BIKES, WORK & FUN :
Plenty of manufacturers have tried to use Stock FXST type underslung shocks on a rubbermount softail design, which causes the engine unit to be pushed forward on the rubber mounts, breaking them.
A few others tried to solve this problem with a monoshock mounted horizontally under the seat, pushed by the top of the swingarm cantilever-style. This, rather obviously, just pulled the engine backwards with similar dire results. Attempts to ‘crutch’ these drawbacks by introducing multiple heim-jointed tie rods between engine and frame or replacing the rubber mounts with polyurethane just reintroduced the vibrations which the FXR design did away with.
Our design uses a monoshock unit (either Hagon or Pro-tech) with fully adjustable spring rate and damping, set vertically behind the gearbox. Our linkages impart a rising rate movement to the shock, just as state of the art Japanese race replicas do, giving far better handling qualities than any stock softail.
detail shot of monoshock assembly on a recent 330 tyre version
All pivot bearings used in the linkages are of the PTFE lined spherical type as used by H.D. and need no lubrication. Although it cant hurt!
We can build these frames with any amount of rake and stretch at no extra cost, and the rear-end can be made to accommodate any rear wheel. We can set these frames up for any amount of fat rear tyre clearance.
Made of 1.25” x .106” (cradle) & 1.75 x.106” (toptube) cold drawn seamless tube and T.I.G. welded in accurate jigs. Fatter tubes can be specified at no extra cost.
These frames, with shock and all linkages are priced at £1495.00
Mountings for fatbob tanks (be sure to tell us which type you want to use) can be added for £65.00 We also need to know what foot peg and sidestand arrangements you want. Stock FXST forwards or stock FXR mid-mounts are available.
There is no stock oil tank which will fit this frame without alteration, but we can supply a nice wraparound one which fits perfectly for
£175.00 in bare mild steel. We no longer offer stainless steel, sorry.
When designing this frame, it was necessary to make it 1.125” longer at the rear to accommodate the suspension.
To retain the belt drive, it will be necessary to use the following combination: 61-tooth rear pulley, 136-tooth belt and 32-tooth gearbox pulley. This is a good combination for highway use. For better acceleration, an aftermarket 29 or 30 tooth gearbox pulley can be used.
To run a narrow belt. the 135t twincam softail belt must be used, along with a 30t gearbox pulley.
Engine offsets for huge tyres can be easily accommodated, although this must be stipulated upon ordering. You need ¾” offset to run a 200 tyre or ½” offset to run a 180 tyre. We don’t recommend more than ¾” offset for street use. Bigger tyres can be had via offset kits or RSD gearboxes
Zodiac and others sell offsetting kits. These are available with 12mm, 25mm & 45mm longer gearbox mainshaft and 5th gear / pulley shaft. The 12mm kit will get you a 180 tyre, the 25 mm kit will allow you a theoretical 220, (or a 200 with the older 37mm belt) and the 45mm kit should be used for 230, 240, and 250 tyres You'll need a year 2000 -up FXST narrow 28mm belt to go with these.
RSD gearboxes should be used for 280 and up tyre widths.
This frame will accept Twin cam FLT / Roadking engine & trans assemblies, but oilsump modifications must be made, which we can undertake for £80.00