R1 fishtailing

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tomngle

New Member
Hey Gents,

I have a problem on my 2006 R1 last season where the bike would fishtail under hard braking (i.e 1st turn at Summit). However, it feels solid on the turns. I had put a zip tie on a fork and notice I'm still have about 1 inch of suspension travel left, yet the bike is already fishtailing.

I weight at 135lbs. The front suspension is completely stock. I had my race sag set to about 27 mm (with the stock spring, 0.90kg/mm, set almost at full soft).

I'm planning on getting softer springs (0.85kg/mm) but still unsure if this is the right change.

Tom
 
Matt

Matt

New Member
What are your rear settings? Preload, comp and reb.

Wha are your fork damping settings?

What components have you changed?
 
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tomngle

New Member
The front setups are: preload close to full soft 7.5/8, rebound at 11/16, compression at 12/25.

The rear setups are: preload at 4/10 (30mm sag), rebound at 17/20, compression at 8/20.

Everything is stock. The only thing I tried was going stiffer on front compression: from 12/25 clicks to 9/25 clicks. That did not seem to help.
 
Emerson

Emerson

BobbleHeadMoto
Control Rider
ATP/3C
How smooth are you on down shifts? If I'm not mistaken the 06 didn't come with a slipper clutch. If you're not smooth it.could cause the rear to fishtail.
 
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tomngle

New Member
Okay, softening the rear preload is something I haven't tried.

To reply to Emerson:
It's definitely not a downshift problem. For example, as I brake for turn 1 at Main, the bike feels stable for a bit, and as the front slowly dives, it feels like the rear is coming up and I'm losing contact from the rear tire and the bike starts to fishtail. If I ease up or back off on the brake just a bit, then the bike is stable again.
 
Matt H

Matt H

New Member
Could be LOTS of things. Thing to realize is that the fishtailing from the rear is basically the rear end being light and allowed to drift under braking. If the front end is too soft - springs or compression - it will unload the rear. If the springs are too light, generally you would find yourself bottoming the fork. But maybe compression is too light and thus blowing through the stroke. Also, rear rebound could be too slow. What happens here is that as the weight is transfered to the front under braking, the rear is not extending fast enough to keep the wheel in contact with the ground. Could also be geometry - if the bike is already on its nose by geometry, hard braking will make fishtailing easy due to lack of weight in the rear. Also could be a bit of grabbing the brake too hard too fast. As in you should be setting the brake before going to full braking force. Grabbing the brake trying to brake late can make the bike dive way to quickly and unload the rear. These are just ideas and some factors. I would suggest having a suspension person look at it to see if anything is grossly out of whack, and from there work with you to see what needs to be changed.
 
bmart

bmart

Control Rider
Hey Tom,

Boy can people complicate things...

It seems like you just need to gain some weight and sit back a little! :)

Seriously, they're giving you some great advice. Turn a few screws (to feel what each change causes) during a track day once you get it in the ball park...and talk to the suspension guys in the trailer! It will be the best $40 or so you could spend.

brad
 
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tomngle

New Member
Haha, "gain some weight", I like that. I will definitely have to try these different setups and hook up with a tuner.

To reply to Matt: I'm not bottoming my forks out. Base on the zip tie, I still have 1 inch of travel left before bottoming. Could the front being too stiff cause the bike to not dive any further, hence lifting the rear?

Tom
 
Matt

Matt

New Member
i would suggest to take some rear rebound damping out.. I don't think you have a front end problem. You could brake harder.

What I think is happening is, when you're on the brakes, your rear is using the very last bit of extension it has. which means the spring is (sorta) running out of force, that rebound damping is tight so it takes the spring some time to come that, which means that over bumps the shock is absorbing the bump but then the rear wheel looses (or has very little) contact with the ground on the back side of the bump.


start simple.

My suggestion for your setup would be, softer springs, allowing more preload, then when you get quicker a proper shock / fork valve kit.
 
sobottka

sobottka

New Member
...too stiff springs/too much preload. soften it up (no more than 30mm pre-load to start, up to 35mm), use a little more fork travel and presto!
 
barry38

barry38

Member
tomngle;164014 wrote: Hey Gents,

I have a problem on my 2006 R1 last season where the bike would fishtail under hard braking (i.e 1st turn at Summit). However, it feels solid on the turns. I had put a zip tie on a fork and notice I'm still have about 1 inch of suspension travel left, yet the bike is already fishtailing.

I weight at 135lbs. The front suspension is completely stock. I had my race sag set to about 27 mm (with the stock spring, 0.90kg/mm, set almost at full soft).

I'm planning on getting softer springs (0.85kg/mm) but still unsure if this is the right change.

Tom
Click to expand...
Before advising that you make any changes, I want to know a little bit more info. What group are you in? How much side-to-side deflection? How smooth is your braking? Does it only happen in Turn 1 at Summit, or is it an issue elsewhere? Summit Turn 5 maybe? Have you had anyone follow you to see this? Are you 135 lbs in riding gear???

In my opinion some "squirming" under hard braking is normal. I'd want to make sure your having a real issue before you start making changes, especially since you are not having other handling issues. Realistically, the bike is probably sprung to stiff at both ends for your weight, and I'd address that before you start changing the dampening.
 
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tomngle

New Member
Thanks Matt. That makes sense. It is just frustrating because I know the bike should be able to brake harder but I just don't have the confidence when the bike feels like this. I test rode a demo 2010 R6 and I could brake so, so much harder and later. The R6 suspension do feel a lot softer than my R1. The spring rate for the R6, however, is 0.92 kg/mm which is the same as my R1.

To reply to Barry: I'm in the Intermediate group. I'm 135 lbs without gear. I can throw the bike side-to-side with moderate effort (it's not as easy as a 600). I think I'm smooth on the brakes (I normally gradually brake and not grab onto the brakes). The fishtailing happens when I'm slowing down from a fast straight (like turn 1 at Main or turn 1 at VIR South). At Main, I feel the bike fishtail at turn 5 but not as bad as turn 1. I have not had anyone followed me and told me my bike was fishtailing.
 
jcurtis

jcurtis

Control Rider
N2
This would happen to me occasionally on my 600. It happened at times when I was not smooth. Dumping the clutch without blipping would do it. Now that I have a slipper clutch it rarely happens, and it is subtle. I actually kind of miss the rear end wagging.
 
gkotlin

gkotlin

New Member
When was the last time you inspected steering stem bearings and swing arm bearings? When did you last have the suspension refreshed?
 
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tomngle

New Member
I checked and repacked grease swing arm bearings a month ago ( it was still in good condition). I have not checked the steering stem bearings. The forks were refreshed mid season and I had just serviced the rear shock this week for the first time. Last season, however, was my first time on the track with the R1.
 
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tomngle

New Member
I agree. Thanks everyone for the tips. I have a couple of things I could try now: first thing first is the correct spring for my weight. Now I just have to wait 4 months for the first track day.
 
Matt

Matt

New Member
sobottka;164246 wrote: start with the basics- springs and sag. untill you do this, you'll likely chase your own tail
Click to expand...

Rob's spot on.

setting up a bikes handling is like pyramid. you need the base before you can move up to the next item to tune.


Starts with tires, then gearing, then springs, then geometry, then damping. There's no point playing with the next level if you don't have a more basic and important item in good order. Get your springs swapped,
 
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