So, I’m commuting to work by bicycle, rather than riding the bus, or trying to – much healthier, more fun and faster in the mornings! But my bike is giving me fits with the flats. I’ve had about four in the last week or so, all on the same tire (rear). Obviously, the problem isn’t simple bad luck with that many flats.
Several theories I’ve come across:
It’s the spokes. That would account for the consistent flats in the same tire. Problem is, I’ve been able to locate the punctures on my inner tubes, and they’re on the opposite side from the valve stem. If the spokes were puncturing the tires from the inside, you’d have to figure the holes would be on the same side as the valve stem.
The’re compression flats. I’m riding an old Ross touring bike with 1 1/8 inch tires. The tire tread itself is fairly new purchased just a month or two ago when the original tires went bald. What I’ve got on there now is a standard street tire. But I’m overweight, and when you’re well over 6 feet tall AND overweight, that’s a lot of weight to put on a 1 1/8" wide tire. If this is the problem, I don’t know of a solution other than getting a new bike, since the frame on this bike won’t accommodate larger tires.
The smaller tire size and the street riding I do (I ride streets in the monring, sidewalks in the afternoon, please don’t get into the streets vs. sidewalks debate, it’s my life that’s at stake here not yours and nothing you can say will convince me – start a new thread if you like) are the problem, and better quality tires, like the ones made with Kevlar, will help.
This could work. Anyone have any experience with Kevlar inner tubes/tires, etc.? Do they help?
For the record, I’ve carefully inspected the inside and outside of the tire during the changes of inner tube I’ve done so much of lately and I’ve seen no evidence of punctures, shards of glass, bits of wires, nails or whatnot that could be causing the problem. I also put in fresh tire rim liner tape just in case. (Figured it couldn’t hurt) and looked for spoke heads that might be shredding tire. Found none.
So far I’m thinking I might go the Kevlar tire route and see how that works. If not, getting a used mountain bike/street bike combo might be the way to go, since my son is riding that kind of bike to school and it has been totally reliable. (Obviously, the thing to do is trade bikes with my son, but I don’t think he’s gonna go for that.)
For the record, I really like my Ross bike and would like to keep it if I can.
Anybody got any ideas what might be happening here?
If they are compression flats, my guess is that your wheel is out of round or the spokes are out of adjustment. If that side of the rim is out of adjustment, a higher amount of pressure goes through the tube, and there ya go. That said, once you buy kevlar, you never go back. They cost a little over twice as much, but think of it this way, look at the price of gas Any investment in the bike can be rationalized when it’s for commuting.
And I ride on the sidewalk on a couple blocks of my commute because I know those spots are dangerous. If you commute, you know where the dangerous spots are, and screw anyone that tries to tell you otherwise.
If they are compression flats (AKA pinch flats, AKA snakebites) then you need to be running higher air pressure, wider tires, or both. Kevlar tires, strips, or slime won’t help.
When bicycle makers construct taller frames, they normally keep the chain stays the same length. This ends up putting a tall rider nearly over the rear axle, which greatly increases the load on the rear wheel…same as if you run a tall seat post in a smaller frame. You are not getting flats on the front because it is carrying only about half as much load.
Agreed. Pump it up to the maximum rated pressure (should be marked on the tire), and check the pressure at least every other day.
Also, compression flats happen when a tire goes over an irregularity on the road, especially a ridge-shaped one (e.g. edge of a curb, or edge of a pothole). Just be careful to avoid such obstacles, or take them very slowly.
If you still get a flat, note the location of the hole in the tube, and examine the exact spot on the tire (or rim) that corresponds to the hole. Otherwise it can be very hard to find a tiny piece of wire or glass shard that may be embedded in the tire. Also try to take note of what you were doing exactly when it happened.
Pump up the tyres really hard. Then pump them up some more. You want them really rock hard - as well as helping to prevent compression flats it will also greatly reduce the rolling resistance. You can pump bike tyres up a lot harder than you think - 80-90psi is a typical upper limit, but do check the rating on your tyres.
(NB a good way to identify compression v puncture flats is that compression flats often show two holes side by side, hence the “snakebite” name.)
Slime-filled tubes are good, too. I commute to work every day, 9 miles each way, over cobblestones part of the way and a mile of off-road some days, and I have not had a single puncture since I bought new tubes six months ago. (Touch wood!)
I put a Kevlar-belted tyre on the rear, as it needed replacing, but the front is still a several-year-old bog standard mountain-bike tyre. The rear tyre I chose was a Continental TravelContact - mine is a 26 x 2in width but I think they make them in several other sizes.
It’s all about pressure.
Talk to the bike shop where you bought the tires, and ask them for pressure recommendations.
Use a floor pump with a gauge to inflate your tires. If you are using a hand pump you probably are not getting the pressure near high enough.
On my road bike, I run Michelin tires at 120 PSI and my LBS told me I could go higher if I wished.
I am also a very heavy guy, and I don’t think I have ever gotten a pinch flat.
I weigh about 220, and I run the thinest lightest 1" tires I could find on my bike and rarely get flats. Good suggestions so far, are you sure you have the right size inner tube? And I always run near the max pressure. Also, keep you eyes on the road, there’s a lot of debri you need to avoid.
