Author Topic: Twitchy tires  (Read 726 times)

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Offline Danny sparks

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Twitchy tires
« on: October 13, 2017, 10:04:48 am »
 When I purchased this bike it’s had brand-new tires on it.Avons  storms ....iam just not happy with the  feedback and twitchiness.....or is it just me

Offline Pbfoot

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Re: Twitchy tires
« Reply #1 on: October 13, 2017, 12:36:51 pm »
Imho the only cure is a 17 inch conversion using Dunlop Roadsmart 3 tires. The tires available for the stock rims are crap. The conversion will pay for itself over the long term as 17 inch tires are cheaper.
If you don't have time to do it right, when do you have time to do it over.                                                                17" wheels, Nissin 4 piston calipers.1kg Sonic Springs.Cartridge Fork Emulators. KB Brace. Galfer brake lines  Free power mod.

Offline Daytona_Mike

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Re: Twitchy tires
« Reply #2 on: October 13, 2017, 12:42:02 pm »
Fast turn in  or what you are calling Twitching  has to do with your sag settings or the chassis ride height (which is the same thing). The front is too low or the rear is too high.  Read up on how to adjust your pre-load adjusters . You may have too much air in the rear shock which raises the rear too much. In any case your chassis geometry is off. Raise the front to make it less twitchy.
Its not your tires because those are very good tires- I ran that bike on track days with those tires.
Normally aspirated engines have perpetual turbo lag
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Offline GeorgeRYoung

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Re: Twitchy tires
« Reply #3 on: October 13, 2017, 12:48:00 pm »
What is twitchiness for some is responsiveness for others.

Offline Cal

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Re: Twitchy tires
« Reply #4 on: October 13, 2017, 01:30:24 pm »
my last set of tires were the Storm variety.  I was extremely pleased with their confidence in wet or dry, overall responsiveness when turning or over in a curve was terrific.

I had just done some work on the front end (full removal of forks/disassembly/new steering head bearings/etc - so that may have a lot to do with the overall outcome)

I also have the shock from a ZG1400 installed - so it sits about an inch+ higher.

I weigh about 200lbs and always have the side bags on with some assortment of stuff in them - to give an idea of load.

I wave just recently replaced the Storms with the Avon X-3D? again - really stable in use (initially thought the turn in was quicker but got used to it).  !ad to replace them because I went to Cape Breton and rode the back roads extensively for a week - some really rough pavement mixed with pristine stretches - almost always over in a curve.  I wore through the sidewalls!!!  pictures of the cords for the asking!

I do notice the X-3D front seems to track tar strips a little to closely at times.

IMO those tires were a good set for me (1986 C10 180,000+ km)

Cal

Offline Bob_C_CT

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Re: Twitchy tires
« Reply #5 on: October 13, 2017, 02:33:39 pm »
I had the storm on mine before I switched to 17" and PR4s, was happy with the contact with the road, wet or dry but wear faster than other "harder" tires.
Do you know how many miles are on them?
Mine wore a little funny on the rear and started to get a little hopping issue in the rear tire at half treadwear.

I think you have to describe twitchiness a little more and give conditions when you feel it, speed, riding conditions, curves, highway, etc

You may want to get the tire raised off the ground and give it a spin by hand to see if you can see any issues with runout, axially or radially or any other noticeable issues.
97 C10,ZRX Front, Meanie Rear

Offline Danny sparks

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Re: Twitchy tires
« Reply #6 on: October 13, 2017, 07:06:16 pm »
I have so far fitted a c14 rear shock replaced all the linkage bearings .fitted yss front fork  Valves also increase the spaces to get preload on the forks...all other bearings checked and greased.iam starting to think that it might be the rear ride height.Altering the rake on the forks...so maybe a lowering kit is next....this Bike had 101 issues when I got it but slowly but surely  I’m working through them...

Offline Danny sparks

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Re: Twitchy tires
« Reply #7 on: October 13, 2017, 07:11:19 pm »
As for the bike being twitchy it just feels uneasy when overtaking large lorries ...and also when on the overrun when slowing down...it’s fine when running flat out up to about 120mph...just Cruising it has  issues ...it goes around corners great...

Offline Cal

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Re: Twitchy tires
« Reply #8 on: October 13, 2017, 07:54:55 pm »
I mentioned that I had done the head bearings - which initially felt fine but I eventually began to feel a wobble around 60-70 km/h mark that required both hands on the bars for acel or decel (usually the speed I am using left hand to drop the helmet visor!!!)

once I tightened down the bearings an 1/8 to 1/4 turn all wobble was gone and I could relax when riding again.   :)

I would like the rear to be back down to 'normal' ride height since I added the ZG1400 shock - but have yet to find a lowering kit that seems to work without other issues being mentioned by the group.

maybe I have acclimatized to the added rear end height.  certainly contains my and my wife of 35 years added baggage without issue  :'(

Cal

Offline Daytona_Mike

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Re: Twitchy tires
« Reply #9 on: October 13, 2017, 10:36:59 pm »
As for the bike being twitchy it just feels uneasy when overtaking large lorries ...and also when on the overrun when slowing down...it’s fine when running flat out up to about 120mph...just Cruising it has  issues ...it goes around corners great...


