It's a very common claim - so they say, wheeled vehicles [especially 8x8s] are able to self-deploy 1,500 km or more and then fight, thus making them wonderous bits of kit. You don't need light/heavy equipment transporters (LET/HET - trucks with really big capacity trailers for carrying tanks and other AFV), you could just order a brigade of wheeled AFV to drive to Eastern Europe tomorrow and off it goes under it's own steam. Brilliant! Is that something that holds up to scrutiny though?
Yes and no. Mostly no. Anything can self deploy, so yes its true, but whether you can tolerate the costs and implications of doing so is generally a no.
AFVs are big wheeled things, so the temptation is to look at them through the same thought processes as trucks, specifically long haul road trucks, because they're huge and have wheels too, and you see them all the time so it's what your brain jumps to. But this is a really flawed line of thinking.
AFV are closer to their tracked relatives than their road going cousins. They are very heavy, they are packed with unpleasant loading (turrets in particular are a massive weight high up in the middle of the vehicle and irritatingly turn and shove recoil forces in weird directions). Their usage profile is often brutal, moving aggressively over very challenging terrain to carry out battlefield missions with very harsh acceleration, braking and turning movements. The wear and tear on their drivelines and the vehicle as a whole is just horrendous. Militarised is a term for a reason, and big armoured AFV are very much a military product.
What that means is that a truck that might happily do tens of thousands of miles between major service intervals sets an expectation that wheeled AFV are similar. But big 8x8s can see significant failures at surprisingly low mileage.
A 2017 study into the Stryker 8x8 showed an average mean miles between system abort (MMBSA), meaning something breaks that is critical to the vehicle being able to operate its mission any more, as low as 982 miles (c.1,500 km) in operational testing. This was much lower than the developmental testing had suggested it would be, showing reality can be quite different to trials.
Also using Stryker as a case study, the US Army demonstrated the challenges that need to be overcome when sending 8x8s on long road marches when it moved 153 vehicles including Strykers on a 798 km march through Europe in 2016.
Over the course of the 36 hour, 800 km march there were 15 immobilised vehicles due to faults, and a further 20 of a significant level that required immediate fixes to avoid immobilisation. One vehicle could not be fixed and had to be recovered. That's about a quarter of the fleet that failed at some point.
It was also only achieved with significant non-organic support that included host nation pre-positioned refuelling points, civilian tractor trailers for recovery (the organic wreckers and trailers were not of sufficient size and capacity for the Strykers in the formation), and one instance of a helicopter having to bring forward urgent spares.
The story linked above goes into more detail, including notes that stated actually supporting a move of this scale required the support vehicles to be at or beyond their weight capacities, and that the fuelling assumptions were significantly short as they did not account for air conditioning, additional armour packages and a the scale of the real world kit people put on their vehicles that pushed them to the GVW limits. Many vehicles had to "use fuel cans to make it to the next refuel point, especially with various stops to complete maintenance and to wait for police escorts at border crossings."
The substantial weight of personnel and equipment "stressed older vehicles and caused multiple braking, cooling, and suspension breakdowns along the route. Wheeled sustainment and cargo-carrying vehicles had the most breakdowns. These repairs were resolved with hand tools, but they caused significant delays within the movement window."
Now we can assume a modern 8x8, being several decades newer in design and featuring many improved technologies will be better than these experiences, and have a higher MMBSA figure. But not by many factors. Such data is not forthcoming from manufacturers, but let's assume it several factors higher - its still likely to be sub 3,000 km (at best) in the real world with varying age and mileage vehicles. That's ok, these are big maintenance intensive military vehicles, but it's also a best case, and is still not enough more than the road march to feel comfortable about things.
Someone will doubtless point to a trial somewhere where a vehicle did 4,000+ km, but it will have been selected and specifically prepared for that trial with unrealistic levels of scrutiny and support. Reality isn't that convenient. The vehicles will not be in perfect, 'just exited a major service and refurbish' condition when they get called on. They will be in a range of conditions, and some will be close to their MMBSA milestones. That's just life.
And that means you're going to lose vehicles on the way, so make sure you pack a sustainment fleet and do some predictive maintenance work to mitigate anticipated failures and bring truckloads of spares for the things you know may break. That's all burden for the logistical tail on this deployment.
When you do arrive, your vehicles, even if they were fresh at departure, are at or near their service intervals and failure predictions. In a modern age of predictive maintenance we don't wait for things to fail, so there will be a huge range of maintenance tasks now due. Assuming we can ignore a few because its war and we need to crack on, you still have a fleet of vehicles that are by no means in optimum state about to embark on an extended combat operation that will test them significantly. None of this is ideal.
But say you ignore that angle for now and do road march an 8x8 fleet 1,500 km to Eastern Europe (which is actually pushing 3,000 km from the furthest start point in the UK, but let's keep it best case and start in Germany). We know Eastern Europe has a lot of wet and soft soil areas, so you want good off road tyres when you get there, or your terrain accessibility is going to be very poor and the enemy will exploit that to destroy you on predictable routes of manoeuvre.
But if you do fit good off-road tyres at the start, they will be shredded before you get there. A heavy duty tyre like a Michelin XML will wear incredibly fast over hundreds of road miles in one go. By the time you get there you've lost most if not all your tread depth and your mobility is totally compromised. Ok, instead we'll fit road optimised tyres and swap them for off-road at the destination.
Either way, now you need to replace all your tyres when you get there. These are not small components. A tyre for a modern 8x8 like a Boxer is 110 kg, 1.3 metres across and half a metre thick. And you need eight of them per vehicle in the formation.
This alone is going to be dozens and dozens of trucks following your formation, just full of tyres - for something like a single UK Brigade Combat Team (BCT) with the anticipated 326 Boxers it requires at full strength we are talking about a minimum of 287 tonnes of tyres taking up 2,200 m³, assuming just a single set per vehicle and no need for spares for accidental damage nor for the combat operations ahead.
You also need the tools and machinery (ideally forklifts and cranes) to rapidly cycle several hundred vehicles through a tyre change cycle. Which is more trucks and people. The logistic tail is huge, just to get there at all.
So at the end of this adventure we are looking at heavily worn AFV, many requiring significant maintenance or repair work, accompanied by the better part of a hundred-odd trucks of tyres and spare parts, all needing a lot of work and then a good rest for all involved. Except we have just arrived in a war zone and need to fight a campaign. Are we sure this was a good idea?
So, can you road march wheeled AFV thousands of kilometres to fight a war? Sure. You can do the same with tracked AFV too, as it happens.
But both will suffer (and good Lord the tracked ones would suffer, anyone who ever genuinely believed the UK Strike concept of Ajax doing 3,000 km to self-deploy too on tracks were utterly mad, we have to recognise that) and will arrive with many issues that need work. The logistics burden would be very high, and in broad terms it's just not a great plan at all.
Transport AFVs on LETs and HETs, on trains and boats. Only make them drive when they have to, else the implications and costs, literal and figurative, are very dear indeed.
Note: If you like wheeled AFVs, check out my primer on CTIS and tyre choice with regard to mobility and any equivalencies to tracked AFVs, which you can read here.