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Conference noted::bicycle

Title: Bicycling
Notice:Bicycling for Fun
Moderator:JAMIN::WASSER
Created:Mon Apr 14 1986
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3214
Total number of notes:31946

771.0. "Need mechanical help - fast" by NECVAX::SCHOTT_R () Wed Jul 13 1988 13:30

         I'm hoping that some of you whiz-bang bike mechanics can 
    give me some quick advice regarding a mechanical problem I'm having
    with my rear derailleur.  I own a Peugeot 501 bicycle that's equipped
    with Huret derailleurs.  The Huret equipment is probably their low-end
    to mid-range stuff, as the bike was in the $350-400 price range when new.
    
         The problem is this.  When I stand in the pedals in a low to
    mid range gear to power up a hill, the rear derailleur jumps to
    the next higher gear.  This jump or skip is very disconcerting
    when it happens, and I'm sure its doing the bike's power train
    absolutely no good.  It only happens when I'm standing, and only 
    when I'm applying my maximum power.
    
         I have the bike tuned up at the beginning of each season,
    (it's now three years old), but I usually shy away from in season
    repairs, in that I'm not that mechanically inclined.
    
         I'm entered in a triathlon this weekend, and I need to be able
    to work on the hills, so whatever advice you all can give would
    be very much appreciated.
    
    Russ
    
T.RTitleUserPersonal
Name
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771.1REALLY basic troubleshootingCIMNET::MJOHNSONAble to leap protocol towers in a single boundWed Jul 13 1988 13:399
    This suggestion is so basic, I hesitate to make it, but....
    How tight are your shift levers?  Could it be that they're
    just too loose?
    
    Other things to check for are the aligment of the derailleur
    (has the bike been laid on its side recently?), and wear of
    the chain and cogs.
    
    MATT
771.2Flex?CCYLON::SCHULDTLarry Schuldt - WA9TAHWed Jul 13 1988 13:573
    I read in the magazines that this is a common symptom of frame flex.
    At any rate the circumstances are right.  I wouldn't know for sure,
    cuz I certainly don't have that kind of power.....
771.3A QUICK FIXLILAC::MARCINKUSWed Jul 13 1988 14:096
    Russ - Your problem is most likely what Matt pointed out.  Tighten
           down on the freewheel shift lever screw and that should do
           it.  It may seem already tight enough but give it a little
           more and try it out.  Good luck with the triathlon.
    
                                    John
771.4NECVAX::SCHOTT_RWed Jul 13 1988 14:1216
         Thanks for your thoughts, Matt and Larry.  I have checked the
    tension on my shift levers (I know I said I was mechanically
    disinclined, but I'm not quite that ......).  I also am
    very careful regarding the derailleur side of the bike and have
    never crashed (knock on wood), and they seem to be shifting
    nicely otherwise.  As for frame flex, I've noticed that this 
    particular frame, which is made from Reynolds 501 tubing, is not
    as stiff as the frame on the Centurion I was previously riding,
    but I doubt if I could apply enough force to cause this particular
    problem.
    
         I guess wear and tear on the crank, cogs and chain could be
    a possibility.  What in particular should I look for?
    
    Russ 
                            
771.5Was frame flex for us!PRYDE::DAMICOJANE DAMICOWed Jul 13 1988 14:1314
    Well, I don't exactly know what the terminology for the problem
    is, but my boyfriend had the exact same trouble with his Cannondale
    SR500 after only owning it for about 3 weeks.  I believe the person
    in .2 described it as frame flex.  I think that was his trouble,
    because, when we took it back to O'Neils to be looked at, while
    they were working on it, the frame split somewhere near the back
    wheel.  To make a long story short, he had the frame replaced, and
    not a problem since.
    
