Balanced wheels?

[kdweb]

Got a weird little problem that has me miffed. I have noticed a minor jiggle that amounts to a feeling like my front tire is out of balance.
At high speeds ( 15mph plus) and on smooth surfaces ( asphalt) my front wheel vibrates like a have a rock stuck in the spokes! Prior to getting a new set of tires, I was attributing this to having a tube that I had put some slime into that I figured settled in the tube. Well new tires new tubes, and it is still there. Much less pronounced but still there....so I'm still in the wtf mode....thinking....thinking then bing! The computer magnet! That little .5 oz thing is doing it so off comes the magnet...nope! I still got the wobble.
Any ideas?

[august]

check all the spokes? maybe a nipple is stuck in the rim? quick release locked on tight?

[Dirt]

Check your hub bearings to make sure they're tight. Look at the bead of the tire and make sure it is evenly seated all the way around on both sides. Check the wheels for true and round.

Finally, wrap about 15 layers of duct tape around one spot in the wheel. That way it will be so far out of balance that you won't notice the little wobble anymore. You'll have bigger problems. ;)

Hope the serious suggestions help.

Pete

[Brizn]

Welp, it can only be a finite number of issues. :D

Can you produce the jiggle? This is the systematic part: see if you can produce the symptom yourself.. also see if you can remove the symptom in any way. Ie: try riding over 15mph-- does it still happen then? Try riding at 5mph- does it happen then? While applying brakes, while applying brakes at high speed, at low speed. While standing, while seated, while seated and braking, while standing and mashing, does it happen ONLY when you crank fwd on a pedal stroke?, etc etc etc.. this is how you start your diagnosis of such an issue... at least, that's how i do it anyway.

Does it happen when you're applying front brakes? (If yes, may be wheel out of true, dent in rim, weld joint in rim, etc).

Does it happen only while NOT braking? (If yes, could still be a dent in your rim or an 'out' rim).

Could also be (and this would be my first guess) that your axle needs to be tightened a little in your hub-- for this you'd need at least a cone wrench (bike specific tool) and another normal crescent wrench.

Could also be a loose headset thats sending a vibration.

[kdweb]

I can rule out the head set, that's cool.

The greater then 15 MPH is there for sure.. since it is ONLY when my hands are off the bars, I'm not gonna try it standing up....That would lead to other problems :eek:

It's not the hub...that's not got play in it.

I will check for true and the well seated tires....

Get back to ya...

[Brizn]

Ok, cool... so you've ruled out the headset and hub, which pretty much isolates the issue to the wheel (rim) itself. Good job! Post back.

[eloach]

My guess would be the wheel is out of round. Possibly just spoke tension problems, but could also mean the rim is trashed.

I've seen a similar effect when applying out of toe (improperly set up) rim breaks to a road wheel, but if it's happening during free roll with no breaking or pedaling I would guess the wheel.

This all presumes the frame is not bent or cracked anywhere.

[Nick]

I get it as well. Only when I sit up and cruise no hands. I'm running Tioga DH's - they're really heavy. It's probably something to do with the gyroscopic harmonic boogie. Nothing else is wrong with the bike.

The solution? Don't ride no hands when going fast enough to make the front end wobble. :)

[saxman]

I'd say spoke tension problems. I've had similar issues with brake rubs that only occur at higher speeds (both disc and rim). Once I tightened up the wheel a bit the problem disappeared.

[Dirt]

There is a point at which a rim gets so old and bent that you can no longer keep it true with correct spoke tension. If the rim has been structurally compromised, it might be possible to get it pretty close to true and round, but the weird tension needed to get it there would cause some "interesting" ride properties.

Looking at the true and round of the wheel in addition to the spoke tension might help find your problem.

Good luck.

Pete

[kdweb]

OK, from what I am reading and other experiences I've had, I want to check the out of round issue. I am running a new set of Bontrager Jones axc tr's and the wobble is less with these.

Here's gonna be the fun part...I don't own a trueing stand so anyone got any ideas for good make shift rigs to check that out? I recall something with a couple of tie wraps but the thing is a little foggy in the memory banks.

I'll get the rubber off the rim this weekend since it doesn't look like too much riding is happening this weekend! :rolleyes:

[Brizn]

I don't own a trueing stand so anyone got any ideas for good make shift rigs to check that out? Absolutely; leave the wheel on the bike, spin the wheel, and eye the brake pads to assess lateral true. For round, maybe take the tire off, remount on the bike, and put something level (horizontally) across the caliper..?? Keep chuggin!

