# What chain?



## mcb2080 (8 Jul 2009)

Looking for some help please.

I have a ridgeback nemesis which has an 8 speed hub but I can never get the chain tension right and my chain seems to slip about every 50 / 60 miles

I have had it into the lbs a few times but they can never get the chain to slip so they can't seem to fix the problem.

I enquired about a half link chain but they didn't seem to think that this is a good idea. I like the idea as I reckon this will fix the tension problem. 

I currently have a shimano nx 10 which is a 1/2 x 1/8 inch chain, I have been looking at a charge masher 1/8 chain or a diamond back half link chain but I can't seem to find what the other part of the size is.

Can you use any size of 1/8 chain on a fixed hub or the fact that I currently have a 1/2 chain mean that I will need a similar 1/2 x 1/8 half link chain (if this size exists)

Sorry if the size bits doesn't make sense as I don't know too much about bikes in general.

Thanks

Mark


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## Gerry Attrick (8 Jul 2009)

If the chain is slipping, then either the chain or the cassette or both is/are worn.


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## Bigtwin (8 Jul 2009)

Yes - this doesn't smack of a chain problem - did you change the casette and chain together?


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## mcb2080 (8 Jul 2009)

Gerry Attrick said:


> If the chain is slipping, then either the chain or the cassette or both is/are worn.



Thanks for the reply Gerry, sorry I forgot to add into the above that when I am tighten the back wheel that if I pull the wheel as far away from the pedals, I get the right tension to begin with but then after 50 / 60 miles I think the rear axle slips slightly forward towards the pedal on one side and this makes the chain come off.

What I was wanting to do was push the wheel as close to the pedals then by using a half link chain this should sort out the tension and give the bolt a right good tight and hope this sorts out the tension, I tried pushing the wheel completely forward and took a link out of the normal chain but it was just to small to go on the bike.


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## Gerry Attrick (8 Jul 2009)

The small distance available on horizontle drop outs is unlikely to make any difference. The reason your chain is slipping is as stated above.

Just confirm that you have eight speed derailleiurs. It's not a hub gear is it?


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## mcb2080 (8 Jul 2009)

Where the nuts have been tightened in the past have left grooves into the frame where the non return washers go and I think over time this might be part of the axle slipping, I ordered new washers and have just put them on the bike today with a new kmc chain. I looked at the cassette and it doesn't seem to bad, I think I have done about 800 miles on it.

Again, I put all this to the lbs but as the can't get the chain or axle to slip then they say they can't do much more.


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## mcb2080 (8 Jul 2009)

Gerry Attrick said:


> The small distance available on horizontle drop outs is unlikely to make any difference. The reason your chain is slipping is as stated above.
> 
> Just confirm that you have eight speed derailleiurs. It's not a hub gear is it?



Yeah Gerry, it is an eight speed alfine hub.


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## Bigtwin (8 Jul 2009)

mcb2080 said:


> I looked at the cassette and it doesn't seem to bad, I think I have done about 800 miles on it.




1. Very hard to tell by looking unless you have a new one to compare with.

2. 800 is a far bit for new chain/old sprocket. If you have the hub version, it is a LOT, as of course all those miles are on the same sprocket.


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## Gerry Attrick (8 Jul 2009)

How old is the bike? I have a twenty five year old Dawes which doesn't have chunks out the frame where the rear axle locates.


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## Gerry Attrick (8 Jul 2009)

Ah, so you actually don't have a cassette. Even so, if the chain tension is correct, the only reason it can slip is if the chain and/or rear sprocket is worn. Change both and all should be fine. If you think the axle is slipping forward, you can obtain chain tensioners whch fit to the rear axle/drop outs, but I have no idea whether they are compatible with Alfine hubs.


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## mcb2080 (8 Jul 2009)

I only got the bike last June, yeah there are defo bits out of the frame, I was considering rubbing down all the flaky bits and trying again with re tightening the bolts but as I say I put a new chain and washers on it today.

Would it help if I take some pictures and stick them up here to get an opinion of the wear on the frame and the spocket?

Cheers guys


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## Gerry Attrick (8 Jul 2009)

Pictures can only help.


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## mcb2080 (8 Jul 2009)

The alfine that i have, you can't get chain tensioners for unfortunately.

I have had the chain slipping problem from almost new but as I say the lbs just can't seem to find the problem.

I actually think the lbs is a good shop as they have never charged to look at the problem each time I bring it in.


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## Gerry Attrick (8 Jul 2009)

Just as well if they can't sort it!


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## mcb2080 (8 Jul 2009)

LOL, yeah I hoped that they weren't going to charge either as I may have had something to say as well but I am pretty laid back and don't really like creating a fuss.

I am just uploading pics the now.


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## mcb2080 (8 Jul 2009)

This is the front chain ring just to show any wear and tear



Another pic of front ring



This is the left hand side, the silver that you see is really just the imprints of the grips in the washer but there are defo loads of imprints probably from taking the wheel of so many times to try and fix the tension



Back left again



Right hand side, same again with the imprints



Sprocket to see what you think of wear and tear


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## Gerry Attrick (8 Jul 2009)

One thing, could the "chain slipping" possibly be the internal hub gears slipping? I admit, the sprocket teeth do not seem worn.


