R
T
Tom Sherman
Guest
Richard Tack wrote:
> http://snipurl.com/akxe
Notice the tree is missing bark at about the level where the front tire
would hit. Any connection?
--
Tom Sherman
> http://snipurl.com/akxe
Notice the tree is missing bark at about the level where the front tire
would hit. Any connection?
--
Tom Sherman
R
Richard Tack
Guest
Tom Sherman wrote:
> Richard Tack wrote:
>
>> http://snipurl.com/akxe
>
>
> Notice the tree is missing bark at about the level where the front tire
> would hit. Any connection?
>
You'd think that the rim would be tacoed.
> Richard Tack wrote:
>
>> http://snipurl.com/akxe
>
>
> Notice the tree is missing bark at about the level where the front tire
> would hit. Any connection?
>
You'd think that the rim would be tacoed.
A
Alex Rodriguez
Guest
In article <P70ld.1652$fc.1296@trnddc09>, [email protected] says...
>
>
>Tom Sherman wrote:
>> Richard Tack wrote:
>>
>>> http://snipurl.com/akxe
>>
>>
>> Notice the tree is missing bark at about the level where the front tire
>> would hit. Any connection?
>>
>You'd think that the rim would be tacoed.
if he hit head on, this type of failure is not uncommon. Wheels are very
strong when the forces are inline with the wheel. It is usually offset forces
that damage a wheel.
--------------
Alex
>
>
>Tom Sherman wrote:
>> Richard Tack wrote:
>>
>>> http://snipurl.com/akxe
>>
>>
>> Notice the tree is missing bark at about the level where the front tire
>> would hit. Any connection?
>>
>You'd think that the rim would be tacoed.
if he hit head on, this type of failure is not uncommon. Wheels are very
strong when the forces are inline with the wheel. It is usually offset forces
that damage a wheel.
--------------
Alex
P
Pete Grey
Guest
I bent a very stout steel tandem downtube this way.
Car turned in front of us, front tire hit car fender basically straight-on,
downtube buckled, no appreciable wheel damage.
Buckle looked very similar to the pictures posted by Chalo in later posts.
-pete
"Alex Rodriguez" <[email protected]> wrote in message
news:[email protected]...
> In article <P70ld.1652$fc.1296@trnddc09>, [email protected]
> says...
>>
>>
>>Tom Sherman wrote:
>>> Richard Tack wrote:
>>>
>>>> http://snipurl.com/akxe
>>>
>>>
>>> Notice the tree is missing bark at about the level where the front tire
>>> would hit. Any connection?
>>>
>>You'd think that the rim would be tacoed.
>
> if he hit head on, this type of failure is not uncommon. Wheels are very
> strong when the forces are inline with the wheel. It is usually offset
> forces
> that damage a wheel.
> --------------
> Alex
>
Car turned in front of us, front tire hit car fender basically straight-on,
downtube buckled, no appreciable wheel damage.
Buckle looked very similar to the pictures posted by Chalo in later posts.
-pete
"Alex Rodriguez" <[email protected]> wrote in message
news:[email protected]...
> In article <P70ld.1652$fc.1296@trnddc09>, [email protected]
> says...
>>
>>
>>Tom Sherman wrote:
>>> Richard Tack wrote:
>>>
>>>> http://snipurl.com/akxe
>>>
>>>
>>> Notice the tree is missing bark at about the level where the front tire
>>> would hit. Any connection?
>>>
>>You'd think that the rim would be tacoed.
>
> if he hit head on, this type of failure is not uncommon. Wheels are very
> strong when the forces are inline with the wheel. It is usually offset
> forces
> that damage a wheel.
> --------------
> Alex
>
J
John McGraw
Guest
darrenf <[email protected]> wrote in message news:<[email protected]>...
> Alex Rodriguez Wrote:
> > In article <P70ld.1652$fc.1296@trnddc09>, [email protected]
> > says...
