Replaced Chain Slipping

[harveymt]

I have put a new chain on my Triban 3. I replaced the chain it came with with a KMC chain. I counted the links on the old chain and shortened the new one to the same number of links. I had it on the stand last night, tried all the gears and it worked fine. Went out this morning to cycle and as soon as I tried to pedal the chain seemed to be slipping. The front cogs seemed to be slipping. I thought that meant it was probably too loose so I removed one link and tried again. This improved it a bit. I could get the bike to perform ok but as soon as I tried to put any sort of power through the pedals it slipped again.
Should I remove one more link or adjust something else?

 

[john59]

Worn sprockets or/and chainrings most probably.

John

 

[Tim Hall]

Most likely cause is the cassette (back cogs) have worn to match the profile of the old, worn out, chain. Fit a new cassette and it should be OK., You'll need a cassette tool and a chain whip.

 

[mcshroom]

I'd expect it to be the rear cogs rather than the front chainrings as the cassette tends to wear faster. Sounds like you've run the chain too long and the cassette is worn out. The old chain will have adapted with the cassette but the new one will slide out of the worn grooves under load. Sounds like time for a new cassette.

To give it a test, try putting the bike into a gear at the back you don't use very often and see if it is happier there.

 

[Paulus]

+1 for all of the above.

 

[raleighnut]

^^^^^^^ same here, cassette's knackered.

 

[Mile195]

+2.
You don't necessarily need to change the cassette every time you change the chain (Depending on your riding style of course), but it sounds likely that you need a new one this time as other posters have said.
I do 3 chains to each cassette, but change my chains when they're on the limit. If they're beyond the limit they'll wear the cassette quicker (as the links will no longer fit between the teeth properly, wearing them out) so you might want to consider changing this chain sooner to save money on cassettes.
The tool for checking chain wear costs about £3, so worth the investment really.

 

[mjr]

Or you could use a ruler on a chain under tension (bottom run on a derailleur): 0 and 12" should be on similar places on links. The amount it's out is how worn the chain is. I think change by 1/16" out but I'd double check that.

 

[harveymt]

I replaced the cassette with a new one. The slipping is still occurring. I put the bike in the middle cog at the front and it's ok. It slips on the big one. So it looks like the big cog has worn. Upon close inspection you can see the teeth on it noticeably different.

I could replace the whole thing as Decathlon have a replacement chainset for £20.

One thing I've noticed is the the gears are 50/39/30. I always cycle in the 50 bar a couple of big hills. Could I just get a new chain ring to replace the worn big one? And make it bigger, say a 52?

Off the top of my head the big one is 5 bolt with a BCD of 130mm. Would there be a 52 tooth replacement? Any links would be appreciated.

Cheers.

 

[mjr]

I think it depends on the chainset whether you can dismantle it or if it's one lump you have to replace entirely. Sounds like you may be wearing your chain (by twisting it to extremes) or knees prematurely if you're always in 50 tooth but maybe your riding conditions are especially easy.

 

[Nigelnaturist]

@harveymt you can get chain rings in a lot of sizes, if you change to an outer 52th ring it likely you will need to move the FD up a bit, I use to ride on a 52/40/30 chainset and have just replace it with a 50/38/26 and the next move is to get a closer grouped rear cassette, this will give me much the same gear range but much closer gears on the back ( I hate big jumps).
I agree with @mjray though it does sound as though you are staying on the larger ring long than is needed, I ride almost exclusively on my middle ring as this gives me a very straight chain line when spinning on the flat about 60-70" or 38 (middle on the front) and from 17-14 on the rear in single tooth steps, I use the inner ring 26th when climbing (though not always), when the chain would be on the 38th front and 24 or 27 rear, this being about 41-37" is the same as the 26 front and 17-19 on the rear again a better chain line and better options.

 

[harveymt]

The chain was worn as I did far too many miles on it. I'm only really learning the upkeep in the last few months. The chain stretched that much it deformed the front ring.

I have very strong legs from power lifting so being in the middle ring feels off to me. I feel like I'm spinning way too fast in the middle ring and going nowhere. I much prefer the larger ring.

Decathlon have spare chain rings. Stronglight I think was the brand. On the Triban 3 you can remove the large chain ring without removing the crank. It will slip off over the crank and pedals. The middle and inside ring you'll need to take the crank out. I got a 53t ring to replace what I had. Decathlon had replacement 50t, 51t and 52t. They weren't on the shelves but in the workshop, I had to ask for them. Don't think they're on the web site either.

The front derailleur did need moved up. In the middle ring I can get it adjusted so it runs ok in every gear bar the smallest cog, there's a bit of chain rub.

In the new 53t front I have an issue where I think the chain is too short. It's fine in every gear bar the biggest one, a 25. The chain jams when you try to put it in that cog. Looking at the rear derailleur it is stretched out as far as it will go. I have just put a new chain on and still have the links I removed. Can I use another quick link and add a couple of links on? Reading around some say it's fine others say not.

 

[Nigelnaturist]

@harveymt depends on the chain, I have put links back in on 7/8/9 sp, but it needs to right as it (as happens to me) possible for the outer plate to come of the roller pin and catch he FD cage. When adjusting the FD start with it the correct distance from the small ring with the shifter in the low gear setting, then it should move to each ring correctly, they may also be a trim function on the shifter, this is like a half click and move the FD to help compensate for the chain being at extremes.
You really shouldn't be on the large front and large rear anyway, but it is also right to make sure its working correctly just in case. When measuring a new chain, wrap it round front large and rear large without going through the RD and give one extra link (thats both bits), this should then be the correct size, however if you are working on extremes it is possible that this is to long for a small small combination as the the RD will go back so far the chain will then rub on the RD cage.

 

[harveymt]

I took it out for a spin last night. I wasn't able to get it set up correctly in the smallest ring. No matter what I tried the chain rubbed against the front derailleur cage. It's because I had to move up the derailleur to accommodate the bigger 53 ring. I never used it anyway so it's no great loss.

I added in two extra links which made the chain the correct length. It now doesn't jam in any gear.

I noticed on my run out that whereas on the 50t front cog I could move into the largest rear cog and keep going up hills with the 53t front it wasn't going to happen. I had to change down onto the middle ring. So going bigger has probably helped me maintain a straighter chain line.

Still not very happy with the shifting of the front derailleur. It goes from large to middle ok but going back from middle to large is anything but smooth. You have to push the gear lever way over as far as it will go to get it to shift. Sometimes it wouldn't and I had to release the lever and shift it again. The front derailleur has never really worked well on the bike, Triban's seem to have an issue there. Also the outer limit screw doesn't seem to do anything no matter how far in or out you screw it. So I don't know if my derailleur is at fault or I just can't set it up properly. I may leave it into a lbs to have a look at it.

 

[raleighnut]

Some front mech's don't like changing at a lower cadence try shifting when you're spinning a bit more.