Search for a motorcycle flat tire and the first page of results is unanimous: get a plug kit, push the plug in from the outside, inflate, ride on. Reddit is at the top asking whether anybody actually trusts it. YouTube shows you the technique. Four different shops sell you the tool.
Nobody in that first page makes tires.
So I went and read what the companies that build them actually publish. Dunlop’s technical Care and Maintenance document. Bridgestone’s Motorcycle Tire Safety and Maintenance Manual. Michelin’s repair guidance. The American federal standard that governs motorcycle tires, the British MOT inspection manual, the licensing manual that American riding tests are built on, and the owner’s manuals of two Yamahas built ten years apart.
They do not say what the first page of Google says. One of them says the exact opposite, in four words, on its own website — while a different page on the same website teaches you how to do it.
You will not hear it happen
Start with the part nobody writes about, because it is the only part that can hurt you: the moment the air leaves while you are still moving.
The MSF Motorcycle Operator Manual is the 18th-edition booklet that a large number of American states build their knowledge test on. Its section on tire failure opens with a sentence that should be better known than it is:
You will seldom hear a tire go flat. If the motorcycle starts handling differently, it may be a tire failure.
That is the whole warning system. No bang, no hiss, no light on the dash. The bike simply starts behaving like a different bike, and the manual then tells you what “different” feels like, front and rear, because they are two separate emergencies.
If the front tire goes flat, the steering will feel “heavy.” A front-wheel flat is particularly hazardous because it affects your steering. You have to steer well to keep your balance.
If the rear tire goes flat, the back of the motorcycle may jerk or sway from side to side.
Heavy steering in front. A tail that moves on its own behind. Those are the two symptoms, and they are the reason the same event has two different levels of seriousness — a fact worth carrying alongside everything else in the pre-ride checklist, which is where most riders would catch the nail before it becomes a moving problem.
The official procedure is three moves, and one of them is counterintuitive
Here is the manual’s actual instruction, in full:
If either tire goes flat while riding: Hold handgrips firmly, ease off the throttle, and keep a straight course.
If braking is required, gradually apply the brake of the tire that isn’t flat, if you are sure which one it is.
When the motorcycle slows, edge to the side of the road, squeeze the clutch and stop.
Read the middle line again. The advice is not “brake gently with both”. It is: brake on the good tire, and only if you are sure which one is flat. That runs against everything else riders are taught, because the whole of braking technique — the front does most of the work, use both, the ABS in the manual exists to let you squeeze harder — assumes two inflated tires. Take the air out of one and the arithmetic changes.
It is also worth noticing what makes the difference between reacting well and reacting badly here, and it is not skill: it is having decided in advance. That is the same argument behind riding defensively and behind knowing what a wet road does to your braking before you meet one, which is its own subject entirely.
I did not expect to find this on an exam paper, but it is on one. The manual’s sample knowledge test contains it as question 4:
If a tire goes flat while riding and you must stop, it is usually best to:
A. Relax on the handgrips.
B. Shift your weight toward the good tire.
C. Brake on the good tire and steer to the side of the road.
D. Use both brakes and stop quickly.
And the answer key on page 45 reads “Answers to Knowledge Test (p.44): 1-B, 2-C, 3-C, 4-C, 5-B”. The answer is C. Which means the other three options — relax your grip, shift your weight, use both brakes hard — are the three things the instinct reaches for, listed as wrong answers on a licensing exam.
There is something else about that booklet. In its 20,326 words there is no instruction anywhere on how to repair a tire. It teaches you to survive the deflation and stop. What happens next is somebody else’s document, and this is where it stops being simple.
Before you decide anything, read the sidewall
The single most useful thing on a motorcycle tire is a word, and it is there because a federal standard requires it.
FMVSS 119 — formally 49 CFR § 571.119 — is the American standard for new pneumatic tires for heavy vehicles, specialty tires and, explicitly, “tires for use on motorcycles manufactured after 1948”. Its section S6.5 lists the markings every covered tire must carry on its sidewall. Alongside the DOT symbol, the identification number, the size designation and the load range, there is item (g):
The words ”tubeless” or ”tube type” as applicable.
