How Did I Dent My BIke? Please Read and Suggest

[James Lynx]

Okay,

It's actually my girlfriend's bike. A Trek 4100 13 inch bike. She
was riding for an hour. We put it on the bike rack on the car and I
dropped her off at her place and drove back to my place. After I
took the bike off the rack I didn't notice any dents. I rode it for
about a couple of minutes. Sure I'm taller and don't ride a 13 inch
bike. My frame is 19 inch. I have a Fuji Discovery II but wanted to
try her bike. I got off and noticed a small dent about half the size
of a dime (please don't say a nickel!). Very small. Now mind you
before we put it on the car rack we didn't notice it and I didn't
notice it when I took it off the rack. It could have been dented by
the rack sure and I didn't notice it but I think I would have noticed
it because I did notice it after I rode it. I am 200 LBS. Could my
weight have caused a small dent in the frame? It's the lower tube not
the top tube. Or do you think it's more likely loading it on the bike
rack would cause such a dent rather than me riding the bike? Sure I'm
200 LBS but why should I be able to cause a dent by my weight. How
weak are these bikes? I know you weren't there but I'm giving you the
scenario and maybe you can help with the likelyhood of different
causes.




Thanks,



James

 

[Chuck W]

"James Lynx" <[email protected]> wrote in message
news:[email protected]...
> Okay,
>
> It's actually my girlfriend's bike. A Trek 4100 13 inch bike. She
> was riding for an hour. We put it on the bike rack on the car and I
> dropped her off at her place and drove back to my place. After I
> took the bike off the rack I didn't notice any dents. I rode it for
> about a couple of minutes. Sure I'm taller and don't ride a 13 inch
> bike. My frame is 19 inch. I have a Fuji Discovery II but wanted to
> try her bike. I got off and noticed a small dent about half the size
> of a dime (please don't say a nickel!). Very small. Now mind you
> before we put it on the car rack we didn't notice it and I didn't
> notice it when I took it off the rack. It could have been dented by
> the rack sure and I didn't notice it but I think I would have noticed
> it because I did notice it after I rode it. I am 200 LBS. Could my
> weight have caused a small dent in the frame? It's the lower tube not
> the top tube. Or do you think it's more likely loading it on the bike
> rack would cause such a dent rather than me riding the bike? Sure I'm
> 200 LBS but why should I be able to cause a dent by my weight. How
> weak are these bikes? I know you weren't there but I'm giving you the
> scenario and maybe you can help with the likelyhood of different
> causes.
>
>
>
>
> Thanks,
>
>
>
> James

That really depends on exactly where the dent is on the down tube, and where
else you've inspected for damage. If your weight caused the frame to begin
buckling (which is hard to imagine just riding around a bit with no crazy
stuff involved), then the top tube should have visible signs of the same
type of buckling as well, or there should be cracks forming at the welds
between the frame members in one or more places.

If you don't see any of that, I'd say you just dinged it on something.

-Chuck W

 

[S o r n i]

James Lynx wrote:
> Okay,
>
> It's actually my girlfriend's bike. A Trek 4100 13 inch bike. She
> was riding for an hour. We put it on the bike rack on the car and I
> dropped her off at her place and drove back to my place. After I
> took the bike off the rack I didn't notice any dents. I rode it for
> about a couple of minutes. Sure I'm taller and don't ride a 13 inch
> bike. My frame is 19 inch. I have a Fuji Discovery II but wanted to
> try her bike. I got off and noticed a small dent about half the size
> of a dime (please don't say a nickel!). Very small. Now mind you
> before we put it on the car rack we didn't notice it and I didn't
> notice it when I took it off the rack. It could have been dented by
> the rack sure and I didn't notice it but I think I would have noticed
> it because I did notice it after I rode it. I am 200 LBS. Could my
> weight have caused a small dent in the frame? It's the lower tube not
> the top tube. Or do you think it's more likely loading it on the bike
> rack would cause such a dent rather than me riding the bike? Sure I'm
> 200 LBS but why should I be able to cause a dent by my weight. How
> weak are these bikes? I know you weren't there but I'm giving you the
> scenario and maybe you can help with the likelyhood of different
> causes.

What type of rack -- fork mount or one of those clamps that hold the
downtube?

Back in '96, a friend was putting my brand-new (well, almost) Fisher Paragon
up on his rack -- it was a Ford Bronco II so I had to hand it up him -- and
then I heard him say, "Oh-oh". The friggin' clamp put a crimp in my
downtube.

Rode it that way for a few years until the frame cracked near the
headtube/downtube junction (but not at a weld); got it replaced under
warranty and still (hardly ever) ride it today.

Bill "ugly '98 black/yellow instead of the loud '99 yellow-red scheme frame
(original was a deep blue)" S.

 

[Matthew Paterson]

On Mon, 31 May 2004 20:14:37 -0700, James Lynx wrote:

> It's actually my girlfriend's bike.

Dude, your not getting any nookie for like a month!

