Chain Tensioners Pfft!

I'm sure this has been posted a couple hundred times on this forum and no doubt was coded by one of you but I just found it and its made me a real happy man. Could be some other people are new to building SS's too and will find it useful.

http://eehouse.org/fixin/fixmeup.php

I bought a 'singleator' due to having vertical rear drop-outs on my frame. I'd been feeling a bit short-changed though as my drivetrain was being 'polluted' by unnecessary hardware. I started to think about Sheldon's talk of magic gear combinations and googled til i found this. Still need to measure my chainstay to see what I can get away with (and could very well only be left with a choice of granny-lame or super ironman crank-king ratios) but hopefully something will come out of this that'll keep this cheesy smile on my face.

bah. cant get a nice gear ratio out this lot for my setup. nevermind. having installed the singleator now, I'm actually not disliking it quite like i thought. it has a certain charm

anyway.. ignore me. still worth bumping that link though for vertical-drop mans dem ;)

Hi Guys,

Sorry for digging up an old post but the nursery thingie won't let me start a new thread yet.

I've been lurking here for a while; oggling at the iron horses in bike porn and also learnt loads (so thanks for all of that)! But I have a question that, for the first time, cannot seem to be answered by search...

I got smacked off my bike by a lane-hopping motorbike yesterday which, ironically, was my first time back on two wheels since getting taken out [head on] by a police car in a hurry back in May - landing me a stint in UCH and months in casts.

This time I bounced pretty well and came off OK but my bike died. Before May I'd been riding the same old red Falcon as a singlespeed for 6 years in London and it couldnt have been easier, now I'm on my old Kona MTB until I have the pennies to build another roadbike, and yesterday's miss-hap has snapped my rear derailer and wedged the chain so tightly between the crank and the front derailer that I need to abandon the entire chainset and start again.

In six years my chain never fell off, nor did I ever long for gears... so they're going. The catch is the uber-vertical MTB drop out...

I know I could get a tensioner and if I could afford an eccentric hub I'd be able to afford most of an old roadbike again - my question is, has anyone thought up any cunning ways of keeping the chainline free of obstacles and keep a good tension? (I just can't shake the idea some sort of bolt-on conversion bracket or something?! Am I barking up the wrong tree?)

Sorry, this became quite an epic post but thoughts or experiences would be greatly appreciated as I really really want to get back on a bike and off the super-shitty 388.

Cheers!

Do a search for magic gear, it'll be about the best you can do.

Unfortunately bolt on tensioners are a really bad idea for fixed as they screw up with the backpedal/resistance of momentum.

a head on with a police car! then a motorbike ! gawd... i feel sry for ya, seriously i do !

but yes, you can find a "magic" gear as described above, with halflinks if need be.
the best way to find that gear is to experiment, with different cogs, as i did with a 8spd cluster at the back.
that willl allow u to go FIXED.
After a while though you'll find that the chain will stretch a bit. otherwise keep a beady eye out for a Eccentic Hub.... hard to come by cheaply.

on the other hand
you can use a springed tensioner or a non springed tensioner... both work in the same way but only allow u to go SS (thats important!).

any problems just ask... we've all been there, well most of us.

did you break a mirror or something ? don't give up on the cycling, two bits of bad luck means hopefully a few years of trouble free cycling !!

If you can get a bit of money together Ted at fixed gear London will swap out the dropouts and put track ends in for you I think he charges around £50. Then you could run whatever setup you fancied, 26" or 700c wheel will fit. If you go with 700c for a front brake you can either swap out the front forks for some road ones or use some puals components brakes (expensive) or set it up lo pro style with 26" at the front and 700c in the rear. I've seen a couple of old kona mbts converted to fixed gear roadish bike and it seems to work really well. Solid bike and not too heavy.

Just found these. Allow you to run 700c wheels in a mountain bike frame and still use you canti / v brakes. They move the bosses higher.

http://www.google.co.uk/products?q=Mavic%E2%80%99s+caliper+adjusters&um=1&ie=UTF-8&sa=X&oi=product_result_group&resnum=5&ct=title

Run it as a single speed with a tensioner. I had the same problem with my mountain bike when I went s/s. U can use Half Links to lengthen/shorten the chain, and try to find a magic gear as per Object's advice above.

Thanks Guys... all really helpful stuff.

I think I will try and run it SS as I'm a bit of a sucker for pulling the back end out for nothing other than show and I'm currently riding really wide Schwabble slicks on 26"s which will basically ruin any chance of stopping it if fixed... it'd be a funny sight seeing me try though!

I'll look into this whole magic gear thing, I didn't realise that was possible on a fully vertical drop out - only the semi vertical ones? My mistake.

I'm just desperate to avoid chain tensioners, sprung or otherwise, I know they work for S/S's perfectly well - they just stop the bike looking as simple and lean as it could and after a childhood of BMXs, there isn't much better than a lovely, clean, tight chainline!

I need to get over myself and get the bike fixed - ASAP.

Dicki - The blind arsehole didn't even stop and it was a car two back that finally stopped to see if I was ok!! Where is the shivalry these days?!

(Tommy) - When you say 'swap the drop-outs' do you mean cut out and replace? Yikes! Surely that must mess with the strength of the back end?!

(Tommy) - When you say 'swap the drop-outs' do you mean cut out and replace? Yikes! Surely that must mess with the strength of the back end?!

No, if it's a steel frame (which I think those old konas are) and done well it's no problem, that how they are put together to start off with. I did it on a mtb in a really hack way, not properly like Ted does and I have bumped it up and down curbs done some small sets of steps, rode down some bigger sets of steps and it's fine.

Magic gear link.http://eehouse.org/fixin/

Wow! That's pretty cool. I think it is a steel frame. It's a Cindercone and I think... '95 or '96. Bikepedia, in fact, confirms - yip. Steel.

Will I still be able to run a rear V with the new positioning? So many questions...

Well regardless, maybe that's the way to go for a good long term resolve?!! How do I find Ted? Is that his user name?

Cheers for this!

Will I still be able to run a rear V with the new positioning? So many questions...

If you stay with 26" wheels no problems. If you go to 700c wheels you will need pauls components brakes or one of these
http://www.google.co.uk/products?q=M...num=5&ct=title

Well regardless, maybe that's the way to go for a good long term resolve?!! How do I find Ted? Is that his user name?

Cheers for this!

He is not on this forum.

Go to the fixedgearlondon website and have a look around for riders and find ted. I think his mail is ted@fixedgearlond.com but not sure.

The only thing to be careful about is chainline on a mbt. Sometimes chain rings hit chainstays when going for a track 42 mm chainline. I just used a hub with a wide mbt chainline (one one mbt fixed hub or single speed hub with a fixed cog on the disk side for fixed) for this but Ted may have other solutions so talk to him about that too.

i just ripped up my cassette, made some spacers from some pipe found in my garage and just tried all the gears until i found somthing that worked. not ideal but it will work.

Cheers Guys.

I'm gunna hunt down Ted. I'll let you know how I get on!

In the meantime I can now be seen cruising about on a 52cm Raleigh Max, complete with all plastic components, reflectors, bullbars and (my personal favorite) an oversized, 90's, lead-weighted frame.

The humiliation is worth it.

Anything to stay off the 3 8 freakin' 8.

Oh nice one. I may do the same for my conversion. Beats waiting months for an eccentric on special order.

did you break a mirror or something ? don't give up on the cycling, two bits of bad luck means hopefully a few years of trouble free cycling !!

More importantly, with you on the road with your luck, the statistical chances of bad things befalling the rest of us are greatly reduced. Keep cycling!

[and stay safe]