Stayfill® keeps your wheels ready to roll


General FAQ


What is Stayfill®?

Stayfill® is a proprietary gas blend that keeps tires inflated for over a year. The actual gas mixture is a trade secret, but we can tell you that Stayfill’s molecules are 2-3 times larger than CO2 or air molecules. Stayfill’s larger molecules do not pass through tire walls like CO2 or air molecules. A Stayfill® cartridge is filled to approximately 320 psi @ 70℃. This compares to a CO2 cartridge, which is filled closer to 830 psi @ 70℃.

Why should I use Stayfill®?

Stayfill® makes sure your tires are ready to go when you are. No more pumping tires when you or your kids want to go on a bike ride or use equipment or tow a trailer. Stayfill® eliminates the hassle and frustration of pumping tires and offers the convenience of ready-to-go tires.

Can Stayfill® be used with CO2 or air?

Stayfill® can be used with CO2 or air. However, concentrations in excess of 14 psig may result in some CO2 or air leaking out thereby requiring a top off with Stayfill®.

Is Stayfill® safe to use?

Stayfill® is non-toxic, non-flammable, and non-ozone depleting. However, Stayfill® is packaged under pressure (approximately 320 psi @ 70℃) and can be dangerous if not handled properly.

Can I take Stayfill® on airplanes?

As of this writing, traveling by commercial aircraft with Stayfill® cartridges is NOT acceptable according to the United States Transportation Security Administration (TSA) website ( Before traveling with Stayfill® cartridges, it is strongly advised that you consult your local airline, airport and/or travel agent, and check the TSA website for any changes that may have occurred since this writing.

Will Stayfill® damage my tires?

Stayfill® is inert and will not harm your tires, ever.

How does temperature affect Stayfill® in my tires?

Stayfill®, like all gases, changes its pressure with changes in temperature. When temperatures drop, the pressure will drop. This means you may have to top off your tires with more Stayfill® when outside temperatures drop. Conversely, if you top off or fill your tires when it is cold, you may have to let some Stayfill® out of the tires when it gets warm again to get back to the optimum pressure. A Stayfill® cartridge is filled to approximately 320 psi @ 70℃. This compares to a CO2 cartridge, which is filled closer to 830 psig @ 70℃.

How will Stayfill® perform in latex based tires?

Great. Stayfill® will stay where it is supposed to — in your tires. The thinner latex tire walls are perfect for Stayfill®. While tires filled with CO2 or air will see extremely high leak rates, Stayfill® will not pass through the latex tire walls.

How much extra weight will Stayfill® add to my bike?

Stayfill® is heavier than CO2 or air but the actual amount will depend on the size of the tube and fill pressures. In our tests using high-pressure road tires, Stayfill® added approximately 3 ounces more than CO2 when filling both tires. For the weight conscious, this may be unacceptable, but for most of us, Stayfill® weighs less than one of those energy bars you might take on a ride.

How else can Stayfill® be used?

Stayfill® can be used in basketballs, footballs, soccer balls, inflatable pool toys, baby joggers, bicycle air struts, wheelchairs, ATVs, and more. Please write us and let us know about other uses for Stayfill®. We’d love to hear about it.

Canceling Your Order

To cancel your order you must send an email to within 8 hours of when you first placed your order or call 415-856-0570. If your order has been already processed we are not responsible for the shipping costs incurred.

Email cancellations must contain the following: First name, last name, order number, and email address. This information must be identical to the information originally submitted on your order. Please provide contact information so that we may contact you if we have questions in regards to canceling your order.

Every effort will be made to accommodate the cancellation of your order, providing your order has not been charged and/or shipped out. In the event that a cancellation was submitted (via email or phone), and your order was shipped out after, we will gladly refund the complete balance charged including shipping. However, if the cancellation was documented as received after the order was shipped, we will refund the merchandise total less shipping.

Shipping Charges

See bottom of page for a schedule of Shipping Charges.  Note, also, due to the hazardous nature of the Stayfill® product (as determined by the United States Department of Transportation 49 CFR), orders are only shipped within the continental United States by UPS Ground or FedEx Ground.  If expedited or international services (involving air freight and payment/collection of import duties) are required, please contact Stayfill® directly either at or at 415-856-0570.

Special Orders

Special orders will be at the discretion of Stayfill®, so please contact us either at or call 415-856-0570.

Sales Tax

Sales tax is charged on all products and orders shipping within California. Actual tax amount is applied at the state level when placing your order, and may vary depending on the county your product is shipping to.

Return Policy

In order to return an item, you must obtain a Return Number. Email us at sales@stayfill.comto obtain a return number. You may return any unopened merchandise in its original condition, including original packaging within 30 days of receipt and you will receive a full refund, less shipping. Any shipping cost that you incur to return a product to us will not be refunded.
We require the following information to process your return:

Note: Your return will not be processed if you do not provide ALL required information.

  • The Return number
  • Your full name and address
  • Phone number
  • Email address
  • Packing Slip
  • The original order confirmation number
  • The reason for returning the merchandise

Return address:
Attn: Returns
490 Post St., Suite 1700
San Francisco, CA 94102

Any package that has not been received by and tracking information cannot be provided, will be the sole responsibility of the shipper.

Orders Not Received

Once an order has been shipped and there is a delivery confirmation, Stayfill® is not responsible for any theft of product or delivery to the wrong address. You must notify us within 15 days if order is not received.

Out of Stock Items

From time to time, if we are not able to fulfill your order, you will be notified via email for any item that is temporarily out of stock or simply cannot be fulfilled. An immediate credit will be issued to your credit card or any other method of payment that you choose.

Shipping Policy

All orders are shipped, on average, within 48-72 hours from the time your order is placed. On average you should expect to receive your order within 5-10 business days from the time that you place your order.

Shipping Description
(Before Sales Tax for CA Residents)


Under $10 total purchase $0.00 – $10.00 $5.00
Under $30 total purchase $10.01 – $30.00 $10.00
Under $50 total purchase $30.01 – $50.00 $12.50
Under $75 total purchase $50.01 – $75.00 $17.50
Under $100 total purchase $75.01 – $100.00 $20.00
For orders over $100, contact Stayfill®


MSDS Sheet (pdf)