Author Topic: In a tight spot ! (Read 878 times)

BENDYCAT ELEVENTEEN · « **on:** June 25, 2011, 02:14 PM »

right have just fitted a new freewheel - quick change over and only took two hour

had to dremel grinder cut the old one off as it wouldn't shift and had a bad way to lock on tool to get off

i beat the fooker

so put the back wheel on again and still had a tight spot on the chain

I have come to the conclusion of why you get a tight spot in the chain

two parts : 1st when lining up a back wheel we always look at the tire to see if it spin straight - tire is not always made true / throwing it out a bit - axle side may not be equal in drop outs on each side - but i think that the thing that throws it out most is the chain ring !

the chain ring may be flat and round but when putting it on a 1pc it is at a slight % out when spinning it without a chain on - it may be less them 1-2mm wobble when turning and this may not seem much, but it will make a difference

freewheel may have a wobble in it - can be more with cheap FW

so if a chain ring spins round it could be the ring is not at it's centre point and /or the one piece crank is not spinning true - if looking down on the chain ring and seeing it turn then you may see the wobble, and with a chain on and the freewheel also moving with a wobble it can all throw it out

this is what i think that a tight spot is on a bike chain - any thoughts please welcome

cheers B

oldschoolace · « **Reply #1 on:** June 25, 2011, 02:27 PM »

As far as i have always experienced, singular tight spots (where the chain tightens at one particular spot over and over) is always down to either a stiff link on the chain or a slightly off centered chainring. I cant see how it would be wheel alignment as this should produce a constant bind rather than an intermittent one and unless the freewheel is knackered you should be able to rule that out as the cause too.

SteveG · « **Reply #2 on:** June 25, 2011, 05:28 PM »

Prime suspect for me is the spider on the crank, depends what you have though. One piece cranks aren't very well made and could have a bend in them between the crank bearings.
I haven't tried it but if you loosen the bit that locks the spider on you might be able to tap it one direction to make it run true. Then tighten it carefully again.
Have a similar problem on my old kart. The problem with that is that the axle is a bit bent though !

AKGOFF · « **Reply #3 on:** June 25, 2011, 07:28 PM »

As everyone knows I,m the king of bike building Bendy so i'll give you a few pointers tomorrow

Adam

Pooch · « **Reply #4 on:** June 25, 2011, 10:54 PM »

1/ tight link on chain.
2/ chain ring not centre on the spider.
3/ had to put my chain ring on the inside of my power disc on the gt for it to run true..
4/ Don't ask Adam anything as he doesn't know his arse from his elbow..