PerversePolisher's GSX-R 7/11 Subframe

The subframe for my GSX-R was manufactured by Steelheart Engineering in Kent (01227 7-11 234). After setting the frame up in a jig the frame was checked for "squareness" (i.e. all beams running parallel with each other). The first job to undertake was the removal of the subframe. This was swiftly done with an angle-grinder, then ground back and polished to ensure a good clean surface to weld the mounting lugs onto.

A pair of mounting lugs were made from a billet of ally. They were manufactured identically and checked carefully to ensure they were exactly the same.

Once Lee was happy with them he measured up and marked the frame where the lugs would be mounted. Each lug was held in place and temporarily "spot" welded into position. Once we were happy that this was correct they were welded on neatly.

If you've ever seen Lee at Steelheart in action, you will know he's something of a perfectionist and a real craftsman. He made the subframe by bending and flattening tube, then welding the tubes together. Drilling holes in the appropriate places for mounting to the main frame rails and to fix the seat unit in the correct position.

Lee offered up the seat unit and decided that the subframe would need a plate to mount a tail light onto and somewhere to hang a number-plate. He neatly cut into the fibre glass of the seat unit then located it on the frame and marked exactly where the plates would go.

The undertray had been forgoten about until this time, and when fitted it clashed with the lower rail of the subframe (essential this one as it needs to take the weight of my fat arse). So a slot was cut into the undertray. I liked this idea, as it shows a little of the subframe and you can see something a little special has been done.

The principles of the engineering involved are exactly the same as those used in UK_Lee's article on subframe conversions. Which you should read if you want to attempt this yourself