Understanding Tyre Specifications

[NICAT]

Hi Friends,
I want to find optimal tyre for my w163 ML, Ride quality is the only think that matters to me,
Factory tyre size for 16 inch rims is 255/65/r16
According to my research There are LT (Light Truck) and P (Passenger) tyres, where the latter is optimized for comfort.
But in my country, i cant find any tyres that neigther LT nor P is written on them. However i see A/T and H/T, M+S. Of course H/T should be more comfortable than A/T. But is H/T equivalent of P tyres ? or may H/T have LT tyres too ?
Some Typres even have H/P on them.
For example : Bridgestone Dueler H/P 109h 255/65 R16
Is this LT or P tyre ?
IF P is not written on the Tyre , is there any other way for me to clarify if it is good for comfort or not
Regards.

 

[slacktide_bitog]

Truck/commercial tires in Europe (and possibly elsewhere) will have the letter C after the tire size. For example, 255/65R16C

Your W163 probably didn't come with truck tires or commercial tires.

The H/P is just part of the name of that tire and doesn't mean anything in regards to load/LT/P or anything.
Bridgestone Dueler H/P

 

[UG_Passat]

Hi Friends,
I want to find optimal tyre for my w163 ML, Ride quality is the only think that matters to me,
Factory tyre size for 16 inch rims is 255/65/r16
According to my research There are LT (Light Truck) and P (Passenger) tyres, where the latter is optimized for comfort.
But in my country, i cant find any tyres that neigther LT nor P is written on them. However i see A/T and H/T, M+S. Of course H/T should be more comfortable than A/T. But is H/T equivalent of P tyres ? or may H/T have LT tyres too ?
Some Typres even have H/P on them.
For example : Bridgestone Dueler H/P 109h 255/65 R16
Is this LT or P tyre ?
IF P is not written on the Tyre , is there any other way for me to clarify if it is good for comfort or not
Regards.

A/T = All-terrain
H/T = Highway Tire

which are basically types of off-road tires, as they tend to be categorized by their tread pattern characteristics.

H/P = a "High performance" which tends to be a marketing gimmick

255/65 r16 tends to be more of a P-metric tire.

LT is usually reserved for truck sized tires, not really a luxury SUV from Germany.

 

[NICAT]

Truck/commercial tires in Europe (and possibly elsewhere) will have the letter C after the tire size. For example, 255/65R16C

Your W163 probably didn't come with truck tires or commercial tires.

The H/P is just part of the name of that tire and doesn't mean anything in regards to load/LT/P or anything.
Bridgestone Dueler H/P

Thanks for clarification.
Can you please tell, if P or LT is not mentioned on the tyre, is it likely to be P or LT ?
For example the tyre i mentioned above (Bridgestone Dueler H/P 109h 255/65 R16) is LT or P ? How can i know that ?

A/T = All-terrain
H/T = Highway Tire

which are basically types of off-road tires, as they tend to be categorized by their tread pattern characteristics.

H/P = a "High performance" which tends to be a marketing gimmick

255/65 r16 tends to be more of a P-metric tire.

LT is usually reserved for truck sized tires, not really a luxury SUV from Germany.

Thanks. So Can we say Any H/T at 255/65/r16 is likely P ?
And Can A/T tyres be P too at that size?
A little confusing

 

[Boomer]

Your tires are no doubt P tires. Stands for "Passenger" and are the standard type of tire for passenger cars, and even some light pick up trucks. LT are for heavier vehicles and would not be suitable for your car. So 255/65/r16 is a P tire. Just look through what is available and suits your budget and performance requirements.

 

[NICAT]

Your tires are no doubt P tires. Stands for "Passenger" and are the standard type of tire for passenger cars, and even some light pick up trucks. LT are for heavier vehicles and would not be suitable for your car. So 255/65/r16 is a P tire. Just look through what is available and suits your budget and performance requirements.

Thanks This was good to know

 

[930.engineering]

For example : Bridgestone Dueler H/P 109h 255/65 R16

It's certainly 255/65 R16 109H, while '109' is the load rating.
This size is also available with a 113 load rating which I'd avoid
as it'd likely affect ride comfort and that's one of your goals.
Despite aforementioned categories some offerings are more
road focused* and probably more silent running, while others
also exhibit some off-road performance**. I'd suggest these:

Goodyear Wrangler HP All Weather*
Continental ContiCrossContact LX 2**
Bridgestone Turanza T005*
Bridgestone Dueler H/P Sport**
.

