# Chain just coming off



## Joe24 (18 Jan 2009)

On the fixed today, my chain came off twice, before i left the group and limped home.
The first time i could sort of understand. I was going down a steep-ish hill, spinning fast that was a tad bumpy, so im guessing on a slack spot the chain came off. It was ok, came off front and back and my back wheel didnt lock up.
Second time, just gone over the top of a rise, on the way down the other side coming up to a RAB the chain just jumped off again. It was on tight enough so it wasnt that, and the chainring is not bent.
So i have no idea why it came off. The fixed is now lighter, and looks like this.





Im getting a new fixed frame soon, and putting some of the stuff from this fixed onto the new frame, with some new nice parts
Then the old fixed frame will be turned into a TT bike when i have enough money.

What makes my chain jump off? Was i lucky that it didnt catch?


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## spandex (18 Jan 2009)

It is good to know that you are ok

Why 
chain line
slack chain


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## peejay78 (18 Jan 2009)

what he said. ^


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## Joe24 (18 Jan 2009)

spandex said:


> It is good to know that you are ok
> 
> Why
> chain line
> slack chain



Chain not that slack. It does go tight/slack but in the slack bit it wasnt that slack. Its been slacker
Cant do much more on chainline, cranks over as far and chainring on other side of the spider.
What are the chances for the back wheel to lock up? Is it a larger chance or just 50/50?


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## peanut (18 Jan 2009)

were you in or out of the saddle at the time ? just thinking it must be due to misalignment between the front chainring and the rear sprocket. Have you checked from the rear? maybe put the bike on a stand and turn pedals backwards as well as forwards and see how true the chain runs


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## Joe24 (18 Jan 2009)

peanut said:


> were you in or out of the saddle at the time ? just thinking it must be due to misalignment between the front chainring and the rear sprocket. Have you checked from the rear? maybe put the bike on a stand and turn pedals backwards as well as forwards and see how true the chain runs



Sitting down both times.
Cant put it on now, everything is off it.
Just seemed strange that it just popped off, even after i had put more tension on the chain.


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## spandex (18 Jan 2009)

It is the chain line mate going by what you have said. The only way to move it over is to get a shorter BB.


You asked what is the % of the back wheel locking if the chain came off? Now one can say for sure but it will be Hi I would of thought?


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## spandex (18 Jan 2009)

And just remember what happened to me when I came of my fixed at speed.......


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## Joe24 (18 Jan 2009)

spandex said:


> And just remember what happened to me when I came of my fixed at speed.......



I do, it was very scary when the chain came off the first time, i was doing about 30mph


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## Dave5N (18 Jan 2009)

Is the chain or transmission worn?


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## Joe24 (18 Jan 2009)

Dave5N said:


> Is the chain or transmission worn?



Chain was new just before xmas. Chainring new jus before xmas. Sprocket is an old one, it isnt worn though.


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## spandex (18 Jan 2009)

Joe24 said:


> *Chain was new just before xmas*. Chainring new jus before xmas. Sprocket is an old one, it isnt worn though.




My chain was new 8months ago and it has done say 1500miles KMC Z610HX  with a tensile strength of 1,500 Kg  and mine is dead that is I need a new one now dead.


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## peanut (18 Jan 2009)

Joe24 said:


> Sitting down both times.
> Cant put it on now, everything is off it.
> Just seemed strange that it just popped off, even after i had put more tension on the chain.



It could have been due to the bottom bracket moving sideways under pedalling pressure . Old steel frames deflect a lot around the BB especially if they are big frames like yours


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## Joe24 (18 Jan 2009)

My 1/8th has only done about400/500miles since it was put on. Not done much.
I am getting a new one for when the proper fixed is built up though.
The other 1/8th chain i did about 1500miles on hadnt worn much, but i had twisted 2 links in it so had to get a new one. Thats the power for you


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## Joe24 (18 Jan 2009)

peanut said:


> It could have been due to the bottom bracket moving sideways under pedalling pressure . Old steel frames deflect a lot around the BB especially if they are big frames like yours



Does that mean that the bottom bracket moves from side to side?
If so, thats what ive been told as to why the chainring collapsed, but was said the frame flexed, now that the BB was deflecting.


