Jeep’s upcoming Wrangler-based pickup truck has been spotted testing once again, and it looks like the engineers are still working out which tires to use. 

The prototypes seen here are wearing two different sets of tires: some beat up looking Goodyear Wranglers and Falken Wildpeak A/Ts. It could be that Jeep is still trying to decide on which tire to offer as stock equipment, though it is also possible that a more aggressive trim could be offered with the Falkens, while the Wranglers could be the base tire.

Besides the new rubber, we can also see clearly that these trucks are all four-door Unlimited models, which, so far, has been the only body style we have seen in spy shots of the new truck. A standard two-door model is certainly possible, but so far it hasn’t been seen testing. A Chevy Silverado also shows up in one of the photos, showing that Jeep is even benchmarking half-tons for its new midsize pickup.

READ MORE: 2018 Jeep Wrangler Caught on Video

With the all-new JL Wrangler expected to debut sometime before the end of 2017, the pickup won’t likely be shown until next year. Both will share the same frame and benefit from efforts to cut weight by using aluminum and plastic body panels.

Under the hood, the 3.6-liter Pentastar V6 will almost certainly be an option, hooked to either a manual or an eight-speed automatic, while a smaller 2.0-liter turbo is also expected to show up. The availability of the 3.0-liter EcoDiesel engine, which has been rumored to be coming in the JL for some time, remains to be seen considering FCA’s current battle with the Environmental Protection Agency and the California Air Resources Board over diesel emissions.

We should learn more about the pickup when the standard Wrangler debuts, but we won’t know everything about this new Chevy Colorado and Toyota Tacoma competitor until at least 2018.