[Mog1290r]

My final answer - gearing does not depend on the rider height, but rider height depends on gearing. Nothing should prevent you from installing 20mm with stock sprockets and chain.

Here is an installation video -

. It's for the linkage kit but the first part applies as well.

Yip I'm running stock sprockets atm but I'm taking a 16t front sprocket with me to the track. Last year on the 16t front sprocket round Portimao I would not of wanted the gearing any shorter as it was a nightmare keeping the front wheel down as it is ,,, the bike still wheelies easily with the +20

 

[GJB]

My final answer - gearing does not depend on the rider height, but rider height depends on gearing. Nothing should prevent you from installing 20mm with stock sprockets and chain.

Or said differently to respond to the original question, the chain tension is a function of gearing, not linkage.

 

[KiwiEd]

Yip I'm running stock sprockets atm but I'm taking a 16t front sprocket with me to the track. Last year on the 16t front sprocket round Portimao I would not of wanted the gearing any shorter as it was a nightmare keeping the front wheel down as it is ,,, the bike still wheelies easily with the +20

I used 16/40 when I raced a few weeks ago but also used a 114 link chain which is key to stopping the wheelies, I basically had zero issues. I also have GoGo's suspension link set at 30mm which gives amazing turn in and tight drives out, this is where I could make passes, ie late braking, turn in hard and stay tight ... what a buzz !!! I will be using a 16/41 for future racing as I found that the 40 didn't offer quite enough drive ( I didn't have a 41 with me). Bearing in mind that the main gear for exciting a tightish corner was 3rd and 4th for the sweepers. This meant that 6th was able to be used on the straights and aided in getting to a reasonable top speed relatively quickly.

 

[Somefun]

I used 16/40 when I raced a few weeks ago but also used a 114 link chain which is key to stopping the wheelies, I basically had zero issues. I also have GoGo's suspension link set at 30mm which gives amazing turn in and tight drives out, this is where I could make passes, ie late braking, turn in hard and stay tight ... what a buzz !!! I will be using a 16/41 for future racing as I found that the 40 didn't offer quite enough drive ( I didn't have a 41 with me). Bearing in mind that the main gear for exciting a tightish corner was 3rd and 4th for the sweepers. This meant that 6th was able to be used on the straights and aided in getting to a reasonable top speed relatively quickly.

When you run the 41 are you going to run the same 114 link Chain? I run the link 20” mm and the 17/40 and I’m pretty happy with it for the street.

 

[KiwiEd]

When you run the 41 are you going to run the same 114 link Chain? I run the link 20” mm and the 17/40 and I’m pretty happy with it for the street.

I will definitely run the 114 when I go 16/41, it can't be longer as there will be no adjustment left. For the street, which in my case is mostly just twisty and bumpy back country roads, (where I live), I'll just use 16/40. But, tbh, after tracking it, I'm almost inclined to leave it as a track bike, the road will seem so boring lol.

 

[Whiskey Tango Foxtrot]

Wondering if anyone has taken tire profile into consideration when lifting the rear end up ? I think (and I may be wrong) the stock rear tire 200/55/17 will give you "X" for measuring the height of the rear. I'm now running a 200/60/17 that has brought the rear height up probably another 10-15 mm (not sure ,but when I put the tires side by side , the 60 was defiantly higher) So ,one might be able to achieve a taller ride height just by going to a taller profile and not need the magic link ? Just a thought boy's and girl's,mull it over and share your wisdom .

 

[Panzerlang]

Wondering if anyone has taken tire profile into consideration when lifting the rear end up ? I think (and I may be wrong) the stock rear tire 200/55/17 will give you "X" for measuring the height of the rear. I'm now running a 200/60/17 that has brought the rear height up probably another 10-15 mm (not sure ,but when I put the tires side by side , the 60 was defiantly higher) So ,one might be able to achieve a taller ride height just by going to a taller profile and not need the magic link ? Just a thought boy's and girl's,mull it over and share your wisdom .

I think the point at which the rear's being raised makes a huge difference. At the wheel axle vs at the swingarm's pivot, especially via the linkage there. It changes the way the spring works.

 

[KiwiEd]

55% x 200 = 110, 60%x200=120. Diff in ride height is therefore 10mm. Obviously placing tyres next to each other the 60 will be 20mm higher. You have a good point though. I'm not sure what the diff is BTW a new and used tyre but that would also affect ride height as it wears. Getting pretty techo though, way above my level of sensitivity to change.

