Vibration at 70+ mph

dregier · 07-16-2013, 09:18 PM

I took my Nomad to Memphis and about half way there I noticed a vibration in the bars. When I let go of one of them it shakes pretty good on my 16" apes. I grabbed a hold of it again quickly and slowed down a little until we could get to a spot to pull off the road. I checked as much as I could think to check and it all looks good but the vibration is still there.

Tire Pressure OK
Visual Tire check looks OK
Bars are tightly fastened
Engine mounts are tight

I run the dyna beads in my tires so I don't think it is a balance issue. Maybe a broken cord in a tire? Bearings? Any ideas?

I did ride the bike back home from Memphis 300+ miles and as long as I am under ~70 it doesn't vibrate.

recumbentbob · 07-16-2013, 11:04 PM

What year, how many miles on it, what mods if any.
Gibe us something to work with....

**ringadingh** · 07-16-2013, 11:06 PM

My bike tends to wobble when I let go of the bars, the problem gets worse as the tire wears, even though there is still decent tread on it. Most likely a new tire will make it dissappear for a while, also check the neck bearings.

racinfan101 · 07-16-2013, 11:21 PM

I tend to think along the same lines as ringadingh.

dregier · 07-17-2013, 09:49 AM

I kind of thought the same thing about the tire since the vibration is felt in the bars and not my feet or seat. I ordered a new tire and will get it put on this weekend. Think I might try Ride On this time instead of the dyna beads.

dank · 07-17-2013, 10:03 AM

Your tire may have developed a harmonic vibration, which can occur even with a newly balanced tire. Not sure what dynabeads do in that regard. If that is the case, usually you find it starts to be noticable, builds for 2-3 mph, has a peak, then lessens for 2-3 mph as you speed up, then is gone, and will happen every time you pass through that speed range. Can also be caused by a slightly bent/flattened rim. I expect your new tire will resolve the issue.

macmac · 07-17-2013, 11:10 AM

What YEAR?

What tire is it..... How are the brakes? 2 tests with the ft wheel off the ground spinning the wheel have some one set the ft brake and let go fast.... You are feeling for the slightest drag...

If this bike is older?????? If t sees a lot of sun all year long the rubber brake flex lines may be breaking down. There is a thread on this now with a bike from year 2000.

If the brake(s) are dragging it will heat a rotor and that rotor will create a vibration.

Test 2 pull the calipers and hang them spin the wheel feeling the bearings.

It could be the tire too.

16 inch bars exasperate the problem but won't cause the problem.

dregier · 07-17-2013, 11:38 AM

It is a 2006 Nomad with braided brake lines that are only 2 years old. I ordered a new tire and will put it on this weekend. I will double check the wheel bearings then. If the new tire doesn't help then I guess I will have an almost new one on the shelf to put back on later.

recumbentbob · 07-17-2013, 12:20 PM

How much pressure do u run?
I would run 40 or 42 psi

id-man · 07-17-2013, 12:31 PM

When I bought my Nomad a couple months ago it would shimmy at highway speeds when I let go of the bars. New tires solved that so I hope you fare as well. What I wanted to mention is that in my case both tires were not that noticibly bad by visual inspection. While the front showed worn tread, the back only showed slight cupping, hardly noticible till you really felt carefully, yet I believe it was just as contrubuting if not the main culprit. The worst is that both tires were old - like since 2004 so they were hard and dead, although showed no dry rot or cracking.

id-man · 07-17-2013, 12:42 PM

What I want to hear more about is this "harmonic vibration" that Dank mentioned. My bike does that at 90. It's not a shimmy it's a shake right in the handlebars no matter how hard I grip them. I've been afraid to push past about 89 not knowing how much worse it might get or for how long. Not that I go over 90 too often but I would love to get it diagnosed and fixed. Any ideas how to tell the precise cause?

dregier · 07-17-2013, 12:42 PM

I run 42 in the front tire which is a Dunlop D404 with about 3000 miles and a car tire on the back with about 20000 miles on it.

davidhollinger · 07-18-2013, 12:37 PM

I have the exact same front tire and the exact same vibration. I posted it on here and Mas Tequila came back and said that tire never stays balanced. I am gonna try to get to the shop and try Dyna beads this weekend but it is supposed to rain all weekend. Do you still have the old metal weights or run beads?

dregier · 07-18-2013, 03:53 PM

I run beads in my tires because of the change in tire balance over the life of a tire. I am thinking next time of going to the Ride-On Tire Sealant/Balance stuff but I can't buy it in my area. Not sure I want to wait for someone to ship it to me. Might have to run beads again.