> > >
> > >
> > >Tom Sherman wrote:
> > >> Richard Tack wrote:
> > >>
> > >>> http://snipurl.com/akxe
> > >>
> > >>
> > >> Notice the tree is missing bark at about the level where the front
> tire
> > >> would hit. Any connection?
> > >>
> > >You'd think that the rim would be tacoed.
> >
> > if he hit head on, this type of failure is not uncommon. Wheels are
> > very
> > strong when the forces are inline with the wheel. It is usually offset
> > forces
> > that damage a wheel.
> > --------------
> > Alex
> Ouch
>
> That look painful and expensive
Oh, yah, how did the rider do? Hope his spine doesn't look like the top tube.
John
> Alex Rodriguez Wrote:
> > In article <P70ld.1652$fc.1296@trnddc09>, [email protected]
> > says...
> > >
> > >
> > >Tom Sherman wrote:
> > >> Richard Tack wrote:
> > >>
> > >>> http://snipurl.com/akxe
> > >>
> > >>
> > >> Notice the tree is missing bark at about the level where the front
> tire
> > >> would hit. Any connection?
> > >>
> > >You'd think that the rim would be tacoed.
> >
> > if he hit head on, this type of failure is not uncommon. Wheels are
> > very
> > strong when the forces are inline with the wheel. It is usually offset
> > forces
> > that damage a wheel.
> > --------------
> > Alex
> Ouch
>
> That look painful and expensive
Oh, yah, how did the rider do? Hope his spine doesn't look like the top tube.
John
C
Chalo
Guest
Richard Tack <[email protected]> wrote:
>
> http://snipurl.com/akxe
Wel, mine wasn't quite so bad as that... but then, I didn't run into
anything.
It's interesting to me that the tube of the Santa Cruz frame buckled
that far back from the joint as well. I guess I don't really have a
clear understanding of the stress distribution in the downtube under
that kind of load.
See my follow-up posting at
http://groups.google.com/[email protected]
or http://tinyurl.com/3oyxu
Chalo Colina
>
> http://snipurl.com/akxe
Wel, mine wasn't quite so bad as that... but then, I didn't run into
anything.
It's interesting to me that the tube of the Santa Cruz frame buckled
that far back from the joint as well. I guess I don't really have a
clear understanding of the stress distribution in the downtube under
that kind of load.
See my follow-up posting at
http://groups.google.com/[email protected]
or http://tinyurl.com/3oyxu
Chalo Colina
J
Pete Grey writes:
> >>>> http://snipurl.com/akxe
>>>> Notice the tree is missing bark at about the level where the
>>>> front tire would hit. Any connection?
>>> You'd think that the rim would be tacoed.
Ruining a frame that way takes far less force than one might imagine.
The wheel can take more than 400lbs force radially, while a frame can
withstand far less in that mode (directly from ahead) in bending of
the fork.
>> If he hit head on, this type of failure is not uncommon. Wheels
>> are very strong when the forces are inline with the wheel. It is
>> usually offset forces that damage a wheel.
> I bent a very stout steel tandem downtube this way. Car turned in
> front of us, front tire hit car fender basically straight-on,
> downtube buckled, no appreciable wheel damage.
> Buckle looked very similar to the pictures posted by Chalo in later
> posts.
However, the "buckle" on Chalo's Cannondale doesn't look like that.
Jobst Brandt
[email protected]
> >>>> http://snipurl.com/akxe
>>>> Notice the tree is missing bark at about the level where the
>>>> front tire would hit. Any connection?
>>> You'd think that the rim would be tacoed.
Ruining a frame that way takes far less force than one might imagine.
The wheel can take more than 400lbs force radially, while a frame can
withstand far less in that mode (directly from ahead) in bending of
the fork.
>> If he hit head on, this type of failure is not uncommon. Wheels
>> are very strong when the forces are inline with the wheel. It is
>> usually offset forces that damage a wheel.
