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  1. #1
    Home School Valedictorian 02Giant's Avatar
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    Considerably Slower on Today's Ride

    There is a 17 mile ea. way point A to point B then back to A, MUP route I ride fairly often. Today I was a good four minutes slower each way. There were two changes, first I lowered my air pressure, following the 45/55% based on my and the bikes combined weight. I was 80 psi. front vs. my usual 120, and 99 rear vs. my usual 120. The ride was definitely smoother, and didn't feel slower. The second change, I concentrated on spinning vs. mashing the gears. My knees felt much better, my heart rate was about 15 bpm average lower than usual.

    Was the lower psi. more rolling resistance, the spinning a psychological thing, my legs were going faster, so I assumed I was going faster, maybe both?
    We've got no fear, no doubt, all in balls out

  2. #2
    Senior Member Northwestrider's Avatar
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    I haven't noticed much speed difference during a fairly small change of tire pressure. YMMV. If your not used to spinning, it may take awhile to get used to it and back to your normal times

  3. #3
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    Quote Originally Posted by 02Giant View Post
    There is a 17 mile ea. way point A to point B then back to A, MUP route I ride fairly often. Today I was a good four minutes slower each way. There were two changes, first I lowered my air pressure, following the 45/55% based on my and the bikes combined weight. I was 80 psi. front vs. my usual 120, and 99 rear vs. my usual 120. The ride was definitely smoother, and didn't feel slower. The second change, I concentrated on spinning vs. mashing the gears. My knees felt much better, my heart rate was about 15 bpm average lower than usual.

    Was the lower psi. more rolling resistance, the spinning a psychological thing, my legs were going faster, so I assumed I was going faster, maybe both?
    They key to answering questions such as yours is changing just one thing at a time. I'd go back out there with the higher pressures back in the tyres, and spin your way around your route again. Check the times.

    I think spinning is probably a better thing, especially as you allude to it improving the feel of your knees. So I would keep riding with the higher cadence for a week or so, take a time, then lower the tyre pressures. I wouldn't go so low as you did today; I also don't differentiate between front and rear. However, you don't say what size (width) your tyres are. If 23C, I would probably opt for 90 front and rear.

    FWIW, spinning is probably the reason why you took more time to do your ride. It's a learned action, and over time, you will be able to shift to harder gears while maintaining the same cadence, and will therefore ride faster.
    Dream. Dare. Do.

  4. #4
    Home School Valedictorian 02Giant's Avatar
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    Tires are 23c.
    We've got no fear, no doubt, all in balls out

  5. #5
    rugged individualist wphamilton's Avatar
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    Quote Originally Posted by 02Giant View Post
    There is a 17 mile ea. way point A to point B then back to A, MUP route I ride fairly often. Today I was a good four minutes slower each way. There were two changes, first I lowered my air pressure, following the 45/55% based on my and the bikes combined weight. I was 80 psi. front vs. my usual 120, and 99 rear vs. my usual 120. The ride was definitely smoother, and didn't feel slower. The second change, I concentrated on spinning vs. mashing the gears. My knees felt much better, my heart rate was about 15 bpm average lower than usual.

    Was the lower psi. more rolling resistance, the spinning a psychological thing, my legs were going faster, so I assumed I was going faster, maybe both?
    My guess is that it had to do with the bold-faced part. You expect spinning at a higher cadence to increase the heart rate, but your's was lower. I would investigate the theory that, unused to the higher cadence, your effort level was lower than your normal performance.

  6. #6
    rebmeM roineS JanMM's Avatar
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    If you make more than one change in a process, you can't say with assurance which change caused the results to be different.
    (I would guess spinning, too.)
    RANS V3 (steel), RANS V-Rex, RANS Screamer

  7. #7
    Senior Member Retro Grouch's Avatar
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    Quote Originally Posted by wphamilton View Post
    My guess is that it had to do with the bold-faced part. You expect spinning at a higher cadence to increase the heart rate, but your's was lower. I would investigate the theory that, unused to the higher cadence, your effort level was lower than your normal performance.
    That's what I was thinking too. Working less hard usually results in slower times.
    My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.

