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Old 11-05-09, 06:02 PM
Claude Claude is offline
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Join Date: Jul 2008
Location: New Zealand
Posts: 153
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Quote:
Originally Posted by MYTA21 View Post
Does anyone have knowledge of tow bar capacity/ suitability of a tow bar on the 409? Obviously the car runs out of chassis before the axle, so not a job to consider lightly!
Thanks
Insofar as Bristols are hand made, there is no standard. You have several choices. If you are towing a garden trailer with very little capacity on local roads, and if your steel underneath has absolutely no rust, you may get by with a ball mounted to a typical tow bar mount affixed to the bumper mounts with a torsion resisting plate mounted to the bottom of the boot (provided you have no legal issues that might void insurance... in NZ certain changes require an engineer's certificate). Of course, when you go to sell the car the ball and mount should be removed, lest a future user thinks it has a mount of substance.

However, if you seek a serious mount to do proper towing, you need to fabricate a mount that affixes to the chassis in front of the rear axle (or to where the chassis terminates at the rear if an engineer can work that one out). This means either making a strong arch formed I-beam (or at least angle-iron) that runs over the axle, or that you use relatively flat steel (low profile U-beam on both sides) that goes under the axle, potentially restricting its movement.

This would be an engineering job requiring both calculation and design where you specify your towing capacity. The chassis is strong enough and the engine capable. Again, however, note the 409 is ancient, and a complete inspection for corrosion is essential. The areas of interest happen to be the most prone to rust in a 409. Also you may need to upgrade the cooling system for the engine and the transmission, and if the powertrain is of a similar vintage with no recent rebuilds, the extra burden may cause parts to fail.

Finally, it would be worth calling Bristol Cars to ask. I doubt you are the first, and if anyone would know, it would be Brian Marelli.

Claude
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