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ប្រដាប់ដែលស្លៀក
Building a Safety Bicycle — Chain Drive, Equal Wheels, and Personal Freedom
Palpatine

បង្កើតដោយ

Palpatine

25. មិថុនា 2026US
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Building a Safety Bicycle — Chain Drive, Equal Wheels, and Personal Freedom

The bicycle that everyone rides today was settled in the 1880s and is still called, in the trade, the safety bicycle — to distinguish it from the terrifying high penny-farthing it replaced. Two equal wheels, a diamond frame, a chain driving the rear wheel, and soon air-filled tyres made cycling safe, fast, and available to ordinary people.

Each feature solves a problem. Equal wheels and a low frame mean you can put a foot down and cannot be pitched over the handlebars. The chain and gearing let a small wheel travel fast without the giant front wheel of the penny-farthing. The diamond frame, built of brazed steel tubes, is astonishingly light and strong for its weight. And Dunlop's pneumatic rubber tyres turned a bone-shaking ride into a smooth one.

The safety bicycle was more than transport. Cheap, simple, and needing no horse or fuel, it gave working people and especially women a freedom of movement they had never had — which is why it is often credited with as much social change as mechanical.

មធ្យម
Several days for a full build

ការណែនាំ

1

Understand the safety design

The safety bicycle has two equal-sized wheels, a low diamond frame, and a chain driving the rear wheel. Together these let the rider reach the ground with a foot and avoid being thrown over the front — the dangers that made the tall penny-farthing so risky.
2

Braze the diamond frame

Cut steel tubes to length and braze them into the classic diamond: head tube, top tube, down tube, seat tube, and the rear triangle of seat-stays and chain-stays. Brazed thin-wall steel tube is light yet stiff, which is why the diamond frame has never been bettered for simple bicycles.

សម្ភារៈសម្រាប់ជំហាននេះ៖

បំពង់ដែករចនាសម្ព័ន្ធបំពង់ដែករចនាសម្ព័ន្ធ4 ម៉ែត្រ

ឧបករណ៍ដែលត្រូវការ៖

ដុំភ្លើងផ្សារស្ពាន់ដុំភ្លើងផ្សារស្ពាន់
3

Build the wheels

Lace steel spokes between a central hub and a steel rim, then tension them evenly so the wheel runs true. A tensioned wire-spoked wheel is extraordinarily light for the load it carries — the spokes work in tension, hanging the hub from the rim.

សម្ភារៈសម្រាប់ជំហាននេះ៖

ស្ពុកកង់ដែកស្ពុកកង់ដែក72 ដុំ
រង្វង់កង់ជិះ (អាលុយមីញ៉ូម)រង្វង់កង់ជិះ (អាលុយមីញ៉ូម)2 ដុំ

ឧបករណ៍ដែលត្រូវការ៖

កូនសោចម្រឹងកង់កូនសោចម្រឹងកង់
4

Fit pneumatic tyres

Mount air-filled rubber tyres on the rims. Dunlop's pneumatic tyre, made possible by vulcanised rubber, cushions the ride over rough roads and grips far better than the solid tyres it replaced — the single biggest comfort improvement of the era.

សម្ភារៈសម្រាប់ជំហាននេះ៖

កង់កៅស៊ូកង់កៅស៊ូ2 ដុំ
5

Build the chain drive

Fit a large chainwheel at the pedals and a smaller sprocket at the rear hub, joined by a roller chain. The ratio between them gears the bicycle so that equal-sized wheels can still travel fast for each turn of the pedals.

សម្ភារៈសម្រាប់ជំហាននេះ៖

ខ្សែច្រវាក់រ៉ូឡែខ្សែច្រវាក់រ៉ូឡែ1 ដុំ
កង់ច្រវ៉ាក់កង់ច្រវ៉ាក់1 ឈុត
កង់ខ្សែសង្វាក់កង់ខ្សែសង្វាក់1 ឈុត
6

Fit the bottom bracket and cranks

Mount the pedal axle in the bottom bracket on smooth bearings, then fit the cranks and pedals. Good bearings here turn the rider's effort into motion with little loss, so the bicycle rolls easily.

សម្ភារៈសម្រាប់ជំហាននេះ៖

រ៉ូលម៉ង់គ្រាប់រ៉ូលម៉ង់គ្រាប់1 ឈុត
7

Set up the steering

Fit the front fork through the head tube on headset bearings and clamp on the handlebars. The fork's slight forward rake gives the steering a self-centring trail that makes the bicycle want to balance itself once moving.

សម្ភារៈសម្រាប់ជំហាននេះ៖

ចង្កូតចង្កូត1 ដុំ
8

Fit brakes

Add brakes that press pads against the wheel rims, operated by levers on the handlebars. Reliable braking matters far more on the fast, low safety bicycle than it did on slower machines, so set them to grip firmly and evenly.

សម្ភារៈសម្រាប់ជំហាននេះ៖

ដង្កាប់ហ្វ្រាំងដង្កាប់ហ្វ្រាំង2 ដុំ
9

Fit the saddle

Mount a sprung leather saddle on a seatpost and set its height so the rider's leg is almost straight at the bottom of the pedal stroke. Correct saddle height is the difference between an efficient ride and a painful one.

សម្ភារៈសម្រាប់ជំហាននេះ៖

កែបស្បែកកែបស្បែក1 ដុំ
10

Assemble and true

Bring it all together: wheels in the frame, chain on, brakes and steering connected. True the wheels by adjusting spoke tension until they spin without wobble, and adjust every bearing so it turns freely but without play.

ឧបករណ៍ដែលត្រូវការ៖

សោរបំពង់សោរបំពង់
11

Test and tune

Ride gently at first, checking that the brakes bite, the steering is steady, and nothing rubs or rattles. Fine-tune the saddle, bars, and bearings. A well-set-up safety bicycle feels stable and almost steers itself at speed.

ឧបករណ៍ដែលត្រូវការ៖

សោរបំពង់សោរបំពង់
12

Appreciate the freedom it gave

Pedal away on a machine that needs no horse, no fuel, and no rails. Cheap and simple, the safety bicycle gave ordinary people — and famously women — independent mobility for the first time, reshaping society as much as it reshaped travel.

សម្ភារៈ

11

ឧបករណ៍ចាំបាច់

3

ប្លង់ពាក់ព័ន្ធ

ប្លង់ទាំងនេះចែករំលែកចំណេះដឹង — បច្ចេកទេស សម្ភារៈ ឬគោលការណ៍

Vulcanizing Rubber with Sulfur — The Accidental Discovery That Put Tyres on the Road

Vulcanizing Rubber with Sulfur — The Accidental Discovery That Put Tyres on the Road

ដោយ CharlieDE

ឧស្សាហកម្ម

81
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0
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3
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CC0 សាធារណៈ

ប្លង់នេះត្រូវបានចេញផ្សាយក្រោម CC0។ អ្នកមានសិទ្ធិចម្លង កែប្រែ ចែកចាយ និងប្រើប្រាស់ដោយមិនចាំបាច់សុំអនុញ្ញាត។

គាំទ្រអ្នកបង្កើតដោយទិញផលិតផលតាមរយៈប្លង់របស់ពួកគេ ដែលពួកគេទទួលបាន កម្រៃជើងសារអ្នកបង្កើត កំណត់ដោយអ្នកលក់ ឬបង្កើតកំណែថ្មីនៃប្លង់នេះ ហើយបញ្ចូលជាការតភ្ជាប់ក្នុងប្លង់របស់អ្នកដើម្បីចែករំលែកចំណូល។

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