Penn State's mentor group - CLOSED! (Page 30)

WittyCityGirl - 2010-04-26 12:25 PM How do we make it a requirement that all races end with a slip in slide?!

phxphotog - 2010-04-26 6:23 PM Could you guys look at my data from my Garmin from the bike and run for last weekends Olympic? My HR seems high for the 15 weeks I trained. Here's the data:

furiousferret - 2010-04-26 10:38 PM phxphotog,

I don't think your HR is that bad, its a little high but its an olympic distance and it should be a tad high.  Also, everyones' HR is different and its hard to judge each individual unless you are looking at their logs for a few weeks.

PennState - 2010-04-27 6:00 AM Yes, everyone's HR is different. There are many variables that affect even within the individual. For me, 160 bpm is a very string run effort, for another person it is Z1 and easy as pie. HR training can be fun, but its also easily misunderstood.

furiousferret - 2010-04-26 8:41 PM Penn State,

Here is the elevation profile for the bike of IMSG, I think it adds up to about 6500 of gain:

Kath2163 - 2010-04-27 9:47 AM

It depends on what pressure you're running the tires at.  But in general, I'd say yes, smaller tires will have a smaller contact patch with the ground and therefore less traction.  Often, a smaller tire will be run at a higher PSI. 

This of it like this, if someone weighs 100lbs and was supported by only one tire at 100psi (pounds per square inch), then that one tire would deform under it to make one square inch of it be in contact with the ground to hold that persons 100lbs of weight.  Now if you made that tire 120psi, that tire would not need as much surface area to hold that weight.  It would now only need a 0.83 square inch in contact with the ground to hold that 100lbs.  Less rubber on the ground = less traction.  It also = less rolling resistance, but ONLY on a perfectly smooth road.  Once you get on a surface that's not perfectly smooth which is probably most streets we all ride on (not many get a freshly paved pure blacktop road to ride on), that extra pressure actually begins to make that tire bounce slightly, which takes away traction.  I'm not saying bounce like an inch off the ground, but very small amounts... it adds up and takes away traction.  That is why if you read information on it you'll find that running a really high psi is actually NOT faster than running a moderate one.  Too much traction slows you down with friction, too little traction doesn't transfer your power to the pavement and slows you down.

We use two tires obviously, in an equally distributed weight situation with 2 tires at 100psi, you'd have 0.5 square inches in contact with the ground on each tire, but technically we put something more weight on our rear tire than our front (at least cyclists do on road bikes, not sure about triathletes in aero on a tri bike), I think it's around 60/40 split in weight distribution? (someone correct me if I'm wrong).  So I actually run a slightly higher PSI on the rear tire compared to the front tire.  I weight ~155lbs, I run 95-100psi on the front and 105-110psi in the rear on 700x23s.  I actually used to run some 700x19s at 120-130psi, but found once I moved to the 23s it was a more comfortable ride and just as fast.  The difference in speed was probably unmeasurable for me if there was a change in speed, but the comfort level was noticeable.