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## spandex (18 Jan 2009)

BB's do not deflect


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## Joe24 (18 Jan 2009)

spandex said:


> BB's do not deflect



Deflect means move, right?


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## spandex (18 Jan 2009)

Yes

they do not move side to side!


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## rustychisel (20 Jan 2009)

Chains don't JUST come off, in my experience. It may be the lateral movement in the frame is allowing it to be pushed off the chainring, but a not round chainring is likely allowing it to be lifted and dropped at the same time. 

Bottom Brackets don't move sideways, but the flex in an (old steel) frame, for example, is perfectly capable of allowing the drivetrain to move laterally by ~5mm.


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## peanut (20 Jan 2009)

Joe24 said:


> Does that mean that the bottom bracket moves from side to side?
> If so, thats what ive been told as to why the chainring collapsed, but was said the frame flexed, now that the BB was deflecting.



no the bottom bracket doesn't deflect does it !....it is the bicycle frame that deflects. The bottom bracket goes with the frame . As the frame deflects the bottom bracket and chainset go out of verticle alignment which ships the chain. Rusty chisel has put it much more elequently than I


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## skwerl (20 Jan 2009)

peanut said:


> no the bottom bracket doesn't deflect does it !....it is the bicycle frame that deflects. The bottom bracket goes with the frame . As the frame deflects the bottom bracket and chainset go out of verticle alignment which ships the chain. Rusty chisel has put it much more elequently than I



only under heavy load though. ie when out of saddle going uphill. Joe was heading downhill at the time, I think, so can't see there being enough pressure on the frame to twist it enough.

I think the chain was too slack. When your're pedalling at that rate there's enough momentum to pull cthe chain off if only a bit of it starts to unship


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## Andy Pandy (20 Jan 2009)

I had a similar problem that was due to the front chainring. It wasn't very round, giving tight and slack spots on the chain. As it was off a geared bike it had a small section where the teeth were smaller (to allow the chain to move off the chainring). Going down hills when there was little load on the chain, and you hit a bump in the road (when the chain was slack) it could simply bounce off the ring.


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## peanut (20 Jan 2009)

skwerl said:


> only under heavy load though. so can't see there being enough pressure on the frame to twist it enough.



the pressure is caused by it being a fixed gear bike isn't it  if it was a freewheel there would be none but a fixed is in constant connection with your body through the pedals whether pushing to accelerate or pulling to de-accelerate when going downhill .


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## itboffin (28 Jan 2009)

My chain popped off 2 miles from home on a rapid downhill, further inspection revealed a slack chain and I know the tension was just right when i set out, I don't think for one minute that I'm a powerful or even strong rider but is it possible that the axle or nut are worn? 

It was a long ride with lots of hills many of which I had to really stomp to get over.

Both the chain & freewheel are new.


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## MrGrumpy (29 Jan 2009)

I was advised to buy these and then not worry at all about tension 

http://www.tartybikes.co.uk/product.php?product_id=170&category_id=8


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## itboffin (29 Jan 2009)

I've seen those but how do they work? it's not obvious from the image.


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## Landslide (29 Jan 2009)

Round bit goes over your axle (twixt either frame and locknuts or frame and wheelnuts), squarish bit sits over the ends of your dropouts. Tighten the nut and it pulls the wheel back in the dropouts. NB: This is only applicable for rear-facing track dropouts.

