South Auckland Street Skills

[Sis]

John on the ST?

Yes, that John.
I hope you remembered your manners

Hope to see you next week.

[xXGIBBOXx]

Hope you all had a fun night , yeah I'm keen on a coffee run . Weekends seem the only time off for me ( well a few hours of which anyway ) hoping for me for next week to come out and play

[bawked]

Hope you had a chance to check us out.

Yep.. sure did, was good to meet some of the auckland biker folk and ride some new roads.

[eldog]

nzspokes - thanks for the info on syspension. worth investigating when I upgrade later for me
tigerdee - did it make a difference? I didnt hear. Try not to ride on the metal chip piles, you got me a few times its all good practise aye

keen to try coffee run. triple shot for me... $7 usually=f2dz

longer rides would be ok too. - need some practice after tuesday . Although ride home was perfect thanks john for listening

good to meet some new people.

I need to check the condition of the clutch. (so I can make sure it lasts on a longer run) manual says to stop engine for 5 mins every hour of travel.
couldnt see anything in the manual - maybe I missed a page.

[eldog]

do you get the blue words, popup small windows and other internet explorer windows opening by themselves when on KB site?
just wondering....

[nzspokes]

nzspokes - thanks for the info on syspension. worth investigating when I upgrade later for me
tigerdee - did it make a difference? I didnt hear. Try not to ride on the metal chip piles, you got me a few times its all good practise aye

keen to try coffee run. triple shot for me... $7 usually=f2dz

longer rides would be ok too. - need some practice after tuesday . Although ride home was perfect thanks john for listening

good to meet some new people.

I need to check the condition of the clutch. (so I can make sure it lasts on a longer run) manual says to stop engine for 5 mins every hour of travel.
couldnt see anything in the manual - maybe I missed a page.

Dont worry about the clutch. Just ride it.

Did you have a problem on Tuesday?

[eldog]

did I have a problem felt like peeling off and riding home even when we got to the cross roads at the end of runciman rd.
rode like a hairy goat all the rest of the way. tried to improve style as was suggested during my assessment. (no problems trying things or suggesstions)

I understand what was suggested, but need to do a lot more work to make happen for me. you and sis look easy and relaxed. - it will take time i know.

I ended up taking what I thought was all the wrong lines, and going way passed my comfort zone, the scorpio pulling me out just in time.

after our coffee stop, rode home like a champion I guess its a state of mind, confidence and comfort zone (bike and me)


clutch - burning smell during some parts of the ride - like clutch pad, cant be the brakes barely used them

talk tuesday!

[nzspokes]

did I have a problem felt like peeling off and riding home even when we got to the cross roads at the end of runciman rd.
rode like a hairy goat all the rest of the way. tried to improve style as was suggested during my assessment. (no problems trying things or suggesstions)

I understand what was suggested, but need to do a lot more work to make happen for me. you and sis look easy and relaxed. - it will take time i know.

I ended up taking what I thought was all the wrong lines, and going way passed my comfort zone, the scorpio pulling me out just in time.

after our coffee stop, rode home like a champion I guess its a state of mind, confidence and comfort zone (bike and me)


clutch - burning smell during some parts of the ride - like clutch pad, cant be the brakes barely used them

talk tuesday!

You will have rides where it just doesnt seem to come together. Good part is you know how it feels and you work to improve on it. Not try and be Rossi. Night riding is a new skill to be learned.

On a motorbike you get smells that you are not used to, like water burning off your headers which smell like your clutch. Or a car went though a few mins before with a stuffed clutch. Your bike is way to young to have an issue like that.

[eldog]

ok

[Tigadee]

tigerdee - did it make a difference? I didnt hear.

Yesh, it did! (Thanks Spokes, BTW)

Front doesn't feel soft any more and doesn't dip badly like it did before. Helps inspire more confidence heading into corners now...

Try not to ride on the metal chip piles, you got me a few times. its all good practise aye

Oh, sorry mate! Yeah, I realised I did go a bit wide sometimes in the corners and came close to the edges of the roads.

Good thing you've got some quality gear on!

Also some of those roads did have quite a bit of sand or gravel, especially at corners! Scary when it's dark!

did I have a problem felt like peeling off and riding home even when we got to the cross roads at the end of runciman rd.
rode like a hairy goat all the rest of the way. tried to improve style as was suggested during my assessment. (no problems trying things or suggesstions)

I understand what was suggested, but need to do a lot more work to make happen for me. you and sis look easy and relaxed. - it will take time i know. I ended up taking what I thought was all the wrong lines, and going way passed my comfort zone, the scorpio pulling me out just in time.

