What is it? 1980s Roadmaster? mtb with non-round top tube and downtube
07-04-21, 05:22 PM
#1
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What is it? 1980s Roadmaster? mtb with non-round top tube and downtube
what is it? the top tube is tear drop shaped with the blunt end pointed up.
The downtube is flattened vertically behind the head tube and horizontally at the bb.
Threaded bb.
mono-seat stay.
The previous owner had it powder coated long ago and could not remember the brand or model.
no trace of the serial number. Obscured by the new paint.
It's similar to a Roadmaster Techno Trac I had last (broken and scrapped out).
The downtube is flattened vertically behind the head tube and horizontally at the bb.
Threaded bb.
mono-seat stay.
The previous owner had it powder coated long ago and could not remember the brand or model.
no trace of the serial number. Obscured by the new paint.
It's similar to a Roadmaster Techno Trac I had last (broken and scrapped out).
07-05-21, 05:00 PM
#2
Bikes are okay, I guess.
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what is it? the top tube is tear drop shaped with the blunt end pointed up.
The downtube is flattened vertically behind the head tube and horizontally at the bb.
Threaded bb.
mono-seat stay.
The previous owner had it powder coated long ago and could not remember the brand or model.
no trace of the serial number. Obscured by the new paint.
It's similar to a Roadmaster Techno Trac I had last (broken and scrapped out).
The downtube is flattened vertically behind the head tube and horizontally at the bb.
Threaded bb.
mono-seat stay.
The previous owner had it powder coated long ago and could not remember the brand or model.
no trace of the serial number. Obscured by the new paint.
It's similar to a Roadmaster Techno Trac I had last (broken and scrapped out).
07-05-21, 05:14 PM
#3
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Outside of the weird down and top tube shapes, I'm not seeing any relationship between those two frames. That Technotrac has a weird curve in the seat tube and an extra tube linking the seat tube and the down tube. It also has a completely different angle on the chain stays. The red frame seems rather standard issue in comparison. Did anyone else use those non-round tubes?
07-06-21, 08:50 AM
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The top bike is a design often called an E Stay (elevated chain stay) and was popular for a time around the 1980's-1990's. An interesting design that allowed the chain to be completely removed but eventually they phased out as there was a problem with frame cracking. I have one made by Nishiki.
07-06-21, 09:50 AM
#5
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I wouldn't doubt that Sears would have their name on a Roadmaster.
07-11-21, 06:37 PM
#6
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the elevated chainstay was to help eliminate chain suck on mountain bikes. But so many frames broke due to poor construction. just welding or brazing the stays to the back of seat tube was the main problem. using longer stays that overlap the downtube was a stronger design.
I'm still looking for an elevated stay frameset with horizontal dropouts for a build project but have yet to find one.
I'm still looking for an elevated stay frameset with horizontal dropouts for a build project but have yet to find one.
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07-11-21, 10:56 PM
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Rickpaulos is right. The elevated chainstay was to eliminate chain suck. Don't know the brand.
