[10Arghh]

Hi guys,

I have upgraded my shock to a Bitubo unit and due to mount it (now that I've figured out which way round it goes...long story).

The bike will be used mostly on track soon and a lot of guys shim the OEM shock by 8mm to improve the bike's handling.

Is this mainly because the stock shock is too soft causing the bike to sit a bit low at the back or is this a general change that would improve the bike regardless of shock?

Also I remember from my GSXR1000 (yes totally different) that many were setting the forks to flush with the yokes (US: triple clamps) and also extending the rear wheel all the way back in the swinging arm.

Now this sounds counterintuitive for a quick steering bike, but it was done to improve the GSXRs stability and for me made a good improvement.

Is there anything like this with the 10R that can make improvements to the stability as that is what I prefer on track to give me confidence.

Thanks.

 

[Carlos76]

Gen4 geometry thread is great, hoping to learn here.

Not suspention expert, but have tested several settings on racing Gen4.
Experts say (and they are correct) that there are 20, 50 or 100 "issues" and parameters all connected and affecting sportbike handling.
To name few: rider preference, riding style, tyres, level, weight. This all can set certail numbers to one or other extreme.
But I like numbers and what those "ballpark" numbers are, for example for average trackday frend.

These are few basics to think with Gen4:

*Shimming shock.
Good swingarm angle somewhere at 12 degrees. If it is too flat then rear compresses too much with acceleration.
If too much angle then shock extends "locks up", rear wheel wants to drive under engine.
At an optimal angle the rear suspention works midstroke (or upper mid) under acceleration, follows road and gives good contact and grip.
Measure your aftermarket shock length and spring preload before shiming as these measurements affect shimming directly.
Tyre sizes, front position, axle position affect this angle too somewhat.

*Wheelbase.
Longer wheelbase gives stability, but Gen4 has enough wheelbase and stability (due to much trail at front).
Tried to run axle almost all the way back with additional chain link and did not like it: made steering harder, numb and felt like I needed more lean angle to make same corner at same speed.


*Trail.
Gen4 has big trail number making it very stabile.
To go fast on race track you need to twist bars with much more muscle force than with CBR1000R or S1000RR having trail on other end of spectrum.
Shimming shock and dropping front reduces trail, but you get pretty quick to point where other problems surface.
This may win some 5mm trail, but cannot get to 100mm trail number this way.
I think that the only way TO TRY to make Gen4 nimble is with adjustable offset triple clamps, as this affect trail directly without spoiling other parameters too much.
Numbers: With race tyre, stock 26mm clamp and 25deg rake the trail is somewhere at 110mm.
Ducatis (like 1098, 1199) have similar big 24.5 rake, but triple offset of 36deg and popular mod was put 30mm clamps.
Early S1000RR had trail somewhere at 90mm (twichy) with steep rake and 32mm!! offset and benefited from offset at 28mm.
I'm not sure what adjustable offset camps will do to Gen4, but I will definetly try them this summer.
And clamps that will allow at least 30mm.

*Weight distribution.
Several problems when front or back too low or too high.
Rider body position and moving on the bike, training is important.
Besides maybe there is something special about Gen4 center of mass (engine position) that makes it get away with big trail, wheelbase and still steering reasonable, I dont know.

*Dynamic action.
Things like compressing suspetion too much, too little or moving rates way off.
If bike geometry is ok and you have problems at corner entry then its mostly fork problem and at exit shock problem.
Sping rates, preloads, rebound, compression are realated to eachother and without little experience bad settings are often seen.
Have help from profeesional if thinking to go fast on track. This saves tyre money, makes predictabel handling, safer and faster.
There is long Dave Moss video in Youtube (Suspension Tuning - Dave Moss Masterclass) explaings all the basics.

 

[bbsteinnewyork]

Hi guys,

I have upgraded my shock to a Bitubo unit and due to mount it (now that I've figured out which way round it goes...long story).

The bike will be used mostly on track soon and a lot of guys shim the OEM shock by 8mm to improve the bike's handling.

Is this mainly because the stock shock is too soft causing the bike to sit a bit low at the back or is this a general change that would improve the bike regardless of shock?

Also I remember from my GSXR1000 (yes totally different) that many were setting the forks to flush with the yokes (US: triple clamps) and also extending the rear wheel all the way back in the swinging arm.

Now this sounds counterintuitive for a quick steering bike, but it was done to improve the GSXRs stability and for me made a good improvement.

Is there anything like this with the 10R that can make improvements to the stability as that is what I prefer on track to give me confidence.

Thanks.

www.suspact-na.com try this

Sent from my SM-G930V using Tapatalk

 

[10Arghh]

Gen4 geometry thread is great, hoping to learn here.

