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There are several places here on RoadRageCycling that I have discussed tire pressure from a variety of angles and today I submit another supporting article gleaned from tech data at yesterday's 2013 running of the legendary Paris-Roubaix.
Now, first; I should say that most of us do not ride under the conditions seen on any running of this historically punishing race. The distance, conditions, road surfaces, and intensity are factors that the sane among us usually try to avoid. Coupled with certain equipment choices that are not available or accessible to many of us - I will admit that a grain or two of salt should be used as you analyze this data and begin to apply it to your cycling preparation and habits.
However; the data also supports some techniques that I have been trumpeting for some time now as I have been using them in my cycling life and found the results to be favorable.
Release some pressure
First among these concepts is less tire pressure. I have written before about how many of us over-inflate our tires. Inflating past the manufacturer's recommended pressure asks for trouble on several fronts: not just catastrophic failure of the tire - but potentially the rim as many clincher rims actually have relatively low pressure thresholds (often below 120-130 psi).
Secondly though a softer tire is proving to be favorable. Lower pressure is not only more comfortable as it allows the tire to work more effectively as a form of suspension but also enables the tire to conform to the imperfections of the road. This additional propensity to conform to the road provides greater adhesion in corners and reduces the minuscule vertical undulations of the tire->wheel->bicycle resulting in wasted energy. (I.e.: lower pressure results in more forward movement for less energy expended). I think we can all agree than more traction and more efficiency are good things.
I don't recall if I have written directly on this topic on the blog or not (perhaps I should show some initiative and pour through my archives...maybe later); but I have long been an advotate of using different pressure for your front and rear tires. This is exceptionally common at the elite levels and in other industries as well. When you think about it - there is a lot of logic behind the practice: front and rear tires do different jobs and different loads to bear and the pressure ought to vary accordingly.
Depending on conditions, my front tire will be anywhere from 5-10 psi lower than the front in overall pressure. Because the front 1) does all the steering and requires more traction 2) supports less weight and therefore is under less of a load and 3) is the first part of the bike to encounter a bump or rough surfaces therefore works as the bicycle`s primary suspension reduced pressure relative to the rear tire allows it to perform those tasks better than at a higher relative pressure.
Things to Note:
These pressures are exceptionally low and it is for several reasons: 1) these teams are using tubular tires which safely allow for lower pressures 2) let`s be honest; a lot of these guys are smaller than us... :) (I`m roughly the same stature as BIG Thor Hushovd at 6`0 and180 lbs racing weight and he is considered a big cyclist) and 3) these tire widths are wider than what many of us are using. I have been a fan of moving to 25 mm tires for everyday use but most of us are still running around on 23`s out of habit`s sake. This chart`s sample of teams has most tires landing between 27 and 30 mm with one team running the narrowest in the race: 25mm. Wider tires with higher air volume allow for lower pressures and similar safety and efficiency with increased lateral adhesion and vibration damping.
That said; here is the data:
Team Sky: Precise numbers are secret, “every tire is under 5.5bar (80 psi)”
FDJ: 70 front, 80 rear
63 front, 75 rear
RadioShack-Leopard: Cancellara used 5.6bar (81psi) front and 6.1bar (88bar) rear
Omega Pharma-Quick Step: Terpstra had less than 60psi front and under 65 rear
Katusha: Less than 6 bar (87psi)
Endura NetApp: 81psi front, 87 rear
Bretagne-Seche Environnement: 75 front, 82 rear
“less than 6 bar (87psi)”
Argos-Shimano: John Degenkolb ran 5 bar (72psi) front and 5.3 bar (76psi) rear
Orica-GreenEdge: 72 to 87psi, depending on rider
BMC: Under 6bar (87psi)
Lampre-Merida: around 6bar (87psi)
Blanco: Under 72psi front, under 80psi rear
Cofidis: 70-80 psi, depending in rider
Garmin-Sharp: 5-6 bar (72-87psi)
Source: VeloNewsPro cyclists are a practical bunch. If it is going to cost them races; they're not going to do it. So perhaps we can learn a thing or two from yesterday's tire pressures.
Here's my typical set up for the tires I am currently using:
Continental 4000s 23mm: Front: 90-100 psi, Rear: 100-110 psi (Max 120)
Continental 4000s 25mm: Front: 85-95 psi, Rear: 90-100 psi (Max 120)
Michelin Krylion Carbon 23mm: Front: 90-100 psi, Rear: 100-110 psi (Max 116)
Ritchey SpeedMax Cross Pro 32mm: Front: 60-70 psi, Rear: 65-80 psi (Max 85)
Continental 4000s 23mm: Front: 80-95 psi, Rear: 90-100 psi (Max 120)
Continental 4000s 25mm: Front: 75-90 psi, Rear: 85-100 psi (Max 120)
Michelin Krylion Carbon 23mm: Front: 85-95 psi, Rear: 90-100 psi (Max 116)
Ritchey SpeedMax Cross Pro 32mm: Front: 45-65 psi, Rear: 55-70 psi (Max 85)
What are your thoughts? Is there anything in the numbers above that sticks out to you? Do you plan on making any changes or not? Why?
Above all else - some of the best riding of the year is around the corner. Get out there and enjoy it!