Tyre sizes

[robbiesmith]

Okay folks, advice please.

My little treasure (1969 Traveller) has 145/14s on the front and 155/14s on the rear. The spare is a 145/14 (with an inner tube!).

What would you do?

[melanddoug]

Strangely, I have exactly the same situation. On a Traveller. A white one.
I have 155 on rear/ 145 on front (owing to some inherited wheel randomness)

I've been advided by one dealer that 155/14 are cheaper because they're easier to find, and that seems to be true looking at ESM etc, so I'll probably go with 155.

[d_harris]

You've swapped the wheels then Doug?

Apparently the Bridgestone 145s that you get now are pretty pony.

[bmcecosse]

Go up to 155s when the time comes - run them at ~ 34 psi.

[charlie_morris_minor]

Go up to 155s when the time comes - run them at ~ 34 psi.

you did recomend 30 psi why the increase to 34 psi.. is it inflation

[melanddoug]

Dan - yep, mainly as an experiment really. I liked the Wellers - excellent cornering! And I liked the look too.

Unfortunately, the roads round my way are *awful* - patchwork and potholes everywhere, and loads of speedbumps, resulting in a v bumpy ride and associated chipped teeth. I tried some standard wheels to see what would happen and the ride was SOOO much better, and the bigger size = better cruising @ 60 or so. Monty's going superbly now (changed the head gasket- virtually all rough engine probs disappeared) and he's so far serviced 2 gigs filled with band gear

I didn't know the pressure should be 34 PSI though - mine are at 28. Better get to the air pump!

[d_harris]

Fantastic, I'm glad that everythings worked out That said, I'm really suprised that the HG was to blame - I seem to recall that it was a good quality copper gasket that went in...

Edit: If you did want to keep the wellers and get a bit more cushioning - ditch the low profile tyres and fit 175/80/13. Virtually identical rolling radius to 155x14

[Kevin]

Go up to 155s when the time comes - run them at ~ 34 psi.

you did recomend 30 psi why the increase to 34 psi.. is it inflation

It must be, as that seems high to me.

I didn't know the pressure should be 34 PSI though - mine are at 28. Better get to the air pump!

I wouldnt worry I have used 28psi on saloon's and 30psi on Travellers and all has been fine with even wear.

[rayofleamington]

my preference is 145's as they behave much better in heavy cornering, but the difference to the average driver is very small.

28 to 30psi on a soloon gives a reasonable ride, and going higher will case the centre of the tread to wear more - which itself proves that the tyre is not giving an even footprint (i.e. less grip)

[chickenjohn]

I also inflate to 30psi and would suggest getting the thinner size tyres. From driving my Minors, it seems a 155 section is just a bit too wide for the Minor rim and the weight of the car. My Traveller corners and steers much nicer with 135 tyres on the front axle.

I think 135's (sadly no longer available for 14" wheels) are the ideal size for the Minor, 145's the closest we can get to with current tyre supplies. It is a bit of a common misconception that wider tyres are better- not so! (possibly a myth of "boy racer" origin).

[robbiesmith]

Thanks folks, although there seems to be a lot of conflicting advice here I think a pattern is emerging.

My handbook states 145 OR 155/14s (which is why I asked) and it seems that it would not be possible to discover what was OE back in 1969. The Rolling Radius of the two sizes is very close - close enough to be totally legal and safe. The effect on speedo accuracy would also be negligible so it appears (reinforced by all your opinions) that there is no 'right' answer, but that it is all a matter of taste really.

As to pressures, though, the handbook states 22psi front and 24psi rear. This is a huge difference from 34psi all round and still significantly different from 30psi or even 28. Which leaves me wondering why.

I will have to sort things out, though, as running on a 155 on one side and a 145 on the other on the rear axle after a puncture sounds a shade dodgy (especially as my tubeless spare 145 appears to have an inner-tube).

I'm currently running on the recommended pressures, although they do look a touch 'squidgy' even for radials. You people certainly know your stuff so there must be a good reason for inflating the tyres to much higher values and more information on this issue would be greatly appreciated.

Thanks again.

[PSL184]

Original spec was 5.00x14 crossplys which is why the handbook states 22/24psi. Radials need to run at higher pressures because the sidewalls are weaker. Nearest modern equivalent to 5.00x14 is 135/80 R14 but these are no longer manufactured unless special runs are made of them (and very expensive). Nearest sensible modern size is 145/80 R14. Tyre pressure is dependant on your level of comfort and load carried so start at 28 psi all round and increase slightly if it feels too squashy. But dont go more than 32psi.......

[robbiesmith]

That looks like sense, I think I'll put a bit more air in my tyres, replace the 155s and the dodgy spare with new 145s and see how we go.

Thanks everyone for your help.

[charlie_morris_minor]

a word of warning i purchased bridgestone 145 a few years back and found the ride terrible as the side wall was very soft, which had been bullmotif's big selling point

i find the 155 give a nice positive ride when running at 30 psi, if you live local, to me, you are more than welcome to do a tyre swap, for a test drive with toyo 155's before buying some.

[robbiesmith]

That's a very generous offer, Charlie, I think I'll avoid Bridgestones then. I'm down on the Sussex coast, so a bit far away.

Thanks for the warning.

[aupickup]

i went to buy some tyres yesterday
i looked at the bridgestone ones as they were 145`s, but went for the new style nankang ones tho they were 155`s
the ride is good on these ones, only had them on the front, but were very good

i had marshalls 145`s all round, and they were a good tyre, but unavailable now

[mike.perry]

The higher the tyre pressures, the harder the road humps

[Alex'n'Ane]

Please explain the disadvantage of 155's over 145, i thought 155's would allow a greater contact patch so better grip?

[d_harris]

The problem with the 155s is that being a little wider theres the potential for a little more "roll" in the sidewalls when under lateral forces.

You'd need to be driving like Stirling Moss to realyl notice though...

[IaininTenbury]

I'll probably get 155s to replace the elderly 145s onmy convertible in the spring solely due to how it looks as the larger tyre fills the wheel arch a bit better and is closer to the height of a high profile 520/14 crossply. Probably more noticable on a Series 2 with the higher cut rear wings.
I'm running a set of 185/13s on white 8 spokes at the moment as a cheap (they came on a car I once had) stand in and had to reduce the pressure to about 24psi to get a comfortable ride. Handles well though, was pulling away from a Porshe 911 on a favorite twisty bit of road though oddly he caught me up on the straights! Look forward to going back to standard rims though as the usual question has changed from "how old is it", and "my (insert relative of choice) had one of those" to "what engine have you got in that then?"

Presumably you can run slightly lower pressures with 155s than a 145 as the weight is spread over a wider area and would then give a more comfortable ride, though as Dan says, they're so similar you probably wouldn't really notice.