I bought two new tires today, Geax Saguaro 29x2.2 for the front, and a Geax AKA 29x2.2 in the rear running tubes. They are wrapped around two new Mavic TN719 rims.
The rims have about 40 miles on them, and they had some no name Kendas (29x2.1) on them before I put these Geax's on today.
I checked both tubes and they both have punctures on the inner side of the tube, where they rest inside the rim. I've ran my finger along the rim and nothing feels sharp or jagged and I don't see anything at all that seems sharp or jagged.
I'm completely puzzled. I've patched both tubes but I don't want to put them back on until I've done a little more research and got a little input.
Anyone have any thoughts on this??
EDIT:
Just checled both tubes and they are sized 29x2.10...although I can't see how that would cause these punctures.
Mount the tire with the valve stem at a label so you know it's relation to the tube and the rim. Run it again. If/when it flats again you'll be able to know exactly where to look on the rim (or tire) for an issue. What rimstrip are you running? You could run a 26" tube in there and it's not gonna be an issue so the 2.1 is not the problem. With the information you have provided that's really all about you're gonna get. I agree with you though...generally in a pinch flat you're gonna see two nice holes that are very symmetrical. Odd that it would be a pinch and be one hole each time.
Sometimes the tube can get pinched between the rim and the tire's bead. Easy to do if the tire is tight-fitting on the rim. The tube will hold air for a while, then give w/o warning.
If it's definitely the rim side, not snakebite, no sharp irregularity on the rim, and your rim tape has completely covered the spoke holes, you've got a mystery.
As far as running Geax tubeless, I have had good success with the TNT's on converted and ZTR rims. If they are not TNT or UST tires, I'd be cautious running them tubeless.
I've never had good luck with tubes, particularly in the rear. I've been running tubeless for years with no problems getting flats. If you use UST certified tires and rims that will assure you have a compatible system. One set of wheels that I have are labeled "tubeless ready" so I run a couple ounces of Stan's sealant to ensure I get an air tight seal on those rims. I also run some Stan's in the UST wheels for a little extra insurance. The bad thing about going tubeless is the tires cost more.
I've had a problem with a Kenda Nevagal UST, seems they are not compatible with sealant. My Kenda had a blow out when the sidewall failed, seems the sealant attacks the rubber on the Nevagal.
Recently I tried running some Continental X-king 29er tires in a tubeless setup. That doesn't work either as the 29" X-kings are not labeled as tubeless compatible and there are pin holes in the sidewall that would not seal with Stan's. Seems this is a common issue with 29" X-kings, I went through 2 new X-kings, all with holes in the sidewall. I'll be swtiching back to a UST or tubeless certified 29" tire.
Not to derail the OP, but I have mounted up multiple xkings without issue. The sidewalls DO leak, but have always sealed up for me pretty quick especially after a short ride around the house.
I was just going to suggest closely inspecting the rim tape for creases or not quite covering all of the spoke holes. I recently rode a brand new bike that gave me three flats in three rides with the (tiny) holes on the underside of the tube. Replaced the rim tape, that had a crease in it, and no more flats until the tubes were discarded for a tubeless setup.
This is my first mountain bike, and the first time I've switched rims so I didn't even think of that. I wonder why the wheels came without the rim tape.
This gives me a good reason to go tubeless though, haha.
I was disappointed I only got out 5 miles, these Geax's felt awesome and very grippy.
New wheels usually come without rim tape installed unless they say they have it. Some new wheels will include a bag with rim tape/strips in it for you to install. New bikes should always have rim tape in the wheels because it is assumed that the bike is ready to ride.
I went to my LBS after work today and picked up some cloth rim tape, they recommended it over the typical plastic rim tape.
Put it on, remounted the tires and went and hit a few of the jumps to local kids setup in the retention pond, making sure to land on the back tire and no punctures. I won't have the chance to hit the trails again until Saturday, so that'll be the real test.
Holding off on tubeless for now, bought a new helmet instead.
Rim tape fixed it. Thanks for all the helpful replies.
Sent from my XT912 using Tapatalk 2
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Related Threads
?
?
?
?
?
Mountain Bike Reviews Forum
15.4M posts
515.2K members
Since 1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!