Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Tyres choices and advice

I have followed this tread with interest as I need to replace my Conti CT 22 on my 70th Anniversary running on STEEL RIMS.

Do I have to stick with the current profile of 165x80x15 which gives a limited choice of tyres or can I move to a 70 profile in which there is a greater choice of tyres - if so what profile and make should I be looking at.

Will changing from the existing profile cause any issues with clearance or road holding and would my existing spare be ok in an emergency or do I change all 5 tyres.

Gordon

2006 4/4 70th Anniversary Duratec

Advice from RoSPA:

Tyres that have been in storage should not be placed into use if they are over 6 years old, from their date of manufacture.
When a tyre has been in use, the effects of ageing are lessened to a degree, but such tyres should be replaced after 10 years.

The effects of ageing can be brought about prematurely in several conditions:

1. Tyres fitted as spare wheels or used on caravans and trailers may age prematurely. If tyres on caravans or trailers are not in regular use, then they should be inspected before every journey.

2. Tyres used predominantly in coastal areas will age at a greater rate due to the saline conditions

3 several cleaning products may also harm the chemicals in the rubber.

There doesn't seem to be any "Official" advice or Construction and Use rules relating specifically to age.

BUT, it does seem that the spare on a Mog will age more rapidly than the road contact wheels, and if out in the sun near the coast might be toast in much less time than the road tyres.

Tarka is 3 years old on 2 April: the rear tyres are down to 3.5mm. Given the car has run 30,700 I rather doubt they are original... anyway, time to change them I think.

The question is to what. I have Avon ZZ3s, but the new ZZ5 isn't available in the size needed for the front and anyway I wouldn't fit different make tyres front and rear.

Suggestions anyone?

I view personal choice on tyres as being as divisive as oil choice, I'm afraid. What I may prefer as it suits me probably won't suit someone else. Clearly they suit many or they would be out of business, but you follow my thinking!

The subject of directional tyres is a thorny one as the spare will only fit one side, although in practice if it means awaiting a breakdown van or chucking the spare on rotating backwards it's a no-brainer for me. I'd rather sit in the warm with a cuppa than stand for a few hours next to nowhere.

The reality is that in real terms, the cost of tyres is a very good life insurance move. You live or die on a footprint the size of a hand on each corner, so don't mess about if in doubt.

Does THIS help at all..?

Steve I found the chart very useful and the difference in tyre size and speedo readings moving from 165x80x15 to 185x70x15 looks acceptable.

My only concern would be regarding tyre clearance and road holding- any advice please.

Gordon

One other thing to bear in mind is that a 185 section tyre is going to be 10mm wider on each side than a 165 tyre, and so might protrude beyond your wings if they are cut tight to the existing tyres.

Personally I have never had any problem with traction and roadholding on 165 section tyres, and my 4/4 puts out something over 165bhp. I also think the look of the 165 section suits the aesthetics of the 5" rims better than the wider tyres.

It has to be said, however, that CT22s are not ideal, their wet grip is very poor in my experience.

There are many different opinions, as Steve says, and much of it depends on your driving style and preference, but personally I find the Vredestein Sprint Classic to be ideally suited to my form of 'enthusiastic' driving. After yesterday's jaunt to Bicester, I can also report that their performance on wet roads is absolutely fine. I found some quiet twisty B roads to play on, and at no time did they give me any cause for concern.

I run 185/70 on original rims and have no problems with clearance. The steering charakteristics changed a little bit torwards precision. Road holding is much better with the Vred.classics compared to the aged Contis I had before - but comparing 5year aged tyres to new ones may be unfair. The 185 tyres still look slim to my eyes.

The place to watch for clearance is at the front, where the sidewall is very close to the upper cross-head tube/upper damper mounting. It's only a few mm. Everywhere else should be OK.

I lost 2 front winter tyres on my autocross car by not checking the clearence.The gap is very marginal at the top head.

Having considered all the valid points and options I think I stay with the 165x80 option. The CT22 give a very low wet rating of E and the Vred Classics are exempt from the rating scheme. Moving away from the classic tyre to the new Vred T TRAC or T Trac 2 with a B wet rating look a good option.

Thanks for all your inputs.

Gordon

We have fitted quite a few sets of Avon ZV7, and everyone has been really pleased with them, and not stupid money. Having said that, they have only been fitted to big saloon cars...

I chose Michelin Pilot 3 (Pilot 4 not available yet in 2055516), they definitely grip better in the wet than the ZZ3s they replaced (the back end was very lively with the ZZ3s, not "lost" the back end yet with the Pilots).

Yet to drive them in the dry