Another Tyre Thread - width considerations for on road driving with MT tyres

[agentmulder]

Hello all,

Due to a stupid fitment on a Defender new to me (225/75!) I'm getting a new set of tyres.

Although I do most of my driving on road, when I do go off I've really appreciated the extra grip the current (but small) MT tyre affords compared to an AT. I've only once lost grip on road in the wet with my current set, I'm ok with that and I cant rule out an AT wouldn't have been any better anyway. I'm also aware of the reduced longevity of an MT and are OK with that.

So... I'm sold on the BF Goodrich Mud-Terrain T/A KM2:

My query pertains to width:

235/85 vs. 265/75 - which are virtual equivalents in terms of diameter...

I'm leaning towards the standard 235 - mainly because of the (untested) theory that I prescribe to that a thinner tyre 'cuts' through mud to more solid ground compared to a wide. Also reduced cost per unit, and the less mass involved to get up to speed.

I'm not sold on the width in terms of aesthetics, but I suspect if I could compare I'd likely opt for the classic thinner look.

The actual question:

I'm interested in hearing your thoughts about what width would be best for the on road component of my driving?

 

[Turboman]

Hello all,

Due to a stupid fitment on a Defender new to me (225/75!) I'm getting a new set of tyres.

Although I do most of my driving on road, when I do go off I've really appreciated the extra grip the current (but small) MT tyre affords compared to an AT. I've only once lost grip on road in the wet with my current set, I'm ok with that and I cant rule out an AT wouldn't have been any better anyway. I'm also aware of the reduced longevity of an MT and are OK with that.

So... I'm sold on the BF Goodrich Mud-Terrain T/A KM2:

My query pertains to width:

235/85 vs. 265/75 - which are virtual equivalents in terms of diameter...

I'm leaning towards the standard 235 - mainly because of the (untested) theory that I prescribe to that a thinner tyre 'cuts' through mud to more solid ground compared to a wide. Also reduced cost per unit, and the less mass involved to get up to speed.

I'm not sold on the width in terms of aesthetics, but I suspect if I could compare I'd likely opt for the classic thinner look.

The actual question:

I'm interested in hearing your thoughts about what width would be best for the on road component of my driving?

Pretty much agree with your thinking about all that, and I would have thought the the BFGs are a good tyre, been around for ages.

My own take on the width would be simple. Off road, a wider tyre may give flotation, but that will always involve a loss of directional control, things that are floating dont usually steer very well.
On road, I cant see any particular advantage to width, either, surely they just give a bigger footprint and burn more fuel?

I think specs changed on later vehicles, but on my old thing I dont actually like profile tyres at all. I have 7.50R16, if I wanted bigger I would probably go with 9.00R16. To be fair, most of my usage is off road.

 

[mikegsxr]

255/85-16 MTs ? not monster truck wide, but suitably tall, no lift required, well except when it comes to lifting the bonnet...

 

[Vinlander]

At this time of year I'd go for grip and sidewall protection, but in summer I'd probably lean toward comfort and efficiency.

 

[Disco1BFG]

I run 235's, and agree with @Turboman , above. I think they are the right balance for on road comfort, off road grip for what I want to do.

Heavy off road use would probably require a rethink from the AT, to more of an MT - but you know that


Might find that other non LR approved sizes would have to be declared as a modification to your insurance too... ( if thats necessary in NZ ??)

 

[Turboman]

well except when it comes to lifting the bonnet...

Bodybuilding is very popular these days!

At this time of year I'd go for grip and sidewall protection, but in summer I'd probably lean toward comfort and efficiency.

That is exactly what I do. Semi aggresive muds for the farm in winter. Little ATs on another set of rims for summer.

I run 235's, and agree with @Turboman , above. I think they are the right balance for on road comfort, off road grip for what I want to do.

Heavy off road use would probably require a rethink from the AT, to more of an MT - but you know that


Might find that other non LR approved sizes would have to be declared as a modification to your insurance too... ( if thats necessary in NZ ??)

Guessing from username you might have a Disco. I think they were more designed for profile tyres. My comment was more about old 90/110 and steel wheel defenders. 7.50R16 was actually the only standard tyre option for 110s, no profile options at all.

Good point about the insurance, never really thought of that before, although I have standard anyway. I have no idea what legality and usual practice in NZ would be either?

 

[agentmulder]

Interesting regarding the insurance - I'm already running tyres that aren't standard ...

I'll opt out of 255 - mainly due to the fact that all the indoor parking lots I currently use with my 225/75 are (blimmin) close height wise already.

I might even need a recheck before I wedge myself into a sprinkler head with the 235's

 

[lucifus]

I've had 7.50 235 265 285 and 305 widths. On the road driving I couldn't tell the difference between the 4 smaller sizes. My reccomenfation would be to go for 265 over 235 purely on the fact the look slightly but not massively wider and you won't notice the difference off road. Also I've had 2 sets of the bfg km2. They are awesome in the mud and absolutely fine on the road.

 

[Coffeelandy]

I'm with Turbo. Narrower MT tyres cut into the ground especially on side slopes but they suffer on the road.
I've just fitted Goodyear Wrangler MT 235/85/16s and they work well on the road where I do most of my driving but like you I do off road occasionally for work and the grip is very comforting.

 

[agentmulder]

I looked into the legal side of things, and of course the info came via my insurer - so, in NZ any tyre that changes the manufacturers recommended diameter (31.7" for the 235/85) will need modification certification (the 'LVV cert').

And once you modify, this needs to be communicated to your insurer - which will up your premium.

Meanwhile I was at a LR mechanics this morning and had a good look around at all the various tyres installed, mostly 235 and 7.5 - zero 265, but two 255's - almost all in AT, except one of the 255's and one 235... The 255's noticeably grunty!

However, 235 it is

 

[crowmann]

Have had Good Year Wrangler 235 85 MT's on for nearly ten years.

Excellent tyre - good on and off road - had become tricky to source a couple of years ago as the old composition failed Euro noise tests - now all good, even LR started fitting them to the last year of production.