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Old 2nd October 2016, 17:39   #1
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Default Tyre life: Monocoque vs ladder-on-frame cars

I am always surprised to see a Swift or any other hatch weighing maybe, some odd 1000 kgs has very less or no treads after logging in only 40,000 kms, make it 50,000 with careful driving & timely WA & WB.

Whereas have seen lots of Scorpios, Fortuners [all weighing close to 2 tonnes] having decent tread depth [if carefully driven] till 70,000 kms.

Why this happens?
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Old 2nd October 2016, 17:53   #2
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Without any facts to back up my assertion, I've two theories:
  • I've not observed this myself, but apart from frame vs. monocoque, the other differentiator is FWD vs. RWD. What if its weight of the engine sitting over the driven wheels?
  • The other factor I would think of is that car manufacturers often under-tyre their cars in the quest for mileage - OEM tires normally come between 155 - 175 mm width for mass-market hatchbacks. The big vehicles you refer to often come with 'right sized' tyres.
  • Tougher tire construction on the SUV type vehicles, as opposed to hatchbacks.

Last edited by arunphilip : 2nd October 2016 at 17:55.
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Old 2nd October 2016, 17:53   #3
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It could be that A/T Tyres found on fortuner and the like have deeper tread compared to normal road tyres. Also bigger the tyre the lesser the rotations it requires to cover the same distance. Both scenarios help retain tread depth in SUV's compared to smaller hatchback standard tyres.
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Old 2nd October 2016, 21:00   #4
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Quote:
Originally Posted by Sheel View Post
Why this happens?
Interesting question. Simple answer. Multiple reasons.

- Bigger circumference
- Thicker tread depth
= Wider tread
- Harder compound
- Lesser power-to-weight ratio
- Lesser alignment errors developing due to heavier suspension components
- SUVs are less sportily driven than hatches and sedans
- Driving and braking wheels are often different in SUVs (XUV5oo tyres don't last as long as Scorpio tyres, as I understand.)

That said, I've used Ceats on my Indica for 70+k km once (hard compound but terrible grip), and the Goodyear Duraplus on my Swift are at 52k km with ~30% tread depth still remaining. My Scorpio's OE BS Dueler 684s have worked for ~100k km on an average, and the current set (2 BS Duelers and 2 Ceat czars) have run ~45k km with good tread depth still remaining (the Ceats worn a little more than the Bridgestones).
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Old 2nd October 2016, 21:10   #5
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Definitely its the usage of harder compound on the body-on-frame chassis vehicles. After all, they have to carry 1.8 to 2 tonnes.

In a Scorpio, things like cornering grip levels, braking distance, road noise, ride quality etc are low priority variables. But the above are very important in hatchbacks and sedans.

You got to give in somewhere - and that's probably in tyre life.
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Old 2nd October 2016, 22:26   #6
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

An interesting thread but long back I learnt from my friends on how these SUV tires easily last for at least 70,000 KMS for most of the drivers.

But on the other side where you are referring to tires on Hatchbacks or regular monocoque cars lasting less than 50,000 kms, I have to say that all the tires in both my cars till now have at least seen 70,000 kms of "useful" life no matter what brand they were - JKs, Bridgestones, Michelins.

In fact only recently, I had to update a query on tires on the Ertiga and look at them after running for exactly 84,000 kms (They were replaced when odo was 16,000). They can still do at least another 5000 kms.

Tyre life: Monocoque vs ladder-on-frame cars-tires.jpg

And to tell you a fact, they have visited for alignment and balancing for not more than 3-4 times in their life till now. Not because I ignore that but I don't want to touch something when its alright.

The current set on the WagonR was replaced at 1,65,000 kms and today the ODO is 2,32,000 and they have good life left after 67,000 kms of running till now.

I believe the better life of SUV tire are mainly to do with the compound and the fact that they are designed for usage - Withstand loads, abuse due to bad roads etc that gives it more life compared to regular tires on our cars.
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Old 3rd October 2016, 00:05   #7
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

A very interesting observation.

The way I see it, tyre life is largely dependent on the sliding friction.

A small hatch has a better power to weight ratio and is more nimble, and hence moves around more quickly - add to it, the tiny tires. Where as an SUV is slow off the foot, and is less nible. Even around the corner, you dont throw the SUV (when compared to the weight) around like the little hatch.

Basically, the driving itself saves tires for the SUV. And also, the fact that the SUV's have harder rubber to withstand the abuse.

However: Good Maintenance is an important variable here. A badly maintained SUV (alignment wise) tire will wear out faster than the little one.
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Old 3rd October 2016, 08:17   #8
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Quote:
Originally Posted by paragsachania View Post

But on the other side where you are referring to tires on Hatchbacks or regular monocoque cars lasting less than 50,000 kms, I have to say that all the tires in both my cars till now have at least seen 70,000 kms of "useful" life no matter what brand they were - JKs, Bridgestones, Michelins.
That basically boils down to your very good driving manners I am yet to see a monocoque having as good a tire life, save for Yeti on Latitude Tour HP's which did close to 70,000 kms. Am clueless on what kms does the XUV tires last.

