Has anyone upgraded gen 4 tyres without going bigger?

I'll try to anwser a few of the concerns raised here about the so called lethal BFG tyres on a Jimny. We myself & Bigjimny run 3 Gen 4 Jimnys on BFG 215/75/R15 KM3 mud terrain tyres. Why did we choose those tyres? Simply we liked the look of them and also heard good reviews on how they performed on the road as we don't use our new Jimnys off road so good road manners is key. 

1. Can you feel a difference between stock tyres and 215/75/R15 Mud terrains? 
Answer is yes you absolutely can. When we got our first lcv jimny we ran that on the stock tyres for a little while. Going back to back between the stock & modified car I could feel that the stock car felt lighter, more nimble and quicker off the mark. Now if couldn't run a back to back comparison then I think you would struggle to know any difference. 

2. Are they lethal and how do they handle in the wet or cold weather?
Answer is all mud terrains won't be the best when it comes to road use however We (myself and my dad) have never had any issue with our mud terrains out in the wet. I drive just the same and feel no difference with the cars performance. Obviously in very wet almost flooded conditions extra care is needed in a Jimny as it will get drawn into big puddles through the steering but this goes for any Jimny stock or modified. Same goes for icey cold conditions. Never had an issue but more care is needed and i wouldn't like to hit Ice or stop in a hurry but again I wouldn't feel any safer in a stock Jimny. In no way do I consider BFG KM3 mud terrains lethal. 

3. How do they handle over bumps?
Answer is I think they do better in the potholes having the chunky tread although two of my Jimnys do have Lift kits aswell so I also believe changing the suspension does have a big effect over how the car handles. I think my lifted Jimnys handle bumps better than my dads unlifted car but tbh in reality they are pretty close to each other and again you would only really tell by directly swapping between cars. I should also add that different lift kits also differ the handling. My two run different lift kits and whilst they are pretty similar one does feel firmer over bumps and the other is more wobbly. 

4. Are My Jimnys more capable in an offroad enviroment over a stock one. 
Anwser is that really depends on the enviroment thown at it. Ground clearence wise there isn't really anything between my lifted jimnys & a stock car so in deep mud and ruts I wouldn't really think my Jimnys stand a much better chance in a bog hole type situation. Mud terrains may help but they won't be much help if the Jimny is sitting on its axles same as a stock Jimny. On wet grass I would like to think my Mud terrains stand a better chance over the stock tyres but I wouldn't under estimate the stock car especially if my mud Tyres were to clog up with mud making them really slippery. In a cross axle articulation type of enviroment my lifted Jimnys would do better at flexing as I have more travel/ room to play with in my wheel arches due to having a lift.  

5. How do the handle on the road?
Anwser is we really like them. You wouldn't really be able to tell your driving a car with Mud Tyres. Yes there is a bit of road noise (This can also depend on the type of road your driving on) but the reality is I can hardly tell unless you go looking for the road noise. Often I have the fan running or radio on so that masks any noise but often I sit in quiet and don't really think about any noise coming from my tyres. Perhaps I'm use to it I don't know. 

Hopefully this all makes sense. 

Some good info here:

Been driving with MT's for several years and worn out my last set now so will need new tyres.
As i use the car for overlanding mostly the last years I have been thinking maybe AT's but this video and my own MT-experience makes me very uncertain.

I do not like my old worn out and now retired MT's in the rain but old AT's are not so great either. the MT's where not so bad when new and this is the same for all tyres.
They all get more "lethal" with age and especially in the colder weather.
AT's can be used for light winter duty when they are new so that is a pro for me for the end of seasons when conditions are uncertain.
I would strongly recommend not to use MT's in any winter conditions.
Yes i live in Norway but here on the coast the average winter temperature is on the plus side, but still.
Do not expect to get a winter tyre when you buy an MT tyre.  
The BFG AT is not a winter tyre but still much better than the MT, and only the first 3-4 years of service life before they get too hard.

And for the BFG's I had them for years and years and know their limits.

But i also know their possibilities and I just love how I get around on any terrain and how I get so much further than some others. Could be my car is better but at least I know it is not the tyres holding me back, and they get me thru where others get stuck.
And so far they have coped with 0.3-0.5 bar tyre pressure offroad without getting hopelessly broken.

yakuza wrote:

The BFG AT is not a winter tyre

They are 3 Peak Rated, so should be fine in many wintery conditions and certainly pass certain official tests to be counted as an approved tyre for winter use.

yakuza wrote:

I would strongly recommend not to use MT's in any winter conditions.

I think this is very geographically dependant.

In cold parts of the World, like where you are it may be true. However, in places like the UK an MT can work brilliantly in the snow.

We tend to only get snow occasionally and some parts of the UK may go a number of years without any snow. When it snows it comes down quickly, is fresh, but often is gone completely within a few hours to max a day or so. It never gets frosted or compacted or another layer of snow on top really. Certainly not in many parts of the country.

We also get 2 different types of snow, depending on if it comes from the North, which is usually a dry snow and often like polystyrene beads. Or if is rain from the South coming up from France and hitting cold air, producing much wetter snow. The Southern half of the country the wetter snow is more common.

Through experience of driving many MT shod vehicles and AT ones, is that the MT's work way better in this kind of fresh wet snow. The lugs dig in lovely and massively enhance traction, while an AT like on mud, will slide more so and not bite as well into the snow.

Other benefits of MTs are, that the ground is often wet and muddy under the snow. So if you need to drive up a bank, verge or across a snow covered field. Should you break through the snow, the MT will give way more traction than an AT on the underlying ground.


 

You can see here how in this type of snow how well the MT bites into the snow. An AT tends to float somewhat more.

If the snow is heavily compacted, frosted or driving on ice it might well be a different story, but local snowy conditions covering a huge populace of UK, MTs would work very very well in the snow.

Hello,

So the more videos I watch the more and more I am convinced that you do not need the 215s. I will be navigating mostly dry and sometimes steep terrain. I think same size but AT will be plenty (now choosing which ones will be another struggle)
Watched 300bhp Aldermaston 2022 video and the only places I think a dunlop at20s would struggle are the slight up hills. Minute 7 and especially struggle min 11:20. But I think with speed most obstacles on stock can be handled in that video. Basically the Jimny is extremely capable as it is.
Now I want to explore what deflating does to the tire performance off road

I have run MT's on my daily drivers for a number of years and found them only marginally worse than road tires or in some cases better!

I suspect the quality of the tire (remoulds?), inflation and other mechanical problems (shocks, kingpins, steering damper etc.) are having as much impact on people's perception of tire performance than the tire itself.

In relation to the original question, my new Gen 4 Jimny is running 235/75R15 BFG AT's on standard suspension - whilst I haven't tested for clearance - under normal road use I haven't seen any issues.  I intend to upgrade to a 2" OME lift ASAP before doing any offroad work!

Stoo