science

Xtracycle

Xtracycle is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Xtracycle rather than just read about it. In short: Xtracycle is the name of a company and the name commonly used for the variety of load-carrying bicycle that results from use of the company's products: the FreeRadical kit. Web forums and blogs often use the shorthand Xtrabike, Xtra, or simply X to refer to either the FreeRadical extension or the entire extended bicycle.

Key takeaways

Xtracycle belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Xtracycle to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Xtracycle from memory before moving on to harder problems.

Reference excerpt

Xtracycle is the name of a company and the name commonly used for the variety of load-carrying bicycle that results from use of the company's products: the FreeRadical kit. Web forums and blogs often use the shorthand Xtrabike, Xtra, or simply X to refer to either the FreeRadical extension or the entire extended bicycle.

History and spin-offs The FreeRadical was conceived by Ross Evans at Stanford University and developed during his work in the mid-1990s managing a "Bikes Not Bombs" project in Nicaragua, where having a bicycle enhances a person's employment opportunities. In 1998 Evans and his friend Kipchoge Spencer created Xtracycle Inc to manufacture and market the invention, as well as a nonprofit organization, Worldbike, devoted to encourage a bicycle-centric lifestyle and culture. Despite the fact that the FreeRadical qualifies as an aftermarket bike accessory, its growing acceptance has sparked an Xtracycle aftermarket not formally connected with Xtracycle Inc: varieties of specialized kickstands, electric-assist motors Archived 2017-11-19 at the Wayback Machine, and even bike-mounted blenders have come to market, even though each requires the prior purchase of a FreeRadical or other Xtracycle-compatible frame to function properly.

Big Dummy

Xtracycle Inc has worked with various bicycle manufacturers to build purpose-built extended bicycles compatible with their accessories. The first to actually produce and market an integrated Xtracycle frameset was Surly Bikes with the Big Dummy. XInc continues to form similar covenants with manufacturers in all price ranges, with the goal of making the Xtracycle less of a niche product and more mainstream. XInc is also working on FreeRadical attachments sized for children's and youths' bicycles. Other applications for the FreeRadical have included linking two Xtracycles to support a mobile stage for use in parades and street fairs, and a computerized chalkpowder-printer device mounted on an Xtracycle that leaves a dot-matrix trail of messages on the street.

Open source In 2008, Xtracycle put their longtail bike frame specifications online as part of their project to open source their longtail frame design. They’ve created a Longtail Standard and logos to allow vendors to design their products to fit in the Xtracycle FreeRadical ecosystem. The "Longtail Technology" logo can be used on bikes, accessories or packaging. The open sourcing of the patented technology was meant to stimulate the cargo bike movement, while developing a standard for "longtail" frames and accessories. Several frame and accessory makers have adopted the standards, while others have developed competing and incompatible long-frame cargo bike designs. However, the documents are no longer freely available, and now require an agreement with Xtracycle first.

Products

FreeRadical

The FreeRadical is an extender for a bicycle.

Radish In 2009 the Radish was launched by Xtracycle. It is a production long-tail bicycle with a low-standover height frame and matching FreeRadical.

EdgeRunner In 2013 the EdgeRunner is a second generation cargo bicycle with a 20-inch rear wheel. The EdgeRunner has been called the "Best longtail ever. No contest."

CargoJoe In 2013 the CargoJoe is a folding cargo bike developed in a partnership between Xtracycle and Tern.

Sidecar In 2011 Xtracycle created a sidecar for cargo transport that can carry up to 250 pounds.

See also Bicycle luggage carrier Electric bicycle Cargo bike Outline of cycling Modular design Open-hardware vehicle

References

External links Official site links to cargo-carrying bikes Bike Hugger Bettie, a Sport Utility Bike project using the Xtracycle Surly's page describing the Big Dummy frameset Xtracycle Gallery—Gallery of Xtracycle pictures

Illustrations

Worked examples

Example 1 — a first encounter with Xtracycle

Start with the simplest possible case. Write down what Xtracycle claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Xtracycle before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Xtracycle ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Xtracycle

In research: Xtracycle appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Xtracycle in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Xtracycle is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cycle types, Modular design, so understanding it makes those chapters shorter.
In everyday life: Look for Xtracycle outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Xtracycle” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Xtracycle in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Xtracycle means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Xtracycle out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Xtracycle in simple terms?

Why does Xtracycle matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Xtracycle?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Xtracycle.