If you are launching off curbs and actually catching air, landing equally will help but also try to land with flexed arms and legs. This is your best "suspension" even on fully suspended bikes. Let your "suspension" soak up the energy and your landings will be softer.

Temperature makes only a marginal difference. If you fill your tires at 70°F with 90 PSI of air and the temperature rises to 90°F, the pressure will increase to 94 PSI. With every other tire I've used, this would be trivial. However, given my past experiences with Continentals that had been filled with 90 PSI (the "recommended" pressure) that have blown off rims, I'm not sure that statement is true. Continentals have bitten me too many times for me to trust them.

I don't think you are over inflating the tires but I do think you misunderstanding terminology. A "blow-out" is when the tube is no longer contained in the tire and expands rapidly to the breaking point. If it is a true "blow-out" you won't even hear a hiss of air as all the air is expelled at once...and loudly.

A "pinch flat" or "snake bite" is when the tire can deflect far enough for the tube to become pinched between the rim and the tire. It is a slower event. I find it a little hard to believe that you could have a pinch flat even if you are landing straight legged off of a curb with 90 PSI in the tires. Even if you were to pancake onto a flat surface from 10 times the height of a normal curb, you'd be hard pressed to pinch flat with that kind of pressure. The tire is going to slip off the rim first and actually "blow-out".

I'm wondering if you really have as much air in the tires as you think you do. Gauges can be inaccurate, although to pinch flat a wide tire like yours, it would have to be off by 20 or 30 PSI.

Check your pressure gauge, try to land "softer" and/or get a bike that is better designed for launching off stuff.

If it really is pinch flats, I cannot picture you doing that launching off the curbs ( I ride off curbs with my Venge and 28s). It is far more likely going up onto the curb and not completely clearing the curb. Neither tire should touch the curb on the way up and over.

is it possible the problem is with your rim? That is thatthere's something sticking out of it that cuts the tire when you put a lot of pressure on one spot? Or is it possiblethatthe joint of the tire is expanding when you ride off of or onto curbs and that joint expansion then "bites" the tube giving it the characteristic snake-bite punctures?

You might want to try this. Ride your bike to one of the curbs you ride up and over but stop at the curb. Get off the bike and push the front wheel har against the curb. look at the deformation of thetire and how much/little tire is left before it bottoms out. i've done that with a number of people's bikes thereby showing them how little air they actually have in their tire.

As others said, technique is critical. You can actually chafe/cut sidewalls of tires by riding up and over curbs on an angle because the tire slides a bit along the curb.

If i ride up over a curb I pull up on the handlebar just as the front wheel touches it and that lifts the front wheel up onto the curb and then when the rear wheel just touches the curb I stand and throw my weight forward thereby lifting the rear wheel up and over the curb too.

Cheers

Very good point made here! Make sure there is not a mechanical problem causing or encouraging these flats.
A small burr on your rim may be enough when you add curb jumping into the mix.

When you say the "last 3 were pinch flats" , how often are they occurring? ...how many miles between flats?
AND, are you saying there were even MORE, just that the last 3 were the same?

Another thought.... what is the quality of the tubes being used? There are good tubes, and not so great tubes out there.

Good luck.

Jumping off curbs, landing from the sidewalks.....are you riding in the street or starring in a stunting video? First thing I would do is change your style of riding. That is the cheapest and probably most efficient thing you can do.

Are you getting random flats or is it when you specifically come off a curb?

And if you would like to continue riding aggressively like you are, I might suggest a mountain bike, as those wheels/tires are far more appropriate for your style of riding.

Check out some Peter Sagan videos . For a road racer he does some crazy stuff and gets away with it. But he's nimble and lands like a cat.

Bunny hop over traffic island, during a race:
Sagan bunny hops over fallen rider at Paris-Roubaix. .

If you weigh 190, and your bike weighs 25, so... counting my fingers here... total weight 215.

Assuming 40% of that's on the front wheel, that's 86 lbs of weight on the front wheel. That's an approximation, of course; the amount of weight on the front wheel will vary depending on terrain, how you're riding, etc.

Now, checking the recommended pressure chart....
http://problemsolversbike.com/files/...ongraph_2.jpeg

It looks to me like 40 psi should be the most comfortable, and most efficient, tire pressure.

Thanks CY, I have had both big pop flats and slow unwinding pinch flats. I have the yellow JoeBlow pump that I guess not too many people are happy with but I agree it'd be hard to be that far off. Is there an easy way to check accuracy of a pump or air pressure on a bike tire like a car tire gauge?

Thanks Miele, I do a manual pinch of the tire before I ride and check the bend when I get on the bike to make sure it doesn't look low. I'd like to say that when I'm riding I clear the front tire 99% of the time and if anything, lean forward when the back wheel needs to ride the curb up when going slowly.

I asked the same but they said no rim issues when they took off the tire and tube.
The flats are occurring between 10 and 50 miles. The pinches are intermittent and just the last couple have been more mysterious (didn't hit anything, uncertain about debris but no real cuts were found).
The tubes are the $18 dollar jobs from the shop.

