That would be a world of hurt, should you ever have an insurance claim, or other road accident in which the boys in blue attended!
(Just NOT worth the risk!)

And the A021Rs are used on some fairly heavy machinery on-track.
There is not really anything special about their build for a light-weight car, other than tread and compound.

Rainexpert3's are a soft compound, and also a 'soft' tyre, as that does get commented on in reviews when fitted to heavy cars.
They could be an acceptable compromise for now... until I change to different size rims...

Eugene - I agree way too risky but having seen the 'adjusted' tyres they look 'normal' - BIB would never notice provided the tyres had sufficient tread depth.
Most MOT testers never check road legality either provided the tread depth is over legal requirements.
I'm fortunate to have 4 half worn ao21's which I'm gonna use on Front, it's on the front where the Bintop tyres are crap, on a 7.
Problem with Bintop tyres is they are designed to work at higher pressures than the 16PSI I use on my 7, hence the squeeling.
Good luck with the rainexperts - Be careful I suspect they're gonna be crap too if you drive the 7 properly

Well... I am not a tyre engineer but... What are considered tintop tyres have, for instance, similar load ratings to the more specialised tyres. I am assuming that load ratings relate to the weight of the cars. On 185/60R13, 80 load rating is the same for Toyo R888R and on most, if not all tintop tyres of the same size... Which begs the question... Why are specialised tyres done with such high load ratings, even Caterham ZZR/ZZS are 83 load index rating... If they were going to be done for lighter cars, then ratings below 80 would be more than adequate...
Sorry I am being too pedantic.

I have to agree with Eugene. Tread and compound are more important.

I have driven to the Alps from Portugal and back, on Nankang XR-611 and survived. Maybe I am a bit of a driver.

Bloody hell! Buy anything legal and drive it... adjust driving style to tyres and visit the Douro Valley

Eugene
Sorry
Aren't we all forgetting these Caterham branded tyres https://caterhamparts.co.uk/other/2737-tyre-avon-18570-r13-cr322.html
They are 185/70r13 after all...

Yep - I really do not like those tyres...

But, I think I've made a decision!
I'm probably going to go with 185/60r13 Yoko A048-R's

Looking at my ground clearance I think I can handle a drop of 18.5mm
And at the price, I can cope with binning them if I really cant get along with the lower ride height.

Steve

Eugene
We are talking about road legal ones, right? As the newer ones suffer the same as A021R for competition use only.

Yeah, there are still E marked ones available...

Oh bugger...
They have all gone!
So, Toyo R888R's are the next choice!

Ok - tyres ordered!

Toyo Proxes R888R
2x 185/60r13 for the front - 2x 205/60r13 for the rear
The recommended rim size for the 185 is 5.0 – 6.5, and for the 205, 5.5 – 7.5.
I will be using 6 all round.

Eugene
Well done!!! You will be fine.

Eugene good luck with the 60 section Yoko's, When I first had my 7 - I had 60 section tyres they were fine apart from ground clearance and lowered the gearing a fair amount.
For my 1970 car they looked odd coz they were very small in diameter, standard fitting on my car is 165x13" which are about same rolling radius as 185/70x13"
I also tried 14" wheels with Yoko Ao48's in 195/60x14" these are about same rolling radius as 185/70x13", problem on my car was wheel offset required spacers and longer studs which I bought but they never felt'right' on the 7. OOI Also had these tyres on My Dutton without spacers, they were great on that car.

As I will have 205/60r13 on the rear I will have little difference in rolling radius...
But anyway, I also have a 5 speed gearbox, with 'specified' ratios, and my top-end is rather high at the moment!
And as Uncle Albert has the same engine as mine, and the same tyre sizes front and rear as I have ordered I don't foresee any real issues (he's on all our Le BOG Club runs, and has never had an issue with clearance...)

Eugene
And he eats all the pies.

eugene
I believe 205/60x13" work best on 7-8" wide rims, probably too wide for your 6" rims, Never tried 'em personally though - just what others have told me.