SetUp - Race Reps versus Heavy Weight Bikes - ZRX1200
Discussion
I read with great interest discussion - Static v Rider Sag, quite a master class on suspension set up. Thought provoking but it related to Fireblade which has a vastly different geometry and just wondered what difference it makes to approach.
Bike came to me with rear shocks suited to 12 stone rider - I am 17 stone with full leathers etc. I managed to get bikes supension to rise and fall at the same rate front and back but very soft. Now have more suitable springs at rear and 0.97Kg/mm front springs.
Bike came to me with rear shocks suited to 12 stone rider - I am 17 stone with full leathers etc. I managed to get bikes supension to rise and fall at the same rate front and back but very soft. Now have more suitable springs at rear and 0.97Kg/mm front springs.
Thanks for getting back - that was my concern when I read the original topic that grabbed my attention "Static v Rider Sag. I take it that figure is available from spec sheet for that model - or can I measure it? Total length of fork suspended off the ground between dust seal and lower triple tree 155mm.
2001 specs - Suspension travel front 120mm, rear 123mm-that would make rider sag required around 40mm front and back.
Last measured rider sag with summer weight textile gear on:
Front: 34mm
Rear: 33mm
Leathers alone approx 20 1bs so will have some effect - need to get fully togged up before tweaking in.
2001 specs - Suspension travel front 120mm, rear 123mm-that would make rider sag required around 40mm front and back.
Last measured rider sag with summer weight textile gear on:
Front: 34mm
Rear: 33mm
Leathers alone approx 20 1bs so will have some effect - need to get fully togged up before tweaking in.
Edited by oldninjaron on Wednesday 26th August 22:13
Often the manufacturer will provide the suspension stroke numbers.
On road bikes the total amount of fork slider showing with the bike lifted can be misleading as there might be bump stops installed etc.
So if you use the manufacturers specs, aim for 1/3rd to be rider sag.
Remember that you can also use the compression adjustment (if fitted) to slow the initial reaction of the suspension such as under braking.
But if you've got 120mm ish of total stroke I'd be happy at 35 to 45mm rider sag.
You can also play with oil weights and air gap to tune the suspension beyond the basic spring values. Also, I think (might be wrong) that Kawasaki were very fond of using progressive springs in their bikes so they might feel softish at the top of the stroke but get significantly stiffer through the stroke.
On road bikes the total amount of fork slider showing with the bike lifted can be misleading as there might be bump stops installed etc.
So if you use the manufacturers specs, aim for 1/3rd to be rider sag.
Remember that you can also use the compression adjustment (if fitted) to slow the initial reaction of the suspension such as under braking.
But if you've got 120mm ish of total stroke I'd be happy at 35 to 45mm rider sag.
You can also play with oil weights and air gap to tune the suspension beyond the basic spring values. Also, I think (might be wrong) that Kawasaki were very fond of using progressive springs in their bikes so they might feel softish at the top of the stroke but get significantly stiffer through the stroke.
Edited by bass gt3 on Wednesday 26th August 22:22
ZRX 1200 Kawasaki has Maxton revalved forks with 0.97Kg/mm springs fitted to standard forks - compression/rebound damping/preload adjustment available. Rear shocks OHLINS with same adjustments available.
If I am lucky with full leathers on could get pretty close to necessary sag - at worst small adjustment only required.
As per previous topic I have set front and back rebound damping to 1/3 approx only of that available. When soft springs fitted on rear shocks found it very easy with 10 out of 18 clicks compression out, on forks, to balance front and rear. When cold suspension when compressed by hand both front and rear suspension rose at same rate - felt the same on the road over gentle undulations without bottoming - sag then front and back approx 35mm.
Since then heavier springs on rear shocks. Once sag tweaked in, would the same method of tweaking in compression front and rear, albeit v soft to start with, to get the same balance be a good place to go next?
If I am lucky with full leathers on could get pretty close to necessary sag - at worst small adjustment only required.
As per previous topic I have set front and back rebound damping to 1/3 approx only of that available. When soft springs fitted on rear shocks found it very easy with 10 out of 18 clicks compression out, on forks, to balance front and rear. When cold suspension when compressed by hand both front and rear suspension rose at same rate - felt the same on the road over gentle undulations without bottoming - sag then front and back approx 35mm.
Since then heavier springs on rear shocks. Once sag tweaked in, would the same method of tweaking in compression front and rear, albeit v soft to start with, to get the same balance be a good place to go next?
