thebankman

I've got a single chainring to install on a single speed bike. The current install is not aligned perfectly, thus there's a "high point" and "low point" while pedaling and it makes for a serious tight spot, only ridable if there is slack chain tension.

My question is, does Park or another company make a tool that helps to help align the chainring on the crankarm? Are there shims which can be used to get the chainring perfectly in the center?

If it matters, it's a Surly ring on old Suntour X-1 crankarms.

God bless you for your answers

Retro Grouch 

A trick is to loosen the chain ring bolts so they are just finger tight. Then install the chain and spin the crank several times. The idea is to get the chainring to move away from the tight points. After you get the crank spinning smoothly, snug up the chainring bolts and you're done.

thebankman

That's an enlightening trick...gonna go to the garage and try it now

Thank you!

thebankman

Sorry it's been a while since I replied...this didn't work. The motion of the chainring moving kept pulling the chainring out of alignment. So I removed the chain and started again to try and get the chainring perfectly centered. This worked ok, it's better, but not perfect. What kind of shim could I use to get this thing on perfect-like? I'm riding my other bikes for the moment, and it's driving me crazy I can't ride this one as it's my favorite.

Bill Kapaun

I think I'd repeat the first "technique", but with the bolts just a bit snugger.
When the chain is at maximum tension, tap the very front of the ring toward the rear with a rubber mallet.
Repeat, using lighter blows.

brooklyn_bike

i know this can be tough. i started doing conversions a couple years ago and have since done about seven for myself and family members. there are some chainrings and cranks that are less round than others and although the sheldon brown method of centering the chainring on the spider will help a bit - it won't solve significant runout. its hard to tell ahead of time which cranks will have less runout. in my experience the shimano 105s and 600s were less round than the few sugino crank/chainrings i've worked with. i also hate to say it but generally the nicer the cranks/CRs the less runout you'll experience. in the end i realized spending a little more money to save myself the hours of hassle is worth it. plus i've thrown a few chains that were too loose too avoid binding - a big downside. hope that helps.

tellyho

Sheldon describes the technique for addressing this problem here.

thebankman

Once again, Sheldon Brown thought this out long before any of us had the problem

Thanks to everyone who posted, I've got options now