Originally Posted By PaulJ
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My guess is that it was to increase ground clearance under the bellhousing, the lowest part of the car? If this was the case, reducing the ground clearance by lowering the bottom spring platform, suggested earlier, may very well sort out the problem, the downside being extra vigilance for speed bumps and rough roads. The ground clearance under the sump on the Caterham is 75mm [3"] whilst the Mog has a huge 125mm [5"] of clearance under the bellhousing and far more under the floor. This would indicate that there is at least an inch or even two that could be used to lower the front of the car by, thus putting the steering arms into a more parallel position, relative to the ground, so that on bump or bounce there will be less movement transmitted to the wheel, thus causing less bump steer........

Peter?


The minimum permitted vehicle ground clearance in many countries is 100 mm. I don't know about America but this applies in Australia and some European countries (not Italy). Ground clearance is not currently part of the European homologation specifications.

This is published in some Australian explanatory notes:

  • the vehicle must also retain 100mm ground clearance which
  • all measurements must be carried out with the vehicle on level ground in its normal operating but unladen state

I have found that some states in America have a rule that nothing can be lower than the bottom of a line taken between the wheel rims. This is to avoid the car scraping the road if it gets a flat tyre (or should that be tire? smile )

The European standard for speed humps has changed but there are many that conform to the old standard still in existence, not to mention those that never conformed to any standard. The old standard was 90 mm but a variation (presumably to allow for subsidence or other changes in road surface) of plus 10 mm was permitted. Since mathematics is not an opinion this means that there are many speed humps of 100 mm in existence and a 75 mm clearance is going to give you a nasty jolt and maybe leave you hung up on a bump or a garage entrance. The new standard is 80 mm but still with a plus 10 mm permitted.

I know all about this because our car, as delivered from the factory in 2012, had a loaded ground clearance of about 85 mm or less. Not only did we his a lot of speed humps but we could not get the car into our garage. All the speed humps around Southbourne, Bournemouth were a real hazard for us and they are fairly flat. The springs were changed under warranty and we now have 100 mm ground clearance.

Peter

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