> I bent a very stout steel tandem downtube this way. Car turned in
> front of us, front tire hit car fender basically straight-on,
> downtube buckled, no appreciable wheel damage.
> Buckle looked very similar to the pictures posted by Chalo in later
> posts.
However, the "buckle" on Chalo's Cannondale doesn't look like that.
Jobst Brandt
[email protected]
S
Sscarich
Guest
I don't know if this is relevant or not, but I was riding next to a guy last
Saturday who hit a pole at about 18 mph. He can't remember, but his helmet was
smashed on the left side, and his neck has a significant abrasion on the left
side. His front wheel is almost undamaged, and his frame appears to be O.K.
However, his carbon fork snapped almost symetrically, about 8" above the hub.
Our best guess is that he hit the pole almost dead center with his front tire,
and the fork took the brunt of the crash impact. He was one lucky guy. Minor
concussion, contussions on neck, and that's it.
Steve Scarich
Saturday who hit a pole at about 18 mph. He can't remember, but his helmet was
smashed on the left side, and his neck has a significant abrasion on the left
side. His front wheel is almost undamaged, and his frame appears to be O.K.
However, his carbon fork snapped almost symetrically, about 8" above the hub.
Our best guess is that he hit the pole almost dead center with his front tire,
and the fork took the brunt of the crash impact. He was one lucky guy. Minor
concussion, contussions on neck, and that's it.
Steve Scarich
P
Pih Stof
Guest
"Alex Rodriguez" <[email protected]> wrote in message
news:[email protected]...
> In article <P70ld.1652$fc.1296@trnddc09>, [email protected]
says...
> >
> >
> >Tom Sherman wrote:
> >> Richard Tack wrote:
> >>
> >>> http://snipurl.com/akxe
> >>
> >>
> >> Notice the tree is missing bark at about the level where the front tire
> >> would hit. Any connection?
> >>
> >You'd think that the rim would be tacoed.
>
> if he hit head on, this type of failure is not uncommon. Wheels are very
> strong when the forces are inline with the wheel. It is usually offset
forces
> that damage a wheel.
True, but enough force will flatten a wheel:
http://www.willisan.com/lib/bigwillistyle/cemetary.mpg
Needed one more bike length... ouch.
news:[email protected]...
> In article <P70ld.1652$fc.1296@trnddc09>, [email protected]
says...
> >
> >
> >Tom Sherman wrote:
> >> Richard Tack wrote:
> >>
> >>> http://snipurl.com/akxe
> >>
> >>
> >> Notice the tree is missing bark at about the level where the front tire
> >> would hit. Any connection?
> >>
> >You'd think that the rim would be tacoed.
>
> if he hit head on, this type of failure is not uncommon. Wheels are very
> strong when the forces are inline with the wheel. It is usually offset
forces
> that damage a wheel.
True, but enough force will flatten a wheel:
http://www.willisan.com/lib/bigwillistyle/cemetary.mpg
Needed one more bike length... ouch.
R
Richard Tack
Guest
Sscarich wrote:
> I don't know if this is relevant or not, but I was riding next to a guy last
> Saturday who hit a pole at about 18 mph. He can't remember, but his helmet was
> smashed on the left side, and his neck has a significant abrasion on the left
> side. His front wheel is almost undamaged, and his frame appears to be O.K.
> However, his carbon fork snapped almost symetrically, about 8" above the hub.
> Our best guess is that he hit the pole almost dead center with his front tire,
> and the fork took the brunt of the crash impact. He was one lucky guy. Minor
> concussion, contussions on neck, and that's it.
>
> Steve Scarich
Could the frangibilty of a carbon fork be
some kind of safety feature? IOW, it has a
greater ability to absorb energy than
steel or alum alloy?
> I don't know if this is relevant or not, but I was riding next to a guy last
> Saturday who hit a pole at about 18 mph. He can't remember, but his helmet was
> smashed on the left side, and his neck has a significant abrasion on the left
> side. His front wheel is almost undamaged, and his frame appears to be O.K.
