I put on a rear sprocket w/ more teeth then stock. How do I set the chain length?

Question

Hey y'all

I've got a 2002 Suzuki Bandit 1200, and about 5 months ago I changed the chain and sprockets. The stock gearing was 15/45 with a 110 link, and I changed that to a 15/47 and broke the chain at 112 links.
After install, I adjusted the chain tension, and the tensioners were out a little more then 1/2 way. I thought with a brand new chain and brand new sprockets, the rear axle and tensioners should have been all the way in, but they weren't.
The original chain that came on the bike from the factory lasted 5 years, but the replacement lasted only 5 months.

My question is, how do you set the correct chain length when changing sprocket gearing from stock, and what's the worst that could happen with breaking the chain down to a lower length, say 108 links?

Ok, thanks so far for all the replies, I'd just like to fill in a few details.

I used an RK530 O-ring chain with new Vortex front and rear sprockets.
The parts being so expensive, and the job taking so much time, I slathered this thing with chain lube regularly. I keep a can of spray on under the seat so I can squirt some on there at the gas station.

And when I set the chain at 112, and adjusted the tensioners, the axle was more then 1/2 way back/out, towards the rear of the swingarm, the tensioners were at over half of their maximum adjustment. The wheel/axle was not all the way at the front. I had the oppostie problem.

A few more details:

I'm stranded at a hotel in Tennesse just north of Deals Gap, 850 miles from home. I rolled in last night with a stripped sprocket and chain that was dragging on the pavement. All the bike shops are closed today, so I'm having my dad send overnight some tools and my old sprocket.

I was going to break out a few links to get enough tension in there to drive to my final destination, and do a full chain/sprocket job when I get home. I just wanted to find out if there was anything dangerous, mechanically hazardous about using fewer links then stock.

The original sprocket is a 45, and I'll probably need to break 4 links out of this chain, it's that loose, bringing it down to 108.

No problem with that?

Answer 1

Just don't break the chain too short. Otherwise, it really shouldn't make a difference. I've done it many times - I usually found the minimum number of links I could get away with, then added 2 links "just in case" I screwed up somewhere.

Good luck!

Answer 2

no you should set the rear wheel about half way between front and back when measuring out the chain to cut. only going up 2 teeth in the rear you don't even need to change chain length, you could add 1 link if you want. To get the axle all the way up in the front of the swingarm you probably used LESS links, and then you probably set the tension too tight and couldn't loosen it because the wheel was all the way forward.

OK, with that added info, yeah, you're going to need to take some links out. Why did you add 4 links when you only went up 2 teeth? You didn't even need to add any links, it would have only move you're wheel forward 1/4". You should only have 1" chain slack up and down on the bottom run

BTW, when I said 1 link I meant 1 segment, which is 1 face plate and 2 rollers/pins links, I always make the mistake of thinking of each segment as a link when a link is actually the roller/pin. Yeah you can only add or remove in 2 link increments, but you added 4 when you should have only added 2 or none.

Answer 3

Definitely, sure. You should buy a whole set of each sprockets and chain almost always really affordably and this can be a quite convenient project to do. You see, as a series's rivets put on out the amazing period of the chain raises, which damages the sprockets. If you exchange the chain and simplest one of the vital sprockets, that ancient tired sprocket will put on your new chain approximately ten instances quicker than in the event you spent just a bit bit extra to switch the complete lot!

Answer 4

First, the tensioner should be in the middle of the adjustment (maybe slightly towards the inside). Engineers design with a plus and a minus so your tensioner has a plus and a minus to the adjustment.


There is a mathematical method of calculating chain length. However, as you are forced to make changes in 2-link intervals, a hyper-accurate calculation is not applicable.

The method you used was correct (+ 2 teeth = + 2 links).

Probable causes of your premature chain failure:
1. sprocket/chain misalignment
2. low quality chain - unfortunately it happens
3. a non-o-ring chain was installed where an o-ring chain was installed and then the chain was not lubed every 300 miles
4. wrong sprocket width/poor quality sprocket as to tooth versus chain size

As long as you can run the adjusters far enough in, you could go with 108 links, but I don't see any advantage.

RJ

Answer 5

Another possibility for premature chain failure - improper chain slack (adjustment to tight).
Every manufacturer & model, motorcycle & quad have different chain slack specs.

Lengthing, or shortening the length of a chain because of a sprocket change, will have no adverse affects on chain ware.