Handle bar wobble with new tires

[red bandit]

I installed and balanced both new tires and now notice a wobble in the handle bars between 20 & 30 mph. I couldn't upload the video on this site so I did on FB. I know you guys love that. Any way does this look like enough tire sway/wobble to affect the handle bars? Thoughts?

https://www.facebook.com/10000212588...3621462518457/

[Bax]

Specials.... Did you center the rotor in the fork cutout on the right side before tightening the pinch bolt? Didn't view the video yet.


---Bax

[red bandit]

I had the calipers and all the brake pads off when I tightened the axel nut and then I centered the rotor between the cut out as I tightened the pinch bolts.

[DiverRay]

When was the last time you checked the steering stem bearings? If the bike had been sitting in one place for a few years, you get flat spots on the race! I know that from my special, 22K miles and needed new bearings.

[bikerphil]

I couldn't upload the video on this site so I did on FB

Can't see the video even after logging in, this message appears...

This Content Isn't Available Right Now
When this happens, it's usually because the owner only shared it with a small group of people, changed who can see it or it's been deleted.

Does your 79F have a tube in the front tire? Reason I ask is sometimes the tire doesn't get fully seated, check the line on the tire that is right next to the rim to see if it is even all the way around.

[red bandit]

Steering stem bearings were new a few years back. It only sits through the winter. I changed my privacy setting on FB. You should be able to see it now. No tube in front. Wheels are fully seated as indicated by line on sidewall, both sides. I added a video of both side walls.

[cajun31]

Steering stem bearings were new a few years back. It only sits through the winter. I changed my privacy setting on FB. You should be able to see it now. No tube in front. Wheels are fully seated as indicated by line on sidewall, both sides. I added a video of both side walls.

Still can't see the video. Same error message that Phil pointed out.

[red bandit]

Ok. Don't know what I can do about that.

[red bandit]

https://www.facebook.com/jim.sisler.5/

[bikerphil]

I see the videos now, one of them is more steady than the other and that one doesn't look like it would cause a problem. When is the last time the forks were serviced? Also, were the rotors taken off when changing the tire?

[red bandit]

I haven't changed the fork oil in several years. The rotors were not taken off.

[bikerphil]

Reason I ask is I've ridden bikes with sagging forks that had a type of wobble you describe. Maybe time to refresh the oil and add some spacers to tighten up the springs a bit. If there is a large amount of sag, it may be causing/part of the problem.

[JeffH]

Sorry to hear you are having an issue with the new tires. Certainly not what you were expecting after all that work.
Like yourself and the other guys reading this thread, I've been pondering what could be the cause.


I happened to go back and read your Its Time for Tires thread.
8/2: I have used the Spitfires before and that's what's on it now. They cup and cause a vibration and my hands go numb that's why I'm going with the Shinkos. I was going to wait until winter to do tires but the rear show some cords in two spots

It seems if the bike rode great with the old Spitfires that the issue could be maybe you got a bad tire. I've had a couple of those over the years. Manufacturing defect.

But it seems from 8/2 that there likely has been something going on. And the new tires just manifest it differently.

A few things normally cause cupping. Lots of miles with improper tire pressure is usually a big one. But in your case that's not it. Same with really hard race riding and hard braking in curves. Phil and Ray are likely onto the issue. Something with suspension. If you are riding a bouncing pogo-stick then I'd think that would cause cupping. As Phil mentioned forks could possibly be the culprit. Or POS shocks.

Just trying to think though why the wobble or vibration would still be showing up with the new tires. But maybe something wasn't quite right all the miles you were running the Spitfires.
I was on the path of bad tire but after reading 8/2 it seems like something suspension related.

Jeff

[red bandit]

I put NOS front springs on a couple years ago. I'll change the fluid and see if I can add some preload to them. I've had 2-3 of the spitfires. They all ran good but cupped at about 10,000/12,000 miles. I don't do the twisties or hard braking while corning. With a fairing I get plenty of sag. I try to keep the tire pressure up. I wanted to check with you guys before I send the tire back and claim it's defective. Thanks for all your help.

[bikerphil]

I'll change the fluid

I would use at least 15W instead of the 10W the manual suggests.