suspension help

Author
Discussion

mckeann

2,986 posts

230 months

Wednesday 22nd April 2015
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Prof Prolapse said:
It's actually no different from sitting in your car, having someone jack it up, then being curious why your head isn't closer to the roof.
FINALLY. We now have proof of the reason why alex can't understand this.

Prof Prolapse

16,160 posts

191 months

Wednesday 22nd April 2015
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Are you blaming me? confused

moanthebairns

Original Poster:

17,946 posts

199 months

Friday 24th April 2015
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All setup now within range.

Few things that might have fked me around the first time.

I must have wheeled it back on to the sslight slope in my garage making me thing it was adjusting the height.

Cold tyres.

Let me explain. I left my pressures in from Anglesey it was 18 degrees and I never checked them I'm the morning. Forgot. IBe taken my warmers off then went and got nose tested then when out with them cold. I've done three sighting laps which is normally enough to get them up to temperature but then someone crashed and when we went back out only got two Laps so not up to temp again

I came in thinking ice ruined it with the suspension changed it straight away then again out.

Also the seat was rather loose and the mount

It must Loosen in transport.

So I'll see how I get on at donnie.


mckeann

2,986 posts

230 months

Friday 24th April 2015
quotequote all
Prof Prolapse said:
Are you blaming me? confused
No. I was trying to rip the piss out of alex. I obviously failed.

moanthebairns

Original Poster:

17,946 posts

199 months

Tuesday 28th April 2015
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Bass come here and let me give you a huge kiss

I love you so much. You have fixed my bike. I cannot believe how good it feels. I love you for ever and Ever.

Before it was knee down once in a blue moon and fighting it.

Now it's knee down all the time no hassle laughing and giggling in the helmet

I love you lots bass

Tim85

1,742 posts

136 months

Tuesday 28th April 2015
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So what did you do since croft? What was the outcome?

Enjoy Craner curves. donnington is awesome!

moanthebairns

Original Poster:

17,946 posts

199 months

Tuesday 28th April 2015
quotequote all
Moved from just about one inch of sag to 30

It's like a new bike. It's so easy to ride now

sc0tt

18,054 posts

202 months

Tuesday 28th April 2015
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moanthebairns said:
Moved from just about one inch of sag to 30

It's like a new bike. It's so easy to ride now
30 inches of sag?

Tim85

1,742 posts

136 months

Tuesday 28th April 2015
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Ha.
I'm guessing 30mm

So you changed the sag 5mm...You sure it wasn't just you having a bad couple of days wink
Whatever it was as long as your enjoying it again that's the main thing. I'm having a right day getting my elbows down on the desk at work...

moanthebairns

Original Poster:

17,946 posts

199 months

Tuesday 28th April 2015
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Its night and day. Put it this way knee down was a chore before. I only got it a few times a track day.

Now it's nearly every corner without even trying no weight on the bars it just tips in I'm so relaxed with it now the bike feels like I'm riding it not it riding me

I cannot thank the advice enough

Prof Prolapse

16,160 posts

191 months

Tuesday 28th April 2015
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mckeann said:
Prof Prolapse said:
Are you blaming me? confused
No. I was trying to rip the piss out of alex. I obviously failed.
No it was me being a moron. Apologies.


CarsOrBikes

1,137 posts

185 months

Wednesday 29th April 2015
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Interesting read from the beginning

It sounds so much like you were measuring from the seat to the floor all the time, instead of the swing arm by the wheel nut, to the seat frame. Then it sounded like you were comparing settings with the feel of your feet on the floor when describing the crouched feel, instead of on the pegs, which don't and can't move independently of the seat subframe, or bike mainframe.

The percentage value of total travel is a good guide. The bike's own sag really could be measured too, and if doing this first, then seeing what the rider sag is (you in your normal riding gear sat on it), and if finding less than desired after taking the 1st measures, the springs maybe are too stiff, if greater than desired they are possibly too soft. It isn't something everyone bothers with, but is the starting point for the bikes weight, before yours. Everyone has different ways I suspect.

So, if the weight of the bike on it's own gives rear sag of 0-5mm measured from the vertical, axle bolt to subframe with the bike lifted (only ever measure to frame mounted metal parts), then with you on it looking for 25mm rider sag, I would say it's good on my own bike. Same with the front, where the bikes weight alone may give 25mm, measured between a cable tie on the fork leg to the tip of the seal with the bike lifted, and 35-40mm with you on it in gear, if ok great, otherwise as the above regarding too stiff or soft, give or take a small amount.

Then you might sit on the bike in your normal riding position and see if the rate of compression is the same as you sit down, so the front and rear of the bike compress at the same time, which is the initial balance. If this is out it can be managed by initial compression settings to the end which moves first, or even ride height adjustment sometimes.

