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Fitting anti-tramp bars to a V8
Chris Armitage (Tundra 2066) from Hampshire posted a note on the V8BB with useful information on fitting anti-tramp bars in conjunction with softer leaf springs which have led to significant improvements in handling and ride quality. (Nov 07)

In my opinion the standard V8 springs are too hard - their increased rate over the 1800 items being a compromise to give the axle better location to allow for the extra torque of the V8. So a few months ago I fitted standard 1800 MGBGT rubber bumper rear springs as an experiment. I had to have these lowered by around 1.25 inches and re-shaped, by Brost Forge in London, as new springs today are often of poor quality. The result was vastly improved ride comfort - a HUGE improvement. But the axle was not now mounted firmly enough, the softer springs allowing too much axle movement, meaning that the car steered from the rear under acceleration and deceleration. The softer springs also exposed the front (standard) anti-roll bar as being too soft, allowing the car to 'wallow' somewhat. I tried replacing the rubber spring pads (between the spring and the axle) with polyurethane items which gave only a marginal improvement.

For the next stage of this exercise I fitted anti-tramp bars (rubber bushed ones from Moss), with low expectations after negative comments from others, but in the event they have absolutely transformed the handling of the car. They are reasonably straightforward to fit, no harder than fitting replacement rear springs. The only modification to the car is the need to drill four small holes alongside each front mounting of the rear spring, to accommodate the bolts which locate the front bracket.

The result is a car which feels more solid and 'together'. Steering direction is unaffected under all power on - power off conditions and the comfort level is, compared to the standard V8 springs, a 'magic carpet ride'! Another benefit is much improved cornering, partly due to the softer rear springs. At least one original road test alluded to the harder rear springs impairing the handling. I have also now re-
fitted my Ron Hopkinson

thicker front anti-roll bar, which originally, in conjunction with the standard V8 set up, had made the ride unacceptably rough. However, with the softer 1800 rear springs I now seem to have the perfect combination, giving just the right level of taut feel to the handling without harshness.

Despite my initial expectations there is no detectable additional vibration or noise transmitted through the anti- tramp bars. I am generally not a great fan of performance modifications as the negatives usually outweigh the positives in my experience, but I would completely recommend the above changes.


Three final footnotes:

First my V8 has always ridden higher on one side (especially at the rear) than the other- as many seem to do. As part of the above changes I inserted spacers (amounting to about three quarters of an inch) between the spring & the axle on the 'higher' side to level it up. Usually this disparity would cause an uneven twist of the axle under acceleration and even more rear-end steer, but the anti-tramp bars take care of that issue as well.

Secondly, anti-tramp bars are primarily marketed to limit 'tramp' or wind up and the violent reaction of the axle under hard acceleration. This has never afflicted my car even with the 1800 springs fitted, as I value my standard powertrain too highly to risk damaging them, but the bars confer the other benefits as described here which are not mentioned it their marketing material. They should also make the springs last longer as they are no longer subject to the same violent twisting forces from the axle under load.

Finally, MG RV8s had anti-tramp bars fitted as standard and presumably therefore have rear spring rates appropriate for maximising ride comfort and handing rather than for axle location purposes. It is possible that the Factory MGBGTV8 would have been given this set up if BL's development budget in 1972-73 had been greater.