Interpreting MSA rule book re roll cages
Discussion
Anyone out there use this book? I am trying to understand the rules re roll cage tube sizes.
Car is a 1967 Lotus Elan. I plan to use it in Street Class drag racing, sprints and hill climbs. It will be a hardtop. The regs seem to indicate that I can get away with just a hoop of 45mm diameter - 1.6.1 (c)
My question is - I want to fit a full roll cage as we need to stiffen up the chassis as it is as stiff as a strip of liquorice, even when modified to 26R standard. So, does the additional tubing have to also be 45mm diameter or can I use 38mm as I would class these tubes as optional? I plan to use T45.
Car is a 1967 Lotus Elan. I plan to use it in Street Class drag racing, sprints and hill climbs. It will be a hardtop. The regs seem to indicate that I can get away with just a hoop of 45mm diameter - 1.6.1 (c)
My question is - I want to fit a full roll cage as we need to stiffen up the chassis as it is as stiff as a strip of liquorice, even when modified to 26R standard. So, does the additional tubing have to also be 45mm diameter or can I use 38mm as I would class these tubes as optional? I plan to use T45.
Edited by stevebroad on Wednesday 25th March 10:03
The MSA book uses different sizes and thicknesses than those accepted by the drag racing world.
If I remember correctly the MSA has inch and three quarter tubing with a 2mm wall and the drag book has inch and five eighths with just over 3mm wall.
Please don't accept that as gospel!
This makes it awkward to create a cage that is acceptable by both, the only way I could think of was to use inch and three quarter with the thicker wall.
This then is heavier than necessary.
Is it a convertible car as that affects the trigger point for bars/cage?
If you aren't going to go that fast it may be better to be legal for the cornering stuff.
I would get lots of advice before starting.
Hope this helps.
If I remember correctly the MSA has inch and three quarter tubing with a 2mm wall and the drag book has inch and five eighths with just over 3mm wall.
Please don't accept that as gospel!
This makes it awkward to create a cage that is acceptable by both, the only way I could think of was to use inch and three quarter with the thicker wall.
This then is heavier than necessary.
Is it a convertible car as that affects the trigger point for bars/cage?
If you aren't going to go that fast it may be better to be legal for the cornering stuff.
I would get lots of advice before starting.
Hope this helps.
stevebroad said:
Anyone out there use this book? I am trying to understand the rules re roll cage tube sizes.
Car is a 1967 Lotus Elan. I plan to use it in Street Class drag racing, sprints and hill climbs. It will be a hardtop. The regs seem to indicate that I can get away with just a hoop of 45mm diameter - 1.6.1 (c)
My question is - I want to fit a full roll cage as we need to stiffen up the chassis as it is as stiff as a strip of liquorice, even when modified to 26R standard. So, does the additional tubing have to also be 45mm diameter or can I use 38mm as I would class these tubes as optional? I plan to use T45.
Give Andy a ring at http://www.robinson-race-cars.co.uk/, he has an old Elan in the workshop having a rolecage installed at the moment for an FiA Historic racing. He knows his stuff on regs & tubes.Car is a 1967 Lotus Elan. I plan to use it in Street Class drag racing, sprints and hill climbs. It will be a hardtop. The regs seem to indicate that I can get away with just a hoop of 45mm diameter - 1.6.1 (c)
My question is - I want to fit a full roll cage as we need to stiffen up the chassis as it is as stiff as a strip of liquorice, even when modified to 26R standard. So, does the additional tubing have to also be 45mm diameter or can I use 38mm as I would class these tubes as optional? I plan to use T45.
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