Rebound is harder to check, but essentially, if the bike returns upward, then settles down again, when pushing quickly and firmly directly downward on it with no gear engaged or brakes applied, then add a small amount of rebound until the returning action is braked to an easy return only. All need rechecking if ride height is changed really. The front rebound is harder to check than rear, but a tip might be to either look at a fixed point in front of you, where you can still see the front of the bike in peripheral vision, rather than looking at the bike, with foreground in view, sounds silly perhaps, but aids checking it, or actually, test it when next to a clean car and use the reflection of the forks to see if they drop down again after returning.

Glad you feel it is sorted or improved. The suspension guys are good value from what most say, but as you identified, they all differ in opinion, and each track can mean different requirements for individuals anyway, so it is best to be familiar with these initial settings yourself in my opinion, and consult the guys on track for advice for that location, and keep notes of the settings for the weather and location, tyres etc.

You earlier mentioned pushing or pulling on the bar, unsure which, but it is pushing the inside bar that you most likely do naturally. I don't imagine I would want to pull the outer bar on a committed turn. You can assist the turn by weighting the inside peg, although it feels odd, but works.

You mentioned the rear shock linkage, and this can bind causing all sorts of hassle, so at ten years old it is worth complete removal for cleaning and checking. Someone also mentioned headstock bearings, so worth a check.

Anyway, only my2p after you fixed it haha

moanthebairns

Original Poster:

17,946 posts

199 months

Wednesday 29th April 2015
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I went I'm search of easy answers I started questioning my riding due to the suspension expert saying it was spot on.

I just thought I was st,I mean I still am but I'm much more happy now.

I realise now the suspension guy couldn't be arsed setting my sag. It's not a two minute job.

Still it's done. It's getting left and I'm happy. I can't thank others enough. It's night and day.

upsidedownmark

2,120 posts

136 months

Tuesday 19th May 2015
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Thread resurrection!

So, me, plus ducati 848. Big change from the previous ER6 which I tracked a few times, despite fairings the ER6 is quite upright and has wide bars. I felt that I knew what it was doing / had 'feel' and some confidence tipping in. Enter the duke. 90% of the time I have no idea what it's doing, and feel like I'm trying to wrestle it around. Occasionally it feels brilliant, but only when I attack a corner, and certainly I need to be moving around the seat a bit - I suspect starting to move my weight inside also helps me to push the bars around. Have taken this to be largely a 'me' issue, plus ducati not wanting to be ridden at 50%, plus generally sportsbike. (I'm a complete wuss on the road)

Had it out on track. Not ideal, P****ed down. Also got suspension looked at:

Initial figures (mm):

Front Rear
Static 20 5
Rider 40 35
Drop?? 80


Preload rear - not measured or adjusted
Preload front - was 5/7 (rings showing), changed to 6/7 showing.

Front compression and rebound reduced (very slightly), rear compression increased very slightly / rebound halved.

Hard to tell much on a soaking track when you keep scaring yourself silly with wheelspin; felt a little more confident on exit, *seemed* to be a little less snappy. Rebound still looks quite slow from the back, certainly no bounce - I thought they'd put more on, but the sheet says they took some off.

Subjective feel is quite stiff at the back, squidgy at the front. Somewhat bothered they reduced the front preload, looking at that I'd have thought more. If I understand these things correctly, the spring is significantly longer than the suspension travel, we don't worry about it going coil bound, so adding preload moves us along the force/compression slope to the right - we start moving at a higher force, and have more push back when we get to the bump stop, despite that rising at the same number of kg/mm etc?

The ziptie looks a long long way towards the bottom of the fork to me (thinking bumpstop?) especially as it was soaking and I really wasn't killing it on the brakes.



Any thoughts / suggestions welcome (especially from the resident suspension guru..)

Edited by upsidedownmark on Tuesday 19th May 18:10

sc0tt

18,054 posts

202 months

Tuesday 19th May 2015
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I dread having to do any suspension work on my bike

bass gt3

10,205 posts

234 months

Tuesday 19th May 2015
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upsidedownmark said:
Thread resurrection!

So, me, plus ducati 848. Big change from the previous ER6 which I tracked a few times, despite fairings the ER6 is quite upright and has wide bars. I felt that I knew what it was doing / had 'feel' and some confidence tipping in. Enter the duke. 90% of the time I have no idea what it's doing, and feel like I'm trying to wrestle it around. Occasionally it feels brilliant, but only when I attack a corner, and certainly I need to be moving around the seat a bit - I suspect starting to move my weight inside also helps me to push the bars around. Have taken this to be largely a 'me' issue, plus ducati not wanting to be ridden at 50%, plus generally sportsbike. (I'm a complete wuss on the road)
Bear in mind Ducatis are notoriously slow on initial turn in. Avoid excessive lowering of the front or raising the rear to speedup the steering, it causes worse problems for very little gain.
Rather get used to it and initiate the turns with a little more force. The upside is they're very stable mid corner.

