33" vs 35" regarding comfort

[Cañonero]

A friend just got him an 80 that has the same suspension setup as mine, but with 35x12.5x15 tires instead of the 285/75/16 I'm running on mine.

The thing is that his ride is quite more comfortable than mine, so, either his suspension is worn off (it looks older than mine) and it has softened or the 35" tires give a softer ride.

He was even running them at 40 psi, while I was running mine at 35 psi and his was noticiably more comfortable. We did some passes over some road bumps and the shock with his was softer too.

What do you think, will these tires make such a difference in comfort or is more likely a worn off suspension?

 

[retrofive]

What year was his? LC or LX?

 

[kidglove13]

I run both on my 94 FZJ and the 35's seem to ride softer at the same pressure as the 33's.
FWIW

 

[Nay]

When I was reading your post, before I got to your sig line, my first thought was "I bet he has BFG AT's". Bingo.

33" BFG AT's at 35 PSI ride like absolute crap as far as I am concerned (and I have had this basic tire size on two different rigs). A bigger tire with a much better sidewall will ride much better. I would take my 37" trxus MT's for city comfort any day of the week over BFG AT's, because to get the BFG's to ride nice you need a low enough PSI that they start to get sloppy.

When I first went to Trxus MT's about 6 years ago, I was really worried about all of the negative potential, and my first extremely pleasant surprise was how dramatically ride comfort improved as that was a significant concern.

It was, and remains, a laugh out loud difference. One of many reasons I never looked back to (BFG) AT's.

 

[Cañonero]

Thank you guys.

His is 1994 Land Cruiser HDJ80, no extra weight added. It's a LDH and mine is a RHD.

 

[Cañonero]

When I was reading your post, before I got to your sig line, my first thought was "I bet he has BFG AT's". Bingo.

33" BFG AT's at 35 PSI ride like absolute crap as far as I am concerned (and I have had this basic tire size on two different rigs). A bigger tire with a much better sidewall will ride much better. I would take my 37" trxus MT's for city comfort any day of the week over BFG AT's, because to get the BFG's to ride nice you need a low enough PSI that they start to get sloppy.

When I first went to Trxus MT's about 6 years ago, I was really worried about all of the negative potential, and my first extremely pleasant surprise was how dramatically ride comfort improved as that was a significant concern.

It was, and remains, a laugh out loud difference. One of many reasons I never looked back to (BFG) AT's.

Sorry Nay, I was writing the same time as you.

I didn't know BFG AT's rode that bad. They were OK with my old springs, but with the HD springs the ride is not very comfortable at all.

By the way, my friend's tires are the BFG MT KM2.

 

[corsair23]

Easy - Swap tires and compare apples to apples and take all of the guessing about worn suspensions etc. out of the equation

 

[Nay]

Sorry Nay, I was writing the same time as you.

I didn't know BFG AT's rode that bad. They were OK with my old springs, but with the HD springs the ride is not very comfortable at all.

By the way, my friend's tires are the BFG MT KM2.

The KM2's are going to be a substantially softer compound, no surprise they ride better.

Good idea to swap and try if you can - you don't really want your tires trying to make up for HD springs/shocks.

My comments were relative - BFG AT's are not terrible, but you can certainly improve substantially with a softer compound tire that has better sidewalls. Not sure your experience is really the tires vs. the HD spring change.

 

[Tapage]

It was, and remains, a laugh out loud difference. One of many reasons I never looked back to (BFG) AT's.

how much miles ( life span ) are you getting out from your Trxuss tires .?

 

[BrotherRob]

LHD rig ride better.;p

Nay nailed it. Tire type and make has far more impact on ride that size.

X2 on the BFG ATs. My Taco had them when I got it. They lasted about 100 miles before I kick them to the curb.

 

[Cañonero]

Swaping them is definetly a good idea, I will ask my friend.

I'm definetly going to change to BFG MT (or maybe another MT) and I'm considering moving up to 35" with all the advantages and disadvantages, so if they will give a better comfort is another thing to put in the scale.

Anyway you got me doubting now, if they ride better on my truck I won't know if it's for the size difference or for the type of tire.

I also wonder how about the ride of a 315/75/16 compared with 35x12.5x15?, I will buy aluminium wheels anycase and I have the small brakes, so I can use either of them.

 

[Nay]

I also wonder how about the ride of a 315/75/16 compared with 35x12.5x15?, I will buy aluminium wheels anycase and I have the small brakes, so I can use either of them.

None, if you could find both in the same tire. Mine are load range E. The price here is treadlife (to the question above). I get about 20K miles to half tread, which takes me close to 3 years and is the time I like to sell tires both for age and performance.

 

[greentruck]

With BFG MT KM2s, some of the difference has to do with the ply rating. In 255/85 (33.3") and 285/75 R16s (33.1"), both are E, while the 315/75 (34.8) has a D carcass. Getting larger yet, the 345/75 R16 (36.4") is a D, too, while the (37.6") 365/75 R16 is a C.

