Bosanek wrote: I researched a lot about larger tyre sizes on a Jimny. I read british, australian, south african and even german forums.
I discovered (and verified in practice) that the best "sensible" upgrade is to 205 / 75 / R15 size, just like many on those forums have recommended.
You essentially get approx 10 mm of extra ground clearance, more macho looking tyres, and stronger tyres when it comes to hitting potholes (less chance of tyres developing wobbles).
Gearing does change, but the general consensus is that it is hardly noticeable, if at all. The same goes for fuel consumption. I can attest to that from my own experience.
In theory, there should not be rubbing issues at all. However, in practice, you can expect some rubbing issues with the 2nd gen front bumper (2006-2012) and with front mudflaps, if you have those. However, they are easy to sort out (read more below).
According to south african forums, Suzuki's dealerships over there officially allow up to 3% of change in wheel diameter. Size 205 / 75 / R15 is 3,1% larger than 205 / 70 / R15, so it is officially supported over there (according to forum claims over there).
If you go any larger, like 195 / 80 or 215 / 75, you start an endeavor into a "murky" zone - you will probably get tyres scrubbing onto the wheel arches, front mudflaps or especially front bumper if you have a 2nd gen (2006-2012) bumper, and also the overall gearing changes so much that it noticeably affects car's road manners (acceleration performance, speedometer and tachometer accuracy, uphill pulling power and downhill braking power etc.). The fuel consumption is also affected.
If you go to the extreme, like 215 / 80 or 235 / 75, then you are entering a red light district without a cheap way out - you have to lift the car up, trim the wheel arches, install wheel spacers, change the transfer box, raise a new loan at the bank ....
Not to mention the additional wear and tear on the transmission, drivetrain, suspension, steering, and wheel hub assemblies. Also, get ready to visit the gas stations more often than you anticipated.
I personally upgraded from Goodyear Wrangler AT/SA+ from stock size of 205 / 70 / R15 to the same tyres in size 205 / 75 / R15. I have already ridden about 4 000 km on new tyres, on all kinds of terrain, from highways to mud bogs. It's a great psychological advantage knowing that you have 10 mm larger ...... ground clearance.
Before I installed new tyres, I measured and determined that my new tyres would probably catch on the main screw on my factory mudflaps, so I preventively disassembled the mudflaps, shortened the plastic spacer behind the mud flaps by approx 10 mm and then reinstalled everything.
As my 2nd gen front bumper had sagged slightly, I determined that the new tyres would probably catch on the bottom of the front bumper. So I trimmed about 15 mm from the bottom of the bumper with a grinder. The change is unnoticeable and invisible, and does not "hurt" at all.
Both trimmings took me about 10 minutes total time to do, and I am not a savvy mechanic.
New tyres fitted superbly, and it turned out that my trims to the bumper and mudflaps were justified.
I'd have to respectfully disagree with 205/75's being the sweet spot. From my experience (I use the Jimny 50% on-road, 30% on forestry roads, and 20% on rough tracks such as quad-bike trails, etc) I get on perfectly with 215/75's. Gearing is minimally affected, top end speed is still much the same. Greater than 65ish in a Jimny on any tyres is probably not a great idea anyway.
While having said that 215/75s are good, I'd say that if gearing is still a concern, then 195/80's could also be considered. Smaller than this is no good, as lack of ground clearance can be said to outweigh any advantages of the smaller tyres i.t.o. gearing (which is probably the only advantage of smaller tyres anywaym, unless someone else can think of anything).
Obviously, the user's individual demands do make the above statements relative, but I'd say that my comments would apply to any Jimny owner who uses their vehicle for terrain beyond gravel roads.
