I have noticed lately my bike wants to run wide on corners at higher speeds :o
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] (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 [clap]
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 .
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.
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.
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. ???
Are you going to fast ???
Are you backing of the throttle at any time through the bend ???
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 ???
using slight rear brake will pull the bike tighter into the turn.
Are you target fixating ???
I think we all know what happens here.
Have you chosen the wrong line ???
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 .
[thumbsup]
There is a link on the the oz-monster site with some more information. [thumbsup]
http://ozmonster.org/index.php?view=items&cid=1%3Amotorcycle&id=5%3Ariding-safe-techniques&option=com_quickfaq&Itemid=24 (http://ozmonster.org/index.php?view=items&cid=1%3Amotorcycle&id=5%3Ariding-safe-techniques&option=com_quickfaq&Itemid=24)
First things first.............
Did you redo the static ride height once everything was back together?? ???
Just chucking stuff back in just wont work. :o
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., ;D
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. [thumbsup]
Quote from: Dockstrada on August 02, 2009, 02:57:48 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. ???
Are you going to fast ???
Are you backing of the throttle at any time through the bend ???
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 ???
using slight rear brake will pull the bike tighter into the turn.
Are you target fixating ???
I think we all know what happens here.
Have you chosen the wrong line ???
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 .
[thumbsup]
There is a link on the the oz-monster site with some more information. [thumbsup]
http://ozmonster.org/index.php?view=items&cid=1%3Amotorcycle&id=5%3Ariding-safe-techniques&option=com_quickfaq&Itemid=24 (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
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 [laugh]
Agree that confidence in everything (the right combination) is a key contributing factor ... and also why I am so slow ;D
Dez I might be out for a little blat this Saturday will drop you a line later in the week to let you know.
Quote from: mattyvas on August 02, 2009, 08:13:28 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.
Sweeeeeeeet [clap] weather looks good for Sat and keen for a look at the new hot mix on the Old road
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.
[roll] 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 [thumbsup]
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.
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. :o
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, [laugh] [roll]
Quote from: brimo on August 03, 2009, 01:16:19 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.
Quote from: dragonworld on August 03, 2009, 01:44:19 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. :o
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.
Quote from: brimo on August 03, 2009, 01:16:19 AM
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 ;D
But now I am a little confused, how does less grip not equal less wear?
Quote from: brimo on August 03, 2009, 01:16:19 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.
This seems like a simple explanation [thumbsup] - '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.
Quote from: Betty on August 03, 2009, 02:48:59 PM
But now I am a little confused, how does less grip not equal less wear?
Less grip = more slippage
When you have slippage, you are removing bits of tyre ( hence the black marks on the asphalt)
like sandpaper on timber if you let it slip it removes bits of timber if you don't move it your timber stays the same.
Apologies if that sounds a bit patronising, just trying to paint a picture with words.
The centre of the tyre will wear more as that small contact patch has to deal with the forces of acceleration and decelleration.
You'll notice this particularly on car tyres that are overinflated, they'll tend to wear in the centre whereas underinflated (which is more common) will tend to wear the outside of the tread.
Yep, I see what you are saying - and I kinda figured that was what you meant.
But nobody has mentioned a lack of grip / lack of traction / slipping - I was simply responding to the advice of 'more pressure = less wear'.
I think its all semantics 8)
Update:
Thanks for the input guys, apparently a couple of things had been contributing to my problem
1. Tryre's ,replaced the squared off Battleaxes with some nice fresh PP's = helped
2. Mattys observation on apex timing=helped some more
3. Yesterday I dropped the the crown down the forks , after updating the forks I had never been happy as the bike felt too tall in the front and slow to turn in = big result the bike now feels balanced in the corner and a lot more flickable , the tyres have also quickened up the steering resulting in a happy bike and for me a return of confidence.
That's great Dez
Just remember not to do too many things at once as changing one small thing
might be just enough for you to notice the difference.
Changing too many things at the same time can confuse and cause further problems.
Does sound like you have it sorted though [thumbsup]
Many times I have seen people willing to shell out big bucks on a "you beaut" Ohlins shockie or a White Power front end and totally bypass those dirty, grotty black most often overlooked lumps of rose bush surround. [roll]
Doesnt matter how good or exotic your suspension is if the bit that touches the ground is "ratshit". ;D
Remember the KISS principle (Keep It Simple Stupid) and you'll more than likely save yerself some money, heartache and grief. [thumbsup]
Exactly.
I started a suspension tuning session with Teknik on the previous track day.
After some small tweaks and a small operation to change a plastic ring on the rear shock.
Bike feels great.
So again happy you have fixed your issues Dez, hope to see you out with us again soon.
I agree with everything already said.
But I must add, running wide in corners usually means your are going to fast. That is for either the bike or rider. Its all about gravity.
Cheers [beer]
Probably running wide in corners wasn't the best description of what was happening it was more like a feeling of understeer , I went for a quick blat today up mcars creek road and the effect of dropping the front has dramatically removed the feeling.
Even doing S turns on a straight (like a tyre warming exorcise) feels sharper and smoother.
Thanks again for the input.
Now when is the next group ride ;D
26th Sept Dez.
Come out if you can.