Sir Isaac Newton did not travel to Egypt. Nathaniel Davison and Giovanni Caviglia made an investigation at a different site.

Howard Vyse and Hill were the first ones to discover and clean the shafts, and they can be considered as candidates. However, as Howard Vyse was interested in the central part of the pyramid, and his way of investigation was rough that he was even using dynamite, it is doubtful if he would employ such a laborious method as making a four-wheeled vehicle. I assume that he probably cleaned the shafts in a simpler way such as bringing some kind of handy tool and poking the hole with it. In addition, as far as I know, Vyse did not even mention anything about the four-wheeled vehicle in his book.

Piazzi Smyth should also be regarded as a candidate as he took measurements of every part inside the Great Pyramid by using a special investigative implement. However, in a book written about him, there was no report on the four-wheeled vehicle.

Waynman Dixon and Bill Grundy seemed have been interested in the lower shafts coming form the Queen's Chamber rather than in the upper shafts from the King's Chamber. Thus, it was not them who made the vehicle.

Flinders Petrie also took accurate measurements of the Great Pyramid and visited the Mankiller tunnel as well. But, as he said in his report that he has used a rod, he is not the one either.

Such being the case, it is still unidentified who really has left the four-wheeled vehicle. I have already mentioned this, but Gantenbrink considers that this vehicle was used to clear the shaft that has been clogged with dust. He also cleaned the shaft himself, but it seems that he found a car axle, which would fit perfectly in the shaft, and then pushed it down to remove dust. Cleaning the shaft by taking measurements first and making a vehicle with four wheels by using an axle based on the measurements must be unreasonably time-consuming and costly if it is only for the purpose of "cleaning the shaft once." Moreover, as the interior condition is still unknown, the shaft might be getting narrower suddenly after a meter. Thus, "making a vehicle for cleaning purpose" is extremely risky. The way Gantenbrink cleaned the shaft was a lot simpler and natural.

Just as Gantenbrink argues, this four-wheeled vehicle might have been made quite recently. Yet, even if his intuition is right, I still feel that he should not reach the conclusion only with intuition but to investigate the measurements, weights, the quality of the materials, and structure to specify who has really made it. It is because that every one of the scientific investigations will be instrumental in explaining the significance of pyramid. However, because he is a discoverer and not an owner of the vehicle, he probably is not allowed to make further investigation. This might be the reason why he took offense when I threw out a question.

Reference:
The report on the "four-wheeled vehicle" can be found in THE SECOND 1992 CAMPAIGN of his website. Click the address below. The fourth picture is the image of the four-wheeled vehicle.

http://www.cheops.org/startpage/theupuautstory/thesecond1992campaign/second92.htm

Here is the website of Rudolf Gantenbrink. You can go into the site simply by clicking the "ENTER" written on a stone-button down the screen. Then choose CYBER DRAWING, and click OK button for downloading. In a little while after clicking CHEOPS SHAFTS or other item, you will receive the drawing. You can try conducting the buttons on the top several times at first, and learn the operational procedure of the drawing.
http://www.cheops.org/

Translated by Maiko Noda