Tyres

[bobharvey]

I’m sure this is a pretty well worn and much discussed issue. I’m not a great fan of crossplies being just old enough to remember them, but neither do I want steering that gives me a workout.
There are radicals made for vans and light 4x4’s that have stiff-ish sidewalls and presumably hardwearing less grippy rubber (I remember some Czechoslovak ones on my Saab 96 half a lifetime ago that squealed amusingly rounding bends, Barum I think)
Any tried and tested makes/sizes?

[Keith Clements]

Hi Bob,
Yes you are right, it is a much discussed subject.
The main issue with Javelins is that SOME Javelins suffer from the ovesize tyres rubbing on the wheel arches.
Personally, I would not go back to crossplies, but some do still prefer them.
The club has a deal with Longstone tyres so I suggest ordering via the club. My daughter's Javelin has them on. With 5 or 6 people on board and hard cornering you might get a bit of rubbing. The amount of rub depends on the set-up of the suspension (ride height and panhard rod), shock absorbers and quality of springs.
The other issue is that the oversize spare will not fit in the spare wheel carrier. JowettTalk has solution to that.
https://jowett.net/forum/viewtopic.php? ... ier#p23155
https://jowett.net/forum/viewtopic.php?p=43598#p43598
https://jowett.net/forum/viewtopic.php? ... ier#p41596

[David Morris]

Hi Bob,

In my opinion, it's all down to what you want to ask your Javelin to do? If she is going to be used for taking you and your family to summer-time shows and the occasional shopping trip, then I would advocate using cross plies. The steering should be lighter, the spare will fit into the spare wheel tray and there should be no issues with the side walls rubbing on the inner wheel arches, but unfortunately expect her to follow poor road repairs or badly in-filled trenches that leave a groove in the road surface. ( why on earth don't we have roadside ducts to carry the multiplicity of utility services, like some other enlightened countries? )

If you are much more inclined to be taking her to competitive events, where she will be asked to rediscover her excellent handling, then by all means explore using radials, but research the anticipated problems first.

Whatever type of tyre, you will need to explore how to get them fitted and balanced properly. My advice is to seek an old-established tyre company that still has the mandrels for the larger central hole in the steel wheel. This is likely to be a firm that also fits tyres for the larger commercial vehicles.

Good hunting and stay safe,

David

[Keith Clements]

The braking distance is better with radials so even more care and anticipation is required with crossplies. There are also reports that crossply rubber deteriorates quicker so tyres are bad after 4 years.

[Chris Spencer]

Its all down to what you want to spend & your expectations - Far too many think that can transform a Javelins road holding by fitting a set of radial tyres - purchase good quality crossplys and your Javelin will handle fine - purchase cheap crossplys / taxi tyres / cheap radials and I fail to see how you can expect the car to handle - I run 'Avon Tourist' crossplys on my Javelin - it handles well - travels at speed - steers correctly - then again I don't expect to compete in it - nor do I expect unrealistic speeds & performance out of it - if I wanted that I'd go & purchase a car capable of such

[Mike Allfrey]

Hello Folks,

My Jupiter is fitted with Excelsior cross-ply tyres that were bought locally in Melbourne. We have so many speed restrictions, it is just not worth converting to radial tyres, which are probably all of tubeless type and would need tubes when fitted to Jowett wheels.

A week ago, I had a set of Continentals fitted to my Rover 75, it was a balance and wheel alignment included job. I was surprised to see that there are no external balance weights. The tyres were inflated with nitrogen, as were the Pirellis before.

There was an amusing, to me, case about tyres for a Rover 75. A fellow wanted a very cheap set of tyres for his car, he obtained some obscure brand from China direct. The tyres would not stay in balance foe even short periods of time, and he roundly blamed MG Rover!

A warning about radials, they have a use-by date and, in the event of an accident, could cause problems if that date has expired - even though there may be plenty of tread left. I have not yet found a date on the Jupiter's tyres, which have been in use for quite a number of years now.

[bobharvey]

I’m not really aiming to compete or even hustle along on a long trip, but I do think crossplies are outdated and inferior. I’m sure designers like Issigonis and Palmer would have chosen them for their innovative cars had they been available. The Avon period radicals are not only £250 a pop, but, if they are a period replica, likely to be inferior in design, manufacture, and compound technology to even a budget modern tyre. Have you compared the quality of a Hyundai body shell to a 1960’s Rover or Jaguar?? Technology, particularly manufacturing, has just, well, improved, in 50yr.
I’m not at all sure that being made in China (like most non- premium tyres, and the iPhone in your pocket) or made for a taxi, is a damning epithet. Actually a TX4, beings rather dated design, is probably fairly similar to a Javelin in many ways. Certainly it’s tyre priorities, quietness, durability, price, forget the racing handling, aren’t a bad match for a classic car.
My big concern is the 175 profile. Apart from the spare wheel tray and the slight increase in gearing (sorry officer) rubbing at full lock seems the likeliest downside. I’d very much like to hear the experience of anyone running 175’s

