even in the same universe of magnitude as the amount of bimechanical energy you waste pushing and pulling on the bike in directions that do no useful work (work that translates to forward motion)

Fancy bikes don't make you faster.
Shawn had a brick strapped on to the rack of his commuter bike for wednesday hills......

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 12:56 pm
by Brian S
Josh.E wrote:Fancy bikes don't make you faster.....
Oh Lister, it is so much fun to get you going. I fully agree Josh, and have always loved the cheapest way to get a new fancy lighter bike that goes uphill so much easier.......10 lbs off one's own frame.

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 1:02 pm
by Josh.E
That methods working for Gavin Pantani, formerly known as Moose, who was pulling his now deer-like 193lb body up the hills right at the very front of the group this wednesday.

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 1:31 pm
by Lister Farrar
Josh.E wrote:That methods working for Gavin Pantani, formerly known as Moose, who was pulling his now deer-like 193lb body up the hills right at the very front of the group this wednesday.
I was thinking more like RasMOOSEn.

Go Chicken!

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 1:41 pm
by Lister Farrar
Brian S wrote:Oh Lister, it is so much fun to get you going.
guilty. Where's the emoticon for 'fished in'? :oops:

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 1:42 pm
by Josh.E
rasMOOSEn :lol:
that's a good one

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 1:55 pm
by Rolf
Josh.E wrote: Shawn had a brick strapped on to the rack of his commuter bike for wednesday hills......
Hey Shawn: the Bianchi's available for "elite training" most days. Just ask. I've even got a Kryptonite lock I can put on for ya.

I'd be proud to continue to support the development of TripleShot Spinnakers Racing... by skipping Wednesday hills. :roll:

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 5:02 pm
by shawnc
I'd be proud to continue to support the development of TripleShot Spinnakers Racing... by skipping Wednesday hills.
Rolf, I've never seen such a courageous and selfless act. You inspire me to be a better person.

I think next week I will have two bricks. I'll also need a barf bucket if I have to keep up with Josh, John T, and the Cyclist Formerly Known As Moose again :mrgreen:

Re: Advice on tire pressure from Garmin mechanic

Posted: Thu Nov 18, 2010 7:43 pm
by JohnT
Spendng money on fancy equipment will make you faster. Not faster than guys who train with bricks or do extra Sinclair's just for the fun of it, but faster nonetheless. Thinking of pressure, has anyone ever calibrated their pump?

Re: Advice on tire pressure from Garmin mechanic

Posted: Fri Nov 19, 2010 8:49 am
by Lister Farrar
JohnT wrote:Spendng money on fancy equipment will make you faster. Not faster than guys who train with bricks or do extra Sinclair's just for the fun of it, but faster nonetheless. Thinking of pressure, has anyone ever calibrated their pump?
Good point. I imagine the gauges are subject to all kinds of abuse and error. I suppose just checking the pressure after pumping with another gauge would do it?