Strange MTB spotted in the wilds of North Jersey

[AndyA]

This bike is on Craigslist in North Jersey. Has anyone ever seen an individual of this species? Is it naturally occurring or is it the result of secret experiments? Is there any advantage to moving the chainstays up from the bottom bracket? Why can't I stop looking at it?

 

[SKPC]

The elevated chainstay design eliminated "chain slap" noise of a bouncing-around chain hitting the stay. A few makers in the 90's I think through 2000 made them, both rigid and full suspension designs. Re-painted Nishiki maybe? Ovalized downtube should determine maker.

 

[AndyA]

SKPC:
Thanks for the schooling. I Googled "elevated chain stay" and found out, like you said, it was a thing in the 90's. Another advantage of the setup is that you can drop the chain without breaking it. The subject bike seems to be a Roadmaster Techno-Trac. Also found a Youtube item illustrating a possible problem with the design (link below).

 

[SKPC]

I lusted for some time over the SC Heckler, which was 10-15 years ago a very rideable, single pivot FS bike. Long travel & not many bad traits that plagued FS designs. One of the better Elevated stay bikes that used fast-improving air shock technology that rode better than most single pivot bikes of the time. Still relevant today. The Chinese Junk bike that busted was scary!

 

[wheelbender6]

I wanted one of these Mrazeks for a long time, but I am too old for serious mountain biking now.

 

[fattyre]

I wanted a Haro Extreme so bad back in the day. Such funny looking bikes now that MTBs have evolved to what really works.

 

[all riders]

I used to run into these used all the time. The elevated chainstay also get the relatively small tubing out of harms way

 

[Mr. Monkeyarms]

Wasn't the elevated chainstay a Cunningham design?

I wanted a Haro Extreme so bad back in the day. Such funny looking bikes now that MTBs have evolved to what really works.
View attachment 1231976

View attachment 1231977

(I actually have an excellent condition Impulse Comp in storage. Same color too. Has awesome handle bars!)

 

[cyclingday]

Mantis made a very nice looking elevated chainstay design that had an entire rear subframe that was replaceable.
The concept for the design was to eliminate a perceived problem called, “chain suck“
In the early days of Mountain Biking, the use of a third “granny gear” chainring was causing the chain to ride up on the inner ring and jam between the frame and tire, after the chain gummed up with dirt and grime.
It turned out to be a problem that had more to do, with a poorly maintained bicycle, than of the design itself, so the elevated chainstay was a short lived fad, until the advent of the full suspension mountain bike.
Then the design made a dramatic comeback, as this proved to be one of the most efficient ways to pivot the swing arm.

 

[SKPC]

Yes, it came back Marty, but with caveats. As you know, 90's into 2000's single-pivot full suspension bikes exhibited some terrible traits. One was "brake jack", where the suspension stopped working or was frozen out when you hit the rear brake. Chain stretch and loss was another you could feel while pedaling the design. "Bobbing", or bouncing up and down while pedaling was another. The shock technology then was in it's infancy when these FS single-pivot designs were used, elevated stay or not. These traits nearly doomed the Elevated stay Full-Sus designs, but wait!
Fox shocks then ramped up the sophistication of their new air/coil shock designs using Formula-1 platform shock technologies. This allowed the bad traits of a single-pivot design to be "lessened". Today, the single-pivot full suspension mtb designs are still around because of this and other small changes to it, (elevated and not) but they are still a bit less advanced compared to the DW link/VP link and other feedback-free designs with multiple pivots and linkages. Trek still hangs on with their nice carbon, single-pivot frame that I would love to ride. The single-pivot swingarm is not dead and may never be. This may also be true with the elevated chain stay design as well...