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?

Re: Roll Cage Tube Size Car Race 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.

1990 RX7 "Mazdarita"  1964 Sunbeam Imp (IOE 2013 Sears Pointless) 2002 Jaguar x-type (Winner C-Class 2021 Sears Pointless)
Gone bye-bye
1994 Jaguar XJ12 (Winner C-Class 2013 Sears Pointless)  1980 Rover SD1 (I Got Screwed 2014 Return of Lemonites)

Re: Roll Cage Tube Size Car Race Weight

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

Re: Roll Cage Tube Size Car Race Weight

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.

Tri-Lamb Motorsports ‘87 528e

Re: Roll Cage Tube Size Car Race Weight

zakp73 wrote:

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!

Re: Roll Cage Tube Size Car Race Weight

zakp73 wrote:

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.

1992 Saturn SL2 (retired) - Elmo's Revenge -  Class B winner, Heroic Fix winner x2
1969 Rover P6B 3500S(sold) - Super G-Rover - I.O.E Winner, Class C Winner
1996 Saturn SW2 - Elmo's Revenge (reborn!), Saturn SL1  Dazzleship
1974 AMC Javelin - Oscar's Trash heap - IOE,”Organizer's Choice" and "I got Screwed" award winner

7 (edited by chaase 2021-07-29 07:00 AM)

Re: Roll Cage Tube Size Car Race Weight

billy bee wrote:

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.

1992 Saturn SL2 (retired) - Elmo's Revenge -  Class B winner, Heroic Fix winner x2
1969 Rover P6B 3500S(sold) - Super G-Rover - I.O.E Winner, Class C Winner
1996 Saturn SW2 - Elmo's Revenge (reborn!), Saturn SL1  Dazzleship
1974 AMC Javelin - Oscar's Trash heap - IOE,”Organizer's Choice" and "I got Screwed" award winner