Tuesday, July 23, 2013

Summer heat and rolling resistance

I've got an ongoing research project.  Perhaps it's destined to be a lifetime research project.  Let me explain.

As the days get hotter, and the pavement gets correspondingly hotter, how does it affect rolling resistance?

1) On the one hand, we've all seen water droplets "sizzle" across a hot skillet.  Do bicycle tires "sizzle" on the pavement surface in similar fashion?  Which would decrease rolling resistance, one would think.

2) Or, on the other hand, we've all seen how a cube of butter melts on a hot skillet, increasing the "contact patch" and becoming generally less wieldy.  (Surely melted butter has more "resistance" than a solid stick of butter!)

So far, my research has been based solely on personal observation.  And even after many years, the results are "inconclusive."  I will continue to observe.  Input from other "guinea pigs" would be welcomed!

(I'll be disappointed if I've spent so much time and effort, and somebody tells me "there's an app for that," available on your smart phone!)


David said...

No hard data here, but I can tell you about a long hot ride on July 4th in Florida.

I decided to ride my bike to the in-laws instead of driving with my family. (it's a 50+ mile trip, so I would drive back with them.) I got a really late start so I was riding in the heat of the day. At about 3 o'clock I was at 47 miles when a patch on the rear tube melted off from the heat. At that point my rolling resistance increased significantly.

Good luck with your study. I find that perceived rolling resistance is more affected by how I feel than the temperature.

Marcus said...

Working for bike shops (for profit and non profit) and educating folks about transportation cycling (Safe routes to School program) has compelled me to study rolling resistance and its complexities. I ride voluminous tires with as little tread I can find at lower pressures for MTB and commuting. They have proved to be great in most conditions (I use studded tires on Ice).
Great articles about tire rolling resistance:
Wind Resistance: