Balance

It's time for yet another one of my "foreigner in a strange land"
questions. I'm not entirely sure I agree with what the wrench is
saying, and I'd like to run it by people who know more and who know it
in English before spending money.

I crashed my bike about three weeks ago. As these things go it could
have been a lot more serious than it was but I wasn't going
particularly fast (22-23kph) and I had at least a few seconds warning
before I hit the idiot who was riding diagonally against traffic.

My front rim was bent beyond any thought of repair, the sidewall of my
rear tire had a number of small tears, and my helmet needed replacing.

I can't say I particularly noticed any difference in ride quality after
the crash. However, a few days ago when I was out on a borrowed
mountain bike I was riding handsfree and it suddenly occured to me that
I hadn't gone handsfree since the crash.

So, I tried it on my bike. And I couldn't. The bike kept wanting to
veer to the right.
Well, maybe that was the crosswind at the time.

But when I went the other direction on the same road with the same wind
the bike still wanted to veer to the right.
Well maybe it's the bag I'm wearing, or the way my bum leg is acting up
today or something.

But no, the bike definitely wanted to be veering to the right, enough
so that I discovered if I leaned waaaay over to the left I could kind
of sort of go handsfree for a real short while.

That was yesterday.

After finishing the usual evening on the beach road I went to the shop
and they fussed it about a bit, making it a whole lot better but still
not good enough for going handsfree. The little bike shop fussed
around a bit more when I came over to get the bag I'd left there before
going riding and made it still better but not like before.

So, I was back at the big bike shop again this evening, late enough
that the wrench was non-busy enough to be able to really look at it.
His verdict is that maybe I did something to the handlebars when I
crashed or perhaps the (best I can tell he was referring to the
headset) and if I replace those that might fix it, or not, cause there
is always a chance that I actually did something to the frame.

Now I like the wrench. He was my Chinese little brother long before
the joke that the bike shop owner was my Chinese mom became the reality
of her growling at me to do my homework and inviting me over to dinner
at her house 2-3 times a week. I was teaching him useful English
phrases like "why did the chicken cross the road" before I knew useful
Chinese words like "pedal," or "spoke."

Whether or not I like the wrench there is a lot of stuff that we don't
see eye to eye on (and not just because I'm a lot taller than him).
Putting a single new tire on the front and putting the old front on the
rear, or only replacing the chain instead of replacing chain and gears
at the same time would be a few examples. (Writing about this leads me
to realize that I should probably be going over to the little shop and
measuring the chain for wear to find out if it needs replacing.)

Besides which, no matter how much I like him, there's something about
him that, when it comes to paying money to replace something, I
instinctively don't trust him. Especially when it comes to buying
something expensive. I can be his friend and at the same time when
repairwork comes down to taking out my wallet there is something that
makes me stop and, at a minimum, get an opinion from at least one of
his coworkers and maybe from the competition as well as asking on here.


Obviously _something_ is wrong with my bike. I used to be able to ride
kilometers at a time handsfree and even do stupid stuff like stand up
on the pedals and coast to a near stop handsfree. I can still do this
on other bikes so the problem isn't a physical one or a psychological
one. Since steering when riding handsfree is done entirely by shifting
weight I can compensate for the veer by leaning way to the left but
this isn't a solution and the fact that I need to do that when
attempting to ride handsfree could mean that I'm automatically
compensating for steering problems when riding with my hands.

If the problem is in the handlebars (which I was thinking of replacing
with something more ergonomic anyways) how could it be detected? I
don't particularly like the suggestion that I buy a new set, and test
ride them, and if the problem goes away then that is where the problem
was.

If the problem is in the headset (best I can tell that's what he was
talking about, it's one of those words that isn't in my Chinese lexicon
and isn't in my Chinese/English dictionary) how could it best be
detected? Again, I'm not real thrilled with the suggestion of
replacement as a method of detection.

If the problem is my frame or fork oughtn't I expect there to be some
cosmetic damage or could I have managed to mung it up sufficiently
enough to mess up the balance without scuffing the paint or decals?

