Wasn't going to say anything but can't help myself.
There is a lot of BS spoken about low profile tyres improving handling and grip. Lets discuss:
1. What does "handling" mean? If it means feel through the steering wheel then yes lower profile tyres may very well make the steering feel sharper. If it means the car will do a particular autocross course faster, the answer is NOT necessarily.
2. What does "grip" mean? Well this one is easier to quantify as you can measure it. The low profile tyre fans will debate that low profile tyres provide more grip. This is absolutely NOT necessarily true and often the opposite.
Reasons: Grip is determined by how much friction there is between the road and the tyres. So many think a wider tyre will mean more grip. Seems logical, but this is ONLY the case if this wider tread surface remains on the ground, and this is where profile gets involved. A low profile tyre, with it's more rigid sidewalls that provides the sharper steering, will not be able to keep it's tread on the ground as well as the taller profile, less rigid sidewall, tyre. This is because as the body shell of the vehicle rolls around the corner, or goes over bumps, the suspension moves and unless your car has been designed for low profile tyres there might be some interesting wheel angles going on and heck only maybe 15% of that low profile tyre's tread surface is still able to stay connected to the road. Joe Blogs in his similar old/vintage car is following behind but he has higher profile tyres ... yes he has had to work harder to find the apex, but all of a sudden he is reeling in Mr Low Profile as his tyres have distorted but the result of this distortion is that more tread surface, maybe even nearly all of it, is still in contact with the ground. End result is Joe Blogs car corners faster as his car has more grip.
F1 is presently embarrassing itself by moving to low(er) profile tyres. The teams do not want to do this, but Pirelli are in full marketing mode and trying to make F1 more relevant to road cars. For some reason, big wheels and low profile tyres have become the modern thing, even though the ride is harsher and designing of the suspension for grip is more challenging as wheel angles have to be better controlled, but the upside is steering feel is improved (strange considering 99% of modern drivers don't give a stuff). The low profile fans will jump in with comments about how F1 will be able to run bigger brakes, etc. ... the current carbon fibre brakes are so good that tracks have to have their braking surfaces resealed after a F1 race, AND the FIA + fans would like to increase braking distances because this is one (of the many) reasons why passing is currently difficult. Note also F1 tracks are billiard table flat, but they still have a surprising amount of rear suspension travel (~150mm's).
If you ever find a photo of a F1 car in the middle of a corner and fully loaded up, the outer tyres are being murdered and the sidewall distortion is shocking, but the tread surface is all on the ground and they are gripping.
So low profile tyres on old cars, on real roads, IMO just does not make sense ... won't see any on my 1750, even if I raced it.
Pete
BTW: this has been tested by the Australian Top Gear show. The only useful thing they ever did. With exactly the same car and driver they tested the lap times with the optional low profile tyres and the standard tyres. The car lapped faster with the standard tyres. This test was done with a modern car so with an older car, the low profile tyre would likely be even slower.