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Flat Tires, Cuts, Glass Punctures

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Flat Tires, Cuts, Glass Punctures

Old 09-02-19, 07:53 PM
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Flat Tires, Cuts, Glass Punctures

This year has been horrendous on my road bike tires! NOT including flats, I have ruined four Specialized Armadillo tires due to road cuts from glass etc. I run 120 psi on the rear and 110 psi on the front. All the tire problems have been on the rear. Could the problem be too high of pressure, or is it just the trash on the roads. I weigh 140 lbs so maybe 120 lbs is too much? I'm grasping at straws for a solution. I hate flats!!!
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Old 09-02-19, 09:31 PM
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Some folks insist higher pressure helps resist flats. I haven't noticed any difference in punctures and cuts whether I'm running tires near the maximum or minimum pressures.

Some roads are just too rough and debris-strewn for most bike tires. That's why my errand bike has Michelin Protek Cross Max. Thickest, most puncture resistant and cut resistant tires I could find that aren't solid non-pneumatic rubber. Thick chevron tread and 5mm Aramid puncture layer. I've plucked out glass, radial tire wires, even staples and small nails and screws that penetrated the tread but didn't penetrate the puncture shield to flatten the tube. The Specialized Armadillo hybrid tires on that bike were too prone to flats. The Michelins don't ride badly either for thick, heavy tires.

With my road bikes I'm just extra cautious to avoid debris. Often that means taking the lane where I know there's too much debris on the shoulder or right edge to be safe. It's not just a matter of my convenience but safety -- a flat on some roads could endanger me more than taking the lane and having a vehicle wait for, oh, maybe a few seconds. And I'm careful to avoid some roads during peak traffic hours so there's less conflict.

On my road bikes I've used Vittoria Zaffiro, Schwalbe One V-Guards, some version of Specialized Armadillos for road bikes, Continental Ultra Sport II and Conti Grand Prix Classic. The Conti tires have been the most puncture resistant, most durable, least prone to cuts and best rolling and best riding tires. There are significant differences in tires.

I know several folks who use Gatorskins for everyday road bike tires but I'm not going that route as long as the Ultra Sport II tires work just as well for me and cost a fraction of the price for Gatorskins.
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Old 09-02-19, 09:59 PM
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I read some reviews, & a number of folks seems to get flats with those tires well beyond their supposed design.

At your weight, there is no reason to run hard tires at high pressure- sounds painful.

IMO, tires at high pressure puncture and especially cut more. Think of a balloon- when partly inflated you can poke it with something sharp,

but the same when fully inflated will pop the balloon instantly. Same with webbing- when slack you can saw at it with a knife, but under tension

just a touch of a sharp blade will cause it to fail. Don't have refs to back this up but fits with my experience.

As canklecat says above, where & how you ride makes a difference. Some folks ride through debris-filled shoulders as if they had solid rubber tires. Ride in the roadway.

Finally, inspecting tires post ride, removing embedded bits, and filling cuts with shoe goo is worthwhile. Some flats come from things working their way in over time.
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Old 09-03-19, 10:42 AM
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The problem with Armadillo tires is that the casing is so rigid that you really need to keep them pumped up close to the max or they feel like carp. I used 700x23 All-Condition Armadillos years ago and only ever got one flat - but whatever I hit that caused it put a clean 2cm slice right through the tire and tube. A razor blade? Large piece of glass? I don't know,.. but I don't think any tire in existence would have withstood that damage.

I get very few flats now, but that is likely because I live in a town with not a lot of debris on the side of the road. I did a long tour last year and found flats were much more common in larger cities. I wound up changing tires mid tour (to Specialized BlackBelt) and only got one more flat.
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Old 09-04-19, 04:08 AM
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You are definitely running higher pressure than you need and my experience has been that both too low and too high pressure lead to more flats. Different types of flatting, but same end effect.

I run 80 psi on 32mm tires (up from 28mm previously) on my road bike, lowering the tire pressure from 90 to 80 seemed to help. I weigh 225 lbs, so there is a lot of weight sq in of tire - I think increasing the tire size and lowering the pressure helps both flatting and comfort and all the science these days shows that at typical riding speeds on real roads (vs. dynamometer cylinders) the rolling resistance does not go up. If you are racing, maybe a different story.

