Leon finished the new bicycle frame, its oval tubes inscribed with the anti-gravity rune array he'd redesigned.
"Inscribed" was a generous term. The array was little more than a decorative pattern—his mana wasn't strong enough to activate it, no matter how much he simplified the runes. He'd known that from the start, but he'd carved it anyway, then filled the grooves with silver wire to make it look more elegant.
Money made such luxuries possible. Once, he would have used copper or tin; now, silver felt trivial, a small indulgence after the Mana Stone mine's haul.
He'd nearly forgotten his original reason for visiting Im—asking about rubber substitutes—until he spotted the unfinished wheel rims on his workbench. The frame's redesign and rune experiments had eaten up three days, time he'd meant to spend on tires.
He found Im in the magic botanical garden, tending to the fire-element herbs in the warmest rune array zone. The air smelled of dry earth and smoldering wood, the temperature noticeably higher than the rest of the valley.
"Teacher, about that elastic, durable material," Leon said, interrupting Im's work. "Animal tendons won't work—they're not wear-resistant enough, and I'd need too many."
Im didn't look up, his fingers brushing a flamebloom's petals. "You want it for the wheel surfaces, not the axles." It was a statement, not a question.
Leon nodded. "To soften the ride. The roads are too bumpy for iron wheels." He'd dreamed of riding to Acorn Village, but iron rims would rattle his bones and slip on gravel. Solid tires were his backup plan—no inflation needed, just a thick, resilient layer.
"Eucommia gum," Im said, finally glancing at him. "I read a paper once. Dilute Amphora Extractor No.7 by 1,500 times, soak eucommia bark in it, and you can extract a rubber-like resin."
Amphora Extractors were the gold standard for mages—versatile solvents invented by the Amphora Mage Collective, capable of extracting compounds from plants, animals, and even metals. Their Extract No.11 could separate liquids by density, earning the collective a fortune and the title "Masters of Extraction."
"Where do I get the extract?" Leon asked. "And eucommia bark—I've seen a few trees, but not enough."
"There's a grove on the way to the Crosscut Mountains," Im said, returning to the flameblooms. "Hundreds of trees, enough for your needs. But finish the bicycle first with a temporary solution. Extracting usable gum will take weeks."
Leon agreed. Even if he found the extract and bark, refining the gum would be a lengthy process. A solid tire—crude but functional—would let him test the bicycle while he worked on the real thing.
He returned to his workshop, focusing on the wheels. They needed to be wide—wider than his old-world bicycle—to grip dirt roads and avoid sinking into mud. Wide wheels meant more work, though: thin, uniform spokes that were both strong and light, and a perfectly round rim.
The frame alone weighed nearly 30 kilograms, far heavier than he'd planned. He'd overcompensated with the steel tubes, worried about durability. Without Im's anti-gravity enchantment (which the mage refused to cast, calling it "coddling"), the bicycle would be too heavy for a 13-year-old to ride—even with Etho's physically robust humans.
The spokes were tedious but straightforward. He forged thin steel rods, cut them to identical lengths, and attached them to the hubs and rims. The real challenge was the bearings.
Leon needed perfectly round, hard, corrosion-resistant steel balls. His first attempts—mixing iron with other metals, carburizing the steel—failed miserably. He was a programmer in his past life, not a materials scientist; smelting steel was already pushing his limits, thanks to mage tutorials and old-world documentaries.
He reluctantly asked Im for help. The mage handed him a small ingot of chromesilver—a silvery metal harder than steel but far cheaper than mithril. "Mix it with your steel, carburize it," Im said. "It will hold its shape and resist rust."
Mithril was prized for its mana conductivity and strength, but chromesilver was a practical alternative for non-magical components. Leon melted the chromesilver with steel, carburized the alloy (a trick he'd learned from a documentary about sword-making), then forged, ground, quenched, and polished the metal into tiny, perfect balls.
With the bearings done, he attached the spokes to the hubs and rims, leaving a groove around the rim's edge for future tires. He lined the groove with cork to protect it from damage while he worked on the gum.
Magic made the process faster—Mage Hand held spokes steady, small fire spells heated metal—but it was still labor-intensive. Leon marveled at how Etho's mages prioritized magic over precision crafting; without his old-world knowledge, he'd never have made bearings this precise.
By evening, the bicycle was assembled: a heavy chrome-steel frame with silver-inlaid runes, wide cork-lined wheels, a leather seat, and wooden handlebars. Leon pushed it across the workshop floor, testing the bearings. They spun smoothly, the anti-gravity runes glinting uselessly in the firelight.
He hid the bicycle in the cottage's storage room. He wanted to show it off in the morning, when the sun was bright enough to make the polished metal shine.