> However, his carbon fork snapped almost symetrically, about 8" above the hub.
> Our best guess is that he hit the pole almost dead center with his front tire,
> and the fork took the brunt of the crash impact. He was one lucky guy. Minor
> concussion, contussions on neck, and that's it.
>
> Steve Scarich
Could the frangibilty of a carbon fork be
some kind of safety feature? IOW, it has a
greater ability to absorb energy than
steel or alum alloy?
W
Wasatch5k
Guest
> True, but enough force will flatten a wheel:
> http://www.willisan.com/lib/bigwillistyle/cemetary.mpg
> Needed one more bike length... ouch.
>
>
that's messed up
--
Let the bridges I burn light my way...
C
Chalo
Guest
[email protected] wrote:
>
> Pete Grey writes:
> >
> > I bent a very stout steel tandem downtube this way. Car turned in
> > front of us, front tire hit car fender basically straight-on,
> > downtube buckled, no appreciable wheel damage.
>
> > Buckle looked very similar to the pictures posted by Chalo in later
> > posts.
>
> However, the "buckle" on Chalo's Cannondale doesn't look like that.
Jobst, if I recall correctly, you ride a steel bike of conventional
construction and tubing diameters. Don't you find it unsurprising
that a thin-walled, huge diameter, conical tube would display a
different-looking failure mode? I find it a little disappointing that
the only alternate hypothesis you can offer is I must have slammed it
in a car door or the like.
I don't know why it seemed that the front wheel stopped and tossed me
over the bars, but I do know that it happened an instant after the
pictured frame failure occurred. So far I have three reasonable
possibilities: first, that the tire made contact withe the downtube
somehow without leaving a mark on the paint; second, that the frame's
failure caused a sudden shift in the front contact patch which made
the difference between hard deceleration and an endo; and third, that
some malfunction occurred in the brakes that was not obvious
afterwards when I was walking the bike home.
I am grateful for relevant observations, but I have already related
the circumstances of the failure. It was not a result of any object's
impact on the downtube unless that object was the front tire.
Chalo Colina
>
> Pete Grey writes:
> >
> > I bent a very stout steel tandem downtube this way. Car turned in
> > front of us, front tire hit car fender basically straight-on,
> > downtube buckled, no appreciable wheel damage.
>
> > Buckle looked very similar to the pictures posted by Chalo in later
> > posts.
>
> However, the "buckle" on Chalo's Cannondale doesn't look like that.
Jobst, if I recall correctly, you ride a steel bike of conventional
construction and tubing diameters. Don't you find it unsurprising
that a thin-walled, huge diameter, conical tube would display a
different-looking failure mode? I find it a little disappointing that
the only alternate hypothesis you can offer is I must have slammed it
in a car door or the like.
I don't know why it seemed that the front wheel stopped and tossed me
over the bars, but I do know that it happened an instant after the
pictured frame failure occurred. So far I have three reasonable
possibilities: first, that the tire made contact withe the downtube
somehow without leaving a mark on the paint; second, that the frame's
failure caused a sudden shift in the front contact patch which made
the difference between hard deceleration and an endo; and third, that
some malfunction occurred in the brakes that was not obvious
afterwards when I was walking the bike home.
I am grateful for relevant observations, but I have already related
the circumstances of the failure. It was not a result of any object's
impact on the downtube unless that object was the front tire.
Chalo Colina
E
Ed Chait
Guest
"Chalo" <[email protected]> wrote in message
news:[email protected]...
> I am grateful for relevant observations, but I have already related
> the circumstances of the failure. It was not a result of any object's
> impact on the downtube unless that object was the front tire.
>
> Chalo Colina
Does the load on the downtube change as the fork is compressed and shortened
under braking?
I would think the load would be less as the lever shortens, but I'm not an
ME. Perhaps there is a change in geometry that increases the load.
Ed Chait
news:[email protected]...