That word decides everything about your afternoon. A plug is a tubeless technique: it seals the hole in the carcass because on a tubeless tire the carcass is the air chamber. On a tube-type tire — most spoked wheels, most classic bikes, a lot of dual-sport machinery — the air lives inside a rubber tube, so the hole you can see in the tread is not the hole that is leaking. The tool in your tank bag cannot reach it. Dunlop’s consumer guidance says exactly that, in the plainest possible terms: for a tubed tire “you will need to remove the wheel”, patch the tube, refit.
Two more items from the same list are worth knowing, because they answer questions riders ask constantly. Item (d) requires the maximum load rating “and corresponding inflation pressure of the tire”, printed as “Max load ____kg (____lb) at ____kPa (____psi) cold” — which is why the number on the sidewall is a maximum for the tire, not the pressure for your bike. And item (e) requires “the speed restriction of the tire, if 90 km/h (55 mph) or less”. A tire with no speed marking is not a tire without limits; it is a tire above that threshold.
The standard even makes a special allowance for motorcycles on how the marking is applied: the letters can be shallower, at “not less than 0.25mm (0.010 inch)”, and “markings may appear on only one sidewall and the entire sidewall area may be used in the case of motorcycle tires”. If you cannot find the word on the side facing you, it is legitimately on the other one.
The standard has a puncture test, and the plunger is nail-sized
FMVSS 119 does not regulate repairs at all. In 3,302 words the word “repair” appears zero times, because the standard governs tires as they leave the factory. But it does contain a strength test, and the strength test is a controlled puncture.
Section S7.3 describes it:
Force a cylindrical steel plunger, with a hemispherical end and of the diameter specified in Table I for the tire size, perpendicularly into a raised tread element as near as possible to the centerline of the tread, at a rate of 50 mm (2 inches) per minute…
Table I gives the plunger diameter by tire type. For a light truck tire it is 19.05 mm — three quarters of an inch, a blunt steel finger. For a large tubeless tire it can be 38.10 mm. For motorcycle tires it is 7.94 mm, five sixteenths of an inch. Roughly the diameter of a fat nail or a decent screw.
Table II then sets the minimum energy the tire must absorb before it breaks, and for the motorcycle column the numbers are 16 J for load range A, 33 J for B, 45 J for C. The neighbouring column — everything else of a similar rim size, tested with the 19.05 mm plunger — asks for 67, 135 and 203 J.
The honest reading matters here, so let me be precise: those joule figures are not comparable as “puncture resistance”, because the plunger diameters are different and a smaller plunger concentrates force into a smaller area. What the table does tell you is how the standard imagines the threat. Everything else on the road gets probed with something the size of a thumb. The motorcycle tire gets probed with something the size of the thing that actually goes into it in a car park, and the energies involved are in the tens of joules.
There is one more line in that test procedure that reads differently once you know the subject: “If the tire is tubeless, a tube may be inserted to prevent loss of air during the test in the event of puncture.” Even the laboratory expects the hole to go all the way through.
What the tire makers actually say about plugs
This is the section the first page of Google does not have.
Bridgestone publishes a Motorcycle Tire Safety and Maintenance Manual. Its section on repairs is a list of prohibitions, and two of them describe the roadside plug precisely:
Repairs of all tires (radial and non-radial) must be of the plug and inside patch type. Using plugs alone on any type of tire is not a safe repair.
Any tire repair done without removing the tire from the rim is improper.
A plug pushed in from outside, with the wheel still on the bike, is a plug alone and a repair done without removing the tire from the rim. By Bridgestone’s own definition it is both “not a safe repair” and “improper”. The rest of the section fences off the cases people argue about on forums:
Never repair a tire with a puncture larger than 1/4 inch (6.4 millimeters) in diameter. Such tires cannot be properly repaired and must be replaced.
Never repair a tire with a puncture or other damage outside the tread area.
Never repair a tire with less than 1/32nd inch (0.8 millimeters) tread remaining. At this tread depth, the tire is worn out and must be replaced.