One thing I do that I think caused the biggest decrease in flats: after every ride I inspect the tires and remove any chips that I have picked up. I think a lot of times you get a flat the next ride after you first picked up the invader! If I see any deep gouges I'll squirt some Shoo Goo in there, too.
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Old 09-04-19, 05:20 AM
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I think your tire pressure is way too high. I use the linked to graph to pressure tires. I'm 155 lbs. riding on 28mm tires and use 60 psi. https://www.google.com/imgres?imgurl...DYAyUQ9QEILjAA There are numerous other graphs you can google also. Like jpescatore in post #5 , I inspect tire for embedded glass or other flat producing trash frequently.

Armadillos are a harsh riding tire. I'm using Specialized S-Works Turbo and one S=works Turbo Pro. These have proven long wearing and provide a comfortable ride.
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Old 09-04-19, 09:51 AM
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Originally Posted by FrodoBaggins
This year has been horrendous on my road bike tires! NOT including flats, I have ruined four Specialized Armadillo tires due to road cuts from glass etc. I run 120 psi on the rear and 110 psi on the front. All the tire problems have been on the rear. More the problem be too high of pressure, or is it just the trash on the roads. I weigh 140 lbs so maybe 120 lbs is too much? I'm grasping at straws for a solution. I hate flats!!!
To determine a reasonable tire pressure you need to consider the total weight of bike, gear and rider and tire size. Then stay as close to minimum recommended pressure as you can without over flexing the tires. Just look down while riding. The contact patch should not appear overly ballooned. I am not a fan of very low tire pressures as they increase the possibility of pinch flats. And as others have posted, high pressure in tires means a harsh ride and the possibility of more puncture flats. And we should all know by now that high pressure is not the most efficient either. Experiment to find the happy medium for your preferred tire.

If you continue to ride where where there is a lot of road debri, road hazards and poor roads expect flats.

But as others have posted be vigilant as you ride to avoid the worst of it and inspect, clean and repair tires after EVERY ride as part of your post ride inspection and maintenance.

Armadillos are really tough, long lasting tires. You can try to supplement them with heavy thorn resistant inner tubes. However, that will make your ride even harsher. But we canít always control the local riding conditions. Do what you feel is right for your peace of mind.

Personally, Iíve found that Specialized Roubaix Pro tires in 25/28 with Challenge latex inner tubes pumped to 85 psi roll smooth, handle well, and hold up to road hazards well. My total riding weight (bike, me and gear) is usually around 170-175. But I zig and zag to avoid hazards.

In my experience, latex inner tubes increase the performance of any tire, offer a smoother ride, and are less prone to pinch flats and punctures due to their increased flexibility. But, they are more difficult to install without twisting or pinching and do not hold air well. You need to check tire pressure before every ride.

Hope you find find a solution that works for you. Good luck and happy cycling!

Last edited by Sapperc; 09-04-19 at 10:02 AM.
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Old 09-05-19, 09:31 AM
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120psi is WAY too much for a 25mm tire at 140lbs.

Armadillos feel like crap, yes, but overinflating them so that they are rock hard and canít do their job anymore is not the solution. I used to run 90-100 psi in my 25mm gatorskins at 140lbs body weight. Then I got 25mm p zero tires, and realized that I could drop the pressure quite a bit to get some extra comfort. 80? 70? 60? 50?? 40????

Iíve run my front tire as low as 35psi where the only issue is that I start slamming my rim on potholes. These days though, I run 45F, 55R. If Iím riding smoother roads or want a bit of extra responsiveness, Iíll go 50F,60R.

Obviously, you donít have to go that low. But you need to go much lower than you currently do. Your tires are rock hard right now. Imagine trying to poke a block of wood vs a loaf of bread. The tire needs to be able to deform around things to keep them from getting in.

I never flatted even one time on my gatorskins over the course of a year, despite wantonly riding over glass. Now I use race tires with Orange sealant, and while I try to avoid glass, it is impossible around these parts - and I have yet to puncture due to glass. Persistent goathead thorns? Sharp gravel? Sure. But not glass.
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Old 09-05-19, 07:42 PM
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Thanks to all your insights! I'll lower my pressure for tomorrows ride!
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Old 09-06-19, 02:08 PM
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Old 09-06-19, 10:55 PM
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Even if youíre on 23mm tires, thatís way more pressure than Iíd run at your weight. More like 75/95.
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