Shake when slowing down

[loonytuna]

here's a new one!

When I slow down from around 45 to around 40, the front end shakes.

It's smooth at speed, no issues at all.

Ideas??

 

[elizilla]

Either a cupped front tire, or loose steering head bearings.

How many miles on the front tire? What kind of tire is it?

 

[tawilke46]

Had the same problem with my '98 Pacific Coast. Had the head bearings checked. They were within spec.
I think it was the cupping on my front tire. No head shake until I slowed down to less than 45 to 50 mph.
At the time I was thinking of installing a fork brace to see if that would fix the shaking problem (and maybe a new front tire), but sold the bike before I had a chance to do it.
I was running Metzler ME880 bias ply tires on the PC.

I am getting ready to install a set of Michelin Road Pilot 3's on my NT. Should improve handling quite a bit.

 

[WVRider]

The majority of the time this is caused by a cupped front tire as the others have mentioned. It has occurred on every bike I've ever had and is usually more pronounced when you have a load or passenger on it. I have never had one shake enough to cause a problem as long as you keep your hands on the bars. I've never changed tires due to that as most times you can get many more miles out of them. Always goes away when I put on a new set of tires as mine did just last month with the new set I put on. Have a little over 3000 miles on that set of tires and it hasn't come back yet but will.

PS; I put on the Michelin Pilot Road 2's front and rear and WOW what a difference. Way nicer tire than the OEM.

DJ

 

[Phil Tarman]

DJ, almost anything is better than the OEM! I've had Metzler ME-880s (radial front, bias-ply rear), BT-023s, and now Michelin PR3s. All of them have been better than the BT-020.

 

[loonytuna]

Bike has 2200 miles on it!

 

[loonytuna]

Either a cupped front tire, or loose steering head bearings.

How many miles on the front tire? What kind of tire is it?

2200 miles on OEM bridgestones

 

[Cnille]

What causes cupping?

 

[vzshadow]

I got almost 8000 miles on my original tires. They were pretty bad when I changed them and the shaking like you describe was pretty bad. New tires, PR2s, made all the difference.

 

[loonytuna]

It shouldn't happen with 2200 miles.

So here's the real question,,, since the bike was a 2010 bought in January 2012 and not knowing how long the bike was in the dealers inventory, would this contribute to the early cupping?

The tires could be 3 years old, which in itself does not bother me, there is no dry rot or cracking, but could it cause the premature cupping?

If so, shouldn't we warn buyers of leftovers?!

 

[loonytuna]

Forgot this....

Or are the OEM tires just garbage?!

 

[Papa Lou]

I've tried two sets of Avon Storms and they displayed the same cupping and bar shake as the OEM junk tires. The upside of the variable compound Avon tires was the 12K-15K I got out of them. I replaced the front ones only because of the cupping and shimmy. Went to PR2's and they have been great but are just starting to shimmy, no cupping noted, as they approach the 6Kmile mark.

I plan to get PR3's installed this summer based on feedback from this forum even though I won't wear these PR2's out by that time. It's a cost of planning for the cross country rides I hope for this summer. I put new ones on before I leave to minimize down time enroute.

I've considered a steering damper too. I'll watch for feedback on that along with you.

 

[Rmcapozzi]

Uneven tire wear is a likely reason. But don't neglect checking the condition of the rear tire. It too can cause front end shaking.

here's a new one!

When I slow down from around 45 to around 40, the front end shakes.

It's smooth at speed, no issues at all.

Ideas??

 

[Lorien]

It would be useful to know if this is a a hands on the bars shake which I am assuming. Lots of bikes will shake the front if you slow down hands off or very light hand pressure. Just the nature of the beast some more than others. As many have said the most likely culprit is the front tire. Now the BS 020 is a very soft rubber. Under inflate it and it can go south very quickly. My personal opinion is this is a combination of the tread pattern and the soft compound. Mine showed excessive wear by 6k and I tend to be conservative in my application of power, brakes corners, etc
After the tires the head bearings are worth the inspection. I doubt it after so little milage but they could not be properly torqued to begin with.
Something not mentioned is the forks. It is possible that a slight bend caused by contact can really get the front to shake. This is probably the last thing I would look at but has happened. The evaluation can be complex.

 

[Phil Tarman]

It was common on Kawasaki Concours (especially those made in '99 for some reason) for there to be a hands-off-the-bars deceleration shake between 40-30 mph. This would gradually worsen so that hands-off deceleration shaking occured at any speed between 55-60 on down to about 20. At least with my bike, it was the result of head bearings that needed to be tightened by nearly a half turn. After making that one adjustment, that bike didn't show any shaking with the same original head bearings at 115,000 miles. The shake showed up fairly early, would improve when I replaced the tires, but would be evident with no visible cupping. I finally adjusted the head bearings at about 30,000-35,000 miles and that ended it.

 

[Chucksklrst]

Most likely tires, How many miles on the tires? If not tires maybe the steering head bearings need to be re torqued. I have replaced my OEM tires with Avon STorm II's and have had no issues with head shake. Either with the OEM or the STorm II tires.

 

[Phil Tarman]

The only time I've noticed any head shake on the NT was once at 35 about two days after I put the PR3s on the bike. It never happened before (even with a cupped OEM BT-020 at 6,000 miles) and it's never happened since.

 

[loonytuna]

I have kept the tire properly inflated.

I have had a lot of bikes, maybe I have been lucky, but not since the early days of mediocre frames etc have I felt any shake to speak of.

This is noticeable with light pressure and of course if I take my hands off it's worse, but it also is only in a very small window (speed), and again the bike is perfect at speed.

After everything I have read about these tires, I would not be surprised if they are already cupping.

I'm tempted to change the tire, it will only cost around 150 to do that and it's not the best diagnostic, but I'd be getting an improved tire anyhow so that's what I'm thinking right now.

 

[WVRider]

I first noticed a wee bit of shake, only when really light handed on the bars during slow down, at 2500 miles on the original tires. I already have 3200 miles on my PR2's and absolutely no shake even when I release the pressure from the bars (hands off) to test. It will always show up first at 30 to 35 mph when slowing.

 

[loonytuna]

DJ

Sounds exactly like what I have - gotta be the OEM tires.

Thanks!

Randy