Bike Weight -- uphill TT

Art M said:

I just completed an uphill time trial approx. 8% grade for
7 miles on a 26.5 lb bike. Does anyone have a formula that
would tell me how much my time would have improved on a
competitive bike (resulting in a ~5% reduction in overall
weight)?

This has been done to death many times before here, for the
various threads, do a Google groups search.Basically, the 5%
reduction (1.5lb?) in bike weight will give you virtually
nil advantage in the real world. Aero-dynamics and fitness
are what improve time-trials. To get your bike faster, get
some aero wheels, which may actually make your bike heavier,
but the bike will go faster, even on a 7mile 8% hill over
26miles. See this site for some ideas:
softride.comtriAero.aspOpen ↗ There are loads of
other sites detailing the same sort of thing. Alan.

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"A.Lee" <alan@darkroom.+.com> wrote in message
"]news:[email hidden]...

Quoted message said:

Art M said:

I just completed an uphill time trial approx. 8% grade
for 7 miles on a

26.5

Quoted message said:

Quoted message said:

lb bike. Does anyone have a formula that would tell me
how much my time would have improved on a competitive
bike (resulting in a ~5% reduction

in

Quoted message said:

Quoted message said:

overall weight)?

This has been done to death many times before here, for
the various threads, do a Google groups search.Basically,
the 5% reduction (1.5lb?) in bike weight will give you
virtually nil advantage in the real world. Aero-dynamics
and fitness are what improve time-trials. To get your bike
faster, get some aero wheels, which may actually make your
bike heavier, but the bike will go faster, even on a 7mile
8% hill over 26miles. See this site for some ideas:
softride.comtriAero.aspOpen ↗ There are loads
of other sites detailing the same sort of thing. Alan.

I'm about to check out your link, but bear in mind that this
was just uphill (the complete course was 7 miles long, all
uphill -- ave grade ~8%, 20% max, my ave speed a bit over 8
mph). Are you telling me that at that speed bike weight
(when climbing) matters less than aerodynamics?

--Art

"A.Lee" <alan@darkroom.+.com> wrote in message
"]news:[email hidden]...

Quoted message said:

Art M said:

I just completed an uphill time trial approx. 8% grade
for 7 miles on a

26.5

Quoted message said:

Quoted message said:

lb bike. Does anyone have a formula that would tell me
how much my time would have improved on a competitive
bike (resulting in a ~5% reduction

in

Quoted message said:

Quoted message said:

overall weight)?

This has been done to death many times before here, for
the various threads, do a Google groups search.Basically,
the 5% reduction (1.5lb?) in bike weight

ALSO, it's a 10 lb reduction in bike weight (many bikes
these days are a bit over 16 lbs, no?) resulting in a 5%
reduction in rider+bike weight.

--Art

A.Lee alan@darkroom.+.com said:

On Mon, 03 May 2004 14:21:23 +0000, Art M wrote:

Quoted message said:

Quoted message said:

I just completed an uphill time trial approx. 8% grade
for 7 miles on a 26.5 lb bike. Does anyone have a
formula that would tell me how much my time would have
improved on a competitive bike (resulting in a ~5%
reduction in overall weight)?

Quoted message said:

This has been done to death many times before here, for
the various threads, do a Google groups search.Basically,
the 5% reduction (1.5lb?) in bike weight will give you
virtually nil advantage in the real world. Aero-dynamics
and fitness are what improve time-trials. To get your bike
faster, get some aero wheels, which may actually make your
bike heavier, but the bike will go faster, even on a 7mile
8% hill over 26miles.

That's daft. You don't need aerodynamics on a 7 mile, 8% all
uphill TT.

His bike already weighs 26.5 lbs. An 18 lb bike would
definitely make a significant improvement.

To the OP: Try www.analyticcycling.com

Art Harris

Art M said:

"A.Lee" <alan@darkroom.+.com> wrote in message
"]news:[email hidden]...

