Looking for French frame with high-ish bb
11-21-23, 04:17 AM
#1
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Looking for French frame with high-ish bb
Recently I measured the frame drop of some of the daily riders and the favourite one has quite a high bb; drop is about 65mm.
That frame is also small (52cm seat tube) and short (39cm wheelbase), but it's not that light: although metric tubing, the seatpost is 26mm, so it's not butted.
I think it's a Mercier because of some frame details, but it has no markings or decals that would help (seat lug says 75; I think that angle might also be part of why I like it).
It's built from bits - all I got was the bare frame with a BB in it - the brand of the BB won't pass the auto-censor (F A G sans les espaces).
I have some nice french bits to put on a frame, and they'd suit a better one.
I want it to go like this one.
What french bikes had such geometry?
Have? - got one? measure it for me please...
(ob. pic
That frame is also small (52cm seat tube) and short (39cm wheelbase), but it's not that light: although metric tubing, the seatpost is 26mm, so it's not butted.
I think it's a Mercier because of some frame details, but it has no markings or decals that would help (seat lug says 75; I think that angle might also be part of why I like it).
It's built from bits - all I got was the bare frame with a BB in it - the brand of the BB won't pass the auto-censor (F A G sans les espaces).
I have some nice french bits to put on a frame, and they'd suit a better one.
I want it to go like this one.
What french bikes had such geometry?
Have? - got one? measure it for me please...
(ob. pic
11-21-23, 07:01 AM
#2
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You may want to spend some time here: find and compare bike geometry
Likes For non-fixie:
11-21-23, 07:46 AM
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Gitane for a while with small frames adjusted geometry this way.
steep seat tube angle was a bit of a cheat unless you have size 8 or under shoes and shorter femurs.
a minimal drop bottom bracket was also to achieve a dimension unless you were a criterium racer and wanted to pedal through the corners.
‘I had a bike like that, with 167.5 cranks I could pedal through corners that my competitors could only strike a pedal and sometimes skip a rear wheel.
steep seat tube angle was a bit of a cheat unless you have size 8 or under shoes and shorter femurs.
a minimal drop bottom bracket was also to achieve a dimension unless you were a criterium racer and wanted to pedal through the corners.
‘I had a bike like that, with 167.5 cranks I could pedal through corners that my competitors could only strike a pedal and sometimes skip a rear wheel.
11-21-23, 09:11 AM
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High BB's seem to be a habit with smaller French bikes, that's how they could shorten the seat tube (but not the standover, which wasn't much of a concern to them anyway; see "French fit") to fit a smaller rider while keeping the toptube horizontal.
The bicycle in the picture is also made by an unknown manufacturer with Camus 779 tubing decals. With 28-622 rubber, the widest it'll fit (not in picture), the BB spindle is roughly 30 cm off the ground, over 1" or 25,4mm more than is common with roadbikes of the 70's. (See: Dave Moulton's Blog - Dave Moulton's Bike Blog - Bottom Bracket Height)
In this case the cantilever brakes suggest it might be a randonneuse, intended for riding fast through the French countryside, which would in part also explain a higher bottom bracket. Much like an early CX bike!
The bicycle in the picture is also made by an unknown manufacturer with Camus 779 tubing decals. With 28-622 rubber, the widest it'll fit (not in picture), the BB spindle is roughly 30 cm off the ground, over 1" or 25,4mm more than is common with roadbikes of the 70's. (See: Dave Moulton's Blog - Dave Moulton's Bike Blog - Bottom Bracket Height)
In this case the cantilever brakes suggest it might be a randonneuse, intended for riding fast through the French countryside, which would in part also explain a higher bottom bracket. Much like an early CX bike!
11-21-23, 10:43 AM
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You may want to spend some time here: find and compare bike geometry
11-21-23, 11:21 AM
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High BB's seem to be a habit with smaller French bikes, that's how they could shorten the seat tube (but not the standover, which wasn't much of a concern to them anyway; see "French fit") to fit a smaller rider while keeping the toptube horizontal.
The bicycle in the picture is also made by an unknown manufacturer with Camus 779 tubing decals. With 28-622 rubber, the widest it'll fit (not in picture), the BB spindle is roughly 30 cm off the ground, over 1" or 25,4mm more than is common with roadbikes of the 70's. (See: Dave Moulton's Blog - Dave Moulton's Bike Blog - Bottom Bracket Height)
In this case the cantilever brakes suggest it might be a randonneuse, intended for riding fast through the French countryside, which would in part also explain a higher bottom bracket. Much like an early CX bike!
The bicycle in the picture is also made by an unknown manufacturer with Camus 779 tubing decals. With 28-622 rubber, the widest it'll fit (not in picture), the BB spindle is roughly 30 cm off the ground, over 1" or 25,4mm more than is common with roadbikes of the 70's. (See: Dave Moulton's Blog - Dave Moulton's Bike Blog - Bottom Bracket Height)
In this case the cantilever brakes suggest it might be a randonneuse, intended for riding fast through the French countryside, which would in part also explain a higher bottom bracket. Much like an early CX bike!
It looks to me like the designer of this bike had fix gear use on the road in mind from the beginning. I like!
11-21-23, 11:50 AM
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The available data varies per bike, depending on the source. I have been using this site to compare my own findings. Examples of BB drop data I've found on this site:
57 and 58cm René Herse (2007, 2009) : 80 mm BB drop
57cm Alex Singer (2003) : 75 mm BB drop
65cm Raleigh Grand Prix (1974) : 55 mm BB drop
57 and 58cm René Herse (2007, 2009) : 80 mm BB drop
57cm Alex Singer (2003) : 75 mm BB drop
65cm Raleigh Grand Prix (1974) : 55 mm BB drop
11-21-23, 01:20 PM
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On a smaller frame, I would go with more BB drop as I often also set them up with 165 mm cranks.
Builders like Richard Sachs have mentioned 8cm of drop as a good dimension. At the time he did not match to frame size.
way back when I read that from him I was surprised, I do disagree with Dave M that one does not feel the difference. I do think one adapts to a bike pretty fast.
I could make my Ultra Short Wheelbase Harry Quinn with an 11” high BB and WB of 37.25” ( it was British, imperial measures back then)
really go on a descent but I was young and fearless, tons of front overlap btw.
all these dimensions play a part of the whole.
I have noticed with Mercier - the top quality frames have more nuance in the geometry.
obtaining accurate dimension takeoffs are always a problem.
Builders like Richard Sachs have mentioned 8cm of drop as a good dimension. At the time he did not match to frame size.
way back when I read that from him I was surprised, I do disagree with Dave M that one does not feel the difference. I do think one adapts to a bike pretty fast.
I could make my Ultra Short Wheelbase Harry Quinn with an 11” high BB and WB of 37.25” ( it was British, imperial measures back then)
really go on a descent but I was young and fearless, tons of front overlap btw.
all these dimensions play a part of the whole.
I have noticed with Mercier - the top quality frames have more nuance in the geometry.
obtaining accurate dimension takeoffs are always a problem.
