Topic: Roll Cage Tube Size Car Race Weight
Section 3.E.1.a specifies tube diameter size minimum based on car weight "as raced", does this as raced weight include driver weight?
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Section 3.E.1.a specifies tube diameter size minimum based on car weight "as raced", does this as raced weight include driver weight?
No, but if you think that you are close enough on weight due to your size, just go with 1.75 The extra weight isn't great enough to make a difference for 99% of us.
I have never seen scales at a Lemons race; so, I doubt anybody will ever question your choice unless you put 1.5 is a malaise-era Caddy.
For our BMW 633 Lemons car, which weighs almost 2700 lbs in race trim, 1.75 x .095 would have been fine. We built the cage with .120-wall. There is certainly a weight penalty. For example: 1.75 x .095 is 1.679 lbs/inear foot; 1.75 x .120 is 2.089 lbs/linear foot. We probably used 80” of tubing in our BMW cage. So, that's almost 25% heavier for the 1.75" x .120 cage. Strength of the tubing goes up with increase in both diameter and wall thickness. The 1.75 x .120 is about 20% stronger that .095. (I am not an engineer. Just looking at some online charts.) Overall, I prefer strength over weight savings.
--bb
In my experience 120 is easier to weld than 095. Especially at intersections of coped angles where the leading edge gets super thin. Also, total weight difference for my cage was 12#.
Have fun.
In my experience 120 is easier to weld than 095. Especially at intersections of coped angles where the leading edge gets super thin. Also, total weight difference for my cage was 12#.
Have fun.
This is an excellent point thank you!
In my experience 120 is easier to weld than 095. Especially at intersections of coped angles where the leading edge gets super thin. Also, total weight difference for my cage was 12#.
Have fun.
That is a good point as well for people that can weld a cage but are not amazing welders. Welding thin metal sucks.
I have never seen scales at a Lemons race; so, I doubt anybody will ever question your choice unless you put 1.5 is a malaise-era Caddy.
--bb
The judges have a basic idea on what cars weigh in race trim. The Cordoba, Cadillac's and other full size cars will draw attention of tubing size but most people building the larger cars all end up putting the bigger tubing in it anyway.
The curb weight of our AMC Javelin is about 3300 lbs. We stripped some weight by removing the interior but we added a lot of steel to reinforce the body and deal with rust. We chose run 1.75" anyway since we didn't have scales.
I have never seen scales at a Lemons race; so, I doubt anybody will ever question your choice unless you put 1.5 is a malaise-era Caddy.
For our BMW 633 Lemons car, which weighs almost 2700 lbs in race trim, 1.75 x .095 would have been fine. We built the cage with .120-wall. There is certainly a weight penalty. For example: 1.75 x .095 is 1.679 lbs/inear foot; 1.75 x .120 is 2.089 lbs/linear foot. We probably used 80” of tubing in our BMW cage. So, that's almost 25% heavier for the 1.75" x .120 cage. Strength of the tubing goes up with increase in both diameter and wall thickness. The 1.75 x .120 is about 20% stronger that .095. (I am not an engineer. Just looking at some online charts.) Overall, I prefer strength over weight savings.
--bb
100% agree! Since our first car (2001 New Beetle, approx 3000 lbs stock) could have used the smallest, lightest tubing, I asked our cage builder what he recommended when we were discussing the cage and price. He is a very experienced racer and cage builder, and his firm and direct reply was that if we wanted anything other than 1.75" x .120 tubing, we'd need to go somewhere else no matter what the car weighed. His reasoning was that if we ever "used" the roll cage, we'd never wish we'd saved weight or money. That made perfect sense and made me a believer. When that car hit the wall hard in Atlanta a couple of years later and our driver had only a few bruises from the seat side - but it took us hours to get the car onto the trailer - that belief was confirmed.
His reasoning was that if we ever "used" the roll cage, we'd never wish we'd saved weight or money.
This...
we just had the cage put in our new car and while we could have snuck in with the 1.50 inch tubing we went with 1.75 inch. our thought process was that while Lemons is super fun and we want to continue doing this for years to come it is not a "source of income" we do it for the fun and thrill and while it would be amazing to win the first priority has to be going home safe and whole. so we went with the bigger stronger cage, if that means that we are slightly slower so be it. also on a side note about "winning" I have seen a lot slower cars do better than the faster cars because they were consistent and were able to stay out and just keep turning laps, this mess more track time as well.
hope this add some perspective and was helpful
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