Guessing tubing type based on weight
10-14-19, 09:31 AM
#1
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Guessing tubing type based on weight
I have a 1971 Lygie that I’m trying trying to figure out what the fork is made of. The frame is stickered as a 531 butted frame so I’m assuming that means the main triangle only, but there’s no markings on the fork. It weighs 812g with a crown race.
Based on weights of two other bikes that I’ve had torn apart I’m guessing the fork is also a 531.
Here’s my data: my 74 Raleigh International has a 836g fork and it’s 531 and my 76 Bruce Gordon which is unmarked but I’m assuming is 531 because there’s no rifling inside the steerer tube is 748 g.
So since it falls between those two is that a reasonable assumption? I ask because I may add the sticker as I’m in a repaint mode.
I would love to know what the BG is made of bit I have no clues. Has a 27.0 seat post. Frame weighs 2027g and the size is 23 inch.
Ozzie
Based on weights of two other bikes that I’ve had torn apart I’m guessing the fork is also a 531.
Here’s my data: my 74 Raleigh International has a 836g fork and it’s 531 and my 76 Bruce Gordon which is unmarked but I’m assuming is 531 because there’s no rifling inside the steerer tube is 748 g.
So since it falls between those two is that a reasonable assumption? I ask because I may add the sticker as I’m in a repaint mode.
I would love to know what the BG is made of bit I have no clues. Has a 27.0 seat post. Frame weighs 2027g and the size is 23 inch.
Ozzie
10-14-19, 09:50 AM
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Not sure you'd be able to tell without markings on the fork or steerer identifying it.
With a difference of 60 or 70 grams between your other forks, that could be chalked up to steerer length, dropouts, fork crown, shape and gage of the blades.
With a difference of 60 or 70 grams between your other forks, that could be chalked up to steerer length, dropouts, fork crown, shape and gage of the blades.
10-14-19, 09:56 AM
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You need to be comparing apples with apples. Steerer length will obviously affect things. I've got a running spreadsheet with the weights of the bare frames & forks I've stripped. Most of them are 56cm, so have similar length steerers.
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10-14-19, 11:33 AM
#4
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The Lygie and Bruce Gordon are both 23 and the International is 22.5. I guess I may never know. None of the photos I can find have a fork decal.
10-14-19, 12:31 PM
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Sometimes you can find identifying marks. Columbus steer tubes are rifled and have a dove stamped on the tube. Reynolds 531 steer tubes are stamped REYNOLDS 531 BUTTED. But sometimes these marks are lost when the tubes are trimmed.
10-14-19, 02:36 PM
#7
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Fork is out. Only stamping at all is a “23”. Oh well. I was hoping for guilt by association.
10-14-19, 03:02 PM
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obucler-
It's likely 531. I had a 531 Raleigh/Carlton Grand Sport fork with forged Vagner crown and stamped dropouts. It weighed 870 gm sized for a 23.5 inch frame and your fork weight is well below that which is not surprising since the GS was a touring spec design with a likely heavier gauge.
It's likely 531. I had a 531 Raleigh/Carlton Grand Sport fork with forged Vagner crown and stamped dropouts. It weighed 870 gm sized for a 23.5 inch frame and your fork weight is well below that which is not surprising since the GS was a touring spec design with a likely heavier gauge.
