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post #1 of 48 Old 10-13-2019, 11:03 AM Thread Starter
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I had been having issues with not having enough weight on the front and not getting good turn in and the tire wouldn't warm up. The easiest thing to do was to lengthen the shock at the bottom clevis and I raised it about 2mm from stock length and adjusted rebound/ compression on the front and it solved my issues. I heard a couple of people at the track suggesting to adjust the forks first. So what is the difference between raising the rear and dropping the front? Wouldn't there be a similar effect with swingarm angle and rake?

What's a good baseline for 13+(includes 19+ ) models?

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post #2 of 48 Old 10-13-2019, 11:56 AM
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I had been having issues with not having enough weight on the front and not getting good turn in and the tire wouldn't warm up. The easiest thing to do was to lengthen the shock at the bottom clevis and I raised it about 2mm from stock length and adjusted rebound/ compression on the front and it solved my issues. I heard a couple of people at the track suggesting to adjust the forks first. So what is the difference between raising the rear and dropping the front? Wouldn't there be a similar effect with swingarm angle and rake?

What's a good baseline for 13+(includes 19+ ) models?
Mathematically there is a difference but I couldn't tell you what without doing a bunch of measurements and calculations. 2 mm change on the shock length has a different effect to rake/trail/swing arm angle than 2 mm change on the forks. It varies by bike too all based on how the shock is mounted, the linkages used (if any), etc. Tough question to answer exactly.

The other thing it affects is overall ride height. Do you want to have a higher rear end or a lower front? In theory it's possible to achieve the same rake/trail/swing arm angle setup by only adjusting rear height as you would by only adjusting the front height, but then the difference is in the height. With one setup you'll have a higher overall height than with the other which affects your center of gravity.
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post #3 of 48 Old 10-13-2019, 12:26 PM
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Man, seems like you and I mess with the suspension a lot.

From what I was told the biggest difference between raising the back and lowering the front to get overall better turn in is ground clearance. The stability difference between raising the rear versus dropping the front is minimal. I have heard that you should focus on raising the rear before lowering the front for what it is worth. I have raised the rear 3/16" which put my seat 11mm higher. Planning on going another 3/16" and see how it works out at the next track day. Then maybe drop the forks a couple mm's and so on until the bike becomes unstable. Then back out 1 move. But I want to raise the rear twice before I lower the forks to keep my seat height up and keep ground clearance as high as possible.

I had a buddy on an R6 show me some measurements he took when messing with his geometry. Making the same move in the rear and the front (raising the rear, lowering the front). He was able to get ~0.5 degrees more lean by raising the back, and ~0.5 degrees less lean by lowering the front.

Hope this helps.
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post #4 of 48 Old 10-13-2019, 02:53 PM
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From what I have seen, a lot of people raise the rear (add shims) as a standard practice for track duty.

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post #5 of 48 Old 10-13-2019, 06:08 PM Thread Starter
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Forgot I had this. Reading it up right now.
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post #6 of 48 Old 10-13-2019, 09:25 PM
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Do you know what your swingarm angle is?
rake?
trail?

Those are pretty important numbers to know to really start making changes......

3 different bikes, 3 different results- 3 different riders liking somehting different.....but generally 10-12* swingarm angle is the sweet spot
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Stupid people say stupid things on the internet, so be wary of who those people are. If you solicit advice on the internet, just keep in mind 99% of what you'll receive is not based on fact or science-and likely atleast 95% of it is based on bullshit and bravado regurgitated from some other schlub who also did not experience any of what they claim and are also full of shit. If you don't like my bluntness- too bad. I am not here to please you, so move along, your approval is not desired nor is it needed. So before opening your pie hole and adding more stupidity, perhaps sit back, listen, absorb and learn something. You know that saying, it is better to remain silent and thought a fool than to open your mouth and remove all doubt!
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post #7 of 48 Old 10-14-2019, 11:31 AM
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Forgot I had this. Reading it up right now.
This is GREAT! Thanks for sharing.
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post #8 of 48 Old 10-14-2019, 03:25 PM
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So what is the difference between raising the rear and dropping the front? Wouldn't there be a similar effect with swingarm angle and rake?
The biggest difference is that raising the rear also affects where you sit in the linkage curve for rear suspension response and the chain pull angle, which affects rear squat under acceleration. For fast riders swingarm angle is a big thing to get right because it can have a major effect on handling when coming off corners.