Thanks for detailed response Carlos...Seems you have done a lot of research with this bike.

My personal opinion, bearing in mind I haven't really tested the bike (no track day yet), it seems to turn in much quicker than the GSXR1000 K5. Running 190/55 rears on both, but different tyres and it's been over a year since I rode the K5.

I noticed this the first time I tried the 2011 ZX10R when it first came out.

Just something to get used to and I have already.

The front end feels wrong on my bike at the moment on stock suspension settings...Don't know how old the oil is but suspect its never been changed.

Pogo effect reacting to every bump and imperfection..Will try taking out some comp / reb damping.

Also could not get accurate sag setting.

Basically, the springs don't seem to react to weight being applied to them whether preload is taken all the way out or set all the way in.

All the way out, reduces the pogo effect slightly but there is still the damping problem.

The best I could do with the sag on the front was 22mm even with preload wound all the way in, also are the preload adjusters supposed to just keep spinning after they reach the max value on this bike?

Found that weird as the Ohlins R+T carts on my GSXR have a hard stop.

Anyway, so I think I need stiffer springs although the front feels rock solid and I'm wary of stiffening it further.

I have much work to do on the bike to set it up (slowed down by this charging system fault), but I believe the base is good as once settled in a turn feels very confident on the front.

This is all with using the stock shock at the moment as I have not fitted the Bitubo.

Need to fix all the electrical gremlins before tuning the bike.

 

[evallarta1]

Instead of guessing and speculating, lets just look at REAL numbers for the Gen 4 that I measured about a week ago.

A little about this bike. The suspension is 100% stock and the rider is racing with Pirelli Slick 120/70 and 200/60 slicks. While this affects geometry a bit the numbers won't be too far off from a bike on the showroom floor.

A couple things to notice -

-Trail is around 110mm. This means the front is very stable once in a corner, but entry into corners require more muscle to get in the corners.

- Rake is around 25 degrees, which is pretty good out of the box.

- Swing arm angle (swing arm down slope) is around 12 degrees. This isn't too bad, but add the long trail numbers and the bike has a tendency to drive wide on exit. Especially if the shock is under-sprung and/or heavy throttle is applied.

 

[evallarta1]

Next lets look at if we raise the rear.

Under the CMS measurement I add 20mm of ride height (approx 10mm at the shock).

This gives us a swing arm angle of 13.4 which in my opinion is a bit much. It also deletes trail almost 5 mil to 105.9, which again in my opinion is still a bit long. So with this setup the bike would turn much better, but the rider would probably complain about wheel spin while accelerating out of a corner.

 

[evallarta1]

So lets look at the other direction.

Here I lowered the front end by 10mm (Length front fork), or slide the tubes up in the triple by 10 mm.

You can see by lowering the front 10mm I really only deleted about 2 mm of trail. But look at the swing arm angle. I LOST almost a 1/2 of a degree of angle. So while the front end might feel a little better on entry, a rider will still complain about the bike driving wide on exit.

 

[evallarta1]

So what happens if we raise the rear 20 mm, and lower the front 10 mm. You can see we remove even MORE trail out of the front then either of the previous two, while not giving or losing too much swingarm angle.

I see a lot of guys here changing ride height front or rear without realizing why OR what else it affects. Also there are a BUNCH of other variables here, this is just scratching the surface but i figure this is a good visual to help people understand geometry.

 

[10Arghh]

This is great info

Think it should be made sticky.

So evallarta1 are you saying for most scenarios that the stock geometry can be left alone, if one just improves the rear soft shock that causes squat under acceleration causing the front to lift and the bike to run wide?

For my pace I believe that would work.

 

[evallarta1]

This is great info

Think it should be made sticky.

So evallarta1 are you saying for most scenarios that the stock geometry can be left alone, if one just improves the rear soft shock that causes squat under acceleration causing the front to lift and the bike to run wide?

For my pace I believe that would work.

I'll put it this way. If this were my bike, and I was doing anything but just cruising down the highway, I'd be figuring out how much trail to delete out of the bike.

 

[Carlos76]

Instead of guessing and speculating, lets just look at REAL numbers for the Gen 4 that I measured about a week ago.

A little about this bike. The suspension is 100% stock and the rider is racing with Pirelli Slick 120/70 and 200/60 slicks. While this affects geometry a bit the numbers won't be too far off from a bike on the showroom floor.

A couple things to notice -

-Trail is around 110mm. This means the front is very stable once in a corner, but entry into corners require more muscle to get in the corners.

- Rake is around 25 degrees, which is pretty good out of the box.

