Grenadier wrote:

Quick question. Is there any advantage to using a 60 profile KO2 over a 65 or vice versa, on an 18” rim?

I’m not planning to do any major off roading or overlanding in the near future, and use my DC as a road biased daily driver, so just wondering what advantages there might be going down one route or t’other?

Immediate advantage for the smaller profile is a £100 saving. Every little helps as they say. Or, why spend £100 on extra rubber when it can be put towards other parts or 20 pints of ale?

But any other advantages?

Fuel?
Noise?
Rolling resistance?

Nothing?

And how much will a 5mm drop affect the speedo, or not at all?

Thoughts?

Aspect ratio aside because LRA has answered that.

Some food for thought... Perhaps...

In general, taller = more engine effort to turn the tyres and the longer the gears are. Not a problem on the flat but in hillier terrain longer gears can be a pain, especially if you have "upgraded" to the 1:1.22 Disco gearing. Add weight in to the vehicle or tow a heavy trailer and the effect is just multiplied. I forget what era Defender you have Grenadier.

Wider tyres = vaguer turning, as in they are less responsive and can create under steer. The extra footprint is good for braking, good in the sand, good on rocky terrain, not so good in heavy rain with standing water on the road and can reduce MPG due to rolling resistance. Whether wider is better in mud and snow than skinny is a topic that has been debated over and over. Six of one, half dozen of the other and utterly depends on whether there is a hard base under the mud or if it is bottomless.

Combining wide and tall can really decrease MPG, especially in hilly regions.

Tyres with a smaller aspect ratio will feel more positive on the road (less flex in the side walls) but may increase jolt-like vibrations if the road is rough or textured.

Wider are likely to be noisier on the road than narrow tyres for the same tread style (AT, MT etc). They are also more likely to track in lorry grooves on the motorways.

Generally, MT will be noisier than AT which will be noise than road biased and in the same order for increasing MPG, feel in the corners (so less under steer) and decreasing braking distance.

The more I drive Defenders (especially in the UK/Wales under our conditions) the more I am certain that in order to get the best MPG, braking, cornering, component wear and comfort it is best to keep the tyre size to as close to the standard LR size as possible. So a 235/85/16 or 265/75/16. Where I live, which is a mini version of where you live (although we will never openly admit to that...) it is the perfect combination for almost all driving and conditions. They are also less expensive, generally...

jpboost wrote:

For context, in 16" sizes, there are lots of reports that cars shod with 235/85/16 are a nicer drive than those with 265/75/16. But again, that doesn't stop a lot of people (including me at times) fitting the latter as they look chunkier.

I concur... I had 265/75s on my 110 for a while... indeed it looked good but didn't handle that well (or might I say, it seemed to handle ok until....) i fitted 235/85's and thought blimey, this handles well now in comparison to the old tyres.

but the 235's look a little wimpy in comparison