Remember the Figo I had, I was about to go for a tire change if I had kept it longer [but the guy who bought it from me, is yet to change the tires] The tires were MRF ZV2K and they had become hard and didn't provide much grip either.

On the other hand, with 28,000 kms on the Scorpio 4X4, the tires are almost as good as new.

The Scorpio isn't pushed as a normal hatch but does see lots of bad roads/off-road situations which should be determinable to tire life, no..?
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Old 3rd October 2016, 08:35   #9
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Bridgestone's S689 would have a harder compound than the Michelin Lattitude .. yet, the Michelin's @51k on my Storme are holding comparably to the OE Bridgestone's @ 97k on my Sumo.
Quote:
Originally Posted by paragsachania View Post
I have to say that all the tires in both my cars till now have at least seen 70,000 kms of "useful" life no matter what brand they were - JKs, Bridgestones, Michelins.
Parag, One factor for you is the higher % of highway drives that you do. Lesser braking means lesser tyre wear.
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Old 3rd October 2016, 10:57   #10
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Quote:
Originally Posted by condor View Post
Bridgestone's S689 would have a harder compound than the Michelin Lattitude .. yet, the Michelin's @51k on my Storme are holding comparably to the OE Bridgestone's @ 97k on my Sumo.
We have loads of threads that talk about how BS S Series live longer than Michelin counterparts mainly due to their compound. I have friends who have got as less as 30,000 kms on Yokos.

Quote:
Parag, One factor for you is the higher % of highway drives that you do. Lesser braking means lesser tyre wear.
Just one of the factors but still my daily office runs are no less than 70-80 kms that sees good stop and go traffic until recently when I shifted to NICE road for my return drives.

Factoring all the reasons like Driving style, Road pattern, Nature of vehicle, maintaining the right pressure etc, there is absolutely no doubt that SUV Tires have longer life compared to the rest for reasons mentioned by various experts, mainly the rubber that withstands abuse like Dhanush puts it.

Last edited by paragsachania : 3rd October 2016 at 11:00.
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Old 3rd October 2016, 11:25   #11
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I guess the mileage would also depend on how long it takes to use those tyres. We have been changing Michelin XMs every 30-35k kms. But considering our average usage of 7-8k kms a year, they lasted for 4-5 years and that is good enough for the money spent, despite the low mileage achieved.
So maybe the examples you have been looking at are similar to our usage scenarios.
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Old 3rd October 2016, 12:02   #12
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Default re: Tyre life: Monocoque vs ladder-on-frame cars

Tyre wear depends on a lot of factors

. Driving style - with aggressive acceleration and braking the tyres will wear out much faster

. Tyre compounds - softer compounds used for superior grip wear out faster than harder compounds

. Age - as the tyre ages it deteriorates faster. So the tyres on a car run 25K km in 5 years will exhibit similar wear to a vehicle that has done 60K km in three years.

A sedan is driven faster, has softer compounds and generally driven less than the SUV, hence it has every thing in accelerated tyre wear. Where sedans are driven with less aggression, accumulate 20K+ km/y and use harder compund tyres, the tyre life is same as a well driven SUV.
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Old 3rd October 2016, 14:12   #13
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Default Re: Tyre life: Monocoque vs ladder-on-frame cars

The driven axle may also matter. Most if not all ladder frame vehicles are rear wheel drive. Most monocoques are front wheel drives. In front wheel drive cars the the front tyres have put the engine power to tarmac. Plus when braking the front axle takes on the majority of the braking load since suspension "dips" and the front axle loads up. This is irrespective of the axle being driven. Hence in front wheel drives the front tires tend to wear out much faster. It is very important to rotate the tires religiously in a front wheel drive but many don't. May be this explains the worn treads.
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Old 3rd October 2016, 14:41   #14
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Default Re: Tyre life: Monocoque vs ladder-on-frame cars

On my Indica turbo, I changes the Bridgestone tyres at 90K kms over a period of 8 years. They would have easily lasted for another 35K kms but since numbers of years was also high I though it was better to change them. I changed them with again with Bridgestone. I usually don't drive rough, no unnecessary acceleration / stopping. The car has been driven across a variety of roads including very bad roads to excellent highways. If driven properly, I think the tyre life can increase by about 20-25 percent.
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Old 3rd October 2016, 15:28   #15
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Default Re: Tyre life: Monocoque vs ladder-on-frame cars

Quote:
Originally Posted by Slowjet View Post
On my Indica turbo, I changes the Bridgestone tyres at 90K kms over a period of 8 years.
Slowjet, running a car on tyres 8 year old.
Dear friend, tyres are the most important item on a car when it comes to safety. Your life is much more valuable and never take the risk of driving a car with shoes more than 5 years old. Even if the the mileage derived from the tyre is less, DO REPLACE once the tyre is 5 year old. Not worth taking the risk of life for few thousand rupees.
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