[badri]

One of the XM2's of my Innova developed a sidewall puncture. It was so small that it took 2-3 days for me to notice the reduction in tyre pressure. There was no nail or any other foreign object. This is not the same tyre that had the side wall scrape mentioned in the earlier posts.

I intend to put in a tube and use this as spare.

[avira_tk]

First puncture after around 5k kms, the nail looked pretty tiny. The pressure drop was quite evident. The reason I noticed was that the tyre shop had replaced the OEM valves with some cheap make, its now impossible to inflate with a foot pump.

It looks like a nail, about 15mm long and about 1mm wide.

[EagleEye]

We had fitted XM2s in our Verna a few months back. I just wanted to ask the gurus about the line that runs around the tyre on the inside. (See pic) What is the functionality of this?

Strange thing is, this is there only on our front tyres and not on the rear ones. :O

[nitrous]

Originally Posted by EagleEye

Strange thing is, this is there only on our front tyres and not on the rear ones. :O

Attachment 1094546

Could be different variants.
What are the manufacturing week/year codes on the 4 tyres?

[zenren]

Originally Posted by Top-Gear

Having been enlightened by fellow members on the need and benefits of going in for a tyre upgrade over stock tyres, I too went for an upgrade for my brand new Amaze. The stock tyres were MRF 175/65 R14. I went in for Michelin Energy XM2 185/65 R14 and am very pleased with the results.

Any specific reason why you went for 185/65R14? 185/60R14 seems to be the correct upsize for Amaze which is available for XM2. 185/65 profile takes the circumference difference from OEM spec over 2%.

Originally Posted by EagleEye

I just wanted to ask the gurus about the line that runs around the tyre on the inside. (See pic) What is the functionality of this?

Originally Posted by nitrous

Could be different variants.
What are the manufacturing week/year codes on the 4 tyres?

40/12 XM2 in my Swift has that additional line, though I had never noticed it till now. Looks like they removed it in newer tyres, if it is missing in 2 of the tyres for EagleEye.

[Sankar]

Originally Posted by EagleEye

We had fitted XM2s in our Verna a few months back. I just wanted to ask the gurus about the line that runs around the tyre on the inside. (See pic) What is the functionality of this?

Strange thing is, this is there only on our front tyres and not on the rear ones. :O

Attachment 1094546

All 4 XM2 tires i have on my swift have this circumferential groove on the inside (iirc) edge, i bought the XM2 in Sep 2012. Maybe the new tyres doesn't have this groove? So you may have got 2 from the old batch and 2 from the new.

As for the functionality of this, i believe this is to minimise irregular shoulder wear.

[Top-Gear]

Originally Posted by zenren

Any specific reason why you went for 185/65R14? 185/60R14 seems to be the correct upsize for Amaze which is available for XM2. 185/65 profile takes the circumference difference from OEM spec over 2%.

The OEM tyre size was 175/65 R14 so I only increased the width by 1 cm. Maybe I am missing something here, but how would that increase the circumference?

[vikram_d]

Originally Posted by Top-Gear

The OEM tyre size was 175/65 R14 so I only increased the width by 1 cm. Maybe I am missing something here, but how would that increase the circumference?

To understand how the circumference will increase you need to understand how tyre sizes are marked. For eg. let's take 175/65 R14. In this size 175 is the width of the tyre and 65 is the aspect ratio. That means the sidewall height is 65% of 175. R14 is the internal diameter of the tyre and that is 14 inches.

So taking this into consideration let's calculate sidewall height.

175 * 0.65 = 113.75mm

For a 185/65 R14 tyre the sidewall height will be

185 * 0.65 = 120.25mm

R14 denotes the internal diameter of the tyre and not the external.

Converting R14 into millimeters we get

14 * 25.4 = 355.6mm

To this add sidewall height multiplied by 2

For 175 tyre
355.6 + (113.75 * 2 ) = 583.1mm (external diameter)

For 185 tyre
355.6 + (120.25 *2) = 596.1mm (external diameter)

This had given you the outside diameter of the tyre and with this you can calculate the circumference

Circumference = 3.143 * external diameter

For 175 tyre = 3.143 * 583.1 = 1832.7mm
For 185 tyre = 3.143 * 596.1 = 1873.5mm

So you can see that just a 1cm increase in width has resulted in an increase of almost 41mm in the circumference of the tyre.

[Top-Gear]

Originally Posted by vikram_d

To understand how the circumference will increase you need to understand how tyre sizes are marked.

So you can see that just a 1cm increase in width has resulted in an increase of almost 41mm in the circumference of the tyre.

Thanks a lot for the detailed explanation! I missed the fact that the sidewall height would also go up proportionally .

Do you think I could have issues with 185/65 R 14 instead of the stock 175/65 R14?

[vikram_d]

Originally Posted by Top-Gear

Thanks a lot for the detailed explanation! I missed the fact that the sidewall height would also go up proportionally .

Do you think I could have issues with 185/65 R 14 instead of the stock 175/65 R14?

No you will not have any issues as the speed variance is 2.23% too fast. That means when your car's speedometer is showing 100kmph, you will actually be travelling at 102.23kmph. But keeping in mind that all stock speedometers have some amount of error you should not face any problems. So just enjoy the new tyres and don't worry about anything.

That being said it is generally recommended to have the variance below 2% in either direction.

[kumards]

A couple of weeks back, I changed my Baleno VXi tyres (2006, 50k, Goodyear Eagle NCT5s, 185/65 R14) to Michelin XM2s (185/70 R14). The hope is that the larger tyres will improve the ground clearance, even if marginally.

I changed only the main tyres, and kept one of the old tyres (best of the 5) as the spare, but now realize that the spare is of a smaller size! Should I get a new spare too of the larger size? Or, can I use the odd-size spare for a short distance till the puncture shop?

Fyi: I bought the tyres from Tyre Empire, HSR (Bangalore). The total cost -- 4 tyres, balancing, alignment, weights, new valves, minus Rs.400 for the old tyres came to Rs.18900.

[deetjohn]

Originally Posted by EagleEye

Strange thing is, this is there only on our front tyres and not on the rear ones.

Were you able to check the manufacturing date on the tyres?

[EagleEye]

Originally Posted by deetjohn

Were you able to check the manufacturing date on the tyres?

The car is in Chennai, I've asked my brother to check and tell me. Since he was out of town, he'll tell me by today/tomorrow.

[avisidhu]

Folks, planning to upgrade the stock tyres on my ANHC to XM2.

195 is what I am hoping to get, does anyone have any prior experience on the same for the ANHC? Or do you think 185 will suffice?

Also, Will the existing spare tyre serve its purpose in case of an emergency? I do not intend to change it since its been rarely used.
Many thanks

[bigben]

last June I changed the shoes of my Vista. Decided to go in for XM 2 as they were new at that time and promised a very advanced tyre.
I have not been disapointed. the Tyres offer good grip, are silent and look great as well.

The problem I have with these tyres are what you will notice in the pic. Rubber pieces have come off the tyre. while this is only one tyre there are others that have the similar issue but are smaller in size. I mostly drive on the service roads of the ORR which is extremely smooth. Apart from stones occasionally strewn on the road.

I did reach out to the michelin sales team and they checked the tyre and said it was normal.

So now I have decided to ask everybody here about this.
1) The others who have these tyres on their car. Have you noticed this happen to your tyres?
2) Why is this happening? Is it normal?
30 what needs to be done to prevent it from happening?