[kdweb]

OK, I got a good idea after looking at my trainer this morning. I will rig up something and figure it out. I was getting hung up on the "point of reference" but after thinking about it and looking at a commercial stand, the point of reference is the wheel itself...duh!

[Cowboy]

Couldn't you just flip the bike upside down (use a block or book to set each side of the handle bars on if the blakes or shifters would hit the floor) and spin the wheel to see if it's out of true? Put a zip tie around the fork or chainstay pointed at the rim, and cut it off so it just touches the rim? That ought to give a good referance...

I'll be back in a few, gonna go try it, I'll take some pictues and report back.

ya'll come back now ya here...

[Cowboy]

Here's what I came up with:

Flip bike onto handlebars and seat. Put a tie wrap around one side of the fork, point it at the rim, spin the wheel. Depending on how the tie wrap is positioned/cut off you could watch the tie wrap flex as the rim is spun, or watch a gap grow and shrink...take a look at the pictures and see if this will work for you to get an idea of the trueness of your rim...GOOD LUCK!!!

http://i49.photobucket.com/albums/f267/MJC_Cowboy/MTB/maint/gage1.jpg
http://i49.photobucket.com/albums/f267/MJC_Cowboy/MTB/maint/gage2.jpg
http://i49.photobucket.com/albums/f267/MJC_Cowboy/MTB/maint/gage3.jpg

[BikerMiker]

It's most likely that the geometry of the bike has A LOT to do with the wiggly front end.

What frame and what fork with how much travel you got going on. I'm thinking you are running a hardtail with a longer fork, slackening the HT angle, creating the problem.

Try riding with no hands BUT sit as far forward on the seat as you can without having an intimate moment AND lean your chest down towards your handlebars.

If this fixes it, somebody owes me a damn Coke! Let us know.

mike

[kdweb]

Bingo Cowboy! That was the tie wrap thing I was trying to recall exactly! Good pull!

OK, I will rig that up in a bit.

Mike, you're on target with the hardtail but not what I would call an long travel fork. The wheels are Bontrager Mavericks on a Trek 6700 with a Sram Pilot SL fork..4" air and oil dampened if I recall.... In short, it's the stock setup including the tires. I don't do any big drops or stunt work routinely so unless I am just exhibiting normal wear and tear, chances are that I am a tad out of true and at those higher speeds on pavement, I am feeling it.

I let ya know.

Thanks for the memory jog Cowboy and BTW...are you still enjoying the weather? :rolleyes:

[Brizn]

maybe just the feeling of knobbies on pavement as opposed to soft dirt.

[kdweb]

OK, I think I have a fix……no more rolling down streets playing look ma, no hands! :(

The redneck truing stand worked great and I am very much in line and true with the wheel. As for the tire; there is wobble. None on the bead by the rim, very little on the side wall but as you go to the tread, there is about a 32nd of an inch at most.

I am going to take off the tire and play with it some more but not today…got family stuff to do.

[Cowboy]

OK, I think I have a fix……no more rolling down streets playing look ma, no hands! :(

The redneck truing stand worked great and I am very much in line and true with the wheel. As for the tire; there is wobble. None on the bead by the rim, very little on the side wall but as you go to the tread, there is about a 32nd of an inch at most.

I am going to take off the tire and play with it some more but not today…got family stuff to do.

If the rim is true, and the tire isn't...even though it looks good at the bead, you might be right on track with taking the tire off and putting it back on.

Put some kind of mark on the tire where you see it out of round, maybe with a plumber's thread caulk stick...? So you'll have a referance mark to see if it's just the tire when you get it put back on.
http://www.alltiresupply.com/Merchant2/graphics/00000001/crayon_27.jpg

Also, you might want to save yourself a chance of pinching the tube through the tire removal process, and just let all the air out, 'gently' spin the tire on the rim some, so you don't take a chance of damaging the valve stem on the tube. Then reseat the tire bead in the rim while airing it up, and see if that get's it back better into 'round'...?


-Cowboy



...And no I'm not enjoying the MD weather, I got home just in time for the rain/sleet/wind and cold... http://www.thesmilies.com/smilies/sad/bawling.gif

[Nick]

Mike's right on this one...
See if weighting forward alleviates teh wiggles. I'll bet it does. it does for me.