And the reason, stated without softening: “Riding on an improperly repaired tire is dangerous. An improper repair can cause further damage to the tire. It may suddenly fail, causing serious personal injury or death.”
Now Dunlop. Its technical Care and Maintenance document runs to 35 numbered sections; section 13 is Tire Repair, and it is four sentences that no plug-kit review has ever quoted:
Some punctures in motorcycle tires may be repaired. Dunlop recommends only permanent plug-patch repairs of small (maximum 1/4-inch diameter) tread-area punctures from within the dismounted tire by a qualified tire repair shop or motorcycle dealer. Never perform an exterior repair and never use an inner tube as a substitute for a proper repair. Speed should not exceed 50 mph for the first 24 hours after repair, and the repaired tire should never be used over 75 mph.
Never perform an exterior repair. That is the entire product category — every kit, every reamer, every sticky rope — described in four words by one of the largest motorcycle tire manufacturers in the world. And a few lines later the document goes further, addressing dealers rather than riders:
Advise your dealers that no form of temporary repair should be attempted because secondary damage caused by a penetrating object may not be detected and tire or tube deflation may occur at a later date.
Michelin arrives at the same destination by a different route. Its guidance is friendlier about the kit — it accepts that you may be a long way from a garage — but it is blunt about what the kit is:
It is important to know that this type of repair can only be temporary. Firstly, because a wick inserted into the tyre in this way does not guarantee a complete seal. Secondly, because driving after a puncture without having the inside of the tyre checked by a professional is a major safety risk.
Three companies, one conclusion: a plug is a means of transport to a workshop, not a repair. The workshop repair, in every one of the three documents, involves taking the tire off the rim and working from the inside — Michelin calls its version a “mushroom” or PRP, “a stem fits into the hole to prevent air circulation and a flat part at the top seals the hole from the inside”, and notes it “requires access to the inside of the tyre (unlike the wick, which is inserted from the outside)”.
Dunlop against Dunlop
Here is the part I did not expect.
The page that ranks on the first page of Google for this subject, from Dunlop’s own site, is called “How to Carry Out Emergency Motorcycle Tire Repairs”. It is a good, practical, friendly article. It says:
Tubeless tire – Here, if the hole is ¼” in diameter or smaller, you can repair the hole in the tire with a plug. The good news is that you won’t have to remove the tire or wheel from the motorcycle.
It then lists four commercial repair kits by name so you can pack one.
The technical document on the same domain says “Never perform an exterior repair” and “no form of temporary repair should be attempted”.
I am not going to tell you one of those pages is a lie, because neither is. They are written for different readers with different problems: the technical document tells a dealer what a repair is, the consumer article tells a stranded rider how to get moving. But the two texts exist simultaneously, on the same website, giving opposite instructions about the same act — and only one of them is indexed on the query you typed. The consumer page does at least carry the qualifier in bold:
Important: Even if the puncture repair is successful, all the above repairs are temporary fixes to get you on your way to the nearest tire shop.
It also draws one line that everybody should know and half the internet ignores: “If, for instance, the puncture is in the sidewall, it’s game over. Whether the tire is tubed or tubeless, the sidewall and carcass strength are compromised if the sidewall has a hole.” Michelin draws the same line at the bead: if the bead is damaged and the tyre has come off the rim, it advises against a temporary repair with the kit and tells you to “have your motorcycle towed away by a breakdown service”.
This is the same pattern I keep running into on this blog — the chain manufacturer and your owner’s manual disagreeing about lubrication, the brake fluid job the schedules mention and nobody does. The documents exist. They just do not agree, and nobody puts them side by side.
The number that survives the repair: your speed rating dies
If there is one fact in this entire article worth remembering, it is this one, and I had never seen it stated anywhere before reading Bridgestone’s manual:
A tire’s speed rating is void if the tire is repaired, retreaded, damaged or abused, or otherwise altered from its original condition. Thereafter, it should be treated as a non-speed-rated tire. Speed should not exceed 50 mph (80kph) in the first 24 hours after a repair is made and the repaired tire should never be used at speeds above 80 mph (128 kph).