 

[slacktide_bitog]

Thanks for clarification.
Can you please tell, if P or LT is not mentioned on the tyre, is it likely to be P or LT ?
For example the tyre i mentioned above (Bridgestone Dueler H/P 109h 255/65 R16) is LT or P ? How can i know that ?



Thanks. So Can we say Any H/T at 255/65/r16 is likely P ?
And Can A/T tyres be P too at that size?
A little confusing

They're P

and yes, AT tires can be P

 

[NICAT]

It's certainly 255/65 R16 109H, while '109' is the load rating.
This size is also available with a 113 load rating which I'd avoid
as it'd likely affect ride comfort and that's one of your goals.
Depite aforementioned categories some offerings are more
road focused* and probably more silent running, while others
also exhibit some off-road performance**. I'd suggest these:

Goodyear Wrangler HP All Weather*
Continental ContiCrossContact LX 2**
Bridgestone Turanza T005*
Bridgestone Dueler H/P Sport**
.

Oh, thanks for mentioning load rating, i didnt even know that.
So the more load rating, the worse ride quality right ?
And are those load ratings standart across all tyre types ? i mean any sized tyre that has 112S, means they are capable of enduring similar load ?

 

[930.engineering]

.
Yes and yes. Increased load rating index equals to more plies,
which makes a tire heavier and stiffer. It's a global standard, so
it's the same for all tires. The LI of 109 is common for that size.
However the resulting ride comfort will vary from manufacturer
to manufacturer.
My former father in law owned a W163 ML320 back in late 90s
when the M-class first hit the market. I remember ride comfort
hasn't been as excellent as a C-class or an E-class of that time,
and that's most certainly due to using much higher mass axles.
Same with the R-class a friend had (which I think is the ugliest
MB of all time).
There's no way to get around that, so it's best to keep the stock
tire size and load rating, get the most comfortable tire (I made
good experiences with GoodYear in this regard, so I'd pick the
Wrangler HP All Weather) and to not increase the tire pressure.
.

 

[CapriRacer]

There is nothing in the tire specs that is going to tell you about the ride quality. That's because the ride quality is controlled by the size of the filler and that can not be found on the sidewall.

What you need is a comparison of ride quality for tires that yo are considering. That might be hard to come by.

 

[930.engineering]

Not too hard, as you'll perhaps find some appropriate tire
reviews and you'll likely find GY Wrangler HP All Weather
to come off well in them.
That said, I don't agree. Load index definitely affects ride.

 

[NICAT]

There is nothing in the tire specs that is going to tell you about the ride quality. That's because the ride quality is controlled by the size of the filler and that can not be found on the sidewall.

What you need is a comparison of ride quality for tires that yo are considering. That might be hard to come by.

Yes sir, you are right that different tire models may have different ride quality, even if their specs are same,
But what i meant was which spec is more likely to affect ride quality on general basis.
As far as i understand, the tire, in order to endure high load, needs to be strong and stiff, otherwise under high pressure, it may blow, or deform badly even if it does not blow.
Or to be clear, is it possible to make a tire that will be comfortable (means will easily deform to absorb the bumps) but not deform when it is under high pressure ?
Again this is my understanding which can be very wrong

 

[CapriRacer]

..........
That said, I don't agree. Load index definitely affects ride.

Ah ....... Mmmmm ....... Not exactly.

If you meant the difference between Standard Load (SL) and Extra Load (XL), or the difference between Load Range C, D and E, or the difference between 6 Ply Rating and 8 PR (or 10 PR), then I agree. Unfortunately, there isn't a term for those. In Europe, they use Load Index as a differentiator, but saying it that way leads to a wrong conclusion.

Ya' see, P type tires come in 3 varieties: Tires based on the US standard (P metric), which have a "P" in front of the numbers, Tires based on the European standard (ETRTO), and tires based on the Japanese Standard (JATMA) do not. There are other standards, but they generally follow one of those 3.

In this case, a 255/65R16 SL P metric tire has a load index of 106. An EU tire has a LI of 109, and a tire built to the Japanese standard also has a LI of 109.

