Surly singleator chain skipping

Hi all,

Almost finished putting together a single speed bike for my dad and i've got a problem with the chain tensioner....

Chain goes round fine without any load but as soon as i pedal, after about half a revolution of the cranks, the tensioner starts to rise up and then final drops and causes the chain to skip.

Anyone had this problem before or knows what might be causing it?

Cheers.

Should be alright if its new?they tension with a cone wrench surly tool which if you haven't got would be worth fiddling with in a shop.

Check your chainline too.

Chainline is probably off. Could be stiff link. You can reverse the direction of tensioning with those so if it's not chainline you could try switching it to keep the chain closer to the cog.

Ok cheers for the reply's.
Its second hand but doesn't look too used. Got an 18mm cone wrench and tensioned it.

I'll double check chainline. Do you need another spring or can you turn around the one thats already in it?

Different spring
http://surlybikes.com/uploads/downloads/1x1Singleator_old.pdf

Just had another fiddle with it.
Took the tensioner off and found it skips without the tensioner there as well.

Off the bike, i rolled it along whilst pushing down on the pedal and after about 1/5 turn of the cranks the tooth of the sprocket would start lining up with the rollers of the chain then finally drop back in between the rollers again!

Its probably because the chain was too slack but i don't understand why it was happening with the tensioner on and the chain in good tension?

Anyway, i read a bit about magic gears and messed around with some fixed sprockets i had and got it to fit perfectly in the dropouts with perfect chain tension!

Only problem is the gear is a bit high. Am i right in thinking a 46x18 ratio will have the same amount of chain as a 48x16 but a lower gear?

Almost done.

Rear cog worn.

Rear cog was brand new.

not sure if this will help but i had a very similar sounding problem with a singleator a while back. i shortened the chain by one link and it worked perfectly.

SDW, you asked "Am i right in thinking a 46x18 ratio will have the same amount of chain as a 48x16 but a lower gear?"

Yes, you are right. You are not the weakest link.