A note about “short” and “long” versions of AVO rear dampers and coil-overs.
When I developed the first AVO rear damper in 2012, my primary objective was the shortest possible closed length, but combined with a long stroke. This is why the rear mounting is offset.
The purpose of this short closed length was twofold.
The first was to make the best possible use of the short standard springs. When the shortness of the standard spring results in much less than 1” of bump travel, even a ¼” gain is valuable.
The second was a low saddle height.
However, I recognised that if this short damper was fitted to a bike that had been converted to a fully sprung seat, it became quite likely the mudguard would hit the seat at full bump on many bikes. As there is so much variation between bikes, the only way to be sure is fit the damper only, lift the wheel and see what happens.
So we produced a second “long” version of the rear damper that had a similar closed length to the original Vincent damper and would be a “safe” choice for everyone.
Four years on the situation is a little different. The benefit of the extra short damper is diminished by using different springs. The remaining benefit of a 3/8” lower seat is unimportant to many riders, or at least does not justify modifying the seat/mudguard clearance. Lastly, the different combinations of specifications required AVO to frequently make-to-order, which is inefficient because of set-up times.
For these reasons, the “short” rear dampers will be discontinued when existing stocks are exhausted.
HOWEVER, as a favour to me, AVO have produced just one batch of “short” coil-over units.
They will not be advertised, but if like me you have weak and wobbly legs and appreciate even a slightly lower seat, you can order a short version of the coil-over or a short version of the new “ready to-fit” rear damper, while stocks last. Same prices!
There are two caveats:
1) You will have to decide for yourself if a short unit will fit your bike without seat/mudguard clearance problems. See info below. To the best of my knowledge, there will not be any problems with the original semi sprung seat set up. But if you have (or may) convert to a fully sprung seat, problems are fairly likely. I lowered my mudguard, but you may not want to go to this much trouble.
2) The “long” version of the coil over has a very convenient facility that it is just possible to change the spring without a spring compressor. With the “short” coil-over, a spring compressor is definitely required.
Info you may find useful:
Standard Vincent damper closed length 7.188”
“Long” AVO coil-over or damper closed length 7.195”
“Short” AVO coil-over or damper closed length 6.96”
These AVO closed lengths are calculated by estimating that in the worse case the suspension will come to a halt when the 20mm rubber bump stop is compressed to a length of 8mm by a force of over 1200lbs. (This is in addition to the spring force of around 800 -1200lbs, so it would need to be a BIG bump with a heavily laden bike.) Bump stop calibration curve available on request!
The minimum length of the Vincent damper is much easier to define, as the hydraulic stop is very short and stiff compared to a rubber bump stop, which provides a much nicer progressive rising rate.
