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  1. #1
    renaissance cyclist
    Reputation: debusama's Avatar
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    sooo many pinch flats

    I have a really fun trail that runs near my house which is where I do most of my off- road training. It isnít a particularly technical trail by MTB standards, but itís a little rockier that one would typically take a cross bike on. My Cross bike came with very narrow wheels that were constantly going out of true and required rebalancing, so I order a pair of wheels from bicycle wheel warehouse (my cross bike is a single speed so options were limited) with Mavic A319 rims that are much wider.

    With the old wheels I pinch flatted once, but I was running only about 35 PSI on a rocky trail. With the new wheels, even running more like 40-45 PSI I was pinch flatting every time I took it out on the trail. I had read a lot about how the Clement PDX worked well at lower pressures and even at 60 PSI, I pinch flatted again. I really donít want to try and race with 60 + psi in my tires when the season comes, but I feel like I've really dumped enough money into these wheels/tires to be dealing with pinch flats or untrue rims every time I breathe on this damn bike. My next thought is to try latex tubes, but Iím skeptical about how much that will really help and I donít want to keep throwing good money after bad if, for instance, My rims are just too wide to be used with a cross tires.

    Any idea what I might be doing wrong here?
    Last edited by debusama; 07-06-2014 at 07:50 PM.

  2. #2
    mtbr member
    Reputation: Eric Malcolm's Avatar
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    I would buy a set of decent rims and have the wheels re-built. I know, more expense. It would appear to me that a narrower rim eg: DT Swiss RR415 or similar would be a better choice and yes, the latex tubes do improve the situation. Don't confuse CX and MTB SS wheels sets as being similar, the MTB's are wider though the same 622mm diameter. Many here will suggest going tubeless, and this is worth investigating.

    Eric
    If I don't make an attempt, how will I know if it will work?

  3. #3
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    well, you should be fine pressure wise. Perhaps this area isn't appropriate for your cx bike? Or maybe (and not trying to be an ass) you need to pick better lines?

    A teammate got a disc cx bike last year and used his Arch Ex wheels w/ SB8s as a screw around setup. He ran tubeless for a bit but had burping problems.

    A small suggestion though regarding future wheels. I no longer build/buy SS specific wheels as it limits the market for resale if i decide I no longer like them

  4. #4
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    How big are the tubes?

    I've found that using tubes that actually fit the tire without being stretched helps with pinch flats and punctures. If the tube isn't stretched, then it's a bit thicker, and not as prone to "popping" when compared to the tiny tubes that "match" the size of the tire.

    For example, I've got a 35-42mm tubes in 33mm tires on the CX bike, and they still aren't as big as I'd like. I've got a 3.0" tube in a Conti Race King 2.2 that fits perfectly. It's not stretched at all, and not bunched anywhere. Haven't had a flat on that bike in a long time.
    '02 Kona Bear - '01 Schwinn Homegrown Comp - '12 Giant Defy 1 - '14 Kona Jake the Snake

  5. #5
    Now older but less slow!
    Reputation: TheNormsk's Avatar
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    I had a similarly rocky trail near where I live. I might get a pitch flat on that trail 50% of the time (it is a trail that I enjoy my 5.5" FS rig on) but it is only a 1/4 mile long (if that) and everything else can be ridden on the cross bike so riding the FS for that one section seemed overkill..

    I also got a lot of punctures due to thorns. In the end (after my last wheelset failed on me) I upgraded my wheels to the Velocity A23 Pro build and I mounted Specialized Tracer Pro 2Bliss with Cafelatex sealant. I'm very happy with the combination of light weight, no inner tubes so no pinch flats and no punctures (so far).

    Perhaps it's time to upgrade to tubeless if you want to continue to ride that rocky trail and maintain sanity?

    EDIT: I just noticed that you are single speeding so a wheelset like the Velocity will not work for you but it still may be worth check out their A23 rims and rebuilding your wheels to go true tubeless.

  6. #6
    renaissance cyclist
    Reputation: debusama's Avatar
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    Cross racing is really my # 3 discipline. My bike is a phantom cross Uno from bikes direct that I only paid $399 for about three years ago just to try cross racing. I have generally been getting my A$$ handed to me in the single speed pack which is mostly filled with CAT1/2 types, then taking my Single speed over to the Cat4 race to finish in the middle of the pack. I had kind of accepted that I just suck at cross racing and I might just never see a podium like I sometimes do in Road and Mountain bike races. Nonetheless, I've done about 20 cross races in the last few years and I think I accomplished my original goal of ďtrying outĒ cross racing. Might just be time to stop wasting money on trying to lipstick that pig and go get a real cross racing bike.

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