> I am grateful for relevant observations, but I have already related
> the circumstances of the failure. It was not a result of any object's
> impact on the downtube unless that object was the front tire.
>
> Chalo Colina
Does the load on the downtube change as the fork is compressed and shortened
under braking?
I would think the load would be less as the lever shortens, but I'm not an
ME. Perhaps there is a change in geometry that increases the load.
Ed Chait
P
Phil, Squid-in-Training
Guest
> True, but enough force will flatten a wheel:
> http://www.willisan.com/lib/bigwillistyle/cemetary.mpg
> Needed one more bike length... ouch.
It's obvious that the spokes weren't stress-relieved!
--
Phil, Squid-in-Training
> http://www.willisan.com/lib/bigwillistyle/cemetary.mpg
> Needed one more bike length... ouch.
It's obvious that the spokes weren't stress-relieved!
--
Phil, Squid-in-Training
J
Chalo Colina writes:
>>> I bent a very stout steel tandem downtube this way. Car turned in
>>> front of us, front tire hit car fender basically straight-on,
>>> downtube buckled, no appreciable wheel damage.
>>> Buckle looked very similar to the pictures posted by Chalo in
>>> later posts.
>> However, the "buckle" on Chalo's Cannondale doesn't look like that.
> Jobst, if I recall correctly, you ride a steel bike of conventional
> construction and tubing diameters. Don't you find it unsurprising
> that a thin-walled, huge diameter, conical tube would display a
> different-looking failure mode? I find it a little disappointing
> that the only alternate hypothesis you can offer is I must have
> slammed it in a car door or the like.
I don't see where you get that idea. I don't think I mentioned
anything about a collision with a solid object like a car.
> I don't know why it seemed that the front wheel stopped and tossed
> me over the bars, but I do know that it happened an instant after
> the pictured frame failure occurred.
I think you'll notice that this was not a "frame failure" but a small
damage to the downtube, one with which the bicycle was fully
functional and could be ridden with no change in perceptible riding
characteristics. The downtube was in perfect lateral alignment,
therefore having no effect on steering. Change in rake was so
minimal to be insignificant. That the strength of the tube was
compromised by the knick is obvious.
> So far I have three reasonable possibilities:
> first, that the tire made contact with the downtube somehow without
> leaving a mark on the paint;
That is possible but that case cannot be reconstructed according to
others who have seen the fork compressed and still leaving safe tire
clearance to the downtube. If this was the cause and the tire made
contact, there may still not have been a skid mark because the tire
was not rotating significantly... near lock-up anyway.
> second, that the frame's failure caused a sudden shift in the front
> contact patch which made the difference between hard deceleration
> and an endo;
That description escapes me. I can visualize that a sudden brake
application could stop the tire as the fork compresses but not at
30mph. If you mean that this was a typical endo cause by the rider
sliding off the saddle, yes that is a possibility, but that is a rider
induced event, not one of mechanical failure. The assumption was that
you are experienced enough to not cause such a crash... having
probably read about it here often enough.
http://draco.acs.uci.edu/rbfaq/FAQ/9.36.html
> third, that some malfunction occurred in the brakes that was not
> obvious afterwards when I was walking the bike home.
I assume you tried the brake or had someone else try that, but I don't
see any pointers to a brake lockup. Even that would not have caused
the dent in the downtube shown in the photos that is not a compression
wrinkle.
> I am grateful for relevant observations, but I have already related
> the circumstances of the failure. It was not a result of any
> object's impact on the downtube unless that object was the front
> tire.
As I pointed out, the words that you were tangled in the bicycle after
the crash gives rise to the possibility that the dent was cause after
the dismount and possibly by a shoe stuck between tire and downtube.
This dent appears as an embossed one made by a radial force on the
tube rather than a sliding contact such as a tire. Tire contact would
also have been about half way up between the dent and headtube.
