Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Tyre pressure question

This might sound like a daft/simple question but I have no reference points for the following:

A 1973 4/4 4 seater, retro fitted with 195/60 15 tyres (on wires if that makes any difference, but I doubt very much)

The engine is not standard (1.8 twincam), so I don’t know if the weight increase and/or power increase will have a minimal or significant impact?.

The car feels fine on the road but I am very aware that the pressures haven’t been checked for almost a year (other than me checking that they are all of a similar psi and adjusted to the highest reading of the four)

To clarify,I am not a complete novice, I know a lot of the cars quirks, reasonably competent with a set of spanner’s and I have literally been brought up with the car, but what sounds like the simplest, most routine maintenance, is something that I don’t really want to leave to guesswork/look/feel.

Any advice will be greatly received.

Have a great weekend and thank you in advance.

22 psig. The tyres are part of the suspension. Look up GoMog website and grease the front and the leaf springs

Thanks John, I have had a look and that all makes sense.

Some folk seem to enjoy higher tyre pressures but I keep mine at the factory recommended 22 psi all round despite it being the heaviest of later classics. Even then the tyre wear seems to be greatest at the centre over 31,000 miles although I do cycle the spare as well.

31K you're doing well.

Yep! you'll find tyre fitters arguing with you re. the 22 psi when you change them but that is the factory recommended setting. The cars are so light that they really add little load to the tyres and to keep the tread fully in contact with the road 22psi is about right although you might have to play around very slightly as different brands have varying wall stiffness and this will have an effect on getting the maximum contact with the road and, as has already been said. the tyre is the first part of the overall suspension system. For instance if you are finding your suspension a tad hard you could consider upping you tyre profile to 65 from 60 and this will give you a diameter increase of around 20mm, a greater ground clearance of about 10mm but will improve the ride quite a bit. Not sure what is standard on your age 4/4 but I'm sure they had 15" rims with quite a large profile but going up to 65 from 60 will make little difference to the registered speed. How ever before any real assessment can be made a perfectly working and serviced suspension system is your first starting point. such small differences say through lack of service or poor adjustment can make a great car feel like a shed!

The CX plus four also runs on low pressure at 28 psig

Not being a lightweight myself, I find 22 too soft - easy to squeal tyres on short sharp corners, so I run 23 front 24 rear, unless I have additional weight on the rack in which case I might raise the rears by another 2 psi.

I ran my 3.7l Roadster on 24 front 26 rear based upon claculation P Jenks did on here based upon the caravan club info
I replaced the tyres on age at 28k.

My two cents? FWIW

There is nothing as important to Morgan comfort and handling as tyre pressure. Morgans are amongst the lightest cars in the world. It is very rare, if ever, that a tyre seller encounters
one. Distrust their recommendation. MMC handbook tyre pressure recommendations are one of the few bits in the Handbooks that are constantly spot on.

However, it is best to verify your tyre patch to confrim you have the right psi to be sure, BEFORE you miss the joy of the proper pressure and pre-wear your rubber prematurely. Each
Morgan, loaded and unloaded should be checked, front and rear and that should be remembered. For example, my Morgan was made lighter than most (unladen @ 850 kilos). I found
that 20psi is fine is unladen. Much earlier mog weigh much less.

(I occasionally add 4-5 psi if I am going to do lots of motorway mileage, (very rare). Higher than advisable pressures significantly lower fuel consumption (while prejudicing handling and fun).

I posted how to determine one's personal tyre patch. However, one can merely follow one of the methods a search turns up. Essentially, they all are means of confirming whether your tyre
print is even across the tread (WHEN THE TYRES ARE HOT which takes about 20-30 minutes) Tyre pressure increases with a bit of non-stop&go driving as their inner air heats. Confirm
mog's your patch, note your psi and then take it again when the tyres cool so you will know what to inflate to when they are cold or hot. Confirming the imprint when the tyres are cold
means they will effectively.be overinflated and wear the center.

BTW, as a rule,I have found most Morgans have overinflated tyres. Tyre sellers and consumers feel that the tyres' psi should be the same as their other vehicles weighing double their
Morgans. This habit is easy to spot as they will have more wear in the center of the tyres. Pity. It takes an hour to adjust to the better tractability and comfort, but it is merely common
sense confirming the evidence of your eyes. We all adapt unknowingly to automobile anomalies and poor traction. But these cars become more exciting and the tyres last longer with
the right pressure.


Yes. The best rubber does not last long. Tyre compounds are a compromise between longevity and quality handling. I figure since mogging is a hobby, I should spend whatever I need to
enjoy it to fullest. Why make a hobby less hobby that it can be? he only tyres I have found that managed that last 12-15k..so with more than one Morgan I was constantly changing them.
But then, I dislike driving on tyres when their tread is less than perfect. Happily, I found one tyre in the UK that lasted longer you mileage and handled as well wet or dry.

L.