[Keith Clements]

There has already been discussion on JT about fitting tyres and problems with rubbing at the rear and at the front.
At the rear you may get issues if the panhard rod does not keep the axle central and if your springs are not set up correctly or are weak or you have a large load in the rear.
At the front you may find the tyre rubs on the rubber boots of the early suspension (non-rubber)or on the wings if on full bounce or with weak springs or low set up height on torsion bars. The latter might depend on the chunkiness of the tyre. On one Monte Carlo rally we had to cut off the tread on the outside to stop the snow tyres rubbing.
I run Avon Turbo speed on the Javelin (and the SAJupiter with the SC having Pirelli DV86) and would not go back to crossplies. There is a light rub on heavy cornering with 3 in the back, so just take it a bit easier.
The issue is not about the speed you are cornering but the braking distance required in today's traffic where other drivers think you can slow down quickly. In the dry the radial probably has three times the contact patch and in the wet a modern tread pattern will get rid of the water more quickly.
But if you are only doing 100 miles a year in the dry and are an alert driver then perhaps consider crossplies as you will have none of the issues above.

[bobharvey]

I couldnt agree more - if I want speed I'll go in my IPace - jumping over catseyes, following linear road defects, and, as you say, braking, are the real safety issues. Ride comfort is usually better in my experience too. My ride height is standard and the car's a 52 so should be rubber bushed [having had Minors, Scimitars, and other rubber/Metalastik cars, I'm interested in the pros and cons of poly bushes, but that's another issue]

However I'd really like to hear from anyone running 175/16 tyres on whethere they've had any issues in practice. Whatever the theory, how it works on the car is the acid test.

[Keith Clements]

I ran King Pin 175-16 for many years on the Jup but they really need widened wheels to make them sit properly. On the Jav we and the other rally boys used them for rallying and my comments applied to using the King Pins as they sponsored us by supplying the remoulds. So you have the real world experience.
Fit the 165-16Turbospeed it is a brilliant tyre available through JCS.

[bobharvey]

The KingPins, like the other ‘taxi radials’ are 175/80 r16, which is what I’d initially been looking at, thinking the highest profile was the most similar to crossplies, but doing the maths, this produces an overall wheel diameter of 27”, compared with crossplies 5.25 which I measure at about 26.5. The turbosteels at 165x80 should be about 26.3.
Rather counter-intuitively, to me at least, 175/75 r16 gives 26.3 so might be better. I’ll talk to my local tyre guy about the rims.
I emailed Longstone about why their site says taxi tyres are unsuitable for classics and I’m afraid their reply was entirely insufficient to convince me to spend well upwards of £1000 on five turbosteels.

[Keith Clements]

I can understand the retiscence to spend that amount. The problem with 175s is that they are too large for the skinny rims. They are also designed for heavier cars.
Longstone are VERY respected by classic car enthusiasts. Believe me they KNOW what they are talking about.

[bobharvey]

A further problem surfaced on taling to my tyre guy - he says they used to fit tubes to tubeless tyre all the time if there was damage or poor seal but the newer tubeless tyres have an abrasive inner layer that chafes the tubes. He says it's not illegal to fit them but technically an offence if your stopped driving a vehicle with tubes in tubeless tyres.
The only radials rated as 'tubed' are the Michelins, the Avons are 'tubeless'
Needless to say the Javelin needs tubes as the rims dont have the bead retention profile present on tubeless rims.

[Forumadmin]

Try another tyre fitter and phone Longstone to confirm what your guy said.
https://www.longstonetyres.co.uk/classi ... tyres.html
Since all my 3 Jowetts have radials with tubes and have been for 50 years this must be a very new manufacturing process.
Note that extra strength tubes can be used and Longstone supply a rubber band to fit over the centre of the rim to protect against abrasion.
https://www.avontyres.com/en-gb/tyre-ca ... e-fitment/

[bobharvey]

From The MGA Guru:
On using tubes in tubeless tires, older tube type tires were nearly as smooth as a baby's bottom inside. Modern tubeless tires are not designed to have tubes, so there is very little attention paid to manufacturing them with a smooth interior. As such, you may expect to find a lot of raised molding marks on the inside, like a rectangular grid of small ridges. Tubes tend to squirm around inside of tires as they flex under load. The little rubber ridges inside the tubeless tire can eventually abrade the tube to cause stress cracks and pressure failure. If you will be using a tube, you would be well advised to run a power sander all around the inside of the tubeless tire to remove the molding flash and leave the inner surface as smooth as possible. And NEVER leave any manufacturer's stickers inside the tire if you will be using tubes.