General Cycling Discussion - Flat Tire Problem on 1981 "Racer" bike

I am not a bike fan, but instead as my username suggests I am a Model T Fan. For you that don't know what a Model T is, it's an automobile produced from 1908 to 1927 by Ford Motor Company.

I do ride my bike to get exercise. It's a 1981 Free Spirit "Pinnacle" bike. I've been told it's a racing bike, which I guess is the same as a road bike. It has those weird handlebars that I still don't understand and can't get used to.

Anyways I've had problems with the rear tire. When I bought the bike at a garage sale in 2011 and got it for $20, it was in good condition. However, it wasn't a month before I got a flat tire on the front tire and the original 1981 tire/tube in the front had to be changed out. He also changed the 1981 tube in the rear tire also, but didn't change the tire.

The tire lasted until this year when it finally gave up the ghost and almost blown up on my adding air into it. It didn't pop, but the tire and tube was changed to a weird Chinese Tire brand.

Anyways it wasn't a week until the 1st Chinese Tire got a hole in the outer tire and the tube went through it. Even though this sounds like a stupid reason to puncture a tube, I grabbed a sharp paper clip near me and popped the tire. I didn't want it popping.

That tire/tube was changed to another Chinese Garbage Tire. It's been pretty good up until now. Today it was a little low and decided to go over to a friend's house to put air in it (I don't have a pump or air compressor.) I put the recommended 90 pounds in it, and visited with my friend for a few hours until I got back on it.

When I got back on it, I got about two blocks before I suddenly heard a big "BANG!" I was riding my bike down a hill on the sidewalk (the street is dangerous where it popped, so I ride on the sidewalk.) It scared me, but wasn't all that loud and it sounded like those guns they shoot to signal runners to run. I looked down to these kids down the hill from where it happened and they were looking at me. I then knew it wasn't a gun, but thought my tire got punctured.

It got more than a puncture. It had a blowout. You can tell that the tube pushed the tire out and the tube got stuck between the tire and the rim. You could also see the big split in the tube clear as day.

Before I left my friend's house, I made sure that nothing was wrong and that everything was alright and nothing was pinched. Everything checked out fine at his house. I know I put 90 pounds in there because the pump had a gauge on it that said it had 90 pounds. I know there was nothing wrong in the sidewalk/road because my front tire didn't pop.

I didn't see what the tire/tube looked like before it blew. However, I can see where it pushed the tire out and got pinched.

I have a question. I just put air into the tire a few hours before this happens. Nothing's wrong and the tube's not pinched. What could and did go wrong? It also had a little below the maximum tire pressure, which was 90 PSI. I had between 87 and 90 PSI in that tube.

However, when I did see the tube, the tube was bent in like a "V" shape where the valve stem is. But how would this cause a problem?

Also, the guy who installed this is named Chuck and he works in Boonville, Missouri. I personally don't recommend him. The tire's and tubes he's put in it hasn't lasted a year! :twitchy:


Please help! I will get another dude to install the tubes or may install the next ones myself. I will get photos tomorrow.

Most of the time blowouts with the loud bang are caused by the tube being pinched between the tirebead and the rim.

It sometimes happens to most of us.

This bang wasn't really loud, but enough to scare me and the kids down the hill.

The tube wasn't pinched. I made sure of that because a couple years ago my grandpa was inflating a 40 PSI tire and the tube got pinched and it popped.

Like I said, I'm a Model T Fan. Model T's have the same type of tires (clincher/beaded edge) as a bike and a Model T Tire requires a tube. Model T's have the same tire/tube design but bigger.

Post a pic of the tube.

I will tomorrow.

The tube is a Kenda. I personally dislike Kenda, all made in China. All Kenda makes that's good is bike tires, but the worst tubes.

The tube split down the middle, right on the seam. What would cause a blowout?

This is one blew out on my front wheel at 17 mph.
Loudest bag I ever heard.

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I wasn't going really fast.