Dunlop says the same thing twice, once in the repair section and once in the section on speed ratings, where the ratings are described as “not valid for damaged, altered, repaired, excessively worn, underinflated or overloaded tires”.
So the W on the sidewall of a sports tire, the letter you paid for, is a property of a tire that has never been holed. Repair it properly, at a shop, from the inside, and it becomes a tire with a permanent ceiling — 75 mph in Dunlop’s document, 80 mph in Bridgestone’s. Not for a week. Forever.
That reframes the economics completely. The plug is not the cheap version of a new tire. It is the version where you keep a tire you must now ride differently for the rest of its life, on a machine where the rear tire is the one transmitting all the power and the front one is the one holding your steering.
How big is too big? Three companies, three answers
Everybody quotes a quarter of an inch. Two of the three sources agree with that. The third does not, and the difference matters on a modern bike.
| Manufacturer | Maximum repairable hole | Repair accepted | First 24 hours | Ever after |
|---|---|---|---|---|
| Dunlop | 1/4 inch (6.35 mm), tread area only | plug-patch from inside, tire dismounted, by a shop or dealer | 50 mph | never above 75 mph |
| Bridgestone | 1/4 inch (6.4 mm), tread area only | plug and inside patch, tire off the rim | 50 mph (80 km/h) | never above 80 mph (128 km/h) |
| Michelin | 6 mm below VR, 3 mm on ZR | mushroom / PRP from inside, by a professional | — | maximum two repairs in the tire’s life |
Michelin’s table is the one worth staring at. It sets the limit by speed rating: below VR, a 6 mm hole; on a ZR tire, 3 mm. And ZR is not exotic — the Yamaha MT-07, an ordinary middleweight, runs 120/70 ZR17 at the front and 180/55 ZR17 at the rear, and its owner’s manual lists the Michelin Pilot Road 3 among the approved fitments. On that bike, from that tire’s own maker, the largest repairable hole is three millimetres. Half the quarter-inch figure the internet repeats.
Michelin adds a limit nobody tracks: “It is not recommended to repair a motorcycle tyre more than twice.” Two. Which raises an awkward question — do you know how many times the tire currently on your bike has been repaired? If you bought the bike used, you almost certainly do not.
And there is a failure mode that happens before the repair even starts. If you keep riding on a soft tire, Michelin warns, it can produce “mottling on the inside of the tyre”, meaning “the cords that structure the tyre inside the rubber have been badly deformed” from heat. In that case “the professional will not advise repair because the tyre has become dangerous to drive on”. The damage that stops a repair is not the hole. It is the distance you rode after the hole.
Sealants, according to the company that sells you the tire
Aerosol and liquid sealants are the other half of the roadside industry, and here the manufacturers are less ambiguous than about plugs.
Dunlop:
Dunlop does not recommend the use of liquid sealants. These are a form of temporary repair, and they may adversely affect ply material and mask secondary damage caused by a penetrating object. Advise your customers that reliance upon sealants can result in sudden tire failure and accident.
Bridgestone approaches it from the side of the person who has to work on the wheel afterwards, and the warning is a safety one for them rather than for you:
Before having a tire repaired, tell your local dealer if you have used an aerosol fixer to inflate/ seal the tire. Aerosol fixers could contain a highly volatile gas.
Michelin is the most permissive, describing sealant as a product that can be used preventively or curatively and noting that it evaporates over time, so “from time to time” you have to check it has not dried out. Even there, the framing is a product with a maintenance requirement of its own, not a fix.
Then there is the paperwork. Dunlop’s warranty page lists what is not covered, and the list includes “tires injected with dry/liquid balancers or sealants, or in which anything other than air has been used as the supporting medium”. It also excludes tires “rendered unserviceable by road hazard–type damage such as impact breaks, punctures, cuts, or snags”, and — a phrase worth underlining — damage caused by “running while flat”.
Who owns the tire after you plug it
One sentence in Dunlop’s technical document answers the question everybody is really asking when they type is it safe to plug a motorcycle tire:
The repairer is solely responsible for the repair and any instructions to the repaired-tire user.
