[joslicx]

Of late I have been wondering about this question about changing tyres on my '12 Vento. I am running on Michelin Primacy3s that I got some 7+ years back during the last change. Since then they have done about 28k km. Am extremely happy with the tyre. Have not even had a single puncture during this time. The only reason I am thinking of change is I am not sure what kind of effect time has on tyre rubber itself and whether it is still ok to keep using these types for another 1-1.5 years that I intend to keep my car. My running is not that much and almost exclusively in city only. Would these tyres still be ok to use for another year or so?

[sagarpadaki]

Originally Posted by joslicx

Of late I have been wondering about this question about changing tyres on my '12 Vento. I am running on Michelin Primacy3s that I got some 7+ years back during the last change. Since then they have done about 28k km. Am extremely happy with the tyre. Have not even had a single puncture during this time. The only reason I am thinking of change is I am not sure what kind of effect time has on tyre rubber itself and whether it is still ok to keep using these types for another 1-1.5 years that I intend to keep my car. My running is not that much and almost exclusively in city only. Would these tyres still be ok to use for another year or so?

I remember reading an article by michelin where it said that the tyres can be used upto 10 years from the date of manufacture as long as the are not damaged or runout.

[VWAllstar]

Originally Posted by ashis89

Let me ask this question again - When is the right time to change the tyre?

Thanks for asking this question. Most posts deviated from the actual purpose of the thread.

No scientific study behind this, however I prefer to change all 5 tyres every 5 years or 50K KMs whichever is earlier. Every yearly service, the tyres are evaluated for Tread Wear and accordingly decide for the next course of action.

There are many probabilities and theories, however sticking to changing tyres every 5 years or 50K KMs is a good practice. Many performance tyres should be changed every 3 years or 30K KMs depending on the use case.

[zeng]

Originally Posted by sagarpadaki

I remember reading an article by michelin where it said that the tyres can be used upto 10 years from the date of manufacture as long as the are not damaged or runout.

10 year tyre life from the date manufacturer is a' 'standard' specified tyre life in manuals (I've come across) of 'branded' tyre manufacturers all across the globe.

[zeng]

Originally Posted by joslicx

Of late I have been wondering about this question about changing tyres on my '12 Vento. I am running on Michelin Primacy3s that I got some 7+ years back during the last change. Since then they have done about 28k km. Am extremely happy with the tyre. Have not even had a single puncture during this time. The only reason I am thinking of change is I am not sure what kind of effect time has on tyre rubber itself and whether it is still ok to keep using these types for another 1-1.5 years that I intend to keep my car. My running is not that much and almost exclusively in city only. Would these tyres still be ok to use for another year or so?

You can safely run or operate up to 10 years from manufacturing dates, according to tyre manufacturers.

Originally Posted by ashis89

Let me ask this question again - When is the right time to change the tyre?


1. After certain KMs of usage?

Short answers (according to tyre manufacturers manuals on after market tyres)
No

2. After certain years of usage?

10 years for after-market tyres from 'branded' (western/Japanese) manufacturers.

3. When the thread reaches the tyre wear indicator?

On tread groves depth reaching 1.6 mm, as shown in Tread Wear Indicators within the grooves

4. When the additional thread markings are worn out?

??

5. When you feel the need for a change (high tyre noise, frequent punctures, loss of grip)?

Feels isn't stated as a criteria in manuals.

[AJ56]

Originally Posted by PistonCrown

I have a query.

The tire cracks seen on tires, which are relatively common between 2-4 years and within 50% of wear on
(i) main tread areas
(ii) sidewall

Are they considered under warranty by tire manufacturers??

Also, should that not be covered by manufacturers, as cars are meant to be on the road and this scenario is not something induced by any car owner?

I’ll assume the cracks being referred to above are dry rot, doesn’t happen in 2 years though. 4-5 years if you’re parking in direct sunlight for long periods, it will happen irrespective of how much you’ve driven.

It’s not covered under warranty as it’s perfectly normal for rubber tires to lose oils and develop minor cracks once near their end of life (around 5 years in most cases.) Specially if you don’t drive much. Old, hard tyres are a major safety concern as they don’t grip the road as well, if you see dry rot, get new tyres.

The late Paul Walker died as the Porsche his friend was driving lost grip mid corner as it had 8 year old tyres.

Originally Posted by ashis89

Let me ask this question again - When is the right time to change the tyre?


1. After certain KMs of usage?

2. After certain years of usage?

3. When the thread reaches the tyre wear indicator?

4. When the additional thread markings are worn out?

5. When you feel the need for a change (high tyre noise, frequent punctures, loss of grip)?

1) No limit, as long as you have more than 2mm of tread depth left (check wear indicator on tyre or use a tread depth gauge like I do).

2) Yes, rule of thumb is 5 years. If you don’t get dry rot you can push to 6 years but the rubber gets hard and the tyres don’t grip very well and ride quality also goes for a toss.

3) Tread depth levelling with the wear indicator is the last resort, ideally do it with an extra 1mm left as in the wet, a tyres ability to evacuate water from the grooves is greatly compromised when near its end of life tread wise.

4) Additional thread markings?

5) Yes, this is subjective but you can if you feel the rubber has become too hard for your liking even if the hard limits above aren't reached.

All in all, always err on the side of safety with tyres (and brakes), it’s the only point on contact our entire car has with the road and given they’re relatively cheap (4-5 tanks of petrol) even for the best Michelins, it’s a no brainer. (I’m aware performance tyres run into lakhs, talking 40-50k for regular, non performance cars like a Camry)

[ashis89]

Originally Posted by zeng

??

