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  1. #1
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    flats & tire pressure from a newb

    Hi all,
    Just discovered the site doing some reasearch & it looks fabulous. Can't wait to visit often. I've been having some problems with by bike & thought someone here could help me.

    I'm a 6'2" 370lber who bought a 2007 Daimondback Maravista Hybrid on closeout last year & rode it some, say ~100 miles with no real problems. I really wanted to get into biker more this year so I've been hitting it hard & put 225 or so on this spring. I started poping spokes on my rear wheel like they were pez so my LBS encouraged me to but a Sun Rhyno lite wheel which I did last week. Nice heavy duty rim with more spokes (I think 32? maybe 26?)

    They transfered over the tire from my old rim which is a 700 x 40c Kenda Cross w/ K-shield. I've never had a flat on it with my old rim but now, I can't go 10 miles without getting them. The LBS is doing their best to help me, the last time I brought it in they tood the rim & sanded it all down to make sure there wasn't any sharp sopts, wraped the rim & tape & then added the cloth back.

    I took it for a short 1 mile spin yesterday & while it hasn't gone flat yet, I noticed that it really seems to bulge more than it did on the last rim. I've got it air up to 85 psi which is the max that the tire says to go. So here's my question(s)?

    Ps. I tend to ride strictly on paved trails or a bit of road to get to the trails. Nothing crazy.

    1. Should I over inflate a bit to see if that helps? whats the danger in doing so?

    2. Is there a different type of tube to look for? Maybe a different tire? My current one's supposed to be kevlar weaved to resist against punctures.

    3. Anyone looked into airfree tires? Seems a bit wierd but if they really work I might be interested.

    4. Is this not the best rim for me? I can probably bring it back still but would need something else since my old one couldn't stand up to my Phatness.

    Thanks for any & all advice you might have. I really miss riding but don't trust my bike to go 10 miles now.

  2. #2
    your nightmare gal chipcom's Avatar
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    What kind of flats have you been getting? Were you finding objects that caused the 'punctures', or were actually getting pinch flats, rather than punctures caused by a foreign object?

    I'm gonna assume they were pinch flats...pump up your rear tire to 90-95lbs, while leaving the front at 85. Check your tire pressure before every ride.
    "Let us hope our weapons are never needed --but do not forget what the common people knew when they demanded the Bill of Rights: An armed citizenry is the first defense, the best defense, and the final defense against tyranny. If guns are outlawed, only the government will have guns. Only the police, the secret police, the military, the hired servants of our rulers. Only the government -- and a few outlaws. I intend to be among the outlaws" - Edward Abbey

  3. #3
    just pedal donalson's Avatar
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    like he said... where they punctures or pinch flats?...

    many times it could be something stuck in the tire... next time the tire is off take a cotton ball and rub it along both the tire and the rim... if there is any burs or something catching it'll snag a small bit of the cotton ball...

    beyond that sorry don't have any info for ya
    mtbr clyd moderator

  4. #4
    Uber Goober StephenH's Avatar
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    First off, you need to fix your own flats if you ever plan to ride more than two miles from your house.

    As to having flats, you need to know where the hole was. If something went through the tire, then sanding the rim isn't going to matter.

    Airfree tires seem to not be very popular, and very very few cyclists use them. Pneumatic tires are the latest invention; air-free is what they had before.

    Make sure you're gauging pressure accurately. I've got a floor pump with gauge that isn't terribly accurate.

    Changing the tube won't affect how much the tire bulges out. It may affect the number of flats if something odd is going on, but under normal conditions, it wouldn't affect that, either.
    "be careful this rando stuff is addictive and dan's the 'pusher'."

  5. #5
    Senior Member Plynthblox's Avatar
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    Is the new rim narrower than the original?

  6. #6
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    I'm not sure what a pinch flat would look like, but I have yet to find anything in the tubre or tire. I do know how to change my tires & inspect them manually when I do a change do see if anything is in there. I don't know if the rim is narrower or not. I have been using the guage built in to my air pump so maybe I need to double check its accuracy. I will attempt to go up to 90 or even 95 just to see if that makes a difference. Thanks for you thoughts so far & feel free to add more if anyone has some.

  7. #7
    Senior Member Wogster's Avatar
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    Quote Originally Posted by mipo777 View Post
    I'm not sure what a pinch flat would look like, but I have yet to find anything in the tubre or tire. I do know how to change my tires & inspect them manually when I do a change do see if anything is in there. I don't know if the rim is narrower or not. I have been using the guage built in to my air pump so maybe I need to double check its accuracy. I will attempt to go up to 90 or even 95 just to see if that makes a difference. Thanks for you thoughts so far & feel free to add more if anyone has some.
    There are 3 kinds of flats:

    Outside Punctures, when something sharp goes through the tire and puts a hole in the tube.

    Inside Punctures, this is a kind of puncture, it's caused when the rim strip is in the wrong position and a spoke end cuts the tube. There are two causes for this, the first is that the rim strip is not properly installed, the second is that the rim strip is not made very well. Often bicycle manufacturers use a simple rubber strip, that is not much thicker then the tube itself, they sometimes squish out of the way when riding, allowing spokes access to the tube. A better quality is a cloth strip that has glue on one side that sticks to the rim. Another option are little rubber plugs called veloplugs that fit into the rim holes around the spoke ends.

    A pinch flat, also called a snake bite flat, because there are two small holes close together like a snake bit the tube.

  8. #8
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    Thanks, the one I changed was a single small hole so it wasn't a pinch flat. The LBS has since redone the rim strip with take so hopefully that doesn't end up the issue. Would changing tires to something like a gator help in this case? I'd like to have a psi higher than 85 but not sure that with a hybrid I can.

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