    By the way, does anyone have any comments about standing to do hills?
     I try and stay in the saddle the entire ride even up steep hills,
    which kills my quads during training rides, however, I tend to also
    do that during races just out of routine.  Is there any rule of
    thumb around how to get up hills the most efficient way?
771.6STEP BY STEP ANALYSISAKOV11::FULLERWed Jul 13 1988 14:2824
    Things to analyze in order:
    
    1.  Loose shift lever  Solution: tighten with finger or screwdriver
    
    2.  Tight link in chain  Solution:  Carefully backpedal chain to
    see if there is one link that stays bent. Use chain tool or place
    chain between hands and flex chain sideways to loosen chain.
    
    3. Worn chain  solution: replace chain
    
    4. Worn freewheel cogs:  If you have changed the chain, this could
    certainly be the problem.  Solution: New freewheel or cogs, change
    chain at same time if it is old
    
    5. Derailleur tightened onto hanger to tightly.  Derailleur should
    move freely on dropout.  Solution:  Loosen slightly, if this solves
    the problem, you may need some bushings or use locktight so derailleur
    won't tighten.
    
    6. Frame damage, look for damage, if there is no damage and the
    bike is not an ultra-long wheebase, I doubt this is the cause.
    

    steve
771.7loose cable?IAMOK::WESTERWed Jul 13 1988 14:598
    If I understand your the problem correctly I think it's just a loose
    derailleur cable.  I had the exact same problem a year ago and the
    mechanic just readjusted the cable.  I'm not exactly sure how to
    do this, but I think it can be accomplished by tightening the cable
    at the shift lever.  Unfortunately, as you've discovered, it throws
    you into a bigger gear instead of a smaller one.  Makes hillclimbing
    even more fun!
    
771.8Hill ClimbingWITNES::MACONEWed Jul 13 1988 15:5531
    Re: -2 or -3, whichever posed the question
    
    Reprinted from Bicycling magazine (WITHOUT PERMISSION) FItness Q&A
    
    Q:  I'm a 50 year old woman who rides for fun and exercise.  When
    climbing, I get off the saddle and pedal in a high gear.  I'v noticed
    other riders spin uphill in a low gear.  which way is best?
    
    A:  You pose an excellent question.  Unfortunately, the answer is
    not yet known.  In fact, I'm currently researching this subject.
     While it's too early to discuss preliminary findings, I cancomment
    on the nature of the problem.
    
    	The key question is whether standing on the pedals affords any
    mechanical advantage in generating force.  I don't know yet, although
    I hope to find out.  I do know that conquering hills in a high gear
    often develops at least one part of a cyclist:  the ego.  Having
    a small freewheel is often considered a measure of a rider's ability
    and strength. For this superficial reason, many cyclists prefer
    to stand whil climbing.   For some individuals this works fine.
     For others, though, a steady spin is the answer
    
    	To discover what's right for you, try climbing the same hill
    several times.  Use a different gear wach time, but always ride
    at the same speed.  Then ask yourslef these questions:  Which gear
    seemed easiset?  Which one produced the lowest (most efficient)heart
    rate?  Did pushing the higher gears hurt my knees?
    
    	The answers will determine what's best for you personal climbing
    style.
    			David P. Swain, Ph.D.
771.9Indexing as a last resortRDGENG::MACFADYENRoderick MacFadyenWed Jul 13 1988 16:4123
    Re .0: 
    
    I had a similar problem back in the stone-age days when I used friction
    shifting (ie a few months ago). It was one of the reasons I went over
    to indexed shifting, since when it hasn't happened at all. I put this
    down to more accurate and consistent placing of the rear derailleur
    relative to the gear sprockets, but maybe it's just because of using a
    nice new block, derailleur and shifters. The advice given here seems
    good; you'd definitely want to explore the cheap options before
    the expensive ones!
    
        
.8>    	The key question is whether standing on the pedals affords any
.8>    mechanical advantage in generating force.  I don't know yet, although
.8>    I hope to find out.
    
    This isn't a difficult question! There's more force available when
    you stand, and that's a fact. The trouble is that it tires you out
    quicker, and that's why the choice of sitting/standing can be tricky.
    But if you've come to a steeper hill than your bottom gear is intended
    for, you just have to stand if you want to get up it.
    
