When I changed my old Disco's tires to KO2's, I left the OEM spare as is. I figured it wouldn't see more use than one of those compact spares would provide, and that it should be good enough to get back to a road, etc. I never had a flat with the KO2's, so I never got to try out that theory.

Stupid idea, right? Yes, of course!

But still, with open diffs all around, the theory was that a small difference in diameter, hence a small difference in rotational speeds, etc., shouldn't be too much of an issue at trail speeds (but not so on the highway, obviously).

Any commentary about this? Asking for a friend who will soon change to KO3's.

 

It is always good to have the spare the same as all other tires on a Defender. Whilst you will be ok having a different spare, a lot of that decision depends on your style of driving and how far you take your vehicle off road. If most of the driving is around town and highway driving, you will be ok. I personally would not want to be off roading with a different spare.

 

My spare matches. 5 tires all the same. 5 tire rotation so all get used equally. No downside to having 5 tires. 20% more life on a set so no cost saving over the long haul. You always have a spare that's no different to the other 4, and (very much a secondary concern), it looks better.

If you end up trashing a tire, your new one wont match the other 3. Maybe need to buy 2.

Get 4 only and you always have a spare that's different. That could really but a damper on a fun trip. Will it get you home, most probably. Will it be a nuisance when needed. Yes. I have KO2s. One has a plug. a few have some minor trail damage. A great tire. I'm sure KO3s will be too.

 

This scenario has actually happened to me twice and I lived to tell the tale.

once I drove 700 miles home in my Range Rover sport with a tire of a different width and slightly different diameter.

another time I did about 100 miles home in my Defender V8 after ripping not one, but 2 Goodyear wranglers on the same rock, limping off the trail by pumping the less damaged one back up every few miles, and then hit a rural tire shop that didn’t have the exact size in stock.

both times the minimal difference in diameter (I wanna say like .1 inch) caused no damage to the diffs. These are fairly tough vehicles that can take a lickin and keep on tickin.

that said while it’s doable in a pinch, I now am loaded for bear with KO2 and a full sized matched spare.

 

I also buy 5 winter tires. Winter tires sell out and if you destroy a sidewall on a pothole, it may be hard to find a matching tire in mid-winter. The only dilemma is how to mount the directional spare tire. I go with "right" since most big potholes are usually closer to the shoulder.

 

The point about open diffs is that they don't care if one wheel is spinning faster than the other (hence also if one wheel is taller than the other). Indeed, that's their whole point, since as you make a turn, one wheel must spin more quickly than the other. Differentials are used to allow just that.

On my old Disco, with true open diffs all around (it did have a center locker), I wasn't too worried. However, the center differentials on these are electronically controlled, and the TC system can modulate all four wheel's speed, too. So while I still think it should be fine (none of those systems should interfere with modest rotational speed differences), it's possibly a bit more tricky of a question.

Anyway, I'm only discussing this out of curiosity. I would certainly swap all 5. I've just been wondering how well it would work - or not work - in a pinch.

But also: How do you like the KO2's on this car?

 

Highly recommend the KO2. Minimal tradeoffs in fuel economy and tire noise to the point that i’m not sure I could tell in a blind test.

maximal gains in sidewall strength (get the 10ply) and in cool looks. It’s a no brainer compared to the OEMs.