- Swing arm angle (swing arm down slope) is around 12 degrees. This isn't too bad, but add the long trail numbers and the bike has a tendency to drive wide on exit. Especially if the shock is under-sprung and/or heavy throttle is applied.

Oo my God. This is best post of the year.
Evallatra shares valuable insider info what you cannot find in Internet.
This gives solid point of understanding the Gen4 and more.
Many thanks.

 

[Carlos76]

Next ... I add 20mm of ride height (approx 10mm at the shock).
This gives us a swing arm angle of 13.4 which in my opinion is a bit much. It also deletes trail almost 5 mil to 105.9, which again in my opinion is still a bit long.

I go shopping Monday: "A set of those adjustable triple clamp for my Kawasaki please!"
Seriously.

 

[Carlos76]

Thanks for detailed response Carlos...Seems you have done a lot of research with this bike.

I only know that I know small fraction what professional people know. Start understanding something and you become aware how much is there that you don't know. I have many questions regarding bike handling to members like Evallatra or LDH, maybe I ask later as thread progresses.

 

[evallarta1]

I go shopping Monday: "A set of those adjustable triple clamp for my Kawasaki please!"
Seriously.

Yeah the biggest hurdle is there isn't enough room to drop the front end and not hit hard parts. You can get pretty close on the numbers, but putting on the triples can get things perfect.

 

[realpsi]

I will have to study this.

 

[sdiver68]

There is a big problem with the analysis. EV keeps saying the rider will complain about this and that. Since I know the rider, I know he only complains about being old and slow. :crackup:

 

[skidooboy]

thanks for the tutorial EV!

where would one source a 10mm spacer, to add to the rear height?

sounds like the poor mans street bike acceptable set up for turning (think deals gap, or Ozarks type of riding) without buying offset triples, would be a 10mm spacer in the rear shock mount, and to expose 10mm more of the fork tubes?

it appears now approx. 4mm of tube is showing now (stock), are you suggesting 14mm total, or 10mm total fork tube showing?

again, thanks for the info. rep sent your way! Ski

 

[Carlos76]

thanks for the tutorial EV!

where would one source a 10mm spacer, to add to the rear height?

sounds like the poor mans street bike acceptable set up for turning (think deals gap, or Ozarks type of riding) without buying offset triples, would be a 10mm spacer in the rear shock mount, and to expose 10mm more of the fork tubes?

it appears now approx. 4mm of tube is showing now (stock), are you suggesting 14mm total, or 10mm total fork tube showing?

again, thanks for the info. rep sent your way! Ski

Think that Evallatra is not directly suggesting 10mm shim (+20 raise) and droping front too much, but just showing what other numbers those adjustments would affect??
Bike would lift rear wheel easy with changes that much and problems having weight bias.
Offset triples are maybe last toutch to get bike perfect after suspention is well sorted. Do I really NEED them: probably no. Do I WANT them to test out: hell yeah.

Wasn't good member Dricked using aftermarket triples on his race Gen4? Wonder what's was his experience.

 

[Carlos76]

Pogo effect reacting to every bump and imperfection..Will try taking out some comp / reb damping.

Also could not get accurate sag setting.

Basically, the springs don't seem to react to weight being applied to them whether preload is taken all the way out or set all the way in.

All the way out, reduces the pogo effect slightly but there is still the damping problem.
...
Anyway, so I think I need stiffer springs although the front feels rock solid and I'm wary of stiffening it further.

Should all be easy fix:

*Pogo. Probably very little rebound damping. There are thin white seals in BPF, when damaged rebound is lost.

*Sag. Forget about sag, Gen4 has long topout springs preventing reaching "old school" sag numbers. Have correct springs for you weight and reasonable preload, then no need to measure sag.

*You wanna stiffer spings? What's you weigth? Are you bottoming or where is zip tie pushed when you do that test?

*Gen4 has compression adjuster and bypass (TEN) affecting both compression and rebound.

 

[ukzx10r]

Good thread.
I have something to add. I am 6 foot 4 tall and weight 15 stone which is a bit heavy for fast riding.
However im always quite fast on track but this comes with a few issues for me.
I always have issues with corner exit and always suffer with terrible rear tyre wear on every bike ive had on track.
Mines a gen4 and i found it terribly unstable. Always shaking its head and getting into some odd shapes.
Ive designed the damper valves to replace the motor and its cured the unstable feeling all together and ive lengthened the chain and it might have made a fraction of difference.
Next thing im going to do is fit linier link. Fit a stiffer rear spring and drop the front and raise the rear.
My front wear is absolutely spot on but because the rear is soo bad i am hoping to take a bit if wear off it and transfer it to the front.
I will watch this thread for more info