High Speed Rear Blowouts

"The meek shall inherit the earth" I dont think that includes humans the way were going. Ants and turtles have been around for hundreds of millions of years, I think they know some thing we dont......all this started with a simple thought of the hare and the slow turtle, dont ask.
 
"There's always a bigger fish" seems to apply.

Qui-Gon Jin's most memorable quote from "Star Wars Episode One: The Phantom Menace."
 
so, uh, back on target here, there's some stuff called "rim cement" that's designed for tubular bike tires which might work. you could try it on the beads of your tires, maybe that'll help.

i wouldn't drill the rim out and put in a grommet. i think the air pressure, rider's stress, etc. might just blow it out. and it'd probably weaken your rim.
 
bairdco said:
so, uh, back on target here, there's some stuff called "rim cement" that's designed for tubular bike tires which might work. you could try it on the beads of your tires, maybe that'll help.
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That's a good idea—though I'd only use a small amount, I'm sure it's a pain to get off.

Also—you might try replacing your rim tape.

Usually tires shift because they're under-inflated.

You may have also damaged the valve stem area while inflating your tire (when pulling the pump off). I've ripped entire (previously undamaged) valve stems off of tires (both new and old tubes). And I have spaghetti arms. It's a fragile area of the tube.
 
Inflate to 65lbs or even 70!! Use the PRESTA type tubes that have a thread locking valve system. You will need an adapter for inflating.Make sure the valve is staight up and down while inflating.
 
I use Serfas Drifter S tires. I think they are the best motored bike tire made. Inverse tread, 4 layers of flat protection. I ride at 40 mph for 10 miles just to get to town. I think you need to get rid of the weight inside the tires. A Drifter S tire is 40 bucks they come in 1.75 and 2.0 width. Try one with just a hvy duty tube. No slime tubes. No flat protection strips. Make sure the hole for the stem has no sharp edges. Inflate to about 40 lbs and look at the stem. If it isn't straight drop the pressure to about 5 lbs and work it round till it is straight then ride at 60 psi. Since I switched to these tires I have had zero tire problems. With the inverse tread they are very smooth rolling and vibration free. The S stands for survivor series. I have about 400 miles on them now and they are showing almost no wear but they still have great cornering traction. These are far and away the best bike tires I have ever rode on.

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Junster - nice tires man!

I've been risisting the urge to get a nice set of streets for mine, what with winter just around the corner I figure no sooner than I ditch the knobbies - it'll snow...

I will admit I've been runnin' el'cheapos - just some random low cost tires I scored off a garbage bike. They must be fairly common because I've no less than three sets of exactly the same tread design - ALL off dead junkers! o_O (which is awesome given I really like the tread lol) No fancy liners, no sketchy goo tubes, just yer basic Walmart Bell tubes and inflated to 50psi.

I beat my ride mercilessly. Trails, highway use, even a mini "Death Race" tribute in an empty lot - I've never had a tire/tube shift on me or even a flat! Well, I did pop both the tubes the bike came with when it was new - but as they both "seam split" within 15 miles of each other I figure those were defective.

I wonder given what Junster and others have said - if perhaps alla fancy tire liners and whatnot are actually contributing to more problems than they're protecting against?
 
BarelyAWake said:
I wonder given what Junster and others have said - if perhaps alla fancy tire liners and whatnot are actually contributing to more problems than they're protecting against?
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I was wondering how effective the liners are myself. The have them at Walmart now for $9 so maybe give them a try and see for myself.

I do know the thorn-proof tubes and goo made a big difference for me. Used to get a flat almost every long trip but now only once every couple years. Thorn-proof helps a lot with punctures but also the goo stops un-noticed slow leaks which is the "silent killer".
 
