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Author Topic: Reproducing a CB frame in Aluminum?  (Read 3556 times)

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Offline P_Camps

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Reproducing a CB frame in Aluminum?
« on: February 17, 2011, 09:30:01 AM »
I understand the frames on our CB's are Steel frame.   

Aluminum Frame. can it be done/reproduced?  Has anybody ever done it.
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Offline Roach

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Re: Reproducing a CB frame in Aluminum?
« Reply #1 on: February 17, 2011, 09:33:14 AM »
sure it can be done any thing can be done with the right tools and know how. Have i seen it done no. but doesnt go to say that someone hasnt tried and just not recorded it. it sure would lighten things up. to keep the same styling it would probably need alot more gussets.
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Offline odiewan

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Re: Reproducing a CB frame in Aluminum?
« Reply #2 on: February 17, 2011, 10:42:28 AM »
The other thing that it would probably require is either thicker tube walls, larger OD tubes or both to get the right stiffness. But it does sound like a great idea.

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Offline Duke McDukiedook

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Re: Reproducing a CB frame in Aluminum?
« Reply #3 on: February 17, 2011, 12:20:42 PM »
If you are going to go to that trouble just do a repro in titanium, you wouldn't have to increase the diameter and it would be way stronger.
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Offline mlinder

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Re: Reproducing a CB frame in Aluminum?
« Reply #4 on: February 17, 2011, 12:43:57 PM »
You wouldn't want to build an aluminum replica of an old basket frame like ours.

Aluminum breaks, mild steel flexes. You'd need about 40% thicker alu to attain the same flex and yield properties of steel.

Steel also has higher energy absorption properties. Aluminums fatigue properties are much worse than steels.

This is why alu frames are designed completely differently than steel frames.
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Offline fatmatt650

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Re: Reproducing a CB frame in Aluminum?
« Reply #5 on: February 17, 2011, 02:26:22 PM »
Oooohhh. A Ti frame would be very sexy. 8)
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Offline swellguy

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Re: Reproducing a CB frame in Aluminum?
« Reply #6 on: February 17, 2011, 10:13:26 PM »
4130 chromoloy would be the ticket.
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Offline xedge4lifex

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Re: Reproducing a CB frame in Aluminum?
« Reply #7 on: February 18, 2011, 12:23:42 AM »
Quote from: swellguy on February 17, 2011, 10:13:26 PM
4130 chromoloy would be the ticket.
+1

i went into researching this last year for a couple months, and it would take ALOT of work. im sure one of the guys on the forum knows. even the big boy vintage frames cb750s kz900s probably dont weigh more than what like 50 pounds? my buddy raced bmx for about 12 years and had a huge collection of frames. the carbon fiber frames had these chromoly gussets to connect the tubes visualize a T fitting if you will. and that frame probably weighed about 5 pounds? it would take some serious thinking to build a frame out of carbon fiber tubing and those gussets, buts you would be looking at like a 15 pound frame. swellguy has it chromoly will be the lightest, and give you that shiny look to get all the honeys
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Offline Duke McDukiedook

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Re: Reproducing a CB frame in Aluminum?
« Reply #8 on: February 18, 2011, 11:51:28 AM »
Titanium would be lighter, I think swell is more concerned about cost.
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Offline P_Camps

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Re: Reproducing a CB frame in Aluminum?
« Reply #9 on: February 19, 2011, 08:42:52 AM »
a 15 pound frame??  that would be bananas.   

CMON SCIENTISTS OF SOHC4 BUILD THY FRAME!! ;D ;) ;D ;)
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Offline FunJimmy

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Re: Reproducing a CB frame in Aluminum?
« Reply #10 on: February 19, 2011, 08:59:23 AM »
Quote from: Industrial-sized Dukiedook on February 17, 2011, 12:20:42 PM
If you are going to go to that trouble just do a repro in titanium, you wouldn't have to increase the diameter and it would be way stronger.


A titanium replica frame would be a noodle.
Ya, titanium is strong and light, but it sure isn't known for it's stiffness.
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Re: Reproducing a CB frame in Aluminum?
« Reply #11 on: February 19, 2011, 09:36:03 AM »
why do this to this old bikes..i like them like the are..dinasaures from the 70" dont hurt them.save them
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Offline Tim2005

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Re: Reproducing a CB frame in Aluminum?
« Reply #12 on: February 19, 2011, 09:54:16 AM »
Quote from: P_Camps on February 19, 2011, 08:42:52 AM
a 15 pound frame??  that would be bananas.   

