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i fancied building a single speed bike
bought a DMR single speed kit which inc a 16t ring
running a 32t front ring
QR drop outs.
install as per instructions with the chain going round the rear ring and over the dmr chain tensioner - i couldnt get the chain tight enough so tried running the chain round the outside of the chain guide - still couldnt get the chain tight enough.
so i bought a 20t rear ring, same situation again (having added a link to the chain)
so i bought a 18t rear ring, now this is the best so far (link removed - so chain in the same length as when i tried the 16t) but still i cant get chain round the rear ring and over the chain guide as it should be.....
what am i doing wrong.... do i need to change the front ring to 30t??
Are the dropouts ajustable?
You need to tension the chain somehow
dropouts arent adjustable
the dmr kit has a guide that fastens to the derailleur hanger but it doesnt seem to work for me as dmr intend it to be used
Do you have pic of the setup?
Take some links out of the chain to get it tighter?
Might need a half-link, although that would be unusual when using a tensioner.
Charliethebikemonger used to have a good video on his interweb site.
my set up looks very much like [url= http://www.mtnbikeriders.com/2008/07/15/red-rocket-single-speed-update/ ]this set up[/url] but i thought the chain had to go over the chainguide rather than under it???
chain still seems 'loose'
It can do either, but over gives better chain wrap so less likely to slip. It should all work fine with 32:16 so not really sure what could be wrong. Any photos of your actual set up?
+1 Charliethebikemonger
[b]
I use a simple tension seeker, run it underneath at the limit of adjustment. Whole drivechain is worn well beyond normal limits. Works fine. Tried mine pushing up but there was more adjustment down than up and I can't quite get another link out.
Put it under, it'll be fine.
The 'half-link' is your friend, young padawan
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Not the best picture ever, but I've got my DMR tensioner pushing upwards, and it works a treat (I am using a half-link chain tho').
I'd go with the suggestion to add a half-link and then running the chain over the tensioner.
If you get with SS'ing, the Surly steel rings / cogs are great (in my experience), they are thick and have usefully long teeth, and if you are obsessive about chainline (and/or want some colour in your spacers), the every useful VeloSolo people have a great spacer kit, which will allow much finer adjustment than the DMR kit (which comes in an assortment of colours).
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The chain doesn't need to be crazy tight either, just tight enough - some give in the system is necessary (although this can be a [i]very[/i] fine line, looking at some people's pictures online 😉 ).
Ah, one last thought - tho'it might not be relevant, but the DMR tensioner doesn't 'work' with forward facing semi-horizontal dropouts, but I'd be surprised if you have a MTB frame with that kinda dropout, as it's more a road bike thing.
Surly ss rings and rear sprockets are the best
Apart from maybe a eno freewheel but that limits hubs
Is the tensioner fouling the chainstay at all? I had this issue initially.
Charliebikemonger offers some niche chainring sizes if you need inbetween standard sizes e.g.35:17, 39:19 etc.
thanks for the help... half links look like a genius idea 😮
Try these..
The installation...
And this deals with chain tension.. And stuff.