Attack of the mutant stealth thorns!

Paul E.

Active Member
The other day I was riding home from work when I heard a twig get stuck in a tire again but it fell off after a second or two before I had time to stop. I have tire liners and everything seemed fine until the next morning when the tire was flat. Ok, slow leak then. Drive to work that day in the maddening traffic jam and fix the tube in the evening...

Took the tube out, found the puncture, patched it, put the tube back in, inflated it. Everything seemed fine but after a while the tire was flat again. So it was two punctures I thought, found the second one and patched it, put the tube back in and inflated. This time I could hear the leak hissing. WTF?

Upon closer inspection I found a thorn sticking inward from the tire through the liner, snapped off so there was no sign of it on the outside and it was dried out just perfectly to achieve maximum strength and sharpness so even the Rhinodillo liner was no match for it. Life found a way, and I learned to check what's in the tire when there's a hole in the tube.
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Active Member
Yes , I learned that from an early age! Always check the inside of the tire. And here is a tip, if you do not already know it. When you rub your hand inside the tire, use a rag to do it. It will save your fingers from getting cut by glass, nails, screws, thorns . Or anything else sharp stuck it there. Ken. Keep looking up!

NYC Rider

Learned about thorns this month. Recurring slow leaking flats and patches had me stumped. The tire was clean, but when I compared the location of the tube puncture to the tire, I found the tiniest thorn. Then I put on my reading glasses and did a more thorough search. I found about 6 of them, not all poking through. The thorns you see and avoid when hiking are much bigger than these. I picked them up biking in state land that has some equestrian trails and very overgrown fire roads and paths. Since my Neo Jumper can handle anything, I rode over immense quantities of dried brush.

The location is state land north of Fairview Park, Staten Island. The sign reads horses and pedestrians only, so naturally I felt I belonged. On a Saturday afternoon in 70 degree sunshine I had the whole place to myself, but all the paths off the horse trail were completely untrampled and covered in years old dead growth. I easily crunched over it all, but got my reward with a recurring flat tire. Since I am now in the habit of at least carrying a pump I was not stranded or forced to find the nearest rapid transit station (or god forbid a thousand times, resort to calling a cab).

I took pictures of what these things look like. The larger thorn is 6mm long. The smaller one has a tiny seed attached to it. On the exterior of the tire I found tiny tan colored specs that were the tops of thorns not fully penetrating my Rapid Rob tire. New Smart Sam Plus tire is on order.!1sH6u2_7_Y7eswtc2iwX2A6A!2e0!7i3328!8i1664
Englewood Avenue at Veterans Road West. Don't go in there, but do go to nearby Bloomingdale Park or Wolfs Pond Park (MTB trails).


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Active Member
Yeah, you want to play you have to pay.
It sure looks like a fun place to ride, if you like the off road stuff. To bad about all the stickers there. Maybe if you go around them instead of on them.:D
I stay on the road my self. Still manage to get flats every once in awhile . Had two different times I got tiny wire from some car driver going on bald steel belted tires, and leaving little tiny wires all over Sebastian .:confused: Keep looking up! Ken.

Ann M.

Well-Known Member
Tire liners are a must! There's all different kinds and my mountain biking buddies like to go tubeless and use some sort of sealant (sorry that's not my area of expertise :) being primarily a roadie type). With tubeless you can plug it like a car tire.


New Member
err... I also use petrol M'bike, got flat tyre, turns out to be from thorns, they fitted inner-tube to what was tubeless, only'd that tyre for few weeks, cost more to repair than new!


New Member
Not any more flat tyres, could just be 'cos = longer since hedges cut.
Same problem + moped in 70's.
Take mobile phone + dad's N°. (found whole spear wheel on E-bay before, but didn't buy it then.)
Brits've newer spelling of tire for rubber 1s.