upsidedownmark said:
Had it out on track. Not ideal, P****ed down. Also got suspension looked at:

Initial figures (mm):

Front Rear
Static 20 5
Rider 40 35
Drop?? 80


Preload rear - not measured or adjusted
Preload front - was 5/7 (rings showing), changed to 6/7 showing.
Figures seems ok but you don't mention your weight in your gear.
Rear preload is easy to measure. Just look at the rear shock and measure how many threads are showing above the top of the top ring. Typically it should be around 12mm. Also, if it's the Ohlins shock, what's the code number on the spring?
Regarding front preload, ignore how many rings are showing. Calculate in number of turns from fully out. Typically you should have around 10 to 12 turns available, and 1 turn of the adjuster equates to about 1mm of preload.

upsidedownmark said:
Front compression and rebound reduced (very slightly), rear compression increased very slightly / rebound halved.

Hard to tell much on a soaking track when you keep scaring yourself silly with wheelspin; felt a little more confident on exit, *seemed* to be a little less snappy. Rebound still looks quite slow from the back, certainly no bounce - I thought they'd put more on, but the sheet says they took some off.
Again, how many clicks from fully closed are we talking about?
Remember that you can only assess the suspension once it's warmed up. If it's stone cold, it will seem a lot slower than when it is warmed up.
As for being on a wet track, it's hardly the best place to be figuring out your suspension. It also depends on what tyres you were on..

upsidedownmark said:
Subjective feel is quite stiff at the back, squidgy at the front. Somewhat bothered they reduced the front preload, looking at that I'd have thought more. If I understand these things correctly, the spring is significantly longer than the suspension travel, we don't worry about it going coil bound, so adding preload moves us along the force/compression slope to the right - we start moving at a higher force, and have more push back when we get to the bump stop, despite that rising at the same number of kg/mm etc?
Preload really only adjusts ride height. Yes, it puts more force into the spring but if you measure it all, you'll see the fork extends in line with the preload you add. So wind in 3 turns of preload and you'll find the fork stanchion is now 3mm longer.
The ideal is to have your preload in the middle zone. If the springs are right for your weight, that'll give you a few mm each way to fine tune.
Remember... Preload DOES NOT change spring rate!

upsidedownmark said:
The ziptie looks a long long way towards the bottom of the fork to me (thinking bumpstop?) especially as it was soaking and I really wasn't killing it on the brakes.



Any thoughts / suggestions welcome (especially from the resident suspension guru..)


It's fine to have the tell tale about 10mm from the bottom. Depending on bump stop and air gap but 10mm is a good target. Even if you were standing the bike on it's nose under braking, that doesn't mean you'll get it any lower.

As for setting up your suspension, really only you can decide what works for you. But you'd be amazed how close to factory settings you might end up wink

Mr OCD

6,388 posts

212 months

Tuesday 19th May 2015
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bass gt3 said:
As for setting up your suspension, really only you can decide what works for you. But you'd be amazed how close to factory settings you might end up wink
This ... After hours of 'experimenting' other than sag being setup I'm pretty much on standard comp and rebound settings for the road ... A tiny bit more compression for track is all it needs.

upsidedownmark

2,120 posts

136 months

Tuesday 19th May 2015
quotequote all
bass gt3 said:
Bear in mind Ducatis are notoriously slow on initial turn in. Avoid excessive lowering of the front or raising the rear to speedup the steering, it causes worse problems for very little gain.
Rather get used to it and initiate the turns with a little more force. The upside is they're very stable mid corner.
Ok, yup. More concerned that I have no clue for grip, but maybe just more seat time..

upsidedownmark said:
Initial figures (mm):

Front Rear
Static 20 5
Rider 40 35
Drop?? 80


Preload rear - not measured or adjusted
Preload front - was 5/7 (rings showing), changed to 6/7 showing.
bass gt3 said:
Figures seems ok but you don't mention your weight in your gear.
Rear preload is easy to measure. Just look at the rear shock and measure how many threads are showing above the top of the top ring. Typically it should be around 12mm. Also, if it's the Ohlins shock, what's the code number on the spring?
Regarding front preload, ignore how many rings are showing. Calculate in number of turns from fully out. Typically you should have around 10 to 12 turns available, and 1 turn of the adjuster equates to about 1mm of preload.
Me - 85kg in gear.

Not Ohlins sadly. 10-12mm I'd say (by eye) at rear, rider sag seems to be spot on with the sort of numbers you talk about way back in this thread. No idea about ride height - if I understand the funky multilinkage thing, then I can adjust that separately.. perhaps one thing too many.

I'll try to find a suitable sized spanner for the front, but meantime, 7 rings show fully out, none fully in, so we're a long way towards the 'out' side, nowhere near 1/2 way.