I reckon Joe's problem is just his sheer power. I bow before your thighs, Oh Mighty One!
(This post may contain traces of sarcasm )


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## Joe24 (29 Jan 2009)

Landslide said:


> Round bit goes over your axle (twixt either frame and locknuts or frame and wheelnuts), squarish bit sits over the ends of your dropouts. Tighten the nut and it pulls the wheel back in the dropouts. NB: This is only applicable for rear-facing track dropouts.
> 
> *I reckon Joe's problem is just his sheer power. I bow before your thighs, Oh Mighty One*!
> (This post may contain traces of sarcasm )



I was in the gym today and did 40 reps of 150kg's on the leg press. Only another 40kg untill im doing the full stack of weights on that machine(only goes up to 190kg)
Mines is infact my sheer force in the legs
Im trying to decide whether to get a new frame(comes with carbon forks, and ill be getting headset, crankset, chain, stem handlebars, seatpin, bar tape) or to get a 2008 Giant Bowery.
The Giant Bowey is £110 cheaper, but the frame looks abit nicer and its got carbon forks.
It really is a hard decision to make


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## skwerl (29 Jan 2009)

peanut said:


> the pressure is caused by it being a fixed gear bike isn't it  if it was a freewheel there would be none but a fixed is in constant connection with your body through the pedals whether pushing to accelerate or pulling to de-accelerate when going downhill .



Not realluy.
Being fixed is largely irrelevant. You may be in constant connection but for a fair bit of the pedal stroke you're coasting. You still put most pressure through the first half of the stroke (about 2 o'clock to 6 o'clock). You can't put enough backwards pressure on (esp. when going fast) to twist the frame. the only time you'll see flexing is when you give it the BDC grunt


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## itboffin (29 Jan 2009)

Joe24 said:


> I was in the gym today and did 40 reps of 150kg's on the leg press. Only another 40kg untill im doing the full stack of weights on that machine(only goes up to 190kg)
> Mines is infact my sheer force in the legs
> Im trying to decide whether to get a new frame(comes with carbon forks, and ill be getting headset, crankset, chain, stem handlebars, seatpin, bar tape) or to get a 2008 Giant Bowery.
> The Giant Bowey is £110 cheaper, but the frame looks abit nicer and its got carbon forks.
> It really is a hard decision to make



well mine is because I'm old & too weak to tighten the nuts enough 

40 reps of 150kg - PHEW! you sir are mental, in the nicest possible way


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## bonj2 (29 Jan 2009)

Joe24 said:


> I was in the gym today and did 40 reps of 150kg's on the leg press. Only another 40kg untill im doing the full stack of weights on that machine(only goes up to 190kg)
> Mines is infact my sheer force in the legs
> Im trying to decide whether to *get a new frame(comes with carbon forks*, and ill be getting headset, crankset, chain, stem handlebars, seatpin, bar tape) or to get a 2008 Giant Bowery.
> The Giant Bowey is £110 cheaper, but the frame looks abit nicer and its got carbon forks.
> It really is a hard decision to make



what frame/forks


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## bonj2 (29 Jan 2009)

itboffin said:


> well mine is because I'm old & too weak to tighten the nuts enough
> 
> 40 reps of 150kg - PHEW! you sir are mental, in the nicest possible way



he means that one where you lie on your back with your shins raised and the flats of your feet against the pusher. right joe?
still 150kgs quite a lot especially for 40 reps


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## Joe24 (29 Jan 2009)

itboffin said:


> well mine is because I'm old & too weak to tighten the nuts enough
> 
> 40 reps of 150kg - PHEW! you sir are mental, in the nicest possible way



It was 10 reps, then 20 reps, then 10 reps, not 40 all in one go. So doesnt sound as good when put like that, but there wasnt much of a break between them. Didnt think it was bad to say i have only just started going and im 17.
Yep, you got the right machine, lieing back, and you push against a board and the seat moves.
The frame/forks are from Langdale Lightweights. Ive decided on this one, its their 'own' frame, can take full mudguards and a rack if i wanted aswell.


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## Radius (29 Jan 2009)

C'mon now Joe that's the easiest machine


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## Joe24 (29 Jan 2009)

Radius said:


> C'mon now Joe that's the easiest machine




So what weight do you do then
I go on all the leg ones, except the ones where you open/close your legs, and the one where you lie flat on the thingy.
But, from you saying its the easiest and not putting a weight/saying you can do more i take it you cant


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## Radius (29 Jan 2009)

You fell into that one. I would like to point out how you immediately assume I can't do anything in terms of weight (or at least that's how your post comes across). I also won't engage in 'manly man' arguments, cos I'm fast enough and will get faster (and am even faster at sprinting not on a bike), fit enough and will get fitter.


