Tyres....Radial, bias-ply or cross-ply?

[Michael D]

Here's that guy from Holland again and being the square peg in the round  hole that I am, here's another question.
My Rosengart will be delivered within a few days 
We renegotiated the deal when after three visits it was still hardly possible to testdrive it properly due to electrical glitches and a dying ignition. Eventually  it ran well in second and reverse (..sic..) but wouldn't really pull in first and third (me thinking it was an ignition issue). Steering and breaking were 'encouraging' (and a lot better than the Morris 8 two seater I drove last month)  notwithstanding bit of a bumpy 'n' shaky ride.
We managed to limp back to the verdor''s garage, complained, his mechanic came to show me how to drive properly (....) but by then no spark could be tempted to jump from the plugs any more (probably the coil was fried by jump-starting attempts two days earlier with a 12 volt starter battery......so we started twisting the vendor's arm as by then we were under the impression that more harm than good woud be done to the car by further attempts by the vendor and his team of mechanics ... So we bought it 'as is' and leave the cosmetic respray.. some people even say that being  brush-painted it has it's charms as well...

Anyway... the tyres - spare included - need replacing.. two old Firestones on the front, two Yokohama (...sic...) motorcycle tires on the rear axle and a crumbling spare  the rear deck... 

Now not being hindered by any knowledge or scruples I'm slitghly biased toward radial tyres (because of their presumed / assumed directional stability)  but non of my pre-war driving friends could tell me from their own experience (!!!) the. pro's and con's of either cross-ply or radials... They all just stuck to cross-plies (in some cases these extortionally Michelins...) and even not having driven  any of their prewar cars on radials they dismissed that idea at first. hand.

Now I'm considering Avon SM tyres  in 4.00x19 (as that's the size my rosengart should run on); they are radials according to Longstone (France) but I do not like buying in France as French suppliers take ages to ship and  they always use Collisimo.....expensive and still slow in delivery, track&trace stops working at Gare du Nord.....terrible .

Alternative might be the AvonAM7 Safety Mileage MKII's in 4.00x19  as they are available from another supplier at a better price, free shipping and delivery usually within 5 days....

Other alternatives: the Excelsior Comp and the Longstone, the tread pattern of the latter please me more plus the 'pedigree' of that tread pattern even though mine wil be no racing car.

So how. about your esteemed and much appreciated. opinion on this issue? I'm a newby in pre-war cars, so willing to learn..


BTW. I'm attaching a pic of the car... hope it'll appear.

 
  1444044813582934.JPG (Size: 123.24 KB / Downloads: 473)

[GK5268]

Nice car, my Ruby has period correct cross-plies (Longstone), never thought about radials, my 1965 daily driver has radials (Rover P6 - designed around radials) and when I got the car it had inner tubes fitted (not quite sure why), but steering was hard work, had them removed, improved no end. Last year, had to renew all tyres and I fitted period correct Pirelli Cintanturos (which hadn't been available at the last tyre change), transformed the car, handled like a little excited puppy dog, steering much lighter and quieter at speed. I had a Rover P4 back in the 1980's and the Club commissioned Avons to reproduce the original cross-ply tyres, a lot of owners had fitted radials, but with the good quality tyres, the car handled as it should, used to wander with the old tyres but with the good quality correct tyres the car was transformed.

For me, I get the tyres that the car was designed for and the best quality tyre I can afford as my experiences show that the cars are nicer to drive and I would not want to experiment with what is a fairly costly item!

[Steve Jones]

The Avon SM tyre is most definitely a cross ply, not a radial. However, whilst they've been used by many A7 owners for many years, they're a motorcycle tyre, not a car tyre. The two have different design characteristics and now that such as the Longstone and Blockley cross ply tyres, designed specifically as car tyres, are available, to me the choice is obvious. I have Longstones on all my Sevens and would never change back. Whilst Longstone do have a French web site, they are not located in France. Any tyres ordered would come from the depot in South Yorkshire and they have quite a reputation for getting tyres to customers world wide very quickly. Longstones every time for me.

Steve

[Reckless Rat]

I can back up what Steve has said. I live in France and ordered Longstones from the .fr website. They were delivered direct from the UK and arrived very quickly.

[Michael D]

Thanks, gentlemen. As yet the balance is tipping towards Longstones.... the fact that they were designed for cars and the AVONs for motorcycles does tend to be a convincing argument....

[Reckless Rat]

The Avons you should use have "Sidecar Triple Duty" on the sidewalls and have a different profile from normal motorcycle tyres, which are rounded. I used to use Avons but like the Longstones better. Mitas used to sell a tyre similar to the Longstones but Im not sure they are still available. Longstones recommend higher tyre pressures than Avons. I run mine at 30psi (1.8 bar). I saw a car loke yours at a local old car run. His was a 6 cylinder but basically the same.

[Michael D]

The Avons you should use have "Sidecar Triple Duty" on the sidewalls and have a different profile from normal motorcycle tyres, which are rounded. I used to use Avons but like the Longstones better. Mitas used to sell a tyre similar to the Longstones but Im not sure they are still available. Longstones recommend higher tyre pressures than Avons. I run mine at 30psi (1.8 bar). I saw a car loke yours at a local old car run. His was a 6 cylinder but basically the same.

Mitas tyres are available but the tread does not look like Longstone / Blockley to me and it's also marked as being a motorcycle tyre (Like the Avon SM...) https://www.vintagetyres.com/shop/tyres/...6&search=1

Wow..someone fitted a 6 cilinder to a Rosengart LR4N2?? he must either be a brave man of have done some hefty mods to chassis / suspension and braking as well.... would like to see more that BTW....

[Chris Garner]

I think the car Reckless is referring to would have been the six cylinder 1097 cc 25 hp model, introduced in 1932

[Reckless Rat]

This is the 6 cylinder Rosengart:
- apparently the model number is LR70 from 1938.
It lives near Avignon.

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More photos:

[Michael D]

Ah well. yes. that figures.. a factory Rosengart 6 cyl.....quite a different beast

back to the tyres issue: Blockleys show just about the same tread as Longstones but cost 25% less, so when buying five Longstones would cost me £ 505 ex VAT and Blockleys £ 375 that's a difference in the outlay I can put to good use elsewhere on the car.. So what's the justification for that price difference?? are Blockleys below par tyres made somewhere in an obscure factory in a low wages country or is Mr Longstone just buying in at the same factory and simply charging more for the same product?