maximum weight on a Bianchi Eros frame.

[TLOlczyk]

Ok. For about the last nine months I've been sidelined with some real
nasty Achilles tendonitis. That ( plus a change in medications to one
that causes weight gain ) has caused my weight to really scoot up.
Now that the pain is subsiding, and I am ready to get back on a bike
can someone tell me what the maximum weight that the frame on a
Bianchi Eros can handle is?

Thanks



The reply-to email address is [email protected].
This is an address I ignore.
To reply via email, remove 2002 and change yahoo to
interaccess,

**
Thaddeus L. Olczyk, PhD

There is a difference between
*thinking* you know something,
and *knowing* you know something.

 

[Chalo]

TLOlczyk wrote:
>
> Ok. For about the last nine months I've been sidelined with some real
> nasty Achilles tendonitis. That ( plus a change in medications to one
> that causes weight gain ) has caused my weight to really scoot up.
> Now that the pain is subsiding, and I am ready to get back on a bike
> can someone tell me what the maximum weight that the frame on a
> Bianchi Eros can handle is?

The frame can carry pretty much whatever you put on it, for a while at
least. (Remember the Viet Cong hauling 500 lbs. or more along unpaved
roads on old French road bikes?) It's the wheels, and the square taper
crank if it has one, that are at the most risk of failure from heavy
loads. Next in line is probably the fork steerer. (If you have an
Eros with a carbon/aluminum fork, I wouldn't be surprised if Bianchi
were willing to specify a weight limit for the fork, if you ask.)

This all presupposes that you are riding in a controlled fashion over
relatively good surfaces. For example, I managed to trash more frames
when I weighed in the mid-200s than later when I weighed in the
mid-300s, through a combination of highly athletic riding, lots of
miles, and inadvisable hijinks.

The couple of frame failures I have experienced while weighing above
350 lbs. have been sudden and dramatic. Both occurred while braking
hard with a special brake of my own design, though, and I don't believe
they would have been caused by the use of any commercially available
brake.

I wouldn't worry too much about it at this point. If your wheels fail
quickly, then you can concern yourself with what might go next. But if
they hold up OK, then I doubt you will have other structural problems.


Do switch to some kind of tubular spindle crank if your bike is
equipped with a square taper, though. When those things snap off-- and
that is the only way they fail structurally-- you can get seriously
hurt. One of the new 2-piece cranks with outboard-mounted BB bearings
would be a good choice.

Keep in mind that the risks you assume by not getting enough exercise
may be much graver than the risks you assume by riding a flimsy
bicycle. To mitigate both kinds of risk, however, you can always
upgrade to a sturdier bike.

Chalo Colina

 

[Qui si parla Campagnolo]

Chalo wrote:
> TLOlczyk wrote:
> >
> > Ok. For about the last nine months I've been sidelined with some real
> > nasty Achilles tendonitis. That ( plus a change in medications to one
> > that causes weight gain ) has caused my weight to really scoot up.
> > Now that the pain is subsiding, and I am ready to get back on a bike
> > can someone tell me what the maximum weight that the frame on a
> > Bianchi Eros can handle is?
>

>
>
> Do switch to some kind of tubular spindle crank if your bike is
> equipped with a square taper, though. When those things snap off-- and
> that is the only way they fail structurally-- you can get seriously
> hurt. One of the new 2-piece cranks with outboard-mounted BB bearings
> would be a good choice.

Maybe you ought to see how much the gent weighs before you assume that
a square taper crank/BB will be unsafe. Many have ridden square taper
w/o problem for decades, and to paint it as 'unsafe' for nearly anybody
is not accurate.

In 20 years I have seen 3 BB square tapers break. I have also seen 2
octalink break and we will have to see about the two piece systems, as
they have only been around for 3 years so far.
>
> Keep in mind that the risks you assume by not getting enough exercise
> may be much graver than the risks you assume by riding a flimsy
> bicycle. To mitigate both kinds of risk, however, you can always
> upgrade to a sturdier bike.
>
> Chalo Colina

 

[[email protected]]

Chalo wrote:
> The frame can carry pretty much whatever you put on it, for a while at
> least. (Remember the Viet Cong hauling 500 lbs. or more along unpaved
> roads on old French road bikes?) It's the wheels, and the square taper
> crank if it has one, that are at the most risk of failure from heavy
> loads.

