Yep, I can imagine the back end of a Grinall letting go in the wet would be quite an emotional experience.

I know a keen rider that lost the rear during a summer shower. Mind you, it was a Triumph Rocket, so that may have had something to do with it.

9 times out of 10, more tread is better.

The Grinnall was the three-wheeler open body two-seater car type rather than trike (IIRC they might have done a four-wheel version too, but I'm not sure about that). Very comfortable seat as I remember it and I said I was impressed with the smooth gears changes as we went from village to open road back to village and the driver smiled and said he'd kept it in the one gear. Obviously it was allowed 1 mm just that I wasn't used to seeing such low tread and it was on for what I was used to at the time a wide tyre making it look even lower. I was used to fully open cars, and without helmet, helmets are for tracks not public roads as far as I'm concerned and I don't like to wear a helmet on a track either.

2 hours ago, OccyVRS said:

In the dry, low tread is actually better!

Yes but if the car is actually used or driven then this is England so the drive could start out dry and go to wet or worse light rain and greasy surfaces. The club had a couple of Ariel Atom owners bring their cars to a charity passenger ride event, one had clever semi-track type tyres on and could hardly go out for runs and the other was owned by someone that actually used the car with full road tyres and went out all the time, it was November in Birmingham!

On a performance car I'd give a set of tyres up to 1,000-miles to see if I could get on with them and if I couldn't I'd change them, what's the point of having a performance vehicle that doesn't fully handle, unfortunately the days of being able to do such are long ago now - but to a lesser extent the principle still applies but the limitations are greater and fully accepted and adjusted for now.

4 minutes ago, nta16 said:

I don't like to wear a helmet on a track either.

There's quite a good debate on the uses of helmets vs harnesses vs HANS. I wear a helmet on track days as I figure it can't hurt, however I'm in a fully road going vehicle with factory airbags and not chasing lap times. Were I to be doing anything more serious, I'd want a proper seat and harness. IMO something like HANS isn't needed, as long as you have airbags. If you're in something that doesn't (such as an Atom), you should have a helmet, harness and HANS.

I'd always wear something and not need it, rather than not wear it and need it. Whenever I go out on my mountain bike, even if I'm having a relatively relaxed day at the bike park or local trails, I will always wear a full face helmet, spine protector and pads. Anything more, and you'll find me wearing Moto body armour. You only get one life!

8 minutes ago, nta16 said:

Yes but if the car is actually used or driven then this is England

I would also suggest that this also raises the question of road surface. I've driven a car on semi slicks (not slicks, though) and I can imagine that on the majority of UK roads, the surface condition would make it terrifying. This is also true of normal road tyres - if you're going over a rubbish surface (approx 99.9% of the UK road network) then having higher blocks will surely give you better traction when the tyre is upset by such bumps, etc.

2 hours ago, OccyVRS said:

I've driven a car on semi slicks (not slicks, though) and I can imagine that on the majority of UK roads, the surface condition would make it terrifying.

They are grippier on the road even during wet conditions up to the point of standing water, granted wets will give a better lap time in wet conditions but road tyres wouldn't and if you were driving on slicks on the road in wet conditions you would not be driving to the limit, you would likely be sheltering during the worst of it.

I did (summer) hillclimbs in Northern France till 2004, I would leave the car on slicks the whole weekend as the Gendarmes would close the roads during the practice and race sessions and were very obliging outside of those times as everyone behaved sensibly. One year I drove to and from the event from Sussex on slicks as my trailer had not been returned by a borrower.

16 hours ago, StevesTruck said:

I can imagine the back end of a Grinall letting go in the wet would be quite an emotional experience.

More 'kinell than Grinall ...