Steev

I'm building up a cross frame as a spare bike. I wanted to keep it cheap and simple using stuff I had around the garage, so I thought I'd go with a 1*7. I've got it built up, got the chainline dead straight to the center cog on the cassette, everything seemed good on the test ride around the block, but this morning the chain would not stay on the chainring when in the 2 largest rear cogs.
Have I been optimistically naive thinking I could get away with no chain ring sort guide?
I'm going to change the chain ring to a smaller one anyway, would getting it non-ramped help?
Any other ideas?
Thanks

Francis Buxton

You may have too much chain. That's the only thing I can think of. I run a 1x8 mountain setup with no problems.

HillRider

Set the chain length correctly to see if that helps. A lot of single chainring users fit a front derailleur as a chain guide. You don't have to hook it up or provide a shifter. Just center it over the chainring with the limit screws.

Steev

Thanks, you guys pointed me to the right spot. I looked at the chain last night to check its length and finally realised that the spare chain I had put on was a 1/8" track chain, DUH. When I put the correct type of chain on, the problem was solved.

white lobster

I'm not so sure that you've solved your problem. If you have a rear derailleur, you're going to need some sort of chain retention device in the front. When you ride on the rough stuff, the chain will go slack and it will fall off.

A couple of years ago, David Millar's mechanics had the brilliant idea to remove his little ring and his front derailleur to save weight in the TdF prologue. Predictably, his chain fell off within sight of the finish line and he lost the race. I was stunned that a pro mechanic would make such a bush-league mistake.

HillRider's advice is good. Find an old junked front derailleur and set the limit screws to center it over the chainring.

erader

in the recent past i have run 1x7, 1x8 and now run 1x9. with just a chainring guard the chain only opos off when it gets bumpy.

so i now also run a third eye and hey chain NEVER falls off.

so....ring guard (takes the place of big ring) and third eye is my vote.

ed rader