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Date: 15 Apr 2007 07:46:12
From: Robert Larson
Subject: Anyone experience loss of control (ie crash) from bridge road vibration
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Fri AM I was making my typical commute to work. A block before my office
is a bridge with a metal grate for a road bed (perhaps 3" squares?). I
have ridden my bike over this bridge at least 100 times with almost no
problems. A few times I have felt a very brief shimmy of my front wheel,
but always have regained control in a split second in rain or shine.
On Friday I felt my front wheel begin to shimmy immediately. I was
constantly trying to regain control and nearly went over on both left
and right sides a couple times. I finally did lose control and remember
that grating coming at me as I fell. I was wearing my helmet albiet I
did not hit my head. My right forearm though took a beating and I
received a bone chip on my elbow. I spent the morning at the ER getting
a deep wound cleaned, xrays, tetanus shot, antibiotics (dirty bridge :)
), and pain pills.
Thank God the driver behind me stopped with ample room (his vehicle was
slightly touched by the car behind him). He helped me off the roadway
and called my office as my cell phone was destroyed, and I was in shock
and not sure could have called.
The real reason for this post isn't for sympathy (but it is welcome :) )
but to see if there may be a reason this happened this time. BTW, I will
walk this stretch in the future.
Bike: Hybrid
Tires: Not skinny, not mountain (bike at work so can;t check now)
Filled tubes that AM to max psi (6 on whatever that 'other' scale is)
Two panniers
Differences:
One pannier heavier than usual so slightly unbalanced, although I have
ridden at times with only one heavy pannier with no problem.
LOTS of big concrete trucks on roadway at time - I think moving slowly.
It is a two lane each direction draw bridge. Bridge was recently
retrofit for streetcars in the middle of roadway. Regular service of
streetcars began a week ago. There may have been a streetcar or two on
bridge.
Maybe it was a coincidence waiting to happen - maybe something else.
Ideas? Similar experiences?
TIA
Robert
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Date: 15 Apr 2007 15:36:19
From: Mark Hickey
Subject: Re: Anyone experience loss of control (ie crash) from bridge road vibration
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Robert Larson <robert@rlarson.com > wrote:
>Fri AM I was making my typical commute to work. A block before my office
>is a bridge with a metal grate for a road bed (perhaps 3" squares?). I
>have ridden my bike over this bridge at least 100 times with almost no
>problems. A few times I have felt a very brief shimmy of my front wheel,
>but always have regained control in a split second in rain or shine.
>
>On Friday I felt my front wheel begin to shimmy immediately. I was
>constantly trying to regain control and nearly went over on both left
>and right sides a couple times. I finally did lose control and remember
>that grating coming at me as I fell. I was wearing my helmet albiet I
>did not hit my head. My right forearm though took a beating and I
>received a bone chip on my elbow. I spent the morning at the ER getting
>a deep wound cleaned, xrays, tetanus shot, antibiotics (dirty bridge :)
>), and pain pills.
<snip >
>Ideas? Similar experiences?
I had one "major pucker moment" on a tandem in Florida, on a similar
steel grate bridge. My wife and I were cranking up over the small
hill before the bridge at a pretty good clip (somewhere around 20mph.
There was a very light drizzle that had just started falling, and
apparently this liberated the oil that was on the steel. So now we
found ourselves trying to balance on tiny, oily, wet pieces of steel.
I felt the back wheel break loose, and yelled "don't move" to my wife
(who knew to do just that). As I corrected for the rear wheel slide,
I felt the front wheel break loose. We went across the second half of
the grating sliding one way and then the other - but thankfully never
too far off-axis, and I was able to keep the bike upright (you do NOT
want to go down on that "cheese-grinder surface" on a tandem.
Very likely you encountered a bit of oil during your crash - when that
happens, there's almost no lateral stability, and the front tire is
likely to skate far enough to make the slide unrecoverable.
Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame
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Date: 15 Apr 2007 12:56:33
From: jbollyn@gmail.com
Subject: Re: Anyone experience loss of control (ie crash) from bridge road vibration
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On Apr 15, 9:46 am, Robert Larson <rob...@rlarson.com > wrote:
> Fri AM I was making my typical commute to work. A block before my office
> is a bridge with a metal grate for a road bed (perhaps 3" squares?). I
> have ridden my bike over this bridge at least 100 times with almost no
> problems. A few times I have felt a very brief shimmy of my front wheel,
> but always have regained control in a split second in rain or shine.
>
> On Friday I felt my front wheel begin to shimmy immediately. I was
> constantly trying to regain control and nearly went over on both left
> and right sides a couple times. I finally did lose control and remember
> that grating coming at me as I fell. I was wearing my helmet albiet I
> did not hit my head. My right forearm though took a beating and I
> received a bone chip on my elbow. I spent the morning at the ER getting
> a deep wound cleaned, xrays, tetanus shot, antibiotics (dirty bridge :)
> ), and pain pills.
