Original tyres on TR5

[dougal]

Hi

Does anyone know what was the original tyre on a TR5?

I think it was 165-15 Dunlop SP41.

any thoughts?

Dougal

[andy thompson]

Or 165 x 15 Michelin XAS?

http://www.longstonetyres.co.uk/page/165hr15-michelin-xas.html

[dougal]

Cheers Andy, may i say what a great recomendation,

However was that what the TR5 fitted as Standard. i'm pretty sure the TR6 fitted XAS but i am unsure about the TR5 because i have found  an insurance book that says SP41 165-15 which is a period Dunlop radil tyre.

now i would fit XAS. the SP41 is no longer made. and the XAS is better.

[andy thompson]

Pretty sure XAS were optional on the TR5 - great tyres - used for production car racing at Bathurst too - went the distance with big V8's

[Tim Hunt]

Michelin XAS tyres were fitted to LHP 288F, one of the early road test cars as mentioned in the Motor test report in their edition of week ending 4th May 1968. LDU 158F was tested by John Bolster for the Autosport edition of 31st May 1968 and in August of the same year Motor Sport magazine used the same car over 2,000 miles in a hectic four days covering the Gulf London Rally. they were very taken with the car and particularly complimentary about the performance of the Michelin XAS tyres tyres in severe wet conditions. Whilst XAS tyres were certainly a factory fit on the TR5 I don't know if they were the only tyre fitted to this car from new or an optional extra.

The XAS was re-introduced for the classic market a few years ago but the price is absolutely eye watering!

Tim

[andy thompson]

https://www.youtube.com/watch?v=0vD_ja3addM#t=92

[piman]

Hello Andy,

he made an interesting point about fitting wide tyres spoiling the handling of the car, something I've felt for some time. Nice to see a specialist confirm it.

Alec

[andy thompson]

My white PI is on frankly ridiculously grippy 225/50 15 Yokohamas A050 which give probably close to the ultimate grip for a roadable car - but it handled much more nicely on cheapo 195/60  15 which probably had about the same grip as the original 185's

[piman]

Hello Andy,

yes, exactly.

I am old enough to remember the introduction of radial tyres and the general consensus then was that although they gripped better than cross plies, if they let go it was much harder to control the car. The age old handling versus grip scenario.

Alec

[dougal]

Wow. generally speaking from the Triumph fraternity people seem to want to over tyre their cars with modern rubber. I think TR2 & TR3 155HR15 Pirelli Cinturato (or XAS) and for TR4, TR5 & TR6 165HR15 preferably Michelin XAS.

More modern tyres have squarer shoulders which increase the violent brake away that you were talking about when discussing the difference between cross ply and radial. radials do brake away more violently, but the more modern the radial and the wider the tyre the more difficult it is to catch.

Fat tyres are for cars that don't loose traction. more modern cars that suit wide tyres have very different geometry and are mostly front wheel drive (yuk). Thet are not designed to be progressive. so as well as fitting the right size tyre, a period tyre that is designed to compliment cars of this period will also enhance the handling. But of course the other big attraction to wide modern tyres is they are cheap.

by the way, that is me in the video, sorry about the berry

here's another one. a TR2 on crossply racing tyres. just a shame about the driver.
https://www.youtube.com/watch?v=wWPRxT9jw1w

[Tim Bancroft]

Totally agree.

My GT6 is a fairly standard car that oversteers at the slightest hint of heavy footed throttle action (swing axles and roll oversteer), it demands smooth and progressive throttle pressure. I run it on 175/70 13 tyres, these in my opinion offer the best compromise between ride and handling. Owing to the tyres relatively narrow width, break away is at lowish speeds, therefore I do not need Jim Clark'ish reactions to catch her!. 185 or larger width will mean that break away will happen at higher speeds, and I for one will never catch the car as it oversteers into oblivion! As for low profile tyres on such a car, er, I am getting old and the old teeth will start to rattle out and the car will fall apart!

Generally, I think modern car owners are being conned by manufacturers. I drive a modern Mini Clubman Cooper SD (yes I know, why??!!!), a competent car that is unfortunately ruined by run flat tyres that have stiff sidewalls that then destroy the ride as they have no compliance and therefore feel every bump. Last night I drove back from deepest Wales along the A40 from Llandovery to Beacon to Monmouth, the road was wet (What in Wales, no sh*t) and the car turned in well but I did loose adhesion and had a moment or two gathering in understeer (geometry and heavy engine), simply solved by taking the foot off the gas for a second. What I should do is get some narrow 15'' wheels and fit a high profile narrow width tyre, reckon the car would then be a hoot!

Wide low profile tyres are not the way forward for old cars!

[69vitesse]

Your BMHT certificate will specify the tyres fitted at the factory during build.

[nang]

Thread drift sorry.
Andy,
Once bought an HQ 202 fitted with 205's . Rear wheel steering! Went back to 185's and all resorted to normal.
Tony.