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New pump costing me 200m a day
Just got a shiny (literally) new Lezyne floor pump. Best piece of kit I have ever bought (sorry bike.) The screw on chuck means no air escapes no matter how hard you pump. I am embarrassed to say the hard tires I had before might have been as little as 45-50psi with my old hand pump. They are now a diamond like 115psi. Too many punctures on the way to work was worth £45, cheaper than the sack. But I have discovered it has cost me another way. My 18.8km round trip to work now only takes me 18.6km (?!) My tires are so well inflated that the diameter is greater and it takes less rotations to get in and out. This could cost me hundreds of kilometers by the end of the year and some long hours in the saddle rounding up to the nearest thousand kiliometers. Swings/Roundabouts.
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- SamSeed 12 sec ago
My 6KU, replaced everything but the front chainring over the past 5 years.
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This was a very good listing of bikes for under 1,000....
- Hirsute 5 hours 18 min ago
Radar tells me their closing speed, if they are slowing and how far away. Then I decide to say a prayer. The change of light pattern is incidental.
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Quite so, which is why our village 20mph zone covers the whole residential extent. Of course, enforcement is another thing..
- lonpfrb 6 hours 4 min ago
No, that's very doubtful while proper testing would be fully destructive.
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What's wrong with dropping down on to the Millenium Bridge, or the swing bridge, then the brief, but satisfying climb back up the hill? #training....
- chrisonabike 7 hours 59 min ago
The relatives might of course disagree, but in general I'd countenance a relatively light sentence* if only we could fix it so that those who...
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Id forgotten that I got a second hand set of project two's for my getting to work bike over twenty years back.
- Veganpotter 9 hours 35 min ago
My bet is that all these tires popping off are from people with bad pressure gauges or they're simply just putting too much air in on purpose. ...
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10 comments
sarcasm doesn't always come across that easily online, does it?
track pumps rule
Oh - and I forgot to say: I bought a Lezyne floor pump last year (the steel CNCed one) and it is brilliant - an absolute corker.
Quite possible. If you have a magnet type odometer, you calibrate it by rolling the bike along the ground. If the tyres are flat when you calibrate, you get a shorter distance for each turn of the wheel. So you now ride to work and get 18.8kms.
If you now inflate the tyres and do not recalibrate the odometer, you will now have a larger diameter wheel (the tyre gets 'puffed out'). This will now take fewer revolutions and you will get a shorter distance - say 18.6kms - since the odometer will register fewer clicks of the magnet.
200m is under 1%, so can be explained by an additional 2.5-3mm increase in wheel radius (5-6mm diameter) due to pumping your tyres up.
If you are using a GPS unit, then some sort of space-time continuum warping due to increased speed is a more plausible reason.
Bingo JMac, I thought the diameter comment was clear, you know as radius, diameter, circumference are all really the same thing, wibbly wobbly circly pi.
I don't think I will remeasure as that might be considered cheating, but I will cut and paste my commute figure and take the bike computer figure for new rides. My tracking isn't GPS, more Excel. Fact: GPS satellites do travel at relativistic velocities and their locations are calculates using general relativity, Newtonian physics would drift out by metres and break the system in a few days.
great stuff:
http://www.wiggle.co.uk/lezyne-classic-floor-drive-abs-track-pump/
The world isn't shrinking, it is expanding according to Neal Adams:
http://www.youtube.com/watch?v=oJfBSc6e7QQ
He is absolutely crackers of course, his comments are even more entertaining than the video.
I think you will find that the earth is shrinking, so nothing to worry about
I could be completely wrong but theoretically, if your tires are marginally bigger wouldn't your wheel factor/circumference approximation change? So if your wheel diameter is now slightly bigger but you're using the same wheel factor calculation on your cyclometer then since the number of revolutions is decreased due to a larger wheel traveling the same distance you would get a "shorter" distance traveled because the computer doesn't know that your wheel diameter has changed? I think the last few sentences would make more sense with a glass of wine.
I don't know how the distance has changed.
The distance was x between point a and b..you cannot change that.
Your wheels may take less rotations to cover the distance, but the distance simply cannot change. No matter what you do, if you are taking exactly the same route, day in day out.
I think he means distance on bike computer as opposed to real distance.