w****1
发帖数: 4931 | 1 Just want to have an idea how much advantage one gets with a more
expensive bike. Let's say someone can bike 100 miles in 5 or 6 hours on
a $300 road bike that weighs 22 lb (say flat, no wind). What would be
the difference if he
rides 100 miles on a $1000 bike instead? How much time could he shave
off, with the same effort (if possible to estimate at all)? |
i**********g
发帖数: 159 | 2 My opinion. It probably will be a big difference if you compare $1000 to a $
300 bike. Not only the weight. The accuracy and efficiency of power train.
How well the bike fits you. Assume you have enough power, if the the handle
bar and the saddle are not that comfortable, it will be very painful or
impossible to ride 100 miles. Not saying nobody have done a century ride on
a walmart bike, but it just could've been much easier and more comfortable
if you have a nicer bike.
The weight affects more |
n******d
发帖数: 3583 | 3 多花点钱，可以保证能买到更轻的车，但是花同样的钱，体重却不是一定能减少的。呵
呵，个人认为，还是要看骑车的目的，如果是纯竞技为目的的，轻个2，3磅，绝对对成
绩会有改善，试想那怎么都是多把2，3磅的东西搬100mile。但如果是锻炼健身为目
的，就无所谓，多了就当是负重练习，增加了强度而已。
如果要分析，先说如下概念：
动能：
物体由于运动而具有的能叫动能，它通常被定义成使某物体从静止状态至运动状态所做的功。它的大小是运动物体的质量和速度平方乘积的二分之一。Ek=(1/2)×m×v^2
动能定理：
力在一个过程中对物体所做的功等于在这个过程中动能的变化。合外力(物体所受的外力的总和,根据方向以及受力大小通过正交法能计算出物体最终的合力方向及大小) 对物体所做的功等于物体动能的变化。
所以粗略套公式，可以看出，如果维持同样速度，人的重量是150lbs,骑18lbs比骑22lbs的动能要少3.5%，也就是可以少做3.5%的功，省力3.5%。
如果做同样的功，那么速度就会快大概1.8%
哈哈，好像是这么说的。
......
ride
the
......
【在 i**********g 的大作中提到】
: My opinion. It probably will be a big difference if you compare $1000 to a $
: 300 bike. Not only the weight. The accuracy and efficiency of power train.
: How well the bike fits you. Assume you have enough power, if the the handle
: bar and the saddle are not that comfortable, it will be very painful or
: impossible to ride 100 miles. Not saying nobody have done a century ride on
: a walmart bike, but it just could've been much easier and more comfortable
: if you have a nicer bike.
: The weight affects more
|
h******2
发帖数: 1498 | 4 here is a short answer: say you can cruise at 20mph with a $300 bike (which
is impressive), then you can easily cruise at 21mph with a $1k bike. on a
100 mile flat, that's 15 minutes. with a $3k bike, you can probably cruise
at 21.5mph, that's another 6 minutes less.
now if the course includes climbing, compare the 22lb $300 bike with a 14.
5lb $3k bike, you can probably shave off more than 30 minutes with the $3k
bike. |
w****1
发帖数: 4931 | 5 Thanks, that's an extremely helpful answer! My $300 bike from bikesdirect (
which is claimed to be of $700
value) feels pretty good.:) It's a little heavier than my former $100 second
hand road bike, but it feels super
smooth and fast -- probably because I never had a real good bike. I will
take a ride with my GPS after getting
my bike out of the bikeshop Tuesday (it needs a full body tune-up).
which
cruise
【在 h******2 的大作中提到】
: here is a short answer: say you can cruise at 20mph with a $300 bike (which
: is impressive), then you can easily cruise at 21mph with a $1k bike. on a
: 100 mile flat, that's 15 minutes. with a $3k bike, you can probably cruise
: at 21.5mph, that's another 6 minutes less.
: now if the course includes climbing, compare the 22lb $300 bike with a 14.
: 5lb $3k bike, you can probably shave off more than 30 minutes with the $3k
: bike.
|
w****1
发帖数: 4931 | 6 My $300 bike is as comfortable as I could ask for right now. Maybe I'll change
my mind after riding a 100-miler.
But I believe it's no walmart bike.:)
$
handle
on
ride
the
【在 i**********g 的大作中提到】
: My opinion. It probably will be a big difference if you compare $1000 to a $
: 300 bike. Not only the weight. The accuracy and efficiency of power train.