I however was going a good 10 miles per hour. This bike has seen a lot of use. I sometimes go up to 15 miles on this bike daily some weeks.

The tube however, like I said, was bent in a "V" shape at the Valve Stem?

Also, what brand of Tube/Tire do you recommend to use? I'll get photos tomorrow.

Any ideas on what caused the blowout?

It is always possible that the tube was faulty. It's more likely that you failed to install it properly and trapped the tube between the tyre and the rim. This can be done without being obvious.

If one owns a bike, one should own a bicycle pump. It's ridiculous to have to go to a friend's house every time a tyre needs inflating,

I doubt very much, from your account, that you'd want to follow any recommendation I would make for tyres, because I'd likely pay twice as much per tyre as you paid for the bike. But if you tell us the size of the wheels you are using I'll, give it a go.

In my experience this problem (if it is recurring) usually indicates a problem with the rim itself, not the tires or tubes. Does the rim have any "blips" in it or other signs of damage?

I once had what looked like an ok rim, but the tire wouldn't seat properly and the tube would bulge out and blow even at half of the max pressure indicated on the tire. Despite everything seeming straight and true, I replaced the rim and the problem went away. I kept the same tires, and same brand of tubes.

Also for others in this thread, since it is a Free Spirit it likely has 27" wheels. I have noticed a problem lately with tubes in this size actually being too big for the wheel so that they bunch up when inflated which can also lead to leaks, but not to blow outs that I know of.

Does the bike have steel or alloy rims, are they hook edge or smooth edge rims? If smooth edge a higher pressure tire is not going to stay seated above about 70psi. Pictures of the rims wouldn't hurt. It is very easy for a tube to puncture due to roughness on the rim too.

Aaron :)

Flats happen. All roadies know and accept this.

If you are experiencing multiple flats before you get to the end of your street, then you have a problem. Otherwise....choose a tire and tube of your liking and install it.

Kinda like Model T's, isnt it?? :D

(what you experienced on the blowout is a lifting of the tire bead from too much pressure or a weakness of the tire bead/rim clinch. you dont need to inflate to 90 if that is the max psi)

Does the bike have steel or alloy rims, are they hook edge or smooth edge rims? If smooth edge a higher pressure tire is not going to stay seated above about 70psi. Pictures of the rims wouldn't hurt. It is very easy for a tube to puncture due to roughness on the rim too.

Aaron :)

Exactly. Old steel rims can't take the high psi. - 70psi max.

Does the bike have steel or alloy rims, are they hook edge or smooth edge rims? If smooth edge a higher pressure tire is not going to stay seated above about 70psi. Pictures of the rims wouldn't hurt. It is very easy for a tube to puncture due to roughness on the rim too.

Aaron :)

Yup, my thoughts too. Those old steel wheels were not meant for high pressure tires.

The tube split down the middle, right on the seam. What would cause a blowout?

That's from a pinched tube. or a tire that fits too loose on the bead. Either way, the tube was not supported by the tire. Tubes by themselves cannot hold 90 pounds of pressure; they need the tire's cords for strength.

Edit: after reading subsequent responses, yes the rim might have something to do with it. Steel rims had a 'rolled' bead which doesn't hold the tire as tightly as the modern hook-bead that modern aluminum alloy rims have. Tires used to have a warning molded right into the sidewall, "use with hook-bead rims only." My old 1973 Raleigh Record had steel rims, and it could only take 65 psi.

I got some photos today.

It's likely that it came from a pinched tube, but it is possible as I just pumped up the tire about an hour or two before it happened.

The tube is a Kenda. The rim is a clincher/beaded edge. Will post photos later.

The image below is of the tire itself.
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Where my finger is located is where the split in the tube is.
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The split in the tube.
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The Kenda logo along with the serial number.
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The Kenda Logo w/ SN.
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The bike itself.
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The tube out of the bike tire.
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The tube out of the bike tire and the Schrader Valve.
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Blurry image trying to get a picture of where the tire buldged.
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Click on a image to view a bigger image.

