Flattened Oval Top Tube ? 1986 ALAN Record
#1
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
Flattened Oval Top Tube ? 1986 ALAN Record
I noticed that my new-to-me 1986 ALAN Record has a slightly flattened oval top tube.
At the front and rear of the bike, where it fits into the seat post lug and head tube lug the top tube is round, and about 1 inch in diameter.
In the middle of the tube the top tube is slightly flattened, and measures about an inch and an eighth wide ( looking down from the top ) and about seven eighths of an inch ( when seen from the side ) at the middle cable guide.
The way the reflected light hits the frame makes the difference obvious. (See picture).
I'm wondering if this is of structural benefit and if it is why isn'y it a more common design feature ?
Bink
At the front and rear of the bike, where it fits into the seat post lug and head tube lug the top tube is round, and about 1 inch in diameter.
In the middle of the tube the top tube is slightly flattened, and measures about an inch and an eighth wide ( looking down from the top ) and about seven eighths of an inch ( when seen from the side ) at the middle cable guide.
The way the reflected light hits the frame makes the difference obvious. (See picture).
I'm wondering if this is of structural benefit and if it is why isn'y it a more common design feature ?
Bink
#2
Senior Member
Join Date: Jul 2002
Location: Sacramento, California, USA
Posts: 40,865
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 2952 Post(s)
Liked 3,106 Times
in
1,417 Posts
I don't know if it provides any structural benefits, but my cyclocross bike has an ovalized top tube that makes it a bit more comfortable when shouldering.
#3
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
Just curious.
Bink
#4
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,084
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4205 Post(s)
Liked 3,866 Times
in
2,312 Posts
Alan did offer a CX frame which, IIRC, had a flattened top tube. perhaps for some reason that model's TT was used on the OP's frame. Andy
__________________
AndrewRStewart
AndrewRStewart
#5
Senior Member
Join Date: Mar 2019
Posts: 1,606
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 581 Post(s)
Liked 921 Times
in
518 Posts
There haven't been many aluminum frames made with round cross-section tubes for a long time. Most new bikes have some type of 3D or complicated profile done by 'hydroforming', while old bikes always started with round tubes, and flattening along one axis was the primary strategy to 'tune' tubes for whatever purpose. By the early 90s, most chromoly bikes had similar shaping done to their downtubes, usually flattened width-wise at the head tube and height-wise at the bottom bracket.
Likes For ClydeClydeson:
#6
Senior Member
Join Date: Feb 2012
Location: Rochester, NY
Posts: 18,084
Bikes: Stewart S&S coupled sport tourer, Stewart Sunday light, Stewart Commuting, Stewart Touring, Co Motion Tandem, Stewart 3-Spd, Stewart Track, Fuji Finest, Mongoose Tomac ATB, GT Bravado ATB, JCP Folder, Stewart 650B ATB
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4205 Post(s)
Liked 3,866 Times
in
2,312 Posts
"I'm wondering if this is of structural benefit and if it is why isn'y it a more common design feature" Bink
In theory a non round tube can have greater bending resistance in the long axis, of an ovalized section of tube, and less so along the short or less wide axis. But remember that the main triangle tubes see a lot of twisting forces, not so much mere bending. The torsional stiffness of an ovalized tube is substantially limited to what a virtual tube would have that has a diameter equal to the shorter axis. (Put another way if a tube is ovalized so it's small axis is half that of the starting round diameter the rotational stiffness will be about 1/4 of the original round tube had. Torsional stiffness has a geometrical relationship with diameter). So ovalizing a main triangle tube has more drawbacks then only the added cost.
Now another reason to ovalize at the ends is to be able to use a larger diameter tube then would fully contact the joining tube. Ovalizing the large tube will allow the joint (welded or brazed)to have complete tube to tube contact and increase the amount of the weld or fillet. As example is a 1.25" top rube joined to a 1.125" seat tube. The sides (or ears of the miter) of the TT will not be touching the ST. By ovalizing the TT vertically the entire TT miter will touch the ST and thus have theoretically more weld/fillet length.
But in real life the differences are fairly minor and the actual welding/filleting skills can be far larger an amount of "change".
It's my opinion that many shaping of tubes is more about branding and marketing then realized strength or stiffness gains. Andy
In theory a non round tube can have greater bending resistance in the long axis, of an ovalized section of tube, and less so along the short or less wide axis. But remember that the main triangle tubes see a lot of twisting forces, not so much mere bending. The torsional stiffness of an ovalized tube is substantially limited to what a virtual tube would have that has a diameter equal to the shorter axis. (Put another way if a tube is ovalized so it's small axis is half that of the starting round diameter the rotational stiffness will be about 1/4 of the original round tube had. Torsional stiffness has a geometrical relationship with diameter). So ovalizing a main triangle tube has more drawbacks then only the added cost.