: How well the bike fits you. Assume you have enough power, if the the handle
: bar and the saddle are not that comfortable, it will be very painful or
: impossible to ride 100 miles. Not saying nobody have done a century ride on
: a walmart bike, but it just could've been much easier and more comfortable
: if you have a nicer bike.
: The weight affects more
|
w****1
发帖数: 4931 | 7
Indeed, if I only wanted to burn some calories I wouldn't care. What I'm
wondering is whether I need to think
about investing on a more expensive bike in order to do an ironman. I
probably won't do it if it only shaves off
10 minutes in a 112-mile bike ride. But a 30 minutes difference would be big
enough for me to consider
some investment.
I'm a physicist so I fully understand the mechanics. But I don't fully
understand how my body works in cycling
which is why I ask experienced cyclists.:) Al
【在 n******d 的大作中提到】
: 多花点钱，可以保证能买到更轻的车，但是花同样的钱，体重却不是一定能减少的。呵
: 呵，个人认为，还是要看骑车的目的，如果是纯竞技为目的的，轻个2，3磅，绝对对成
: 绩会有改善，试想那怎么都是多把2，3磅的东西搬100mile。但如果是锻炼健身为目
: 的，就无所谓，多了就当是负重练习，增加了强度而已。
: 如果要分析，先说如下概念：
: 动能：
: 物体由于运动而具有的能叫动能，它通常被定义成使某物体从静止状态至运动状态所做的功。它的大小是运动物体的质量和速度平方乘积的二分之一。Ek=(1/2)×m×v^2
: 动能定理：
: 力在一个过程中对物体所做的功等于在这个过程中动能的变化。合外力(物体所受的外力的总和,根据方向以及受力大小通过正交法能计算出物体最终的合力方向及大小) 对物体所做的功等于物体动能的变化。
: 所以粗略套公式，可以看出，如果维持同样速度，人的重量是150lbs,骑18lbs比骑22lbs的动能要少3.5%，也就是可以少做3.5%的功，省力3.5%。
|
n******d
发帖数: 3583 | 8 嗬嗬，没想到班门弄斧了，见笑了。
big
are huge factors.
肯定只有在同样的条件下才有比较的意义，在一百迈中，如何补充水分和电解质都会有
很大的影响。最好的方法还是实际测试一下，呵呵
【在 w****1 的大作中提到】
:
: Indeed, if I only wanted to burn some calories I wouldn't care. What I'm
: wondering is whether I need to think
: about investing on a more expensive bike in order to do an ironman. I
: probably won't do it if it only shaves off
: 10 minutes in a 112-mile bike ride. But a 30 minutes difference would be big
: enough for me to consider
: some investment.
: I'm a physicist so I fully understand the mechanics. But I don't fully
: understand how my body works in cycling
|
c********6
发帖数: 3483 | 9 说到tuned-up，各位大虾认为值得吗？
我只是看了youtube自己搞了一下
bikesdirect (
second
【在 w****1 的大作中提到】
: Thanks, that's an extremely helpful answer! My $300 bike from bikesdirect (
: which is claimed to be of $700
: value) feels pretty good.:) It's a little heavier than my former $100 second
: hand road bike, but it feels super
: smooth and fast -- probably because I never had a real good bike. I will
: take a ride with my GPS after getting
: my bike out of the bikeshop Tuesday (it needs a full body tune-up).
:
: which
: cruise
|
h******2
发帖数: 1498 | 10 if you have to "think" about "investing" in a new, more expensive bike, you'
re not ready for it. even if you buy it, it rides you, instead you riding
it.
you'll be ready for an upgrade when you keep telling yourself "i want it, i
have to get myself a new bike, really bad." and when you actually go out
and buy a more expensive bike, you will immediately put it to work and beat
the shit out of it.
about the kinetic energy analysis, it is inaccurate.
when we talk about cruising at a constant s
【在 w****1 的大作中提到】
:
: Indeed, if I only wanted to burn some calories I wouldn't care. What I'm
: wondering is whether I need to think
: about investing on a more expensive bike in order to do an ironman. I
: probably won't do it if it only shaves off
: 10 minutes in a 112-mile bike ride. But a 30 minutes difference would be big
: enough for me to consider
: some investment.
