Is there a way to confirm that my new chain is the right size?

[cutler26]

So recently I've started using my Merida One forty.7 500 for my daily commute, about 25 miles a day, I know it's not what the bike is intended for but I'm just using what I've got. So today I replaced the chain because I had stretched the old one and didn't want to cause more wear to the cassette than necessary. The chain I have gone with is the kmc x10 (This came in a generic bag) as it is what I have been using since I got the bike, however the chain was a pain to index properly when setting my gears up again today and whilst riding doesn't index properly in gears 5 to 10 I feels like the chain is stuck on 2 cogs at the same time (I'm pretty sure the cassette is still in good condition and the teeth aren't too worn) after getting the bike home I checked the width of the new chain against the old and it does seem to be ever so slightly wider. Is there a way to conclusively check the speed of the chain I bought, as it came in a generic bag and the listing did say 10 speed, I know it might seem wider than the old chain because the old one has stretched.

 

[huggy]

What letters and numbers are stamped on the links, I doubt an old chain would be narrower it doesn't stretch like an elastic band. The links wear there for moving apart.

 

[Yellow Saddle]

If you have a vernier you could measure it. However, the easiest way to make sure it is not a 9-speed chain is to look at the way it is riveted. On a 10-speed the rivets will be absolutely flush whereas on a 9-speed the rivets will have a slight protrusion. The only problem with this method is that it won't tell you if it is a 10 or 11-speed chain you are feeling up.

 

[Ajax Bay]

Your STI/rear derailleur is still shifting this chain sideways the correct amount (per index click), irrespective of the width of the chain. So even if the chain is the 'wrong speed' the symptoms you describe should not result. Setting up the RD can require significant patience.

 

[freiston]

Your STI/rear derailleur is still shifting this chain sideways the correct amount (per index click), irrespective of the width of the chain. So even if the chain is the 'wrong speed' the symptoms you describe should not result. Setting up the RD can require significant patience.

Whilst I agree that changing the chain should not affect the indexing or cause it to need re-adjusting, wouldn't a wider chain cause the symptoms described on account of the chain not settling onto the teeth of the sprocket effectively or efficiently?

 

[Ajax Bay]

OP said:

the chain was a pain to index properly when setting my gears up again today and whilst riding doesn't index properly in gears 5 to 10

So it was OK in 'gears 1-4'.

wouldn't a wider chain cause the symptoms described on account of the chain not settling onto the teeth of the sprocket effectively or efficiently?

Chain settled OK into gears 1-4. This is therefore very likely a straightforward (following logical sequence of set-up steps with patience) an indexing issue. One size different (ie wrong) width chain will end up with rubbing/friction but will still work, rather inefficiently.

 

[fossyant]

You may have been sent the wrong chain. It's usually printed on the links with regards to width.

 

[freiston]

OP said:
So it was OK in 'gears 1-4'.

Chain settled OK into gears 1-4. This is therefore very likely a straightforward (following logical sequence of set-up steps with patience) an indexing issue. One size different (ie wrong) width chain will end up with rubbing/friction but will still work, rather inefficiently.

My thinking was that unless the cassette is particularly close-ratio and especially if it is wide-ratio, then the vertical distance between gears 1-4 will allow the chain to sit better than it would on the smaller rings where the distance between the bottom of the teeth from one ring to the next would be shallower - maybe even shallower than the chain - more room for an oversized chain on the low gears, less room on the high gears.

 

[Yellow Saddle]

My thinking was that unless the cassette is particularly close-ratio and especially if it is wide-ratio, then the vertical distance between gears 1-4 will allow the chain to sit better than it would on the smaller rings where the distance between the bottom of the teeth from one ring to the next would be shallower - maybe even shallower than the chain - more room for an oversized chain on the low gears, less room on the high gears.

I think if you have a good look at a cassette you'll see that scenario is not feasible.

 

[freiston]

I think if you have a good look at a cassette you'll see that scenario is not feasible.

But that's the thing - when I look at a wide ratio cassette (and I think the OP's bike has an 11-36 on it) - it does seem feasible to me. This might not be the same cassette as the OP but I looked for a photo online and found this - there is a lot more clearance from the next ring on the four big rings than the five small ones - if I had one to hand with an oversized chain, I'd be better informed:

 

[Yellow Saddle]

The clearance required is in the distance between sprockets and that clearance is constant between all sprockets. Maybe I don't understand what you mean.

 

[fossyant]

There is no difference in clearance between sprockets. If the OP has a chain that's too wide, eg. an 8 speed chain on a 10 speed cassette, it will foul the sprockets.

 

[freiston]

I was thinking that a wide chain would still sit on the larger ring if the next ring was small enough (diameter) not to get in the way - that as long as the teeth can fit between the chain plates then the gap between the sprockets would not factor because the next sprocket would be small enough (diameter) to not foul the chain - at least as dramatically as it would on the higher gears where the differences in sprocket diameter is less and the sprocket teeth overlap more. But if I had a cassette and oversized chain to hand, I wouldn't thinking or wondering about it, I am only going by pictures and imagination, so please excuse me if I appear to be obtuse.

 

[Ajax Bay]

If the OP has a chain that's too wide, eg. an 8 speed chain on a 10 speed cassette, it will foul the sprockets.

I agree, but the symptoms described would likely occur across the cassette, not just on one half.

if I had a cassette and oversized chain to hand, I wouldn't thinking or wondering about it,

But you are thinking or wondering about it.
A 7-8 speed chain will work (with rubbing) on a 9 speed cassette. (but see 9 speed chain on 10 speed cassette calculation below). I have just checked on one of my children's bikes. And the shifter is, of course, 9 speed so the indexing continued to work from smallest to largest sprocket. I would not ride it like that though.
From Sheldon:
Brand and model Center-to-center Spacing Sprocket Thickness Spacer Thickness
Shimano
8-speed 4.8 mm 1.8 mm 3.0 mm
Shimano
9-speed 4.34 mm 1.78 mm 2.56 mm
Shimano
10-speed 3.95 mm 1.6 mm 2.35 mm

The space between sprockets 'two apart' ie not adjacent on a 10 speed cassette (like the OP's) is [2x3.95 - (2 x 1/2 of 1.6)] = 6.3
A 9 speed chain will not fit on (as it's 6.6 - 6.8mm wide).
From wikipedia:

• 6 speed – 7.8 mm (5⁄16 in) (all brands)
• 7 speed – 7.3 mm (9⁄32 in) (all brands)
• 8 speed – 7.1 mm (9⁄32 in) (all brands)
• 9 speed – 6.6 to 6.8 mm (1⁄4 to 9⁄32 in) (all brands)
• 10 speed – 6.2 mm (1⁄4 in) (Shimano, Campagnolo)
• 10 speed (Narrow) – 5.88 mm (7⁄32 in) (Campagnolo, KMC)
• 10 speed (Narrow, Direction) – 5.88 mm (7⁄32 in) (Shimano CN-5700,CN-6700,CN-7900)
• 11 speed – 5.5 mm (7⁄32 in) (Campagnolo, KMC, Shimano CN-9000)

 

[fossyant]

Chain line would affect it, causing it to skip on one half and not the other ! Also the ramps on the sprockets would try and shift an overly wide chain.