Does the tire suddenly go flat all at once? Does it usually happen immediately after you ride over a curb or similar obstacle? Is the puncture in the tube a slit (or two) rather than a hole?
Those would be signs of compression flats.
As said previously, the cure for compression flats is higher pressure. Also being sure you’ve got the right size tube, and that the tube is seated correctly in the tire. (Nothing beats having a second pinch flat because the tube was placed wrong when fixing the first. Especially out on the trail in gawdawful weather. Not that I’d do something that stupid or anything.)
Unless your tire is low, the sudden rash of flats sounds more like something in the tire than pinch flats, though.
If it’s not a compression flat, follow scr4’s advice on checking for a tiny something in the tire that’s causing the problem. Use your fingers as well as your eyes - I’ve flatted repeatedly because I couldn’t see the whatever and only found it when I felt around in the exact spot of the puncture.
Slime tubes and Kevlar strips or tires will help with punctures.
As always, a good option is to go to your local bike store. They can help you identify the cause of the flat (they’ll know a pinch flat from a puncture on sight), help you look at tire and tube options, etc.
Has it been damp when you’ve been riding lately? A bit of debris or a goat head thorn will stick to a wet tire, and then repeated revolutions will drive it deep into the rubber. I finally learned to avoid any and all puddles and dampness when road riding after a rash of flats one spring.
this past summer, I went through a period where I was getting at least one flat/week, and I don’t commute (just a couple of short rides and one long ride every week), if not more.
While some were clearly attributable to bad luck (stupid tacks in the road), a couple were due to a piece of glass that I (and at least one bike shop guy) missed, and some were most likely that the wheel needed truing.
And for roadside repairs I recommend the Topeak Road Morph pump. It’s no heavier than your typical portable pump, but it’s actually a floor pump (i.e. the pump doesn’t attach directly to the tire valve, there’s an air hose that connects them). And it has a built-in gauge, and it can easily pump up to 120 psi.
Not only are they heavy, but I hear they don’t absorb road shock very well. Which means they are uncomfortable, and hard on the rim. Needless to say, a warped wheel or dented rim is much harder to fix than a flat tire.
I’m not a fan of slime either. If you get flat too big for the slime to handle, I don’t believe you can patch the tube with the slime oozing out of the hole. And the weight of the slime is noticeable.
If your flats are caused by road debris (e.g. goathead throns), a kevlar-belted tire or tire liner may help. That is, they are supposed to help, but YMMV.
Thanks for all the great suggestions. Y’know, solid tubes may be the way to go for me. I don’t mind the extra weight, really – I’ve got quite a way to go before the weight of the bike is an issue.
The flats typically don’t occur all of a sudden (although the most recent one did, while I was climbing a long, steep hill on the sidewalk). I haven’t been taking the pressure of my tires, just pumping them up until it’s difficult to press them inward with my thumb. I’ve got a pressure gauge, I’ll try taking the pressure up to 90 psi and see what happens.
I’ve got a tall frame and a raised seat post, so, yeah, I’m carrying a lot of weight on the rear tire.
Then I would predict that they’re underinflated; also, don’t underestimate the effect a small abount of weight change will have on the bike when it’s on the tires. Gyroscopic effects can really impact the feel of the bike and tires are the most important component of it.
Sounds like they’re underinflated. It shouldn’t be difficult, it should be impossible. (And once it’s impossible, pump it up a bit more for good measure!)
I definitely wouldn’t recommend solid tyres - I’ve never tried them myself but they’re meant to be pretty terrible. Remember, a pneumatic tyre uses all the air in the tube to cushion the shock. A solid tyre can only use the small contact-patch to do the same.
Check the rim tape. It’s the cloth tape or rubber band that goes around the rim and covers the holes where the spokes attach. If it’s worn too thin, or dimpled too much, or slipped to one side, the sharp edge of the holes punched through the rim for the spokes can pinch or cut the tire.
Also, when you replace the tube, have you looked for the hole like scr4 suggested? I’ve found the most effective way to be pumping the tube way up after removing it from the tire and rim, then putting a little water on the tube. If the hole’s on the inside of the circle, it’s most likely a rim tape problem. If the hole’s on the outside, it’s probably a puncture. If it’s two holes side by side on opposite edges, it’s most likely snakebite. Which isn’t really snakes; it just means that the tire pressure is too low, and the tube got pinched between the ground and the rim. And finally, if it’s only on one side, but kind of elongated, it probably means the tube got pinched during installation.
To update: I got a Kevlar tire with a steel belted lining. I also bought some slime sealant. I put in a new inner tube with slime sealant and put the Kevlar tire over that yesterday. I’ve ridden it a couple of times since, so far so good as they say.
As for the under-inflation, I can only get the tire up to about 50 psi on my floor pump, even though the tire is rated for 90 psi. When it gets up to 50 psi, I hear air escaping from somewhere and the pump gets very resistant. I’m afraid of blowing out a valve or something if I push harder (frex, with my hand pump, if the pressure gets too great the handle section just gets pushed right out by the air pressure and I have to screw it back in. Doesn’t damage the pump, but does impose a limit.
I’ll go to a service station and use their pump to get it up to 90 psi.
I’ll keep you posted if anything flat happens (or doesn’t) in the next week.
Any investment in the bike can be rationalized when it’s for commuting.