Quoted message said:

Art M said:

I just completed an uphill time trial approx. 8% grade
for 7 miles on a
26.5lb bike. Does anyone have a formula that would tell
me how much my time would have improved on a
competitive bike (resulting in a ~5% reduction in
overall weight)?

Basically, the 5% reduction (1.5lb?) in bike weight will
give you virtually nil advantage in the real world. Aero-
dynamics and fitness are what improve time-trials. To get
your bike faster, get some aero wheels, which may
actually make your bike heavier, but the bike will go
faster, even on a 7mile 8% hill over 26miles.

I'm about to check out your link, but bear in mind that
this was just uphill (the complete course was 7 miles
long, all uphill -- ave grade ~8%, 20% max, my ave speed a
bit over 8 mph). Are you telling me that at that speed
bike weight (when climbing) matters less than
aerodynamics?

Sorry, I read it as a 7 mile climb during a 26mile TT. Go to
:analyticcycling.comWheelsClimb Page.htmlOpen ↗ and
type in all your details.I've just tried it, with a 65kg
rider, and a 1kg difference in 2 bikes, the 1kg bike comes
out as 27seconds faster over 10000metres,on a straight 8%
climb. Alan.

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"Harris" <[email hidden]> wrote in
message news:ajtlc.114$Jp.44735@ord-
read.news.verio.net... -snip-

Quoted message said:

His bike already weighs 26.5 lbs. An 18 lb bike would
definitely make a

significant improvement.

Quoted message said:

To the OP: Try www.analyticcycling.com

Art Harris

Thanks. I get a lot of ribbing about my bike. This is one
case where I was sure it hindered me, but I didn't want to
overestimate it.

It looks like at a power output of 250 to 200 watts I might
have seen a 2 to 3 minute improvement. That would have moved
me up the ranks.

--Art

No problem. I've made hasty replies before myself.

--Art

Art M said:

Thanks. I get a lot of ribbing about my bike. This is one
case where I was sure it hindered me, but I didn't want to
overestimate it.

It looks like at a power output of 250 to 200 watts I
might have seen a 2 to 3 minute improvement. That would
have moved me up the ranks.

It was wet last Thursday so I rode my touring bike in the
club "10". It's a flat course so the extra 10lb weight
didn't make much difference, but aerodynamically it's tragic
(fenders, rack, lights and three bottle cages) and the big
fat wheels don't help either. I was only 6 seconds slower
than on my racing bike. I suppose the moral is that the
rider, and how well he/she feels on the day, is more
important.

Quoted message said:

This has been done to death many times before here, for
the various threads, do a Google groups search.Basically,
the 5% reduction (1.5lb?)

Read the original post more carefully - the Op clearly means
5% of bike and rider, which is a lot more than 1.5lb. Figure
that we are talking 8lb difference between the OP's 26.5lb
clunker and a reasonably light road bike.

Quoted message said:

To get your bike faster, get some aero wheels, which may
actually make your bike heavier, but the bike will go
faster, even on a 7mile 8% hill over 26miles. See this
site for some ideas:
softride.comtriAero.aspOpen ↗

The figures at the above link show the opposite of what you
claim (using your figures, 1.5lb is not important). To
quote: "Only when the grade exceeds 3.7 percent does the
bike with lighter [by 400g, which is about 1lb] wheels have
the advantage".

--
Peter Headland

"Art M" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I just completed an uphill time trial approx. 8% grade for
7 miles on a 26.5 lb bike. Does anyone have a formula that
would tell me how much my time would have improved on a
competitive bike (resulting in a ~5% reduction in overall
weight)?

--Art

You haven't given enough info to determine this:
(1) what was your overall time ?
(2) what's your height and weight ?

An an estimate you'd go ~ 5 % faster (I'd say about a 2
minutes improvement in your time).

On 3 May 2004 11:59:09 -0700, [email hidden] (Peter Headland)

Quoted message said:

Quoted message said:

This has been done to death many times before here, for
the various threads, do a Google groups search.Basically,
the 5% reduction (1.5lb?)