: I'm a physicist so I fully understand the mechanics. But I don't fully
: understand how my body works in cycling
|
|
|
h******2
发帖数: 1498 | 11 for your new bike, no.
you will probably need a fitting (which is the adjustment of the seat and
handle bar so that the bike fits better your body geometry)
【在 c********6 的大作中提到】
: 说到tuned-up，各位大虾认为值得吗？
: 我只是看了youtube自己搞了一下
:
: bikesdirect (
: second
|
n******d
发帖数: 3583 | 12 Thanks so much! It is a good question indeed. I learned a lot from hengmei
too. |
h******2
发帖数: 1498 | 13 more about the physics -- it's the power output of the body that counts.
power equals force times velocity, P=F*V. at constant high speed, force is
mostly a function of wind resistance, which in turn is proportional to V^2.
i.e., F=a*V^2+b*V.
so, to maintain a certain speed, your body's power output is approximately
proportional to (a*V^3+b*V^2). that's why it's a lot harder to increase
your speed from 20mph to 23mph than from 17mph to 20mph, because at higher
speed your power output is going |
w********6
发帖数: 12977 | 14 my $400 BD bike work fine as well, it worthwhile for us to get full benefit
from this tuition before we know exactly what we need.
It's easy to understand a lighter bike, but it takes time to understand what
it means to you for a few lbs lighter, and also takes to understand what's
the benefit of more efficient power transition (for example BB30), what's
the befit of smoother gear shifting, ....of quicker response, ...of stiffer
frame, etc.
In my opinion you only need to upgrade when you know ex
【在 w****1 的大作中提到】
: Just want to have an idea how much advantage one gets with a more
: expensive bike. Let's say someone can bike 100 miles in 5 or 6 hours on
: a $300 road bike that weighs 22 lb (say flat, no wind). What would be
: the difference if he
: rides 100 miles on a $1000 bike instead? How much time could he shave
: off, with the same effort (if possible to estimate at all)?
|
w****1
发帖数: 4931 | 15 At the moment I don't have cycling shoes (was gonna ride in my asics) and I
haven't bothered to install the
straps on my pedals. How important are these? I'd imagine that they don't
have all these fancy stuff 25 years
ago and were able to do the ironman just fine.
the proper pedaling technique from the get-go.
【在 h******2 的大作中提到】
: more about the physics -- it's the power output of the body that counts.
: power equals force times velocity, P=F*V. at constant high speed, force is
: mostly a function of wind resistance, which in turn is proportional to V^2.
: i.e., F=a*V^2+b*V.
: so, to maintain a certain speed, your body's power output is approximately
: proportional to (a*V^3+b*V^2). that's why it's a lot harder to increase
: your speed from 20mph to 23mph than from 17mph to 20mph, because at higher
: speed your power output is going
|
w****g
发帖数: 78 | 16 别不知足了，我老人家从来没有骑过公路车，从来没有买过专业服装，从来没有参加过
比赛。我的车很重，山地车，还经常用那对忒别肥的外胎
另外我的体重不到100斤
是不是该去跳楼了 |
w****g
发帖数: 78 | 17 上下坡多，顶风很痛苦，尤其是看到人家骑赛车很轻松的从我身边飞过 |
w****1
发帖数: 4931 | 18 dude, I don't care how much you suck. I would like to learn from the
better. It doesn't make me feel better by comparing to the worse.
【在 w****g 的大作中提到】
: 别不知足了，我老人家从来没有骑过公路车，从来没有买过专业服装，从来没有参加过
: 比赛。我的车很重，山地车，还经常用那对忒别肥的外胎
: 另外我的体重不到100斤
: 是不是该去跳楼了
|
w********6
发帖数: 12977 | 19 it is important when you are riding fast or go up steep hills, for pulling
is something you can only do when you have clipless.
In my opinion, it is more helpful than Garmin. Without Garmin people were
riding fine for decades if not centuries, but certainly you won't regret
your garmin.
I
【在 w****1 的大作中提到】
: At the moment I don't have cycling shoes (was gonna ride in my asics) and I
: haven't bothered to install the
: straps on my pedals. How important are these? I'd imagine that they don't
: have all these fancy stuff 25 years
: ago and were able to do the ironman just fine.
:
: the proper pedaling technique from the get-go.
|
w****1
发帖数: 4931 | 20 I haven't realized that I'm supposed to pull the pedal. I thought it would
strain the knee in a bad way. So how is the clipless pedal compare to pedals
with straps? What is the difference exactly?