  8. #8
    Home School Valedictorian 02Giant's Avatar
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    Thanks for the replies!

    i think I will go back to the pressures I had been running and see what comes of it, and keep working on the spinning.
    We've got no fear, no doubt, all in balls out

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    Quote Originally Posted by 02Giant View Post
    The ride was definitely smoother, and didn't feel slower. The second change, I concentrated on spinning vs. mashing the gears. My knees felt much better, my heart rate was about 15 bpm average lower than usual.

    Was the lower psi. more rolling resistance, the spinning a psychological thing, my legs were going faster, so I assumed I was going faster, maybe both?
    You were definitely putting out less power, hence the lower HR. The lower PSI may have made a marginal difference but the lower power was the primary culprit.

    Do you have cycle computer that shows speed?

  10. #10
    Home School Valedictorian 02Giant's Avatar
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    I have been using the Strava app on my phone, my eye sight is so bad up close, I can't see it while I am riding, I have to wait until I get done and put on my glasses to see it.
    We've got no fear, no doubt, all in balls out

  11. #11
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    if you want to have a clear indication of performance changes, it's best to change one thing at a time...

  12. #12
    don't try this at home. rm -rf's Avatar
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    Quote Originally Posted by 02Giant View Post
    I have been using the Strava app on my phone, my eye sight is so bad up close, I can't see it while I am riding, I have to wait until I get done and put on my glasses to see it.
    Do you need reading glasses? Stick-on bifocals work great. See this previous thread post. But it still might be hard to see the phone in bright sunlight.


    At 170 lbs, I used 90-95 psi front / 105-110 psi rear on 23c GP4000S tires. Under 90 psi made the bike feel a little mushy, instead of the quick steering with higher pressures. (Now I'm riding 25c at 85/100-105)
    Last edited by rm -rf; 05-18-14 at 09:02 PM.

  13. #13
    Home School Valedictorian 02Giant's Avatar
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    Quote Originally Posted by rm -rf View Post
    Do you need reading glasses? Stick-on bifocals work great. See this previous thread post. But it still might be hard to see the phone in bright sunlight.


    At 170 lbs, I used 90-95 psi front / 105-110 psi rear on 23c GP4000S tires. Under 90 psi made the bike feel a little mushy, instead of the quick steering with higher pressures. (Now I'm riding 25c at 85/100-105)
    I need and use them, they don't work out while I am on the bike. Checking the link you provided, I will be looking into the stick on today. I wear sun glasses while riding and those may be just what I need. Thanks!

    I too am on GP4000S 23c tires. My combined weight with the bike is 180#, so the 45/55 split was basically 80/100, I will likely go 90/105, see what it feels like.

    On my route, 17 mi. each way, my first ride this year was 58 min., after my fifth I was down to just over 50 min. and looking for sub 50 when I made the changes and jumped back to 54 min. I think I need to ignore the time somewhat and concentrate on improving the higher cadence.
    We've got no fear, no doubt, all in balls out

  14. #14
    Home School Valedictorian 02Giant's Avatar
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    Quote Originally Posted by rm -rf View Post
    Do you need reading glasses? Stick-on bifocals work great. See this previous thread post. But it still might be hard to see the phone in bright sunlight.


    At 170 lbs, I used 90-95 psi front / 105-110 psi rear on 23c GP4000S tires. Under 90 psi made the bike feel a little mushy, instead of the quick steering with higher pressures. (Now I'm riding 25c at 85/100-105)
    Just wanted to say Thanks! again. I ordered a pair within a day or two of your reply, received last Thursday and attached them to my cycling glasses. I used them Saturday, they were great! I was finally able to see the screen.
    We've got no fear, no doubt, all in balls out

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    Senior Member skol's Avatar
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    hard to have identical wind conditions each day, motivation, time of day, what you ate etc..but agree probably the increased cadence was the difference. I think its good to experiment but at the end of the day its never fast enough...

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