Dove
productively obsessed
Wouldn't steering be faster? As he increases rake, doesn't steering slow down?
Not opinions...questions -
-
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Sometimes you're the bat in life. Other times, the ball.
- Thread starter GoGo
- Start date
Wouldn't steering be faster? As he increases rake, doesn't steering slow down?
Not opinions...questions -
Depends on whether we're talking about before, or after the new triples.
Yes, steep means less trail which quickens steering but creates instability and gives you less feel/feedback - all of which we had in spades out there.
Like anything else it's a critical balance. To gain a little here you have to give a little there. We had way too much "here" and nothing at all "there". If anyone remembers Pat ripping by us at Buttonwillow to steal the checker, they might also remember our bike tying itself in knots as we simply powered down the front straight. I think that was due to the steep front end as well. Both bikes are steep but the R we got is ridiculous.
I hope with 15mm more height in the front, which Gerry estimates will get us to @ 102-4 trail, the bike actually steers slow (and stable). I would rather error on the side of too much trail, and simply deal with the slower steering, with the hope to be able to push the front around corners rather than instantly lose it. Those wide bars offer a lot of leverage..
Thanks a lot for your responses. I find this process fascinating, and I love having hard numbers to support your theories rather than simply seat-of-the-pants guesses. I've got a LOT of experience guessing and I rarely get it right.
Yes, steep means less trail which quickens steering but creates instability and gives you less feel/feedback - all of which we had in spades out there.
Like anything else it's a critical balance. To gain a little here you have to give a little there. We had way too much "here" and nothing at all "there". If anyone remembers Pat ripping by us at Buttonwillow to steal the checker, they might also remember our bike tying itself in knots as we simply powered down the front straight. I think that was due to the steep front end as well. Both bikes are steep but the R we got is ridiculous.
I hope with 15mm more height in the front, which Gerry estimates will get us to @ 102-4 trail, the bike actually steers slow (and stable). I would rather error on the side of too much trail, and simply deal with the slower steering, with the hope to be able to push the front around corners rather than instantly lose it. Those wide bars offer a lot of leverage..
Thanks a lot for your responses. I find this process fascinating, and I love having hard numbers to support your theories rather than simply seat-of-the-pants guesses. I've got a LOT of experience guessing and I rarely get it right.
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Dove
productively obsessed
It's been educational watching you dissect this whole event. Honestly - it's given me a good template for analyzing my own "moments."
Thank you for being so open about the whole experience. Gerry's video was eye opening and full of great info if you've got google open while watching.
This thread and that video will do wonders for his business, I'm saving up pennies to visit him as a direct result.
Thank you for giving a new racer the opportunity to see how it's done right.
Thank you for being so open about the whole experience. Gerry's video was eye opening and full of great info if you've got google open while watching.
This thread and that video will do wonders for his business, I'm saving up pennies to visit him as a direct result.Thank you for giving a new racer the opportunity to see how it's done right.
jrace
MotoGPhreak
Will just that give you the increased swingarm angle as well, or is that another challenge?
-jim
One of the things Phil did to our rear shock was shorten it, to lower the rear - effectively "raising" the front, in the hopes to get more trail. Another idea aimed in the right direction, but I think this cost us something as well - ground clearance and swingarm angle, which brings us into a whole new dimension of suspension theory.
Hold onto your balls for this hair brained explanation:
If your swingarm rotates on an axis up front, which it does - up and down, putting a pencil through your rear axle and letting the swingarm travel through its stroke would effectively draw part of a circle on the wall. Draw another line on the wall, horizontal, from the swingarm axis point to the outer edge of the circle. Now take a green crayon and color all of the circle from the horizontal line down - green. Take a red crayon and color all of the circle from the horizontal line up - red.
If your swingarm angle is 12 degrees, that means it's 12 degrees from horizontal, aimed downward into the green, which is good. Apparently you want your swingarm traveling ONLY in the green area - below the horizontal line. The reason for this is when a bump compresses your rear suspension, as long as it travels in the green it is sending the upward energy of compression away from your chassis. But as soon as your swingarm travels above the horizontal line, and into the red, now all that upward energy of compression is being sent INTO your chassis. As you know, "something" is going to absorb that bump you just hit, or the G-forces you just created by going through a turn (like turn 3). So the next likely candidate to absorb the energy is actually your front forks.
