Does FlexSeal® work on bike tires? (We tried it)


Flex Seal® is a range of adhesive products made by the Swift Response company situated in Weston, Florida. The brand is well known in America particularly as they have used television advertisements to develop awareness. They make some strong claims about the effectiveness of their products, most of which have been verified through independent testing.

The question of whether flex seal®  works on bicycle tires needs to be qualified. The FlexSeal product is a sealing agent contained in a high-pressure spray can. Containing a solvent means that it will further damage the tire. The FlexTape® product will work for temporary repairs.

When you need to fix a punctured bike tire, and you don’t have the proper repair lit, FlexTape® is an interesting solution. The opposite is true for Flex Seal®, the manufacturer advises that it is not compatible with many rubbers.

Flex Seal® Does Not Work On Bike Tires

The Flex Seal® brand consists of a range of eight products, as follows.

  1. FlexPaste®
  2. FlexSeal®
  3. FlexSeal Colors®
  4. FlexSeal Liquid®
  5. FlexTape®
  6. FlexShot®
  7. FlexGlue®
  8. FlexSeal Adhesive Remover®

The only two products which we are going to discuss in this article are Flex Seal® and Flex Tape®.

Flex Seal® Is An Adhesive Contained In A High Pressure Spray Can

Flex Seal is a multi-purpose liquid rubber spray which an elastomer that cures outside of the can, but not inside it. 

According to the manufactures web site it can be used to

  1. Roof and gutter repair
  2. Weatherize your home
  3. Foundation and concrete waterproofing
  4. Indoor and outdoor projects
  5. Seal cracks and holes
  6. Pools and pool equipment
  7. RV and motorhome repairs
  8. Auto and boat repairs
  9. Bathroom fixes
  10. Furniture repairs

The manufacturer claims that Flex Seal® works on Wood, metal, tile, concrete, masonry, fabric, glass, plastic, aluminium, porcelain, dry wall, rubber, cement, some vinyl’s.

It is applied  by simply spraying the product on the area to be sealed, wait 24 hours, and then apply a second coat.

There are five reasons why you cannot use FlexSeal® to repair a bicycle tire

  1. Flex Seal® is designed to withstand hydrostatic (unpressurised water) pressure but is not designed to withstand very high pressures, whether these be from fluids or gasses.
  2. Flex Seal®  takes 24 hours to cure.
  3. Flex Seal®  spray contains TolueneOpens in a new tab., which  effectively breaks down the surface of the rubber sheet compound and makes it extremely sticky. It is a solvent which does not adhere to silicone or rubber.
  4. The manufacturer specifically states that it cannot be used to fix tire punctures. 

Applying the product to a leaking tire resulted in a steady stream of bubbles from the puncture, with no seal taking place.

Flex Tape® Does Work On Bicycle Tires

FlexTape® is a multi-layered adhesive which is applied on a thick, flexible rubberized backing that can be shaped onto many different shaped surfaces. In television advertisements the manufacturer claims it can be applied underwater and to virtually any surface. This has been independently tested and verified.

The manufacturer claims it can be used in the following applications.

  1. Plumbing repairs
  2. Seal out air and water
  3. General home repairs
  4. Fast fixes on boats, autos, or RVs
  5. Roof repairs
  6. Pool repairs
  7. Bath and shower repairs
  8. DIY projects

The manufacturer claims that FlexTape® works on the following materials: PVC, acrylic, metal, steel, copper, aluminium, wood, ceramic, porcelain, tile, glass, rubber, fiberglass, stucco, plaster, stone, cement, concrete, dry wall, EPDM roofs, some plastics, fabrics, vinyl and more.

Once the FlexTape® backing layer has been removed, FlexTape will adhere to Silicone and rubber. This makes it a potential candidate to carry with you as an emergency repair product. After the backing tape has been removed, the adhesives begin to cure, and it gets stronger over time and as the pressure is increased.

If you don’t have a conventional puncture repair kit on your bike or person, and someone happens to mention that they have a spare roll of FlexTape® in their bag.

  1. Go to them and apologise humbly for not being a good boy/girl scout and not being prepared  for an inevitable puncture and ask for a small a piece of their magical material.
  2. Turn the bike over and spin the wheel with great exuberance. This doesn’t serve any purpose but shows the onlookers that you are a sharp bicycle rider and you know what you are doing.
  3. Examine the tire, and if the damage can be easily scene, mark it with a piece of chalk (Oh wait you didn’t bring a repair kit) or some mud off the side of the road.
  4. Using a tire lever (didn’t bring that either?) or a flat head screwdriver, carefully remove the tire and its tube from the wheel.
  5. If you cant see the damaged area, hold the tube under a stream of water (if available), or get a friend to put water in a cup which you should than feed the tire through, and watch for bubbles to appear. Mark where they originated. If there is no water available, hold the suspected damaged area next to your cheek and feel for the escaping air.
  6. Once you identify where the hole is, mark the damaged area (with the mud again).
  7. Clean the damaged area as well as you can.
  8. Cut a three-inch piece of FlexTape and remove the backing tape.
  9. Stick it over the hole making sure that the centre of the hole is in the middle of the applied FlexTape®.
  10. Wrap the FlexTape® completely around the tube, rubbing out any kinks or creases which have appeared.
  11. Put the tube back in the tire and the tire back on the rim. 
  12. Add air to the tube using the pump.
  13. Reinstall the wheel.

Although the product pack states that the FlexTape can be used for long lasting fixes and can withstands some pressure, the manufacturer states “Flex Tape® isn’t designed to be used for high pressure applications but It can be used to repair a bicycle tire inner tube in an emergency.”

Our experience is that it is very much a temporary fix and, although it will be good to get you back to safety, the puncture should be permanently fixed as soon as to return to the safety of the base.

Conclusion

Flex Tape® has enjoyed a degree of notoriety mainly due to the manufacturer’s television advertising. The spots make extravagant claims regarding the products efficacy, most of which has been backed up by independent testers.

The manufacturer claims that Flex Tape® can be used for emergency bicycle tire repairs, and although we agree we strongly advise that this is a temporary fix and once the bicycle has returned to base, the tire should be fixed with products designed for that purpose.

Although we would do not recommend that Flex Tape® be used instead of conventional tire repair kits, if there is nothing else available it will suffice.

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