How exactly will a heavy load affect the bottom bracket spindle? I
would think the bottom bracket spindle is affected only by the amount
of force/power the motor/rider can put into it while turning the
cranks. No matter what load is being supported above the ground by the
frame and wheels, it does not cause the motor/rider to produce more
power/strength and stress the bottom bracket more.

 

[Llatikcuf]

Chalo wrote:
>
>
> This all presupposes that you are riding in a controlled fashion over
> relatively good surfaces. For example, I managed to trash more frames
> when I weighed in the mid-200s than later when I weighed in the
> mid-300s, through a combination of highly athletic riding, lots of
> miles, and inadvisable hijinks.
>
> The couple of frame failures I have experienced while weighing above
> 350 lbs. have been sudden and dramatic. Both occurred while braking
> hard with a special brake of my own design, though, and I don't believe
> they would have been caused by the use of any commercially available
> brake.
>

Highly athletic at 350lbs?

 

[[email protected]]

Llatikcuf wrote:
> Chalo wrote:
> >
> >
> > This all presupposes that you are riding in a controlled fashion over
> > relatively good surfaces. For example, I managed to trash more frames
> > when I weighed in the mid-200s than later when I weighed in the
> > mid-300s, through a combination of highly athletic riding, lots of
> > miles, and inadvisable hijinks.
> >
> > The couple of frame failures I have experienced while weighing above
> > 350 lbs. have been sudden and dramatic. Both occurred while braking
> > hard with a special brake of my own design, though, and I don't believe
> > they would have been caused by the use of any commercially available
> > brake.
> >
>
> Highly athletic at 350lbs?

Re-read the post. He did highly athletic riding when he weighed in the
mid 200s. As compared to when he weighed in the mid 300s. He broke
more frames when weighing less, mid 200s, than when he weighed more,
mid 300s. Weight is not the only or main reason frames break.

 

[Chalo]

Qui si parla Campagnolo wrote:
>
> Chalo wrote:
> >
> >
> > Do switch to some kind of tubular spindle crank if your bike is
> > equipped with a square taper, though. When those things snap off-- and
> > that is the only way they fail structurally-- you can get seriously
> > hurt. One of the new 2-piece cranks with outboard-mounted BB bearings
> > would be a good choice.
>
> Maybe you ought to see how much the gent weighs before you assume that
> a square taper crank/BB will be unsafe. Many have ridden square taper
> w/o problem for decades, and to paint it as 'unsafe' for nearly anybody
> is not accurate.

As I've told you before, I have broken two square tapers under pedaling
loads alone; one when I weighed about 240 lbs., and the other when I
weighed about 260 lbs.

IMO this is not so far out of the normal range that the square taper
can be considered safe. The OP does consider himself enough heavier
than average to pose the question.

> In 20 years I have seen 3 BB square tapers break. I have also seen 2
> octalink break and we will have to see about the two piece systems, as
> they have only been around for 3 years so far.

That's not terribly surprising about Octalink (it being a Shimano
product after all), but I did assume that the feeble little crankarm
splines would strip before the "pipe spindle" snapped.

Chalo Colina

 

[Chalo]

[email protected] wrote:
>
> Chalo wrote:
> > The frame can carry pretty much whatever you put on it, for a while at
> > least. (Remember the Viet Cong hauling 500 lbs. or more along unpaved
> > roads on old French road bikes?) It's the wheels, and the square taper
> > crank if it has one, that are at the most risk of failure from heavy
> > loads.
>
> How exactly will a heavy load affect the bottom bracket spindle? I
> would think the bottom bracket spindle is affected only by the amount
> of force/power the motor/rider can put into it while turning the
> cranks. No matter what load is being supported above the ground by the
> frame and wheels, it does not cause the motor/rider to produce more
> power/strength and stress the bottom bracket more.

The load in this case is the rider. The rider can load the BB spindle
in three primary ways: Asymmetric torque from pedaling forces on the
left side, symmetric torque from standing with pedals level, and
bending loads that are applied whenever either pedal has any force on
it (in any crank orientation) and whenever the chain has any tension on
it.

A heavy rider increases the magnitude of all three of these loads
compared to a lighter rider.

If the load on a bike is in the form of luggage or the like, then of
course the BB spindle will not be affected by that.