That's right, without enough angle to your swingarm hitting a bump with your rear tire will compress your forks. And in the case of poor little Jonny with his tricycle forks already way too steep going into turn 3, just the G-forces of that rise alone could have come through the swingarm, compressed the forks, and effectively instantly eliminated all the trail there was going into the turn.
How fascinating is THAT?
So Jrace, yes, by lowering the forks we will basically be lifting the whole front of the bike up - which will effectively raise the axis point of the swingarm and increase it's angle.
Hold onto your balls for this hair brained explanation:
If your swingarm rotates on an axis up front, which it does - up and down, putting a pencil through your rear axle and letting the swingarm travel through its stroke would effectively draw part of a circle on the wall. Draw another line on the wall, horizontal, from the swingarm axis point to the outer edge of the circle. Now take a green crayon and color all of the circle from the horizontal line down - green. Take a red crayon and color all of the circle from the horizontal line up - red.
If your swingarm angle is 12 degrees, that means it's 12 degrees from horizontal, aimed downward into the green, which is good. Apparently you want your swingarm traveling ONLY in the green area - below the horizontal line. The reason for this is when a bump compresses your rear suspension, as long as it travels in the green it is sending the upward energy of compression away from your chassis. But as soon as your swingarm travels above the horizontal line, and into the red, now all that upward energy of compression is being sent INTO your chassis. As you know, "something" is going to absorb that bump you just hit, or the G-forces you just created by going through a turn (like turn 3). So the next likely candidate to absorb the energy is actually your front forks.
That's right, without enough angle to your swingarm hitting a bump with your rear tire will compress your forks. And in the case of poor little Jonny with his tricycle forks already way too steep going into turn 3, just the G-forces of that rise alone could have come through the swingarm, compressed the forks, and effectively instantly eliminated all the trail there was going into the turn.
How fascinating is THAT?
So Jrace, yes, by lowering the forks we will basically be lifting the whole front of the bike up - which will effectively raise the axis point of the swingarm and increase it's angle.
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There exists a happy medium between quick steering (and less trail) to off corner stability and steering...I fought with it all weekend. I also know as we got REALLY steep, I'd lose even steerability, towards the end of negative trail. I suppose my question was did it ever get that steep where you lost steering at any point?
I'm not exactly sure what you mean by "lose steering". I definitely lost feel, and stability, but if you mean like understeer on a car - where the front wheel turns but the bike just keeps going straight - yeah, while I was on my chin.
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Haha! Feel and stability was where I was at...
KimDN
Pineapple Mafia godfather
When I raced my 05 GSXR1000, the higher I went with the front, the better it felt in every way. Hell it even steered lighter every time I went taller! go figure that one.
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Oh I know all about Kim and wanting to raise the front...Kim, Got miles..how many ya need? You bring me AND Eric some Toffee Macs? Make sure to give Eric his ONLY if we manage to sneak by him!
Eric,
You guys may all ready be on this, but you haven't mentioned it, so I don't know if you're aware, but there is an adjustable clevis available for the SDR's WP shock. The little sucker is expensive, ~$500 retail, but hey, racing is racing
Give you that additional ride height to get your pills off the ground, and more swing arm adjustability than the triples alone. Good thing maybe if you're thinking about going to softer spring rates / compression at both ends IMHO.
Looking forward to seeing you hooked up at the next round.
Ed
PS (I want a set of the Nichols triples please!)
You guys may all ready be on this, but you haven't mentioned it, so I don't know if you're aware, but there is an adjustable clevis available for the SDR's WP shock. The little sucker is expensive, ~$500 retail, but hey, racing is racing
Give you that additional ride height to get your pills off the ground, and more swing arm adjustability than the triples alone. Good thing maybe if you're thinking about going to softer spring rates / compression at both ends IMHO.
Looking forward to seeing you hooked up at the next round.
Ed
PS (I want a set of the Nichols triples please!)
Attachments
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com3
highside surprise!
dude... you were SOOOOO fucking lucky right there... 3rd bike back, and somehow, someway, you nor the bike got completely fucking derailed... i think you just mighta been the bat with that one, bro!
ps - i've NEVER seen anyone crash like that in 9a before.