The repairer. Not the manufacturer, not the shop that sold you the kit. Dunlop’s warranty text repeats it in legal register: “The serviceability of any repaired/retreaded/altered tire is entirely the responsibility of the person making the repair or modification.”
The moment you push a plug into your own tire, you are the repairer. That is not a threat, and it is not a reason never to do it — it is the accurate description of what changes. You have taken a component certified by a manufacturer against a federal standard and turned it into something certified by you.
For reference, Dunlop’s warranty runs to “six years or 72 months of the date of manufacture”, and stops entirely once the tire is “worn beyond the last one thirty-second of an inch (1/32″) of original tread depth”. Which leads straight into the most confusing number in this whole subject.
When is a tire too worn to repair? Pick a number, any number
Bridgestone will not repair a tire with less than 0.8 mm of tread left. That sounds generous until you notice that four different authorities put “worn out” in four different places on the same tire.
- FMVSS 119, section S6.4: motorcycle tires need “at least three such indicators which permit visual determination that the tire has worn to a tread depth of 0.8 mm (one-thirty-second of an inch)” — while every other tire in the standard gets six indicators set at 1.6 mm. Three instead of six, at half the depth.
- Bridgestone: remove from service “once the wear reaches the tread wear indicator bars (indicating 1/32 of an inch of tread depth)” — so 0.8 mm, matching the federal indicator.
- Dunlop, section 9: “Dunlop recommends replacing a tire when it is worn to 2/32 of an inch of tread remaining” — 1.6 mm, twice the indicator.
- Yamaha, in both the 2014 MT-07 manual and the current XSR900 GP manual: “Minimum tire tread depth (front and rear): 1.6 mm (0.06 in)”, with the note that “the tire tread depth limits may differ from country to country. Always comply with the local regulations.”
And the law adds a fifth number. The DVSA’s MOT inspection manual for motorcycles requires a tread pattern “of at least 1.0mm throughout a single band of at least 3/4 over any section of the breadth of tread round the entire outer tyre circumference” — with a genuine curiosity attached: “Motorcycles with an engine capacity not greater than 50cc do not need to have 1mm of tread.” A fifty needs only a visible pattern.
Put those together and the practical consequence for a puncture is uncomfortable. The tire most likely to pick up a nail is the one nearest the end of its life, because there is less rubber between the road and the carcass. That is also the tire Bridgestone forbids repairing, and the one Dunlop thinks you should already have replaced. Half the plug decisions people agonise over are actually tire-replacement decisions that arrived early — which is the same conclusion the tire guide on this blog reaches from the other direction.
What a roadworthiness test actually looks at
I expected the British MOT to have an opinion about repaired tyres. It does not.
Section 5 of the DVSA’s motorcycle inspection manual covers wheels, tyres and suspension in 2,562 words. The word “repair” appears in it only in the suspension and fork sections, in the phrase “Unsafe modifications include: welded repairs”. The list of tyre defects runs from (a) to (k) — unsuitable tyre, twin wheel mismatches, a cut deep enough to reach the ply or cords, a lump or bulge or tear, tread depth, a tyre fouling another component, a recut tread, non-compliant fitment, the valve, a tyre not properly seated on the rim — and there is no entry anywhere in it for a tyre that has been plugged, patched or sealed.
I am describing the structure of a document, not handing out legal advice, and roadworthiness rules differ by country. But it is worth knowing that the inspection which is supposed to catch dangerous tyres is built around cuts, bulges, depth and fitment, and simply does not contain the category everybody worries about. A plug in the tread does not produce a listed defect. Whether it produces a safe tyre is a question the manufacturers answered in the sections above, and the test never asks.
Two things in that list are marked “Dangerous”, the most serious category. One is “a tyre with a lump, bulge or tear caused by separation or partial failure of its structure”. The other is the one nobody checks:
A tyre valve seriously damaged or misaligned likely to cause sudden deflation of the tyre — Dangerous
The valve. Yamaha agrees, in language that reads like an afterthought until you understand it is not: “Always make sure that the valve caps are securely installed to prevent air pressure leakage” and “use only the tire valves and valve cores listed below to avoid tire deflation during a high-speed ride”. The MT-07’s manual then names the parts — valve TR412, valve core #9100. A rubber valve stem is a consumable that ages, cracks at the base and lets go, and it is the one cause of a flat that a plug kit cannot touch and a pre-ride glance can catch.
