[quote:2hfovrxd]Just use the stock size. Eventually you'll run out of adjustment as the chain stretches and then you'll have to remove a link from the chain to continue using it.
I wouldn't use Primary Drive chains though, sorta cheap chinese crap. I've seen the o-rings crack and fall out of them after a couple rides because the rubber used in them is very cheap. I'd spend a couple extra bucks for a brand name product like DID. It seems like very few people experience what I saw with them, but I still wouldn't take the chance.
Thanks, I was hoping it would work with the same size in case I want to go back to 13/40 later. I would like a DID, but I'm prolly gonna have to skim by with the PD chain for now b/c I still have alot of other parts I need...
Unless I got the DID without an o-ring:
http://tinyurl.com/2mf4qz
The Primary Drive w/o o-ring lists a higher tensile strength, though:
http://tinyurl.com/2trr5t
or there's an RK w/o o-ring for cheap:
http://tinyurl.com/2rygoh
What the advantage/disadvantage of having an o-ring chain?[/quote:2hfovrxd]
I still say stay away from primary drive. Even if you go to a dealer you can get a Parts Unlimited X-ring chain for about $55, that's barely anything more than primary drive for one of the best chains out there. I don't know what places near you are a parts unlimited dealer, but several around here are.
You definitely want to go with an o-ring or x-ring chain. The o-rings are what keep water, dirt, mud, dust, and other stuff from getting worked into the moving parts of your chain, and hold the grease in. Unless you're very careful about what conditions you ride in, and closely keep up with the maintenance on it, a non-ring chain is going to last like 1/10th of the time a decent o-ring chain will last you.
Ok, so there's your benefits of the o-ring chains. The disadvantages are minor. Mainly cost, but also in theory o-ring chains have more rolling friction than a non-ring chain, and they weigh a bit more. The differences caused by weight and friction are so miniscule that there probably wouldn't be a measurable difference in power even on a dyno, much less so when you're actually riding it. X-ring chains are even an improvement over the o-ring chains. Less friction, and 2 mating surfaces to form a seal instead of just one.
I wouldn't worry about the tensile strength at all, that's hardly a concern even for guys running 4 times the power these 350's make.
