# Rear suspension adjustment?



## Salad Dodger (20 Dec 2009)

My bike is a Decathlon Rockrider 6.3 full suspension.

Please can anyone help me with some advice about adjusting the rear suspension?

It has an oil filled rear shock, with a coil spring over the top of it.

The spring has a collar on one end, which holds the top end of the spring in place, and the collar can be wound in and out on a screw thread by about 2 inches, to presumably add or take off pre-load to the spring. Hope you understand what I mean....

I have not adjusted the rear suspension at all, so far. At present the pre-load is set at about one third of the way down it's screw thread. So my questions are:

1) Am I right in thinking that if I adjust the collar and compress the spring more I am adding more pre-load, so the rear suspension will not "give" so easily? And if I adjust the collar the other way, to let the spring extend more, I am in effect softening the suspension?

2) My bike is an XL sized frame, but I guess that at about 17 stone I am still towards the upper end of the intended weight for the frame, and for the suspension. So should I be thinking in terms of adding more pre-load to the spring? Will this reduce the tendency of the rear to "bounce" whilst pedalling up hill. (I know this is a cheap bike, and that without a lockout for the rear end it will still have a degree of bounce anyway, but would adding more pre-load reduce, but not eliminate, rear end bounce)?

Sorry to go on so, but before I start playing about with the bike I would welcome any guidance that the more experienced of you can offer....


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## marzjennings (21 Dec 2009)

You may want to check the spring rating as well. Yes you can screw down the cap on the spring, compress it some more and add some pre-load, but you'll also be affecting the travel characteristics of the shock, reducing travel in the suspension and making it harsh. 

You may be able to switch the spring out for a higher rated spring. At 16stone I switched out a 400lbs spring for a 700lbs spring on my Fox shock which really improved the ride.


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## Salad Dodger (21 Dec 2009)

Thank you.


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## lukesdad (21 Dec 2009)

Dont get preload/spring rating/spring length confused with damping (bump & rebound).

The spring length/ rating/ preload determines the length of travel and ride height of the frame in relation to your rear wheel and to acertain extent the speed of travel depending on the characteristics of the spring.

The bump & rebound determines the speed that the spring will be allowed to move fast or slow. (you should have an adjustment screw for this on the main body of the shock maybe 2 one for bump and one for rebound. If you dont there s not much you can do other than change the oil.)

Changing the spring rating will change the characteristics of your suspension more than adding preload to your exsisting spring. As the shock and its damping would have been designed to work within certain spring ratings.

To answer your question you would need to add preload to your exsisting spring (a little at atime amazing what afew turns will do) and slow down your damping which restricts oil flow through the valves to the chambers. By either adjusting your damping screws or replacing with a thicker sus. oil.

Remember though too much adjustment may be detremental to the way the bike handles in other areas i.e over the rough stuff .

Its not as straight forward as you may think. Hope this helps.


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## Salad Dodger (22 Dec 2009)

Thanks lukesdad. As I know less than nothing about the theory of how suspension is supposed to work, I am grateful for all advice.


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## 02GF74 (31 Dec 2009)

best way is to ride over the same terrain and adjust the settings.

suspension is a compromise - there will be settings that work better on some terrain e.g. steps but not so well on say little lumps, and vice veresa.

I have settings about 1/2 way and set them to max and min and cannot say that I notice all that much difference to make mw sit up and say WOW!!!


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## lukesdad (31 Dec 2009)

Before changing anything 2 further points to consider:Firstly if the unit has no damping control (bump & rebound) bobbing will always be a problem.

Secondly make sure you have the Sag set properly. Sag is the amount the suspension compresses once your weight is on the bike. A recomended figure is 30% of total sus. travel i.e the unloaded weight to the sus. bottoming out this is wheel travel not spring compression. I like mine less than this as I prefer a harder ride.


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## lukesdad (31 Dec 2009)

02GF74 said:


> best way is to ride over the same terrain and adjust the settings.
> 
> suspension is a compromise - there will be settings that work better on some terrain e.g. steps but not so well on say little lumps, and vice veresa.
> 
> I have settings about 1/2 way and set them to max and min and cannot say that I notice all that much difference to make mw sit up and say WOW!!!



This is why alot of xc racers prefer a hardtail. I only use my full susser for recreation.


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## 02GF74 (1 Jan 2010)

lukesdad said:


> This is why alot of xc racers prefer a hardtail. I only use my full susser for recreation.




hmmm, but then full suspension bikes weigh more than hardtails - that has gotta have something to do with it too??

anyways, I am putting on my thermals and going out, just need to decide which bike ......


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## lukesdad (1 Jan 2010)

02GF74 said:


> hmmm, but then full suspension bikes weigh more than hardtails - that has gotta have something to do with it too??
> 
> anyways, I am putting on my thermals and going out, just need to decide which bike ......



For sure,its another factor.


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## 02GF74 (5 Jan 2010)

02GF74 said:


> anyways, I am putting on my thermals and going out, just need to decide which bike ......




and I did too - got in about 7 miles - quite please that even with the post Christmas ballooning, was still able to get up the steep hills.


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## 02GF74 (5 Jan 2010)

02GF74 said:


> anyways, I am putting on my thermals and going out, just need to decide which bike ......




and I did too - got in about 7 miles - quite please that even with the post Christmas ballooning, was still able to get up the steep hills.


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## lukesdad (5 Jan 2010)

lukesdad said:


> For sure,its another factor.



As is loss of power/energy due to the working of the supension.


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## lukesdad (5 Jan 2010)

lukesdad said:


> For sure,its another factor.



As is loss of power/energy due to the working of the supension.


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