>
> Thank God the driver behind me stopped with ample room (his vehicle was
> slightly touched by the car behind him). He helped me off the roadway
> and called my office as my cell phone was destroyed, and I was in shock
> and not sure could have called.
>
> The real reason for this post isn't for sympathy (but it is welcome :) )
> but to see if there may be a reason this happened this time. BTW, I will
> walk this stretch in the future.
>
> Bike: Hybrid
> Tires: Not skinny, not mountain (bike at work so can;t check now)
> Filled tubes that AM to max psi (6 on whatever that 'other' scale is)
> Two panniers
>
> Differences:
> One pannier heavier than usual so slightly unbalanced, although I have
> ridden at times with only one heavy pannier with no problem.
>
> LOTS of big concrete trucks on roadway at time - I think moving slowly.
> It is a two lane each direction draw bridge. Bridge was recently
> retrofit for streetcars in the middle of roadway. Regular service of
> streetcars began a week ago. There may have been a streetcar or two on
> bridge.
>
> Maybe it was a coincidence waiting to happen - maybe something else.
>
> Ideas? Similar experiences?
>
> TIA
> Robert
Hi Robert,
We have a few of those bridges in downtown Chicago, over the Chicago
River. They are not on my daily commute, but every once in awhile I
have found myself on one of them. My strong feeling is, they are not
suitable for ANY bike traffic. My BF has 20" wheels, 1.5" tires. The
vibration is very bad, and if you need to turn right or left suddenly,
you will be really stressed.
I have had my share of bike wrecks with personal injury (to myself).
They have always been my fault, for just being reckless.
My suggestion is, as you say - use another route, or walk it across
the bridge - J.
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Date: 15 Apr 2007 20:54:27
From: Mike Kruger
Subject: Re: Anyone experience loss of control (ie crash) from bridge road vibration
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jbollyn@gmail.com wrote:
> Robert Larson <rob...@rlarson.com> wrote:
> On Apr 15, 9:46 am, Robert Larson <rob...@rlarson.com> wrote:
>> Fri AM I was making my typical commute to work. A block before my
>> office is a bridge with a metal grate for a road bed
>
> We have a few of those bridges in downtown Chicago, over the Chicago
> River. They are not on my daily commute, but every once in awhile I
> have found myself on one of them. My strong feeling is, they are not
> suitable for ANY bike traffic. My BF has 20" wheels, 1.5" tires. The
> vibration is very bad, and if you need to turn right or left suddenly,
> you will be really stressed.
>
On at least one bridge in Chicago there is a bike-friendly strip over such a
bridge.
This is due to a campaign by Kathy Schubert, who had a similar accident. The
story is available if you scroll down a few inches here:
http://www.biketraffic.org/biketraffic/BT0105/
I'm not sure how widespread these are in Chicago because there aren't any on
my standard routes; if I'd seen this message earlier, I could have asked
Kathy yesterday -- we were on the same ride.
The last time I went over the Well St. bridge the strip was still there, but
it's not on my ordinary route.
The point to mentioning this is
1. There is a solution.
2. The efforts of one persistent person can get the solution adopted. It's
possible the O.P., together with the local bicycle club, might be able to
get this sort of modest improvement implemented.
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Date: 15 Apr 2007 15:36:55
From: Steve knight
Subject: Re: Anyone experience loss of control (ie crash) from bridge road vibration
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metal is bad for traction any moisture and it is very slippery. myself
I would not ride on that surface unless I absolutely had too just too
dangerous.
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Date: 15 Apr 2007 15:27:11
From: Robert Larson
Subject: Re: Anyone experience loss of control (ie crash) from bridge road
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Mike,
Thanks for this link. I had planned to contact the SF Bike Coalition
tomorrow regarding this. I will also contact a friend that sometimes
does bridge consulting work.
Robert
Mike Kruger wrote:
> jbollyn@gmail.com wrote:
>
>>Robert Larson <rob...@rlarson.com> wrote:
>>On Apr 15, 9:46 am, Robert Larson <rob...@rlarson.com> wrote:
>>
>>>Fri AM I was making my typical commute to work. A block before my
>>>office is a bridge with a metal grate for a road bed
>>
>>We have a few of those bridges in downtown Chicago, over the Chicago
>>River. They are not on my daily commute, but every once in awhile I
>>have found myself on one of them. My strong feeling is, they are not
>>suitable for ANY bike traffic. My BF has 20" wheels, 1.5" tires. The
>>vibration is very bad, and if you need to turn right or left suddenly,
>>you will be really stressed.
>>
>
> On at least one bridge in Chicago there is a bike-friendly strip over such a
> bridge.
> This is due to a campaign by Kathy Schubert, who had a similar accident. The
> story is available if you scroll down a few inches here:
>
> http://www.biketraffic.org/biketraffic/BT0105/
>
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