Is my bike worth fixing? Will it be easy?

[peanut]

Mickle you have PM.

Thanks Peanut, but I reckon Dave has got a fair point.

Jon.

blimey I stick up for ya and you kick me in the teeth for it

If you are one of life's 'real engineers' you'll learn as you go and you'll want to take everything to bits to see how it works, how its failed and if the original design can be improved upon when you rebuild it .
I've not found anything yet that I haven't been able to fix

 

[jon the student]

Ha ha, sorry peanut! I should probably stop being lazy then and get on with it. Cars seem like big lego kits to me, so I don't see why bikes should be any different - maybe i just need to learn the particulars.

I'll get some proper pics of the beast up tomorrow.

 

[Dave5N]

blimey I stick up for ya and you kick me in the teeth for it

If you are one of life's 'real engineers' you'll learn as you go and you'll want to take everything to bits to see how it works, how its failed and if the original design can be improved upon when you rebuild it .
I've not found anything yet that I haven't been able to fix

Who's being grumpy now? And wasn't that my point yesterday anyway?

 

[jon the student]

ooooh, fight.... meaaoouwww...

 

[Dave5N]

No. Just me taking the pish...

 

[jon the student]

ha ha fair enough.

I was also wondering if there is somewhere I can check what height the bars and seat should be for me? I'm under the assumption that the seat should be adjusted so that my leg is fully straight and foot flat on the pedal in the lowest crank position (i'm on tip toes when I put my foot on the road when stopped), but I haven't been able to move my bars cos I think you need spacers to raise the bar up a bit.

 

[peanut]

if sprockets are cogs then I have 7, it's a 21-speed. but the crank slip / chain bounce happens a lot on the bottom and middle 7 (i.e. small and medium chain wheels) so I leave it in the top 7. This kinda proved my theory that the chain is stretched as the top 7 gears is obviously largest chainwheel so it takes up more of the chain slack if that makes sense.

no it probably means your either a chain link is tight or the rear mech tension spring which keeps the chain tight is weak and worn out as I said in an earlier post.If your transmission is as old as you say it is probably best to replace it and don't waste any more time on it.
The spring in the rear mech maintains chain tension throughout the range of gears ie from big chain ring and biggest sprocket to small chainring and smallest sprocket combinations. It has a lot of work to do when on the small/small combo

 

[jon the student]

So the sprockets are the smaller cogs on the gear mech? there are 2 in that case, and they tend to jam if i pack pedal the bike when stationary (i.e. chain kinda tries to pinch itself together in the middle if that makes sense and eventually jumps across the cassette at the back). That's also happened once at speed, but i just pulled over and treated it as if my chain had come off.

 

[oxbob]

this might help?

 

[jon the student]

thanks oxbob, I was thinking about the jockey wheels.

Wow: cassettes, jockeys, chainwheels, sprockets. I have learned a lot today.

 

[peanut]

engineer ? engineer my ass ! you can't even use the google search facility look for sprocket and to find a detailed picture of bicycle bits ? come on give me a break

 

[Dave5N]

Calm down, man.

JTS - your symptoms are common to worn chains and cassettes.

Get new ones. Fit them. If you still have problems, ask again.

 

[jon the student]

Ace, thanks for the continued help.

Peanut, sorry for the emotional turmoil. Will a twix cheer you up?

 

[swee'pea99]

Two sites definitely worth checking out if you're contemplating diy:

http://bicycletutor.com/

and

http://www.parktool.com/

 

[jon the student]

Thanks swee'pea, I'll definitely check those out.

Better get to bed as I've got an electronics (witchcraft) exam tomorrow.