TR4 Roll Over Bar (ROB) Competition type with backstays for use in Right Hand Drive (RHD) hard top cars especially the RevingtonTR fibreglass backlight frame. This ROB includes a fixed diagonal but no harness bar. A harness bar RTR9148HB or HB-1 can be bought separately, see below. We have a separate part number for this ROB suitable for TR4A-6 explained below

The design of this ROB with adjustable backstay feet makes it impractical to weld on a harness bar. This is not a disadvantage as we have designed and developed two stand alone transverse harness bars (RTR9148HB or HB-1) which are bolted to the wheel arch tops behind the backstays of the ROB, one to accept clip type harness shoulder straps and one intended for wrap around shoulder straps. These are listed below. Many owners, whether using their car on the road or the track, will find the use of a harness both comfortable and reassuring. If you have chosen to fit a ROB it is generally considered preferable, in the unfortunate event of the car rolling over, to be firmly strapped in. A full harness will achieve this with much greater effect then a lap and diagonal arrangement.

See Section 9 'SEAT BELTS' for suitable seat belts products of the harness variety.

The RevingtonTR ROB and Backlight Frame Arrangement explained

RevingtonTR have designed and produced an ingenious backlight and Surrey or hardtop arrangement with this ROB integral to the design, suitable for TR4, 4A, 5 and 250. This arrangement has been successfully fitted to many TR6's as well. See RTR7122 series for details of the full kit. The principle is that the main hoop of the ROB has a complex ring rolled shape so that it perfectly fits up inside our fibreglass backlight frame offering support to that frame whilst providing maximum rearward visibility. The main hoop is the same in all variations. The installation shown here for reference has a diagonal and roof bars.

The ROB's have been cleverly designed with sliding feet to accommodate different shapes and sizes of car; this will allow the main hoop of the ROB to fit neatly up inside the 'top hat' section of the backlight frame. Once the correct height has been established the foot sleeve is bolted firmly in place. This is a very tidy solution which results in rearward vision not being impaired.

As the wheel arches on TR4's are round and those on TR4A-6 are flattened, we supply different backstay feet for the TR4 (letter A in the part number denotes this) and TR4A-6 (letter B in the part number denotes this).

Whilst intended for use with our fibreglass backlight frame, the ROB's in this series (RTR9148) can be fitted under the original aluminium backlight frame or other backlight frames and hard tops available on the market. Unlike our fibreglass backlight frame for which these ROB's were designed, the original aluminium version has two bosses cast into the under face through which the hard top centre panel or surrey top are attached. As the ROB will sit directly below these access holes the main hoop incorporates two hollow ferrules to enable the hard top panel or surrey top to be fastened through both the ROB and the backlight frame. Longer bolts are required to fit the hard top centre panel or surrey top. If the bosses in an aluminium backlight frame are left in place, the ROB will sit slightly lower down. The bosses can be ground away a little to allow the ROB to sit higher.

The RTR9148 series ROB's offer considerable protection and additional stiffness as they are secured to the body at multiple points: -

Foot to floor and chassis (TR4)	Back stay feet	Main leg to wheel arch base	'B' Post bracket

RevingtonTR ROP's - The range

RevingtonTR supply a full range of Roll Over Protection (ROP) including ROB's and Full Roll Cages for the complete TR range. All ROB's allow the hood to be folded and unfolded unless specified otherwise. The following descriptions are used to describe the style of bars in our TR4-6 range.

ROAD BARS (RTR9148-1 series) have no diagonal brace with the option to purchase a separate transverse harness bar (RTR9148HB and HB-1).

COMPETITION BARS are supplied with fixed (RTR9148-2 series) or removable (RTR9148-3 series) diagonal brace, with the option to purchase a separate transverse harness bar (RTR9148HB and HB-1).

Please see below for other ROBs available for your car.

For Soft Top cars TR4-6 please see RTR9153 Series

Our range of Roll Over Protection (ROP's) is extensive, to help you decide what is best for you we have compiled an information sheet in an easy to follow tablature format. Please see IS0040 here or via the 'Further Reading' tab above.

Will this ROB give me adequate protection?

Things to consider.

The ROB's in this RTR9148 series sit in between the RTR9053 series where the main hoop and the back stays are secured to the body and the RTR9177 full cage where all main mountings are attached to the chassis. Yes, attaching all mountings to the chassis would be fundamentally better but by how much? Fitting any one of the ROP's in our range is a good idea, choosing the right one is a matter of personal choice of how much 'cotton wool' to wrap yourself in. The RTR9148 series ROB's give better protection than most as the assembly is bolted to the body of the car in 8 rather than the normal 4 places.

The most important information is this. The original concept of ROB design for TR's can be attributed to John Aley of Aley bars in the 1970's. A very early bar was fitted to John Welburn's black TR2 which he then rolled at Goodwood. There are photos of John, arms flaying as he rolled over and over. John walked away with no injuries. The bar was intact, the wheel arches dented but the bar nonetheless saved John life. The TR4-6 ROB listed here has multiple mountings - stronger still than TR2-3B installations. A few year later Frank Richardson had a similar unfortunate roll in qualifying for a TR Register race. In this case, Frank was also thankfully OK, the wheel arches were not damaged and the car, after a few dents were knocked out, raced the next day.

Fitting

We do not provide fitting instructions with this ROP as in general it will fit in one ideal place. We do however offer a sheet of fitting tips, which can be downloaded via the 'Further Reading' tab above.

This ROB includes:

• Rear Hoop with sliding feet
• 2 angled Back Stays with sliding feet
• RHD Fixed Diagonal Cross Brace
• Kit of fittings

This part is listed on the following pages of the website, where further information and background reading may be found.