newbie question bout vertical dropouts and no chain tensioner?
04-07-09, 12:52 PM
#1
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newbie question bout vertical dropouts and no chain tensioner?
im just getting an mtb frame and building it up. it has vertical dropouts though and i want to go singlespeed. i've seen lots of bikes on here with v drops and no chain tensioners. how do you do it? i dont want to use a chain tensioner if i can help it. is it a case of trying different cogs at the back and rings on front? is there a way to measure what combo i need before buying different ones? or is it just luck?
04-07-09, 12:57 PM
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Google "magic gear"
There's a nice spreadsheet out there to help pick a chainring/cog combination.
Not all bikes will have an acceptable magic gear for the required ratio, and things start to go south as your chain wears. Chain tensioner takes all the fiddling out of it.
There's a nice spreadsheet out there to help pick a chainring/cog combination.
Not all bikes will have an acceptable magic gear for the required ratio, and things start to go south as your chain wears. Chain tensioner takes all the fiddling out of it.
04-07-09, 01:10 PM
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another option is to use an ENO eccentric hub for the rear wheel, this is a bit more expensive, but will give you the ability to tension your chain
04-07-09, 01:25 PM
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1) ENO hub - works perfect. Expensive.
2) Find magic gear ratio included the use of half links for the chain. Works well until the chain stretches over time. Then you have to fiddle again.
3) Use a chain tensioner (Surly Singleator is a good one, the cheap ones bounce).
4) DIY. Use old derailleur and jerry-rig your own chain tensioner.
2) Find magic gear ratio included the use of half links for the chain. Works well until the chain stretches over time. Then you have to fiddle again.
3) Use a chain tensioner (Surly Singleator is a good one, the cheap ones bounce).
4) DIY. Use old derailleur and jerry-rig your own chain tensioner.
04-07-09, 02:03 PM
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I found 2 combos that work on my stumpjumper. 44x16 and 34x17, one for city and one for dirt.
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I'm not one for fawning over bicycles, but I do believe that our bikes communicate with us, and what this bike is saying is, "You're an idiot." BikeSnobNYC
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04-07-09, 03:01 PM
#6
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well i wont be getting the eccentric hub. cheapest i've seen is about 100 quid. Good tutorial on 63xc.com here
https://www.63xc.com/toddp/halflink.htm
i'll have a go at that and failing it might pop into the local bike shop and ask for help
Saw also the magic gear calculator on mtbr. might have a look at that once i get my frame. thanks for all the help. i'll keep you posted and might be posting here a bit.
Have the specs for the frame and the chain stay length is 420mm so when i put this in here
https://eehouse.org/fixin/formfmu.php...ey=Stay_length
which ratio would ye use for this. 52x18 pops out at me but might be a bit too tough? 42x19 might be better but not exactly in centre of the shaded area.
https://www.63xc.com/toddp/halflink.htm
i'll have a go at that and failing it might pop into the local bike shop and ask for help
Saw also the magic gear calculator on mtbr. might have a look at that once i get my frame. thanks for all the help. i'll keep you posted and might be posting here a bit.Have the specs for the frame and the chain stay length is 420mm so when i put this in here
https://eehouse.org/fixin/formfmu.php...ey=Stay_length
which ratio would ye use for this. 52x18 pops out at me but might be a bit too tough? 42x19 might be better but not exactly in centre of the shaded area.
Last edited by breadbin; 04-07-09 at 04:33 PM.
04-09-09, 05:47 AM
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There are also adjustable BB's available. They work liek the ENO hub but on the BB side of the chain.
04-09-09, 06:32 AM
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Another way to create adjustment for the chain is to use a quick release axle and then cut the axle off at the end of the locknuts. Check here for more info, scroll down to the section on dropouts and then start reading at the picture of the hub with the cog on it.
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