185x55 shock on a 190x45 frame possible?

[Jerry]

I have a technical question:

Does it cause problems or will te riding quality/behavior (seriously) influenced when you mount a 185x55 size shock on a fully frame that is actually intended for a 190x45 shock? The difference is only 5 mm after all (in the natural suspension direction). 

If yes and 5mm is too big a difference, can this difference be reduced through so-called offset bushings? Theoretically, the difference between eye-to-eye of the shock can be reduced to just 1 mm with this bushings, namely. Or do I see all of this wrong?

Hopefully, some of you know the redeeming answer. Thanks in advance.

[sclyde2]

At bottom out, the difference is 15mm, 145mm vs 130mm.  That is significant.  You are likely to have issues, such as a tyre hitting the seattube or a seatstay crossbrace (if there is one) hitting the seattube at bottom out.  Put a wheel on the (shock-less) frame, push it down until frame contact occurs, the measure the distance between the shock mounts (centre to centre).  That'll tell you if it'll work or not.  Note that some shocks can have their stroke reduced.

As for the other end of the travel (at top out and at sag), that 5mm will translate to a back end that sits 10-15mm lower than what the bike is designed for, maybe a bit lower once the extra sag of the longer stroke shock is factored in.  If you are looking for a lower BB and slacker head and seat tube angles, maybe this is your intention.  I wouldnt do it for any other reason.

[mixlax]

If it fits, this could drastically change the bikes geometry in an interesting way, especially paired with a longer fork to slacken it even more and raise the BB. I would not buy parts to do this test, but if I had them, it would be fun to have mounted just to see how the bike handles...

[Jerry]

Thank you for the feedback.

Something in me says to follow the advice of sclycle2 and not to start with it. The other half is just as curious as mixlax. 

[sclyde2]

I'm not saying don't do it - just saying to check the clearances , and be aware of the geo changes before you do.  I did something similar on an old frame to make it slacker.

[ChinaCruz]

You might be able to stack bottom out spacers in the shock and make it a 185x45. Then it would be only 5mm deeper in the travel.