how to measure if a replacement rear shock will fit the frame.

[HaydenWilson]

Hey all.

 

I want to replace the rear shock on my 08 stumpjumper fsr as i keep bottoming the damn thing out and just generally do not like it.

 

Specialized has used a weird shock size 7.25 X 1.75

 

Some internet trawling has said that i can fit a 7.5 X 2.0 or even a 7.875 X 2.5

 

what is the best way of measuring if a shock will fit?

 

I am aware that by changing the eye to eye length i will likely raise the bottom bracket but as i am planning on putting on a longer travel front fork it should not affect handling too much as the longer fork should compensate for the steeper head angle as a result of the raised bottom bracket.

 

any advice?

[Johan Bornman]

Shocks are measured in stroke and extended length.

 

Those look like inch sizes. Translated into civilizees, it becomes a 184mm x 44.5mm.

This is a longish shock with a longish travel.

 

Your internet trawl says you can fit up to a 200mm x 63mm.

 

Put your bike in a stand and remove thel rear wheel and at least one of the shock mounts.

 

Now have someone hold the back triangle for you whilst you guide him/her, using a ruler, up tot he 200mm point. Look for any frame part that bottoms out or hits something else. If nothing comes in the way of that much opening of the rear triangle, you can go ahead.

 

You will have to increase the new shock's travel proportionally to the new length. This realationship may or may not be linear, depending on the path the shock mounting pionts move, but a few measurements with the help of our assistant will tell you the truth.

 

Measure twice, then drink beer.

Edited August 24, 2012 by Johan Bornman

[HaydenWilson]

Measure twice, Drink beer. Sounds like a good plan! thanks man!

 

Dont want to go and order a very expensive shock and then it does not fit!