High Speed Rear Blowouts

[Blakenstein]

Presta is a HUGE pain in the butt. Generic rulz!

You would not believe how often people are stranded on long bike trips because local chain stores and gas stations only deal with standard automotive type valves. I have come upon "spandex" bikers in distress at the side of the road about a dozen times over last few years and was only able to bail them out half the time because of those oddball valves. Would have had much better score if they used regular valves.

When I travel more than five miles, I carry a spare presta in my pack and 2 adaptors for filling air. all I need is one . I also carry an emergency pump . At home, in my tool box, I have 6 spare presta tubes . Cyclists should not have to deal with gas stations..my bike shop told me that is all their gonna have soon, and I don't blame them. Presta tubes are an incredible muchly needed improvement and I thank God for whoever it was that created the presta.
After typing this I'm going to add another preasta to my pack. Adaptors are only a dollar,-get lots of them.

 

[xlite]

I was mad because the rim was made for presta and I only had normal tubes.
Presta tubes are an amazing advancement and improvement to the wheel world HOWEVER; sometimes it seems that because of the adaptor on the valve, I,m not getting proper reading on the pressure gauge .

Aside from the fact that presta rims don't take "normal" tubes, you have to find and carry special adapters, carry special tubes, they don't work with pressure gauges, and cost more than regular tubes... are there any other "amazing advancements and improvements"?

Seriously though, is there any single advantage over regular tubes?

 

[lovehamr]

From what I understand, presta valves came about for two reasons; #1 was rim sizes were getting more narrow for high performance tires and the size of the schrader valve meant that the hole on the rim would compromise rim strength, this still holds true. Most rims that I see cracked are cracked at the valve stem hole, the larger the hole the weaker the rim all other things being equal. #2 is the positive seal. The only thing that keeps air in a schrader valve is a little spring, with a presta it's a screwed down seal. They don't leak.

As for the verbiage of "normal" or "regular" vs. "special" this is nothing more than semantics. If you ride a high performance bike then you use presta and all of your support gear is set for that valve type. If for some reason you have to use a schrader pump to fill a presta valve the $.99 adapter works fine, yes even with a gauge. It’s no big deal. If you ride a cruiser from China, uh, I mean Walmart, then it’s going to have schraders. But that goes hand in hand with all the other stone-age things that you get with that level of bike; like 1” threaded quill stems instead of 1.125” threadless which are much stronger, or 1 piece cranksets with cup and ball bottom brackets instead of modern large bearing 2 or 3 piece types. You only have to overhaul 1 of each before see the light and get yanked out of the dark ages. The list goes on and on but to many people that doesn’t matter and that’s cool as well. If you don’t use the bike’s crank to do anything more than start the motor then who cares. On the other hand, if you’re going to be using the pedals on a regular basis and plan to stress yourself and your bike, then looking into improvements that have been made in bikes since the 70s will pay off big.
Steve

 

[Blakenstein]

Aside from the fact that presta rims don't take "normal" tubes, you have to find and carry special adapters, carry special tubes, they don't work with pressure gauges, and cost more than regular tubes... are there any other "amazing advancements and improvements"?

Seriously though, is there any single advantage over regular tubes?

The main advantage I like is that the valve stem locks to the rim . From totally deflated,fill up a regular tire, and then fill up a presta.You'll see what I mean-use a hand pump.Another advantage is that I'm sick of getting flats because of "moving valves"!! With presta, this does not happen. Adapters are very common these days and are a dime a dozen. Presta tubes have now become very common also.

Now....here's what I carry in my pack..:multi-head screw driver,spark plug wrench,cone wrench(for outer wheel bearing races),2- 5/32 allen keys,10mm.1/4driv.socket,4mm allen driv.bitt,7/16 flex gear com.wrench,7/16 com. wrench,5/16flex gear,9/16 flex gr.,15mm flex gr.,3/8 fex gr.,6"adjustable,100mm. adj.,5/16 deep socket w/driv.adapter,precision screwdriver,pressure gauge, presta valve adapters,presta tube and emergency pump.
My heart goes out to those of whom have to carry a wee tiny little adapter.

