Which Tire Sealant Brand Wins?
This head-to-head test of 4 tire sealant options has the measured results for each. See how they ranked and watch the full test video.
MultiSeal
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The measured results
Every number below is read straight from the test. Products are listed in the order they finished.
Contents/SDS
- 1MultiSeal
not much information available, contains propylene glycol; gooier and thicker with larger particles than Tire Slime, forms a glue like consistency
- 2Tire Slime
glycerol, attapulgite, cellulose, and quartz; small black particles visible, thick and pasty
- 3TireJect
propylene glycol and natural rubber latex (an allergy consideration); no particles seen but some globs, becomes glue like very quickly
- 4Fix-a-Flat
tetrafluoropropene, glycerol, and cellulose; no visible particles, host was unsure how the product mechanically seals a hole
Initial small puncture test
- 1MultiSeal
sealed the drywall-screw sized hole, no leak seen, held 30 lbs of pressure after about 15 hours
- 2Tire Slime
sealed the drywall-screw sized hole, no leak seen, held 30 lbs of pressure after about 15 hours
- 3TireJect
sealed the drywall-screw sized hole, no leak seen, held 30 lbs of pressure after about 15 hours
- 4Fix-a-Flat
failed, continued leaking significantly; a second can was applied and still failed; lost pressure from 30 lbs down to about 4 lbs overnight
Freeze test (-15F for 24 hours)
- 1MultiSeal
did not freeze, still a gel, ranked best of the 4, described as very impressive
- 2Tire Slime
ranked third of the 4, still seemed like it would work but not as good a gel as MultiSeal or TireJect
- 3TireJect
ranked second of the 4, still in a gel like state
- 4Fix-a-Flat
ranked worst (fourth) of the 4, froze solid
Corrosion test (untreated steel, zinc washer, aluminum, 24 hours)
- 1MultiSeal
no visible rust on the zinc washer or aluminum; some color change on the untreated steel that the host could not confirm was rust or not
- 2Tire Slime
no visible rust, black specs described as normal for the product
- 3TireJect
showed surface oxidation and, after cleaning, some surface rust starting lower on the steel, the only product with a clearly stated rust result
- 4Fix-a-Flat
no visible rust
Cleanup ease
- 1MultiSeal
ranked easiest to clean up of the 4 products
- 2Tire Slime
ranked second easiest to clean up
- 3TireJect
ranked hardest to clean up of the 4 products, leaves a coating that will not come off with water and dries stringy
- 4Fix-a-Flat
ranked third easiest to clean up, described as not turning into as big a mess as some other products since it does not become slime
Application
- 1MultiSeal
required 32 oz for the full-size tire, more volume than the other products, but flowed a lot easier than Tire Slime
- 2Tire Slime
took the longest amount of time and the most effort of the 4 products to apply
- 3TireJect
close second easiest to apply behind Fix-a-Flat, small pouches empty out quickly
- 4Fix-a-Flat
ranked easiest of the 4 products to apply
Larger puncture test (1/4 in bolt)
- 1MultiSeal
sealed the enlarged hole, no leak after a 5 mile drive
- 2Tire Slime
sealed the enlarged hole, described as a very impressive performance after a 5 mile drive
- 3TireJect
sealed the original hole and continued to hold after the hole was enlarged and driven 5 miles
- 4Fix-a-Flatnot tested
All measurements (1 more)+
Severe puncture test (3/8 in landscape spike, tested only on this brand)
- 1MultiSeal
stopped the leak, tire held pressure, per the manufacturer's own claim of handling punctures up to 1/2 inch
- 2Tire Slimenot tested
- 3TireJectnot tested
- 4Fix-a-Flatnot tested
How it was tested
- initial small puncture seal test (drywall screw sized hole, pressure check after about 15 hours)
- off-road driving test (about 4 miles) since one product is off-road only
- corrosion test on untreated steel, a zinc coated washer, and aluminum over 24 hours
- freeze test at 15 degrees below zero Fahrenheit for 24 hours
- composition/particle test, straining each product to see what solids or particles are inside
- larger puncture test using a 1/4 inch bolt to enlarge the original hole, re-tested after a 5 mile drive
- severe puncture test using a 3/8 inch landscape spike, run only on MultiSeal per its own larger-puncture claim
- final teardown of each tire to inspect the sealant and repaired area inside
- cleanup ease and application ease comparison, plus price
“So, is Tire Slime the best? In my opinion, it is the best for on-road purposes. However, MultiSeal seems like it's an overall better product for off-road purposes.”
Data notes and caveats
This video ends with two separate per-use-case picks rather than one overall winner: Tire Slime is named best for on-road use, and MultiSeal is named the overall better product for off-road use, so winner and runnerUp are left null per the per-use-case convention and both picks are preserved in the corresponding products' notes. TireJect is praised as working fairly well but is not named the top pick in either category. Fix-a-Flat is the clear last place finisher, failing its very first small puncture test across 4 separate cans and therefore excluded from the later larger and severe puncture tests. MultiSeal and TireJect prices are never stated as exact figures, only described as 'quite a bit more expensive' than Tire Slime ($8.99) and Fix-a-Flat ($6.83); recorded as null per the never-invent-a-price rule rather than estimated. The severe puncture (3/8 inch landscape spike) test is explicitly run only on MultiSeal because it is the only product to claim it can handle punctures up to 1/2 inch, a genuine test-design choice rather than a caption gap. Chapters align very precisely with the video's actual test sequence per brand and test type.
