[vikram31]

Hi fellow Team-BHPians,

As an avid follower, I am writing on this forum to seek advice on what has been a scary morning for me.

The Car:
SX4 VDi (March 2011)
Driven: Approx 55k kms
Tyres:
Front: 5k driven Apollo Aceleres
Rear: Original OEM Apollo Aceleres (Driven 55k ks)

During my ownership I have constantly rotated tyres every 10k kms until earlier this year when my car was just shy of 50k and one of my front tyres got a cut on the road. I replaced this with a new tyre (Same make) and added the spare tyre (Literally unused) to replace my front wheel setup.

The Problem: One of the joys of my job is that it begins at 7 am and ends at 5. So even in a city like Mumbai, my drive from Vashi to Lower Parel is a joy in the early morning hours. Until now my car has been an absolute powerhorse and a joy in terms of ride quality, balance and stability. However, today when I was on the Vashi bridge (dry road. Perfect tyre pressure, no uneven tread), a two wheeler swerved lanes and I had to slam on the brakes hard. To my horror, my car screeched and turned exactly 90 degrees and came to a halt. The engine was still running and I could smell burnt rubber. I was driving straight and there was no turn whatsover. My steering was perfectly straight as well.

Luckily I was fully buckled in and had my hands hard on the steering. Exceptionally lucky was that the bridge was empty at that time. My approximate speed at the time could be in the 80-90 kmph area at that time.

I am freaked out by this and shudder to think what could have happened if my family was with me or if there was traffic on that road.

Looking for advice on what could have gone wrong. Should I replace the rear tyres? I am happy to replace the entire set as nothing is more valuable than life.

If so, please advise tyres with decent balance and grip (aka skid resistant) whilst also maintaining good fuel economy.

Looking forward to your advice!

Thanks

[pjbiju]

IMO, the worn out tyres at the rear had a much lower braking efficiency compared to the newer front tyres. And the difference in the braking between the front and rear must have caused the drift. Also while moving forward, when you hit the brakes, the major part of the car's weight will get transmitted to the front and this will make the rear even lighter and the tyres will have even lesser grip on the road. It is always advisable to have all the four tyres with similar tread depth & tread pattern (for a similar contact area). And I feel if you are only changing two tyres, the newer ones should go as the rear tyres which will offer better grip and reduce the chances of drifting sideways. I guess, vehicles equipped with ABS will compensate for this and you will not drift. But your braking distance will be longer. It will also be helpful to know and understand the cause of the drift better, if you can measure the tread depth of the front tyres and that of the rear tyres and share it here. What was your approximate speed at the time of braking hard?

I think you simply need to replace the rear tyres only, if the front ones are good (and they should be since they have only been used for 5k)

Originally Posted by vikram31

...

If so, please advise tyres with decent balance and grip (aka skid resistant) whilst also maintaining good fuel economy.
...

I think MRF (Z.L.O tyres), Michelin, Yokohama have all good grippy tyres (with lesser life since they are supposedly made of softer compound that offers better grip). There are tyre experts here who can guide you on this. I personally use MRF Z.L.O tyres on my Swift. They replaced the original JK tyres. I find them quite grippy. However I never have had to apply sudden brakes so far during the past 7+ years of driving the Swift. So I am not sure how they will behave under sudden braking. Anyway drifting can be the end result of a combination of tyre condition, road surface condition (sand, water, gravel etc.), weight distribution in the car, tyre pressure etc. We should take care of the tyres, tyre pressure and weight distribution in the car.

[vikram31]

Thanks pjbiju, I am confused whether I should change all 4 or just 2. Plus I dont want Acelere's any more so considering the Yokohama S Drives or Michelin Primacy LC. Could 2 of these go with my Acelere's in the front or should I take a small hit and go for a brand new set of shoes ?

[Altocumulus]

Yes, you were lucky.

Change the tyres. The tread depth are there for a reason. Since you mentioned that your regular drive involves speed, its imperative you get the rear ones changed.

Secondly, its not always the grip, tyres driven that long may fail anytime and burst. You never know. We may keep our cars spic and span however hardly anyone of us bothers to look at the tyres unless there is a puncture or visible cracks. Else we change them based on the 50k kms or time. That is a long time actually.

As far as your incident goes, it maybe possible that there was oil on the road, because of which the car skidded. Otherwise since your front have a lot of grip compared to your rear, the rears skidded and the sheer momentum turned the car.

Bottomline get the tyres changed to Michelins or something like that.

Originally Posted by pjbiju

And I feel if you are only changing two tyres, the newer ones should go as the rear tyres which will offer better grip and reduce the chances of drifting sideways.

For effective braking its always the front tyres which contributes the most. The rear ones are to reduce the momentum and help the front brakes. That's the reason why most cars have discs in the front and drums in the rear. Similar for bikes. Else it would have been the other way around.

[brraj]

Go for 10mm wider size than your stock tyres.

Hankook Ventus V12 evo.
Michelin tyres.

For peace of mind change your car which has ABS+EBD or even better if it had ESP.

I have told n number of times to my relatives, friends to go for safety features like ABS,EBD,ESP and which has Airbags. One and only answer i get in return is "I am not a racer like you".

[vikram31]

Originally Posted by pjbiju

IMO, the worn out tyres at the rear had a much lower braking efficiency compared to the newer front tyres. And the difference in the braking between the front and rear must have caused the drift..