It's not the tube's fault. Most likely the bead lifted off the rim due to over inflation. Many have discovered that you can run a 12.00 tire and a 3.00 tube just like you can ultra expensive ones.

I doubt overinflation. The tire had 90 PSI in it, which is the maximum pressure.

If it was overinflated, why didn't it pop within those two hours I was at my friends house?

Just because the tire has a 90psi max inflation pressure doesn't mean that it will stay on an older steel rim - is that a steel rim?

Lots of decent tires/tubes and other bike parts are made in China, by the way.

I have to inflate it to 90 PSI because the front tire has 70 PSI and it's uncomfortable riding with a front tire having more air than the rear.

In order to do this comfortably, I would have to have the rear at 70 and the front at about 45 PSI. IDK about 45, but I have a feeling that the tire would be flat with that.

50 and 70 wouldn't work.

My last tire that was original to the bike had 75 in the rear and 70 in the front. I think I'll do that next time. 70 in front, 75 in rear.

judging by the shinyness of the photos, your bike has old steel rims

the modern tire is rated to 90, but the old rims are only rated to 65
you have to go by the Lowest rating for things to work together

as for why didn't they blow out immediatly after inflating but only after 2hours when you rode it? because you weren't riding it yet; weight of rider and the action of rolling was the last straw.

stay at 65psi
it sucks, i know, they feel flat all the time
thats why the design is considered obsolete
you can either live with it or change to modern aluminum hooked rims designed to take higher pressure

Good to know! When I get a replacement tire/tube, I will tell him that.

If he over-inflates it up to the 90 PSI, I'll just deflate it back to 65. I'll let a little air out of my front tire (which has 70) tomorrow. I'll have 60 in my front and 65 in the rear.

Will a little flat tire (65 psi in a 90 PSI tire will probably feel and look flat) hurt any thing?

Good to know! When I get a replacement tire/tube, I will tell him that.

If he over-inflates it up to the 90 PSI, I'll just deflate it back to 65. I'll let a little air out of my front tire (which has 70) tomorrow. I'll have 60 in my front and 65 in the rear.

Will a little flat tire (65 psi in a 90 PSI tire will probably feel and look flat) hurt any thing?

It wont look flat at all. As for the feeling, that depends on how much you ride with the acquired familiarity and are able to tell the difference. At 65psi you will have a comfortable ride.

Only the very high PSI racing tires have a prescribed minimum for safety and performance issues.

So it will be okay if I have 65 PSI in it?

The front tire will be 10 PSI lighter, and the rear will be 25 PSI lighter. I know the front won't look or feel any different really, but the rear is 25 PSI lighter, that's a huge difference!

Lower pressures increase the risk of pinch flats. If you start getting them, you may want to bump up the tire size.

What is a pinch flat?

What is a pinch flat?With tire pressure low, you run over a little rock that you may not have seen to avoid....it happens all the time....the lower pressure will not keep your tire "off" the rock. The rock pushed the tube into the rim harshly and enough to hole it. With adequate pressure you would just ride over top of the rock but the lower pressure hinders that from happening.

So it will be okay if I have 65 PSI in it?

The front tire will be 10 PSI lighter, and the rear will be 25 PSI lighter. I know the front won't look or feel any different really, but the rear is 25 PSI lighter, that's a huge difference!I typically run 10psi more in the back than in the front. Besides the obvious thought of having your hind quarters on the back wheel more, you tend to manuever around rocks and potholes (that's a pinchflat and taco'd rim waiting to happen) with the front so that's why I tend to protect that back wheel with higher psi than the front.

But that's a personal thing.

Sure looks like a "tire done blowed off the rim" situation.

The folded tube situation you mention is likely because you're using tubes made for tires with a bead seat diameter of 622-630 mm but your wheels likely have a BSD of 590 mm , this makes it tough to install a tube without folding it a bit. Check tires to confirm, look for a number like (38-590), or similar.

