Chapter 175

**Ultra Race Across South America** (南 (なん) 米 (べい) 横 (おう) 断 (だん) ウルトラレース, *Nanbeiōdan Urutorarēsu*) is the one hundred seventy fifth chapter of the *Dr. Stone* manga.

## Summary

The chapter starts with Kaseki and Chrome stretching a piece of rubber, only for it to snap back and smack Chrome, who is delighted. Kohaku is then shown expertly dribbling and juggling the rubber balls they made last chapter, to the awe of Chelsea and Luna. She brings up the fact that as it is, it's too floppy to be of any use for anything but a plaything. Senku explains that there's a next step to be done, to which Xeno adds that until the next step was discovered 200 years after Columbus brought it back to Europe, rubber was not used for any preactical purpose.

Senku then asks Taiju to help with the processing: roll the rubber into sulphur and carbon powder, turning it black, then heating and stretching it (vulcanisation). Finally, Senku stamps the tire pattern onto it.

Xeno then asks if they'll be making inner tubes separately, leading Kohaku to question why he's being so helpful. Xeno responds that he's doing it with his own well-being in mind, saying the "Junior Science Brigade" is free to do whatever they want as long as they're not taking Xeno down with them, then adding they should be fine with Senku at the helm.

Senku then continues with his scientific explanation, shaping the rubber into circles and tossing in wires and cloth. Heating then cooling gives it the tire shape, then Taiju helps him to put in the rubber inner tubes and wheel axles. Finally, they just need to inflate the inner tube then they have tires. Kohaku comments that they're much smoother and speedier than the old bamboo wheels. Chrome is shown being flung off the ship a second time by the rubber.

Senku and Ryusui then direct everyone to start making the vehicles as fast as possible, as they're on a tight schedule, to which Gen complains they're *always* on a tight schedule. Kaseki starts ripping apart the boat to work on the vehicles (his favourite modern craft).

We then go back to Stanley on the Perseus, chasing the decoy Mobile Lab. As soon as they have visual, Stanley states it's a decoy and destroys it using the battle station, sinking the poor mobile lab. Stanley then confirms there's no one on board before commanding them to back up and chase the other boat southward.

Chelsea announces they've reach Ecuador, which is now a dry desert. Hyoga comments that the journey should be easier but there won't be much cover. Him and Kaseki then starts ripping apart the boat they no longer need to repurpose it for motorbikes. Carlos and Gen are shocked when Ryusui says the motorcycles with run on wood, with Xeno correcting that it'll be the gas produced from burning wood.

Senku tells everyone he'll be making one 'boss' bike and five 'baby' bikes, where the 'boss' one has a boiler for burning wood and collecting charcoal gas, then the baby ones use the six engines from the boat fuelled with the collected gas.

Ukyo informs everyone that the mobile lab has been sunk, and Stanley is coming for them. Ryusui tells everyone to strap in for several all-nighters of hard labour.

Some time later, the Perseus appears at the shore, Suika standing on the remnants of their smaller boat to alert them. Stanley and his team jump off using ropes, yelling to surround them. Ginro calls from inside the Perseus to run.

Lights flick on.

Something cracks and breaks.

A motorcycle, driven by Gen with Senku riding passenger breaks out of the wall.

The team rides off together, with Xeno gagged.

## Chapter Notes

* Vulcanised rubber, tires and motorcycles are acquired.
* The mobile lab is destroyed.
* The teams reach Ecuador.
* The stolen boat is reused to make motorcycles.
* The groups on the motorcycles are as follows:
	+ Gen (driver), Chelsea, Senku
	+ Ukyo (driver), Suika, Kohaku
	+ Taiju (driver), Kaseki
	+ On the largest motorcycle: Ryusui (driver), Xeno (gagged), Hyoga
	+ The remaining people are: Chrome, Francois, Tsukasa, Carlos, Max, and Luna on the other two motorcycles.

## Characters in Order of Appearance

* Senku Ishigami
* Kaseki
* Gen Asagiri
* Chrome
* Kohaku
* Chelsea Childe
* Luna Wright
* Xeno Houston Wingfield
* Taiju Oki
* Ryusui Nanami
* Carlos Barrios
* Max Adams
* Suika
* Stanley Snyder
* Maya Biggs
* Tsukasa Shishio
* Hyoga
* Ukyo Saionji
* Ginro

## Trivia

* The motorcycles and desert chase designs were inspired by Mad Max and Akira.
* The mobile lab is shown with a tiny halo as it sinks on the map on page 9.
* Stanley never confirms the state of the Panama Canal.
* The Atacama desert has spilled over from Peru all the way to the coast, making it an arid region. Chelsea would have expected a humid, subtropical climate if it were still the 21st century.