Edited by oldninjaron on Wednesday 26th August 22:37
Edited by oldninjaron on Wednesday 26th August 22:38
oldninjaron said:
If I am lucky with full leathers on could get pretty close to necessary sag - at worst small adjustment only required.
As per previous topic I have set front and back rebound damping to 1/3 approx only of that available. When soft springs fitted on rear shocks found it very easy with 10 out of 18 clicks compression out to balance front and rear. When cold suspension when compressed by hand both front and rear suspension rose at same rate - felt the same on the road over gentle undulations without bottoming - sag then front and back approx 35mm.
Since then heavier springs on rear shocks. Once sag tweaked in, would the same method of tweaking in compression front and rear to get the same balance be a good place to go next?
Don't get too hung up on absolute numbers. It's the overall suspension feel you're looking for. Heavier springs at the rear might not make much overall difference as said, there are possibly progressive springs in the front. So their rate increases with load so initially the front might feel softer than the rear but then getting stiffer.As per previous topic I have set front and back rebound damping to 1/3 approx only of that available. When soft springs fitted on rear shocks found it very easy with 10 out of 18 clicks compression out to balance front and rear. When cold suspension when compressed by hand both front and rear suspension rose at same rate - felt the same on the road over gentle undulations without bottoming - sag then front and back approx 35mm.
Since then heavier springs on rear shocks. Once sag tweaked in, would the same method of tweaking in compression front and rear to get the same balance be a good place to go next?
Pop a cable tie on a fork slider and a rear shock rod and see what kind of stroke you're using in general riding.
But go by feel, it's a very personal thing
So use the guidelines to get it in the ballpark and then ride and adjust as necessary.
My ZRX 1200 Kawasaki has Maxton revalved forks with 0.97Kg/mm linear springs fitted to standard forks - compression/rebound damping/preload adjustment available. Rear shocks OHLINS with same adjustments available.
Ever since I watched the electric bikes racing at TT, pretty heavy machines, watching their suspension rise and fall in unison over the bumps I have been determined to learn about suspension and how it can be tuned in. It felt good feeling my bike doing the same over those long undulations, on soft springs - which meant a good place to start once ride height close to ideal at least balanced.
It is very true it is a very interesting subject.
I have fitted neoprene tubes covers on front forks which are nice and tight which allows witness to front fork action. Cable ties then on shocks. I presume then sit on bike before leaving drop the neoprene tubes onto dust seals and same for cable ties - measure up on return, makes sense.
Ever since I watched the electric bikes racing at TT, pretty heavy machines, watching their suspension rise and fall in unison over the bumps I have been determined to learn about suspension and how it can be tuned in. It felt good feeling my bike doing the same over those long undulations, on soft springs - which meant a good place to start once ride height close to ideal at least balanced.
It is very true it is a very interesting subject.
I have fitted neoprene tubes covers on front forks which are nice and tight which allows witness to front fork action. Cable ties then on shocks. I presume then sit on bike before leaving drop the neoprene tubes onto dust seals and same for cable ties - measure up on return, makes sense.
Edited by oldninjaron on Thursday 27th August 07:16
Managed to get out on the road today for approx 40 mins, in the rain unfortunately, so very gentle, pretty greasy out there.
Found a lot of front fork/handlebar "action" as if not coping not sure because soft or too much rebound or even both - felt every bump on even pretty much unbroken but bumpy roads compared to rear that occasionally boosted me out of seat a little.
Front suspension useage, witnessed by neoprene sleeves, appeared to be approx 37mm.
Rear suspension, oops placed cable tie at bottom rather than top to start therefore no data yet.
Hopefully weather will improve later - need to get out again.
Found a lot of front fork/handlebar "action" as if not coping not sure because soft or too much rebound or even both - felt every bump on even pretty much unbroken but bumpy roads compared to rear that occasionally boosted me out of seat a little.
Front suspension useage, witnessed by neoprene sleeves, appeared to be approx 37mm.
Rear suspension, oops placed cable tie at bottom rather than top to start therefore no data yet.
Hopefully weather will improve later - need to get out again.
Weather was good so out I went for approx 2 hours which involved repeat runs up and down the same road with measuring tape and flat bladed screw driver.
First run revealed some intriguing results: Front suspension useage 46mm, rear 56mm! If I read this correctly that is some imbalance.
