Tell Me Why My CAAD12 3+mph Faster than Fuji Touring - Controlled Experiment
10-05-18, 08:39 AM
#27
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Brake rub.
You may spin it by hand when getting ready to go and it spins fine. But perhaps after braking the first time or two something happens and the caliper or pad does something to rub.
It doesn't take a lot of brake rub to make a big difference.
I'd honestly start there. Afterwards, if it freewheels fine in the back and front by hand.......take off the chain and see how well the cranks spin by hand. They should be able to spin some and then come to a stop, they shouldn't immediately stop.
That's all I've got.
You may spin it by hand when getting ready to go and it spins fine. But perhaps after braking the first time or two something happens and the caliper or pad does something to rub.
It doesn't take a lot of brake rub to make a big difference.
I'd honestly start there. Afterwards, if it freewheels fine in the back and front by hand.......take off the chain and see how well the cranks spin by hand. They should be able to spin some and then come to a stop, they shouldn't immediately stop.
That's all I've got.
10-05-18, 11:39 AM
#29
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10-05-18, 02:12 PM
#30
SuperGimp
That and the body position. I experience the same thing when I switch between my two bikes - one is much more "reachy" and low than the other and it's faster. I dont know about 3 mph though.
10-05-18, 03:39 PM
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f) Something else?
Had you been riding one considerably more than the other, prior to your testing?
Had you been riding one considerably more than the other, prior to your testing?
10-05-18, 05:18 PM
#33
Non omnino gravis
On flat ground, the difference in weight is insignificant.
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10-05-18, 09:12 PM
#35
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That's true, but it's insignificant to a steadily-paced 15 mile ride with no stops. Each time you bring 4kg from a stop to 20mph takes only around 160 joules of energy; less than a second's worth of pedaling effort at 200W.
Extra weight doesn't increase air drag.
It can increase hub drag, but even with a 4kg penalty, we're talking about a several-percent increase to something that's only a few watts in the first place.
It can also increase rolling resistance, but even in the worst case we're only talking about a few watts, and it can mostly be compensated by tuning tire pressure appropriately for the setup.
and maintain speed.
It can increase hub drag, but even with a 4kg penalty, we're talking about a several-percent increase to something that's only a few watts in the first place.
It can also increase rolling resistance, but even in the worst case we're only talking about a few watts, and it can mostly be compensated by tuning tire pressure appropriately for the setup.
10-05-18, 09:14 PM
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It's not
I got about a 3 mph difference between my road bike and mtn bike with big fat knobby tires.
I got about a 3 mph difference between my road bike and mtn bike with big fat knobby tires.
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10-05-18, 09:31 PM
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Took a ride on an older wheelset, and the brake was rubbing. I could hear it. I was going so slow! Then I looked at my Garmin and my power was way down. I heard the brake rub, knew I wouldn't be fast, and became demotivated without really realizing it.
10-05-18, 11:13 PM
#39
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Just to be sure
The Fuji is a touring bike with 25mm tires. Geo is here https://archive.fujibikes.com/2009/Fuji/touring3
10-06-18, 02:26 AM
#40
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If your route is mostly flat and doesn't have a lot of stoplights/stop signs, then the main difference is aerodynamics. If it's hilly or if you have to stop a lot, then it's weight, especially wheel weight. Other things also play a role too (frame stiffness, for example), but these are minor compared to aerodynamics and weight.
10-06-18, 03:33 AM
#41
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If you're putting forth the same level of effort, on a heavier bike you're gonna go slower. I really don't think it's so much more complicated than that.
10-07-18, 04:41 AM
#42
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10-07-18, 04:44 AM
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That bit of nonsense .... is the premise of the thread.
I say it is 100 percent the cranks ....
like myself .... who are making this thread sparkle.
10-08-18, 11:21 AM
#45
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So I've done this controlled experiment for the last 2 weeks and found I can ride my CAAD at 20.5 mph and the Fuji at 17.1 mph averaged over 7 rides each.
Variables Controlled For:
a) Same Flat 15 mile Route (In/Out MUP with No Traffic Lights or Stops)
b) Time of Day (I alternated the days for each bike)
c) Shoes (SPD and same shoe)
d) Same Tires (both using 25mm)
Here are the key differences beteen the bikes. Which ones do you think are the main reason(s) for the speed difference?
a) BB and Cranks- (CAAD is PF 2 piece. Fuji is 3 piece ST).
b) Geometry (CAAD Stack/Reach 563/393, Fuji 588/383)
c) Frame material and/or stiffness (CAAD is Alu, Fuji Steel)
d) Weight (CAAD is 18 pounds, Fuji 26 pounds)
e) Wheelset (CAAD is sealed bearing 1600g, Fuji is touring wheels with loose balls and 2200g)
f) Something else?
Variables Controlled For:
a) Same Flat 15 mile Route (In/Out MUP with No Traffic Lights or Stops)
b) Time of Day (I alternated the days for each bike)
c) Shoes (SPD and same shoe)
d) Same Tires (both using 25mm)
Here are the key differences beteen the bikes. Which ones do you think are the main reason(s) for the speed difference?
a) BB and Cranks- (CAAD is PF 2 piece. Fuji is 3 piece ST).
b) Geometry (CAAD Stack/Reach 563/393, Fuji 588/383)
c) Frame material and/or stiffness (CAAD is Alu, Fuji Steel)
d) Weight (CAAD is 18 pounds, Fuji 26 pounds)
e) Wheelset (CAAD is sealed bearing 1600g, Fuji is touring wheels with loose balls and 2200g)
f) Something else?
10-08-18, 12:25 PM
#46
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What is your gearing? I could see a difference if you have something like a 52 big ring vs 53, or 50 vs 53. You could be in the sweet spot on the CAAD.
Ha same here, 80 PSI on 25mm vs 40psi on 2.2" is about 3mph slower.
10-08-18, 12:49 PM
#47
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The weight isn't going to make that much difference, even if it wasn't flat. Aerodynamics could, but that's obvious so assuming that your back angle (primary factor) is more or less the same on both bikes ...
... you didn't answer my question so there is some speculation but if you are accustomed to riding one of them - multiples of the time spent on the other - then you are going to be naturally faster on it. Everything from crank length, handling differences, to cadence during accelerations will be factors due to training specificity.
... you didn't answer my question so there is some speculation but if you are accustomed to riding one of them - multiples of the time spent on the other - then you are going to be naturally faster on it. Everything from crank length, handling differences, to cadence during accelerations will be factors due to training specificity.
10-08-18, 09:21 PM
#48
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I'm going to go out on a limb and say the Fujis bike computer is computing for 26" wheels. That would account for almost 2mph. The rest could reasonobly be accounted for by all of the other factors above...position/aero/effort.
10-08-18, 09:32 PM
#49
Non omnino gravis
I cannot directly compare the average speed of my CX bike on 700x35s and my road bike on 700x25s, because I seldom take my road bike on shortcuts through dirt fields or out into the riverbed. By seldom, I mean never.
To make a weak analogy, just because a rake makes a terrible shovel doesn't mean it's a bad rake.
To make a weak analogy, just because a rake makes a terrible shovel doesn't mean it's a bad rake.
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