The Triumph Dolomite Club - Discussion Forum

DavePoth wrote: Your insurance company will not see it that way. If your tyre pressure is wrong and you have an accident they may decline to pay out because you have made an unauthorised and dangerous modification.

think im screwed if i need to claim regarding mods
Seriously though stick to recommended pressures

The reason why the steering lightens is because the tyres overinflate, balloon and thereby leave less tread in contact with the road.

Granted. This is the first thing I looked at after pumping them as I've driven behind cars that looked liable to flip over if they hit anything the tyres were that hard but the dolly's tyres are flat to the road and if anything still have some give. I wouldn't drive on them without it but 22/24 leaves them looking very flat, hence the tough steering when parking etc. I'm going to have the car checked over soon enough so I'll make sure the steering is looked at just to be on the safe side.

Garfin wrote:

The reason why the steering lightens is because the tyres overinflate, balloon and thereby leave less tread in contact with the road.

Granted. This is the first thing I looked at after pumping them as I've driven behind cars that looked liable to flip over if they hit anything the tyres were that hard but the dolly's tyres are flat to the road and if anything still have some give. I wouldn't drive on them without it but 22/24 leaves them looking very flat, hence the tough steering when parking etc. I'm going to have the car checked over soon enough so I'll make sure the steering is looked at just to be on the safe side.

As I mentioned above, if you are driving more than a couple of miles to a garage to pump them up the warm pressures are more like 26-27 front and 28-29 rear anyway.

Blimey...!!! I am sorry to drag something up so distant but I do have to say something about tyre pressures as discussed on here...

Reading an old copy of Motor (from 1974) about their long-term test Sprint they said the pressures should be 22/24 but for me that is far to 'squidgy' as it were...

First of all, even if I was to stick with those pressures I'd have to put the higher bias on the front as they (in my mind) need to be a tad firmer for steering duties surely...?!

Anyhow, I run my Sprint rimmed Toledo at 28/26 as that is how I feel it is at its best (for me) and I could even imagine running at the factory approved pressures!!!

Again, I am sorry to drag this up but I just thought I'd throw my opinion into the mix!

My Haynes manual says 26/30. Just saying......

^ That's for an 1850.
22/24 is good for grip but response definitely lacks. I settle for 30.

I was running my sprint on 185x60x13 and a tyre that was not available back in their day, I ran them at 26 front 30 rear and a well known Dollie guru at Mallory told me to swap them round and have more in the front.
In my case I ran 30f 26r and the car handled a treat, more to the point is the fact that if you hit a pothole with a measly 22 in the front you are most likely to puncture the tyre.

Why follow what the factory stated all those years ago when they clearly got a lot wrong on our cars elsewhere.

Just to prove a point these are what the factory got wrong.
Timing
cooling
brakes
rack mounting
some axle locations
headlight switches (no relay)
engine mounts

However its still a great little car

I am so surprised that the 'heavier' bias is towards the rear of the car when surely it should be towards the front in order to get a more direct feel from the steering wheels...?!

I suppose there must be a good reason but I'll be jiggered if I can figure it out...!!!

Dolly-Nut wrote:^ That's for an 1850.
22/24 is good for grip but response definitely lacks. I settle for 30.

The manual covers the 1850 and the Sprint and doesn't differentiate on pressures.

Insurance assessors don't check tyre pressures,they are much too idle for that! the only time they are likely to be checked is if a fatality is involved and the police engineers check the car.
God knows what they'd say about mine which is running 195/50/15s instead of the 155/80/13s it left the factory with! And in case you're interested, that combo works best at 26 front, 22 rear (cold).

Steve

I've just taken my SPRINT out for one last shake down cruise before my big Easter trip.
Before I left I let the tyre pressures down to what the book says, 22psi front and 24psi rear, cold. (175/70R13 Yokohama A drive's.)
I did this because last weekend I travelled about 160k's with them at 28 front and 26 rear (where I've always had them) and found the car to be really skittish on uneven bitumen etc. (ah, New South Wales, the State of the Roads) and the ride generally harsh.
With these book recommended pressures, its become a different car and is now even more of a pleasure to drive. I LOVE it and its where these pressures will stay.
Cheers,
Rob

I fitted new Avon ZV5's two years ago and have run them as per Triumph specification. Right now I'm ordering four new tyres as the side walls have cracked badly.
I have no means to determine whether the damage is related to running the tyres at less than their optimum design pressure. I have no intention of fitting a second set and running them at the same pressure to find out. Whatever the issue, they're buggered after 5k miles!

The discussion over tyre pressures is a little ambiguous. The reason being that tyres of the 1970's will have had vastly differing compound properties compared with modern tyres. So its not a case of running a modern tyre at the design pressure of a 1970's tyre, its about running a tyre within its design pressure tolerance. Compare with running an appliance with the wrong fuse!

If you are worried about this you simply tell your insurer that you are running tyres than are the modern equivalent of the original tyre. Its quite clear that you cannot get the original factory fitted tyres or any equivalent tyres with a date stamp 1977, for example.

Well say what you like I cannot agree with the main on this.
There is no manufacturers pressures applicable because 60x185x13 were not fitted to sprints hence I really do not think an insurance company would bother with pressures unless they were miles off.
So I liked 33 front and about 26 rear using 185x60x13" rubber on mine.
These days there is another factor to take into account and one that was extremely rare 20 years ago, DAMN POTHOLES, our third world roads are terrible and a soft tyre is vulnerable when hit by them and a few pounds extra help.

I'm after the following info, then the tyre manufacturer will recommend the pressures: (I'm away from home, so don't have manuals).

Maximum speed: Km/h

Max weight of front axle kg

Max weight of rear axle kg

Wheel rim size

If people could post this data for 1850 and Sprint that'd be brilliant, they've promised a prompt answer.

matienzo wrote:Right now I'm ordering four new tyres as the side walls have cracked badly.

I would not be buying new tyres until I had complained strongly about this.

If it was due to tyre pressures then we would all be having this problem.....?



Ian.