Tweaked front compression damping first from 7 clicks out, of 18, to 9 out, of 18 which - result 49mm useage, rear same as before.
Tweaked rear compression damping from 8 clicks out, of 22, to 3 of 22 - result 51 mm useage.
Now that is more of a balance? It does disturb me just how much the rear shocks are moving though? Would it be fair to say that I need to increase the rear preload rear to cope with this perhaps reducing shock length, Ohlins, proportional to any ride height increase? Last measured as approx 35mm of rider sag front and back.
First run revealed some intriguing results: Front suspension useage 46mm, rear 56mm! If I read this correctly that is some imbalance.
Tweaked front compression damping first from 7 clicks out, of 18, to 9 out, of 18 which - result 49mm useage, rear same as before.
Tweaked rear compression damping from 8 clicks out, of 22, to 3 of 22 - result 51 mm useage.
Now that is more of a balance? It does disturb me just how much the rear shocks are moving though? Would it be fair to say that I need to increase the rear preload rear to cope with this perhaps reducing shock length, Ohlins, proportional to any ride height increase? Last measured as approx 35mm of rider sag front and back.
Edited by oldninjaron on Thursday 27th August 22:55
I have to admit to some confusion. I am not sure that Ohlins' option to adjust length of shocks and I have taken that option might be masking issues or upsetting my intention to adjust my rear suspension when it comes to adjusting rider sag etc.
Recent testing revealed that as much as 50mm of suspension useage,front and rear, whilst riding, when compared to bike alone impacting on suspension. This equates to nearly all that available at rear making it very easy to bottom the shocks???
Recent testing revealed that as much as 50mm of suspension useage,front and rear, whilst riding, when compared to bike alone impacting on suspension. This equates to nearly all that available at rear making it very easy to bottom the shocks???
It was time for a bit of lateral thinking - one question has always puzzled me, why when setting up suspension do we measure fork travel at front but measure differences in height, effectively, at rear, especially since, I suspect, all models are likely to be different, hence my original question?
I recall from a previous topic that the aim, initially, was to aim for rider sag of 1/3 total suspension travel - you can perhaps seen my confusion especially since we are to aim for equal rider sag front and rear.
Today I decided to measure rider sag in the usual manner - subtract fork travel and change in height at rear from measurements taken when forks/shocks fully extended plus also measured shock travel.
Remaining shiny bit on my shocks was a mere 11mm left above rubber stopper on previous testing during riding. Seemed too close to bottoming out.
Double checked all my measurements and upped the pre-load on rear with all damping to min, rear rider sag set to 36mm, front 30.
Took her out and with a few passes on same road, adjusted compression damping at front to match up front and rear suspension useage - 46 mm but more importantly especially at shocks left approx 25mm for the worst of roads to cope with and front end seems much more stable.
Still feeling some of sharp bumps but rebound damping still not touched, currently set front and rear to 1/3 of possible adjustment, from minimum.
I recall from a previous topic that the aim, initially, was to aim for rider sag of 1/3 total suspension travel - you can perhaps seen my confusion especially since we are to aim for equal rider sag front and rear.
Today I decided to measure rider sag in the usual manner - subtract fork travel and change in height at rear from measurements taken when forks/shocks fully extended plus also measured shock travel.
Remaining shiny bit on my shocks was a mere 11mm left above rubber stopper on previous testing during riding. Seemed too close to bottoming out.
Double checked all my measurements and upped the pre-load on rear with all damping to min, rear rider sag set to 36mm, front 30.
Took her out and with a few passes on same road, adjusted compression damping at front to match up front and rear suspension useage - 46 mm but more importantly especially at shocks left approx 25mm for the worst of roads to cope with and front end seems much more stable.
Still feeling some of sharp bumps but rebound damping still not touched, currently set front and rear to 1/3 of possible adjustment, from minimum.
Edited by oldninjaron on Saturday 29th August 17:54
Edited by oldninjaron on Sunday 30th August 08:35
oldninjaron said:
It was time for a bit of lateral thinking - one question has always puzzled me, why when setting up suspension do we measure fork travel at front but measure differences in height, effectively, at rear, especially since, I suspect, all models are likely to be different, hence my original question?
Because on a mono-shock rear end:1) It's usually quite difficult to measure the length of a shock itself
2) The rising rate linkage means that there isn't a 1:1 correlation between suspension travel and shock travel.
Since the entire purpose of sag is to set the average operating position of the suspension to provide adequate rebound travel, it makes no sense to measure the shock length in this case.
