Changing from Heavy Ruby Rear Tyres to Light

[Colin Morgan]

Hi,

After many years of running a Ruby on heavy Firestone 4.50 x 17" rear tyres, I have just changed to 4.00/4.25 Longstones. 

The car sits lower at the back, the un-sprung weight is down, and the tyre no longer rubs on the inner wing on roundabouts.  

Previously, the speedo was reading spot-on, so perhaps it now reads a bit high?  However, the slight change in gearing means that acceleration is a (tiny) bit better.

Presumably, the habit of fitting these larger 4.50 x 17" tyres started when they were all that was available?  All four wheels had them when I acquired the car in 1997 - despite the front ones interfering with the steering lock.  

With the original size all around, this is much more how a Ruby was meant to be?  

Colin

[Peter Naulls]

Our Ruby ran on 4-50s for many years because, as you say, 4-00s were unavailable. They are indeed far too big! More recently I've been unimpressed with the Longstones which are on it at the moment and I'm wondering whether to try one of the various makes of 4-25s next time. Excelsior, TT Classic Roadmaster amongst them.

[Hugh Barnes]

That is interesting, Peter, I changed the Cabriolet to Longstones a couple of years ago (admittedly from some very elderly Dunlops) and have been more than happy with them...

[John Cornforth]

Hi

Our Pearl had 4.50 x 17's on the rear when we bought it 20 years ago. We knew they were of different makes, but didn't realise that they were of rather different diameters. After putting on new 4.00/4.25 Excelsiors she ran happily in a straight line for the first time.

[Peter Naulls]

Very interesting. My main disatisfaction at Longstones is the rate at which they've worn out, I reckon 8 - 9000 miles before I have to change them. I've also found one of them is breaking up internally, the reason I've been getting repeated punctures according to my local Quick-Fit type place. On the plus side they look right and the car handles OK.

[Martin Baker]

I tried Longstones on my 1938 Pearl but found they were expensive and wore out standing still!
I'm now using Excelsior which seem fine and are lasting OK.

[Colin Morgan]

The just retired rear 4.50 Firestones have done 12,000 miles - even wear down to about 2mm tread running at 22psi. (Have gone through a couple of pairs of tyres on the front in the same period. Running the Longstones at 26.)

[Hugh Barnes]

From memory, I have done around 4-5000 miles on the Longstones. I cannot make an objective evaluation of their wear just at the moment but I recall they dont appear to have worn that badly. When I can look at them next (next week) I will make a more informed comment.

Does anyone have any brand new Longstones to hand and can confirm tread depth before any wear takes place?

[Colin Morgan]

Tread depth on my just fitted 4.00/4.25 x 17 Longstones is 7.5mm.

[GK5268]

I had Longstone tyres on my Ruby, had some very serious deterioration of the rubber after only a year, heavy cracking to the sidewalls, wore out after 8,000 miles & a total of two years service.

Tyres also caused the rear end of the car to "hop", which was a bit disconcerting.

Despite being advertised as being correct for a Ruby, they are NOT, they are dual marked as 4.00/4.25 x 17, which is nonsense, a tyre can only be one size, they are in fact a 4.25 tyre, so still too big. This is misleading.

I replaced the Longstones with reproduction tyres based on an original Michelin tyre (Longstones 17" tyres are a made-up tread), which is to the correct 4.00 x 17 size and the correct tyre made a difference to the car's handling, the hop disappeared, steering was lighter and the car nicer to drive.

Howard Annett, President of the A7OC (London), gets these made and a new batch is due to be available soon.