Read the original post more carefully - the Op clearly
means 5% of bike and rider, which is a lot more than 1.5lb.
Figure that we are talking 8lb difference between the OP's
26.5lb clunker and a reasonably light road bike.

Quoted message said:

To get your bike faster, get some aero wheels, which may
actually make your bike heavier, but the bike will go
faster, even on a 7mile 8% hill over 26miles. See this
site for some ideas:
softride.comtriAero.aspOpen ↗

The figures at the above link show the opposite of what you
claim (using your figures, 1.5lb is not important). To
quote: "Only when the grade exceeds 3.7 percent does the
bike with lighter [by 400g, which is about 1lb] wheels have
the advantage".

Dear Peter,

While the effect of a small amount of weight is small, it's
still an effect. Given the same force, heavier objects
accelerate more slowly . Increased weight also increases
rolling resistance. Technically, adding a postage stamp will
have a postage-stamp sized effect.

To take the 1.5 pound example, assume a light bicycle and
rider that weigh only 150 pounds. The pound-and-a-half is
only 1%, so we he-man types at rec.bicycles.tech usually
dismiss it as negligible and snicker at the anorexic mind-
set of so many racers.

But 1% of a century ride is 5,280 feet--three minutes at 20
mph. And Armstrong keeps winning the Tour de France by less
than 10 minutes--less than 0.2% in 5,000+ minutes of racing.

In horse-racing, where far more power is available than in
bicycling, overall weight is far greater, much more money is
at stake, and what might be politely called irregularities
are not unknown, the officials still find it worth the
trouble to weigh the jockeys and their saddles to within a
pound, before and after the race:

Weighed in

All jockeys are weighed (with their saddles) before a race
to ensure they are carrying the correct weight - this is
known as "weighing out". After the race, jockeys who have
ridden a horse that is placed must then "weigh in". They
must not weigh in at more than a pound less than they
weighed out.

news.bbc.co.uk2Open ↗
964325.stm

Me, I carry four spare tubes and a spare tire on a fifteen-
mile ride. I suspect that they slow me down.

Carl Fogel

"Art M" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I just completed an uphill time trial approx. 8% grade for
7 miles on a 26.5 lb bike. Does anyone have a formula that
would tell me how much my time would have improved on a
competitive bike (resulting in a ~5% reduction in overall
weight)?

--Art

Unless you are a VERY light rider or you have a VERY heavy
bike, you can not achieve a 5% reduction in overall weight
from your bike alone.

If you calculate the % reduction in overall weight (rider
and bike) achieved by a reasonable reduction in the bike
weight, you'll see that it's not a big deal.

In article
<[email hidden]>,
[email hidden] says...

Quoted message said:

"Art M" <[email hidden]> wrote in
message news:<[email hidden]-
arthlink.net>...

Quoted message said:

I just completed an uphill time trial approx. 8% grade
for 7 miles on a 26.5 lb bike. Does anyone have a
formula that would tell me how much my time would have
improved on a competitive bike (resulting in a ~5%
reduction in overall weight)?

--Art

Unless you are a VERY light rider or you have a VERY heavy
bike, you can not achieve a 5% reduction in overall weight
from your bike alone.

A 170lb rider dropping from a 28lb bike to an 18lb bike will
drop more than 5% of total weight.

--
Remove the ns_ from if replying by e-mail (but keep posts in
the newsgroups if possible).

Quoted message said:

This has been done to death many times before here, for
the various threads, do a Google groups search.Basically,
the 5% reduction (1.5lb?) in bike weight will give you
virtually nil advantage in the real world. Aero-dynamics
and fitness are what improve time-trials. To get your bike
faster, get some aero wheels, which may actually make your
bike heavier, but the bike will go faster, even on a 7mile
8% hill over 26miles.