On a twin shock machine the shock length and rear end height are directly related, so you could measure shock length to set up sag.
Thanks for the confirmation - yes see what you mean real pain with monoshock plus you have the linkages to take into consideration - twin shock no linkages and much easier to eyeball, cheers.
Front and rear sag do not match at the mo but it feels much better - next step i guess would be to reduce preload on front and perhaps, if necessary another tweak of compression damping.
Front and rear sag do not match at the mo but it feels much better - next step i guess would be to reduce preload on front and perhaps, if necessary another tweak of compression damping.
Last runs felt very good, front end much more stable and at the time felt merely a matter of some rebound damping adjustment to finish off but .....next day stability gone during a warm up run but it did not get any better. Trouble is veered off at a tangent, lost my methodical approach so now back to square one.
Spoke to a gent at Kais re OHLINS shock etc. He thought KA416 shocks with 06390-05 springs (24-33Nm) should manage bike and my weight but that Rider sag should be something around 30mm - especially since shock stroke 91mm as opposed to Kawasaki OEM shock 123mm?) Had already proven that 30mm of a Rider sag was mecessary at rear to guarantee some spare to prevent bottoming out which had happened at approx 35mm.
Bike now at 30mm rider sag at front and rear, Rebound F:10 out of 15, R: 40 out of 60, Compression F: 12 out of 18, R: 14 out of 21, Preload F: 3 lines showing, R: 17 threads showing above adjuster ring. Just as an aside Static Sag F: 22mm, R: 11mm - an indication that front and rear springs within spec for bike alone.
Intermittent Scottish monsoon past couple of days so waiting to give bike some more test and adjust runs.
Spoke to a gent at Kais re OHLINS shock etc. He thought KA416 shocks with 06390-05 springs (24-33Nm) should manage bike and my weight but that Rider sag should be something around 30mm - especially since shock stroke 91mm as opposed to Kawasaki OEM shock 123mm?) Had already proven that 30mm of a Rider sag was mecessary at rear to guarantee some spare to prevent bottoming out which had happened at approx 35mm.
Bike now at 30mm rider sag at front and rear, Rebound F:10 out of 15, R: 40 out of 60, Compression F: 12 out of 18, R: 14 out of 21, Preload F: 3 lines showing, R: 17 threads showing above adjuster ring. Just as an aside Static Sag F: 22mm, R: 11mm - an indication that front and rear springs within spec for bike alone.
Intermittent Scottish monsoon past couple of days so waiting to give bike some more test and adjust runs.
Edited by oldninjaron on Wednesday 2nd September 08:32
Dodging rain today took her out after warm up run - feeling every bump especially through the bars, in particular short sharp bumps. Suspension useage, forks and shock struts approx 47mm after this run. Occasionally boosted out of rear seat - decided to try rebound damping route initially increased at forks by 3 clicks in - to no avail just as bad - reversed then 3 more clicks out again TNA. Tried same at rear same result.
Tried reducing compression damping on the last run at the front, now 14 out of 18 and rear by two clicks, now 18 out of 24 things seem to calm down at the front, much more comfortable - could be something in the right direction, finally.
Tried reducing compression damping on the last run at the front, now 14 out of 18 and rear by two clicks, now 18 out of 24 things seem to calm down at the front, much more comfortable - could be something in the right direction, finally.
Yet another red herring. Neoprene tubes on front forks not allowing correct monitoring fork useage - corrected to allow accurate measurement. After warm up of suspension measured shock rod useage found 45mm and 60mm fork useage - definitely not a balance despite rider sag of 30mm, front and back, this would suggest matching sag front and back not the way to go. Adjustments of damping confirmed only to adjust rates not amount. I had better check rider sag again!!!! If still correct - suspension useage figures would indicate that perhaps rear too high compared to front as weight would appear to be loading up front????? or.....?
Edited by oldninjaron on Friday 4th September 07:07
Time for an experimental approach to this - if nothing else just to test a theory that my test road may be too much for most suspension even my very soft Citroen.
It would appear my first aim is to achieve balanced suspension, front and rear in terms of useage. I do not have any linkage at rear, as twin shock set up, measurements as at front can be taken from shock rod as well as fork shiny bits.