Jobst Brandt
[email protected]
>>> I bent a very stout steel tandem downtube this way. Car turned in
>>> front of us, front tire hit car fender basically straight-on,
>>> downtube buckled, no appreciable wheel damage.
>>> Buckle looked very similar to the pictures posted by Chalo in
>>> later posts.
>> However, the "buckle" on Chalo's Cannondale doesn't look like that.
> Jobst, if I recall correctly, you ride a steel bike of conventional
> construction and tubing diameters. Don't you find it unsurprising
> that a thin-walled, huge diameter, conical tube would display a
> different-looking failure mode? I find it a little disappointing
> that the only alternate hypothesis you can offer is I must have
> slammed it in a car door or the like.
I don't see where you get that idea. I don't think I mentioned
anything about a collision with a solid object like a car.
> I don't know why it seemed that the front wheel stopped and tossed
> me over the bars, but I do know that it happened an instant after
> the pictured frame failure occurred.
I think you'll notice that this was not a "frame failure" but a small
damage to the downtube, one with which the bicycle was fully
functional and could be ridden with no change in perceptible riding
characteristics. The downtube was in perfect lateral alignment,
therefore having no effect on steering. Change in rake was so
minimal to be insignificant. That the strength of the tube was
compromised by the knick is obvious.
> So far I have three reasonable possibilities:
> first, that the tire made contact with the downtube somehow without
> leaving a mark on the paint;
That is possible but that case cannot be reconstructed according to
others who have seen the fork compressed and still leaving safe tire
clearance to the downtube. If this was the cause and the tire made
contact, there may still not have been a skid mark because the tire
was not rotating significantly... near lock-up anyway.
> second, that the frame's failure caused a sudden shift in the front
> contact patch which made the difference between hard deceleration
> and an endo;
That description escapes me. I can visualize that a sudden brake
application could stop the tire as the fork compresses but not at
30mph. If you mean that this was a typical endo cause by the rider
sliding off the saddle, yes that is a possibility, but that is a rider
induced event, not one of mechanical failure. The assumption was that
you are experienced enough to not cause such a crash... having
probably read about it here often enough.
http://draco.acs.uci.edu/rbfaq/FAQ/9.36.html
> third, that some malfunction occurred in the brakes that was not
> obvious afterwards when I was walking the bike home.
I assume you tried the brake or had someone else try that, but I don't
see any pointers to a brake lockup. Even that would not have caused
the dent in the downtube shown in the photos that is not a compression
wrinkle.
> I am grateful for relevant observations, but I have already related
> the circumstances of the failure. It was not a result of any
> object's impact on the downtube unless that object was the front
> tire.
As I pointed out, the words that you were tangled in the bicycle after
the crash gives rise to the possibility that the dent was cause after
the dismount and possibly by a shoe stuck between tire and downtube.
This dent appears as an embossed one made by a radial force on the
tube rather than a sliding contact such as a tire. Tire contact would
also have been about half way up between the dent and headtube.
Jobst Brandt
[email protected]
P
Phil, Squid-in-Training
Guest
> That is possible but that case cannot be reconstructed according to
> others who have seen the fork compressed and still leaving safe tire
> clearance to the downtube.
Suspension forks are much flexier than their rigid brethren. Take a
mountain bike with 28.6mm stanchions, hold the front brake, apply your body
weight to the pedals, and then hold the rear brake, too. Release pressure
on the pedals, and then release the front brake. I'm not sure if you ride
mountain bikes, Jobst, but sometimes the front wheel will move a 1/2 inch
under my 135 lbs. Chalo's 200% mass increase over mine may very well yield
enough force to bend a 30mm-stanchion suspension fork far enough to hit a
downtube.
However, Chalo did say that the crack occurred before the crash, and the
wrinkle may be suspect.
--
Phil, Squid-in-Training
> others who have seen the fork compressed and still leaving safe tire
> clearance to the downtube.
