Aftermarket chain tensioners for dropouts without them.

[chriscross1966]

One of the joys of folding bikes is just how off-piste you are when you start modifying them... So before I fire up the lathe to bodge something up is there anything I can get off the shelf to add an axle repositioning feature to a dropout that lacks it? I've just had an 11speed Alfine wheel shoehorned into my Brompton on a custom rear triangle, but with the axle at the front/top (its diagonal) of the dropout the tyre is fouling the bottom bracket just at the end of its swing forward. It makes for an insecure fold. This will be complicated by the requirement to accommodate the Alfine's anti rotation washer....

Chris

 

[fixedfixer]

Recently sold an Airnimal Rhino with a sliding drop out system. It was designed to accept both hub and standard gears and give some chain tension ability by moving axle back a bit. This is my only photo as bike now sold and living in Germany.

 

[fixedfixer]

BTW don't Kinetic's do a similar rear triangle for the Brompton - maybe email Ben and ask him what they do and if he has parts he can supply.

 

[MichaelW2]

Most of the axle tensior dropouts replace std vertical dropouts. You can get sliding and pivoting ones. If you want to fit one to your Brommie you will have to replace your current dropouts with some cut and shut welding or brazing. Since Brommies require a sprung chain tensioner for folding it is one of the bikes where special dropouts have no special advantage.

 

[fixedfixer]

Hadn't appreciated the fold axis on the Brompton. Distance between BB and drop out on Rhino remaind same throughout fold.