Yet another flat - HELP!

Everytime its from a stand still on flat ground and giving it average throttle, not w.o.t. I ease into the throttle normally. It is def not punctures, more like pinch flats. Too many flats. I believe its from the tire rotating in the rim, as the tube itself stays with the rim because of the valve.

Pictures - The blue is where I got the flat. In the case of the first pic, its the usual sidewalk ramp that is angled as shown in blue, and I got the flat powering up a little bit from the middle of the crosswalk, felt flat at 2nd ramp, half flat halfway up to next corner, full flat a few feet after that.

Second pic I was at a little bit of an incline, stopped, feet off ground, hand on pole, pushed off which didnt help much if any. Felt something not right and fast flat by other side of road.

Brand spanking new Continental tube, brand new tire.
400lbs, plus bike, + mxus 3kw motor (rear), + 15S8P Liion battery, all in 26" Crystalyte rim, hksunwin controller, 61V full, LVC at 41V. Townie 21D bike, feet forward design, so all the weight is on the rear wheel. Rim is smooth, used brand new rim tape, double wall rim is very deep, spokes are tight. Inspection of all the flats always looks like pinch flat. Installation of tube, has always been double checked, last 10 flats were all triple checked and checked again. Total number of flats, I am embarrassed to say

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I was planning to go 16 x 1.60 motorcycle rim and Shinko 244 which is 3.0 but that might not solve the issue, because I gain more torque going from 26" bicycle to 16" moto.

Do you guys think 2WD where if I am stopped, I use front motor, then cruising use rear.

Trucks can use bead lock Never seen that with motorcycles or bicycles.

You should post pics of wheel/tube instead of where you got the flats.

Tube: You need thick DH type, ideally with metal stem. Metal stems have a nut, that is keeping the tube from spinning on the rim in hard acceleration. Alternatively, you can use a tacky spray for belt conditioning. Spray little of it over the rim tape and rim bead slot.

Add Green slime in tube, 4 oz max, 2 oz if tire less than 2.3

Tire: too high PSI makes it easy to puncture
Too low PSI pinches on curbs and square obstacles. You can see when low PSI is the cause because the rim has marks or dents.


Check inside tire for any debris, and if something (nail/glass...) is still pointing in.

Once mounted and inflated, check that tire bead is well seated.

Thanks MadRhino, Will Do!!

Do you think hair spray would work instead of tack?
Got one last tube left. Plus need transportation tomorrow, gotta baby the frock out of it now to get it up to speed.

The tube I had did have stem nut, tire was a 1.95.

These pictures were from the first flat in the original post, about 2.5" away from stem at the 3/9 o'clock (stem down) walked bike to a Car2Go 50' away. Havent bothered with current flat, disappointed, and bummed out is all.

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Purchase List
Tack - http://www.canadiantire.ca/en/pdp/motomaster-belt-dressing-170g-0383810p.html
Slime - http://www.chainreactioncycles.com/ca/en/slime-puncture-preventor-tube-tyre-sealant/rp-prod133437
$15 DH Tube w/nut - http://www.chainreactioncycles.com/ca/en/continental-mtb-26-tube/rp-prod18901
$15 DH Tube w/nut - http://www.chainreactioncycles.com/ca/en/maxxis-dh-mtb-tube/rp-prod5418
Cheaper $6 DH Tube w/nut - http://www.chainreactioncycles.com/ca/en/lifeline-dh-mtb-tube/rp-prod157382

Consider that you may have pinched the tube between the tire bead and rim when mounting. You have to inflate the tube a little air before fitting it inside the tire, to make sure it doesn’t twist or pinch.

Then, if you has twice the same flat at the same spot on the wheel, you need to check the tire and rim for imperfection. A broken wire can point out of the tire bead, or a scratch in the alu can lift a sharp edge.

Downhill and Freeride tubes are thicker than MTB, and usually more expansive. I like the Kenda, Nokian, Maxxis, Michelin... DH specific. Ideally, the tube and tire are perfect size match. I mean, too big a tube does make folds and too small gets thin.

All those things on your list, are normally available locally and don’t need to be ordered from the other side of the world.

When your tire and tube are quality, mounted and inflated properly, with a little slime in, flats are really not often unless you are riding desert areas or places that have a lot of hard thorns.

I hope I don't sound too rude, but I think you need to consider that you are too big for your equipment.
I would think moped/motorcycle wheels would be your next step.
Actually, you may be exceeding the weight limits for your bikes. It's not a usually prominently displayed number, but most bikes I'm familular have a rider weight limit of 300 lb.s.
Maybe a purpose built ebike would be a sensible goal.