Hi Alan,

Your note reminded me of an article I read in Bicycling
Magazine. I found the issue I had in mind, it's September,
2003. I remembered it as I need to lose weight. It's from an
article on improving uphill performance. For what it's worth
I'll mention it here:

SPANK YOUR BAD SELF (basically saying - lose weight):
Here's the difference losing - or gaining - weight will
make on a 5 km
(3.1 mile) climb with an avg grade of 7%, assuming you put
out an avg of 250 watts. Even if your power never
increases, you climb about 30 seconds faster per 5 km for
every 5 pounds lost. Calculations performed for BICYCLING
by James C. Martin, Ph.D., assistant professor in the
department of exercise and sport science at the
University of Utah.

Cheers (with diet pop),

Neil

Quoted post said:

... course was 7 miles long, all
uphill -- ave grade ~8%, 20% max, my ave speed a bit over 8
mph).[/B]

On steep climbs where speeds are low, the resistive force is primarily gravity and your speed will be very nearly proportional to power/weight. So if you drop 5% of your total weight, and you maintain the same power, speed will go up by about 5% and you will drop about 5% off your time.

For more exact numbers that include air resistance and rolling resistance, use www.analyticcycling.com

arthur-<< I just completed an uphill time trial approx. 8%
grade for 7 miles on a 26.5 lb bike. Does anyone have a
formula that would tell me how much my time would have
improved on a competitive bike (resulting in a ~5% reduction
in overall weight)? >><BR><BR>

5% reduction of overall weight??you and your bike??

That's about a 10 pound reduction(assuming you weigh 170
pounds)...Anyway, less than 5% improvement. Less weight
improvement is not linear, assuming all else is equal, ride
to ride, and it never is.

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St.
Boulder, CO, 80302
(303)440-3535 vecchios.comvecchios.comOpen ↗ "Ruote convenzionali
costruite eccezionalmente bene"

Peter Chisolm said:

Less weight improvement is not linear, assuming all else
is equal, ride to ride, and it never is.

It is linear if the grade is steep enough, where almost all
the effort goes into lifting meat up the hill.
--
terry morse Palo Alto, CA bike.terrymorse.combike.terrymorse.comOpen ↗

A.Lee alan@darkroom.+.com said:

Art M said:

I just completed an uphill time trial approx. 8% grade for
7 miles on a 26.5 lb bike. Does anyone have a formula that
would tell me how much my time would have improved on a
competitive bike (resulting in a ~5% reduction in overall
weight)?

This has been done to death many times before here, for the
various threads, do a Google groups search.Basically, the
5% reduction (1.5lb?) in bike weight will give you
virtually nil advantage in the real world.

Not uphill, where a lot - even the majority - of effort is
going into overcoming gravity. In an extreme case a 5%
reduction in overall weight (not bike weight) might
produce a nearly 5% increase in speed, although an 8%
grade isn't it.

We can't, however, produce an estimate without knowing how
fast the OP went, since power to overcome gravity is linear
with speed, but to overcome air resistance power varies with
the cube of speed.
--
David Damerell <[email hidden]>
Distortion Field!

"Art M" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

I just completed an uphill time trial approx. 8% grade for
7 miles on a 26.5 lb bike. Does anyone have a formula that
would tell me how much my time would have improved on a
competitive bike (resulting in a ~5% reduction in overall
weight)?

On hills such as you have described, speed is very directly
proportional to the power-to-weight ratio, although this is
probably less so for a high level pro who can maintain a
higher speed (~14-15 mph) on such terrain so that
aerodynamics actually do come into play a bit more.

Last fall I had the opportunity to do an informal comparison
on one of the local passes. One day I was riding my road
bike, a couple of days later I was riding my mountain bike
carrying quite a bit more gear (cameras and such things, I
estimated the heavier bike and gear probably added 16 lbs to
the total weight going up the hill). On both rides I was
wearing a recording heart rate monitor and each climb was
ridden at essentially the same heart rate.

What was suprising was that the time on the heavy bike with
knobby tires was much closer to the time on the road bike
than I would have guessed it would be using a seat-of-the-
pants estimate. However when I actually did some
calculations, the time difference was very close to what
would be expected based upon the weight difference alone.

There's no question that weight makes a difference in the
hills, but it's also interesting to see just how little that
difference actually is in the real world. Or in other words,
pounds probably matter, grams probably don't.

DR