Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Tyre size change

Potentially heavier steering which is not a benefit trying to park a Mog in a tight spot without PAS

I have run 205/60 x 15 on my 1980 +8 for over 25 years once tyres for the original 14 ins rims became unsuitable. Toyo Proxes for the last 10 years once Yokohamas became unavailable.

My Toyo Proxes are now 10 years old and have to go now, though sadly they too are no longer available. My garagiste is suggesting the Hankook Ventus prime as the best currently in this size, as an ex-F1 suspension engineer I may bow to his advice unless anyone else knows better?

I have good experience using 195/65R15 tyres. I also changed the spare wheel to a 165R15 wheel of the Morgan 4/4 type to save weight. After 75000 km, the spare has never been used.

Harald

When I bought Monty 4 years ago, I immediately replaced his original 12 year old and very 'hard aged' Yoko 195/60s with a set of 185/65 Continental EcoContact 6, my theory being as a Plus 4 only weighs around 930kg you really don't need a wider tyre than 185. The rolling radius of a 185/65 R15 tyre is also almost identical to that of a 195/60 R15, so Monty's speedo remained spot on. The Continental EcoContact 6 was chosen as it's known for having a very soft sidewall, this is actually ideal on a light Morgan as most modern tyres are designed for far heavier cars, it's worth considering that even a little Mk7 Fiesta weighs 1,100kg these days.

Nearly all modern tyres in the size range we're discussing here will therefore have a sidewall carefully tuned to support well over 40kg more mass per corner than the very light Morgan Plus 4 suspends, it’s worth reminding ourselves that pneumatic tyres are your primary suspension system so if ride quality is important to you, the soft sidewall (by modern standards) of the Continental EcoContact 6 is actually ideal for a Trad.

In terms of grip, if you've ever driven an original Lotus Elan 130/Sprint you'll know just how much grip it has on a set of comically skinny 165s, further proof you don't need wider tyres than 185 on a Plus 4 comes from the fact I can put the 180hp tuned Monty up Prescott Hill in well under 60 seconds on a set of 185/65 Continental EcoContact 6 tyres.

If ride quality and steering feel are important to you then in my experience a set of 185/65 Continental EcoContact 6 are well worth considering, however, I do accept using 195/65 will give a bit more ground clearance which is always useful. The wider 195/65 tire will have a slightly taller sidewall but the increase over a 185/65 is not a great as you might first think. The truth is while you will be increasing the overall tire diameter by roughly 13mm, as a tyre is a circle it actually only lifts the axle and vehicle by half that amount, so the true increase in ground clearance will only be a modest 6.5mm.

Saying that, every little helps and as the lowered Monty could do will every additional millimetre I can find, I may well follow others commenting here and move up to a set of 195/65 R15s tyres. Furthermore, given I'm also about take Monty over 200 horsepower a little more tyre on the road could prove advantageous.

However, for those more concerned with ride quality, I can definitely recommend a set of the very compliant 185/65 Continental EcoContact 6 tyres, and if your Plus 4 produces under 200hp I'd also suggest a 185 section is more than enough tyre for a little 930kg Trad Plus 4.

185/70/15 Avon CR6ZZ for me expensive but my life depends on them. Brilliant in the wet or dry and it doesn't ground out.

After much deliberation I am thinking I will go with a 205/60 R15 which I am told will fit and be OK to replace the current 195/60 R15 - any experience of this change or should I just stick with the factory fit of the 195/60’s?

Not had experience though I put 205/55/15 on the rear of my 4/4’s 1972 and 1984.

The change you’re looking at is pretty minor..

https://tiresize.com/comparison/

I have 195/60R15 Michelin on the front wheels, 205/60R15 Yokohama on the rear wheels, and a 165R15 weight-saver spare wheel. The combination works very well on my four-seater Plus 4. My car was registered with s top speed of 240 km/h so the tyre choices were somewhat restricted. After getting a new Certifixate of Conformity from the factory, I no longer need V-marked tyres so next time I shall use 195/65R15 front and rear.

Harald

With respect, isn’t this very similar to your original question?
Despite all the replies, you seem to have totally discounted the 65 profile option! Might be worth reading them again before final decision. Good luck.