Since the front rim was replaced, and the new handbuilt front wheel
(using old spokes and hub) seems to be nice and true, is it safe to say
that the problem is not the wheel? Could such a problem be the wheel?

Thanks,
-M

I think your question is: "After a front-end impact, my bike pulls to
the right - what gives?"

If that is your question, the answer is: "Have your fork alignment
checked by a good shop."

-Vee

Marian wrote:
But no, the bike definitely wanted to be veering to the right, enough
so that I discovered if I leaned waaaay over to the left I could kind
of sort of go handsfree for a real short while.

http://www.sheldonbrown.com/brandt/pull-side.html

Jan

On 25 May 2006 08:58:36 -0700, "Marian"
wrote:

I crashed my bike about three weeks ago. As these things go it could
have been a lot more serious than it was but I wasn't going
particularly fast (22-23kph) and I had at least a few seconds warning
before I hit the idiot who was riding diagonally against traffic.

My front rim was bent beyond any thought of repair, the sidewall of my
rear tire had a number of small tears, and my helmet needed replacing.

I can't say I particularly noticed any difference in ride quality after
the crash. However, a few days ago when I was out on a borrowed
mountain bike I was riding handsfree and it suddenly occured to me that
I hadn't gone handsfree since the crash.

So, I tried it on my bike. And I couldn't. The bike kept wanting to
veer to the right.

That may be a sign of a bent fork or a bent frame.

If the problem is in the handlebars (which I was thinking of replacing
with something more ergonomic anyways) how could it be detected?

It's not in the bars. Once your hands are off of them, they have no
effect on steering unless something else is grabbing them and applying
force. I've seen a much-too-short brake cable cause that effect but
somehow I doubt that this is your problem.

I
don't particularly like the suggestion that I buy a new set, and test
ride them, and if the problem goes away then that is where the problem
was.

Nor do I.

If the problem is in the headset (best I can tell that's what he was
talking about, it's one of those words that isn't in my Chinese lexicon
and isn't in my Chinese/English dictionary) how could it best be
detected? Again, I'm not real thrilled with the suggestion of
replacement as a method of detection.

Once again, i don't think this is the source of the problem. A bent
steer tube could do it, but if there's no play in the headset, I think
the problem must lie elsewhere.

If the problem is my frame or fork oughtn't I expect there to be some
cosmetic damage or could I have managed to mung it up sufficiently
enough to mess up the balance without scuffing the paint or decals?

Usually, a bent frame will manifest itself via kinks in the tubes; in
a frontal collision, I'd expect that to show up in the downtube just
below the head tube, on the underside. It's much more likely that the
fork is bent, though.Have someone hold the bike upright, and see if
both wheels are in the same plane; looking from directly in front or
directly from the rear, it is sometimes possible to spot a bent fork
this way...but not always. Also, if you snap a chalk line 10m long
(or more) on level pavement, put both tires on it to start, and roll
the bike along it held vertical, if there is something bent, the rear
wheel will track to one side of the line. Others will have better
suggestions about how to spot this problem.

Since the front rim was replaced, and the new handbuilt front wheel
(using old spokes and hub) seems to be nice and true, is it safe to say
that the problem is not the wheel? Could such a problem be the wheel?

The wheel could only contribute by being significantly dished, and
that would be immediately apparent.
--
Typoes are a feature, not a bug.
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Words processed in a facility that contains nuts.

"Marian" wrote:

Is the chalk line a bent frame test, a bent fork test, or both?

The easiest frame alignment test is to run a string from the outside
of the dropout (ideally, through the point the axle sits in), up
around the head tube, and back to the other side of the dropout.

Then measure the distance from the seat tube to the string on both
sides. It should be within a mm or so of the same distance on both
sides. If it's much more than that, it'll affect the handling of the
bike.

Keep in mind this isn't an all-inclusive test of all the frame
dimensions, but will normally indicate if a crash has seriously
tweaked a frame (since it measures the deflection that's most likely
to occur in a typical crash).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame