Changing shock size. What's advantages/disadvantages?

Forum rules
Please can you post items for sale or wanted in the correct For Sale section. Items / bikes for sale here will be removed without warning. Reasons for this are in the FAQ. Thanks
Post Reply
PARUS
Senior Member
Posts: 1160
Joined: Tue Apr 29, 2008 10:01 pm
Bike owned: Already 20% of NC29...
Location: Seattle, USA
Contact:

Changing shock size. What's advantages/disadvantages?

Post by PARUS » Tue Feb 24, 2009 10:59 pm

Hi,

I just thinking to play with shock size. Sorry due to lack of english I tried to show all my thinking in picture. Please, correct me if I'm wrong...

Image


PS: There is no my bike. Sorry....

squirrel_hunter
Settled in member
Posts: 164
Joined: Tue Apr 29, 2008 8:59 pm
Location: Sunny Swindon

Re: Changing shock size. What's advantages/disadvantages?

Post by squirrel_hunter » Wed Feb 25, 2009 12:15 am

I'm not an expert but...

From my understanding points 1 + 2 are correct. If you raise the rear ride height you will effect the geometry (rake and trail) which will result in a faster turning, but reduced stability in a straight line. By how much depends on the difference in length of the shock that you are using. When I started playing around with my bikes suspension I took a look at some of the work that Tony Foale has done. Very interesting, worth a read and the programs to calculate rake and trail etc are useful as this is what you are altering.

As for point 3 you are incorrect. The firmness of the suspension is controlled by the stiffness of the spring, the damping rates (compression and rebound) and the pre load settings. Altering any of these will make the ride more or less hard. But I'm not a setup expert.

PARUS
Senior Member
Posts: 1160
Joined: Tue Apr 29, 2008 10:01 pm
Bike owned: Already 20% of NC29...
Location: Seattle, USA
Contact:

Re: Changing shock size. What's advantages/disadvantages?

Post by PARUS » Thu Feb 26, 2009 12:05 pm

squirrel_hunter wrote:I'm not an expert but...

From my understanding points 1 + 2 are correct. If you raise the rear ride height you will effect the geometry (rake and trail) which will result in a faster turning, but reduced stability in a straight line. By how much depends on the difference in length of the shock that you are using. When I started playing around with my bikes suspension I took a look at some of the work that Tony Foale has done. Very interesting, worth a read and the programs to calculate rake and trail etc are useful as this is what you are altering.

As for point 3 you are incorrect. The firmness of the suspension is controlled by the stiffness of the spring, the damping rates (compression and rebound) and the pre load settings. Altering any of these will make the ride more or less hard. But I'm not a setup expert.
How much reasonable changes shock size? I have checked and shock with size 310mm or maybe more will fit.

squirrel_hunter
Settled in member
Posts: 164
Joined: Tue Apr 29, 2008 8:59 pm
Location: Sunny Swindon

Re: Changing shock size. What's advantages/disadvantages?

Post by squirrel_hunter » Thu Feb 26, 2009 8:38 pm

It really depends on what you want to gain from doing this?

If its quicker turning then drop the forks through the yokes, there should be some information here on what is considered the best amount.

PARUS
Senior Member
Posts: 1160
Joined: Tue Apr 29, 2008 10:01 pm
Bike owned: Already 20% of NC29...
Location: Seattle, USA
Contact:

Re: Changing shock size. What's advantages/disadvantages?

Post by PARUS » Fri Feb 27, 2009 11:47 pm

Found following about suspension set-up.

http://www.gostar-racing.com/club/motor ... set-up.htm
Last edited by PARUS on Mon Mar 02, 2009 10:06 am, edited 1 time in total.

yeurman
Settled in member
Posts: 157
Joined: Sat May 24, 2008 9:47 pm

Re: Changing shock size. What's advantages/disadvantages?

Post by yeurman » Sun Mar 01, 2009 10:10 pm

I run my bikes on different geometry, . wheel base is 135 mm on dry bike and 162mm on wet bike, with the dry bike having a 150mm spring and the wet 170mm spring. would be rude for me to give any more details... hope this helps. Col (NC29)

PARUS
Senior Member
Posts: 1160
Joined: Tue Apr 29, 2008 10:01 pm
Bike owned: Already 20% of NC29...
Location: Seattle, USA
Contact:

Re: Changing shock size. What's advantages/disadvantages?

Post by PARUS » Mon Mar 02, 2009 11:21 am

yeurman wrote:I run my bikes on different geometry, . wheel base is 135 mm on dry bike and 162mm on wet bike, with the dry bike having a 150mm spring and the wet 170mm spring. would be rude for me to give any more details... hope this helps. Col (NC29)

Thank you mate.. will check this on mine soon..

PARUS
Senior Member
Posts: 1160
Joined: Tue Apr 29, 2008 10:01 pm
Bike owned: Already 20% of NC29...
Location: Seattle, USA
Contact:

Re: Changing shock size. What's advantages/disadvantages?

Post by PARUS » Tue Mar 03, 2009 6:02 pm

yeurman wrote:I run my bikes on different geometry, . wheel base is 135 mm on dry bike and 162mm on wet bike, with the dry bike having a 150mm spring and the wet 170mm spring. would be rude for me to give any more details... hope this helps. Col (NC29)
Did you change wheel base just changing shock size? Correct ?

PARUS
Senior Member
Posts: 1160
Joined: Tue Apr 29, 2008 10:01 pm
Bike owned: Already 20% of NC29...
Location: Seattle, USA
Contact:

Re: Changing shock size. What's advantages/disadvantages?

Post by PARUS » Tue Mar 10, 2009 10:47 am

yeurman wrote:I run my bikes on different geometry, . wheel base is 135 mm on dry bike and 162mm on wet bike, with the dry bike having a 150mm spring and the wet 170mm spring. would be rude for me to give any more details... hope this helps. Col (NC29)

I have changed wheel base little bit with help shock height adjustment.

Image

Post Reply