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- Location
- The TerrorVortex
And the rear suspension would affect the chain tension. Obviously, you can't use a chain tensioner with a fixed.
- Location
- The TerrorVortex
Hang on...what's the date? 
12boy
Guru
- Location
- Casper WY USA
There is a gent who goes by little pixel who has done exactly this but retained the chain tensioner.
http://www.fixedgeargallery.com/2007/dec/3/HuwGwilliam.htm
He used a Merc frame but that is a Brompton clone so it should work with a brompton as well.
http://www.fixedgeargallery.com/2007/dec/3/HuwGwilliam.htm
He used a Merc frame but that is a Brompton clone so it should work with a brompton as well.
- Location
- The TerrorVortex
I always thought a chain tensioner with fixed was one of the big no-nos?
12boy
Guru
- Location
- Casper WY USA
Me too but apparently it works per little pixel....
mickle
innit
- Location
- 53.933606, -1.076131
No. Just no.
mickle
innit
- Location
- 53.933606, -1.076131
Oh, ha ha April Fool! You got me.
A Brompton fixie does make sense to me.
When the Brompton is unfolded, the chainring and sprocket should be the furthest apart from each other, so as the link shows above, the chain can be fully extended and virtually straight both on top (for accel) and bottom (for decel). The chain tensioner just gets pulled into a useless position when unfolded, and then becomes useful to take up the chain slack as the bike is folded and the chainring and sprocket get closer.
Suspension can mess with chain slack, but in the Brompton's case, it's movement is minimal, and the rear triangle hinge is very close in line with the chainring and sprocket - so just normal fixie chain slack should handle it.
I'd be careful on corners though... the Brompton seems low to the ground and you might strike a pedal if leaned in enough.
When the Brompton is unfolded, the chainring and sprocket should be the furthest apart from each other, so as the link shows above, the chain can be fully extended and virtually straight both on top (for accel) and bottom (for decel). The chain tensioner just gets pulled into a useless position when unfolded, and then becomes useful to take up the chain slack as the bike is folded and the chainring and sprocket get closer.
Suspension can mess with chain slack, but in the Brompton's case, it's movement is minimal, and the rear triangle hinge is very close in line with the chainring and sprocket - so just normal fixie chain slack should handle it.
I'd be careful on corners though... the Brompton seems low to the ground and you might strike a pedal if leaned in enough.
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We have a winner...I did think of it for a second TBH...But I already have two fixies of the non Brompton variety but this thread went pretty well,thanks.
Still turned out to be a bit of an interesting thread,cheers.
Ian H
Ancient randonneur
With a freewheel, the lower part of the chain is always slack. With a fixed-wheel, it can be under considerable tension—enough to undo most tensioners.
12boy
Guru
- Location
- Casper WY USA
April fool or not it has been done. I have tried to get rid of the tensioner just to see if it affects pedaling effort but never could get a chain ring/cog set up with the 12 tooth cog that would be the right tension. Perhaps an eccentric bottom bracket would do it but I didn't want to go that far as they are expensive.