 

[Whiskey Tango Foxtrot]

I think the point at which the rear's being raised makes a huge difference. At the wheel axle vs at the swingarm's pivot, especially via the linkage there. It changes the way the spring works.

Yes, but we're not measuring the axle height.......we're measuring a point on the subframe/tail section.....and 10 mm is 10 mm.....no ?
Got to agree with Kiwi Ed at this point.

 

[GJB]

The ride height reference is measured from the axle to some arbitrary point above the axle with both wheels suspended, so that number does not change with tire size. Since we ride with the tires on the ground, the actual ride height is dependent on tire radius, not diameter of tire so if you switch to a tire with 5mm less radius you would need to add 5mm ride height to match. Ride height does 2 things to improve agility. raises CG which makes left to right transitions quicker, and secondly decreases the trail that makes turn in quicker. If you go above 20mm ride height you will have too little trail unless you change the triple clamp offset. Unless you want to start making other geometry changes going above 20mm will start creating other problems

 

[Whiskey Tango Foxtrot]

I stand corrected I though we were measuring from the ground to the tail section and not the AXLE to the tail section......thanks for that.

 

[KiwiEd]

The ride height reference is measured from the axle to some arbitrary point above the axle with both wheels suspended, so that number does not change with tire size. Since we ride with the tires on the ground, the actual ride height is dependent on tire radius, not diameter of tire so if you switch to a tire with 5mm less radius you would need to add 5mm ride height to match. Ride height does 2 things to improve agility. raises CG which makes left to right transitions quicker, and secondly decreases the trail that makes turn in quicker. If you go above 20mm ride height you will have too little trail unless you change the triple clamp offset. Unless you want to start making other geometry changes going above 20mm will start creating other problems

GoGo is currently developing an adjustable triple for precisely the reasons you mention. A protype has been made and is currently undergoing testing.
Personally, I often struggle to find setups that make a huge difference to handling, meaning the type that when I go out I think "wow, that's so much better".
That is probably largely due to the fact that I have never been a champion racer that pushes extreme limits, I do push but am always mindful of:
a/ my pride and joy under me b/ my business which would sink without me 12hrs/day and c/ my family.
However, with the adjustable link I did feel an immediate positive difference.
As an aside, a friend of mine has been involved in the MotoGP scene for decades, firstly with HRC and then head hunted by KTM when they started developing their MotoGP bike. He was telling me about testing where they experimented with torque settings on the front engine mount bolts, which, apparently, affect something in the handling. After one lap the rider came back in with the comment "are you trying to kill me". Obviously, the point is that it's the really fast guys that notice the slightest change in setup, the rest of us mere mortals tend to ride around the problems or not even detect them because we are simply not going fast enough. And, let's face it, I doubt that 99% of road riders ever get close to those sort of limits, and the other 1% are temporary lunatics.

 

[GJB]

I am using those adjustable triples

 

[KiwiEd]

I am using those adjustable triples

I suspected you were.

 

[lumpasaurus]

I am using those adjustable triples

So what is your ride height and trail that you are using? What do you think so far? In his latest video their is a glimpse of them if you look close, they look sic.

 

[GJB]

I have not settled on anything yet. The Stock geometry is not designed for racing and everything becomes a compromise. have not found an ideal race setting yet, and without the ability to raise/lower swingarm pivot it is impossible to dial in desired values for rake/trail/SA angle, ride height (need a real sport bike to do that). I have been around +30mm ride height, but that gives a ridiculous amount of swing arm angle/antisquat, that raises the rear on corner exit under acceleration causing the front tire to 'plow'. See attached pic of my torn front tire. So I am likely to go less ride height to reduce SA angle / antisquat.

Also, dont get hung up on the ride height numbers, they are only references based on a suspended bike without the wheels on the ground. For any particular bike if you get +10 or +20 it will raise your bike accordingly. But since tire size, rider weight, spring rate, and preload all play in the actual ride height when riding, you cannot make comparisons of ride height from bike to bike based on the linkage alone. I lighter rider without any linkages could actually have more ride hight that a heavy rider with +10 or +20mm. Similarly adding 5mm preload has the exact same affect on ride height as 10mm linkage, as will a heavier spring. So 2 riders with the same linkage do not really have the same geometry due to the other variables