P.S. I'm being lazy!! I've not added Norms cable ends yet to my pack. Oh well, at least I made a couple........................

 

[bairdco]

... You only have to overhaul 1 of each before see the light and get yanked out of the dark ages.
Steve

i like the dark ages. and besides, they've had three piece cranks since the late 1800's. and overhauling an ashtabula type one piece crank is a lot easier and a few hundred dollars cheaper than a new euro bottom bracket. and you only need one wrench.

i'm not arguing, i actually understand and agree with what you're saying about high-end bikes, but nobody's putting motors on 10,000 dollar road bikes. not that i've seen, anyway. and it would be funny if someone did, because they'd end up with a motored bike that's slower than they could pedal.

back to the topic at hand, if you fix that slanted valve stem as soon as you notice it, you'll have no problems. i've never had one just suddenly slip and get cut. it usually takes a few days or weeks of neglect before that happens. it's a 5 minute fix.

 

[lovehamr]

i like the dark ages. and besides, they've had three piece cranks since the late 1800's. and overhauling an ashtabula type one piece crank is a lot easier and a few hundred dollars cheaper than a new euro bottom bracket. and you only need one wrench.

Make that a pedal wrench a large farmer's tool (adjustable wrench) and a screwdriver. Don't really know what you mean by "euro" bottom bracket. But with a cartrige style BB or an even newer outboard bearing BB you do need a wrench for the crank bolts (self extracting) and the BB socket. We can have a crank and BB swap race if you like. And you can get cart. BBs for like $25. Slap it in and forget it, no adjustments at all.

i'm not arguing, i actually understand and agree with what you're saying about high-end bikes, but nobody's putting motors on 10,000 dollar road bikes. not that i've seen, anyway. and it would be funny if someone did, because they'd end up with a motored bike that's slower than they could pedal.

I'll go with you on the $10k thing but there is a wide gulf between a walmart $99 special and that 10 grand puppy. For just a couple hundred bucks at a bike store you can get a bike that is lightyears ahead of the dep store junk. Does everyone need it? Of course not, but it sure could make life easier. I was planning on motoring a Kona 29er that I've got but come to think about it I might have to put that puppy on an old Airborne Ti frame that's not doing anything! LOL

i've never had one just suddenly slip and get cut. it usually takes a few days or weeks of neglect before that happens. it's a 5 minute fix.

Same here.
Steve

 

[Blakenstein]

Those sockets that fit the crank cartridges are kind of hard to find-I was very fortunate to get one. Konas are great bikes-I had one once but it got stolen-I was in the hospital, and my bike was locked in underground visitor parking right in front of security camera-when I questioned security, they said that they had no tapes. Konas are very fast bikes.Mine was an old one with a chrome/mloy frame.

 

[bairdco]

"euro" was just the name given to the smaller, 3 piece crank bottom bracket by cyclists in the 70's, when everything had to be "campy," and french, like their heroes.

i also want to clear up that i'm NOT in favor of department store bikes. finding a good old american cruiser is so easy, and high quality parts are still cheap. i just bought enough well made parts, minus frames and forks, to build two bikes, for about 250 bucks. (one piece cranks and a bottom bracket are $12 for both.)

 

[bairdco]

here's a funky tire/tube slip "solution" told to me by a hardcore mountain bike buddy of mine.

after using black vinyl electrical tape for a rim strip, he'd take four 6" pieces of duct tape and put one over the valve stem hole, and the others at opposite sides of the rim.

then he'd heat them up with a hair dryer till they were melt-y, and peel them off, leaving the gummy residue behind. then mount his tires and tubes.

the sticky goo would be on the rim strip and the insides of the rim as well, and he says it cured his tire/tube slippage.

dunno if it works, or how long it'd last before turning into that old duct tape crust, but he goes thru tires and tubes like crazy anyway, because, like i said, he's hardcore.

