Single Speed Alignment question (Picture thread)

Ok, So i’ve replaced the make shift shimano chain ring with a Renthal 36t single speed jobby and I’ve offered up the new KMC chain but I have noticed the front/rear alignment is out. I think this might have been like this when I bought the bike 2nd hand and it might have contributed to the slipping and eventually snapped chain problem.

As you can hopefully see from the photos, i’ve put a straight edge against the chain ring and this is giving me a rough idea how far out the rear sprocket is.

I’m guessing I need to add some spacers? to the rear hub to bring the sprocket into line but is it ok for the rear sprocket to be so far out from the rear wheel?

Are velosolo spacers any good?

Where is the chainring mounted – on the middle ring or big ring position?

It’s mounted directly on to the cranks with short bolts…. Apologies if that makes no sense. So does that make it positioned on the big ring?

it’ll be fine nearer the dropout. you have cogs there on a ‘normal’ cassette anyway.

I took the view that the closer the cog was to the dropout the less stress the axle was under, in any event. (note I have no idea if there is any science to support this).

looks to me like you have the ring mounted on the outside of the cranks

also the small spacer on the freehub could be moved to the other side of the cog to improve the situation.

im not a fan of that spacer set up – several small spacers allowing fine adjustments much better than the 2 big ones and a little one you have !

womble72 – Member

It’s mounted directly on to the cranks with short bolts…. Apologies if that makes no sense. So does that make it positioned on the big ring?

On the outside of the spider where the big ring would be or on the inside of the spider where the middle ring would be in a triple?

Got a pic of the chainring?

I’m new to bike fettling so I’m sorry if I’m not correct with the terminology but yes, I think I have mounted it on the outside of the cranks. That would explain why there is a huge difference in the alignment. Is it better on the big chain ring position or should I move it to the middle ring position?

I’ll post a pic when I’ve had lunch 🙂 priorities. Ha Ha

will look nicerer (imo) outside but will give a better chainline with your rear cog inside.

is that a Halfords Pro socket set, they’re good aren’t they?

Is that a Singular Swift, they’re good aren’t they?

I have one and use a surly sprocket and spacer kit which works really well.

I think this might have been like this when I bought the bike 2nd hand and it might have contributed to the slipping and eventually snapped chain problem.

I doubt it.

If it’s a derailleur chain it should work OK, but always good to have it spot-on.

Yes just move the chainring to inside the spider on the crankset.

leave chainring where it is, which looks better anyway IMO, and move rear sprocket out. As surmised above this will put less bending stress on the axle. Not that there’s much anyway.

1/2 seatpost diameter + distance from seatpost to chainring = front chainline

67.5 + Distance from inside of dropout to cog = rear chainline

Move freehub spacers until they’re the same.

APF

http://www.velosolo.co.uk/shopsingle.html

Trim to your heart’s content, in any colour you like.

(would also recommend CTBM but he seems out of stock)

My Kona has a Surly ring on the outside of an old Sugino triple, with a Surly cog pretty much right out on the end of an XT hub using VeloSolo spacers and it’s fine. I can’t recall the length of the BB axle tho’ – but it’ll be a little bit shorter than it would be if I had it set up as a triple.

Your Swift looks like it’d be easy enough to sort out by just using more narrower spacers, rather than fewer, wides ones. The chainline doesn’t look *that* far off.

Not especially clear (as you can’t see all of the spacers 🙄 ) but my Kona looks like this: (The Surly cogs are a fair bit wider than some are tho’).