What's wrong with my new bike?

[mtneergrrl]

I am experiencing a pulsating sensation when I coast downhill on smooth surface roads. It feels like i am very gently and very quickly applying brakes repeatedly. I have had the brakes checked to make sure they are not contacting the rims. The problem does not happen when braking or when pedaling. Any ideas?

[DaveM]

Could be a bad bearing in one of the hubs. But my first guess is that one of the wheels is not well balanced due to a tire not seated well or a heavy reflector. Try lifting each wheel up and spinning it to see if you can feel which one is pulsing. Watch for wobble in the tire or try removing reflectors to see if that changes anything (though I would keep them on for safety).

I suspect that you only feel it when coasting because the braking/pedaling force overwhelms the pulse. But this is a guess.

[buzz]

Also, when the wheels are lifted, try moving each one side to side to see if there is movement. If so, the hubs need to be adjusted. Check also for any lose spokes as I have felt wobbles in the past and that is what it was.

[Billy]

(07-02-2010, 02:37 PM)mtneergrrl Wrote:  I am experiencing a pulsating sensation when I coast downhill on smooth surface roads. It feels like i am very gently and very quickly applying brakes repeatedly. I have had the brakes checked to make sure they are not contacting the rims. The problem does not happen when braking or when pedaling. Any ideas?

Hi, mtneergrrl. It could be a wheel that is slightly out of true. Flip the bike over so that it rests on the saddle and handlebars. Spin the front wheel and watch it from both the front and side. Then do the same thing for the rear. Look for wobbles or bulges or general oddness.
Also watch to see if the brake pads ever brush the tire itself.

Oh, it could also be a monkey tugging on the brake cable while you're not looking. It's not very likely, but you should never trust a monkey.

[trevgbb]

(07-02-2010, 02:37 PM)mtneergrrl Wrote:  I am experiencing a pulsating sensation when I coast downhill on smooth surface roads. It feels like i am very gently and very quickly applying brakes repeatedly. I have had the brakes checked to make sure they are not contacting the rims. The problem does not happen when braking or when pedaling. Any ideas?

Whow! what make is it? I want one.
Seriously, get it back to your supplier for a full service under warranty, or if bought on line, complain, complain, complain, then get it serviced at your lbs and send them the bill.
If that doesn't fix it and you can't live with it, ask for your money back.

[Bill]

What kind of bike is it Make(example Schwinn)/Model(example XR-75)/Size (example 26inch)? How many speeds (example 21)? Can you upload a picture?

[mtneergrrl]

thanks all for the great information. It has been most helpful. It at least gives me a direction to start. Ill keep an eye out for that monkey too.
thanks again.

[Bill]

Something else I was wandering, do you feel a bump like your going over a bump in the road that is not there? If so your tire may not be seated correctly.