 

[Techbiker]

The last time that I checked at the bike store, the cheapest bike was $350. This was just a basic mountain bike with front suspension, whereas Walmart bikes are $99 and for many people hold up just fine for what they do with them. For a quality bike today, you will need to spend $500+ and for many casual bikers, I don't see that happening.

I would just make sure as a rule of thumb that moving parts on any bike are in good condition.

 

[lilhog]

when mounting the tire on the rim, inflate it to it's max psi maybe even a little more and check around the wheel to make sure that the tire’s bead is seated on the rim. Once you’ve made sure of that, deflate it. As it deflates you’ll hear and maybe even see the tube shift into a more natural position inside the tire. This is because when we cram it in there and inflate it, it may not be in the best position for it, but it can’t get there because of the pressure. Once again make sure that the stem is centered in the valve stem hole as you inflate it to your riding pressure.

taking this quote further, After putting a little soft air in your tube BEFORE installing it in your tire and then finish putting the tire on the rim, THEN put in a little more air, THEN work the beads (the thick part that has wire or kevlar moulded into the tire) around the rim pushing with your thumb on one side and your fingers on the other. The trick is that your tire is made for this and has a small line of rubber that goes around the tire just above the bead. This line is more accurate on better tires. Work the tire with your thumb and fingers and very light pressure in the tube untill the line is equal distance from the rim all the way round and the stem is of course straight up and down. NOW do the above lovehamr quote.
I use kevlar beaded tires because everything about them is the best and you never get a lumpy ride unless you skid like a dumby. I also use mr tuffys and heavy duty tubes and slime. We have these rock hard little "tumbleweed" thorns here that Im seeing around the country more and more. One will kill your ride. Now my tire can be covered with them and I just laugh like a mad scientist.
PS file a steel rim all you want, aluminum is better for your tube

 

[RecycleBill]

I am using a GEBE Tanaka 40cc belt drive with a expansion chamber exhaust
and a high performance carburetor and I am having trouble with rear blow outs.
I was going 35mph for about 9 miles with throotle left to spare. The tires , tire liners,
and slime tubes and wheel set are of decent quality. The trouble is at the valve stem,
either the tire and tube is slipping causing this. Does anyone else have this problem
while going at higer speeds? How can a person fix this issue? I am using about 60psi
in both tires. The front tire seems to be doing ok at these speeds. Will I have to go to
clincher style rims?

There's more than one way to skin a cat. Here's some of the ways I've managed to solve tire blowout problems:

Switch to 100psi tires and tubes and inflate them to 100 psi. Animal makes a great 100 psi slick but there are other great tires as well.

If you happen to be running a 20" wheel you can fit a !6" x 2 1/4 DOT RATED moped tire on the rim along with a moped tube-- preferably a tube that has a threaded valve stem (Of the Schrader style) that allows you to lock it down with a nut. Such tubes were common place on older motorcycles but can be hard to find these days. And they cost more to make.

If you're running a 26" wheel and have a wide enough frame you can go to your local Whizzer dealer and buy a 26" x 3" Kenda DOT RATED tire like Whizzer is putting on the new Ambassador. Cost: $55-$60 new.

A 3rd way to skin that flat cat is to go to your local hardware store and buy a rubber grommet just big enough to slide over your valve stem and drill the hole in your rim just big enough to fit the grommet. A grommet will cost less than $1.oo.


Of course, none of these or anyone else's suggestions are worth a flip if your tires and tubes aren't correctly installed and inflated.

 

[ez-bike]

I agree with those that say buy the best. Don't cheap out on saftey

 

[lowracer]

Get rid of the tubes, liners, & slime & try Stan's No Tubes. I have used this product back in my MTB racing days with never a flat & decreased rolling resistance...