Tyre Sidewall Markings

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caprihorse
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In addition to the tyre's brand and line names (tyre model), there is a lot of information provided by the manufacturer on the sidewalls of the tyres they produce.

Here I’m describing the most essential markings to understand their meaning. It is very important to understand what you have on your car, to have the most optimal driving experience. Sometimes in addition to manufacturer’s recommendation, the right size of the tyres for your car can make a magic.

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275/70R16 114T

275 – Nominal width in mm, the widest point from both outer edges
70 – Ratio of the sidewall height to the total width of the tyre, as a percentage
R – radial, D – diagonal
16 – Diameter in inches of the wheel that the tyres are designed to fit
114 – Payload is a numerical code stipulating the maximum load (mass, or weight) each tyre can carry.

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T – Speed rating

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M + S – Mud and snow

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3509 – The week and year tyre was manufactured (week 35, 2009). This is very important information, as older tyres tend to pop out of the rim, much more easily as newer tyres.

Red and yellow dot - The red dot that you find on the tyre is a alignment mark for the tyre valve, the yellow dot is the heavy spot of the tyre, to indicate to the technician, if he has an out of balance wheel assembly to counter balance of the wheel and tyre assembly

Typical terrain tyres

H/T – Highway Terrain tyres. These tyres are recommended for drivers who spend limited time off-road. The tyres have a shallower tread depth, which allows lower noise levels because there is less air passing through the tread grooves. The tyres have thinner side walls when compared to other terrain types and this greatly improves ride comfort because the tyre casing is more flexible. The use of thinner belt wire also gives a smoother ride because the tread area conforms to the road surface much more easily.

A/T – All Terrain tyres. These tyres offer good versatility by offering capability on a wide variety of surface types, from dry sealed roads to dirt tracks and fair mud play. Considerable advances in technologies mean these tyres can now be used for everyday driving on the road, with acceptable level of grip and ride comfort. Better tyre designs have improved traction, greater gravel wear resistance and decreased stone retention. Bruise and puncture resistance is supported by multiple full-width steel belts, whilst giving precise steering response and cornering control. Many manufacturers are also using harder tread compounds which provide maximum longevity. The weight is higher then H/T tyres.

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Mukhallalati Basha
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I've been always reading such information but never realized what they could mean.

Thanks a lot for this useful article.
Duck Commander
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wow nice and very comprehensive info about tires which is always my favorite subject.
Thanks alot for sharing the knowledge.
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caprihorse
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shafiq jan;2014 wrote:wow nice and very comprehensive info about tires which is always my favorite subject.
Thanks alot for sharing the knowledge.
Did you check your tyres? What's the age? Do you remember our last trip? :060:
Duck Commander
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hehehe Capri...... my these tires are very fresh I mean 2010, and still you can smell the fresh smell like fresh marlbolo lights hehehehe.
Desert Ranger
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hi guys,

Its time to change the rubber. but i am not sure which tires type will do good in sand. A wide tire, or a narrow tire.? however I went through number of articles on google and found few points. As per my experience i dont personally know whether narrow is better than wider off-road tires. so i need your advice. however i will paste here few of the points which suggest narrow are better than wider tires off-road. how true is it as per you?

"- A narrow tire presents less rolling resistance on improved surfaces, increasing fuel economy and performance.
- Narrow tire presents less surface area to the medium which will cut easier through sand than a wide one (due to resistance) especially when turning in sand. When the front tires turn, they present a wider surface to the sand.
- N
arrower, lighter wheel, the effect on rotating mass is significant as a lighter tire is easier to accelerate and stop.
-
It is a common misconception that airing down a tire for off-road traction only makes the tire contact patch wider. That is not the case. In fact, only 20% of the increased contact comes from the width. 80% of the increased contact patch comes from the tread patch becoming longer. A tall, narrow tire allows for a very long contact patch when aired down. That, coupled with the minimal frontal resistance (area), negates much of the downside to narrow tires in flotation situations. The taller tire allows for a long contact patch and still maintains good ground clearance.

