W/C fork lengths

[Teckhardt]

I have looked but can't seem to find the differences in length of forks between Scrambler and the other models of wide case. Was the 35mm Marzocchi the norm for all of them? Seem to recall that one model (maybe more) had Ceriani forks.

Suspension tuning is a bit of a black art to me so if you start going into rake and trail and blah blah, my eyes may start to gloss over.

What is the best length / version to use for a road frame? Any non-standard forks (ie from another make/model) that would work?

[Jordan]

SCR models have longer forks than road models. You can put shorter forks on the SCR, but the rear suspension mounts are also different (mounted lower on the frame), and because the suspension units are similar length, it will affect the attitude of the bike, and has some effect on steering geometry. The longer SCR forks match the rear suspension height. Note the centre stand is also longer on SCRs.
The best forks to put on a single with a standard road frame, like a Mk3, I think would be the late 35mm types with internal springs. I think Ducati had both Ceriani and Marzhochhi 35mm forks of similar design fitted to the singles? These are shorter than SCR forks. The last models have triple clamps, usually painted black, that give more trail which gives a more stable feel than earlier ones that have more offset. SCR also have internal springs and are 35mm tubed, when the road models had smaller tubes and external main springs. I've put RD 350 Yamaha tubes in SCR forks, not ideal but they worked OK. You could fit the Yamaha or other brand forks to the triple clamps, if the tube diameter is the same. SCR has lips on the top triple clamp that the fork tubes butt up against - they could interfere with non-standard tubes but you can work around this. The road bikes don't have that feature, so are easier to adapt. Or, the whole fork assembly including triple clamps from another bike could be fitted, if you make the bearing adaptors to suit the frame - not so easy on most Ducati singles because of the "bicycle" type steering bearings, but it can be done.
My current 350 has a SCR frame and shorter forks from a silver shotgun. It looks OK, but the shorter length must have an effect on dynamics. I blame that on my spill, after I hit a very small pothole - it threw me off. For confidence, I've fitted an hydraulic steering damper and didn't get into trouble again.
To keep the original suspension geometry on your bike you could use the standard long SCR forks.
If you want to alter the standard arrangement safely, you might not be able to avoid some study of steering geometry!

[Eldert]

according to the Amici dello Scrambler website the series 1 scrambler stancions are 57.4 cm and series 2 are 60 cm long
but whem you take the forks apart and measure the damping rods you wil see that scrambler rods are 2 cm longer
them Mark III rods . the bottom sliders are also longer . so Scrambler forks have 2 cm more travel

RT forks have even more travel . the damper rods are 4 cm longer then a Mark III and 2 centimeters then a Scrambler rod
and then there are the rim sizes 18 , 19 and 21 on a RT . you have to take al of this in account

the only Ducati that had Ceriani forks is the disc brake Yellow Desmo . now this bike steers very well .
why is this ?? its al in the offset of the tripple clamps . most Ducati singles with 35 mm forks have tripple clamps
with 60 mm offset . the Ceriani disc setup has less . i dont have a set laying around to measure

dont make the mistake of fitting a set of Ceriani GP tripple clamps , these have 70 mm offset .
i had a real tankslapper with one of these sets and believe me it was scary

by fitting a tripple clamp with less offset you increase trail and that is what you need
on our racing single we went to a Dunlop KR 825 front tire . this tire is 11 mm lower then the tire we used before .
the bike was just not feeling right anymore . after doing some math we found out we lost 6 mm off trail .
we fixed the problem by fitting tripple clamps with 50 mm offset

if any of you wanne read up on this subject it is in John Bradleys book the racing motorcycle volume 1

Eldert