Originally Posted by AJ56

4) Additional thread markings?

I was referring to the thread patterns which are not indicator deep.

See this new tyre



And this 50k+ run sample. The depth indicator within the red circle shows lot of thread left but the other thread patterns are worn out. The lack of those patterns would also make significant difference in grip levels, isn’t it?

5) Yes, this is subjective but you can if you feel the rubber has become too hard for your liking even if the hard limits above aren't reached.

All in all, always err on the side of safety with tyres (and brakes), it’s the only point on contact our entire car has with the road and given they’re relatively cheap (4-5 tanks of petrol) even for the best Michelins, it’s a no brainer. (I’m aware performance tyres run into lakhs, talking 40-50k for regular, non performance cars like a Camry)

If one is driving only one car, there’s no frame of reference to know how good and bad their car’s tyre is. One day one incident will tell them that the tyres are not up to the mark anymore. But that incident could come a little too late too. Hence the point of the query on this thread.

Btw a good tyre will cost 2-3 tankfuls of fuel. A set would be 10-15 tankfuls worth. Not an easy decision to chuck an old set if they’re still good.

[AJ56]

Originally Posted by ashis89

I was referring to the thread patterns which are not indicator deep.

The lack of those patterns would also make significant difference in grip levels, isn’t it?

There’s no frame of reference to know how good and bad their car’s tyre is. One day one incident will tell them that the tyres are not up to the mark anymore. Hence the point of the query on this thread.

Tyre tread is only for grip during wet weather, during dry weather, slicks (tyres with no tread) will grip better, as the tyre surface area in contact with the road is maximised. This is also why race cars always use slicks in dry weather.

Without tread, you won’t have any grip in wet conditions which is why it’s vital on road cars. I don’t think the micro treads you’re referring to have a major impact on wet weather grip, you can shoot an email to your tyre mfg just to confirm.

If you drive the car often enough, you’ll be very much aware of tyre degradation during aggressive corners or hard braking vs when they were new. Grip will be noticeably lower, if you want an objective test, find a closed road/track and simply measure the distance it takes from say 60 to zero.

Perform this test when tyres are new and when you feel they’re losing performance, ensure tyre and road surface temperatures are roughly the same for consistency.

Originally Posted by ashis89

Btw a good tyre will cost 2-3 tankfuls of fuel. A set would be 10-15 tankfuls worth. Not an easy decision to chuck an old set if they’re still good.

4-5 tankfuls for all four. I’ll take my own example, Michelin Primacy 4’s I picked up recently for my Camry were 37,500 inc gst. Camry has a 75L tank, petrol is 102/L. 102 x 75 = 7,650 per tank or 38,250 for 5 tanks or a little over a month of driving. So tyres were 4.9 tanks of fuel.

If you drive a sports car, these numbers will be different no doubt.

[zeng]

Originally Posted by ashis89

I was referring to the thread patterns which are not indicator deep.

See this new tyre
Attachment 2755578


And this 50k+ run sample. The depth indicator within the red circle shows lot of thread left but the other thread patterns are worn out. The lack of those patterns would also make significant difference in grip levels, isn’t it?
Attachment 2755579

The disappearance or smoothening out of both small circles (of about 6-8 mm??) as well as narrow shallow groves as pictured in this 50k usage tyre is not a criteria on recommending tyre replacement.

Grip?

Everything else being equal,. grip is lost progressively on wet road surface from marginal to severe level as degree of wetness increases.

On dry road surface grip level improves, albeit marginally.

Edit:
Your vehicle seems to have a rather good alignment #s, delivering good wear rate and quite even wear pattern between insides and outsiders.

[self_driven]

Originally Posted by ashis89

And this 50k+ run sample. The depth indicator within the red circle shows lot of thread left but the other thread patterns are worn out. The lack of those patterns would also make significant difference in grip levels, isn’t it?

Hi,

The small slits encircled in blue are called sipes. These are an integral part of tread design for road tyres. Besides controlling road noise and vibrations, tyre sipes aid in faster water evacuation for better wet grip and provide air channels for improved heat dissipation in dry conditions. Only a tyre design expert can comment on the technical details and how things work. The key takeaway is that sipes do have a role to play in tyre performance, although their role is not as significant as deeper grooves in the tread. Hitting TWI in the grooves indicates that the tyre has reached the end of life where grip can be compromised to an unsafe level, while in actual the degradation and "compromise" begins early on and happens gradually as the tyre wears out.

A tyre with worn out sipes will not perform according to its peak potential, similar to how a 50k-driven tyre halfway through its life will lose grip faster than a brand new tyre in extreme conditions, or how a tyre's shock absorption capabilities go down as it dries out, or how they become noisier as they age. It is up to an individual's tolerance levels and their risk appetite to decide when the tyres need replacement, besides TWI and other visual indicators such as dry rot or cuts. Worn out sipes are not a criteria as their role is insignificant for most users in comparison to deeper tread grooves.

Btw a good tyre will cost 2-3 tankfuls of fuel. A set would be 10-15 tankfuls worth. Not an easy decision to chuck an old set if they’re still good.

True. My Endeavour's full tank costs under Rs. 7000, while the most recent tyre change set me back by 70k. For me, it was a significant amount to spend on the car, but this is probably the last set it requires based on my limited usage. It ultimately boils down to an individual's disposable income.