Dear MOby,

Yes, I have a question that’s, weirdly enough, only now occurred to me after 20-plus years of riding, as I contemplate yet another sheet metal screw embedded in my almost new rear Dunlop Q3 Plus tire. Why do nails and screws always wind up in the rear tire? Is it because it’s the most expensive one and the harder one to change? Do rears have thinner carcasses? I can’t remember ever having a hole in my front tire. Help me understand…

Screwed Again
In the Rear


Dear Screwed,

This is one of those pieces of moto knowledge handed down from the ancients, which, after you’re enlightened, seems so self-explanatory. Without this wisdom, it’s so easy to blame fate and the gods, to develop an unhealthy persecution complex, to begin to mistrust and hate one’s fellow beings.

This is why your rear is always the tire with the nail in it: Your front tire rolls over the nail or screw lying there benignly on its side in the road, and kicks it up at occasionally just the right angle and timing for it to insert itself into your rear tire.

The only time you’re going to get a nail in your front tire is if you’re following the roofing truck just as the one with your name on it falls off and is still bouncing merrily along.

Follow me to the new tire store! Photo by: Nitinut380/Bigstock.com

The only known way to avoid getting fasteners in your tires is to carry a tire repair kit at all times. It’s not a foolproof prophylactic, but it is 94.2% effective in MO testing.


Send your moto-related questions to AskMOAnything@motorcycle.com. If we can’t answer them, we’ll at least make you feel temporarily better by thinking you’re talking to somebody who knows what they’re talking about even if we don’t. And if we’re wrong, some smart aleck like Dick Ruble will let us all know immediately.

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  • frankfan42

    The driven forces of the rear tire also lend the impetus for sharp objects to imbed themselves in the tire as well.

    • Stuki Moi

      And the rear tire is also normally wider. Hence has a larger patch flat enough to the ground where it won’t spit a nail out to the side.

      • frankfan42

        That makes really good sense as well.

      • toomanycrayons

        I get flats front and back at about the same rate with equal-sized cycling tires. Front flats are the most exciting, especially downhill.

        It seems that the newer the $75 Conti road tires are the more likely they are to catch a nail/screw/ghost-holers, unless they’re a “Gator” version.

        Rather than roadie karma, I’m thinking the ample, smooth-riding compound GRABS the sharp things just as well as it does the asphalt.

        With that in mind, and to the HORROR of the local shop, I ride the training rears, at least, right down to the sight of some threads. Never had a nail in worn out rear tire. No rubber on a front is just CRAZY!

        Having posted that, I feel compelled to revisit my under seat spare tubes, tools and patch kit. I know how this works…

        • ‘Front flats are the most exciting, especially
          downhill.’ I dare not ask what you find most frightening :).

  • Jon Jones

    When the economy is good and there’s lots of construction, there’s always more debris on the road to impale your tires.

  • allworld

    I don’t think I have ever had a rear tire without having to put a plug in it, prior to replacement.
    I do carry a a repair kit and pump……….. sort of ATGATT for your bike.

  • halfkidding

    I have carried a tire plug tool for years and have never used it, which goes to prove your point. Now excuse me while I go knock on some wood and hope like hell I have not jinxed myself.

    • clasqm

      A can of tyre foam zip-tied to a frame tube works just as well!

      • I used Foam once – never again. The tin said not to exceed 80 kph (50 mph) which I found a total PITA all the way home. I was told that I could leave the goo in the tire and just plug it in order to run at proper speeds again. And then when I had plugged it, I found the Wheel Balance to be WAY off. I decided to pull the tire off, only to find an ungodly mess in there. Some of it had congealed in little balls and clumps and some of it still liquid. Sticky like Builders Foam and smells like something had died in there. Took me forever to clean up the tire, rim (and everything else) and I had to replace the Valve and Core. Probably OK for Tubes (given the time that Foam entered the Market) but not recommended for Tubeless Tires.

        I now carry a Plug Repair Kit with me. Just make sure that you stick as many CO2 cartridges in there as you can – no less than 6. Better still a small Pump. Test the Pump at home first before you need to rely on it and find that it does not reach the pressure that you need – or that you have not got a proper electrical connection for its leads fitted on your Bike. Also puncture and practice an actual Road Repair at home next time you need to replace a Tire – on the old one before removing it. It will bring out several Lessons Learnt close enough to your Garage. Don’t ask how I know. Once you are properly equipped and ride fully prepared, you will never have a puncture again. It is the way the Cosmos operates, that.

        • Gootch

          Tire foam doesn’t work well on tubes. I’ve tried on four different flat tubed tires and it worked one time — well enough to get me home from work. They were all rear tires too (three on a Thruxton and one on a KLR).

