OK I will do that but I need to explain what is going on here. Not all spring boxes are such a good fit that this will be a problem but if they are a nice tight sliding fit of the inner in the outer and a thick grease is used then it might be necessary. Secondly I need to explain what 2x4 is doing fitting a small diameter spring inside the outer spring. Those of you with many years of experience will recall that Vincents fitted inner and outer springs into the front spring boxes. That way both singles and twins could be catered for without having to have alternative springs made. In addition, if a heavy sidecar was fitted and the ingenious girdraulic design did not provide sufficient front support there was a ready made additional change which could be used. A few years ago I was having a discussion with Robin Stafford, who is one of the chaps who works at the Spares company, about his experience with the JE system which he had fitted to his twin. He was using 36 lbs/inch springs, which is what I would normally recommend for a twin with a mid weight rider. He found that occasionally over the worst potholes it would bottom out. Making the damper stiffer or fitting stronger springs would have probably prevented the bottoming out but would then have made the ride harsher and less compliant over smaller bumps and he liked the way the bike behaved on normal roads, One alternative would have been to get multi rate springs made but I suggested that an alternative could be tried. That was to fit shortened inner springs inside the new spring supplied but to shorten them to the extent that they would not come into play until about one and a half inches of travel/compression had been used. Note that the JE system allows up to about 3.5" of total wheel movement. The figures for the 30, 33 and 36 lbs/inch springs are full spring length is 16.5". Installed length 13.5" (giving 3" of pre-load and then a total further compression of 3" to 3.5" for suspension travel. The idea was that inner springs with a length of 12" would allow the outer springs to move by 1.5" before they came into play after which the effective combined spring rate would be about the original 30. 33 or 36 lbs/inch plus about 10 lbs/inch. Robin tried this and found that it suited his riding style and weight very well. He has a nice easy ride over the smaller bumps but then does not bottom out on the major potholes.
So far as I know Robin is the only chap to have tried this but 2X4 is trying it for himself. I would note that most people find one of the four different springs which I can supply with the JE system adequate. That does not mean that it cannot be improved on and only the rider themselves can decide whether they can live with what they have or would like to try to improve it. The inner springs are listed as FF13 and in stock at the Spares Company, about £30 for the pair.
