roll cage rear down bars

[Racermb]

what is the reason for the rear down bars only going halfway back the frame rails on the longhorn, xr1, etc. vs. going all the way to the rear like on the blue/gray, mastersbilt, and others?

[Stede Bonnet]

It has to do with how the cars are designed & constructed. Masters and (Blue/Gray)Rocket are over-rail frame designs(the main frame rails go up and over the axle. With the rails run this way, up & over, the over-rail frames need the support to come from over the top with the rear down bars extending to the rear for strength and support. The Longhorns, GRT & XR1 are under-rail designs, the rails actually run under and over the rear axle, from the get-go. With under-rail you have support for tail of the car from underneath instead of like the over-rail frame, which is over the top. Below are some pics to help. One is the classic, "Over-Rail", the other is a GRT/Longhorn/XR1 type "Under-Rail"..

[manwplan]

It has to do with how the cars are designed & constructed. Masters and (Blue/Gray)Rocket are over-rail frame designs(the main frame rails go up and over the axle. With the rails run this way, up & over, the over-rail frames need the support to come from over the top with the rear down bars extending to the rear for strength and support. The Longhorns, GRT & XR1 are under-rail designs, the rails actually run under and over the rear axle, from the get-go. With under-rail you have support for tail of the car from underneath instead of like the over-rail frame, which is over the top. Below are some pics to help. One is the classic, "Over-Rail", the other is a GRT/Longhorn/XR1 type "Under-Rail"..

They might want to reconsider moving the down rails back like an over rail car. The fuel cell is lacking support as evidenced by the ejection or near ejection of the fuel cell in a crash.

[MasterSbilt_Racer]

They might want to reconsider moving the down rails back like an over rail car. The fuel cell is lacking support as evidenced by the ejection or near ejection of the fuel cell in a crash.

I think it is purposely done for flex in the back. You are right, those cars basically lose the rear clip in a violent wreck.

[Stede Bonnet]

They might want to reconsider moving the down rails back like an over rail car. The fuel cell is lacking support as evidenced by the ejection or near ejection of the fuel cell in a crash.

Those rails don't connect to the fuel cell. Fuel cells are usually supported front and back with a cross members fore and aft. Under-rail cars are far and away structurally superior to plain over-rail.