The Chameleon from year 2003-current requires a 34.9mm top swing, top pull derailleur. Older models (without the integrated disk brake mount) require a 31.8 top swing, top pull.
The current Chameleon (2003-current) uses a 30.9mm seatpost. Older Chameleons used a 27.2mm post. The post must always be inserted a minimum of 4”.
For simplicity’s sake, we didn’t design the Chameleon for single speed usage with disk brakes. Trying to get that to work properly involves either a sliding disk mount or an eccentric bottom bracket shell, which would complicate set-up on multi-speed bikes. We definitely have seen it work, but it takes a lot of trial and error to find a gear combination that keeps the chain tight enough. You need to use the dropout inserts if you are running disks, otherwise the rotor will not line up properly with the brake pads.
The brake cable guides on the Chameleon accept both cable stops and hydraulic lines. Use the black aluminum inserts for cable actuated brakes, and the grey plastic inserts are for hydraulic lines or continuous housing.
We do have a Chameleon disc brake adapter option that bolts directly to 2000-02 model Chameleons, or 1998/99 Chameleons with some minor frame modifications. The mount is for the "International Standard" hole pattern. The Suggested Retail Price for the disc mount is $40, and it is available for purchase on our online store.
Please contact us for instructions if you would like to retrofit your 98-99 model Chameleon.
It really depends a lot on the crank manufacturer. The Chameleon (like 95% of the bikes out there) requires a 47.5-50mm chainline. That is a measurement from the center of the BB shell to the middle ring. All of the new external bearing cranksets should work- just follow the manufacturer instructions for set-up on a 68mm BB shell. Old XTR cranks (before the external bearings) should use a 116. Most ISIS cranks should use a 113. Older XT cranks (2002-2003) use a 113. LX cranks from’03- '04 use a 121mm. As always, call your crank manufacturer if you have doubts- just tell them you need a 50mm chainline. ALWAYS buy for a 68mm shell.