CMON SCIENTISTS OF SOHC4 BUILD THY FRAME!! ;D ;) ;D ;)

You need to find yourself a Seeley frame, it's not far off that at all: "the Seeley frame, complete with rear swingarm only weighs 26.45 lb (12 kg)" from http://www.satanicmechanic.org/seeley.shtml
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alocker

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Re: Reproducing a CB frame in Aluminum?
« Reply #13 on: February 19, 2011, 10:23:46 AM »
Send your forks, engine, and swingarm to Harris or Spondon and they will probably make you one. 
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Offline malcolmgb

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Re: Reproducing a CB frame in Aluminum?
« Reply #14 on: February 19, 2011, 10:43:10 AM »
Take a look at Rick Denoon's home built frame, also from Canada, not aluminium but certainly lighter and more modern looking.

http://www.denoonsp.com/
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Offline Duke McDukiedook

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Re: Reproducing a CB frame in Aluminum?
« Reply #15 on: February 19, 2011, 10:55:18 AM »
Quote from: FunJimmy on February 19, 2011, 08:59:23 AM
Quote from: Industrial-sized Dukiedook on February 17, 2011, 12:20:42 PM
If you are going to go to that trouble just do a repro in titanium, you wouldn't have to increase the diameter and it would be way stronger.


A titanium replica frame would be a noodle.
Ya, titanium is strong and light, but it sure isn't known for it's stiffness.

Damn, didn't know Ti had 1/2 the stiffness of steel. Makes me want to rethink about possibly getting that Mootour bike I have been wanting for a while now.

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Offline fatmatt650

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Re: Reproducing a CB frame in Aluminum?
« Reply #16 on: February 19, 2011, 11:45:29 AM »
Get the Moots! I guarantee you that frame is NOT a noodle. Look at the tube size. 2 tubes of different materials w/ the same dimensions will have different properties. That's why a Ti framed bike (or aluminum) uses fatter diameter tubes w/ thinner wall thickness. The manufacturer tweaks his tubesets to get the desired flex where he wants it.

P.S. Check out the super sexy ti spring. They don't need as many coils to get the same amount of flex as steel because pond for pound, ti is flexier. At least, that's what years of geeking out over mountain bike magazines teaches me.  ;)
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Offline Retro Rocket

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Re: Reproducing a CB frame in Aluminum?
« Reply #17 on: February 19, 2011, 02:10:10 PM »
Quote from: swellguy on February 17, 2011, 10:13:26 PM
4130 chromoloy would be the ticket.

That would be the way to go...... ;)

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Offline bwaller

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Re: Reproducing a CB frame in Aluminum?
« Reply #18 on: February 19, 2011, 02:43:03 PM »
Don't forget this is basically what Tintop will do. Recreating a chromoly chassis for a 750 originally done back in the seventies by Denis Curtis cmrracingproducts.com. Denis is still at it & I can tell you he is a craftsman.

I'm sure he would gladly build a frame for anyone here, and then why not an alloy fuel tank to top it off.  ;D
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Offline Tintop

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Re: Reproducing a CB frame in Aluminum?
« Reply #19 on: February 19, 2011, 04:08:22 PM »
Quote from: bwaller on February 19, 2011, 02:43:03 PM
Don't forget this is basically what Tintop will do. Recreating a chromoly chassis for a 750 originally done back in the seventies by Denis Curtis cmrracingproducts.com. Denis is still at it & I can tell you he is a craftsman.

I'm sure he would gladly build a frame for anyone here, and then why not an alloy fuel tank to top it off.  ;D

Actually he will be starting on the frame for my 550 racer (& 2nd for a 750) mid March.  Have toyed with the idea of doing the 750 frame in SS.
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Offline socalenduro

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Re: Reproducing a CB frame in Aluminum?
« Reply #20 on: February 19, 2011, 05:36:17 PM »
Quote from: Industrial-sized Dukiedook on February 19, 2011, 10:55:18 AM
Quote from: FunJimmy on February 19, 2011, 08:59:23 AM
Quote from: Industrial-sized Dukiedook on February 17, 2011, 12:20:42 PM
If you are going to go to that trouble just do a repro in titanium, you wouldn't have to increase the diameter and it would be way stronger.


A titanium replica frame would be a noodle.
Ya, titanium is strong and light, but it sure isn't known for it's stiffness.

Damn, didn't know Ti had 1/2 the stiffness of steel. Makes me want to rethink about possibly getting that Mootour bike I have been wanting for a while now.



Thats alot of the point of a Ti bicycle...the light amount of flex will bring the frame alive and soften the ride. (if designed correctly) Moots makes some killer bikes. They know how to lay out the frame designs
Aluminum bikes are known for their stiffness, cro-mo is a bit more forgiving, and carbon fiber is just magic (can be ultra stiff or flex depending on how the fibers are laid and set up)
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Offline scottly

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Re: Reproducing a CB frame in Aluminum?
« Reply #21 on: February 19, 2011, 05:50:47 PM »
Quote from: Tim2005 on February 19, 2011, 09:54:16 AM
Quote from: P_Camps on February 19, 2011, 08:42:52 AM
a 15 pound frame??  that would be bananas.   

CMON SCIENTISTS OF SOHC4 BUILD THY FRAME!! ;D ;) ;D ;)

You need to find yourself a Seeley frame, it's not far off that at all: "the Seeley frame, complete with rear swingarm only weighs 26.45 lb (12 kg)" from http://www.satanicmechanic.org/seeley.shtml

I've got one, and I'm keeping it!!! ;D
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