As per title.............
I have a factory fitted swan neck tow ball on a 2.8 crd GV.
I am using a clamp on bike rack on the tow ball ( great bit of kit ).

However the problem is that when an adult bike is on it , there is only about 4 inches clearance between the road surface and the bike wheel.

The swan neck would unbolt easy enough...............
But does anybody know of a 'taller' swan neck.

Thanks in hope

 

Not really sure about that one, a quick fudge would be to check eBay for a swan neck that fits a lower height car as the following directive applies to tow bar heights

Towball Height In theory, all towbars should set the ball at the correct height. Both the British Standard BS 150 1103:2007 and the EC Directive 94/20/EC, require the centre of the towball, when the towing vehicle is fully laden to its gross vehicle weight (but without the caravan attached) to be between 350 and 420mm from the ground. This should be compatible with any reasonably modern caravan, given one or two provisos:- If the car manufacturer chooses to set the tow ball height towards the upper end of the height range, and especially if the vehicle has a relatively high load carrying capacity, it may be that under normal operating load conditions the tow ball is significantly higher than this range. This is permissible according to the letter of the standard or directive requirements, but may result in difficulties achieving a well set-up outfit.

Hope this helps.

 

If the swan neck unbolts, then how about having a piece of flat mild steel plate with 4 holes drilled in it. Bolt the plate to the towing bracket through the bottom 2 holes then bolt the swan neck to the plate through the top 2 holes. You would need to calculate the plate dimensions and hole spacing to suit your requirements.

Edit: You could even drill extra holes to give you some vertical adjustment of the swan neck.

 

Sadly the swan neck part is more of a hook with a bolt thru it that holds it into a bracket.
Not a standard flange.
Have seen a flange adjuster that might give me 3 inches but for about £65 inc new ball.

Have settled to adjust the bike rack using a 25mm box section system .....much cheaper.