Chalo Colina

 

[Chalo]

Llatikcuf wrote:
>
> Chalo wrote:
> >
> >
> > This all presupposes that you are riding in a controlled fashion over
> > relatively good surfaces. For example, I managed to trash more frames
> > when I weighed in the mid-200s than later when I weighed in the
> > mid-300s, through a combination of highly athletic riding, lots of
> > miles, and inadvisable hijinks.
> >
> > The couple of frame failures I have experienced while weighing above
> > 350 lbs. have been sudden and dramatic. Both occurred while braking
> > hard with a special brake of my own design, though, and I don't believe
> > they would have been caused by the use of any commercially available
> > brake.
> >
>
> Highly athletic at 350lbs?

I didn't say that.

However, since I'm 6'8" with a sturdy frame (and used to be even
taller), 300 lbs. represents a fit and strong weight for me. At 350+
lbs., I'm rather fat but still physically active and capable of
vigorous riding.

If you refer to the simple geometric principle that volume is
propotional to height^3, then you'll see that 6'8" and 300 lbs is
equivalent to 6'0" and 219 lbs., or 5'6" and 168 lbs. That's normal
for fit men of heavy build at those heights.

At my leanest (due to a combination of fanatical riding, vegan diet,
and "ethnopharmacology"), I measured 6'9" and about 220 lbs. That's
equivalent to 6'0" and 155 lbs., and it's not an ideal weight for
someone of naturally heavy build. I'm quite a lot stronger at 300 lbs
than at 220.

If you have had a failure of imagination about my physical scale, don't
feel bad about it. Bike, car, and airplane manufacturers do it all the
time.

Chalo Colina

 

[Llatikcuf]

>If you refer to the simple geometric principle that volume is
>proportional to height^3, then you'll see that 6'8" and 300 lbs is
>equivalent to 6'0" and 219 lbs., or 5'6" and 168 lbs. That's normal
>for fit men of heavy build at those heights.

that's not how I remember health class-

http://www.intmed.mcw.edu/clincalc/body.html

6' 8" 300# = BMI of 33
6' 0" 219# = BMI of 29.7
5' 6" 168# = BMI of 27.1

Not equivalent in my book

Equivalent would be:

6' 0" 243# BMI of 33
5' 6" 205# BMI of 33

Just an observation.

 

[Chalo]

Llatikcuf wrote:
> >If you refer to the simple geometric principle that volume is
> >proportional to height^3, then you'll see that 6'8" and 300 lbs is
> >equivalent to 6'0" and 219 lbs., or 5'6" and 168 lbs. That's normal
> >for fit men of heavy build at those heights.
>
> that's not how I remember health class-
>
> http://www.intmed.mcw.edu/clincalc/body.html
>
> 6' 8" 300# = BMI of 33
> 6' 0" 219# = BMI of 29.7
> 5' 6" 168# = BMI of 27.1
>
> Not equivalent in my book
>
> Equivalent would be:
>
> 6' 0" 243# BMI of 33
> 5' 6" 205# BMI of 33
>
> Just an observation.

BMI is intrinsically flawed because it is geometrically erroneous.
What BMI purports to say is that a 1x1x1 cube is "underweight", a 2x2x2
cube is "normal", and a 3x3x3 cube is "morbidly obese". That's
ridiculous right on its face.

Chalo Colina

 

[Llatikcuf]

Chalo wrote:

> BMI is intrinsically flawed because it is geometrically erroneous.
> What BMI purports to say is that a 1x1x1 cube is "underweight", a 2x2x2
> cube is "normal", and a 3x3x3 cube is "morbidly obese". That's
> ridiculous right on its face.
>
> Chalo Colina

Ok, sounds good.

 

[Qui si parla Campagnolo]

Chalo wrote:
> Qui si parla Campagnolo wrote:
> >
> > Chalo wrote:
> > >
> > >
> > > Do switch to some kind of tubular spindle crank if your bike is
> > > equipped with a square taper, though. When those things snap off-- and
> > > that is the only way they fail structurally-- you can get seriously
> > > hurt. One of the new 2-piece cranks with outboard-mounted BB bearings
> > > would be a good choice.
> >
> > Maybe you ought to see how much the gent weighs before you assume that
> > a square taper crank/BB will be unsafe. Many have ridden square taper
> > w/o problem for decades, and to paint it as 'unsafe' for nearly anybody
> > is not accurate.
>
> As I've told you before, I have broken two square tapers under pedaling
> loads alone; one when I weighed about 240 lbs., and the other when I
> weighed about 260 lbs.
>
> IMO this is not so far out of the normal range that the square taper
> can be considered safe. The OP does consider himself enough heavier
> than average to pose the question.

