No, just end to end of spring.
F: Frame Help required measuring coil lengths on AVO coil over rear dampers.
- Thread starter timetraveller
- Start date
I am sure it's been said before,
There is a train of thought, You can use a weaker spring with More heavy damping.
There is a train of thought, You can use a weaker spring with More heavy damping.
Using up 2/3 of the available travel just me sitting on the bike is a bit too weak, which is what I have with the 275 lb spring and no preload so imagine carrying a pillion.
I prefer a stronger spring and less damping which is what I have on the front, 45lb springs, 11mm packers and the AVO damper on the first click and it rides beautifully, but then I weigh 21st
Bill, what we found with the front of the bikes when I started supplying the JE steering stems was that once we did the Greg Brillus mod of fitting ball races to the rear of the lower link then even the highest level of damping built into the standard AVO dampers was inadequate. The reduction in friction is remarkable. Chris Launders who was doing the test riding, is a heavy chap and it was so bad that he thought that the damper had failed. In the end AVO made special dampers with increased damping and I now supply these to any heavy riders. Heavy in this context means about 18 stones or above. These are too stiff for lower weight riders and so there is a limit to what can be done with the damping and still have comfort. As Chris has just posted (while I was writing this) the damping is not going to compensate for too much weight. Apart from data points taken from Chris' bike the only other one has come from MVH and that is just one point to help to check if the table of figures we have produced is correct. The amount of compression measured by MVH only differs from my calculated one by 0.2" which sounds to be not too bad. But consider that a fifth of an inch with a 350 lbs/inch spring is 70 lbs so I woiuld still like to get some more measurements to check/improve my table. I know that there are quite a lot of you out there with the AVO rear coil over dampers as I have supplied many of them. Any chance of any more feedback?
Chris, when you get off your bike does the front end go to a "Topped out" condition.....?...... You have your front end set up about exactly how i'd recon it should be........ Just a couple of tips, not wanting to change the topic too much........ I weigh around 75 Kg's, and I've just recently changed over one of my front springs to one of Norman's 36 lb/in pretty much at it's full length ( that is, un-cut) this has softened the ride on my bike considerably.........We also did the exact same mod to my mates 600 Comet but we did cut about 15 mm off one end.........He told me not long ago that his Comet is the best it has ever been, and this was long after we initially installed the modified front end. From my experience the front end does not like a stiff shock absorber at all........So much so that i have had Ikon produce a special batch of re-valved shockers to my specs........The first testing of these was a slow process on acount of the company being so busy, covid, and so on........I have 3 new ones that should arrive any day now, and i will order small batches as I feel will be needed.......Just quickly getting back to the AVO coilover........The one I had hear, the threaded adjuster ring for the pre load (alloy) suffered a total failure of the ACME thread........ My advice to anyone adjusting one, would be to spray some Inox, CRC or light oil on the thread and the faces of the ends of the spring, and to lightly jack the middle of the bike to unload the shocker as much as possible before winding up any pre load........ I was lucky I didn't lose the end of my finger when it went on me. Finally.......My Dear Norman......You are going to hate me for this.........I have continued interest here for the stem kits, and would need no less than 6.......It is very possible that after my next big rally down in Tasmania this comming March, i may very well need more........So if you have had any others interested, then this could boost the numbers........Many thanks and cheers for now.......... Greg.
That's OK Greg. I already have three people chasing me for more JE stems so with your six that make it worth while getting ten made. That is the minimum quantity the CNC guys will make. Things are slow with them at the moment. I have been waiting for five months for some H13 ss to be made. I don't think it is covid related, just too much work with their big projects. My orders are in the few thousands of GB pounds. Some of their stuff must be hundreds of thousands upwards so I just have to be parient.
By the way, it is interesting that you are now finding that softer springing at the front can be an improvement. That is what we have found over here.
By the way, it is interesting that you are now finding that softer springing at the front can be an improvement. That is what we have found over here.
Thanks Norman........The springs are not too bad to set up.......It is very important to make sure there is no friction in the front.......Especially in the spring cases, as these can jam up quite readily if they still have old grease/muck in them, but moreso if the outer cases are damaged.......These will bind quite badly. I have done exhaustive testing on shock absorbers on the front........It appears to me that the Girder type forks, as per the Bramptons do not actually need much damping.......perhaps more if less friction exists, but there are still many bushes and spindles that cause this...........The needle rollers I did to the front end of my twin racer was probabaly as close to nil friction in these forks as you could get.........but the cost and trouble is not worth it. The issue of slowness in getting machining done must be a world wide problem........last year was very difficult for me in getting things like this done........ It became quite stressful at times........Cheers.
Considering Greg's experience with the spring adjusting nut, would it be a good idea to double this nut up?
Hi Greg
No mine doesn't top out, I had 1/4" initial sag and a further 1/4" when I sat on it, though it may have sagged further now with use. The thing with the Bramptons could be the springs being barrel wound offering a variable rate.
No mine doesn't top out, I had 1/4" initial sag and a further 1/4" when I sat on it, though it may have sagged further now with use. The thing with the Bramptons could be the springs being barrel wound offering a variable rate.
Several years ago I did some measurements using bathroom scales and my small milling machine to apply known amounts of compression to the rear suspension springs on B/C Vincents. When I plotted the graphs they seemed to be linear despite the fact that they are slightly barrel shaped. Not as much as Bramptons springs but definitely not cylindrcal coils.