07-16-2013, 09:18 PM	#1
dregier Member Join Date: Apr 2010 Location: Ozark, MO Posts: 63	Vibration at 70+ mph I took my Nomad to Memphis and about half way there I noticed a vibration in the bars. When I let go of one of them it shakes pretty good on my 16" apes. I grabbed a hold of it again quickly and slowed down a little until we could get to a spot to pull off the road. I checked as much as I could think to check and it all looks good but the vibration is still there. Tire Pressure OK Visual Tire check looks OK Bars are tightly fastened Engine mounts are tight I run the dyna beads in my tires so I don't think it is a balance issue. Maybe a broken cord in a tire? Bearings? Any ideas? I did ride the bike back home from Memphis 300+ miles and as long as I am under ~70 it doesn't vibrate. Login or Register to Remove Ads
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07-16-2013, 11:04 PM	#2
recumbentbob Sr. Member Join Date: Mar 2009 Location: Newburgh IN Posts: 3,404	What year, how many miles on it, what mods if any. Gibe us something to work with.... __________________ VBA #01084 "A well regulated militia being necessary to the security of a free State, the right of the People to keep and bear arms shall not be infringed."
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07-16-2013, 11:06 PM	#3
ringadingh Join Date: Aug 2007 Location: Newmarket Ontario Canada Posts: 35,387	My bike tends to wobble when I let go of the bars, the problem gets worse as the tire wears, even though there is still decent tread on it. Most likely a new tire will make it dissappear for a while, also check the neck bearings. __________________ 2002 Nomad aka Bountyhunter VBA #27 VROC #18951
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07-16-2013, 11:21 PM	#4
racinfan101 Member Join Date: Jul 2011 Location: Lewistown IL Posts: 301	I tend to think along the same lines as ringadingh. __________________ Randy aka racinfan101 VBA #01806 Central IL Vulcan Riders
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07-17-2013, 09:49 AM	#5
dregier Member Join Date: Apr 2010 Location: Ozark, MO Posts: 63	I kind of thought the same thing about the tire since the vibration is felt in the bars and not my feet or seat. I ordered a new tire and will get it put on this weekend. Think I might try Ride On this time instead of the dyna beads. Login or Register to Remove Ads
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07-17-2013, 10:03 AM	#6
dank Sr. Member Join Date: Sep 2007 Location: Michigan Posts: 1,595	Your tire may have developed a harmonic vibration, which can occur even with a newly balanced tire. Not sure what dynabeads do in that regard. If that is the case, usually you find it starts to be noticable, builds for 2-3 mph, has a peak, then lessens for 2-3 mph as you speed up, then is gone, and will happen every time you pass through that speed range. Can also be caused by a slightly bent/flattened rim. I expect your new tire will resolve the issue. __________________ Dan K Member #100 2009 ST1300: Performance exceeding even Victory riders' boasts.
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07-17-2013, 11:10 AM	#7
macmac Sr. Contributor Join Date: Apr 2008 Location: Tamworth New Hampster 06 1600 Posts: 12,484	What YEAR? What tire is it..... How are the brakes? 2 tests with the ft wheel off the ground spinning the wheel have some one set the ft brake and let go fast.... You are feeling for the slightest drag... If this bike is older?????? If t sees a lot of sun all year long the rubber brake flex lines may be breaking down. There is a thread on this now with a bike from year 2000. If the brake(s) are dragging it will heat a rotor and that rotor will create a vibration. Test 2 pull the calipers and hang them spin the wheel feeling the bearings. It could be the tire too. 16 inch bars exasperate the problem but won't cause the problem. __________________ 06 1600 Nomad Just call me Mac molon labe come and get it
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07-17-2013, 11:38 AM	#8
dregier Member Join Date: Apr 2010 Location: Ozark, MO Posts: 63	It is a 2006 Nomad with braided brake lines that are only 2 years old. I ordered a new tire and will put it on this weekend. I will double check the wheel bearings then. If the new tire doesn't help then I guess I will have an almost new one on the shelf to put back on later.
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07-17-2013, 12:20 PM	#9
recumbentbob Sr. Member Join Date: Mar 2009 Location: Newburgh IN Posts: 3,404	How much pressure do u run? I would run 40 or 42 psi __________________ VBA #01084 "A well regulated militia being necessary to the security of a free State, the right of the People to keep and bear arms shall not be infringed."
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07-17-2013, 12:31 PM	#10
id-man Advanced Member Join Date: May 2013 Location: Cape Cod Massachusetts Posts: 822	When I bought my Nomad a couple months ago it would shimmy at highway speeds when I let go of the bars. New tires solved that so I hope you fare as well. What I wanted to mention is that in my case both tires were not that noticibly bad by visual inspection. While the front showed worn tread, the back only showed slight cupping, hardly noticible till you really felt carefully, yet I believe it was just as contrubuting if not the main culprit. The worst is that both tires were old - like since 2004 so they were hard and dead, although showed no dry rot or cracking. __________________ 2004 Nomad 1500FI - weeeeeeeeee! Last edited by id-man; 07-18-2013 at 12:51 PM.
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07-17-2013, 12:42 PM	#11
id-man Advanced Member Join Date: May 2013 Location: Cape Cod Massachusetts Posts: 822	What I want to hear more about is this "harmonic vibration" that Dank mentioned. My bike does that at 90. It's not a shimmy it's a shake right in the handlebars no matter how hard I grip them. I've been afraid to push past about 89 not knowing how much worse it might get or for how long. Not that I go over 90 too often but I would love to get it diagnosed and fixed. Any ideas how to tell the precise cause? __________________ 2004 Nomad 1500FI - weeeeeeeeee!
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07-18-2013, 12:37 PM	#13
davidhollinger Sr. Member Join Date: Aug 2012 Location: Central Alabama Posts: 2,188	I have the exact same front tire and the exact same vibration. I posted it on here and Mas Tequila came back and said that tire never stays balanced. I am gonna try to get to the shop and try Dyna beads this weekend but it is supposed to rain all weekend. Do you still have the old metal weights or run beads? __________________ I would be patient, but it takes too long!! David Hollinger 2002 Beige 1500 "Hannah2" VBA # 02195
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07-18-2013, 03:53 PM	#14
dregier Member Join Date: Apr 2010 Location: Ozark, MO Posts: 63	I run beads in my tires because of the change in tire balance over the life of a tire. I am thinking next time of going to the Ride-On Tire Sealant/Balance stuff but I can't buy it in my area. Not sure I want to wait for someone to ship it to me. Might have to run beads again.
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