Possibly not a consensus decision, but when I got five flats one week (before e-bikes), I installed a Stan's kit (this was before tubeless rims were readily available). This solved the problem; no flats for two years or so.

I've damaged a tube sooooo many times mounting it. But in recent years, say the last 15 years, too many tubes just have a flaw in the rubber.

This looks like a flawed tube to me. I got the frequency of that problem to be less, but not eliminated by buying quality brand tubes at the most popular bike shop in town. Tubes are like bread, stale ones suck. So I get them where they are fresh, and staff rotates the stock properly. Not Walmart, where the last tube on the shelf might have been there years.

If that problem happens at the point on the tube right at the rim, then its a pinch flat.

FIFO - First In First Out (a few really good stores)
FILO - First In Last Out (some stores)
FISH - First In Stays Here (everybody else)

As far as the flats go, do you have any lose spokes? Did you re-tape the rim to prevent the spokes from rubbing the tube? When you put the tire on are you sure the rim and tire was seated properly? Did you check the air to make sure the tire was inflated properly before the ride? (Low pressure allows tires to slip on the rim). Were you sure the inner side of the tire was free from debris when you reinstalled it?

Lots of things cause flats like that. Good luck running it down.

FWIW Dirt bikes use a bead locker all the time. Pain in the rump to install too.

Moto setup its gotta be then, in the meantime I will do whats suggested and just not power from a stop anymore with bicycle setup.

I order from Chain Reaction all the time, dirt cheap prices and always comes in a few days from Ireland. They seem to be out of Slime, so local bike shop is $5 more. Tires are usually 33-50% cheaper.

FWIW I pinched more tubes installing bead lockers on dirt bikes than I ever did by pinching tubes on a bicycle.

Whatever you decide, good luck.

Looks like a cheap tube. Try a downhill tube before you go crazy

markz said:

Moto setup its gotta be then, in the meantime I will do whats suggested and just not power from a stop anymore with bicycle setup.

Click to expand...

I use bicycle rims and tires, power much higher than you will ever do, and have flats once every second year, riding a lot of mileage.

Your problem has nothing to do with bicycle stuff, and the only reason to go heavier is to limit tire changes, at the cost of performance and efficiency loss.

It looks like a pinch, which could be from mounting with tools (NEVER necessary with 26" bicycle tires), or could be from bottoming the rim on the ground due to inadequate tire pressure.

How much pressure are you using? I weigh close to 350 lbs and I usually use about 40psi front, 50psi rear in 26x2"-ish tires.

Note that if you take care to move the tire bead wires to the deeper area in the center of the rim, you'll always have enough slack to lift the last bit over the edge by hand. But don't prevent this by using too much/too thick rim tape.

I think what everyone here except Chalo don't realize, is that Mark stated in another thread that he weighs 388 lb.s.

MadRhino - With your high power bicycle wheel setup, you go full power from standstill and have no issues. What are you using for the rim, tube and tire?

Chalo - 52-60psi

Motomech - Yeah I am getting pretty heavy.

Yes the tires slip on by hand, no levers. Brand new tube I inflate then deflate, put tire half on, insert tube, triple check the tube with tire half on, inflate a little bit and check again. Then as always slip the other half of the tire on by hand, no levers.

I also checked the rim.

Belt spray this time, m.e.c. didnt have Slime anything.

Today on my commuter bike

65mm 24’’ single wall rim purchased 15 month ago from Classic Cycle.
Kenda DH tube that had survived 4 tires no flat since march
24X3.0 Duro Wildlife Leopard tire, fresh, should last the winter.

Rim band is made from the previous DH tube and electric tape.

markz said:

52-60psi

Click to expand...

There is no way that's slipping on the rim, then. This is a puzzle.

For what it's worth, I've gotten to the point that probably three out of four puncture I get are the result of flaws in the tubes rather than sharps or pinches. Tubes really have gotten steadily crappier (and cheaper, in relative terms) during the 30+ years I've been buying them. Your photo doesn't look like any of the tube-related failures I've had, though.

Yup minimum pressure has always been just above 50psi, knowing the max was 60psi on bike tires. I am, from now on, inflating to the 60psi max.

I tell you the reason I thought of tire slippage is because my Townie tire, just slid on and off effortlessly with my pinky slipping the bead over the rim, while the Schwalbe tire I put on just now, needed actual effort (two thumb pressure, if that makes sense) to slip the last bit over the rim to seat it.

If the bicycle tubes have gotten that much worse, then in my case thats one more bullet point for the "Pro's" column of going heavy weight motorcycle rim, tire on heavy weight mxus 3k motor. Which I am sold on.

Closely inspect your tire for flaws in the casing. There's something about the hole in the photo that looks nibbled.