BMW Motorrad's renaissance over the last 15 years has come on the back of a massive worldwide boom in adventure bike sales. The firm's R1200GS both sparked the growth in that market and continues to dominate it while the company's smaller F-series GS models bolster its mid-range adventure offerings.

In 2019 we’re going to see the most radical overhaul of the Bavarian firm’s adventure offerings in years, with new R1250GS and R1250GS Adventure machines replacing its range-topping R1200 duo, and a new F850GS Adventure (pictured) slotting into the top of the F-series line-up.

Starting with the smaller bike, the picture you see here comes from BMW’s design patent for the F 850 GS Adventure. While it looks like a poor Xerox copy (that’s exactly what it is), the image still gives a pretty clear look at the changes that separate the F 850 GS Adventure from this year’s new F850GS.

Visual changes include a stubbier, wider ‘beak’ above the front wheel, ahead of a wider front cowl and taller, adjustable screen. Moving back, we can see a significantly larger fuel tank – probably around 6.5 gallons, up from the 4 gallons of the basic F850GS – above extended fairing side panel. A crash bar around the engine, and a new tubular steel luggage rack at the back, complete the cosmetic revamp.

F850GS Adventure
2019 BMW F850GS AdventureCourtesy of BMW

When it comes to what lies underneath, we’ve seen European type-approval documents for the new F850GS Adventure that give detailed specifications, long before BMW has officially revealed them.

The leaked specs reveal that the bike’s 853cc parallel twin - a completely new design, unrelated to the F800 engine that preceded it – is taken straight from the F850GS that was first revealed a year ago. As on that bike, it makes 95hp at 8250rpm on premium gas, or 90hp and 8000rpm on regular (87 octane) fuel.

Similarly, the pressed-steel chassis is identical to that of the F850GS and F750GS.

But the F850GS Adventure is going to feel bigger. As well as the oversized tank, its bars are 2in wider than the F850GS’s at 37in, and the top of the screen sits more than 5in higher at nearly 58in. The changes help knock the bike’s top speed down from the F850GS’ 130mph to 122mph, or 119mph if it’s in low-octane, 90hp mode.

You’ll feel the alterations in the weight, too; where the F850GS comes in at 505lb complete with a full tank of fuel, the Adventure version is 538lb. That’s coincidentally exactly the same weight as the current, 2018-spec R1200GS – the next rung up the BMW adventure bike ladder. But come 2019 that model’s changing as well, to the R1250GS, and once again we’ve seen detailed specifications long before they’ve been officially announced.

As the R1250GS title suggests, the capacity of the boxer twin is being increased. In fact, it’s rising by 84cc, from 1170cc in the current model to 1254cc next year. Along with those cubes comes a power hike from 123.3 to 134.1hp. That peak still comes at the same 7750rpm as on the current model, but will be backed up with a much stronger low-end performance thanks to a variable valve timing system, the first to appear on a BMW motorcycle, that will alter valve timing and overlap as revs rise to improve emissions and low-end torque without damaging peak performance.

While the engine is almost entirely new, it’s going to be bolted to an almost unchanged chassis, retaining most of the same dimensions as the current R1200GS models. At 86.9in, the 2019 R 1250 GS is exactly the same length as the existing R1200GS, while the R1250GS Adventure, at 89.4in, is 0.6in longer than its predecessor. Widths are unaltered at 35.2in for the GS and 38.6in for the GS Adventure, and wheelbases are also unchanged at 59in for the GS and 59.8in on the Adventure.

That other key figure, weight, is going to rise, thanks to the addition of the larger engine, its variable valve timing system and a new, quieter exhaust.

Both models gain 11lb, taking the R 1250 GS up from its predecessor’s 538lb curb weight to 549lb. The R1250GS Adventure is significantly heavier, thanks largely to a bigger fuel tank; around 7.9 gallons compared to 5.3 gallons on the GS. When filled-up and ready-to-ride, it’s going to come in at 591lb, up from 580lb for the current R1200GS Adventure.

All of BMW’s 2019 bikes – and there will be a total of nine new models, including the three mentioned here – are set to make their first public appearances at the Intermot show in Cologne in the first week of October. Other new BMWs at the event will include a completely redesigned S1000RR superbike, a new C 400 GT scooter and a new R1250RT equipped with the same 134hp VVT engine as the new R1250GS.