Well heck- the word  twitchy can  be many different things- this time it means something totally not what I would have thought. 
I think over here on this side of the pond we would call  what your describing as 'dirty air' where as  the wind coming off of a truck when passing  will  buffet the bike.
I thought these bikes where good  and stable in dirty air due to their weight and aerodynamics.  I don't think tires  or preload has a whole  lot  to do with buffeting.
Maybe take a light weight 250cc bike  and pass a few trucks to get used how much worse it is on those bikes. Then you will love the GTR   
What happens after 120?  Flat out here is about 170mph?
 
« Last Edit: October 13, 2017, 10:46:02 pm by Daytona_Mike »
Normally aspirated engines have perpetual turbo lag
2000 Red C10 1052 kit
2008  C14 Silver Dammit Full AreaP- Flies are put back in SISF_Flash
2011  KLR650   688 piston ported and polished
2011  KTM 530    This thing is FUN!!

Offline Bob_C_CT

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Re: Twitchy tires
« Reply #10 on: October 14, 2017, 08:30:47 am »
I agree the stock C10 will experience some/a lot of buffeting in dirty air. I think the stock windscreen adds to this.
Check your motor mount bolts too.
When I got my bike I had very bad wandering in dirty air (felt like riding on marbles)when passing trucks on the highway ended up that my lower engine mount bolt was sheared off.
97 C10,ZRX Front, Meanie Rear

Offline Danny sparks

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Re: Twitchy tires
« Reply #11 on: October 14, 2017, 12:34:07 pm »
As for the bike being twitchy it just feels uneasy when overtaking large lorries ...and also when on the overrun when slowing down...it’s fine when running flat out up to about 120mph...just Cruising it has  issues ...it goes around corners great...


Well heck- the word  twitchy can  be many different things- this time it means something totally not what I would have thought. 
I think over here on this side of the pond we would call  what your describing as 'dirty air' where as  the wind coming off of a truck when passing  will  buffet the bike.
I thought these bikes where good  and stable in dirty air due to their weight and aerodynamics.  I don't think tires  or preload has a whole  lot  to do with buffeting.
Maybe take a light weight 250cc bike  and pass a few trucks to get used how much worse it is on those bikes. Then you will love the GTR   
What happens after 120?  Flat out here is about 170mph?
yes you could be right  with dirty air....But as for aerodynamics it reminds me of a melted welly



Offline GeorgeRYoung

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Re: Twitchy tires
« Reply #12 on: October 14, 2017, 01:14:23 pm »
. . .  Flat out here is about 170mph?
Cycle World reported the top speed of a C10 was 125mph. You must have a very special Concours.

Offline connie_rider

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Re: Twitchy tires
« Reply #13 on: October 16, 2017, 06:28:08 pm »
Danny, a friend of mine had the 3D-XM's on his Connie.
When he would pull up behind a truck the rear would squirm so badly I could see it while riding behind him.
He tried various things, but eventually got rid of the tires and the problem went away.

On your C-14 shock, adding a Norm Soucy Lowering Rocker will set the bike at whatever height you want.
The rockers are made in various heights.
I think most use a 1 1/2 rocker.

Ride safe, Ted
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Offline Cal

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Re: Twitchy tires
« Reply #14 on: October 16, 2017, 07:29:24 pm »
C_R

"On your C-14 shock, adding a Norm Soucy Lowering Rocker will set the bike at whatever height you want.
The rockers are made in various heights.
I think most use a 1 1/2 rocker."

got anything more specific like a link on that?  last I read I thought those lowering kits were for the original shock - and the 1400 shock spring got in the way.

Cal

Offline Daytona_Mike

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Re: Twitchy tires
« Reply #15 on: October 16, 2017, 10:12:35 pm »
. . .  Flat out here is about 170mph?
Cycle World reported the top speed of a C10 was 125mph. You must have a very special Concours.
Yeah, I thought this was a C14 forum so wrong bike.
 I had my old  C10 up to 135mph but that was all it had
Normally aspirated engines have perpetual turbo lag
2000 Red C10 1052 kit
2008  C14 Silver Dammit Full AreaP- Flies are put back in SISF_Flash
2011  KLR650   688 piston ported and polished
2011  KTM 530    This thing is FUN!!

Offline Bob_C_CT

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Re: Twitchy tires
« Reply #16 on: October 16, 2017, 11:14:33 pm »
The norm soucy lowering link rocker will work with all shocks. Might have to modify the shock mounting hole on the link for a non oem shock.
 What Cal is thinking of are the adjustable shock linkage with tie rod ends that are adjustable that get in the way of the spring.
97 C10,ZRX Front, Meanie Rear

Offline Mcfly

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Re: Twitchy tires
« Reply #17 on: October 16, 2017, 11:51:53 pm »
Norm's 1.5 inch lowering rocker puts the back end very close to stock.  Iffin' ya can find one it's
the best solution I found with the C14 rear shock.  The center stand binds on the suspension if you
don't stand it upright before deploying it, but that's no real bother.  As mentioned, the adjustable lowering
Links are no go with a C14 shock... the spring is too wide and hits the links

If you've recently done work to the steering stem, go back and check it if you haven't done so.
As time passes, things compress a bit, leaving enough to make buffeting tedious.  I did mine 3x
before I got it right.

