I have a Shimano 5 arm 110 bcd crankset with a round 26t and biopace 44t and 50t chainrings (I couldn't stand the small bio pace ring) on a rebuilt '88 Schwinn Voyageur. I've found that the gearing gaps are too big for me riding in the mountains, with only six speeds in back. I'm also not to keen on the biopace rings, after trying them out for a while (I can't spin well with them). I'm having a tough time finding reasonably priced 46t and 50t chainrings locally, which should give me more useable gears. Would the Sugino alloy MTB rings (no ramps or pins) work well? Any likely issues? Id like to know before i place my online order. Thanks!

Kevin

I should add that both rings are listed as "outer" by Sugino, and they only make up to a 46t middle.

Half step + granny is my preferred way to set up wide range gearing for the road.

The smaller gap middle to large ring makes for smooth shifting without needing ramps or pins, though the shift out of the granny may be sluggish. OTOH the premise of the HS+G configuration is that you don't use the granny so much, and so can live with the lest than perfect shifting out of it.

There may be issues of tooth offset which may let the chain snag between rings, but if I remember Sugino rings have teeth centered, so mirroring the 46T outer for use as a middle shouldn't be a problem.

Thanks FB. And, the granny is a bailout device. I'm in it just a few times a ride, when the going gets really steep.

what will you be shifting with?

I quite like the half step / granny setup on my tourer.

Shimano down tube friction shifter.

My bikes are set up that way, but I refer to it as half step gearing plus a bailout. On my touring bike the RD doesn't have enough capacity for chain take up so the bailout can only be used with the inner half of the cassette.

If the new setup doesn't work out for you, put the rings up for sale in the Classic and Vintage "for sale" thread at a reasonable price and you'll be able to recoup a likewise reasonable amount of your investment. Make sure you get 6/7/8 speed rings. Good luck.

I leave the less obvious details to FBinNY, who is well known for his knowledge on this site.

Yea You can get away with Un Ramped chainrings with friction shifting , fine..
I've never chosen to leave that setup.

Sugino CR, is made in one go, a stamped gear cut, so alloy is softer
to allow that manufacturing cost expediency .

The 6 speed wide range freewheels worked well in half steps together.

once the more is better 9 + speed cassettes came in the gaps were filled.
then half steps were not so good.. as lots of ratios became redundant.