Given 40mm is on the high side of what you quoted, I was surprised they took preload off, which would leave me with more sag than currently (as I understand it).

bass gt3 said:
Again, how many clicks from fully closed are we talking about?
Remember that you can only assess the suspension once it's warmed up. If it's stone cold, it will seem a lot slower than when it is warmed up.
As for being on a wet track, it's hardly the best place to be figuring out your suspension. It also depends on what tyres you were on..
OK:

range before after
Front compression 3 turns 3/4 from out 1/2
Front rebound 16 clicks 8 6
Rear compression 4 1/2 turns 2 2 1/2
Rear rebound 16 clicks 12 6


Tyres - pirelli diablo rosso (sportyish, but reasonably long lifed road tyre)

bass gt3 said:
Preload really only adjusts ride height. Yes, it puts more force into the spring but if you measure it all, you'll see the fork extends in line with the preload you add. So wind in 3 turns of preload and you'll find the fork stanchion is now 3mm longer.
The ideal is to have your preload in the middle zone. If the springs are right for your weight, that'll give you a few mm each way to fine tune.
Remember... Preload DOES NOT change spring rate!
Absolutely understand RATE (so long as it's a linear rate spring wink )

For some reason from my car days I had an idea that it wasn't going to rise

lets say my hypothetical spring is 1kg/cm and isn't topped out or bottoming. The suspension travel is 10cm, but the spring has 15cm of travel. Without preload we'll go from 0-10kg. When we preload it, we shorten the spring by (say) 2cm, (but the ride height isn't changed, so I guess we were moving something else to compensate on the car) - our working range is 2-12kg. Nothing moves until we get 2kg of load, then it behaves in the same old linear fashion as before.

So maybe a light going on that the bike is different - it's going to rise by 1cm at the front? So preload should make no difference to the sag at all? We never measured ride height, so what are we targeting with the preload?

bass gt3 said:
It's fine to have the tell tale about 10mm from the bottom. Depending on bump stop and air gap but 10mm is a good target. Even if you were standing the bike on it's nose under braking, that doesn't mean you'll get it any lower.

As for setting up your suspension, really only you can decide what works for you. But you'd be amazed how close to factory settings you might end up wink
OK - I was concerned that I might be sitting on the bump stop (or equivalent) which usually leads to skittish behaviour.. But then I'm transferring a (little) knowledge from being a greasy monkey for a (car) racing outfit many years ago.

Bought the bike secondhand, for all I know the previous owner screwed around with it, and I have no clue what the factory settings should be, or I'd start there. Main concern is to be in the ballpark so I know I'm not trying to ride around something fundamentally borked, then I'll just get on with riding it and probably never touch anything.

Thanks smile

bass gt3

10,205 posts

234 months

Tuesday 19th May 2015
quotequote all
So it's an 848 with Showa suspension?
Actually I prefer the Showa for road, it's far less harsh than the Ohlins (which isn't actually much good tbh)

So preload on a bike fork is slightly different to a car. On the bike, you'll have a top out spring, which works against the normal spring, with the stanchion in balance between the two spring forces.
So winding preloading pushes against the top out spring, compressing the main spring and effectively lengthening the fork, hence ride height is changed. This is important to remember. So whilst the preload can seem to be changing the sag, it isn't really. Sag is obviously dictated by the spring force, so you may wind in or out the preload to achieve a given target but you're also changing the ride height. Bit of a fudge really, but if your preload is in the midzone with the achieved sag being right, the springs are good. If not, look to change the springs. There is no substitute for having the correct springs, it transforms the bike.
The target is to get (for road) 40 to 50mm of dynamic sag in the front. So if you have a typical fully extended length of 125mm of stroke, about 1/3rd is the target to be taken by dynamic sag. Next up consider the air gap. It should be considered as an additional spring in function. The chart for oil height vs stroke resistance is pretty exponential as the air gap diminishes. Ohlins recommend a typical value of no more than 150mm for road and track use, and I'd even look at more than that for a primarily road bike. 170mm air gap is good.
As for compression and rebound damping, think of the rebound needing to be as fast as possible without a double bounce. This is usually achieved in the first 1/3rd of clicks towards fully open. Compression is subjective as you can use it to mitigate brake dive but balance that against bump compliance. Start at half way and see how it feels.
Try to allow the bike to have some suspension rather than being as stiff as a pole. It allows the tyres to maintain traction especially ona95% road bike.


Edited by bass gt3 on Tuesday 19th May 20:23

upsidedownmark

2,120 posts

136 months

Tuesday 19th May 2015
quotequote all
OK, thanks - going to try to digest that for a bit. Far as I'm aware its showa - 2009 base spec 848, no fancy ohlins decals or gold bits..

edit.. looks like it says showa on the casting at the bottom of the fork in the pic above, so I'm going to say yes, showa smile