question for you large brained bikers!

[IGGY]

Hi all-new biker, new bike. I've changed two flats, before I even had ten miles on my bike! However, now have more miles but this has been a problem from day one:
When I ride, I feel this: du-dum, du-dum. I slow down the "bu-bump" slows down, I speed up, I don't feel it as much.

Is this what is referred to as "wheel trueing?" Does this happen to everyone, (at first I thought I was fixing my flats wrong, but they've been okay.
Tonight, as my ride went on, it seemed to get worse.

anyone????

[DebW]

I actually had someone in the bike shop yesterday with that problem. The bike was 1 week old, but he had changed a flat on it and the tire didn't seat properly. There was one low spot in the tire that thumped like that. Spin your wheel and look at the rim between the brake pads. If the rim isn't wobbling between the pads, look at the tire. Spin the wheel and look at a tangent point on the outer edge of the tire. If the tire dips in one spot then that might be the problem. Let air out of the tire down to about 20 psi and see if you can get that part to lift up even with the rest of the tire (compare next to the rim). Pump it up, stopping frequently to push that spot away from the rim until it rises. if it doesn't want to rise, try some liquid soap on the part of the tire that wants to stay inside the rim.

[singletrackmind]

You true a wheel using the spokes to create even tension on the rim, creating a round wheel.
Spin the wheel around while you're not on it. You will prolly see your du-dum. You may even find a loose spoke. With 10 miles you'd expect your wheel to be true unless you've managed to whump it on something....you might have your bike shop true it again, or at least check true. A bad tire could also cause a ka-thump.
As for the flats, keep track of where they're happening, in towards the wheel or out towards the tread or sidewall. If in towards the wheel, do you have quality rim tape? Is there a spur that's putting a hole in your tube. If it's out towards the tread are your wheels aired up enough (two punctures a rim's width apart indicates a low tire). Otherwise, perhaps a tire liner might be in your future?

[makbike]

Check the tire above the valve stem. I wonder if this is the issue. If this is not seated properly it will cause a hump in the tire. Allow the tire to slowly rotate and watch to see if you notice a bump. If so, let some air out, push the valve stem up into the tire and them pull it back down. Inflate the tire and give it the spin test. Good luck!

[Geonz]

It's usually not the wheel that's out of whack but the tire as DebW said. My bike shop has a spritzer with soap in it that theyuse for just such situations ( especially since they have a lot of cruiser and 3-speed kinds of customers, and those tires seem to sit wrong mroe often). It's like riding on an egg instead of a wheel!

( figured this would be a question abotu large sized helmets)

[smilingcat]

One thing not mentioned was... is the tube twisted inside the tire by any chance. This too can cause the tire to inflate "funny" and develop a flat spot.

best way to get the tube inside the tire is coat the tube with talcum/baby powder. real light coating by pouring bit of powder in your palm and run the tube over the palm of your hand.

Make sure the tube is not twisted when it goes in the tire.

And make sure your tire is seated properly.

smilingcat