Gearing Change Strategy

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Best photo I could find of the WSBK swingarm hub. They still use the eccentric hub, which seems kind of crazy since it seems to muddy the water so much. You’d think they could engineer a way to make the axle travel in a linear path to simplify suspension setup. I guess this problem is what keeps the suspension engineer employed.

1662926957762.jpeg
 
RickD996 said:
It all depends on what point of the hubs movement you start at, and end at. Some one tooth increments will effect ride height more, and wheelbase less, and vice versa etc.
In my instance, it effected ride height by 11mm, which was corrected by 2mm shock length adjustment. I didn't have time to check the wheelbase unfortunately.
Click to expand...

@RickD996 how did you know to shorten shock by 2mm to compensate for 11mm ride height increase?
 
Wito said:
@RickD996 how did you know to shorten shock by 2mm to compensate for 11mm ride height increase?
Click to expand...

@Wito I have a ride height tool, but you just need two fixed points to measure between. One on the chassis, and one on the swingarm. Take a measurement before changing gearing, and once after (this gave me 11mm difference).
Then, unfortunately you need to remove the shock (although not a big job). Lengthen the shock, 1mm at a time, reinstall and remeasure ride height, until you get the desired figure. If, say, you get to within a mm, or so, then you can use preload to fine tune the ride height. Also, you can, obviously, take the shock out and alter the length by less than a mm.
 
@RickD996 Thank you for great info! As far as I know it was 1mm shock to 2.5mm ride height but I will measure from swingarm to rear subframe.
I run Ohlins FL956 front ant Ohlins TTX rear - hard to get this setup working. Front SAG is 40mm and rear SAG is 30mm. Ohlins TTX is 312mm and I find the bike front-heavy.... I guess ride height is too big, because I run 15t front sprocket, so my wheelbase is bigger and eccentric hub increasing height.
 
Wito said:
@RickD996 Thank you for great info! As far as I know it was 1mm shock to 2.5mm ride height but I will measure from swingarm to rear subframe.
I run Ohlins FL956 front ant Ohlins TTX rear - hard to get this setup working. Front SAG is 40mm and rear SAG is 30mm. Ohlins TTX is 312mm and I find the bike front-heavy.... I guess ride height is too big, because I run 15t front sprocket, so my wheelbase is bigger and eccentric hub increasing height.
Click to expand...

@Wito Yes, I initially added 5mm to my shock, but the ride height increased by a lot more than the desired amount (11mm). So, I kept reducing the shock length. Was surprised that only 2mm was required. But, I've ridden the bike, and remeasure, and, the ride height is correct.
I don't take sag figures unfortunately, and never have, so can't comment on them unfortunately!
What do you mean by 'front heavy'? Does the rear spin easily, and the bike's not especially stable under braking? You could definitely try lifting the front, or dropping the rear. I tried lifting the front, and the bike felt good, and I started increasing the rear ride height too. I could never get the bike perfect. It would either be brilliant on the front, but no traction at the rear. Or, vice versa. When I started lowering the bike, things really started improving. I ended up with upto eight mm of fork showing, and the shock at 308mm. The bike felt at its best, but not perfect. So started lifting the front, until the forks were flush, with about 8mm preload. I didn't want to lift the front further, so lowered the back further. Took the shock to 306mm. Bike is amazing.
It's worth playing around with the ride height!
It's a shame there's no way of easily measuring the hub position.
 
@RickD996 These are exactly my observations too! Which I came to by trial and error. Right now my forks are almost flush (1-2mm) and I started to lower the rear..... That's why I was asking you the questions about the rear - how much lower to go.
Too front-heavy - I mean it's very unstable on brakings, struggling with rear traction on exits. My rear is 312mm right now, I will measure ride height and try around 308mm - then decide where to go from there.

I am 92kg and other thing I am working on currently are springs. I changed front to 10.5 and I will go for 11. (heavy braker) Rear changed to 105 and experimenting with 110.
 
Wito said:
@RickD996 These are exactly my observations too! Which I came to by trial and error. Right now my forks are almost flush (1-2mm) and I started to lower the rear..... That's why I was asking you the questions about the rear - how much lower to go.
Too front-heavy - I mean it's very unstable on brakings, struggling with rear traction on exits. My rear is 312mm right now, I will measure ride height and try around 308mm - then decide where to go from there.

I am 92kg and other thing I am working on currently are springs. I changed front to 10.5 and I will go for 11. (heavy braker) Rear changed to 105 and experimenting with 110.
Click to expand...

@Wito keep going until it feels you've passed the sweet spot!
I'm at 10.75 front, but will be going to 11 at the next circuit I'm on.
I've got a 90Nm in the shock. Started at 105.

I also found, when my bike was 'tall' (high front, high rear), quite unstable.
 
@RickD996 You started with 105 at the rear and went down to 90? That's interesting! Why? What shock and how much do you weight?
I started with 100 and went up to 110.
 
Wito said:
@RickD996 You started with 105 at the rear and went down to 90? That's interesting! Why? What shock and how much do you weight?
I started with 100 and went up to 110.
Click to expand...

Just didn't have much feel with the stiffer spring, or edge grip. Bike felt better the lighter I went with the rear spring. I used to have Ohlins, then Mupo, but now on Maxton. I'm 80kg.
Are you racing in Poland or UK? Or somewhere else?
 
@RickD996 I see - I will probably try with lighter spring again (as far as I can maintain proper sag).
Usually Central Europe (Poland, Czech, Slovakia, Hungary etc.) Sometimes winter trainings in Spain - we shared some trackdays with guys from UK (nolimits, redline)
 
andyb said:
I made mine..
Barni racing wanted silly money for one.
View attachment 44397
Click to expand...

I would ditch the oem zip tie location for mounting the wiring for the Gear sensor and Quickshifter, over time my wires had melted and the rubber insulation deterioated inside from being so close to the exhaust. On the street, probably not big deal, but for a track bike, it gets really hot. I just rasied the wiring and ran them right under the stator and kept it high and tight.
 
elements018 said:
I would ditch the oem zip tie location for mounting the wiring for the Gear sensor and Quickshifter, over time my wires had melted and the rubber insulation deterioated inside from being so close to the exhaust. On the street, probably not big deal, but for a track bike, it gets really hot. I just rasied the wiring and ran them right under the stator and kept it high and tight.
Click to expand...

ive actually gone back to the std QS now and I find its feel superior to the HM one...and moved the wiring.
 

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