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• #44802
I'm 187cm and (with bike and kit) around 88kg.
My girlfriend is 167cm and with bike and kit (heavy bike) around 65kg, she is very slim.
When out riding on Sunday she had to chase me down hills when I was on the hoods freewheeling.
Is my ~30kg "advantage" that dramatic, or do I have particularly aerodynamic knees?
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• #44803
Smoother bearings and better rolling tyres?
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• #44804
you're just fat.
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• #44805
heavier = faster downhill.
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• #44806
Position on the bike might be more aero, and your bike might have less drag too (tyres, spokes, bearings etc). But weight is going to be a biggie.
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• #44807
I was sitting pretty upright- on the hoods, she was in a tuck chasing me.
Reason I ask is I had thought that my being so upright would act as a brake, counteracting my huge fatness.
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• #44808
I could be wrong but weight make a bigger difference than aerodynamic when descending.
I'm sure mdcc_tester will come along and correct me like a rude 5 years old who use the wrong crayon to paint Superman with.
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• #44809
Depends what your bikefit is like, some people even when on the hoods are not that upright.
We are also assuming she never slowed down at some point and lost momentum.
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• #44810
How long should I except a GXP BB to last?
Mines making awful noises unless I take it apart after every few rides, its probably done ~2.5km
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• #44811
How short are your rides if a few of them is still under 2.5km?
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• #44812
Is my ~30kg "advantage" that dramatic, or do I have particularly aerodynamic knees?
If in doubt, do the maths.
Let's say, for the sake or argument, you're riding side by side at 15m/s (about 33.5mph) down a 1:10 slope. You're dropping at 1.5m/s, and the gravitational pull on your 30kg spare tyre is about 294N. Power equals force times speed, so the earth's pull is giving you 294×1.5=441W for free compared with your gf. Roughly speaking, at that speed she has already reached terminal velocity but you have ~300W (441W less the extra that you are using to be doing 15m/s, given your greater frontal area) of extra gravity power still accelerating you. Since she is lighter, she probably only needs about 200W from the pedals to keep accelerating alongside you at that point, while you keep freewheeling up to your terminal velocity of around 18m/s
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• #44813
duh
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• #44814
How short are your rides if a few of them is still under 2.5km?
unless he means 2.5k miles ... ?
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• #44815
terminal velocity
reported for death threats.
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• #44816
If in doubt, do the maths.
Let's say, for the sake or argument, you're riding side by side at 15m/s (about 33.5mph) down a 1:10 slope. You're dropping at 1.5m/s, and the gravitational pull on your 30kg spare tyre is about 294N. Power equals force times speed, so the earth's pull is giving you 294×1.5=441W for free compared with your gf. Roughly speaking, at that speed she has already reached terminal velocity but you have ~300W (441W less the extra that you are using to be doing 15m/s, given your greater frontal area) of extra gravity power still accelerating you. Since she is lighter, she probably only needs about 200W from the pedals to keep accelerating alongside you at that point, while you keep freewheeling up to your terminal velocity of around 18m/s
So what you are saying is that it is Power Fat?
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• #44817
Idle muscle would be more useful.
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• #44818
You have to work with what you have.
Feel the force of my PowerFat!
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• #44819
Otherwise known as the Hippycep
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• #44820
It's a little know fact that the largest challenge he faced in his 24 was finding a 500 mile downhill.
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• #44821
I'm 187cm and (with bike and kit) around 88kg.
My girlfriend is 167cm and with bike and kit (heavy bike) around 65kg, she is very slim.
When out riding on Sunday she had to chase me down hills when I was on the hoods freewheeling.
Is my ~30kg "advantage" that dramatic, or do I have particularly aerodynamic knees?
You are more magnetic therefore your magnetic field interacts more strongly with the earth's magnetic field, so you are faster.
Unfortunately, no one is quite sure how magnets work. This is currently being studied by Detroit's finest minds.
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• #44822
I knew wrapping my legs with copper wire was a good idea.
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• #44823
The red wings?
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• #44824
Tester can you give us similar numbers for dammit and his girlfriend's energy expenditure going up the same hill at between 10-15 mph?
Out of interest there is close to 60kg weight diff between me and my girlfriend and the bikes we will be riding around the iow next week :-/
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• #44825
What are the main differences between the lezyne macro and mini? My moon mask has just died on me and i've sent it back to wiggle and i'm awaiting a response however i wanted some new lights anyhows, also, i don't want an excuse to not ride to work on these glorious mornings?
Cheers
This page has a pretty cool comparer at the bottom, just select the models in the drop down and drag the slider across
edit fwiw, I'd go for the macro because of the mount being easier to take off and swap bikes with.
http://www3.big.or.jp/~number-1/No.1_ShimanoHBRM50F.html is an html version of the EV, the very similar HB-RM40 in on techdocs.shimano.com and also on www.paul-lange.de which has a bigger archive of EV.pdf than shimano.com