Without derailing Brian's thread here; the Grenadier wasn't designed for crawling, or, for that matter, ridiculous obstacles in general. It is a expedition/travel style vehicle, and for that use, especially in the overall global travel circles, you won't find most vehicles of this size on 35s or larger (ignoring the Icelandic agent putting 37s on these). My view on the "theory" is to make a vehicle that is capable, and if something like a tire gets destroyed in the middle of no where, you can easily find a replacement in the proper size. I understand that plenty of us will be moving to larger tires, increased ride height, etc; but as with most other vehicles, you're moving outside the design parameters, and have to expect that other problems will be created because of it.
If you want a midsize vehicle that swallows 37s without blinking an eye, a Jeep is definitely right for you. If you want to travel in (relative) comfort across thousands of miles of mixed terrain, then perhaps the Grenadier is a better fit
I get what you are saying, and I agree. But here comes a long post in which I want to add some nuance to the discussion.
The Jeep Wrangler JL - especially in Rubicon trim - was designed for rock crawling and for technical terrain. The Rubicon comes standard on 33-inch tires, with lockers front and rear, a disconnecting front sway bar, and a 4:1 low range. You can fit 35-inch tires with no other modifications. In addition, you can order a Rubicon with a 2-inch lift and 35-inch tires from the factory, and that will come with the gears of your choice (4.56 or 4.88) to compensate for the larger tires. Lastly, all JL Wranglers come with relatively long control arms, so that a lift and larger tires will not ruin the suspension geometry.
By comparison, the Grenadier - as a rock crawler - comes up short. To be clear, I am specifically comparing the two vehicles in regard to rock crawling / technical driving. I am not talking about payload, towing, or other aspects of an overland vehicle. When it comes to payload, towing, and strength of frame and some other components, the Grenadier has the Wrangler beat by quite a wide margin.
These two aspects of off-road driving (proficiency in technical terrain vs higher payload & towing capacity) are pretty much opposed, with gains in one area coming at a cost to performance in the other area. For example: (1) more flex usually means softer springs and lower payload & towing, (2) a lower transfer case ratio means better control in the rocks and steep climbs/descents but at the cost of a more widely applicable low-range for other off road conditions.
So yes - you are absolutely right to think about the Grenadier as an overlander, and not a rock crawler.
But it seems like Ineos wants to draw-in the rock crawling crowd with its advertising (see below, from page 17 of the U.S. brochure). When you look at the photo, read the header ("Rock Sliding"), and then read the text, one might be forgiven for expecting a little more readiness for rocks and technical terrain.
Its advertising, I get it. EDIT: But its more than just advertising. The Gren has many of the off-road hardware that rock crawlers look for: solid axles, recirculating ball steering, locking diffs, rock sliders from the factory.
But were there design choices that could have been made that would have prepared the Grenadier for more technical terrain
without detracting from its ability as an overlander? I would argue "yes".
First, they could have made the control arms longer. This would not detract from any of the Grenadier's current strengths, but it would make moving to a taller tire much easier. It sure sounds like a lot of owners are interested in going to a taller tire, and for many, a suspension lift to accommodate the taller tire. Longer control arms would make it much easier to maintain good on-road driving dynamics, and they would also facilitate articulation off road.
Second, they could have asked Carraro to produce an alternate gear set - purely as an
aftermarket option for those owners who are interested. Ideally, these would come installed from the factory, but let's ignore that option, since the Grenadier is a relatively low-volume vehicle, and this would add to production costs. All Ineos would have to do is advertise the alternate gears as an aftermarket option - perhaps with a link to Carraro or some retail outlet. Can you run larger tires on the Grenadier without re-gearing? Of course you can. Would it be better to re-gear for a 35-inch tire? Of course it would.
Suggestions 1 and 2 have absolutely
no negative impact on any of the Grenadier's current strengths. The vehicle would still be sold on 31.6-inch tires (easier to replace internationally), with 4:10 gears (the right choice for the stock tire size), and at the stock suspension height. In other words, these suggestions have a big upside, with no downside.
Third - and this
would impact the current version of the Grenadier - I think a slightly lower low-range would be a better fit for the vehicle. Maybe 3:1 instead of the current 2.5:1? For my use, I'd love to see it as low as 4:1, but I understand that many folk do not want it that low. But 2.5:1 is not low enough to provide sufficient engine braking on what most off-road rating systems describe as "moderate" descents. If you don't want to ride the brakes, you will have to use Hill Descent Control - which is a computer-controlled aid. The design-goal of the Grenadier was to build a more mechanical and less electronic vehicle, so I don't see that as a solution that fits with the design ethos of the vehicle.
In the spirit of improving the vehicle, not subjecting it - or anyone at Ineos - to unfair criticism.