Hi, to answer your last 2 questions..i braked around 80-90 kmph..and the diff in tread is..,.Front tread depth around 0.8 cm. Rear tread depth around 0.2 cm. So I should consider the rear tyre replacement only?

Mod Note: Please quote ONLY the relevant bits of a post. Quoting a full, long post inconveniences our mobile readers.

[bblost]

Originally Posted by pjbiju

I guess, vehicles equipped with ABS will compensate for this and you will not drift.

If I understand them correctly.
EBD helps stabilize the front and rear bias during heavy braking.

ABS helps in the left and right bias.

[vikram31]

Hey brraj. Not sure if I can replace my car yet but I have heard that MAruti offers ABS as an addon. Will check how much it costs and update you here

Originally Posted by brraj

Go for 10mm wider size than your stock tyres.

Hankook Ventus V12 evo.
Michelin tyres.

For peace of mind change your car which has ABS+EBD or even better if it had ESP.

I have told n number of times to my relatives, friends to go for safety features like ABS,EBD,ESP and which has Airbags. One and only answer i get in return is "I am not a racer like you".

Hi brraj, I am happy to loog at 10 mm increase if that improves comfort and stability. Any idea in %age terms how that impacts mileage ?

[SDP]

Vikram, don't want to alarm you, but the SX4 is a tall car with GC on the higher side. Its not really known as a stable, well-handling car. So if you ask me, don't take any chances on grip-levels. The rear-tyres should have been replaced may be 20kms back.

A personally know a guy whose SX4 toppled and flipped 3-4 times before landing upside down. He was not as lucky as you and there were multiple casualities in the accident. What surprised me was that he mentioned he has no clue what happened. He was at a decent speed, but no swerveing or braking was involved. The guy has huge amount of driving experience and the SX4 was already in its 4th year with him. Don't want to generalize based on one experience, but do consider these one-off cases and draw your own conclusions.

[vikram31]

Originally Posted by SDP

Vikram, don't want to alarm you, but the SX4 is a tall car with GC on the higher side.
=======
Don't want to generalize based on one experience, but do consider these one-off cases and draw your own conclusions.

Thanks SDP. not Alarmed but will definitely take the steps to get my car safer. ABS addon plus grippy tyres is a first step.

[rohan_iitr]

New tyres should be installed in the rear.

Please go through this thread, it will clear your doubts.

http://www.team-bhp.com/forum/tyre-a...ront-rear.html

Rohan

[Samurai]

Originally Posted by vikram31

Hi, to answer your last 2 questions..i braked around 80-90 kmph..and the diff in tread is..,.Front tread depth around 0.8 cm. Rear tread depth around 0.2 cm. So I should consider the rear tyre replacement only ?

If you are a spirited driver, you should replace at 3mm tread depth. That is safe limit for wet roads, which we often have in this season.

Originally Posted by http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=51

If rain and wet roads are a concern, you should consider replacing your tires when they reach approximately 4/32" of remaining tread depth.

[pjbiju]

Originally Posted by Altocumulus

For effective braking its always the front tyres which contributes the most. The rear ones are to reduce the momentum and help the front brakes. That's the reason why most cars have discs in the front and drums in the rear. Similar for bikes. Else it would have been the other way around.

That is true and that I believe is because, most of the weight gets transferred to the front and the front tyres have to have better braking power to take on the additional weight. But drifting happens because the rear tyres lose grip.

[vikram31]

Originally Posted by Samurai

If you are a spirited driver, you should replace at 3mm tread depth. That is safe limit for wet roads, which we often have in this season.

Noted Samurai, I guess thats a given now given the unanimous agreement that this is already overdue irrespective of the incident. Will get on it immediately.

[tharian]

Originally Posted by vikram31

Hi fellow Team-BHPians,

As an avid follower, I am writing on this forum to seek advice on what has been a scary morning for me.


Looking forward to your advice!

Thanks

You were lucky in many ways. That there were no vehicles on either side of you or in front and most lucky that the tires did not grip enough when sliding side ways and topple.
Tires are the main reason , however there can be a other reasons.
I had the same incident occur to me couple of years back and I had a smile on my face as to how it ended.

I have a Figo which is known more for its stability and handling on turns and straights. I took this a to heart and used to take turns without slowing down as this was the place I could overtake everyone easily since they slowed down.
On one such occasion, I was coming down the ramp which is almost a 90 degree curve and is also sloping down. It is 3 lane wide and there was a old Verna in the middle lane and I was in the process of overtaking him on the right lane around 60-70kmh. In the middle of the lane, I thought the Verna might loose it since his speed was more than mine and I lifted off which was the mistake.
I was on the outer edge and my right side tires were on the fine sand accumulated at the edge of the road. I lifted off, the rear right lost traction and at the same time hit the expansion joint hump on the road and before I knew it, I was sliding sideways with tires screeching and white smoke all around. It felt so unreal since that was my first experience in a car drifting and felt good, except that I knew it was a big escape.
Just like you, I was lucky there were no vehicles around. Imagine if there was a truck on the side and you rammed into him, or a two wheeler.

Maybe, if your car was loaded with 4, it may not have drifted . My tires were new and run less than 10k then, so there are many factors.
But yes in your case, you do need to change your rear tires.
Drive Safe

Regards