My Free Spirit that came with 590 wheels fits 622mm (AKA 700c) wheels just fine, pretty close clearance with 28mm tires, but they don't rub. Dunno if you care to blow the dough on some new or used 700c wheels, though.

Looks like biketiresdirect.com stocks proper sized tubes if you'd like to get a tube in there without folding:

http://www.biketiresdirect.com/product/quality-26x1-3-8-schrader-valve-tube

I don't want a taco'd wheel because they are expensive.

So would 70 in rear and 60 in front be okay?

Max pressure will vary by rim. Inspect the bead carefully @ 5 psi intervals after 50psi. It'll usually start creeping up out of the rim in the spot where it's likely to blow off. Sometimes you can deflate again, try to reseat the beads and reinflate. I often have tires blow off a steel rim at, say 60psi, but then deflate and re-inflate to more psi no problemo.

How can I see the bead?

Most tires will have a mold line that kinda divides the bead area from the sidewall area, just look for little hops in that.

The next question is, what size is the tire? Modern tires, meant for hook-bead rims, are pretty skinny; probably skinnier than you should be using on a steel rim.

I don't want a taco'd wheel because they are expensive.

So would 70 in rear and 60 in front be okay?I'd sure hope so. My '79 Motobecane has 27" rims which has the lower pressure rated tires compared to 700c, I run those at 65 front and back. So you are probably in the ballpark.

I guess it's time for an update.

The guy fixed the tube Monday. He said one more flat and he'll blame it on the wheel.

This time, I think he's trying to pull a fast one or he put a defective tube in. It's not completely flat, but yesterday I swore it was full and I couldn't even push down on it, even though it had 70 pounds in it (he took my advice and inflated it to only 70 pounds.) Now I can push down on it, and it doesn't take that much force. Is it just me or is this tire slowly leaking? We'll find out tomorrow.

Yesterday, I deflated the front tire completely and inflated it to 60 pounds. This gives 10 pounds difference between both tires. I have to deflate it completely because if I don't I found out the pressure gauge on the tire pump doesn't go up to say 30 pounds if I had 30 pounds in that tire, it just stays at 0 until you pump it then it goes up to like 2. The front tire's fine. No blowouts yet. Usually it's the front tire to go, but this time since he put the new modern tire on about a month ago the rear has blowouts and punctures every week. Before then, this didn't happen.

The front tire is a Kenda, both the tire and tube. The tube was replaced in March I think, so it's fairly new. It holds air like a charm and hasn't had any problems with it. The tire's from last year when I just bought the bike at the garage sale. It wasn't even a month before I rode over a rock and next thing I hear is a hiss coming from the front tire, good thing it wasn't far from my home. When I did get home, which wasn't even a mile away from the puncture spot, the tire was completely flat. The tube in that tire was the original to the bike, even though I never got to see the tube or the inside of that tire.

Sounds like you might have a pinch flat.

cheap tires on a crummy rim is a recipe for the bead slipping off the rim. Can't tell you how many times I fought that back when your bike was new. Nothing like rushing to let the air out of a tube as the tire bead slips up the rim

It's a pretty slow leak, if there is one at all. I can't hear any hissing or anything, but we'll have to see how it feels tomorrow. If it's flatter I'll have to take it to the bicycle man and have him look it at it.

It's a steel rim, he confirmed that. This tire has been nothing BUT trouble since Day 1.

I doubt overinflation. The tire had 90 PSI in it, which is the maximum pressure.

If it was overinflated, why didn't it pop within those two hours I was at my friends house?

Yo, read what these posters are tell you. It doesn't matter what the tire says...if it's a vintage steel unhooked rim you are limited to like 65-70psi, no matter what tires / tubes you use. Typically, they seem fine when you you first put them on and pressure up to 100psi, 30 minutes into the ride or a cople of hours after you stop BLAM, you get a tire side blow off and and a long slit in the tube. You need new rims, or run low pressure.