But, wait, you say, doesn't that mean the tires are different construction? No, because if you look more closely, the P metric tire is rated at 35 psi (241 kPa, 2.41 bar), while the Japanese and Europeans use a rating pressure of 250 kPa (2.5 bar, 36.3 psi) and that additional pressure results in a higher load rating. If you do the math, and get all 3 types of tires to the same rating pressure, you'll find the load carrying capacity of the tires is very close - so no difference in construction is required. Different manufacturers might use slightly different constructions, but that difference is NOT caused by the Load Index difference.

What that means is there is nothing in the tire designation that will lead you to know if the ride quality is better or not, IF all the "specs" are the same - that is, size, and SL or XL.

And it is important to word things very carefully. The difference between an SL and an XL does result in a different LI, but LI by itself is NOT an indicator of ride quality.

And just for reference, Tire Rack says there aren't XL's or LT's in a 255/65R16 size, only SL's, but there are P metrics!

 

[CapriRacer]

Yes sir, you are right that different tire models may have different ride quality, even if their specs are same,
But what i meant was which spec is more likely to affect ride quality on general basis.
As far as i understand, the tire, in order to endure high load, needs to be strong and stiff, otherwise under high pressure, it may blow, or deform badly even if it does not blow.
Or to be clear, is it possible to make a tire that will be comfortable (means will easily deform to absorb the bumps) but not deform when it is under high pressure ?
Again this is my understanding which can be very wrong

So trying to address your questions directly, even speed rating isn't a good indicator of ride quality - contrary to what many people think. Ya' see, the tire size you indicated tells a lot about what vehicle it is going on, so constructions tend to be similar. Ride quality - at the same pressures - is largely controlled by that filler, and there is nothing in any of the specs that is going to tell you about that - not max pressure, not Load Index.

So you are going to have to rely on someone doing back to back ride tests and publishing their results.

 

[NICAT]

So trying to address your questions directly, even speed rating isn't a good indicator of ride quality - contrary to what many people think. Ya' see, the tire size you indicated tells a lot about what vehicle it is going on, so constructions tend to be similar. Ride quality - at the same pressures - is largely controlled by that filler, and there is nothing in any of the specs that is going to tell you about that - not max pressure, not Load Index.

So you are going to have to rely on someone doing back to back ride tests and publishing their results.

Thanks Again nice explanation,
While i replaced my A/T with H/T tyres, i had chance to stand on those tyres on the ground, they were not installed on the rims, A/T tyres were able stay without almost any deformation , keeping my weight 70KG, while H/T tyres flexed down immediately.
Do you think, if there are several tyres at the shop, trying to flex sidewall or other parts of tyre with hand may give some clue or it would be totaly misleading?
Sorry if the question is so silly
Regards.

 

[CapriRacer]

Thanks Again nice explanation,
While i replaced my A/T with H/T tyres, i had chance to stand on those tyres on the ground, they were not installed on the rims, A/T tyres were able stay without almost any deformation , keeping my weight 70KG, while H/T tyres flexed down immediately.
Do you think, if there are several tyres at the shop, trying to flex sidewall or other parts of tyre with hand may give some clue or it would be totaly misleading?
Sorry if the question is so silly
Regards.

It might, but it is the totality of the stiffness of the tire's sidewall that matters. For example, Michelin tends to use a very stiff tread area and a very stiff lower sidewall, but in between they use an almost flimsy upper sidewall. I would think that it would be difficult to sort this out.

 

[krzyss]

When I weighted 70kg I was young and beautiful.
Maybe it is a stretch - just young(er).

Krzys

 

[930.engineering]

.
Capri, why are you making things that overcomplicated? It's been
pretty clear what I was talking about. Just read postings #7 and 10.
.

 

[CapriRacer]

Capri, why are you making things that overcomplicated? It's been
pretty clear what I was talking about. Just read postings #7 and 10.

My experience is that some people don't go back and reference previous postings. If one makes a statement, there are enough people that will read only THAT statement and not realize what the context is. So a stand alone statement should be as accurate and as complete as possible. I've been down the road trying to explain why tires of the same size but different load ratings can be basically the same. Add the issue of SL vs XL and it's a little too complicated for many folks.