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## Joe24 (29 Jan 2009)

Radius said:


> You fell into that one. I would like to point out how you immediately assume I can't do anything in terms of weioht (or at least that's how your post comes across). I also won't engage in 'manly man' arguments, cos I'm fast enough and will get faster (and am even faster at sprinting not on a bike), fit enough and will get fitter.



So basicly, you cant do more then me, even on the easiest machine?
Im also getting faster, fitter and stronger. So where abouts is what your saying?
Come on, tell us what you can push on it


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## Radius (29 Jan 2009)

Did I say I couldn't? There's no point in exchanging stats cos for all I know you could be lying, and vice versa. You're not god, did you know that?


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## bonj2 (29 Jan 2009)

Joe24 said:


> The frame/forks are from Langdale Lightweights. Ive decided on this one, its their 'own' frame, can take full mudguards and a rack if i wanted aswell.



yeah get that
steel or alloy?
it's going to be fairly individual at least, can't see there being many of them around. probably loads of bowerys


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## Joe24 (29 Jan 2009)

Radius said:


> Did I say I couldn't? There's no point in exchanging stats cos for all I know you could be lying, and vice versa. You're not god, did you know that?



Ill wack my phone out next time and film me doing it then, that can give you some time to go and try your hardest to push that
Just admit you can only push 40kg


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## Joe24 (29 Jan 2009)

_Ben_ said:


> yeah get that
> steel or alloy?
> it's going to be fairly individual at least, can't see there being many of them around. probably loads of bowerys



My thoughts are this. The fixed(well now just a frame, but the old fixed) was original with the parts.
Plus i get some carbon with the Langdale frame
Its alloy with carbon forks.


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## bonj2 (29 Jan 2009)

what can you do on the hamstring puller, the one where you sit with the resting position is your legs outstretched, and the crunch is to bring your feet down and in


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## Joe24 (29 Jan 2009)

_Ben_ said:


> what can you do on the hamstring puller, the one where you sit with the resting position is your legs outstretched, and the crunch is to bring your feet down and in



40/50kg on that, and do it 20 reps at a time. Problem i have is keeping my arse on the seat I have both hands on the handle and im pulling down hard and i can sort of feel myself moving up. Am i doing something wrong or is it me being light? I think thats on the other one that you mean though, the one where you pull them up?
When we got shown around we went on that pull up one, which has the counter weight there. The guy weighed 80kg and put 60kg on. Everyone else in the group went on and it moved down, i went on and it hardly moved. I only weigh 63kgs


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## bonj2 (29 Jan 2009)

Joe24 said:


> 40/50kg on that, and do it 20 reps at a time. Problem i have is keeping my arse on the seat I have both hands on the handle and im pulling down hard and i can sort of feel myself moving up. Am i doing something wrong or is it me being light? I think thats on the other one that you mean though, the one where you pull them up?
> When we got shown around we went on that pull up one, which has the counter weight there. The guy weighed 80kg and put 60kg on. Everyone else in the group went on and it moved down, i went on and it hardly moved. I only weigh 63kgs



50kg for 20 reps is quite hardcore.
i used to do 55 but only 10 reps. 20 reps at 40/45 ish. 

don't know - pull down on the handle but maybe try and 'scoop' it? - let yourself rise up a bit but then give a massive pull on it. i don't know really, have to say i don't ever go to the gym nowadays i find it deathly boring.
I only ever really used to go to justify going in the steam room/sauna...


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## Joe24 (29 Jan 2009)

Ah, not tried scooping. I pull on the handles hard, and it keeps me down, but i do have to pull hard.
I go in my free lessons when i have time, which is good because i would normally just be sat around in a common room or sat at home.
Not sure how long its going to last though. And whats funny is the amount of people with gym membership(mostly girls) in 6th form that dont go.


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## threebikesmcginty (31 Jan 2009)

Are you two gonna get married?


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## Joe24 (31 Jan 2009)

threebikesmcginty said:


> Are you two gonna get married?



No, why? You offering? Sorry ive got a GF and im not gay


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