Your own manual already answered this
Every rider has a document at home that gives a direct instruction about a nail in a tire, and almost nobody has read it.
Yamaha’s MT-07 manual, printed in October 2014, and Yamaha’s XSR900 GP manual, a current-generation bike, contain the same sentence, word for word, a decade apart:
The tires must be checked before each ride. If the center tread depth reaches the specified limit, if the tire has a nail or glass fragments in it, or if the sidewall is cracked, have a Yamaha dealer replace the tire immediately.
Replace. Not repair. The manufacturer of the motorcycle, unlike the manufacturers of the tires, does not offer a repair path at all — it offers a dealer and a new tire. The same section adds that “the replacement of all wheel and brake-related parts, including the tires, should be left to a Yamaha dealer, who has the necessary professional knowledge and experience to do so”.
The absence is as telling as the presence. Across both manuals the word “repair” appears fourteen times in one and thirteen in the other, and never once about a puncture: it is about the wheel, the fork, the steering and winter storage. “Puncture” and “patch” appear zero times in either. And where Yamaha does want to forbid a repair, it says so explicitly — about the wheel, not the tire: “Do not attempt even the smallest repair to the wheel. A deformed or cracked wheel must be replaced.”
So the hierarchy of documents, from most permissive to least, runs: consumer blog page, tire manufacturer’s technical document, motorcycle manufacturer’s owner’s manual. The further you get from the person trying to keep riding today, the shorter the list of acceptable answers becomes.
So what do I actually do at the side of the road?
This part is mine, assembled from the documents above rather than quoted from them. It is what I have settled on, and it is deliberately boring.
- Stop the way the manual says. Firm grip, throttle off, straight line, brake on the good tire if you must brake, then edge off the road, clutch in, stop. Decisions come after the bike is still.
- Read the sidewall before touching anything. Tubeless or tube type. If it says tube type, the kit in your bag is the wrong kit and the answer is a recovery truck or a wheel out.
- Look at where the hole is, not how big it is. Sidewall or shoulder means it is over — Dunlop’s “game over”, Michelin’s T-zone that excludes “the edge of the tread and the sidewall”. Only a hole in the middle of the tread is even a candidate.
- Check whether the tire was worth saving anyway. If it is near the wear bars, Bridgestone will not repair it and Dunlop thinks it should already be gone. That converts the question from can I plug this into can I get somewhere that sells tires.
- If I plug it, I treat it as a tow rope, not a fix. Slowly and steadily to a shop, which is Dunlop’s own phrase on its consumer page, with the tire coming off the rim and being inspected from the inside by somebody who does it for a living. Michelin’s mottling warning is the reason the inspection matters more than the plug.
- After a proper repair, I remember the ceiling. 50 mph for the first day, and permanently below 75 to 80 depending on whose document you follow. If that ceiling does not fit how I use the bike, the repair is not the cheaper option — it is the option that quietly changes the motorcycle.
- I carry the kit anyway. All of the above is about what a plug is. None of it argues for being stranded at dusk on a road with no phone signal, which is a real risk with its own real consequences — the same reason a first aid kit lives in the luggage on a long trip. The kit is transport, and knowing that is what makes it safe to carry.
None of this is exotic mechanics. Reading a sidewall, finding the wear bars and looking at a valve stem belong in the same drawer as the ten operations worth learning to do yourself, and they take about as long as the spring check that follows winter storage.
Where an app comes into this, honestly
Three questions in this article need a record, and none of them can be answered by looking at the tire.
How many times has this tire already been repaired? Michelin’s limit is two, and the tire does not keep score. When was it fitted, and what has it actually done since? Dunlop’s warranty counts from the date of manufacture and runs six years; its inspection advice kicks in at five. And how much riding is on it — not the odometer, which counts the bike, but the distance since these tires went on?