--
Matt

Fear of a flat planet

 

[Pippen]

"James Lynx" <[email protected]> wrote in message
news:[email protected]...
> Okay,
>
> It's actually my girlfriend's bike. A Trek 4100 13 inch bike. She
> was riding for an hour. We put it on the bike rack on the car and I
> dropped her off at her place and drove back to my place. After I
> took the bike off the rack I didn't notice any dents. I rode it for
> about a couple of minutes. Sure I'm taller and don't ride a 13 inch
> bike. My frame is 19 inch. I have a Fuji Discovery II but wanted to
> try her bike. I got off and noticed a small dent about half the size
> of a dime (please don't say a nickel!). Very small. Now mind you
> before we put it on the car rack we didn't notice it and I didn't
> notice it when I took it off the rack. It could have been dented by
> the rack sure and I didn't notice it but I think I would have noticed
> it because I did notice it after I rode it. I am 200 LBS. Could my
> weight have caused a small dent in the frame? It's the lower tube not
> the top tube. Or do you think it's more likely loading it on the bike
> rack would cause such a dent rather than me riding the bike? Sure I'm
> 200 LBS but why should I be able to cause a dent by my weight. How
> weak are these bikes? I know you weren't there but I'm giving you the
> scenario and maybe you can help with the likelyhood of different
> causes.
>
>
>
>
> Thanks,
>
>
>
> James

My guess is that someone dented the down tube. My assumptions are you rode
it around the parking lot with out running into anything with the front
wheel.

Reason 1:
The downtube has a elongation forces when only riding the bike around while
the top tube has compression forces. Denting would be the first signs of a
crumpling effect caused by compression forces. I would expect to see that on
the top tube not on the down tube from you being to heavy for the bike.

Reason 2:
At that level of a bike I doubt that the wall thinkness for the tube set is
any different than that for let's say a 19 inch bike. A smaller frame should
be stonger than a larger frame given the same thickness in the tube set.
Even if the tube set it double or triple butted the smaller frame should be
stronger.

Of couse if what you mean by "I rode it for about a couple of minutes."
means down a set of stairs with a four foot wall at the end then yes you may
have dented it with your wieght...

-p

 

[James Lynx]

Pippen from what you and others describe I can be confident that I did
not dent the tube by my weight. I must have dented it placing it on
the bike rack.

For the above poster who asked what kind of rack it is. Well, it's on
the back of the mini van and you place the top tubes over two
individual arms so to speak. I'm new to the whole bike rack thing so
I don't even know proper names for this stuff. I must have pushed
the bottom tube into the rack arm pretty hard or something. The bike
will be fine because it's a really small dent anyway. And yes only
rode in the parking lot a few minutes and rode on the street for a few
minutes. No jumping off of rocks or riding down stairs.


Thanks all for all the input here.



Thanks,


James




"Pippen" <[email protected]> wrote in message news:<QC0vc.30182$js4.26893@attbi_s51>...
> "James Lynx" <[email protected]> wrote in message
> news:[email protected]...
> > Okay,
> >
> > It's actually my girlfriend's bike. A Trek 4100 13 inch bike. She
> > was riding for an hour. We put it on the bike rack on the car and I
> > dropped her off at her place and drove back to my place. After I
> > took the bike off the rack I didn't notice any dents. I rode it for
> > about a couple of minutes. Sure I'm taller and don't ride a 13 inch
> > bike. My frame is 19 inch. I have a Fuji Discovery II but wanted to
> > try her bike. I got off and noticed a small dent about half the size
> > of a dime (please don't say a nickel!). Very small. Now mind you
> > before we put it on the car rack we didn't notice it and I didn't
> > notice it when I took it off the rack. It could have been dented by
> > the rack sure and I didn't notice it but I think I would have noticed
> > it because I did notice it after I rode it. I am 200 LBS. Could my
> > weight have caused a small dent in the frame? It's the lower tube not
> > the top tube. Or do you think it's more likely loading it on the bike
> > rack would cause such a dent rather than me riding the bike? Sure I'm
> > 200 LBS but why should I be able to cause a dent by my weight. How
> > weak are these bikes? I know you weren't there but I'm giving you the
> > scenario and maybe you can help with the likelyhood of different
> > causes.
> >
> >
> >
> >
> > Thanks,
> >
> >
> >
> > James
>
> My guess is that someone dented the down tube. My assumptions are you rode
> it around the parking lot with out running into anything with the front
> wheel.
>
> Reason 1:
> The downtube has a elongation forces when only riding the bike around while
> the top tube has compression forces. Denting would be the first signs of a
> crumpling effect caused by compression forces. I would expect to see that on
> the top tube not on the down tube from you being to heavy for the bike.
>
> Reason 2:
> At that level of a bike I doubt that the wall thinkness for the tube set is
> any different than that for let's say a 19 inch bike. A smaller frame should
> be stonger than a larger frame given the same thickness in the tube set.
> Even if the tube set it double or triple butted the smaller frame should be
> stronger.
>
> Of couse if what you mean by "I rode it for about a couple of minutes."
> means down a set of stairs with a four foot wall at the end then yes you may
> have dented it with your wieght...
>
> -p