Tyre Hardness

Both my Alpines (110 and 310) have Advan R-Spec tyres on them (for various reasons I won't go into) and my Delta Integrale has Advan AD09 (almost R-Spec)......obviously all are pretty soft compound and the cars are driven one or two times per month and are kept in garages under covers the rest of the time. I've noticed that they all still have softness (the finger nail test), so I reckon they will easily go 10 years at this rate (maybe more??). The A110's A048's have been on over 5 years so far.
I think the initial softness of compound, no track work but "regular" road driving and kept in a cool place under cover will keep them in good shape.
 
Sunroof said:
Got a tyre hardness meter. Take 6 or more readings around tyre and on different sides and centre of tread. Then average the result. It is interesting to note that the hardness varies quite a bit around the tyre.
Some examples.
Vitoria City Life 7 years old 165 X 13 on front of R10 hardness 71.
Nankan 9 years old 145 X15 just removed from Floride S but kept as spare. Hardness 61.
Vitoria Work Life unused trailer tyre 175 X13 2023 manufacture. Hardness 58. Had the biggest variation around the tyre.
Michelin MXL 175 X 13 no date probably 20 years old on R15 off road for 12 years. Hardness 67.
Michelin Pilot 3 195 X13 of Fuego not registered. 15 years old but was used on the track. Hardness 89.
None of the tyres have done many kilometres as on old cars on club registration. None show any cracks. But some not used for some years so if put back on road who knows.
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Now I have to buy a hardness tester!! Live and learn - I didn't know you could get such things. Thanks for this!
 
So if hardness equals more kilometres the soft equals better grip then because old classic cars don't usualy do large kilometres it would be best to buy soft tyres to take advantage of grip rather than throw away a tyre with plenty of tread but has reached its use by age.
 
But why would the softness of the rubber determine whether the tread delaminates (or not)?
 
I decided to check my Landrover Cooper tyres. Cooper insist their tyres are good for between 80,000 and 100,000 kilometres. A quick check of their web site has no mention of tyre age as a problem. What they say is that braking grip is reduced as the tyre wears. They "imply" that the Australian standard of 1.6mm of tread is not enough. They seem to only suggest wear as a reason to change tyres. Cooper Discover SR 2019 hardness average 65.
 
Armidillo said:
But why would the softness of the rubber determine whether the tread delaminates (or not)?
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I don't think it does. This is mixing up grip, especially on wet roads, with tyre structure. I just put now Michelins on our Renault Scenic because wet weather grip was deteriorating badly. The tyres were only about 7 years old.
 
Sunroof said:
I decided to check my Landrover Cooper tyres. Cooper insist their tyres are good for between 80,000 and 100,000 kilometres. A quick check of their web site has no mention of tyre age as a problem. What they say is that braking grip is reduced as the tyre wears. They "imply" that the Australian standard of 1.6mm of tread is not enough. They seem to only suggest wear as a reason to change tyres. Cooper Discover SR 2019 hardness average 65.
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That's interesting. Braking deteriorates with loss of tread (less flex in the tread pattern as it gets thinner, so less conformity with small irregularities so less grip)? Of course as tread gets thinner the tyre is older too.

I agree that by the legal tread limit, a fair bit of wet weather grip has been lost.
 
Glenn Drake said:
My experience is a set of Michelin XVS at 20 years old and 15,000 km.
I knew they were getting hard by the way they thumped over any small bumps.
One day travelling at 90kmh one simply flew to pieces on the freeway. It literally just broke up.
New tyres all around after that as I could never relax driving the car waiting for another tyre failure
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Armidillo said:
But why would the softness of the rubber determine whether the tread delaminates (or not)?
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Sunroof said:
No idea, I don't think it does.
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Ok - in typical Aussie Frogs style, 2 (related) subjects have been woven together into a single thread. It would be nice if the hardness meter could predict the risk of tyre delamination.
 
Armidillo said:
Ok - in typical Aussie Frogs style, 2 (related) subjects have been woven together into a single thread. It would be nice if the hardness meter could predict the risk of tyre delamination.
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I doubt it - different matters, although both age-related. I guess if you had a plot of hardness versus time and hardness reached a maximum at some value you'd know you'd reached the bottom of the curve regarding grip. Time to change tyres anyway?
 