My first set of tires were Kenda 26x2.5 tires with heavy duty slime
tubes. This is running the GEBE 35CC four-stroke set up and I have lots
miles with these tires with no trouble. The only problem is at speeds above
25 mph, they make an annoying road sound on blacktop payment.
I have serfa drifter tires 26x2.0 on my China-Girl 2-stroke engine set up
with regular size slime tubes. I have been putting alot of miles on this bike
recently with no tire problems.
On my GEBE 40CC 2-stroke I have Serfa Drifter 26X2.0 tires and regular slime
tubes that I did not have any problems with until recently I added the tire liners.
There is about 14 pounds of engine set-up weight over the rear tire. I had only
about 27 miles on the tire liner milage before I had the blow out.
The Serfa Drifter tires are a really good choice to me based on my experiance
with the store model stock tire. I have the Maxxis HookWorm 26x2.5 tires with
regular slime tubes on another project bike and have not got to try these out
yet. I was really surprised as to how thin these tires are. But I have no opion
on them yet until I get to put some miles on them. I run all my tires on the same
brand triple-v wheel sets..
I am learning alot about tires from this thread.....thankyou
 
I've just gotta get this off my chest. I've been a fairly serious cyclist since the early 80s. I guess I’m part of the "lycra crowd" when I'm doing a long road ride and sometimes when I'm MTBing as well, but I'm not so far gone that I shave my legs or anything like that. My best result in competition came in the TX state downhill championship, in 01 I think it was, where I won the "old guy" class (LOL). At any rate I keep reading on this forum about "slowing down" and "bikes weren't made for going that fast" and other such BS. I haven't even built a MB yet and I exceed 50mph on both my road and MTB about 6 times a week and whadaya know, I'm still here to talk about it. Now does that mean I want to dump it at that speed? Of course not. But I also use quality components on my bikes and good safety gear. It seems like many in the MB world build their bikes with spit and shoe strings and expect it to hold up. This goes hand in hand with the number of pics and videos that I've seen of MBers riding with no safety gear what so ever. Jeez, at the very least wear a good quality helmet. Any quality bicycle is more than capable of exceeding 30mph on flat ground with a strong rider, even my fat azz can do that for short periods. To expect less from a motor powered bike is just dumb. With that in mind, one's component and safety gear selection should become clear. The idea that exceeding a particular speed is going to lead to Armageddon can only be based on poor rider/builder choices and/or rider skill. These should be taken into account whenever someone is going to throw their proverbial leg over any 2 wheeled vehicle.

OK, I’m off of my soapbox now. So on to some possible solutions; #1 you’re running a lot of mass in your tires that probably isn’t needed with good shielded tires. #2 anytime you have a flat, analyze the tube to see where exactly the puncture is in relation to the rim and the tire so that the cause can be pinpointed. In your post you stated that it looked like the valve stem had been cut by the rim. This should only happen if the metal around the valve stem hole is rough and/or sharp and not covered by the rim strip, so look and feel to see if that is the case. If it is, use fine sand paper or a file to smooth it out or at least make sure that the rim strip is covering any sharp edges. While running 60psi in the tire, I wouldn’t expect it to slip or shift any significant amount so you might try this; 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. This is something I do every time I change a tube, hope it helps.

Steve
PS here is a great site to look at reviews of just about any MTB component, in this case tires.
Tire Reviews
 
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Good stuff lovehamr!

We'll try to forgive yer attire :p

One lil tip that's obvious but some may not know: Inflate a new tube just enough to give it shape then put it in the tire. This helps prevent folds and twists, particularly with a new tube out of the box. Having a lil pressure in the tube also allows you to reposition it to get the valve stem to line up better.
 
BA, good point and that goes with the use of presta type tubes because you can just use lung power to get them in enough shape to install properly.
 
I despise those presta valve stems and spent quite a bit effort drilling out holes in 700mm rims to accept normal tubes.
 
Why do you not like presta tubes ,besides the fact that you have matching valve holes in rims but only normal tubes.......I did what you did once, and 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 .:):)
 
Blakenstein said:
Why do you not like presta tubes ,besides the fact that you have matching valve holes in rims but only normal tubes.......I did what you did once, and 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 .:):)
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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.
 
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