It's a pretty slow leak, if there is one at all. I can't hear any hissing or anything, but we'll have to see how it feels tomorrow. If it's flatter I'll have to take it to the bicycle man and have him look it at it.

It's a steel rim, he confirmed that. This tire has been nothing BUT trouble since Day 1.

Do you pay someone to do all the work on your Model T? Changing bicycle tires is simple, finding slow leaks in a tube is simple. Hell I have changed tires on a Model T many a time, it is simple if you have the right tools. FWIW we had two Model T's a 1916 touring car and a 1921 center door sedan with the body by Fisher.

Based on your "evidence" you are getting pinch flats from under inflation, you have cheap steel rims that are notorious for not holding onto tires very well. You will have the same problem with a more expensive tire and tube on the same rim. It is most likely NOT the tire and tube and is not the guy's fault that is changing them for you. Get an air pump and pump the tires up before you ride, bicycle tires and tubes will not hold air pressure indefinitely.

Aaron :)

It's a pretty slow leak, if there is one at all. I can't hear any hissing or anything, but we'll have to see how it feels tomorrow. If it's flatter I'll have to take it to the bicycle man and have him look it at it.

It's a steel rim, he confirmed that. This tire has been nothing BUT trouble since Day 1.For those slow leaks......do you have presta valve tubes or the older schrader valve similar to our cars? The presta is smaller in diameter and has the little screw down lock nut on the valve pin. If you put air in the tube and dont have that valve locked down tight (pulling against the valve for a secure lockdown) you could be losing air.

Just wondering. I cant remember reading in this thread where you'd indicated what kind of valve you use.

After having this much trouble with the old wheels, I know what I'd do: get a new set of cheapie wheels with hook beads. Most bikes with 27" wheels had long-reach caliper brakes, and the brakes can be adjusted for the 700c size. If you choose the right wheels, you can move your existing freewheel and tubes over.

The tube does have a leak. It is flat today when I didn't do anything. BTW, I don't own a Model T, or yet anyways.

This bike has a Schrader Valve. The tube is under-inflated to 70 psi because it has steel rims. This is actually the dude's fault for putting a tire requiring 90 PSI on a Steel Rim when he knew the rim couldn't hold that pressure.

The tube does have a leak. It is flat today when I didn't do anything. BTW, I don't own a Model T, or yet anyways.

This bike has a Schrader Valve. The tube is under-inflated to 70 psi because it has steel rims. This is actually the dude's fault for putting a tire requiring 90 PSI on a Steel Rim when he knew the rim couldn't hold that pressure.

Tires themselves don't "require" any particular pressure -- if they are marked, it's because they have arbitrary maxes (to keep them from blowing off hooked rims) and arbitrary mins (to limit the number of people whining when they get pinch flats).

So, what should I do to prevent having a blowout and prevent having another pinch flat?

So, what should I do to prevent having a blowout and prevent having another pinch flat?

Inflate to 65-70 PSI religiously and if you have another pinch flat, move up a tire size. Once you have good tubes in there, they should hold that pressure for at least a couple of days between pump-ups.

So, what should I do to prevent having a blowout and prevent having another pinch flat?Dont overinflate (blowouts) and dont underinflate (pinch flats). I think you have found good recommendations on this thread, including the one preceeding my post.

Flats, though not an everyday occurence, are part of the bicycling experience. Familiarize yourself with the repair, carry the equipment (tire levers, extra tube, patch kit) and smile brightly the next time you have one while riding.

There's a lot of "stuff" going on here. Hook bead, not hook bead? Steel rim, aluminum rim? Was the inner tube actually properly installed? I've been messing with bikes for a long time and I don't know the answers to any of those questions for sure.

For $5.00 or $10.00 a local bike shop will be able to see the bike and answer all of those questions. Then you'll be working with facts rather than guesses.