Now another reason to ovalize at the ends is to be able to use a larger diameter tube then would fully contact the joining tube. Ovalizing the large tube will allow the joint (welded or brazed)to have complete tube to tube contact and increase the amount of the weld or fillet. As example is a 1.25" top rube joined to a 1.125" seat tube. The sides (or ears of the miter) of the TT will not be touching the ST. By ovalizing the TT vertically the entire TT miter will touch the ST and thus have theoretically more weld/fillet length.
But in real life the differences are fairly minor and the actual welding/filleting skills can be far larger an amount of "change".
It's my opinion that many shaping of tubes is more about branding and marketing then realized strength or stiffness gains. Andy
__________________
AndrewRStewart
AndrewRStewart
#7
Senior Member
Join Date: Jul 2002
Location: Sacramento, California, USA
Posts: 40,865
Bikes: Specialized Tarmac, Canyon Exceed, Specialized Transition, Ellsworth Roots, Ridley Excalibur
Mentioned: 68 Post(s)
Tagged: 0 Thread(s)
Quoted: 2952 Post(s)
Liked 3,106 Times
in
1,417 Posts
There haven't been many aluminum frames made with round cross-section tubes for a long time. Most new bikes have some type of 3D or complicated profile done by 'hydroforming', while old bikes always started with round tubes, and flattening along one axis was the primary strategy to 'tune' tubes for whatever purpose. By the early 90s, most chromoly bikes had similar shaping done to their downtubes, usually flattened width-wise at the head tube and height-wise at the bottom bracket.
#8
Senior Member
Join Date: Aug 2009
Posts: 2,394
Mentioned: 14 Post(s)
Tagged: 0 Thread(s)
Quoted: 1562 Post(s)
Liked 1,734 Times
in
974 Posts
Some bikes in the 80's had tubes which were ovalized in the middle for aerodynamics. Like the Nishiki Aero II I have:
But they were ovalized in the horizontal direction. ie. it's skinny in the horizontal direction and tall in the vertical direction. Your ALAN looks to be opposite of that.
Are you sure it didn't just get squished by a careless mechanic on the bike stand? Are there any other ALAN frames like that?
But they were ovalized in the horizontal direction. ie. it's skinny in the horizontal direction and tall in the vertical direction. Your ALAN looks to be opposite of that.
Are you sure it didn't just get squished by a careless mechanic on the bike stand? Are there any other ALAN frames like that?
#9
Senior Member
Join Date: Dec 2007
Location: San Jose, California
Posts: 3,504
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 145 Post(s)
Likes: 0
Liked 35 Times
in
30 Posts
I noticed that my new-to-me 1986 ALAN Record has a slightly flattened oval top tube.
At the front and rear of the bike, where it fits into the seat post lug and head tube lug the top tube is round, and about 1 inch in diameter.
In the middle of the tube the top tube is slightly flattened, and measures about an inch and an eighth wide ( looking down from the top ) and about seven eighths of an inch ( when seen from the side ) at the middle cable guide.
The way the reflected light hits the frame makes the difference obvious. (See picture).
I'm wondering if this is of structural benefit and if it is why isn'y it a more common design feature ?
Bink
At the front and rear of the bike, where it fits into the seat post lug and head tube lug the top tube is round, and about 1 inch in diameter.
In the middle of the tube the top tube is slightly flattened, and measures about an inch and an eighth wide ( looking down from the top ) and about seven eighths of an inch ( when seen from the side ) at the middle cable guide.
The way the reflected light hits the frame makes the difference obvious. (See picture).
I'm wondering if this is of structural benefit and if it is why isn'y it a more common design feature ?
Bink
Just curious...
=8-|
__________________
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
5000+ wheels built since 1984...
Disclaimer:
1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:
Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
#10
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
I cannot imagine a bike mechanic reefing down on ANY kind of a bike stand clamp with enough force to flatten a bike tube.
Anyway, I found pictures of other ALAN Record frames, as new, on the internet.
Some, but not all, appear to have a flattened top tube. See attached picture from a catalog of some sort.
Bink
Likes For Binky:
#11
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
Wow !! Now I'm curious too.
How would I be able to tell ?
Its a ALAN Record made in May, 1986 if that helps.
I traded a Raleigh Grand Prix for this bike to a guy who bought the ALAN second hand off a guy on CraigsList, so the history is a mystery to me.
How can i tell if the forks are, as you call them, the "original recall forks" ?
Does the fork crown appear to be any different from the forks they replaced ?
Bink
#12
Senior Member
Join Date: Jan 2013
Posts: 2,679
Bikes: too many sparkly Italians, some sweet Americans and a couple interesting Japanese
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 569 Post(s)
Liked 582 Times
in
409 Posts
In the old days Park Tools and other stands had levers that could get some serious torque and at a spring setting that worked fine on a gas pipe 1" top tube but could crush a carbon top tube especially a larger diameter if you did not back off the spring tension. To have smashed that Alan tube so beautifully the mechanic would have to have been an artist.
