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MGB Lightweight MGB Cross Member
- Thread starter Steve_S
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tony barnhill
Great Pumpkin - R.I.P
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Stock beam=28lbs:
Lightened beam, lower spring perches & A-arms =23 lbs:
Total weight loss = 5 pounds.
Lightened beam, lower spring perches & A-arms =23 lbs:
Total weight loss = 5 pounds.
tony barnhill
Great Pumpkin - R.I.P
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Hang on - lemme go back to my notes....
Stock beam = 28lbs
Lightened beam = 26lbs
2lbs difference
A-arms & spring perches lightened, brake dust covers removed & drilled/slotted rotors installed = 3lbs lighter
hubs turned down 5/8" to lighten = 1/2lb
Total = 5-1/2lbs lighter
Stock beam = 28lbs
Lightened beam = 26lbs
2lbs difference
A-arms & spring perches lightened, brake dust covers removed & drilled/slotted rotors installed = 3lbs lighter
hubs turned down 5/8" to lighten = 1/2lb
Total = 5-1/2lbs lighter
OP
Steve_S
Yoda
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Ok, the 2 lbs is what I was looking for. I had to move a bare cross member around tonight so I weighed it just for fun, then wondered how much weight would be lost by drilling it out. Like I said though, just curiosity. I got 28 pounds on a bathroom scale by weighing myself with and without it.
"hubs turned down 5/8""
You mean the outer diameter? I haven't heard of anyone doing that one before!
"hubs turned down 5/8""
You mean the outer diameter? I haven't heard of anyone doing that one before!
tony barnhill
Great Pumpkin - R.I.P
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<div class="ubbcode-block"><div class="ubbcode-header">Quote:]"hubs turned down 5/8""
You mean the outer diameter?[/QUOTE]
Yep...see the photos below...the one on the left is stock, the one on the right is modified
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Would this effect the strength very much?[/QUOTE]
Don't see how it could....there's a Canadian national champuion MGB that's been running with its lightened beam since the '60's & he never had a problem with it under any conditions.
Think about it - what good does the part between the frame rails do anyway other than holding the 2 ends together? The beam is only needed outboard of where its attached to the car.
You mean the outer diameter?[/QUOTE]
Yep...see the photos below...the one on the left is stock, the one on the right is modified
<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Would this effect the strength very much?[/QUOTE]
Don't see how it could....there's a Canadian national champuion MGB that's been running with its lightened beam since the '60's & he never had a problem with it under any conditions.
Think about it - what good does the part between the frame rails do anyway other than holding the 2 ends together? The beam is only needed outboard of where its attached to the car.
tony barnhill
Great Pumpkin - R.I.P
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& that's one the things I was shooting for, Doc - 50/50 with me in the car!! Plus I want it down around roadster weight when finished!
OP
Steve_S
Yoda
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Five pounds of sprung weight will not make a noticeable difference in a street car. That's like buying a 6-pack of soda to bring home. Will it make a difference on a race car? Well... arguably it could. But you'd have to be really pushing the envelope to actually see it. Twenty pounds would be far more noticeable.
As for strength, the center section seem to be mostly for keeping the two halves from flexing away from each other. Yes, removing material will weaken this link but more than likely it's stronger than needed for normal use. An engineer could certainly study the beam and advise on where to take out metal to make the least difference. Is the weight savings worth the reduced rigidity? Who knows!
As for strength, the center section seem to be mostly for keeping the two halves from flexing away from each other. Yes, removing material will weaken this link but more than likely it's stronger than needed for normal use. An engineer could certainly study the beam and advise on where to take out metal to make the least difference. Is the weight savings worth the reduced rigidity? Who knows!
tony barnhill
Great Pumpkin - R.I.P
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I agree for a street car...however, 6-ounces here & 6-ounces there pretty soon add up to 30 or 50 or more pounds of weight loss overall....that's how you've gotta think when lightening a racecar - from my unexperienced position....heck, I weighed all the undercoating we took off my car...it alone equaled almost 50 pounds!
& any unsprung weight that can be reduced is all totaqlly free!
& any unsprung weight that can be reduced is all totaqlly free!