    Rod
771.10.6 and .7 are correctVMSNET::HOOD_DOWed Jul 13 1988 17:0911
    I have had the change-gear-under-torque problem under two conditions:
    1) a tight or jammed chain link
    2) improperly adjusted derailler cable
    
    replies .6 and .7 are correct.
    derailler cable tension should be taken up at the derailler, save
    any tension adjustment at the shifter for on the road adjustments.
    the same is true of brakes. if the brake cable needs adjusting,
    adjust at the brake and save the adjustment at the lever for when
    you have less tools and hands to work with (like on the road).
    
771.11Gear Lever Screw ?DUB01::OSULLIVANWed Jul 13 1988 17:267
    I once had a similar problem to the one you described .
    It turned out that the screw through the centre of the gear lever
    was fractionally too long so that when it felt tight as could be
    , it was really only bearing against the frame. I insertes a small
    washer and this did the trick.  Worth a try.
    
    John 
771.12frame flex...JETSAM::DRISCOLLWed Jul 13 1988 22:087
     The same problem is happening to my FRONT deraileur, when I'm going
    up a hill and applying force, the the front deraileur will slowly
    move until the chain drops to the next chainring... I believe it's
    caused by frame flex. I've tightened the shifter screw to no avail
    and simply shift to the lower chainring before climbing a hill.
    
     Tim
771.13more opinionBANZAI::FISHERKeep 'em rollin'Thu Jul 14 1988 10:5721
I've had this problem for years, even crashed dreadfully when the chain
ended up freewheeling (riding on top of the gears).

If you're a perfect shifter and this is never a problem, <next note>.

The frame flexes a bit on hills especially when you're out of the saddle.
That tugs the rear derailleur a bit and I have one bike where I know
that even the front derailleur gets tugged.  One more thing to try without
going to clickers:  Before getting out of the saddle downshift about
1/8 to 1/4 of a shift, i.e., not enough to shift and not enough to get clickety
noises from the chain but enough to assure that the chain is on the
low side of the freewheel cog, then the tugs on the rear derailleur
won't shift it.

As for "stand" vs "sit," I think you must find out what works for you.
BUt you should work on "stand" occassionally to see if there is anythin
to improve in your technique.  I find that I can stand for longer peiods
of time as I get my weight down.  I don't just mean stand on the pedals
passively either, you must be forcing them down by pulling up on the
bars.  You should be using a gear that about 3 inches higher when you
are out of the saddle -- unless the hill is all you can take anyway.
771.14More Advice neededASIC::CRITCHLOWThu Jul 14 1988 12:3922
I have somewhat related question. My wife has been having trouble 
shifting the rear deraillure lately. The problem occurs when she tries 
to shift out of the smallest gear on the rear hub to either the next 
gear or the middle. 

What happens is this: 

The chain will move over with the deraillure but it won't catch on the 
the bigger gears. It ends up sliding laying diagonally over the smallest 
two or three gears. I know this is not just her because it happens when 
I ride the bike and I never have trouble shifting. You can spin the 
cranks as much as you want when you get into this state and the chain 
refuses to catch. 

It is very frustrating for her since the times she  wants to shift from
the smallest gear to the bigger ones is when she is starting on a hill.


My thought was that she may need another chain. Wider? Narrower? How do I 
tell if this is the case? Does anyone else have any suggestions?

JC
771.15REPLACE YOUR PARTS ON HER BIKEAKOV11::FULLERThu Jul 14 1988 14:5215
Without knowing the make of the bike, derailleur, age etc, its difficult
    to know the actual cause.  If you are mechanically inclined, I
    recommend that you:
    
    1.  Put your rear wheel on her bike and see if it works better.
        This would narrow the problem to the freewheel or perhaps der.
        adjustment
    
    2.  Put your chain on the bike
    
    3.  Put your rear derailleur on the bike.
    
    If you go through these steps, it may end up saving you money.
    
    steve
771.16& BUY ALL NEW ONES FOR YOURSELF!FRAGLE::RICHARDThu Jul 14 1988 18:521