Then there is the 305/75 R16. 33.1" and only a D. Anyone know if those ride better than the other two, more popular 33s? It's not like the 305's 2910 pound capacity per tire (between 500 and 750 lbs less than its two 33" sisters) can't hold up an 80.

Can't say I have any side by side experience in most of those, but I'd imagine some substantial differences in ride quality on the ply rating basis alone.

 

[Cañonero]

I'm not sure about if a lower rating tire would be more comfortable than a higher rating.

For example, comparing a 305/70/16 and a 285/75/16:


305/70/16: 2910 lbs at 50 psi.
285/75/16: 3750 lbs at 80 psi.


3750-----------------80
x-------------------50

x=2343,74

I don't know if it works this way, but if it does, at 50 psi the D rating tire would actually have a higher load capacity than the E rating.

 

[greentruck]

Canonero,
The ply rating referred to actual plys of fabric in the age before radials. Now it's just a number denoting load carrying capacity. I presume a larger tire, with a lower load carrying capacity (lower ply rating) at a lower tire pressure, would give a better ride than a shorter tire, with a higher load carrying capacity, at a higher pressure.

I haven't cross-referenced these with actuall @ss-in-the-seat experience, but it seems to me that this would account for at least part of the reason why some taller tires give a better ride than shorter versions of the same design.

 

[Ebag333]

The ply rating referred to actual plys of fabric in the age before radials. Now it's just a number denoting load carrying capacity.

There is ply rating, and then there is number of ply's. Ply rating is an arbitrary number assigned to give you an idea of the toughness of the sidewalls. Number of ply is something else entirely.

For example, Tire Rack usually says the number of ply's. On the General Grabber AT2's:

The tire's internal structure includes twin steel belts (some sizes reinforced with nylon) on top of a two-ply polyester cord body to combine strength and durability with a quiet ride.

The sidewall truly is two-ply (I know, I've had the opportunity to see for myself ).

Now that doesn't mean that all ply's are created equal. Some tires with 2 ply have stiffer side walls than tires with 3 ply construction.

Now it's just a number denoting load carrying capacity. I presume a larger tire, with a lower load carrying capacity (lower ply rating) at a lower tire pressure, would give a better ride than a shorter tire, with a higher load carrying capacity, at a higher pressure.

This is absolutely correct, as a general rule. As with all rules there are exceptions, but it's a good rule of thumb.

 

[Cañonero]

So we swapped tires and yes, mine rides better with the 35", but not as soft as his, so his suspension must be worn out also.

What really surprised me is that I didn't notice any lack of power at all, at least for the short while I drove it, and also, it looks terrific with the 35"!

The bigger suprise, anyway, is that we weighed both tires and my 285/75/16 on steel wheel weights 44.8 kg and the 35x12.5x15 on aluminium wheels weights only 36.5 kg, so surprisingly enough, the 35" are 18 lbs lighter. I believe the smaller wheel and the aluminium play a big role here.

I also suspect this weight thing has helped too not to feel any lack of power after swapping to 35".

After this I'm definetly leaning to 35" for the next tire change.

 

[Kalawang]

So we swapped tires and yes, mine rides better with the 35", but not as soft as his, so his suspension must be worn out also.

What really surprised me is that I didn't notice any lack of power at all, at least for the short while I drove it, and also, it looks terrific with the 35"!

The bigger suprise, anyway, is that we weighed both tires and my 285/75/16 on steel wheel weights 44.8 kg and the 35x12.5x15 on aluminium wheels weights only 36.5 kg, so surprisingly enough, the 35" are 18 lbs lighter. I believe the smaller wheel and the aluminium play a big role here.

I also suspect this weight thing has helped too not to feel any lack of power after swapping to 35".

After this I'm definetly leaning to 35" for the next tire change.

It's possible he has softer shocks or just shocks that fit correctly. They make a gigantic difference to ride and drive comfort. Good springs don't wear out quickly enough to justify many of the changes people make. Most simple test is to stick your tires on his and see if the ride becomes more harsh.

You also have to look at the ply of the tires. A 6 or 8 ply tire will always ride more harsh than a 4 ply.


Kalawang

 

[Nay]

You also have to look at the ply of the tires. A 6 or 8 ply tire will always ride more harsh than a 4 ply.

Not true. Tread compound and a higher load rating that allows closer to stock PSI are a far greater factor than # of plies.

I will say it again: I would take my 37" Trxus for road comfort of 285/75/16 BFG AT's any day of the week, and that is a Load Range E 10 Ply tire that weighs about 81 lbs a tire.

 

[ROLDS]

I was running 35s Q78s for my off road tires and thought I was going to lose my hearing when driving more than 40 mph. My Q78s are for sale right now and just switched from road tires from 285's to 315's from Nitto Terra Grappler and my truck is like driving a Cadillac now. I just got back from Uwharrie and was suprised how well the 315's did.