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post #9 of 48 Old 10-14-2019, 07:51 PM Thread Starter
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Originally Posted by riverszzr View Post
Do you know what your swingarm angle is?
rake?
trail?

Those are pretty important numbers to know to really start making changes......

3 different bikes, 3 different results- 3 different riders liking somehting different.....but generally 10-12* swingarm angle is the sweet spot
Thanks. Just ordered a digital inclinometer.

JL99

Last edited by jd41; 10-14-2019 at 07:59 PM.
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post #10 of 48 Old 10-16-2019, 04:03 AM
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Is it legal in racing to change the shock linkage?

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post #11 of 48 Old 10-16-2019, 04:27 AM
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10* is very flat... running wide and having on the throttle steering issues will be forth coming. 12-13 is more in the range that works, especially for low powered 600's (including 636's over 125hp). I like about 12-12.5 so the rear just barely gets squirming when I squeeze on the gas at the apex.

Even on 200hp literbikes, they set the anti squat in this range. Once you past 13.5ish degree's rear edge grip starts to go away and you really need to have sensative throttle control to make it work. It's great fun on point and shoot tracks, but I've been thrown out of the seat using 5% throttle at over 55* lean with a 13*+ swingarm angle.
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post #12 of 48 Old 10-16-2019, 04:38 AM
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Is it legal in racing to change the shock linkage?
In Superstock classes, it's mostly not allowed. Check the organization rules to be sure. In Superbike classes, it's usually not an issue, bottom line, check with the organizations rules to be sure.
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post #13 of 48 Old 10-16-2019, 07:36 AM
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10* is very flat... running wide and having on the throttle steering issues will be forth coming. 12-13 is more in the range that works, especially for low powered 600's (including 636's over 125hp). I like about 12-12.5 so the rear just barely gets squirming when I squeeze on the gas at the apex.

Even on 200hp literbikes, they set the anti squat in this range. Once you past 13.5ish degree's rear edge grip starts to go away and you really need to have sensative throttle control to make it work. It's great fun on point and shoot tracks, but I've been thrown out of the seat using 5% throttle at over 55* lean with a 13*+ swingarm angle.

When measuring the swingarm angle: are we talking with the bike on itís own weight alone, or with the rider onboard? I would think that would make a difference.

Last edited by Duc995; 10-16-2019 at 07:40 AM.
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post #14 of 48 Old 10-16-2019, 08:02 AM
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This is the tricky part. You can't have the bike on stands OR on it's own weight to get an accurate measurement. The tires must be a hair off the ground to see the static angle.

Personally, I don't bother with this every time I change the angle. The first time, yes. However, after the initial setup I just make 1mm adjustments and see how it feels. Chasing numbers isn't going to make you faster unless you're at the sharp end of the white plate's.
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post #15 of 48 Old 10-16-2019, 08:37 AM
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This is the tricky part. You can't have the bike on stands OR on it's own weight to get an accurate measurement. The tires must be a hair off the ground to see the static angle.

Personally, I don't bother with this every time I change the angle. The first time, yes. However, after the initial setup I just make 1mm adjustments and see how it feels. Chasing numbers isn't going to make you faster unless you're at the sharp end of the white plate's.
It just seems like a dynamic number: bike off the ground/bike on the ground/rider on the bike/under acceleration/under deceleration - the number is constantly changing. Tough to chase a constantly changing number.
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