          • You need to convert to Tubeless if you can. That is if your Rim Profiles are suitable for running Tubeless Tires.

            I’ve done the conversion on my Chief Vintage which has Spoked
            Wheels, using the OUTEX Conversion Kit. I bought it direct from Ronin Cycles, in Japan, choosing the closest H-D Matchup available on their site.

            They work well and are especially popular with Ducati Owners
            running older models with Laced Wheels. They are often fitted to Track Bikes and have proven reliable under that abuse and heat. I’ve had mine on close to a year now.

            It is a careful Install – no Practice Runs or Retakes. But I got it done, so anybody can. Reserve a full day for it, take your time, read and understand the Instructions and watch the You Tube Clips.

  • JMDGT

    Single sided swingarms are your friends.

    • Dwight Nevins

      Unless it’s on a BMW

    • Douglas

      Rear flats are the reason EVERY bike should come standard with a center stand. If you’re such a diehard traditionalist (“No damnable metric-style sissy stand on MY Hog, by God!!), just remove it. Then there’s “My Road Glide or my Roadmaster or my Voyager or whatever is too heavy for that!” B.S. If you can raise a GoldWing on a centerstand, you can raise anything.

  • Ron Austin

    It’s not rocket science. The front tire kicks it up, the rear tires picks it up. Happens to our cages too but we don’t tend to notice them as much. Prime times for flat tires are after major storms when there a bunch of folks repairing their roofing damage. Never fails.

  • Dwight Nevins

    I USUALLY try to think the best of Humanity
    BUT I couldn’t help but wonder if a tire shop owner , who’s business may be in the doldrums , might invest in a box of roofing nails to stimulate his personal economy

    • HazardtoMyself

      Went into a small shop once for an inspection after moving to a new state.

      Was talking to the guys about riding areas and their shop as I wanted to find a good mechanic in the area. Several said one of biggest problems is nails and screws everywhere.

      Passed inspection and went home, only to find a nail in the rear tire. While I hope it was not intentional, I never went back to that shop again.

  • Eric

    When I lived in Phoenix during the late 90’s, I caught nails in my rear tire about every three months! They were in a major bulding boom, and there was always construction debris on the roads. I finally started riding in the same wheel position as the cars, and this made a big difference. I guess the cars were catching most of the nails for me…I don’t know, but it seemed to work!

  • Myk DeVroede

    Be grateful it’s the rear tire, front end flats are a lot harder to control to a stop.

  • michael32853hutson@yahoo.com

    in the olden days bikers carried that extra tube or two,nowadays the tubeless repair kit is the lick;and they work but if you have room tire sealant is a way to play it safe(use both!)one of those portable tire fillers that looks like a cordless drill wouldn’t hurt either if you have room in the bags

  • huesos threefity

    well nail/screws would be nice change of things. i have gotten slugs (knock outs of electrical boxes), a quarter, and small metal rod absorbed into the tire. only the slug managed to cut into the tire. i have to add that this occurred during a particularly hot summers here in the Imperial Valley, i believe the temp was about 116-ish at 4pm when i was riding home (20 miles on asphalt). the tire compound was very gummy, i could grab a section from the center of the tire and pull it out a 5 to 6 inches.

    • Jon Jones

      Made me chuckle!

  • bvail

    Ride-on dot com. Used it on all my bikes.

  • Dootin

    I thought it was because the rear tire is closest to the muffler bearing.

  • Walter

    Even though you screwed up with the picture, you nailed the explanation.

  • kenneth_moore

    About tire repairs on the road: last May I was riding to The Dragon with a friend from Florida. He got a flat (the rear, of course) early Sunday morning outside Spartanburg. He had a small kit under his seat not much bigger than a pack of smokes. It had a mini jack-stand, a set of tire plugs that I’d never seen before, and a mini 12 vdc air compressor. The mini jack-stand has a bar that goes in the hollow axle and that, with the kickstand, got the rear wheel up. The plug tool was about the size of a standard Phillips screwdriver, and the plug itself was a tiny black rubber blob, which pushed into the hole. The mini compressor was slow, but it worked. We were stopped less than 30 minutes.

    One note: the compressor had a cigarette lighter connection, but it draws way more current than most 12 vdc sockets are fused for. It burned out my FJ socket fuse instantly.

  • michael folk

    buy a fail safe tire and you dont have to worry to much the air goes out and you continue on for up to 500 miles ,but then it is hard to see if it is flat and you need to use the air pressure guage

  • Sloan Essman

    I fell into the remaining 5.8% last weekend! BUT at least I had the tools to patch it up and get home.