The small contact patches of rubber are all that is keeping you alive
Spend money on new tyres and forget the hardness tester.
Forgo the graphs, numbers and charts.
You can spend all your time working the maths when you are 2 metres ( 6ft ) under.
This is a metric Blog website of course
 
Coopers guarantee their tyres for 80,000 kilometres. The only age related proviso is that for sun damage cracking and it is 4 years. Obviously there are other provisos relating to use and maintenance. An inspection is required every 10,000 kilometres.

Worn tyres also take longer to stop. Tests carried out by independent experts at the Motor Industry Research Association in the United Kingdom demonstrate that reduced tread depths dramatically increase a vehicle’s wet braking distance.


Body-img_tread-VS-braking_500x350px-4.jpg


Coopers have car tyres but only in big wheel sizes starting at 16 inches and going up to 19 in most sizes. I think I'll try them when I next need tyres for the Latitude. My Land Rover tyres are very quiet.
 
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driven said:
The small contact patches of rubber are all that is keeping you alive
Spend money on new tyres and forget the hardness tester.
Forgo the graphs, numbers and charts.
You can spend all your time working the maths when you are 2 metres ( 6ft ) under.
This is a metric Blog website of course
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Funny, using that exact logic we decided recently to put four new tyres on the #3 Scenic! Should happen Wednesday.

I'm interested in the hardness though.
 
Three observations:

First, the importance of tread depth is a function of the water depth used in the wet braking test. Most tests that report such depths are using a depth that wouldn't (short of a puddle in a depression) occur on an Oz cambered road. On our roads (& speeds), aquaplaning is not so much the danger as compound engagement.

Second, surface hardness is not directly connected to delamination. What is crucial for the latter is the belt/"rubber" bond; although "rubber" flexibility retention is important here, the impact of some environmental "insults" on the tyre is different at the tread to deeper in.

Third, tread element deformation under stress is not a merit for any aspect of type performance.
 
Two observations pertinent to above post.

here in Sydney metro, for whatever reason, probably poor road foundations, you end up with a road that has two grooves per lane corresponding to where the trucks drive.
Water pools nicely in these.

Secondly, I suspect the contracts, budgets and schedules for vegetation removal from Sydney’s storm water systems were drawn up in a drought, because they are massively inadequate when we get a tropical style rain event, especialy one in autumn.

i remember when Roseville bridge flooded a while back thinking F## me dead, that is 11 meters above sea level.
Of course it wasn’t that type of flood at all, just some palm fronds etc clog up the storm water drainage system and a sizeable enough road catchment to cause grief.
as far as my 54 year old memory goes, that was the first time this road had flooded.

these events are becoming more common unfortunately.
 
jo proffi said:
Two observations pertinent to above post.

here in Sydney metro, for whatever reason, probably poor road foundations, you end up with a road that has two grooves per lane corresponding to where the trucks drive.
Water pools nicely in these.

Secondly, I suspect the contracts, budgets and schedules for vegetation removal from Sydney’s storm water systems were drawn up in a drought, because they are massively inadequate when we get a tropical style rain event, especialy one in autumn.

i remember when Roseville bridge flooded a while back thinking F## me dead, that is 11 meters above sea level.
Of course it wasn’t that type of flood at all, just some palm fronds etc clog up the storm water drainage system and a sizeable enough road catchment to cause grief.
as far as my 54 year old memory goes, that was the first time this road had flooded.

these events are becoming more common unfortunately.
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Australia-wide, culvert design is often inadequate. You should see the Pilbara railways... There's a lot to be said for fords. :)
 
Or the Finke River crossing on the Old Ghan railway line - didn't matter what they built, eventually it would wash away. Only really solved by completely rerouting the line into much drier areas further West.
 
Armidillo said:
Or the Finke River crossing on the Old Ghan railway line - didn't matter what they built, eventually it would wash away. Only really solved by completely rerouting the line into much drier areas further West.
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Yes, basically they put it broadly on the drainage divide instead - I did some work on that job. Of course the original line was for steam engines and it followed the springs around the Great Artesian Basin margin, like John MacDouall Stuart and the Overland Telegraph.
 
JohnW said:
Re age and hardness, I always get the best of my old tyres rotated onto the spare when getting new ones.
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Same, even when the guy at the tyre shop says "#$&@! These haven't been made in more than ten years!" 😲
The old Pirelli still had good even tread, keeps pressure, and in the event of emergency only needs to get me a short conservatively travelled distance.
 
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