Finally, a problem with a CT

Still playing with pressures on the Vredestein 175/75/16, on the Heritage, running solo. I was at 32 psi and hit the new interstate where they rain-grooved it lengthwise, and it started oscillating back and forth enough at about 68 and above to give me major pucker factor.
Gripping the bars made it worse; some went away when I held my arms up and let the fingers just touch the grips.
Countersteering within my lane made it go away.
Hitting the asphalt made it go completely away.

I dropped the pressure to 30 and tried the same stretch; it got worse, so it's back up to 34-36 for me.
This is a trade-off, because she likes the medium twisties at low pressure best. But I can't take chances on an oscillation taking off on me. I can just picture how badly that might go.

I know this all comes under the heading of finding a sweet spot, but it's something to warn about, IMO.

Thanks for the heads up.

Jerry

Aint no world perfect! Thanks for the heads up, I have not encountered that type of slab of grooved road yet.

IMO try a higher pressure. 30 PSI is not enough pressure for anything. Id start at about 36 and go from there.
Thanks for the heads up. Im running a 215 and my sweet spot is 37 psi.

Thanks for the update. Keep us informed as to your findings.
Peace
Moon

I think it is more of a problem because of your skinny front tire,I encountered that on my goldwing but is not a problem with the nomad with the wide front tire.

I've gone from 40 lbs. down to the 30, and now back up to the 36. Had the lady on tonight to go to bike night and it felt perfect.
Front is the 130mm Dunnie, and it didn't do that with a MT on the back; it was the low pressure in back doing it.

Now I'm confused. It did it again today (I-75 grooves) and we made another run at 40 psi - it was less but still there. I'm beginning to think this Comtrac just doesn't like the grooves at all. I had lowered my front psi to 38; maybe I need to put it back up to 40? I'm tempted to hit the back up to 42 and see what that does, but I'm not sure that won't take away from cornering or lessen my contact patch.
I guess I'll just have to keep changing things until I find where it works, but the 36 was the best for the twisties. If I put that up, and we hit grooves somewhere, I have to go like 60 mph or it's really uncomfortable. Scared the crap outta the ol' lady today.
How come I'M the only one with a problem? Just my luk.

You are not the only one that has had this. I have been running the 165-80-15 for years now and noticed it on one of the highways I ride to work on. It never did get bad, it was just annoying. Like you found out, I just relaxed my grip on the bars and rode through it. I feel it in my little car also and I run 195s on it, I think. Car just wants to wander a little while in the rain grooves. Does it get any worse or better if you change lane position? Any better or worse on one section of the road or other. The only thing I can relate what you are describing is riding over a steel grated bridge. The first time I did this out in Newport News I about crapped myself. The front was going one way and the rear another.

Good Luck,
Db

Now you mention it, it's very much like the steel bridges I'd ridden over years back. (ain't none here) And it's bad enough to ruin your ride, scary enough to make you pucker, wondering if it's gonna get worse. Has to look ridiculous from behind too.
They grooved it so deep, there is no "sanctuary" strip anywhere in the lanes. I almost wanted to get on the dang shoulder, but that's a ticket here and traffic would be passing by you while you ride amidst their trash.
I'll try higher pressure tomorrow if it's not raining.

The problem went away on mine by dropping the pressure.

Well, I TRIED lower pressures down to 30 where it got sick, and back up to even 40 with it STILL wobbling!
So I put her up on the jack and fired that mutha up, kicked her into 1st and watched the tire. It's about as
perfect as any tire I've ever seen spin. BUT...every time the Harley did the Harley idle "lope", something seemed to
jump back there, and I thought suspension at first.
I shut her down and guess what? The WHEEL is comin' apart! Almost all the spokes were loose, and I'm lucky the hog
has short, thick spokes or this could have been a disaster with my wife on the back.
As a longtime bike rider, I have no excuse for not checking spoke tensions. I'll not be remiss again!

Now I know it's NOT the tire, and I have to recalculate pressures again - probably go back to 32 and work up.

Sure glad it turned out alright for you and yours ,that is just plain scarey.

WOW! only thing I've heard of worse than that is a buddy of mine with a 93 Heritage Special (I think it is), he's had 2 rear rims split on him! Although he did turn that bike over 250K miles this past week while visiting for Sturgis....

quadancer wrote:Well, I TRIED lower pressures down to 30 where it got sick, and back up to even 40 with it STILL wobbling!
So I put her up on the jack and fired that mutha up, kicked her into 1st and watched the tire. It's about as
perfect as any tire I've ever seen spin. BUT...every time the Harley did the Harley idle "lope", something seemed to
jump back there, and I thought suspension at first.
I shut her down and guess what? The WHEEL is comin' apart! Almost all the spokes were loose, and I'm lucky the hog
has short, thick spokes or this could have been a disaster with my wife on the back.
As a longtime bike rider, I have no excuse for not checking spoke tensions. I'll not be remiss again!

Now I know it's NOT the tire, and I have to recalculate pressures again - probably go back to 32 and work up.

That is the one biggest reason I will never have a spoke wheel ever again. Same thing happened to me years back. The mag wheels are so much easier and the look is awesome. JMO. Glad you caught it.

Peace
Moon

I thank GOD for that one...I was just sorta "led" to the stand test, which I was nervous about doing - a lot of torque on a bike just
up in the air on it's engine frame. Not the first time He put me to an answer I needed, and protected me and mine.

Sure glad you figured that one out. After reading your initial post, I was having 2nd thoughts about mounting my 1st CT - which should arrive tomorrow (Comtrac-V5005 175/75R16). I don't run spokes, and wouldn't - just because I know I'd forget to check them just as you did. They might look old-school and cool, but just another thing to maintain that I don't need IMHO.

quadancer wrote:I thank GOD for that one...I was just sorta "led" to the stand test, which I was nervous about doing - a lot of torque on a bike just
up in the air on it's engine frame. Not the first time He put me to an answer I needed, and protected me and mine.

All glory to God. It could have ended badly if he wasn't watching out for you.

Jerry

my sweet spot is 45psi

Then you're not running a Comtrac, that's for sure. It's all "feely" at 40 or above.