Rear Wheel Chatter/Heavy Braking

SeñorJack

El Guapo
So I went to some other forums to answer this, then I realized, its not here, so lets put it here!

Here is my question: What is the best way to avoid rear wheel chatter while entering hot into a turn under heavy braking and/or downshifting? And can any of the more experienced members tell us what to do when this happens?

I have a video right now, but its like 2.5gb and I dont know how to compress it. hopefully by the end of the day I can post a gopro vid of exactly what I am talking about.
 

Satan666

Member
Hippity-Hop

So I went to some other forums to answer this, then I realized, its not here, so lets put it here!

Here is my question: What is the best way to avoid rear wheel chatter while entering hot into a turn under heavy braking and/or downshifting? And can any of the more experienced members tell us what to do when this happens?

I have a video right now, but its like 2.5gb and I dont know how to compress it. hopefully by the end of the day I can post a gopro vid of exactly what I am talking about.

Under heavy braking, two major elements cause the chatter.

First, the weight normally on the rear wheel is transferred to the front. Second. the throttle-off engine acts as a compression brake. The rear tire unloads and slows relative to ground speed. As it makes contact with the ground, it tries to speed up the engine back to ground speed. This causes a temporary skid as the engine catches up. If the engine is in a high gear relative to road speed, it is not turning fast enough to maintain combustion (below idle speed) and it begins to misfire.

This condition can be exacerbated by a loose chain and/or a cheap shock absorber which causes a hop from road undulations. Since there is also a rotational element from the fully compressed front spring hitting the bump first, the frequency of the chatter will decrease with speed.

The problem is made worse during the downshift (especially multiple gears) as the clutch is released and the engine speed in the lower gear does not match road/wheel speed. The first suggestion is do not use the engine as a brake during the downshift. Match the rev's to meet road speed and gradually reduce throttle.

There are a couple of common replacements which help the problem.

First replace your rear shock with a better one. I make an adapter for the R1 shock (currently out until mid April) which helps for less than $200. Penske, Ohlin and others make aftermarket shocks. Expect to pay a significant percentage of the value of the bike to go that route.

Second, most 'R' series motorcycles have a slipper clutch which reduces engine braking in gear transitions. That also is going to be a fairly expensive proposition on the FZ8.

Third, take an advanced rider/racer training course. If nothing else, you will get some up close advice on riding technique from those who have BTDT.
 
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SeñorJack

El Guapo
Thanks for the info! I am saving to get ready for a track day so I will take at let a few training courses this summer! thanks again, i have been teying to be smoother with downshifting and my roll off. pnce i outride my stock shock i know where to go!
 

DLSGAP

New member
You can "blip" the throttle on downshift to match engine and wheel speed, this will help... Personally, I like it sliding a little bit... Pisses my girlfriend off though when I back it in lol

Sent from my S3 using Tapatalk
 

subxero

New member
like others have said can be combination of a few things

low quality rear shock in combination with incorrect settings for weight and ride style can be a major cause of chatter

getting your brake, down shifting done in a quick timely manor while keeping your revs stable is the other.

A good blip for rev matching on a down shift can take a while to master, practice practice, practice, but keep it safe, not something you should probably be working on during a spirited canyon ride as if you make a mistake while entering a turn hot it could easily lock up the rear and result in a crash. Practicing blips with down shifts when coming to stop signs ect while the bike is straight up is a little safer but track is ideal but not always an option for everyone.

Riding the clutch a little on the way out as a way of engine braking rev matching is acceptable, is it the fastest, best way, probably not but I am not a motoGP racer so who cares? I know a few very quick riders that ride the clutch out while down shifting, this also keeps the suspension more happy and stable and works like a progressive release of the front brake when done right.

Try a few different things, you will get it sooner or later
 

master paper clip

New member
100% work on your rev matching... makes all the difference when Your attacking the turns, I easily doubled my pace threw turns on my bike just because I'm now able to keep the bike composed under braking into corners just because I learned to rev match properly.... a skill every rider should master
 

NoNine4me

New member
So I went to some other forums to answer this, then I realized, its not here, so lets put it here!

Here is my question: What is the best way to avoid rear wheel chatter while entering hot into a turn under heavy braking and/or downshifting? And can any of the more experienced members tell us what to do when this happens?

I have a video right now, but its like 2.5gb and I dont know how to compress it. hopefully by the end of the day I can post a gopro vid of exactly what I am talking about.
You are using too much rear brake and the wheel is "hopping". You just need to learn to control it. Don't downshift in the turn if you are. Get your shifting done smoothly before the turn. This eliminates the idea that it's somehow associated with "blipping" the throttle or matching engine speed. That has nothing to do with it UNLESS you are doing some sloppy shifting mid-turn and also, either way, shifting and braking are two different things. You can pull in the clutch and coast through a turn and get the rear wheel to hop if you overbrake (I DON'T SUGGEST TRYING THIS) so forget blipping and shifting.

Get your shifting done first and just ease on the rear brake. You are stomping on it. Also maybe you should not be entering the turn so "hot" but go in at a speed where you have some control.

Try a riding school like Reg Pridmore or Keith Code. Or you can keep experimenting by trial and error but either way be careful.:D
 

subxero

New member
^ i don't think that this is quite accurate, i think he is primarily talking about before he is in the turn, i could be wrong though, i guess original post is not overly clear.

It sounds like he is not matching revs close enough when down shifting before and just as he enters the turn. The jump to high revs by poor rev matching causes engine braking to be abrupt and in turn cause the rear to lock up and "chatter".

your down shifting and braking should be done symultaniously along with a handful of other things before you enter the turn
 
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NoNine4me

New member
We all have the same bike. Unless there is something wrong with the OP's motorcycle he just needs to get better control of the motorcycle. In the end all the specifics about whether it is entering the turn, or mid-turn, or whatever don't matter. A good, smooth rider just doesn't have these issues and it takes time and practice to get there.

Dirt riding teaches us this early, about rear brake chatter, but pavement is less forgiving and doesn't allow for much feedback from the bike, a lot of times it feels like "all or nothing" and oftentimes it is.

This is a skill/experience issue, pure and simple, regardless of particulars. I suggest -- as would Keith, Reggie, or Freddie -- practice in an area where you won't put anyone in danger and gradually creep up on your skill limits. Don't get sucked into trying to be an "A" group rider when you need to really start out in the "B" group.

As a former track instructor I do know of what I speak and I was just thinking earlier today of a hotheaded young lady who ran off the track her first time out. She just wouldn't listen and later on that year, she crashed pretty bad and got busted up.

Motorcycles can and do get us hurt, it's your choice to be smart about it or charge in. Charging in don't work, trust me!
 
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