High Speed wobble

[Tom Iddings]

In the last few months, friends have commented that I seem to have a rear wheel wobble on my 1947 Chief. I've checked true, spokes etc. nothing is out. There is a slight movement side to side on the axle of about 1/32".

On the highway Sunday at 75 mpm, it wobbled side to side severely enough to wipe out a lesser rider.

Does anyone have any idea what it could be?

[AdminGuy]

check bearings?

[brian_groff]

The side to side movement isn't a terribly big deal unless you're running Timken style bearings. If you are running Timkens, you've got bigger issues.

First thing is to check your head out, because if your friends notice a wobble before you do, you might have a screw loose.


Next, check your head bearings (for real). They need to be tight. This is the root cause of most high speed wobbles. I am talking about the tripple tree here.

How are you checking to see if your wheels are true? If you're not measuring with a dial axially and radially, then you might not be getting a true picture. Most people measure side-to-side movement in thousandths of an inch. Tolerances on wheel trueing, if I recall correct, is .020" TIR radially, .030" TIR axially. This can be adjusted on the bike, but it's more difficult than if it were in a trueing jig.

If you're going to ride it 75+, balance your tires This makes a HUGE difference! You will need a special adapter to make it fit on today's balancing machines. PM me if you need a hook-up on this. I run Avon Gangster White Walls on my '47 and I balance the tires the same way I do on my 2003 Chief. Static balancing the old way with soldering wire just doesn't do it anymore.

[Tom Iddings]

I'm sure I have a screw loose! The only time my friends notice it is when I'm accelerating briskly...shall we say.

I don't think it is the head, but will definitely check it. I know the old girder is a bit worn but not that bad.

Frankly, I haven't wanted to take the rear wheel of to replace the bearings and I suspected that the recent increase in ride vibration was originating in the rear.

Well, I guess that settles it. The wheel comes off tomorrow. Thanks guys.

Oh, by the way 75-80 she purz right along, must be the shunk cams and boneville carb. When she's ready I figure a kiwi 84" kit is in order. :

[brian_groff]

One more word ...

LOCTITE

on the rear lug nuts ... always ... else you'll be walking. The BLUE STUFF too! (Use RED for seating the studs into the drum).

Of course, you knew this already

ALSO ... last thing I promise ... check the retaining nut in the brake drum! This has been a source of side-to-side movement in the past. It's left hand threaded, should be secured by a cotter pin, and benefits from having some RED Loctite applied on the threads.

[Paps]

This might be off the wall a bit but did you balance your tires ? Paps

[AdminGuy]

I'm interested in seeing a picture or info about the adapter for highspeed balance jobs. Thanks.

[INLINE4NUT]

I hope you let us all know what it was so we all can store it for future referance thanks !

[GeeS&K]

wobble

Have you checked the tire bead? Or the lug nuts? If you've trued the wheel and spokes and it's not a bearing, it might be something as simple as the tire needs to be rebeaded. All the balancing in the world won't fix it if the bead isn't right.

[Lonnie]

Check the runout in the tire itself once it is mounted on the wheel. In addition, I've seen cases of vibration and poor handling with defective NEW tires. And I've noticed that the original air pressure specs do not seem to be valid for my reproduction Coker tires. I'm having to run higher air pressure to get an acceptable wear pattern, expecially in the front.
Lonnie

[KNUCK]

Ditto on the rear tire runout, even if it is new ! You could be in for a surprise.

[djohnson]

high speed wobble

this might not apply to an Indian, but on my wife's U and WL, loose motor mount bolts caused a speed wobble at 75 or so.
Doug

[Kiwi Mike]

Check steering head berings, fork bushings (46-48 models) wheel bearings, rear drum bearing (take wheel off to check properly), rear shack bushings for a start. Generally the wobble you are explaining comes from the front end.
Mike Tomas
Kiwi Indian MotorCycle Co