As quoted from Sahara Overland, a Route and Planning Guide by Chris Scott (2004, ISBN: 1-873756-76-3):
"...Note that it's the diameter or height of the tyres that makes the difference in sand, and not, as many imagine the width... For the desert, you want tyres with a high aspect ratio of around 80 because this represents a taller sidewall so corresponds to added ground clearance when firm, and a longer contact area when deflated"


Please comment. :)
Gorgin4325
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Find my response in red.
Desert Ranger;14426 wrote:hi guys,

Its time to change the rubber. but i am not sure which tires type will do good in sand. A wide tire, or a narrow tire.? however I went through number of articles on google and found few points. As per my experience i dont personally know whether narrow is better than wider off-road tires. so i need your advice. however i will paste here few of the points which suggest narrow are better than wider tires off-road. how true is it as per you?

"- A narrow tire presents less rolling resistance on improved surfaces, increasing fuel economy and performance.

True, but not ideal for the desert. I highly doubt that real offroaders think about fuel economy :)


- Narrow tire presents less surface area to the medium which will cut easier through sand than a wide one (due to resistance) especially when turning in sand. When the front tires turn, they present a wider surface to the sand.

The theory is true. However, you don't want to "cut through" sand in the desert. You want to driver over it. So I say the wider the better. But it is a compromise since most of us drive our cars both on-road and off-road.


- Narrower, lighter wheel, the effect on rotating mass is significant as a lighter tire is easier to accelerate and stop.

True. But once again, you want the most surface area with sand that you can get without going with heavy wheels and tires. That is one of the reasons we deflate. To make the tires wider and softer without adding weight.


-
It is a common misconception that airing down a tire for off-road traction only makes the tire contact patch wider. That is not the case. In fact, only 20% of the increased contact comes from the width. 80% of the increased contact patch comes from the tread patch becoming longer. A tall, narrow tire allows for a very long contact patch when aired down. That, coupled with the minimal frontal resistance (area), negates much of the downside to narrow tires in flotation situations. The taller tire allows for a long contact patch and still maintains good ground clearance.

The concept makes sense and I partialy agree with it. However, what am I suppose to do if I cannot fit a 40 inch tires on my car? I air down to get the tire as wide as physically possible without the tire jumping off the rim at every turn.

Also, by adding a larger tire, you will increase the rotating mass of the wheels. To me that is not ideal unless you REALLY need it. Have a look at rock crawlers' rigs.


As quoted from Sahara Overland, a Route and Planning Guide by Chris Scott (2004, ISBN: 1-873756-76-3):

"...Note that it's the diameter or height of the tyres that makes the difference in sand, and not, as many imagine the width... For the desert, you want tyres with a high aspect ratio of around 80 because this represents a taller sidewall so corresponds to added ground clearance when firm, and a longer contact area when deflated"

Let's not forget that when we (Middle East Residents) refer to sand, we mean mostly desert driving, similar to what you experience with Almost4x4. In most other countries driving on the beach is considered driving in sand, which is true, but totally different from our terrain. Therefore, what works on the beach might be completely different from what works in Al Badayer!


Please comment. :) ​I just did :) hehe

Based on all of the above, tell us what tires you are currently running, and I'm sure we can recommend the correct combination for your car.

Thanks
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caprihorse
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Desert Ranger;14426 wrote:hi guys,

Its time to change the rubber. but i am not sure which tires type will do good in sand. A wide tire, or a narrow tire.? however I went through number of articles on google and found few points. As per my experience i dont personally know whether narrow is better than wider off-road tires. so i need your advice. however i will paste here few of the points which suggest narrow are better than wider tires off-road. how true is it as per you?

"- A narrow tire presents less rolling resistance on improved surfaces, increasing fuel economy and performance.
- Narrow tire presents less surface area to the medium which will cut easier through sand than a wide one (due to resistance) especially when turning in sand. When the front tires turn, they present a wider surface to the sand.
- N
arrower, lighter wheel, the effect on rotating mass is significant as a lighter tire is easier to accelerate and stop.
-
It is a common misconception that airing down a tire for off-road traction only makes the tire contact patch wider. That is not the case. In fact, only 20% of the increased contact comes from the width. 80% of the increased contact patch comes from the tread patch becoming longer. A tall, narrow tire allows for a very long contact patch when aired down. That, coupled with the minimal frontal resistance (area), negates much of the downside to narrow tires in flotation situations. The taller tire allows for a long contact patch and still maintains good ground clearance.