New Avon 3D-XMs are twitchy to me, but only until they wear a bit, then they're a super stable tire.
Performance -- Rear: C14 Shock - Front: Sonic 1.1 w/emulators - SISF Jet Mod & Ex Cam Sprocket - Tokico front brakes
Comfort -- Russell Day Long - Madstad - Cruise Control

Offline Cal

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Re: Twitchy tires
« Reply #18 on: October 17, 2017, 12:19:28 pm »
Mcfly

"The center stand binds on the suspension if you
don't stand it upright before deploying it, but that's no real bother. "

so - nothing interferes while riding - just something one has to push through when standing up on the centre stand itself?

Thanks

Cal

Offline connie_rider

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Re: Twitchy tires
« Reply #19 on: October 17, 2017, 01:59:11 pm »
Norm's 1.5 inch lowering rocker puts the back end very close to stock.  Iffin' ya can find one

Some time back, I located and contacted Norm. He's still making the links.
I'll try to find the info on how to reach him. See next post.

On the other Forum there is a discussion about high speed wobble. The solution was to replace a defective rear 3D XM.

Ride safe, Ted

« Last Edit: October 18, 2017, 02:50:11 pm by connie_rider »
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Offline connie_rider

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Re: Twitchy tires
« Reply #20 on: October 17, 2017, 02:11:43 pm »
Norm Soucy Lowering Rocker info from old discussion;

I thought that the Lowering Rocker that Norm Soucy made {for the C-10} was no longer available.
So I located him.  :great:

{Has the 1 1/2" in stock}  Said he can make different heights.
   (He now puts new bearings in all Lowering Rockers and sells them for $200)

We briefly discussed the use of his Lowering Rockers and Longer shocks.
I told him, that people would be interested in his Lowering Rockers because of installations of C-14 (or other) shocks.
  He estimated that;
    A C-10 (with a C-14 shock and his 1 1/2" Lowering Rocker), the bike would set 1/2" lower than stock.
    A C-10 (with a C-14 shock and his 1" Lowering Rocker), the bike would set the same height as stock.

If this is of interest to anyone , contact him.

Here is his up to date info:   sanleonster@gmail.com
                                          phone# (281) 339-1156

Ride safe, Ted
« Last Edit: October 17, 2017, 04:07:44 pm by connie_rider »
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Offline Mcfly

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Re: Twitchy tires
« Reply #21 on: October 17, 2017, 03:41:26 pm »
Mcfly

"The center stand binds on the suspension if you
don't stand it upright before deploying it, but that's no real bother. "

so - nothing interferes while riding - just something one has to push through when standing up on the centre stand itself?

Thanks

Cal

That’s correct.  Just a matter of standing the bike upright before pushing down on the CC lever.  The ride isn’t affected at all.
Performance -- Rear: C14 Shock - Front: Sonic 1.1 w/emulators - SISF Jet Mod & Ex Cam Sprocket - Tokico front brakes
Comfort -- Russell Day Long - Madstad - Cruise Control

Offline Cal

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Re: Twitchy tires
« Reply #22 on: October 17, 2017, 04:01:55 pm »
thanks C_R and Mcfly.  will look into a winter upgrade now!

again - FWIW - bike rides fine but would like it a bit lower on the rear.

Cal

Offline Mcfly

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Re: Twitchy tires
« Reply #23 on: October 17, 2017, 09:22:26 pm »
Norm Soucy Lowering Rocker info from old discussion;

I thought that the Lowering Rocker that Norm Soucy made {for the C-10} was no longer available.
So I located him.  :great:

{Has the 1 1/2" in stock}  Said he can make different heights.
   (He now puts new bearings in all Lowering Rockers and sells them for $200)

We briefly discussed the use of his Lowering Rockers and Longer shocks.
I told him, that people would be interested in his Lowering Rockers because of installations of C-14 (or other) shocks.
  He estimated that;
    A C-10 (with a C-14 shock and his 1 1/2" Lowering Rocker), the bike would set 1/2" lower than stock.
    A C-10 (with a C-14 shock and his 1" Lowering Rocker), the bike would set the same height as stock.

If this is of interest to anyone , contact him.

Here is his up to date info:   sanleonster@gmail.com
                                          phone# (281) 339-1156

Ride safe, Ted

Thanks Ted!  You da man!  My shock went in back in 7/2014, so my recollection
Is sketchy.  I now know I used a 1.5 in ( I looked back at the thread) for certain.
The C-14 shock with the 1.5in rocker has put the bike's rear height back to the OEM
shock's height w/ 7 clicks on the adjuster.  I have it all written down in the back of my
shop manual from the install...  I go to 15 clicks 2 up.
Performance -- Rear: C14 Shock - Front: Sonic 1.1 w/emulators - SISF Jet Mod & Ex Cam Sprocket - Tokico front brakes
Comfort -- Russell Day Long - Madstad - Cruise Control