Author Topic: Forks bottoming out.  (Read 234 times)

0 Members and 1 Guest are viewing this topic.

Offline OldBones

  • Newbie
  • *
  • Topic Author
  • Posts: 6
Forks bottoming out.
on: August 02, 2020, 09:00:21 AM
So I have reworked forks and on track under heavy braking the front is bottoming out with wheel chatter. If I add more preload this will take the sag measurement out. So is it worth sacrificing the sag to make the fork stiffer?


Offline Tomspurs

  • Street Triple God
  • *****
  • Posts: 9359
  • 09 ST, CRF230F, DT175MX, DT175C, PE175Z, IT175J
  • Bike: 09 Hinkley ST
  • City / Town: Wallington
  • Country: england
Re: Forks bottoming out.
Reply #1 on: August 02, 2020, 10:15:23 AM
Wot about heavier oil....but I know nothing about forks...best talk to a suspension company IMO   :027:
Parc Ferme - Car Park Ross

Offline Green_Ninja

  • Street Triple Master
  • ****
  • Posts: 559
  • Bike: Street RS/Street R
  • City / Town: Sale
  • Country: gb
Re: Forks bottoming out.
Reply #2 on: August 02, 2020, 10:29:01 AM
*Originally Posted by Tomspurs [+]
Wot about heavier oil....but I know nothing about forks...best talk to a suspension company IMO   :027:

If the sag is correctly set and the spring rate correct for your weight more compression damping may help so as above heavier weight fork oil could help.

You say the forks have been reworked, how so, and did bottom out before?

Offline Ron1000

  • Street Triple Pro
  • ***
  • Posts: 215
  • Bike: New street 2021
  • City / Town: Livingston
  • Country: gb
Re: Forks bottoming out.
Reply #3 on: August 02, 2020, 11:09:21 AM
Usually a Suspension guy at the tracks these days. Id ask him first then go from there.
Just Because your breathing Doesn't Mean Your Alive

Offline JanM

  • Street Triple Master
  • ****
  • Posts: 350
  • Bike: 08 Striple's
  • City / Town: Hilleroed
  • Country: dk
Re: Forks bottoming out.
Reply #4 on: August 02, 2020, 11:22:23 AM
*Originally Posted by OldBones [+]
So I have reworked forks and on track under heavy braking the front is bottoming out with wheel chatter. If I add more preload this will take the sag measurement out. So is it worth sacrificing the sag to make the fork stiffer?

Add more fork oil (not heavier weight) to increase stiffness of the airspring which will help during braking. Depending on the setup of your reworked forks you need to see how much more oil to add, but remember it is much easier to add than remove, so do not put in too much. Usually add 10 to 20 ml, depending on you current oillevel.

Offline ninja365

  • Street Triple Member
  • **
  • Posts: 48
  • Bike: Street Triple
  • City / Town: Norwich
Re: Forks bottoming out.
Reply #5 on: August 02, 2020, 12:09:20 PM
*Originally Posted by OldBones [+]
So I have reworked forks and on track under heavy braking the front is bottoming out with wheel chatter. If I add more preload this will take the sag measurement out. So is it worth sacrificing the sag to make the fork stiffer?

Hi Oldbones, have same problem as you and lost the front on a track session last week when the forks bottomed out, i only have the standard ST forks (Not an R) and have been seriously thinking about getting them re-worked and modified by MCT Suspension as this was the second time in less than a year i've had a front end get off.

Did you re-work your own forks with heavier springs and new oil?, what did you use?.

I am getting to a point where am seriously thinking of selling and trying a R model than will allow more suspension setup as can't afford another off and the repair costs. Hooning around on the road is perfect for the ST which is why i bought it but for a few track days each year in the inter group its showing limitations with the front suspension. Have thought about transplanting an R front end in but its just not cost effective.


Offline OldBones

  • Newbie
  • *
  • Topic Author
  • Posts: 6
Re: Forks bottoming out.
Reply #6 on: August 02, 2020, 01:05:16 PM
I have 2013 r model and had the forks worked on by a reputable company for my weight and riding and new shock. Never had chatter with the standard forks though I was occasionally bottoming them out. I did have a suspension guy look at them at track and he said they were to soft and added more rebound and damping to the point the front was slow to compress and slow to rebound. It made the bike handle like a bag of ####. So I will add more preload and see what happens the problem is I've wasted two track days messing around. Think I will talk to the guys that worked the forks for some input.