RideLog is the app I built for this kind of bookkeeping. It detects rides automatically through the phone’s motion sensors and GPS, so the distance accumulates without you starting or stopping anything, and the maintenance reminders explicitly cover tires alongside the service, the insurance and the road tax. Everything stays on the phone — no server, no account, no cloud — which also means it keeps working in the exact situation this article is about, which is you, a long way from anywhere, with no signal.
What it does not do, and I would rather say it than have you discover it: it does not read tire pressure, it has no TPMS integration, and it will not tell you that you have a puncture. Nothing on your phone will. That job belongs to your eyes before the ride and to the handling change described at the top of this article during it.
The unglamorous conclusion
A motorcycle flat tire has one famous answer and it is the wrong shape. The plug is not a repair; it is a way of moving a damaged tire to a place where somebody can look inside it. Bridgestone writes that plugs alone are “not a safe repair” and that any repair done without taking the tire off the rim is “improper”. Dunlop writes “never perform an exterior repair”, and then publishes a separate page telling riders how to perform one. Michelin says a wick “does not guarantee a complete seal”. Yamaha, asked directly what to do about a nail, says replace the tire.
None of that means you should throw the kit away. It means the kit is a get-home tool with a speed limit and an expiry, and that the real decision — repair properly or replace — is taken later, off the bike, with the tire in somebody’s hands and its inside visible.
If you take two things from this: find out today whether your tires say tubeless or tube type, because that determines which tool is even relevant, and look at the base of both valve stems, because that is the failure the roadworthiness test calls dangerous and the plug kit cannot fix. Then, if you want the fitting date and the mileage on your current tires to stop living in your memory, download RideLog free and put them next to the rest of the bike’s dates.
And if you enjoy this kind of thing — reading what the documents actually say instead of what everyone repeats — the same treatment is here for what the service schedules really contain, how long a helmet really lasts and the clutch that cannot be adjusted at all.
Frequently asked questions
Can you plug a motorcycle tire?
Physically yes, and the roadside kits sold everywhere are designed for it on tubeless tires. But the manufacturers do not treat it as a repair. Bridgestone writes that “using plugs alone on any type of tire is not a safe repair” and that “any tire repair done without removing the tire from the rim is improper”. Dunlop’s technical Care and Maintenance document says “never perform an exterior repair” and that “no form of temporary repair should be attempted”. Michelin says a wick inserted from outside “does not guarantee a complete seal”. The consistent position across all three is that a plug gets you to a workshop, where the tire comes off the rim and is repaired from the inside.
Is it safe to ride on a plugged motorcycle tire?
Only as a means of reaching a tire shop, and only slowly. Dunlop’s consumer guidance describes a roadside repair as making the tire “functional enough to ride slowly and steadily to the nearest shop” and states that all such repairs “are temporary fixes”. After a proper workshop repair there are explicit speed limits: Bridgestone says speed “should not exceed 50 mph (80kph) in the first 24 hours after a repair is made and the repaired tire should never be used at speeds above 80 mph (128 kph)”; Dunlop gives 50 mph for 24 hours and never above 75 mph.
Can you drive a motorcycle with a flat tire?
The MSF Motorcycle Operator Manual treats a flat as an emergency to be brought to a stop, not a condition to ride in: hold the handgrips firmly, ease off the throttle, keep a straight course, brake only on the tire that is not flat, then edge to the side of the road and stop. Michelin adds a mechanical reason not to continue: riding on a deflated tyre can produce “mottling on the inside of the tyre”, meaning the structural cords have been deformed by heat, after which “the professional will not advise repair because the tyre has become dangerous to drive on”. Dunlop’s warranty also excludes damage caused by “running while flat”.
How big a puncture can be repaired on a motorcycle tire?
It depends whose document you follow. Dunlop allows “small (maximum 1/4-inch diameter) tread-area punctures”. Bridgestone says “never repair a tire with a puncture larger than 1/4 inch (6.4 millimeters) in diameter”. Michelin sets the limit by speed rating instead: 6 mm for tyres below VR, and only 3 mm for ZR tyres — which covers a great many ordinary sports and roadster fitments. All three refuse repairs outside the tread area entirely.