Suspension forks are much flexier than their rigid brethren. Take a
mountain bike with 28.6mm stanchions, hold the front brake, apply your body
weight to the pedals, and then hold the rear brake, too. Release pressure
on the pedals, and then release the front brake. I'm not sure if you ride
mountain bikes, Jobst, but sometimes the front wheel will move a 1/2 inch
under my 135 lbs. Chalo's 200% mass increase over mine may very well yield
enough force to bend a 30mm-stanchion suspension fork far enough to hit a
downtube.
However, Chalo did say that the crack occurred before the crash, and the
wrinkle may be suspect.
--
Phil, Squid-in-Training
T
Tom Sherman
Guest
Phil, Squid-in-Training wrote:
> Suspension forks are much flexier than their rigid brethren. Take a
> mountain bike with 28.6mm stanchions, hold the front brake, apply your body
> weight to the pedals, and then hold the rear brake, too. Release pressure
> on the pedals, and then release the front brake. I'm not sure if you ride
> mountain bikes, Jobst, but sometimes the front wheel will move a 1/2 inch
> under my 135 lbs. Chalo's 200% mass increase over mine may very well yield
> enough force to bend a 30mm-stanchion suspension fork far enough to hit a
> downtube....
The mass difference is closer to 280% (using values posted to r.b.t).
--
Tom Sherman
> Suspension forks are much flexier than their rigid brethren. Take a
> mountain bike with 28.6mm stanchions, hold the front brake, apply your body
> weight to the pedals, and then hold the rear brake, too. Release pressure
> on the pedals, and then release the front brake. I'm not sure if you ride
> mountain bikes, Jobst, but sometimes the front wheel will move a 1/2 inch
> under my 135 lbs. Chalo's 200% mass increase over mine may very well yield
> enough force to bend a 30mm-stanchion suspension fork far enough to hit a
> downtube....
The mass difference is closer to 280% (using values posted to r.b.t).
--
Tom Sherman
P
Peter
Guest
Tom Sherman wrote:
> Phil, Squid-in-Training wrote:
>
>> Suspension forks are much flexier than their rigid brethren. Take a
>> mountain bike with 28.6mm stanchions, hold the front brake, apply your
>> body weight to the pedals, and then hold the rear brake, too. Release
>> pressure on the pedals, and then release the front brake. I'm not
>> sure if you ride mountain bikes, Jobst, but sometimes the front wheel
>> will move a 1/2 inch under my 135 lbs. Chalo's 200% mass increase
>> over mine may very well yield enough force to bend a 30mm-stanchion
>> suspension fork far enough to hit a downtube....
>
>
> The mass difference is closer to 280% (using values posted to r.b.t).
>
Taking Phil's stated 135 lbs. and adding a mass (or weight) difference
of 280% (i.e. 378 more lbs.) would lead to a total for Chalo of 513 lbs.
I believe you are doing him an injustice. Even Phil's estimate of a
200% increase was a bit high for Chalo's current stated weight.
Perhaps you meant that the mass ratio is about 280%.
> Phil, Squid-in-Training wrote:
>
>> Suspension forks are much flexier than their rigid brethren. Take a
>> mountain bike with 28.6mm stanchions, hold the front brake, apply your
>> body weight to the pedals, and then hold the rear brake, too. Release
>> pressure on the pedals, and then release the front brake. I'm not
>> sure if you ride mountain bikes, Jobst, but sometimes the front wheel
>> will move a 1/2 inch under my 135 lbs. Chalo's 200% mass increase
>> over mine may very well yield enough force to bend a 30mm-stanchion
>> suspension fork far enough to hit a downtube....
>
>
> The mass difference is closer to 280% (using values posted to r.b.t).
>
Taking Phil's stated 135 lbs. and adding a mass (or weight) difference
of 280% (i.e. 378 more lbs.) would lead to a total for Chalo of 513 lbs.
I believe you are doing him an injustice. Even Phil's estimate of a
200% increase was a bit high for Chalo's current stated weight.
Perhaps you meant that the mass ratio is about 280%.
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