Tell you the truth, I had no idea such a part even exists. I've forwarded your post to the boys at Tri Valley Moto. The last thing I want to do to this bike is RAISE the rear, but you are right, going softer may need starting higher. We'll have to play around.. Thanks for bring that up. A lot, thanks. Keep em coming!
Com3, I've been running around quite a while now. I've never crashed like that before. I think a good part of the reason no one hit us is because exactly that - it was such an odd place to be on the deck. Imagine how I felt? WHAT THE F.....!!!
Z3n
Squid.
Gogo,
Thanks for posting this entire process...I'm with Dove in that it really, really helps me to understand the interaction between the various parts of the motorcycle. I've got some books on chassis design that I've been trying to get through, but it's difficult to translate a bunch of numbers to what you feel/experience in the real world. This entire thing is fascinating, and I'm going to be playing with a tape measure and my motorcycle once I get the front forks back. Sucks that you had to crash, but thanks for sharing the process of discovering the whats and whys with us
Thanks for posting this entire process...I'm with Dove in that it really, really helps me to understand the interaction between the various parts of the motorcycle. I've got some books on chassis design that I've been trying to get through, but it's difficult to translate a bunch of numbers to what you feel/experience in the real world. This entire thing is fascinating, and I'm going to be playing with a tape measure and my motorcycle once I get the front forks back. Sucks that you had to crash, but thanks for sharing the process of discovering the whats and whys with us
Ok here's another lead- Looks like a very robust set of triples in the same offset configuration as the standard SD, AND with twice the amount of fork coller on the tops (two bolts). Ignore the stearing stabilizer & bar riser gizmos, and feast your eyes on the hunky double-nut top clamp. In combination with the shock cleavis, these should provide enough ride hight / angle adjustment at both ends to get you managable geometry. Don't know how far along you are with Nichols or what their price are for creating new part, but this is certainly worth looking into.
http://www.emigracing.com/
SD-R's Rule!, or Suck, or... Whatever, yeah.
Ed
edit to attach pic-
http://www.emigracing.com/
SD-R's Rule!, or Suck, or... Whatever, yeah.
Ed
edit to attach pic-
Attachments
We just ran our standard superduke at Infineon with Reg Pridmore's school. Phil slid our forks half way down into those stock triples. What a better bike. Raising the front of a Superduke is totally the way to go. I can't wait to run the R with the new triples.
By the way those triples look cool but I bet it's a bitch turning in more spring - with an open end wrench UNDER the bars and down into the hole those clamps would create once you slid the forks down into them. Just wait for Nichols to finish what they're creating. My bet is it'll rock!
Thanks for the research man. We'll get this thing going..
By the way those triples look cool but I bet it's a bitch turning in more spring - with an open end wrench UNDER the bars and down into the hole those clamps would create once you slid the forks down into them. Just wait for Nichols to finish what they're creating. My bet is it'll rock!
Thanks for the research man. We'll get this thing going..
KimDN
Pineapple Mafia godfather
Any other changes besides the fork height?
This was the old bike, which wasn't as steep in the front but does share similar traits to the R. I knew going in that the day had a glass ceiling on it since we don't have the Nichols triples yet, but Kari (owner of Tri Valley Moto's older brother store in Mountainview - Cal Moto) used to actually sponsor Reg Pridmore waaaay back in the day so he got us in the back door.
By pushing the forks down into the top triple we did confirm this is the direction to go. The bike was a bit more stable, but the best part was this opened the door to softening up the front with valving again (which is how we had to keep the front tall before). Once a bit taller in the front we backed all the way out to the soft end of our adjustment window the way Phil built them for Buttonwillow. Turns out now that was still too stiff. To try to get better balance than we had before we ended up, after many sessions of adjusting, all the way maxed out on the rear shock on compression. We're still not balanced though, the front is still stiffer than the rear, and the bike still does not react to input the way we want it to. Instead of the bike working "with you", we kind of have to work "around IT". But we are definitely progressing in the right direction. And we do have an idea of which way to keep going, and how we will get there.
Later in the day we came up on Rich Oliver out there on an R6. We went into the Carousel handlebar to handlebar, us on the inside. Our hands hadn't been that close in two decades, when I was introduced to him somewhere back in the late 80s in a restaurant in Daytona. He wore glasses back then, looked like a school boy, probably weighed 119lbs, and ate salad like a bird as he sat next to the King, Kenny Roberts himself. Rich's whole career was in front of him. I was just there to watch.