【在 w********6 的大作中提到】
: it is important when you are riding fast or go up steep hills, for pulling
: is something you can only do when you have clipless.
: In my opinion, it is more helpful than Garmin. Without Garmin people were
: riding fine for decades if not centuries, but certainly you won't regret
: your garmin.
:
: I
|
|
|
w********6
发帖数: 12977 | 21 i dont' have experience with straps, but what i heard is clipless is safer
and better tech than strap.
when you are pulling you can achieve more balanced pedaling. of course, the
better way to explain the pedaling is like you are trying to scrap off the
dog shit you got in your shoe
pedals
【在 w****1 的大作中提到】
: I haven't realized that I'm supposed to pull the pedal. I thought it would
: strain the knee in a bad way. So how is the clipless pedal compare to pedals
: with straps? What is the difference exactly?
|
w********6
发帖数: 12977 | 22 when i got my BD bike, i was riding with my asics for two months and then
decide to give clipless a try, i bought a eggbeater (actually designed
for mtn bike but i like its design) and i will never go back.
even though clipless is not very convenient in commuting, but now i already
get used to it. |
h******2
发帖数: 1498 | 23 how important? on a scale of 1 to 10, i'll give it a 10.
you wouldn't run with shoes based on a 25-year old technology, right?
similarly, you don't want to ride with pedals based on a 75-year old
technology. plus, the cage/strap are not supposed to go with sneakers, they
are meant to go with hard-soled special (although old fashioned) cycling
shoes.
also, you can re-use the pedals and shoes with your next bike.
I
【在 w****1 的大作中提到】
: At the moment I don't have cycling shoes (was gonna ride in my asics) and I
: haven't bothered to install the
: straps on my pedals. How important are these? I'd imagine that they don't
: have all these fancy stuff 25 years
: ago and were able to do the ironman just fine.
:
: the proper pedaling technique from the get-go.
|
w****1
发帖数: 4931 | 24 Actually, I'm trying to practice running based on 10,000 yr old technology -
barefoot.:)
So the biking shoes are important, but what about strap vs clipless pedal?
Do I really need to buy a new pair of
pedals before going for my first 100-miler?
they
【在 h******2 的大作中提到】
: how important? on a scale of 1 to 10, i'll give it a 10.
: you wouldn't run with shoes based on a 25-year old technology, right?
: similarly, you don't want to ride with pedals based on a 75-year old
: technology. plus, the cage/strap are not supposed to go with sneakers, they
: are meant to go with hard-soled special (although old fashioned) cycling
: shoes.
: also, you can re-use the pedals and shoes with your next bike.
:
: I
|
h******2
发帖数: 1498 | 25 for a 100-miler, absolutely yes.
you probably want to do a 20 miler first to see if the seat and handle bar
position fits. |
w****1
发帖数: 4931 | 26 That's good to know. Thanks!
【在 h******2 的大作中提到】
: for a 100-miler, absolutely yes.
: you probably want to do a 20 miler first to see if the seat and handle bar
: position fits.
|
C**********y
发帖数: 78 | 27 The integration of the your feet to the pedal using strap is not nearly as
good as the clipless. Therefore, the power transfer will not be as
efficient using straps. On the other hand, it does require some practice to
get use to the in and out tricks of using the clipless. I have yet seen one
using clipless without falling, regardless their experiences. Having said
that as a newbie myslef, I just bought a $7 clip & strap will be used on my
10+ years old Specialized Hardrock and log some miles
【在 w****1 的大作中提到】
: Actually, I'm trying to practice running based on 10,000 yr old technology -
: barefoot.:)
: So the biking shoes are important, but what about strap vs clipless pedal?
: Do I really need to buy a new pair of
: pedals before going for my first 100-miler?
:
: they
|
c*******r
发帖数: 13580 | 28 Clipless for sure. It's hard to pull with cage. Cages don't position your
feet on the pedals precisely either. For a century, it makes a world of
difference.
-
【在 w****1 的大作中提到】
: Actually, I'm trying to practice running based on 10,000 yr old technology -
: barefoot.:)
: So the biking shoes are important, but what about strap vs clipless pedal?
: Do I really need to buy a new pair of
: pedals before going for my first 100-miler?
:
: they
|
