JOSEPHWEISSERT
Zen MBB Master
I was using 28 mm (26.5 mm actual) Continental Gatorskin tires on my Vendetta with heavy butyl tubes made for 28 mm tires. Today, I replaced them with 25 mm (25 mm actual) Continental Grand Prix 4000 S II tires and some Conti tubes made for 25 mm tires. I weighed all of the tubes and tires and I shaved off about 1/3 of a pound of rotational mass. So that should make some difference when sprinting, because I'll be able to rotate the tires up to speed faster than before. It also means less weight to haul up a hill, although that's probably not going to be noticeable. But the big difference (and the main reason to change) is to reduce rolling resistance. If I understand the data correctly, I should be able to gain a 20 watt advantage with these new tires alone compared to the old tires. That's significant power for free.
So I just had to go out and test these new tires instead of waiting for a shop ride. I did an out and back route (go east, go north, turn around, go back south, go back west) to balance out any wind - although it wasn't very windy. There were some rollers and some flats. I went for an hour and five minutes. Keep in mind that I just did a hard 104 miles yesterday, so I wanted to keep it somewhat light. My average HR ended up being 132 bpm. That's not too bad since my recovery rate is 120 or less, and my aerobic base is around 141. So I didn't push it too hard, but I didn't go really easy either. I also had to adjust my numbers when I got home because I forgot to set my cyclo-computer wheel size before riding. So I got home, did a rollout test, reset my computer settings for wheel size, and recalculated my data.
Here's all I can say about the new tires: Holy Crap Batman!!! I felt the difference as soon as I took off in the driveway. Then I could still feel it on the road. I felt it all the way out and all the way back. The old tires felt like glue compared with these new tires. So I was able to do an average of 21.36 mph for a little over an hour with an average heart rate of 132. I know this is all subjective, because I have no way to compare it scientifically. But wow! I could feel the difference right away. I really need to start looking at some lighter, more aerodynamic wheels too.
So I just had to go out and test these new tires instead of waiting for a shop ride. I did an out and back route (go east, go north, turn around, go back south, go back west) to balance out any wind - although it wasn't very windy. There were some rollers and some flats. I went for an hour and five minutes. Keep in mind that I just did a hard 104 miles yesterday, so I wanted to keep it somewhat light. My average HR ended up being 132 bpm. That's not too bad since my recovery rate is 120 or less, and my aerobic base is around 141. So I didn't push it too hard, but I didn't go really easy either. I also had to adjust my numbers when I got home because I forgot to set my cyclo-computer wheel size before riding. So I got home, did a rollout test, reset my computer settings for wheel size, and recalculated my data.
Here's all I can say about the new tires: Holy Crap Batman!!! I felt the difference as soon as I took off in the driveway. Then I could still feel it on the road. I felt it all the way out and all the way back. The old tires felt like glue compared with these new tires. So I was able to do an average of 21.36 mph for a little over an hour with an average heart rate of 132. I know this is all subjective, because I have no way to compare it scientifically. But wow! I could feel the difference right away. I really need to start looking at some lighter, more aerodynamic wheels too.
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