It was mostly street riders out there yesterday so I thought maybe he'd enjoy a change of pace and perhaps taking a few stabs at our Superduke. We eased by on his inside at the entrance, shimmied a little mid turn, and then took off up the hill and into seven. He didn't bite though - I never saw him again. But he did come by our pit later, with a gaping wide laughing grin on his face. "Wow you guys really look like you're dialed out there!" We all just looked at each other and answered in somewhat of a chorus, "Well..... not exactly."
By pushing the forks down into the top triple we did confirm this is the direction to go. The bike was a bit more stable, but the best part was this opened the door to softening up the front with valving again (which is how we had to keep the front tall before). Once a bit taller in the front we backed all the way out to the soft end of our adjustment window the way Phil built them for Buttonwillow. Turns out now that was still too stiff. To try to get better balance than we had before we ended up, after many sessions of adjusting, all the way maxed out on the rear shock on compression. We're still not balanced though, the front is still stiffer than the rear, and the bike still does not react to input the way we want it to. Instead of the bike working "with you", we kind of have to work "around IT". But we are definitely progressing in the right direction. And we do have an idea of which way to keep going, and how we will get there.
Later in the day we came up on Rich Oliver out there on an R6. We went into the Carousel handlebar to handlebar, us on the inside. Our hands hadn't been that close in two decades, when I was introduced to him somewhere back in the late 80s in a restaurant in Daytona. He wore glasses back then, looked like a school boy, probably weighed 119lbs, and ate salad like a bird as he sat next to the King, Kenny Roberts himself. Rich's whole career was in front of him. I was just there to watch.
It was mostly street riders out there yesterday so I thought maybe he'd enjoy a change of pace and perhaps taking a few stabs at our Superduke. We eased by on his inside at the entrance, shimmied a little mid turn, and then took off up the hill and into seven. He didn't bite though - I never saw him again. But he did come by our pit later, with a gaping wide laughing grin on his face. "Wow you guys really look like you're dialed out there!" We all just looked at each other and answered in somewhat of a chorus, "Well..... not exactly."
I let the forks down ~7mm in the SDR yesterday, and the bike feels stable and tracks better mid corner. I'd like to try going further, but feel apprehensive as the collars are so shallow. Fork tops are ~4mm below the top of the triple, and spring adjustment IS going to require removing the bars and using a socket wrench. So basically, its going to be a set it once and forget it proposition. I would be very interested to get Gerry's measurements for trail, and swing arm angle with this adjustment alone.
Suspension wise, the SDR stock front end feels over sprung and over damped for my weight and typical riding conditions (street & occasional track day). I'm 170LBS in gear and can get ~1"-1.125" sag at either end but the ride is really harsh. The bike is better when ridden @ 9/10ths on smooth pavement, but being a street bike that is only a small % of the time. I had the compression side of the shock shimmed softer but stayed with the same spring rate. Result was less harsh but now the rear isn't balanced with the front end at all, even with increased bump dampening. I'd like to go down a spring rate at both ends and see what that does.
Thanks for sharing your R&D Go-Go, I'm appreciating the trickle down effect.
Suspension wise, the SDR stock front end feels over sprung and over damped for my weight and typical riding conditions (street & occasional track day). I'm 170LBS in gear and can get ~1"-1.125" sag at either end but the ride is really harsh. The bike is better when ridden @ 9/10ths on smooth pavement, but being a street bike that is only a small % of the time. I had the compression side of the shock shimmed softer but stayed with the same spring rate. Result was less harsh but now the rear isn't balanced with the front end at all, even with increased bump dampening. I'd like to go down a spring rate at both ends and see what that does.
Thanks for sharing your R&D Go-Go, I'm appreciating the trickle down effect.
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KimDN
Pineapple Mafia godfather
On our GSXRs, to get more front height, we would sometimes remove one of the steering stem locknuts so the triple would sit lower. Not sure if the SDR has two locknuts, but that's a way to gain a few more mm. If you do this, make sure the triple is sitting flush the way it's supposed to--we had to add a 2mm shim, but that still gave us an additional 4mm.