37c blowouts
 

Hi,
I keep getting front tire blowouts and need recommendation:

• My weight: 195 lbs
• Bike weight: 25 lbs
• Tires: 700x37c
• Bike: Scott Sub 10 (Urban)

I was told to ride 90-95 psi and I tend to ride aggressive over curbs, etc.

Thanks

What Brand and model of tire?

Stock tires? If so, I think that's your problem. I've had endless troubles with Continentals and blowouts in the past...even when pumped up to the nominal pressure. You may want to reduce the pressure by about 10% which has worked in the past for me.

That said, you may also want to assess your riding style. I ride aggressively as well but even if I go off a curb or go up a curb, I do as much as possible to reduce the load on the wheels before impact. I don't know much about your riding style but if you are just slamming the wheel into the curb or just dropping it off the curb, that can put a lot of force on the tire.

Try lifting the front wheel up the curb (push down on the tire first then rock back to pop the wheel into the air) and then rocking forward and lifting the rear wheel with your feet on the pedals. It's easier to do if you have clipless but if you have platforms, you can still lift the rear wheel by rotating your wrists forward and moving your center of gravity forward at the same time.

When you go down a curb, rock back as the front wheel goes off and then rock forward as rear wheel goes off. This takes a lot of force on the wheels.

As for tires, I've had very good luck with Vittoria tires. The Voyager Hyper is a very nice tire for urban riding. Be aware that it runs much bigger than the size they list. A "35" mm tire is actually 37mm wide. It even says that on the casing.

Thanks for the input, I try to approach and "land" as 50/50 as possible to reduce the loads. It's been really hot here in Dallas lately (mid-90's+) would you increase/decrease from that?

Continental Sport II

I guess it's tire week in the commuting forum!

Sorry, is there a better thread I should put this on? I searched "tire" on the Bike Forums page and didn't see anything specific to it.

Don't worry, you're fine

You posted on The Best Place.

What's the pressure recommendation on the tire sidewall? 95psi sounds pretty high for a tire that's 37mm wide. But it's not so high that I'd expect blowouts to result. Nevertheless, some tire & rim combinations are looser than others and more prone to such problems.

I'm not an expert, but a few ideas popped in my head. I (also) think 95psi is high for 700x37 tires. I fill my 700x32s to only 85, and when they start to feel a little mushy, they're down around 65. On my old road bike, if I fill beyond 85psi, the front tire rubs the top of the fork. Any sort of heavy bump like a pothole or curb may bulge the tire up at the top and cause a blowout there. But your Scott Sub 10 doesn't look to have that issue. (It's a great looking bike and looks perfect for commuting!)

Another thought is that the Continental Sport IIs are just not tough enough. They may have too much compliance in the sidewall, and the tread may not be stiff enough. I don't mean you should get MTB Bike tires with aggeessive tread, but more robust road tires.

Of course I'm assuming that when you say "blow out" you mean the "Bang! PFweee!" kind. What do the innertubes look like afterwards? is it a tear, or a hole or something else?

It could also be that the rubber strip over the spoke crowns is not thick enough, and that the spokes are poking the innertube, especially when you're running such high PSI.

And finally, I also agree that there may be some funky relationship between the rim and the tire bead. I've had tires that are tight, and others that sit a little looser.

Stop doing this...

Could you describe what you mean by "blowout" ?
Some people use that term to describe plain old punctures.
If you're actually getting an explosive kind of experience, that's a different problem.

I would maybe try some kind of Schwalbe. People seem to have good experiences with them. I have had no issues with Kendas and CST Tires.

Where are you finding the leaks in your tubes? If you're getting pinch flats, that's probably from riding over curbs and such, in which case running too much pressure isn't your problem. Are you getting punctures from road debris? In that case, you might want a tire with some puncture protection features, such as Continental Gatorskins or Schwalbe Marathons (though those specific tires may not be appropriate for your bike for other reasons). Are you getting leaks around the valve stem? If so, a different tire probably won't help, and your riding style isn't to blame, but you need to look at how you're mounting tubes and inflating them.

Max. pressure is 90 and I was told I'd be fine at 92 where my pump is set at.

The last three have been tube pinches, the guy at the bike shop didn't have any other recommendations but was more of the perspective of "that's just the way of the road".
I'll certainly look at a different tire next time but the original is still going strong on the back and the front is near new.

Touche, wise guy...
"Doctor, it hurts when I do this..."
"Then don't do it."

Thanks, I'll do some research on those.
Granted, the streets I ride aren't pristine, but their may be a better option then the Continentals.

Thanks, I live real close to a shop and just drop it off to have the experienced bike smith work on it. The tire got a clean bill of health and the tube was indeed a pinch flat. I was told running at the max. pressure (90) would be fine and I'm set up for that. I go up to 92 the majority of the time because I'd say I'm a slightly heavier rider at 195-200 lbs.
I've gone through a slew of different types of flats and would like to think I know what to look for on the road but brown glass tends to be a sneaky culprit. Going at a good pace I stay away from direct hits to curbs and such because otherwise I'd get tossed anyway.

Yeah, you certainly could get pinch flats from riding over curbs. Someone else posted about techniques for lifting the wheels over obstacles. That's not my area of expertise, but it would help. Higher pressures combat pinch flats, but you're about as high as you can go with your current set-up. Stiffer sidewalls might help, but I don't know what tires have stiffer sidewalls.

Also, I've had good luck with Vittoria Randonneurs, Continental Tour Rides, and Schwalbe Marathons, but I run skinnier tires than you, and my flats were almost always punctures from road debris, not pinch flats.

Thanks for all the replies everyone. It seems that I need to 1.) keep the tires full B.) pay closer attention to potential debris; and lastly, when it comes time, find tougher tires. The Continental's have a nice handle vs. speed feel to me but I'm willing to sacrifice a little of that for durability.

This sounds like the problem is entirely due to the style of riding. If you are getting pinch flats, they likely occur when you ride up over a square curb or other sharp surface and the tube is punctured by the edge of the rim. Normally, if you can't avoid these events, you could minimize them by inflating your tires more. But since you are already inflated to the max pressure, this won't help (and you are in danger of blowing the tire off the rim).

My advice is to learn how to ride to avoid these pinch flat situations, it isn't that hard but you do have to pay attention. Failing that, you could switch to tubeless tires which are more forgiving in this situation.

You're probably right, however, with the uneven pavement and frankly my desire to ride standing it'll be hard for me to change even though I know it puts more than the average amount of pressure on the front tire. Like I said, I avoid direct impacts to both tires by hopping but i'm sure the incessant landing from sidewalks on the tires at high pressure doesn't help. I just didn't think I rode that differently to have this issue so often.
I'll check out the tubeless, too.