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steve_xland
22nd November 2010, 15:10
I'm getting a little bit of the 'death wobbles' when riding over hard pack bumps. Handle bars just go from side to side on their own which can freak you out if you aren't ready for it.
I'm wondering whether hardening up the dampers will help to dial this out.

Honda136
22nd November 2010, 15:28
I'm getting a little bit of the 'death wobbles' when riding over hard pack bumps. Handle bars just go from side to side on their own which can freak you out if you aren't ready for it.
I'm wondering whether hardening up the dampers will help to dial this out.


The knowledge I have of suspension is limited but will offer my help...


Depending on how much of the suspension stroke is being used will indicate what to do about it; i.e. if you're using too much of the stroke, it is obvious that you should add compression (+) because the lack of preload means that it is using too much of the stoke. But if you are only using a little bit it will feel rough in the front as you are using too little of the stoke, meaning that you should soften it off (-).


If that still does not fix it then try playing with the rebound clickers. Adding rebound dampening will slow the rate at which it returns (+) and taking the rebound clickers away (-) will mean it comes back faster. I find that when I have too little rebound dampening it is all over the place..


Daniel.

Rupe
22nd November 2010, 17:41
I'm getting a little bit of the 'death wobbles' when riding over hard pack bumps. Handle bars just go from side to side on their own which can freak you out if you aren't ready for it.
I'm wondering whether hardening up the dampers will help to dial this out.

Put all your clickers to standard settings. Go somewhere like kimmies and ride the motox track or first part of enduro loop, and work on your rebound first. Go two clicks at a time. One way will make the front end feel lighter, softer, and more twitchy. The other will make it firmer, stable and may give you arm pump. Find the right balance for you then adjust the compresion to suit...just do the rebound first.

If you take your time a do it properly you will leran what adjustments help for different terrian, rather than someone guessing to fix your problem.

Danger
23rd November 2010, 06:25
There are many causes for head shake such as steep fork rake or not enough trail, whats your rider sag at?
Is the head shake on acceleration or de acceleration?
Is the chassis straight or is the chain adjuster off creating misalignment of the wheels?
Too much rebound damping.
Not enough low speed compression damping.
Too much high speed compression damping.
Too high tire pressure.
Poor tire compound or type (Shinko's are great in sand but have very stiff side walls and I've seen them cause head shake on hard surfaces).
Tire not mounted correctly or damaged, wheel out of balance.
Brake rotor bent.
Worn out or loose steering bearings.
Anything that makes the front end lower than the rear.
Death grip.
Anything that makes the forks sticky. Check your lower triple clamp torques and make sure your axle is centered. Align the tubes.
Get a lot of those KYB's that have the annodising worn off the inside of the tubes causing sticky forks.
Air pump in the forks.
Bushings damaged from slide hammering apart.
Metal embeded in the bushes.
Steel spring spacer directly on aluminium cap.
Spring guide rubbing on ID of spring because of use of solvents growing the guide.
Fork spring to large an ID.

Hope that gives you some things to try.

wingman7nz
23rd November 2010, 09:50
i found that having my bars rolled too far fwd caused head shake when standing over braking bumps. some people have their bars rolled quite far fwd and dont get issues however i am running 30mm risers so that might have had something to do with it causing bad offset against the rake or sumthin.. just my 2 cents :blink:

Scotty Dog
23rd November 2010, 21:33
Hi mate
as stated above, many things it could be. If its an older bike its probably a combination of a few things. Probably needs a GOOD service to start.
Simple checks are. Check the rider sag, wants to be about 100mm rider sag, or around 20mm free sag.
Your forks want to be sitting no further than 5mm up through the clamps.
check your fork compression adjuster (bottom of fork) isnt fully open. Set to about 8 click out from full in. Rebound on top of fork wants to be on 12 out.
good luck, its good fun making stuff better