Deraileur post on KMX

[Andrew1971]

Hi All
Hi have a KMX Tornado and would like to fit a front deraileur from single to a triple chainset. Can't afford getting a new boom got save for a new car. Then came across this what is it and how does it fit. All advice is welcome.
Andrew

 

[numbnuts]

I can't see how that is attached even by blowing up the photo, I know you said you can't afford to replace the boom, but it can't be that expensive.

 

[Falco Frank]

Hard to tell,looks like a side pull MTB mech mounted on a plate possibly?

Is a new boom that expensive?

 

[Andrew1971]

New boom is £70.99 delivered. Just ebayed it. It fit's onto the bottom bracket
http://www.ebay.co.uk/itm/Shimano-D...36291ef&pid=100005&rk=5&rkt=6&sd=271422388577
Only goes to 44 teeth i have 48 teeth biggest bugger iam a sad panda

 

[voyager]

It depends on how clever you are and how adaptive you can be

The KMX boom is a square boom , the position of the changer mech needs to be in the right place ( check the position on a df with respect to the chain angle

A couple of flat plates could be bolted just behind the bottom bracket shell and with a bit of clever-ness you could make a bolt on plate

or remove the BB assemble and get someone to mig/tig a tube onto the BB I believe the boom on that KMX is steel .

Atomic zombie is the website where most trike builders are found including me ,

FYI DNP make a freewheel unit that goes down to 11t but 44-11 is only a 80" top gear

 

[Falco Frank]

@Andrew1971 if needed, you have a framebuilder near you too:

http://arthurcaygillcycles.co.uk/framebuilding-and-renovations

 

[numbnuts]

I believe the boom on that KMX is steel

It's aluminum

 

[Andrew1971]

Yes the boom aluminum. Thank you Falco Frank i had no idea he was there
@voyager look's like i wil have to go that way. i will see what i can bodge up
Andrew

 

[voyager]

Just had a look at the trikes specification


Problem with alloy welding the front boom is the boom would need head treatment after tig welding so it would become an expensive piece of rework
personally I would go with a couple of steel plates and a tube welded via a spacer to one of the plates . as the whole assembly is not a stress point then you could get away with a bolt on plate - Don't forget to use a piece of tape or similar to insulate the dissimilar metals so electrolysis cannot start off any corrosion

regards emma

 

[ufkacbln]

Probably as (if not more) expensive

There are a number of "add on" dérailleur posts

This one is from Utah Trikes for the TerraTrike Rover

Could easily be fixed to the KMX