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## mcb2080 (8 Jul 2009)

Gerry, the gears always seem fine, probably the only plus point.

Can a gear slip as there isn't a derailer or anything that makes the change move apart from going forward?

On closer inspection a couple of teeth on the front have been flattened at the top of the teeth, i.e no round on them at all and the sprocket has a slight angle of wear and tear to the outer part of it (if that makes sense)

Also I had done about 200 mile before I got a cycle computer so the mileage is closer to 1000 miles.


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## Bigtwin (8 Jul 2009)

Gerry Attrick said:


> One thing, could the "chain slipping" possibly be the internal hub gears slipping? I admit, the sprocket teeth do not seem worn.



I disagree. Follow the curve around and compare the gradient at the LHS to that one the RHS - I think there is a discernible difference to them - that's more than enough to get slip with a new chain. Bottom picture, hold a bendy ruler up to the screen.

Exaggerated example here:


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## Gerry Attrick (8 Jul 2009)

The teeth on the chainset are not cut regularly. This apparently assists in gear changing. (Though as an engineer I fail to see how!). So it is normal to have a few flat topped teeth.

If you are certain the hub is ok, then the only thing left is the chain. Get a new one. If the fault is still there, you can at least exclude the chain as the culprit.


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## Gerry Attrick (8 Jul 2009)

Bigtwin said:


> I disagree. Follow the curve around and compare the gradient at the LHS to that one the RHS - I think there is a discernible difference to them - that's more than enough to get slip with a new chain. Bottom picture, hold a bendy ruler up to the screen.



I also disagree BT. See my response above. Manufacturers deliberatlely cut (or press) the teeth in irregular shapes. I queried a chainset on one of my bikes for the same reason, using the phrase "cut by a first year metalwork student", only to be shown an identical brand new chainset. There appears nothing wrong with the chainset depicted.


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## Bigtwin (8 Jul 2009)

Gerry Attrick said:


> I also disagree BT. See my response above. Manufacturers deliberatlely cut (or press) the teeth in irregular shapes. I queried a chainset on one of my bikes for the same reason, using the phrase "cut by a first year metalwork student", only to be shown an identical brand new chainset. There appears nothing wrong with the chainset depicted.




I'm talking about the sprocket, not the chainset.


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## mcb2080 (8 Jul 2009)

Cheers Gerry and Bigtwin for all your input.

I am going to take it back to the bike shop on friday and get them to check the chain ring and the sprocket again as well as getting them to check the wear on the frame where the washers go as I still think this may be the problem as I say that I have had a slipping chain almost from first owning the bike.

The only thing with the half link chain would have allowed me to push the wheel as close to the pedal side and I could have tightened the washers on to a fresh part of the frame that hasn't been tightened before hope this makes sense lol)

Cheers


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## Gerry Attrick (8 Jul 2009)

Sorry Bt, can't see where you mean. There seems no wear sufficient to cause chain slip to me.

Wear on sprockets tends to manifest itself in hooked teeth. I can see no evidence of that here.


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## Bigtwin (8 Jul 2009)

Gerry Attrick said:


> Sorry Bt, can't see where you mean. There seems no wear sufficient to cause chain slip to me.
> 
> Wear on sprockets tends to manifest itself in hooked teeth. I can see no evidence of that here.



The valleys appear to be unsymmetrical to me. Hard to tell for sure in a photo of course - need to insert a rod to check. But if they are as worn as they look to me, then that's as, if not more, worn than I've had them causing problems.

Just on deduction, if it's had 800 miles done on that one sprocket, I'd be rather surprised is a new chain _didn't_ cause some problems.


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## swee'pea99 (10 Jul 2009)

Forgive my ignorant input (I'm not being cute...compared to most hereabouts I know nuuuthing) but sometimes the right amount of ignorance can actually help...seems to me that if it's ok at first, and only goes pear-shaped after 50-60 miles, it must be something that's changed over the course of those miles. Which for me at least seems to rule out anything like wear, and suggests instead some kind of slippage somewhere in the system. When I built my fixie, I had a similar experience, which turned out to be simply the axle shifting very slightly in the dropouts over time. Since tightening the nuts with a 12" adjustable, the problem has completely gone away. Costs nothing to give it a try...?


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## Rohloff_Brompton_Rider (17 Jul 2009)

half link chain solved all my problems. they are more forgiving on tension, but it does make a weird noise, i like but some may not, same as hope hubs. i have a diamond back


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## RedBike (17 Jul 2009)

It sounds like your problems are because the back wheel is slipping/ moving in the dropouts. You can see where frames worn as this has happened. 

If the wheel is moving then fitting a half link chain (or any new chain) isn't going to solve your problem. 

I would use a new set of track nuts and ask about the posability of fitting chain tugs.


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## RedBike (17 Jul 2009)

Your chain should be tight enough so the chain doesn't sag but not so tight as it impedes rotation


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