And as I have mentioned, there is something amiss in the ones you used
and I do not think it's a design flaw. Many as heavy and strong as you
or more so, have used square taper for decades w/o any failures.
>
> > In 20 years I have seen 3 BB square tapers break. I have also seen 2
> > octalink break and we will have to see about the two piece systems, as
> > they have only been around for 3 years so far.
>
> That's not terribly surprising about Octalink (it being a Shimano
> product after all), but I did assume that the feeble little crankarm
> splines would strip before the "pipe spindle" snapped.
>
> Chalo Colina

 

[David Damerell]

Quoting Llatikcuf <[email protected]>:
>>If you refer to the simple geometric principle that volume is
>>proportional to height^3, then you'll see that 6'8" and 300 lbs is
>>equivalent to 6'0" and 219 lbs., or 5'6" and 168 lbs. That's normal
>>for fit men of heavy build at those heights.
>that's not how I remember health class-
[BMI]

Indeed, it is obvious that BMI is bogus for people of unusual height
precisely because it does not take account of the square-cube law.
--
David Damerell <[email protected]> Distortion Field!
Today is First Mania, July.

 

[41]

Chalo wrote:

> However, since I'm 6'8" with a sturdy frame (and used to be even
> taller)

> At my leanest (due to a combination of fanatical riding, vegan diet,
> and "ethnopharmacology"), I measured 6'9" and about 220 lbs.

Hmmm. You're not geriatric; could you explain that please? Is it the
extra 100+lbs compressing you down? If so, the relevant parameter would
be torso (better, spinal column) length, not overall body length. Since
you were a fanatical bike rider you might know this figure for the two
cases. Any comments?


About BMI vs cubic law: a mouse, rat, pig, or super-morbidly obese
person is starting to approximate a cube or an oblate spheroid
http://tinyurl.com/bhskg
but a lean person is not. Both cube laws and the BMI are just
approximations, neither of which is perfect.

http://tinyurl.com/76ng8
http://www.halls.md/bmi/history.htm

BMI is pretty good, and people are interested in it not because of any
geometrical rationalization, but because it is easy to calculate from
available data and seems well correlated with % body fat and health and
lifespan. However, there is enough scatter in the data for outliers
such as yourself. %BF and especially how much you've got around the
middle are the most relevant known parameters. Special K "pinch more
than an inch" test also not too bad.a

 

[David Damerell]

Quoting 41 <[email protected]>:
>About BMI vs cubic law: a mouse, rat, pig, or super-morbidly obese
>person is starting to approximate a cube or an oblate spheroid

But the square-cube law has nothing to do with the actual shape of the
body in question.
--
David Damerell <[email protected]> Distortion Field!
Today is First Mania, July.

 

[[email protected]]

On 21 Jul 2005 17:16:24 +0100 (BST), David Damerell
<[email protected]> wrote:

>Quoting 41 <[email protected]>:
>>About BMI vs cubic law: a mouse, rat, pig, or super-morbidly obese
>>person is starting to approximate a cube or an oblate spheroid
>
>But the square-cube law has nothing to do with the actual shape of the
>body in question.

Dear David,

Aha! It's a law!

So that's why a tall giraffe weighs more than a shorter
elephant!

And why a twenty-foot tapeworm weighs more than a ten-foot
python!

And why I weigh more than a 600-lb gorilla!

Carl Fogel

 

[Chalo]

41 wrote:
>
> Chalo wrote:
> >
> > However, since I'm 6'8" with a sturdy frame (and used to be even
> > taller)
>
> > At my leanest (due to a combination of fanatical riding, vegan diet,
> > and "ethnopharmacology"), I measured 6'9" and about 220 lbs.
>
> Hmmm. You're not geriatric; could you explain that please? Is it the
> extra 100+lbs compressing you down? If so, the relevant parameter would
> be torso (better, spinal column) length, not overall body length. Since
> you were a fanatical bike rider you might know this figure for the two
> cases. Any comments?

Once you stop getting taller, you start getting shorter, regardless of
age. It's more pronounced for me than for many other folks probably
because I broke my back in two places as a teenager, but no doubt also
due to my unusual height and weight.

