2006 987 on full lock at low speed....crunchy feeling???

[Tiggsy]

First spotted this reversing off the drive under full lock in the winter - the sensation was that the tyres where "crunching" on ice or snow on the drive. I assumed, as they are pretty fat/wide tyres they just had more resistance to the ground when going slow on full turn.

But weather is now fine and its still doing it...so starting to think it may not be the tyres/road surface! What would make it feel like that....full lock, slow in reverse....feels like tyres are going over hard packed snow.....but assume it may well be feedback coming from elsewhere in the steering system and not the rubber (or even wheels) themselves???