Just out there yesterday giving my nice new fat Monty tire a test ride when, wobble, weave, hisssssssssss, yup a flat.
I had the tire at 30 pounds pressure and I weigh about 125 so I don’t think the tire pressure was too low for a pinch flat but that is sort of what it seemed like. The tire didn’t have anything penetrating it and the tube had a small (1 mm), incision like slice on the side that lays againt the rim. Rim strip seemed to be in the right place covering the spoke holes.
What do you think? Maybe it was just a defective tube?
I had been riding for about 45 minutes before the flat. I was doing some simple trials, nothing major, just to get a feel for the new wheelset. Which, other than the flat, is fantastic. So sweet to land on that nice wide tire.
Well, I have just replaced the tube with another (20 X 1.75/2.125) - which I estimate will be the correct size for the Monty.
It is nice and sunny out this morning so I am off to test ride the new Monty wheel a second time. Wish me ‘no flat’ luck.
Did you feel the rim for sharp spots? I did a search for a simmilar thread (I got my new Monty and it popped the first time I sat on it) that was posted a while back, but found nothing; as I recall, they fond spur on the rim… (or was that a Coker rim?)… arg…
I had my first puncture in the muni tyre last weekend. Fate must have been smiling on me then, as it happened within sight of my front door after a ride of about 12 miles!
Mine was much more obvious… half a tree wedged through the tyre, straight into the tube.
It was weird riding on it as it went down… I didn’t notice the puncture but it seemed to be slewing across the path in a strange way. Then on attempting to turn the corner, it went straight on, and I fell off…
I’ve been running a 24" x 1.75" tube in my Gazz since I got it ! I’ve been pretty lucky because it still hasn’t got a flat. I’ve got two thick 3" tubes sitting at home waiting.
The Monty rims do have a tendency to pop tubes. I suggest putting rim tape instead of a rim strip on before you put the new tube on. This is the only way to avoid another such incident.
In article <Erin.jis8m@timelimit.unicyclist.com>,
Erin <Erin.jis8m@timelimit.unicyclist.com> wrote:
)
)Just out there yesterday giving my nice new fat Monty tire a test ride
)when, wobble, weave, hisssssssssss, yup a flat.
)
)I had the tire at 30 pounds pressure and I weigh about 125 so I don’t
)think the tire pressure was too low for a pinch flat but that is sort of
)what it seemed like. The tire didn’t have anything penetrating it and
)the tube had a small (1 mm), incision like slice on the side that lays
)againt the rim. Rim strip seemed to be in the right place covering the
)spoke holes.
)
)What do you think? Maybe it was just a defective tube?
If it was a fast flat, it’s possible that the tube was pinched between
the tire and rim when it was installed.
-Tom
Thanks for all your feedback. I didn’t actually have time this morning to get everything back together… work, it can really interfere with things sometimes.
Anyways, I jumped on my 24 inch commuter and headed to school. On the way home I stopped to pick up a BMX style heavier weight 20X2.125 tube. I’m going to pull everything apart again and check the rim and tire again. And then install the more heavy duty tube.
Sal, how is the rim tape different from the rim strip, wider perhaps? Hummm, I’ll have to consider that when redoing my repair job.
Also, just wondering what most of you run your Trials tire at in terms of pressure? I was thinking about 25 psi would be nice but it was at 30 when I got the flat.
Still not sure what caused the 1 mm slice along the tube. It didn’t have the two points side by side that you described Sofa.
And as for getting the tire off the rim, Jagur, its no problem. In fact the Monty is a kinda loose fit on the rim and I have to fiddle with it a bit to get it centred on the wheel so it doesn’t rub the frame on one side.
Rim tape is thicker. Rim tape is also sticky so it stays in place on the rim and won’t move around on the rim potentially exposing spoke holes. You can get rim tape at any bike store. Velox is a popular brand, but there are others.
I got one flat on a new uni when there was a sharp metal sliver still inside the rim. The metal slivers come from when the spoke holes are cut. Usually the sharp metal bits are blown out of the rim with compressed air when the wheel is built, but this one managed to stay stuck just waiting for the right time to break free and pop my tube. Check the inside of your rim (around the spoke holes etc) for sharp metal slivers.
Other possible causes for your flat could be part of the tube getting pinched between the tire and the rim. Or the tube could have had a twist in it when it was installed.
One thing I like to do is put a bit of talc powder (baby powder with talc) on the tube and on the inside of the tire. This allows the tube to slip around in the tire and can help keep the tube from folding over or getting pinched. Sometimes a tube that is installed without talc can stick to the inside of the tire. Having the tube stuck to the inside of the tire may make it more likely for the tube to get pinched between the rim and the tire when the tire folds over. Some bike folks say the talc treatment doesn’t reduce the risk of getting a flat, but I do it anyways.
Whooooofff, I am finally finished… was that a job!
The heavy duty inner tube just kept wanting to suck it’s valve stem back into the rim. I pumped and pumped and pumped, then took off the pump attachment, zummmmm, in slides the valve. The first time it happened I had to poke in to the hole in the rim, with a chopstick, of all things! I was able to reach the valve stem that way and let the air out and reinsert the valve all over again.
pump, pump, pump… till I was up to about 30 lbs, finally the sneaky valve stem stayed put… sort of. I still have my eye on it now! I think I need one of those nuts that screws onto the valve and against the rim to avoid further slippage. Off my my LBS tomorrow I guess as I searched high and low around the house for a spare one of those ‘retainer’ nut but to now avail.
Well that was an unexpected challenge.
And then there was trying to get everything centred on the frame. The Suzue hub is an 1/8th of an inch narrower than the original freestyle hub so the frame needed a bit of a squeeze to meet up with the bearings. It didn’t help matters that on one of these ‘squeeze’ maneuvers I got my finger caught between a spoke and the frame, yowwwwwwww
So it took a bit of fiddling to get things lined up and the bearing caps to the right tension. Whofff, it was all such a deal, I think I’ll wait 'till tomorrow before I attempt a real test ride.
Good thing there is a three inch trials frame from Darren on the way down the road… that should take care of the centering problems
