Which way is which? Should the tread depth count down be on the outside for all wheels?

This is one of those SAT questions that always got me. Can you all help me out. Long story short, I'm the pround owner of a new set of these NRVis. They just don't look right to me, though...

They are all going in the right direction (very helpful little arrows). However, the left side wheels have the "tread count down" on the outside portion of the tire, and the right side wheels have the "count" on the inside portion.

This just does not sound right to me. Did the shop screw up, or am I just not getting it?

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

looking at the tread pattern, the tire seems to be unidirectional, and that's why it was mounted the way you described.

this is one of those tires that is both asymmetric and unidirectional.

Thanks, man. I really appreciate your quick reply. It does make me feel better...

I understand the asymetrical thing, but I just can't "see" how it would not provide different handling characteristecs for left vs. right turns.

If you look very closely, there is a significant difference in the tread pattern for the inside and outside of each tire.

Shouldn't there be a way to be symetrical all around AND have all the tires going in the right direction?

My head hurts. Thanks in advance for any helpful input. I'm mixing another drink.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

These properties have been achieved by setting the outmost steel belt in a reverse angle towards the asymmetric featherlike pattern of the centre.

Well... I guess I'm back to the shop.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

Bobbyv - I owe you a beer. Thanks again for your help.

After further checking with the wholesaler and the good folks at Nokian USA, the tires (as described above) are mounted correctly.

It's a pretty cool tire. 195/65/15 - 95V HD $114.95 per tire from K&B Tire (Richmond, VA)

My NRH2 tires were awsome... sad to see them go. They lasted almost 60,000 miles The NRVi feels even better.

From Nokian's marketing stuff...

Nokian Tyres has developed two new summer tyres for the highest performance categories. The Nokian NRVi and Nokian NRY tyres are designed for top speeds and demanding driving, whilst at the same time reflecting the Nordic manufacturer's key motto: durable safety.

Nokian NRVi

In the development of Nokian NRVi, the key focus areas were its aquaplaning properties, wet grip and wear resistance. As a result of testing dozens of different tread patterns, an entirely new tread design, symmetric at the shoulders and asymmetric at the centre, was developed.

The tyre's rolling direction is set by the arrow-like centre pattern. According to Nokian, numerous tests on different tracks have indicated that a directional pattern (with fixed rolling direction) is the most effective in removing water from between the tyre and the road, even at high speeds.

Nokian NRVi is directionally steady and durable. These properties have been achieved by setting the outmost steel belt in a reverse angle towards the asymmetric featherlike pattern of the centre. The tyre has a precise and soft impact with the road, which improves its braking capacity and ensures an even wear pattern. The symmetric shoulders of the tread pattern emphasise excellent cornering properties.

It was also desired to improve the wet grip of the Nokian NRVi. Usually, high-speed category tyres lose some of their grip in cool temperatures. However, the Nokian NRVi's new full silica mix functions well in any summer temperature, braking tests having been carried out at both cool (some +8°C), and warm (some +25°C) environments.

The tyres were tested on Nordic, rough asphalt and smooth Central-European asphalt as well as concrete surface. Tyre noise has also been minimised with several different solutions. In addition to the optimal tread pattern block distribution and structural choices, circumferential platforms have been designed on the bottom of the main grooves together with small cavities on the pattern blocks next to the main grooves. These elements break the high-frequency noise that forms when driving on smooth road surface in straight grooves (the so-called organ pipe effect). The tyre's pass-by and cabin noise is of low level and pleasant tone.

Intended for high-performance cars, V-speed category tyres are usually installed on light-metal rims that are impressive but can wear easily. However, the bead area of the Nokian NRVi has been renewed. A sealing circle was added to the rib that protects the rim. The design protects the area between the tyre and the rim from sand, mud and impurities. There is an info field in the tyre's bead area that facilitates tyre maintenance and increases the driver's comfort. The info field contains a list of recommended inflation pressure value. The tyre mechanic marks the correct inflation pressure of the tyre in the info field with a silver pencil. When checking the inflation pressure, the driver can confirm the right pressure level from the info field. Next to the pressure record there is a chart for marking the tyre's placing under the car. This mark will help remember the tyres' places after out-of-season storage.

As with most Nokian products, the Nokian NRVi also has a wear indicator (driving safety indicator, DSI) that informs in clear figures how many millimetres of tread the tyre has left. The Nokian NRVi is a speed category V tyre (240 km/h), manufactured in 19 sizes.

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Michael

1988 300 SL (5 Speed)
1994 E320 Wagon
1997 C230

you're welcome, Michael. Frankly, that tire threw me off a bit too. Consulting the Nokian website confirmed my initial thoughts about the design.

i drive on the leftmost lane of the highway most of the time, which slopes down to the left for drainage purposes, and which imposes an asymmetric wear pattern on the tires, as the car has a tendency to steer down the slope as it goes. Maybe this is the tire for me!