Chain length calculation advice request.

[dazzler24]

Down the track a little bit I'm going to change out the sprockets and chain on my 2015 Tracer (FJ) .  Just wanted to get confirmation that the calculation I did meets with the nod of approval (or otherwise) from the experts out there.

Once that chain length is chosen there's no going back once it's cut if only to find it has to be longer!

Sprockets chosen are 16T front and 46T rear (+1 from standard)

Chain chosen is DID 525 VX3 (comes as a 124 link with a rivet type master link)

So, I've used the Chain and sprocket calculator to come up with the following result below which to my untrained eye seems just about perfect.

I base that on the following: -

1. Sprocket distance increases slightly over stock (~4mm) = good.

2. Wear rate is shown as 100% optimal front and back = great!

My only 'concern' is - does the chain have to be an even number of links or is 111 OK?? - OR does it then require a 'special' master link!

If it has to be even, then 110 or 112 links given my choice of sprockets?

Further calculations below would say that 110 links gives an even shorter wheelbase than stock but OK wear rate while 112 links provides for a long wheelbase but bad wear rate!

TIA

 

111 links -

110 links -

 

112 links -

[Lone Wolf]

10 hours ago, dazzler24 said:

... chain chosen is DID 525 VX3 (comes as a 124 link with a rivet type master link)

You can order chain with the length you want (to avoid having to cut it yourself)

This is from sprocketcenter.com

  

10 hours ago, dazzler24 said:

... My only 'concern' is - does the chain have to be an even number of links or is 111 OK?? - OR does it then require a 'special' master link!

" If the number is an odd number, then it must have a half link in it."

http://www.sprocketsunlimited.com/Chainspecifications.html

 

Don't use a half link - the axle adjustment will take care of small differences.

Edited October 13, 2020 by Lone Wolf

[dazzler24]

5 hours ago, Lone Wolf said:

You can order chain with the length you want (to avoid having to cut it yourself)

Yes, I've actually got the chain and it happened to come with 124 links and I'm OK with cutting it.  I bought that particular one as it was at a 'special' price that I couldn't go past at the time.

5 hours ago, Lone Wolf said:

" If the number is an odd number, then it must have a half link in it."

http://www.sprocketsunlimited.com/Chainspecifications.html

Don't use a half link - the axle adjustment will take care of small differences.

And yes, as suspected - a half link.  Don't want to do that but I'm back to the original conundrum of 110 OR 112 links as both will work but resulting in different wear rates and wheelbase lengths.

I'm thinking 112 links is my 'answer' unless advised otherwise.

Cheers.

[nhchris]

In the 112 link analysis above why is the small sprocket wear status red?

Be sure at 112 links that you have enough swing arm capacity to accommodate inevitable chain stretch.

[dazzler24]

1 hour ago, nhchris said:

In the 112 link analysis above why is the small sprocket wear status red?

I think it's showing the number of times the same tooth meets the same chain link.  111 links are 'perfect' as the tooth to link contact is evenly distributed to all of them - 16 revs on the front sprocket (16T) the same tooth will meet the same link in the chain and similarly for the rear sprocket 46 revs (46T) the same tooth meets the same link.  Therefor every tooth moves one link per revolution per sprocket.

As for the 112 link version it shows that the same link meets the same tooth on the front sprocket every 1 revolution of the chain while it's 50% of the time for the rear sprocket.

Hope that makes sense and I've got it right! 🤔

1 hour ago, nhchris said:

Be sure at 112 links that you have enough swing arm capacity to accommodate inevitable chain stretch.

Hmm... Just checked Gearing Commander and it suggests a 110 link chain with my proposed setup.  That shortens the wheelbase (when chain is new) by ~4.3mm.  Not a big deal I guess.

I might be overthinking this and may just go with the 110 link setup after all. As you suggest the chain will stretch over time anyway.

[bwringer]

I've seen over-calculation lead to more than one ruined chain cut too short. It's really hard to correctly count chain links, and it's pretty pointless if you have a chain in hand that's more than long enough.

You know you have a chain with excess length. That makes it easy. Install everything, screw the adjusters all the way forward, and place the chain on the rear sprocket, hold the ends in place, and see where you end up with proper chain slack. Then decide where to cut. Whether you end up with 110 or 112 links is entirely irrelevant.

Folks have been known to use chain length to slightly shorten or lengthen wheelbase if there's enough room in the adjusters, but that's in the racetrack realm.

[Junkie]

I was going to give the same advice as bwringer: mock it up before fitting the chain, and see if you have adequate slack with 110. If you do, run it. If you don't, run 112. Once you've figured it out, cut to length. 

 

A longer (effective) swingarm will slow handling somewhat, reduce wheelies, and soften the rear suspension. Not saying it's a huge amount, but it's there. 

 

Changing chain length by 2 links changes swingarm length by 5/8" or 16mm, or near enough to make no difference (the angle means it's a hair less). Internet sources state that the Tracer 900 has a 60mm longer wheelbase (I believe all in the swingarm). That means that they added 8 links. It makes the bike feel like more of a sport touring bike and less of a sportbike. Which one is right for you depends on what you're using the bike for. If it's mostly solo riding on twisty roads, you probably want the FZ/FJ swingarm. If it's for lots of 2 up and straighter roads, the Tracer swingarm makes more sense. 

 

Of course, 110 vs 112 is a much smaller change than 110 vs 118.