#13
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
I just sent off an email to ALAN in Italy with the model and date of manufacture of my bike (May, 1986) and a picture of the frame with a request for information about possible issues or recalls.
Its Sunday so it may be a while before I hear back from them... but I will let you know what (and if) they reply.
I also scoured the internet and the Bike Forums archives to see it it has been an issue. I could find nothing there of note.
What info do you have to share ?
Back soon - I'm off for a ride on the ALAN before it gets too hot.
Bink
Its Sunday so it may be a while before I hear back from them... but I will let you know what (and if) they reply.
I also scoured the internet and the Bike Forums archives to see it it has been an issue. I could find nothing there of note.
What info do you have to share ?
Back soon - I'm off for a ride on the ALAN before it gets too hot.
Bink
Likes For Binky:
#14
Senior Member
I bought an Alan frame, new, back in '88. I don't know when it was manufactured (frame is long gone...cracked seat lug). Anyhow. the top tube was definitely round. I noticed in the pic from the catalogue that the frame shown only has two cable guides on the top tube. Your frame has three and so did mine. Wondering if that matters? As far as the recalled fork, I was told by other riders that the forks with alloy steerers were prone to fail. This was hearsay and I never got any real proof. BTW. Mine had an alloy steerer and I rode it for 45,000+ miles before I noticed the seat lug crack.
#15
Senior Member
I just sent off an email to ALAN in Italy with the model and date of manufacture of my bike (May, 1986) and a picture of the frame with a request for information about possible issues or recalls.
Its Sunday so it may be a while before I hear back from them... but I will let you know what (and if) they reply.
I also scoured the internet and the Bike Forums archives to see it it has been an issue. I could find nothing there of note.
What info do you have to share ?
Back soon - I'm off for a ride on the ALAN before it gets too hot.
Bink
Its Sunday so it may be a while before I hear back from them... but I will let you know what (and if) they reply.
I also scoured the internet and the Bike Forums archives to see it it has been an issue. I could find nothing there of note.
What info do you have to share ?
Back soon - I'm off for a ride on the ALAN before it gets too hot.
Bink
I just found an Alan like yours, “Record” model, flattened top tube.
Seller lists it as 130mm between dropouts.
I am wondering what your frame measures? 1986 seems early for 130mm, right?
Best,
Robyn
#16
Senior Member
Thread Starter
Join Date: Mar 2013
Location: Southern Ontario, Canada
Posts: 873
Bikes: Too, too many....
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 125 Post(s)
Likes: 0
Liked 130 Times
in
57 Posts
Bink
Likes For Binky:
#17
Senior Member
Join Date: Jan 2019
Location: Netherlands
Posts: 669
Bikes: Especialy Alan, but also Empella, Cascarsi, Gazelle, Bianchi, CJV, Sirocco, Berkers etcetera
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 188 Post(s)
Liked 997 Times
in
355 Posts
I got a Super Record, a Record and multiple CX with flattened top tubes.
See part of a catalog from 1983 on the so-called model Sprint (the same as the Super Record) those days.
And far as I know is trouble/recall with Alan frames a myth. The real story was about the Viscount/Lambert fork.
The fork on Binky's Record is the correct fork.
See part of a catalog from 1983 on the so-called model Sprint (the same as the Super Record) those days.
And far as I know is trouble/recall with Alan frames a myth. The real story was about the Viscount/Lambert fork.
The fork on Binky's Record is the correct fork.
#18
Senior Member
Likes For Surfer77:
#19
I'm good to go!
Join Date: Jul 2017
Location: Mississippi
Posts: 14,988
Bikes: Tarmac Disc Comp Di2 - 2020
Mentioned: 51 Post(s)
Tagged: 0 Thread(s)
Quoted: 6193 Post(s)
Liked 4,810 Times
in
3,318 Posts
Might be the builder/designer was more interested in what they thought was creating a more aesthetic look and appeal for their customers than a truly beneficial structural design or aerodynamic consideration.
Likes For Iride01:
#21
Senior Member
Likes For fabiofarelli:
#23
Senior Member
-Robyn
Likes For Surfer77:
#24
Senior Member
-Robyn
Likes For Surfer77:
#25
Senior Member
Join Date: Jan 2019
Location: Netherlands
Posts: 669
Bikes: Especialy Alan, but also Empella, Cascarsi, Gazelle, Bianchi, CJV, Sirocco, Berkers etcetera
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 188 Post(s)
Liked 997 Times
in
355 Posts
Drenthe is nice, since a few years we do a ride there, small group, great fun. Nearby the Vam-berg.
Likes For fabiofarelli: