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Author Topic: Running wide in corners  (Read 3110 times)
Two dogs
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« on: August 02, 2009, 01:38:45 PM »

I have noticed lately my bike wants to run wide on corners at higher speeds Shocked
This is after a upgrade of fully adjustable front forks and harder spring in the back , it is only a subtle thing but still a bit concerning.

I pay a lot of attention to body position so my feeling is it may be something more likely with suspension,
I had been running a PSI that was too low bang head (which I have increased to 36-38 )contributing towards excessive ware maybe this could be a cause as the steering feels a little vague.
New PP's tryes coming soon applause


If it is suspension what should I look at changing to get my radius tighter on exit or am I getting lazy with technique or just to fast on exit ?

Any contribution would be appreciated .
« Last Edit: August 02, 2009, 01:41:50 PM by dezmonster » Logged
Betty
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« Reply #1 on: August 02, 2009, 01:47:47 PM »

I, as usual, don't know what I am talking about but I am willing to talk some shit anyway.

Sounds like the changes you have made (both suspensions and tyre pressures) have just changed the bike in ways that your riding has not yet been able to fully adjust. If you think the changes are right (tyre pressures are higher than I run, especially the front) maybe you just need to give yourslef some more time.

Either of these changes independently I would reckon would have a significant enough change on the 'feel' of the bike ... combining them may have just thrown you out a little more than you were expecting.
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CairnsDuc
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« Reply #2 on: August 02, 2009, 01:50:13 PM »

I would drop that tyre pressure a bit, I used to run 36 PSI in my Tyres, but when I dropped it to 32PSi it would feel better in the corners, it was explained to me when the tyres are running such high pressures, your contact patch becomes smaller, less rubber on the road means less grip.

When you changed the spring, did you get the shock setup for the new spring?
Did you get the forks setup for your bike, weight and riding style?

Suspension setup can be a little tricky, just because you have new suspension bits front and rear, and they may be better than OEM, you have to ensure they are setup for you and your bike, I have seen some guys make there bikes and cars handling worse, by installing new and expensive suspension parts and then not having them setup and tuned for there situation.
I would suggest talking to a bike suspension specialist, and see what they suggest.

I will say, when I changed my rear Showa to an Ohlins, setup for my weight and riding style, it made the bike really twitchy, but because the forks were still stock, the bike was now out of balance, after consulting the Guys at Promecha in Melbourne, I changed the fork springs and put in new oil and changed the oil height, the bike was a new bike, it was on rails!
 
Suspension is all about balance, you adjust one end, it will affect the other end also!
If you make changes, do it one step at a time, make a note in a diary, It took me about 3 to 4 weeks of little adjustments to get my bike right, I'd make a change, make a note of how it felt, then make another change, make a note.
but don't go to crazy when making adjustments, take it easy and take your time.
« Last Edit: August 02, 2009, 01:56:30 PM by CairnsDuc » Logged
Dockstrada
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« Reply #3 on: August 02, 2009, 01:57:48 PM »

Normally after adjusting the suspension people seem to think the bike will be easier to ride, most cases true but it can also exposes you bad habits.

Did you have the suspension adjusted to fit you. Huh?

Are you going to fast  Huh?

Are you backing of the throttle at any time through the bend Huh?

Backing off the throttle will run you wide at high speed as it will stand the bike up. you should enter the bend at the speed you are happy to continue through it without any throttle position change. Normally if you enter the bend at a given speed and hold the throttle position the bike will naturally slow down as you are using a larger radius of the tire when you lean the bike onto the side of the tire .

Are you using any rear brake  Huh?

using slight rear brake will pull the bike tighter into the turn.

Are you target fixating  Huh?

I think we all know what happens here.

Have you chosen the wrong line  Huh?

Try a later apex when entering the turn it will position you on the inside of the bend on exit and give you some margin for error .

 waytogo

There is a link on the the oz-monster site with some more information. waytogo

 http://ozmonster.org/index.php?view=items&cid=1%3Amotorcycle&id=5%3Ariding-safe-techniques&option=com_quickfaq&Itemid=24


« Last Edit: August 02, 2009, 02:01:02 PM by Dockstrada » Logged

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« Reply #4 on: August 02, 2009, 02:29:19 PM »

First things first.............

Did you redo the static ride height once everything was back together?? Huh?

Just chucking stuff back in just wont work. Shocked

Remember, go back to square 1 and do 1 thing at a time and write it down with the result......better or worse and how it was better or worse., Grin

There is also a phsychological aspect of not being happy/confident on the bike. If you arnt happy with the handling you are likely to stiffen up coming into a corner and steering becomes harder. The bike starts to feel like its running wide and your eyes then run to the outside to where you DONT want to go and you DO run wide.
People who arnt confident will by nature drop their eyes and that will screw up your ability to relax and feel comfortable and confident. Bad data.

Relax and keep your eyes up and looking to the path you want to take and you'll be more able to feel what the bike is doing. waytogo
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« Reply #5 on: August 02, 2009, 03:40:10 PM »

Normally after adjusting the suspension people seem to think the bike will be easier to ride, most cases true but it can also exposes you bad habits.

Did you have the suspension adjusted to fit you. Huh?

Are you going to fast  Huh?

Are you backing of the throttle at any time through the bend Huh?

Backing off the throttle will run you wide at high speed as it will stand the bike up. you should enter the bend at the speed you are happy to continue through it without any throttle position change. Normally if you enter the bend at a given speed and hold the throttle position the bike will naturally slow down as you are using a larger radius of the tire when you lean the bike onto the side of the tire .

Are you using any rear brake  Huh?

using slight rear brake will pull the bike tighter into the turn.

Are you target fixating  Huh?

I think we all know what happens here.

Have you chosen the wrong line  Huh?

Try a later apex when entering the turn it will position you on the inside of the bend on exit and give you some margin for error .

 waytogo

There is a link on the the oz-monster site with some more information. waytogo

 http://ozmonster.org/index.php?view=items&cid=1%3Amotorcycle&id=5%3Ariding-safe-techniques&option=com_quickfaq&Itemid=24


Suspension was set up for the bike by Motorcycle weaponry and on first riding felt really good.
After reading everyones input I am thinking maybe a combination of the higher PSI
and higher speed may be a large portion of the problem.
Yes I trail the rear and target fixation doesn't seem to be an issue
Maybe joining in on a group ride with some of you guys may help as I am usually riding by my self so following riders into corners may help and being followed and watched and talking about it after.
I originally was running around 32-34 psi but was told that was to low and contributed to early tyre ware , I will back it off and see if that helps.
And thanks for the input , if anyone is up for an Old Pac ride soon would love to tag along put a call out for a Saturday morning or even a early weekday ride as I only work nights.
cheers
dez
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« Reply #6 on: August 02, 2009, 04:19:03 PM »

I don't doubt that a higher tyre pressure would reduce wear (probably improve your fuel economy too) ... but you need to find the right balance for you and the way you want to ride.

Gross simplification:

Lower pressure = greater contact patch = more grip = faster wear

Also:

Higher pressure = lesser contact patch = less friction = less grip = less wear

I have joked in the past about putting higher pressures in Jukie's bike to make the bike a little skittish/nervous and slow her down ... but it just makes her quicker as she has less rolling resistance  laughingdp

Agree that confidence in everything (the right combination) is a key contributing factor ... and also why I am so slow Grin
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« Reply #7 on: August 02, 2009, 07:13:28 PM »

Dez I might be out for a little blat this Saturday will drop you a line later in the week to let you know.
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« Reply #8 on: August 02, 2009, 07:38:01 PM »

Dez I might be out for a little blat this Saturday will drop you a line later in the week to let you know.
Sweeeeeeeet  applause weather looks good for Sat and keen for a look at the new hot mix on the Old road
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« Reply #9 on: August 03, 2009, 12:16:19 AM »

With a harder spring on the front, as the spring compresses less when you're leaned over the bike will have a slower steering response. Any chages to spring rates will have a big effect on steering geometry under load.

