Inner Tube Repair
Typical Tools and Supplies Needed
Pre-glued Patch Kit such as the GP-2
or Vulcanizing Patch Kit VP-1
- Pump: either floor or hand pumps. An air compressor with correct fittings can also be used.
- Useful items- marking pen, rags, alcohol solvent
This article will discuss the patching of bicycle inner tubes. Both the pre-glued patches and the vulcanizing patches will be reviewed. See also related articles: Wheel Removal and Installation and Tire and Tube Removal.
The GP-2 Super Patch Kit uses pre-glue patches. There is no tube of glue to leak or dry up.
To fix a flat, first locate the hole in the inner tube. If possible, re-inflate inner tube to at least twice the normal width. Inspect for air leaks by holding tube close to the sensitive skin of lips or by holding tube near your ear to hear leaks. Move the tube around its circumference. If you find one hole, keep looking for more. Inspect inside the tire for sharp objects or glass. Also inspect the rim strip in the rim. It should not have any holes around the spoke holes and should fully cover the holes.
If you plan to repair the inner tube, use a marking pen to mark hole. Make four marks, one to each side of hole. Do not mark close to hole, as the mark may be sanded off.
To Patch an Inner Tube Using the GP-2 Super Patch
Locate hole marked during inspection. Using fine emery cloth or sandpaper, clean the tube by lightly abrading area around hole. Excessive sanding or heavy pressure can cause grooves in the rubber, which may lead to patch failure.
- If available, wipe the area with clean rag and alcohol. Allow it to dry completely.
- Peel patch from patch backing. Handle patch as little as possible and by edges only.
- Center patch to hole and lay patch on tube.
Apply pressure to patch to assure seal. Roll patch and tube between thumbs and forefingers.
- Tube is ready to install. DO NOT test patch by inflating tube while outside of mounted tire. This may stretch tube body and weaken patch bond.
Patching an Inner Tube Using the VP-1 Vulcanizing Patch Kit
Glue type patches require the application of a thin layer of self-vulcanizing glue on the tube before the patch is applied.
Locate hole marked during inspection, as described above.
- Using fine emery cloth or sandpaper, lightly abrade area around hole. Abrade an area larger than patch size.
- When possible, clean area with alcohol and allow it to dry completely.
Open glue tube and puncture seal. Apply thin coat of glue and spread evenly around hole area. Spread area of glue larger than patch size. Use a clean finger or back of patch to spread glue evenly in a thin layer. Do not apply too much glue. Glue layer should not appear "glopped" on.
- Allow glue to dry. This may take several minutes. Test by touching only perimeter area of glue, not where patch will contact.
- Peel patch from patch backing. Handle patch only by edges.
Center patch to hole and lay patch on tube.
- Apply pressure to patch, especially at edges.
- If possible, maintain pressure for several minutes.
- Leave clear plastic cover on patch, do not peel up.
- Mount tube inside tire and inflate.
Temporary Repair of Tire with Tire Boot TB-1
If the tire has been ripped and the casing damaged, it may not hold an inner tube. It is possible in some cases to make a temporary repair with a Tire Boot. A booted tire should not be considered a permanent repair. The tire should be replaced as soon as possible.
- Locate rip in tire. Compare rip to size of tire boot. Tire boot must completely overlap rip to be effective.
- Wipe clean inside of tire adjacent to rip.
- If using Park Tool Boot TB-1, peel off backing of TB-1.
- Align patch so edges do not extend beyond tire bead. If necessary, cut boot so it does not extend past tire bead.
Center patch to rip and press patch to inside of casing.