SUPER RARE MYSTERY REAR MECH, ANYONE KNOW WHAT IT IS?

Ok so it is probably not rare, but i have never seen one.

The mech came on an Orbit Frontier i picked up recently, from a pic of a complete Orbit i found i think it is original to the bike.

The series number is RD M531, but when i google this i get 9 speed and modernish deore.

The front mech is FD Z206 which is a road and atb front mech from 84-86.

the mech appears to be a specific atb/mtb style mech, not a road mech. but if it is 84-86 and for mtb i would have thought it would be on mombat.

mech is very well made , up there with slightly later lx and dx and not far of its contemporary xt i reckon, interesting spring set up too,


so has anyone got an info on this please? bikes it came on, where it fits in shimanos line up, year etc. i appreciate it is not a full gruppo

oh and the pic that makes me think it is original.

and my bike

I think they were sold as simply shimano sis mechs and weren't that high up the food chain, about lx as you mentioned, but I could be wrong. Fairly sure a friend had a carerra road bike that came with them too.

I think that was what they referred to as "Z" series, introduced in about '86, and only 1 step down from XT in those days. I have a set waiting to go on my Frontier.

It is on Mombat!

Part of the first wave of SIS stuff as above - it went with this era of chainset:



1987 Saracen wearing the same mechs

Cheers folks, got a bit of a lead from Harrycrumb

apparently it is closely related to shimanos "light action series"

http://www.disraeligears.co.uk/Site/Shi ... GS%29.html

they released it in 86 but kept it a bit quiet after suntours positron bombed, not sure if they wanted to see if it would work or how it would be recieved

http://www.disraeligears.co.uk/Site/Shi ... an_21.html

did a bit more digging on disraeli and then found this

http://www.disraeligears.co.uk/Site/Shi ... an_24.html

my mech, and it is atb off road specific. released in december 86.

which suggests my bike is perhaps 87.

I really didnt think Orbit or bikes made in the uk would be funky flouro colours this early as i always thought the uk lagged behind a bit and were less daring, obviously not given the fades on the two bikes above though

will post a build thread on her soon

It was probably one of the first Shimano slant parallelogram rear mechs that works all the way up to 9spd indexing. I have had a few but havent seen one in the flesh for a while.

so would you be happy saying my bike is 87 Mark? did you get flouro bikes this early in uk? or were orbit cutting edge.

when was the first flouro bike?

87 was the year of flouro, big surf and skate scene. Clothes, shoes, allsorts went flouro - I painted my Sony Walkman pink/ yellow to suit...

So glad you got the Orbit Charlie, I was a bit concerned that I might have messed things up by outing it.

I'll keep an eye out for that build thread .