As quoted from Sahara Overland, a Route and Planning Guide by Chris Scott (2004, ISBN: 1-873756-76-3):
"...Note that it's the diameter or height of the tyres that makes the difference in sand, and not, as many imagine the width... For the desert, you want tyres with a high aspect ratio of around 80 because this represents a taller sidewall so corresponds to added ground clearance when firm, and a longer contact area when deflated"


Please comment. :)
All these arguments remind me on bicycle wheel and its tyre (20 x 1.5 typical), which is huge in diameter and narrow enough to be within above mentioned theory. Now imagine, how you would confirm this theory in practice?
Let's say following:
  1. Start at Al Badayer, deflating your bicycle tyres by 20% (1 psi?)
  2. Drive into sand after shops
  3. What distance you can make in sand? (2 metres?)
  4. What about your HP and torque?
  5. And air intake?
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yasir
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Desert Ranger;14426 wrote:hi guys,

Its time to change the rubber. but i am not sure which tires type will do good in sand. A wide tire, or a narrow tire.? however I went through number of articles on google and found few points. As per my experience i dont personally know whether narrow is better than wider off-road tires. so i need your advice. however i will paste here few of the points which suggest narrow are better than wider tires off-road. how true is it as per you?

"- A narrow tire presents less rolling resistance on improved surfaces, increasing fuel economy and performance.
- Narrow tire presents less surface area to the medium which will cut easier through sand than a wide one (due to resistance) especially when turning in sand. When the front tires turn, they present a wider surface to the sand.
- N
arrower, lighter wheel, the effect on rotating mass is significant as a lighter tire is easier to accelerate and stop.
-
It is a common misconception that airing down a tire for off-road traction only makes the tire contact patch wider. That is not the case. In fact, only 20% of the increased contact comes from the width. 80% of the increased contact patch comes from the tread patch becoming longer. A tall, narrow tire allows for a very long contact patch when aired down. That, coupled with the minimal frontal resistance (area), negates much of the downside to narrow tires in flotation situations. The taller tire allows for a long contact patch and still maintains good ground clearance.

As quoted from Sahara Overland, a Route and Planning Guide by Chris Scott (2004, ISBN: 1-873756-76-3):
"...Note that it's the diameter or height of the tyres that makes the difference in sand, and not, as many imagine the width... For the desert, you want tyres with a high aspect ratio of around 80 because this represents a taller sidewall so corresponds to added ground clearance when firm, and a longer contact area when deflated"


Please comment. :)
Please find below a useful articles on role of pressure in sand driving:
http://4wheeldrive.about.com/gi/dynamic ... fjun96.htm
Desert Lizard
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The referenced web site provides proof that the higher aspect ratio makes perfect sense, and it is the major contributor to larger surface area. However, like any theory, the application needs to be done with practicality in mind. Consider the following, in random order:

How high is your vehichle.. The bigger diameter tyre needs more space to prevent the tyre from hitting the body when you go into a ditch.
Along the same line, the space available in the wheel well (where the tyre fits) should be enough for the tyre lateral movement, ie when cornering. You don't want the tyre to rub into the fender walls. You may notice that all the big tyres are on LIFTED vehicles..

Considering the above, there isn't much you can do about the tyre diameter. Unless you lift the car, and increase the size of the wheel well, your pretty much stuck with a similar tyre diameter as to the one the manufacturer put on your vehicle. So, for practicality, the diameter argument holds little relevance here. If the diameter is the same, then the deflated wider tyre will give more surface are.

The aspect ratio (defined as tyre sidewall height divided by tyre width) is different though and may require changing to smaller rims assuming that the tyre diameter has to remain what it is. However, you might just get away with a slight increase in diameter to increase aspect ratio without changing rims.

The tyre construction also plays a role. Some tyres can be deflated more than others, and therefore give you more surface area for the same diameter and aspect ratio, without increasing the chance of pop-out.

The tyre weight also plays an important role. The heavier the tyre, the more force the engine needs to move it, and therefore the weaker the car feels, and more petrol spent.

In short, bigger tires require modification (lifting, cutting blah blah), wider tires may need wider rims only but may or may not affect maneuverability.

All in all, if your car is a daily ride, then I believe your better off putting quality road tires that would handle the occasional off-road use. Then focus on developing your skills.
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