Another tire/wheel thread: 19" vs 18"

[catman]

I had to go back to the post below to remember I had researched this a bit when I first bought them, there are photos of them being tested when they were launched and some sizes are beefier - the 255/55/19 was just released at the end of 2019, so they may have modified it for this size considering it is most commonly a street tire size...

The pics in the link below are when new, but it was snowy/wet and they are dirty so it hides the tread.

Review of Continental TerrainContact A/T

One has a more square edge:

 

[cperez]

I would't air one down on rocks, though. There is no 19" tire that comes with a strong enough sidewall to withstand a sharp rock. Airing down a tire generates considerable additional sidewall exposure, and I personally think the risk far outweighs the reward.

I agree with this even in wooded, muddy trail conditions with the mere possibility of random protruding rocks. I'm convinced I lost a Conti TerrainContact to a sidewall tear because I followed the landowner's advice to air down against my instincts.

 

[hatch]

And you’d all echo the don’t air down advice (other than in sand) for even a tire like the Wrangler Duratrac?

I just get more and more aggravated by LR’s decision to go to 19/20 on the LR4. It’s not like I even get my truck in those conditions more than a few times a year, but there’s no reason whatsoever for the sacrifice.

 

[ryanjl]

And you’d all echo the don’t air down advice (other than in sand) for even a tire like the Wrangler Duratrac?

I just get more and more aggravated by LR’s decision to go to 19/20 on the LR4. It’s not like I even get my truck in those conditions more than a few times a year, but there’s no reason whatsoever for the sacrifice.

Sidewall is still weak on the 19" Duratrac.

 

[hatch]

And these worries go away just by dropping to 18s?

Personally, I'd be keen to see LR offering 16s.

 

[ryanjl]

18" wheels and E-rated tires.

 

[Bryan Jones]

And you’d all echo the don’t air down advice (other than in sand) for even a tire like the Wrangler Duratrac?

I just get more and more aggravated by LR’s decision to go to 19/20 on the LR4. It’s not like I even get my truck in those conditions more than a few times a year, but there’s no reason whatsoever for the sacrifice.

I've aired down my 19's, actually popped a sidewall (not aired down) I have videos of aired down (36-40 PSI)

 

[mpinco]

18" wheels and E-rated tires.

This

 

[BikePilot]

This

Ditto. 18s are still fairly short sidewalls and not going to flex like a 37 " tire on a 15" rim, but getting to 18" means you can get real truck tires. The sidewalls on an e rated mud terrain tire Re massively thicker and stronger than you will find on xl rated 19s. IIRC my 19" Michelin tires weigh 30lbs, my 18" coopers are around 55lbs. That's a lot more rubber. It's completely silly that they came with 19s. 18s suit it so much better.

 

[gsxr]

It's completely silly that they came with 19s. 18s suit it so much better.

For serious off-road use, yes, the 19's may be silly. But I suspect 75%+ of LR4's produced spend 99% of their life on actual roads, or at least in situations that don't require airing down. Enabling easy fitment of 55-lb, 18", high-load-rated tires just wasn't a priority when designed and built. Other factors must have pushed the decision towards the 19's.

Why are the brakes so large? Because the truck (not car) weighs nearly 3 tons by itself and is often used for towing; and it has 375hp too. Could JLR have designed an equivalent braking system that would have fit under an 18" wheel? Probably, but again it was either not a priority, and/or would have driven costs up further. We're lucky that ANY 18" wheels fit at all.

Disclaimer: Our LR4 rarely ventures off pavement, and the stock 19's work fine for our needs. But I do understand why some folks need 18" E-rated rubber.