As for:
"Higher pressure = lesser contact patch = less friction = less grip = less wear"
how does a tyre slipping on the road due to less grip mean less wear?
Don't make sense.

You do get more heat and more wear in a tyre when its under inflated due to flex of the contact patch and sidewalls and the bike will wallow like a pissed hippo, so stick fairly close to the manufacturers recommended pressures ( they don't just pull them out of their arse) and remember those are cold pressures.
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« Reply #10 on: August 03, 2009, 12:16:59 AM »

 Roll Eyes Dragonworld is right on the money. check you (F) ride height, take 4 mm out perhaps, also if you went 'up' in front spring or 'up' in preload, both will slow the turning. What actually matters is the 'now' set up, so, check all the other variables, set them, then play "better/worse" start with the ride height. Aunty waytogo
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« Reply #11 on: August 03, 2009, 02:36:50 AM »

According to Gary J's "Advanced Suspension Setup Seminar" notes (something I found on some forum, maybe even this one) potential fixes for running wide in corners or slow turn in are:
-Increase shock spring preload (if sag incorrect).
-Increase rear ride height.
-Decrease fork spring preload (if sag incorrect).
-Move fork tubes up in triple clamps (lower front).
-Increase shock low speed compression damping.
-Decrease front fork compression damping.

I can't vouch for the credentials of Gary J but I (a rank novice in the suspension department) have found these notes useful when trying to nut out where to go with suspension adjustments.
If you're interested PM me and I'll see if I can forward them on to you.
Cheers.
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« Reply #12 on: August 03, 2009, 12:44:19 PM »

A common thing that I've seen a lot of riders do which causes them to understeer (Particularly when riding a sequence of corners) is to adjust the rebound damping on the rear waaay too much. Shocked

This causes the rear to "pack down" and stay down which in turn unloads the front end causing understeer.

Just a thought. It apparently comes from the "Just tighten everything up" school of suspension tuning,  laughingdp Roll Eyes
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« Reply #13 on: August 03, 2009, 01:14:20 PM »

With a harder spring on the front, as the spring compresses less when you're leaned over the bike will have a slower steering response. Any chages to spring rates will have a big effect on steering geometry under load.


A common thing that I've seen a lot of riders do which causes them to understeer (Particularly when riding a sequence of corners) is to adjust the rebound damping on the rear waaay too much. Shocked

This causes the rear to "pack down" and stay down which in turn unloads the front end causing understeer.



I believe that those two quotes nail the two most likely problems, probably working together.  In addition, if the front end is being kept high, you'll have less weight transfer to the front and thus less traction up their to set and control the cornering line.    You might experiment with an exaggerated forward shift of your body position for a few corners and see if the running wide problem is addressed.  If it is, you can be pretty sure that those quotes are describing the problems.

Tommy T.
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« Reply #14 on: August 03, 2009, 01:48:59 PM »

As for:
"Higher pressure = lesser contact patch = less friction = less grip = less wear"
how does a tyre slipping on the road due to less grip mean less wear?
Don't make sense.

Lucky I didn't mention slipping then ... only that it was a gross simplification and I don't know what I am talking about  Grin

But now I am a little confused, how does less grip not equal less wear?

With a harder spring on the front, as the spring compresses less when you're leaned over the bike will have a slower steering response. Any chages to spring rates will have a big effect on steering geometry under load.

This seems like a simple explanation waytogo - 'fixing' the suspension has changed the bike's geometry ... doesn't necessarily mean that it is set up wrong just that it is different to before and perhaps riding style or expectations need to change accordingly.
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