Yeah, that chart confused me as well.

TenSpeedV2, I'm no NYC messenger but I do like to commute on busy streets and that means a lot of sidewalks and a big reason I got the Sub 10 (hybrid bike) as it was marketed towards that type of riding. https://www.rei.com/product/842600/s...b-10-bike-2013
I'm sure there's been major advances in mountain bikes but I do such little off-road and spent a good amount on this last bike that that option isn't really in the cards.
The flats are not specifics to curbs, I just brought that up as that is where I can think the forces are most present. I don't seek out sidewalks but sometimes it's the safest option.

Assuming that you are using presta, you'll need a gauge that goes on a presta valve. There are any number of them around. Their accuracy isn't that much better than your pump's but you'll have a second data point. If you have a schrader valve, you could use a car tire gauge or get one specifically for bicycles. There are several models of pressure gauge that will do both presta and schrader. I've used a Zefal in the past. They are inexpensive, analogue and have a feature that stops the needle at the pressure so that you can read it off the bike.

Cool, thanks for the info.!

If you are getting pinch flats, maybe consider a tubeless setup? Depends on whether you want to invest some time/money, whether your existing rims & tires are conducive to a conversion etc.

If you have enough money to throw $18 per tube at the bike shop, then you should definitely consider buying a tubeless wheel/tire combination. Consider the up-front cost to be payment for many tubes in advance.

Otherwise, learn to change and/or patch your own damn tubes! It's something all cyclists eventually need to do themselves on the road anyways. Even at LBS-inflated prices of like $6.99/tube, that's a lot of savings.

Will do, I'm sure the $18 is tube and labor. Anyway, challenge accepted.

Yes, that seems like a typical and even fair price for parts and labor, but it's such a fundamental task people that are at all budget conscious should do it themselves.

$18 should buy you a patch kit and 1 or 2 tubes. Stay away from 'glueless' patch kits, they are just stickers, they will get you home, but not last forever. You want a proper patch kit with vulcanizing glue, which chemically bonds the patch to the tube to seal the puncture. Park VP-1 is good, many people speak very highly also of Rema patch kits.

I highly recommend you get a pair of Pedro's tire levers, they're just the best, and only about $5, surprisingly cheap among the landscape of high-priced specialty bike products.

And then for on-the-road repairs you'll need a portable pump to bring on your bike if you don't already have one, that would take you out of the $18 range though.

:lol:

My point precisely! If you understood it, you wouldn't be running 37 mm tires at 90 psi.

I really don't know what you are doing wrong, and I don't mean to lecture you. I get a lot of flat tires (I think the total was 25 for 2015), and the cause is not always clear, but over time you develop strategies for avoiding them as much as possible and dealing with them as efficiently as possible when necessary, and what works for one member of this subforum isn't always the best thing for another. You're going to have to figure this out for yourself.

But if your tires really measure 37 mm, you really don't need to run such high pressure. 40 psi rear and 50 psi front really should be fine. If you carry a lot of weight, you will need higher pressure. If you prefer a bumpier ride for some reason, your tires can handle it, but you won't get any advantage from it in terms of efficiency or flat protection. Indeed, if you prefer a bumpier ride, you might consider thinner tires.

I'm not sure where you are coming up with that number. The chart starts at 30 psi which might be appropriate for 66 lb load on the rear tire. But if for an 86 lb load, the pressure should be around 40 psi. But I think the chart's pressure are far too low for the load they are carrying. At 30 psi or even 40 psi for a narrow tire like a 37mm, the bike would corner poorly because the sidewall would flex too much. And that probably wouldn't provide much protection against impact. In other words, the wheel would be at higher risk for damage during even a marginal impact as well as the tire more prone to snake bites.

Yes, it might provide a comfortable ride but if you are fixing flats all the timeit's not worth the comfort to risk damage to tires, tubes and wheels. Remember that TJohnson is experiencing snake bites at 90 psi, reducing the pressure to 40 psi wouldn't improve his situation.

Personally, I wouldn't run 30 psi in a 55mm mountain bike tire which has a whole lot more volume.

Doh! You are right, I misread the numbers on the left of the chart :innocent: The chart indicates 40 psi front, 50 rear. I will edit my posts.

I agree that riding at that relatively low pressure OP would be at increased risk of pinch flats, so it might be a good idea to go a little higher. I do not mean to advocate something that will get more flats.

90 psi is a lot higher. I cannot diagnose the problem he is having, but 37mm tires at 90 psi should be pretty impervious to pinch flats. I suspect something else is going on.

Riding on the sidewalk is not optimal in most cases. Cyclists should be in the street, as they are traffic, and move much faster than pedestrian traffic that is on the sidewalk.

Stop riding over curbs. Road bikes are not made for that. When you stop doing it, you won't get any more flats from riding over curbs. Your pressure is not your problem, and your tire is not your problem. Your riding is your problem.

Many times I've use a pressure gauge to show people just how low the air pressure in their tires is when they've used the pinch test to check it and figured it was high enough. It'd be interesting to see if your tire pressure isn't in fact lower than what you think it is.

Cheers