I have never known my back length; only overall height and standing
inseam. But since my inseam has not noticeably changed and my overall
height has, that sort of narrows down the possibilities.

Perhaps it's my head getting flatter? :^)

> About BMI vs cubic law: a mouse, rat, pig, or super-morbidly obese
> person is starting to approximate a cube or an oblate spheroid
> http://tinyurl.com/bhskg
> but a lean person is not.

It doesn't matter what the shape is, volume is still directly
proportional to the cube of the length.

> Both cube laws and the BMI are just
> approximations, neither of which is perfect.

Not perfect, sure, but consider this: If two bodies are exactly
identical in every respect except overall scale, then BMI considers one
of them to have a "better" weight than the other. Obviously this is
fallacious.

> BMI is pretty good, and people are interested in it not because of any
> geometrical rationalization, but because it is easy to calculate from
> available data and seems well correlated with % body fat and health and
> lifespan.

Unusually tall height is correlated with shortened lifespan, but it's
simply wrong to think that a very tall person will live longer by being
underweight and thus having a "normal" BMI. I would expect the
opposite. Likewise, very short people live longer on average than
normal-sized people, but it would not be to their benefit to gain
weight in order to normalize their BMI.

Anyway, if BMI is fundamentally a statistical tool, then it's bogus to
use a purely geometrical (and purely broken) formula to calculate it.
The more you look at it, the more it looks like plain old hokum.

Chalo Colina

 

[Peter Cole]

David Damerell wrote:
> Quoting Llatikcuf <[email protected]>:
>
>>>If you refer to the simple geometric principle that volume is
>>>proportional to height^3, then you'll see that 6'8" and 300 lbs is
>>>equivalent to 6'0" and 219 lbs., or 5'6" and 168 lbs. That's normal
>>>for fit men of heavy build at those heights.
>>
>>that's not how I remember health class-
>
> [BMI]
>
> Indeed, it is obvious that BMI is bogus for people of unusual height
> precisely because it does not take account of the square-cube law.

We've been over this before. BMI works for me (6'10"/230lb), so does the
max HR formula. As unusual as I am statistically, I'm only 17% or so
taller than the average male of European descent, probably less than
that for my ancestral gene pool (Dutch). As far as I know, I'm to scale,
in that all my parts, including eyes (opthalmologist says) and teeth/jaw
(dentist says) are just that much bigger. I'm no "bean pole", nobody
ever called me skinny, I'd say I have an average build/frame, just
scaled up a bit. For my average build, the BMI seems to scale well,
perhaps not perfectly, as my body fat is low-ish and the BMI has me at
the high end of normal/recommended. 17% isn't a huge difference
geometrically (although it seems huge to most people appearance-wise).
Another non-linearity is density -- bones get bigger/heavier as they get
longer, though I'm not sure exactly how much. It's interesting to see
such physically different cyclists as Pantani/Hamilton vs.
Hincapie/Indurain compete over the same courses. It seems there may be a
disadvantage to being too big or too small when it comes to endurance
athletics.

There is a wide variation in build/body types. I guess the old
endo/ecto/meso-morph type model is no longer used, but I've seen a few
attempts to adjust the BMI for categories of body type.

More importantly, there was just a study that linked large skull size to
high intelligence. This pleases me because I can never find a hat big
enough either.

 

[Chalo]

Qui si parla Campagnolo wrote:
>
> Chalo wrote:
> >
> > Qui si parla Campagnolo wrote:
> > >
> > >
> > > Maybe you ought to see how much the gent weighs before you assume that
> > > a square taper crank/BB will be unsafe. Many have ridden square taper
> > > w/o problem for decades, and to paint it as 'unsafe' for nearly anybody
> > > is not accurate.
> >
> > As I've told you before, I have broken two square tapers under pedaling
> > loads alone; one when I weighed about 240 lbs., and the other when I
> > weighed about 260 lbs.
>
> And as I have mentioned, there is something amiss in the ones you used
> and I do not think it's a design flaw.

I was willing to believe that after I broke the first one. I continued
to use a square taper and it cost me my six top front teeth. I would
be a damn fool to give a proven piece of junk like that another chance
to hurt me-- as would anybody over 220 lbs., in my opinion.

> Many as heavy and strong as you
> or more so, have used square taper for decades w/o any failures.

And several people who post here in this group have broken them. It's
not rare and it's the result of just plain bad engineering.

Chalo Colina