Dougal,
Looking through your website and recommendations for various Bristol cars I offer the following comments.
Do you know that the Bristol 400 has 16 inch rims that are only 3.5 inch wide.
I'm not a tyre expert but would have thought that the best tyre in your range for a 400 would be an Avon 165/80x 16
https://www.longstonetyres.co.uk/tyr...urbosteel.html
The 401 - 406 have 16 x 4.5 rims and I assume a 550 x 16 Michelin or 175/80x 16 would be best suited to those rims . Most 185/80x 16 certainly look too big on the 4.5 inch rim, but probably work OK
The 407, 408 & 409 all have 16x 5inch rims and the 185/80 x 16 could be suitable for them.
You comments would be appreciated.
Geoff