Chain - how many links!?

[Petej]

Hi

Chain time and need to order, how many links should a standard S2R800 chain be?

520 pitch, but length?

[stopintime]

With a 1% chance of me not remembering correctly - 104 links (like 104 pins)

[Petej]

Mate you will get a special mention when my bikes finished!! Thank you it's what I thought!!

Sprockets ordered, now chain time!

Cheers

[stopintime]

Actually, it's probably 103+1 to be more precise (the +1 being the rivet link), but this is still from me as an amateur. I have checked the parts catalog since we last talked and it does say 103+1.

What teeth count sprockets have you ordered? If it's a lot less, or more, than stock a different chain length might be required to put the eccentric hub in it's best area.

[Petej]

Brilliant! Be nice to get the rear end finished!

Sprockets - Standard. Other than a 14t front (what the bike was running when I bought it)

Your help is much appreciated!

Pete

[stopintime]

Ok - if by stock you mean 42 rear, I have horror pictures to show you of the sprocket wear you get from even numbers (on both.)

..., but I think stock is 41 even though Ducati describes it as 42.



EDIT: I think we found out that the alternate teeth wear pictured below is caused by an even numbered rear sprocket and is not related to the number of teeth on the front sprocket...

[Petej]

The front I took off had done 8k and only showing slight wear to be honest. I only use my bike for fun so do little miles really so will live with it this time round.

Yeah I counted the teeth it is 41, though Ducati say 42. Apparently they were 41 when sent out or so I have heard!

Pete

[stopintime]

Very good!

I'm going to show you anyway - ha ha

http://i329.photobucket.com/albums/l394/stopintime/14-40.jpg

[gary tompkins]

That sprocket damage is bad and looks like alternate teeth snapped off

Was that a steel or alloy sprocket?

[stopintime]

I don't know the material (not my bike), but yes it's alternate teeth. If you are curious about the math - check GearingCommander.

Below is my previous alu (14) 40 teeth which also had a small misalignment issue. Alu sprockets are especially vulnerable to misalignment. This is not yet worn, but it's easy to see that the chain grabs at the same spot all the time.

http://i329.photobucket.com/albums/l394/stopintime/DrevogBikeVis001.jpg

[Petej]

How do you check/ adjust alignment!? I've ordered a a carrier so I can switch sprockets. Your pic looks harsh!

[stopintime]

I use a Profi CAT laser tool - holding it flat on the sprocket and letting the beam/spot follow the chain - it should hit the chain at the excact same place all along it's run.

The S*R swingarm doesn't have any easy adjustments - so alignment issues would probably be caused by wrong parts and/or wrong procedure.

Changing carriers and sprockets isn't usually as problematic as on mine - don't worry.

[utopia]

That sprocket wear does look pretty horrendous.
I can't quite work it through in my mind, but it looks like perhaps the chain contacts the rear sprocket in the same place each rotation, or at least the narrower pair of link plates is always in contact with each alternate tooth, if you see what I mean.
I think that this might occur when the rear sprocket and the chain both have an even number of links, rather than even numbers of teeth on each sprocket, though like I said, I haven't actually thought this through fully.
That's a new one on me. I hadn't considered that before, but it does sound sensible to avoid that condition, so thanks for flagging that up. Its now stored for future ref.
Maybe that has something to do with the discrepency between the stated 42 teeth and the actual 41(with the 104 link chain)....ie they discovered their error late in the day and the specs had already been printed up....???
Mind you, as has already been said, that amount of sprocket wear does suggest that there is a misalignment. In the absence or a fancy laser device, or even to check that such a device is working properly, it might be worth checking the alignment with a simple straight-edge. A 2ft steel rule for example. I prefer the simple, non-tech methods as there is less chance of being deceived by an internal glich in the laser etc. Another check might be to lift the rear end and spin the wheel, observing the chain to see if it is pulled to one side of the sprocket, rather than remaining central. Not exactly an accurate test, but possibly a decent quick check that things are roughly in line.
Also, note that any realignment of the rear wheel will also affect front/rear wheel alignment, so that should be checked too.
Oh, and it might be a good insurance policy to fit a crankcase saver if the chain run is in any way suspect, or even if it isn't for that matter.

[stopintime]

I believe a chain will always have even number links, so the even/uneven happens at the sprockets.

My unique situation shouldn't be taken too seriously - the shiny wear on the outside was probably a result of it being a machined 525 sprocket ( = misalignment) which furthermore didn't have the usual amount of (sideways) tapered teeth, guiding the chain in.

My picture shows the pattern in the dirt and grease - the top picture just shows how an even/even chain wear will look.

I've had violent resistance from people about this and it's not important for me that we all understand, accept or bother. Most riders don't check or even lube their drive line. They ride until it's time for a bi-anual service, if that, and let the shop replace parts as needed. Most riders do maybe 2-3-4 K miles a year and if a sprocket needs changing after three years instead of six, it's not going to be an issue for them. My shop told me about a guy coming in to get new clutch plates - it was slipping bad, he said - turned out all of his rear sprocket teeth were missing. We all have different standards of maintenance...

[Petej]

''My shop told me about a guy coming in to get new clutch plates - it was slipping bad, he said - turned out all of his rear sprocket teeth were missing. We all have different standards of maintenance...''

That had me rolling on the floor! That's just brilliant!

[utopia]

I believe a chain will always have even number links, so the even/uneven happens at the sprockets.



Good point.
I told you I hadn't thought it through very far........:dizzy:

Now that I do.....
I guess that means that any sprocket with an even number of teeth will have the inner chain plates synchronised to the same teeth on each rotation, irrespective of the number of teeth on the other sprocket.
Not that you would expect a major problem from that....unless the sprockets were misaligned.
Although perhaps, as a general rule, you could say that sprockets with odd numbers of teeth would wear slightly more evenly. Even with everything in alignment.

Its funny how sometimes just a tiny bit of info about your machine can significantly affect your relationship with it.
In this case for example..... I have been toying with a 14T front sprocket instead of the std 15T but I'm moderately happy with the gearing as it is. However my cases don't have room to fit a case-saver unless I fit the 14.
I considered restoring the gearing by fitting a smaller rear sprocket, but that would worsen an already marginal chain clearance at the swingarm pivot.
So I had a dilemma, and was in limbo.
But now that I have the added reason of the odd 15T being just ever so slightly more sensible, its just enough to tip the balance in favour of keeping it.
I might even tweek the rear to the nearest odd number in my preferred gearing direction next time I replace the chain, if the current one turns out to be even.

As you say, such minutiae matter little for many people, as long as it lasts til the next service, and that is certainly as valid an approach as any other.
On the other hand, my bike is a keeper, so I hope to benefit from all these little insights at some point down the road, even if that goes little further than feeling more in tune with the bike.

I had a friend who had a BSA C15 with the rear sprocket "clutch slip" thing.
It was like a threepenny bit (legal tender at the time).

Anyway, thanks for the insight......:biggrin:

[stopintime]

............
I guess that means that any sprocket with an even number of teeth will have the inner chain plates synchronised to the same teeth on each rotation, irrespective of the number of teeth on the other sprocket.
..........


Sounds correct. That's not how I thought it was, but now that you made me check again...

It also means I need to change my understanding of the even/even horrors. The alternate teeth wear is caused by an even numbered rear sprocket - regardless of what front sprocket is on.

However, an even/even selection will heavily increase the frequency of the 'same tooth/chain position front+rear'. This is bad because once a link is starting to freeze or stretch, even just a little, it's going to wear out the sprockets faster.

The usual internet amateur warning applies, but I think we're getting closer...

My head hurts. Good night!