Can a motorcycle tire sidewall puncture be repaired?
No. Dunlop’s guidance is blunt: “If, for instance, the puncture is in the sidewall, it’s game over. Whether the tire is tubed or tubeless, the sidewall and carcass strength are compromised if the sidewall has a hole.” Bridgestone says never to repair “a puncture or other damage outside the tread area”. Michelin restricts repairs to the T-zone, “about three quarters of the tread”, explicitly excluding the edge of the tread and the sidewall.
Does repairing a tire affect its speed rating?
Yes, permanently. Bridgestone states that “a tire’s speed rating is void if the tire is repaired, retreaded, damaged or abused, or otherwise altered from its original condition. Thereafter, it should be treated as a non-speed-rated tire.” Dunlop says the same in its section on speed ratings, describing the S, H, V and Z ratings as “not valid for damaged, altered, repaired, excessively worn, underinflated or overloaded tires”.
How do I know if my motorcycle tire is tubeless or tube type?
It is written on the sidewall, because the American federal standard requires it. FMVSS 119 lists among the mandatory markings “the words ”tubeless” or ”tube type” as applicable”. The same standard allows motorcycle tires to carry their markings on only one sidewall and to use the entire sidewall area, so if you cannot find the word on the side facing you, check the other. It matters because a plug seals the carcass of a tubeless tire, while on a tube-type tire the leak is in the tube inside and the wheel has to come off.
Are tire sealants a good idea on a motorcycle?
The tire makers are cautious. Dunlop “does not recommend the use of liquid sealants”, describing them as a temporary repair that “may adversely affect ply material and mask secondary damage caused by a penetrating object”, and warns that reliance on them “can result in sudden tire failure and accident”. Bridgestone asks riders to tell the dealer if an aerosol fixer has been used, because “aerosol fixers could contain a highly volatile gas”. Dunlop’s warranty excludes tires “injected with dry/liquid balancers or sealants”. Michelin is more accepting but treats sealant as a product that dries out and needs checking.
How many times can a motorcycle tire be repaired?
Michelin’s guidance sets a limit of two: “It is not recommended to repair a motorcycle tyre more than twice.” Neither Dunlop’s nor Bridgestone’s documents give a count, but both restrict repairs to small tread-area punctures on a tire with enough tread left. On a used bike this is a question you often cannot answer, which is an argument for keeping a record of what has been done to the tires you fit.
When is a motorcycle tire too worn to be repaired?
Bridgestone draws the line at the wear indicators: “never repair a tire with less than 1/32nd inch (0.8 millimeters) tread remaining. At this tread depth, the tire is worn out and must be replaced.” That 0.8 mm is the depth at which FMVSS 119 requires motorcycle tread wear indicators to become visible. Dunlop recommends replacing at twice that, 2/32 of an inch, and Yamaha’s manuals specify a 1.6 mm minimum while pointing out that legal limits vary by country — in the UK, the MOT requires at least 1.0 mm across three quarters of the tread breadth.
What does an MOT check about a repaired tyre?
Nothing. The DVSA’s MOT inspection manual for motorcycles lists tyre defects from (a) to (k) — covering unsuitable tyres, cuts to the ply or cords, lumps and bulges, tread depth, recut treads, fitment and the valve — and contains no entry for a tyre that has been plugged, patched or sealed. The only “repair” mentioned in that whole section is welded repairs to suspension components. Two tyre defects are graded Dangerous: a lump, bulge or tear caused by structural failure, and “a tyre valve seriously damaged or misaligned likely to cause sudden deflation of the tyre”.
What does my motorcycle’s owner’s manual say about a nail in the tire?
If it is a Yamaha, it says to replace the tire. Both the 2014 MT-07 manual and the current XSR900 GP manual carry the identical sentence: “If the center tread depth reaches the specified limit, if the tire has a nail or glass fragments in it, or if the sidewall is cracked, have a Yamaha dealer replace the tire immediately.” Neither manual mentions repairing a puncture anywhere — the words “puncture” and “patch” do not appear in either — and both state that tire replacement “should be left to a Yamaha dealer”.