Don't sweat it... Can be a bit tough on a light little bike with a little tank but you'll get there. Maybe an excuse to look at a bigger LAMs bike?

Easier when it's still daylight and on familiar routes. We should take the Maraetai route next week...

And some counter-steering exercises in the car park. I suggested to Sis that we could re-introduce the one-handed steering. I realised on Tuesday that it will actually teach a lot about counter-steering (illustrating more vividly the pushing and pulling on handlebar during counter-steering).

This is also a good video:

[eldog]

Yesh, it did! (Thanks Spokes, BTW) - cool

metal was in the centre of the lane, you seemed to ride right into it at times, just be careful out there

the large amount of chip seal carried out lately hasnt been swept properly and the council should check and sweep all (esp rural) corners on a regualar basis, maybe the ACC should look at this, as could cause an accident.

I think this should be investigated further

[Tigadee]

metal was in the centre of the lane, you seemed to ride right into it at times, just be careful out there

Oh, I see! OK, thanks for the heads up!

Quite like how this video explains counter-steering:

[bawked]

Was good to learn a little about motorbike set-up, seeing as my background is in vehicle dynamics. The terminology was a bit.... off though.

Increasing pre-load doesn't increase the spring rate it increases the baseline force needed to start compressing the spring.... the rate at which it compresses after that does not change with the preload. Fs = Fp + Ks*X is the relevant eqn. So the ride rate isn't changed... and given that the rider weight variation has a much more substantial effect on ride rates on a bike (rider weight ~30-40%) as opposed to a car (where the driver weight is < 10%) the spring rates can easily be wrong and only changing them will fix the issue... changing the preload will not.

The below image shows what I mean.... the slope of the displacement/force is constant once the preload force has been overcome and is not affected by the preload amount. You could dial in a ridiculous amount of preload such that your suspension wouldnt move when you get on the bike, but wouldn't track the road very well as it will have no jounce travel.



Now damping.... hard/soft vs fast/slow. Why do we need damping!?! Well without damping a sprung system (your motorbike) would bounce down the road, because there is no force opposing the motion.... this is an unstable system. Meaning that the wheel is not under control, we add damping so that the oscillation dies so that the wheel will be ready for the next corner/bump.

We characterise the damping by a zeta value.... with 1 meaning that the system will oscillate once, less meaning some overshoot (bounce back as we saw) and higher meaning it'll take a longer time to return to the initial position. I don't know with regards to bikes what zeta values are ideal, but with race cars... somewhere in the order of 0.7 gives fast response times whilst not allowing excessive overshoot.

The image below illustrates the effect of the damping ratio on the response of the a sprung dampened system.



The frequency of the response to input or ride rate is determined by the spring rates, bike geometry (which determines the wheel rates.... which are the things that actually matter) and the damping (your bike has 4 different damping rates btw)

Ok bawked that's all good and well but how do dampers stop a system from osciallating? answer: by opposing motion... and the amount it opposes motion is dependant on only direction and velocity. So if your wheel ain't moving, a damper ain't doing a thing... whilst a spring probably is!

This is getting rather long for my liking so i'll end it there.... I've barely touched the surface and I tried not to get to technical but probably failed. I just want to get the right terminology out there...

* I haven't really looked into motorbike suspension, but I have done suspension design at uni

[xXGIBBOXx]

metal was in the centre of the lane, you seemed to ride right into it at times, just be careful out there

some times you just have to ride it out . there is a good bit on this in twist of the wrist on riding through wet lines , stones etc .

[nzspokes]

Was good to learn a little about motorbike set-up, seeing as my background is in vehicle dynamics. The terminology was a bit.... off though.

Increasing pre-load doesn't increase the spring rate it increases the baseline force needed to start compressing the spring

I keep it simple for a brief 15 min basic setup. And use terms most understand. Get to tech on suspension and people turn off.

You will see above Brian had an improvement from 2 bars of preload and half a turn off of rebound. And you would have seen from the static and rider sag settings his springs are way out of range for his weight. But we made the bike ride and handle better by simply turning his adjusters which also makes the bike safer. Ideally I would set his bike up with a .95 fork springs and a 1000lb rear, run 10w oil in the fork with a 125mm air gap.