Perhaps controversially, removed all damping front and rear, what a bouncy ride, initially with rider sag as above - initially fork useage measured as 65mm, shocks 45mm. After many runs bouncy castle style, bit like riding my old Kawasaki Z1000 Mk2 in the '80s without pillion, actually not half bad, after reducing shock preload in stages shock useage increased to 50mm, at this point unable to increase same, so increased preload by five "notches". Fork useage now 63mm, shock 50mm. It will be in the garage today to increase fork preload from 3 1/2 lines visible to 4 hopefully we should then get close to a match.
Actually felt very confident about ride with no damping, yes bouncy but not unpredictable and majority of bumps softened out and none of that short sharp nause through the bars .
It would appear my first aim is to achieve balanced suspension, front and rear in terms of useage. I do not have any linkage at rear, as twin shock set up, measurements as at front can be taken from shock rod as well as fork shiny bits.
Perhaps controversially, removed all damping front and rear, what a bouncy ride, initially with rider sag as above - initially fork useage measured as 65mm, shocks 45mm. After many runs bouncy castle style, bit like riding my old Kawasaki Z1000 Mk2 in the '80s without pillion, actually not half bad, after reducing shock preload in stages shock useage increased to 50mm, at this point unable to increase same, so increased preload by five "notches". Fork useage now 63mm, shock 50mm. It will be in the garage today to increase fork preload from 3 1/2 lines visible to 4 hopefully we should then get close to a match.
Actually felt very confident about ride with no damping, yes bouncy but not unpredictable and majority of bumps softened out and none of that short sharp nause through the bars .
Edited by oldninjaron on Sunday 6th September 08:57
Edited by oldninjaron on Sunday 6th September 20:06
The basics looked very straightforward re rider sag set up but that has not proved so - do not know if Ihave necessary springs fitted for bike and my weight. That said might just need a good service because apart from when damping completely removed where I can manually bounce bike checking for a balance, I get the feeling that there might be a reluctance for forks to respond perhaps issue there. Might upset measurements at least for the front end.
Feel like I have being going round in circles.
Feel like I have being going round in circles.
Rider sag, settled on the following for now:
Forks: F1 = 153, F3 = 108 with preload 8 turns in from fully out therefore Rider sag = 45mm.
Shocks: Using measurements based around strut length only - rear suspension does not have linkage etc.
R1 = 91, R3 = 61mm therefore strut sag = 30mm equates to approximately third of available, includes rubber stop.
After good long ride using cable ties on forks and shock with the following rebound and compression settings:
Forks: Rebound = 10 clicks out of 15. Compression = 12 clicks out of 18.
Shocks: Rebound = 40 clicks out of 60. Compression = 16 clicks out of 24.
Useage
Front: 72mm, Rear 53
Felt a lot more confident although not perfect although having ridden the same road so many times I know where all the bumps are - even with rider sag set with no damping at all just to see how it felt when in a very loose state - felt like going back 30 to 40 years to my Kwack Z1000 days. With settings above it felt more controlled plus riding over longer bumps felt like front and back rising and falling approximately together. Before leaving, not very scientific I know with suspension warmed up an earlier run, noticed even just standing up and sitting down repeatedly front and back seemed to lower and rise about the same amount and approx same rate.
Any comments please about results above would be very welcome?
Forks: F1 = 153, F3 = 108 with preload 8 turns in from fully out therefore Rider sag = 45mm.
Shocks: Using measurements based around strut length only - rear suspension does not have linkage etc.
R1 = 91, R3 = 61mm therefore strut sag = 30mm equates to approximately third of available, includes rubber stop.
After good long ride using cable ties on forks and shock with the following rebound and compression settings:
Forks: Rebound = 10 clicks out of 15. Compression = 12 clicks out of 18.
Shocks: Rebound = 40 clicks out of 60. Compression = 16 clicks out of 24.
Useage
Front: 72mm, Rear 53
Felt a lot more confident although not perfect although having ridden the same road so many times I know where all the bumps are - even with rider sag set with no damping at all just to see how it felt when in a very loose state - felt like going back 30 to 40 years to my Kwack Z1000 days. With settings above it felt more controlled plus riding over longer bumps felt like front and back rising and falling approximately together. Before leaving, not very scientific I know with suspension warmed up an earlier run, noticed even just standing up and sitting down repeatedly front and back seemed to lower and rise about the same amount and approx same rate.
Any comments please about results above would be very welcome?
Edited by oldninjaron on Sunday 20th September 15:29
Edited by oldninjaron on Monday 21st September 12:52
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