Do I need a Slipper Clutch for the use I put my bikes to? – No. Have I ever ridden a Slipper Clutch equipped bike? – No. Will I get anywhere any quicker or more efficiently with a Slipper Clutch fitted? – No. Can I justify the cost of a Slipper clutch? – No. Would I know which of my 3 bikes would benefit most from one? – No. Am I intrigued by them and want to fiddle with one? – Absolutely. Do I want to understand them and spend some time learning how to get the best from them? – Yes. Am I likely to enter the world of Slipper Clutch ownership the easy way by buying a complete new one? – No, of course not! Have I brought a knackered incomplete one cheap to play with? – Yes. Have I spent too much time already inspecting it, measuring it, and researching it on the net? – Yes. In the image above the drum looks completely knackered, but actually it’s not that bad and is recoverable. It’s obviously missing some hardware but the basics are there. I’ve had a lot of ‘fun’ fiddling with and understanding what works with normal dry clutches over the years with regard to mods, stack height and plate order etc, so want to push myself on a bit with this. I believe it’s the STM 6 ball type, Ducati Performance Branded, and of the type that would have originally been fitted to the 748R etc as standard. I can use it with standard plates, Basket, and springs, which I have all of, but am going to need some parts. I do have a couple of Brand new Spider Springs, which came in a job lot of parts I brought, and until now didn’t really know what they were for. It looks like there are two versions of securing the drum, spring etc to the shaft. The early version with conventional nut, washer and spacer: And the later version with a special nut: I’m going to go for the later version as I’m ½ convinced the early version has the possibility of clamping the Spider spring so it can’t rotate and contributes to the reports of broken Springs. Oh, and of course I’m aware of the requirement for regular maintenance and lubrication. So the reality is I need 3 parts. The replacement sleeve – part 23 on the second Diagram (71310952A or 71310952A) The Belleville washer – Part 28 on the Diagram (79910512A) The Special nut – Part 6 above. (75010501A or 75011341A) If anyone has any of these I’d appreciate hearing from you before committing to Ducati prices. Once I’ve got the parts I’ll put the Clutch on to one of my bikes and start playing with building up a stack of plates, which looks like I should be aiming for a total of 36.5mm. I’ve noted the rearmost plate is to be a Friction plate etc. But firstly I have to decide which bike to put the Clutch in. It would probably most suit my 999. The most ‘trick’ of my bikes is my 1000SS/900SL hybrid, so it would add to that. But the easiest one to play with would be my M1000, which being un-faired allows easier access to play with it. Luckily all three should require the same M20 nut, so I can change my mind.
Welcome to the land of slip-grab-stall-slip-grab-stall-slip-grab-stall ad-infinitum. Welcome to the land of mysteriously broken spider-springs. I had a Sigma performance slipper in my 748R. It worked ok as long as it was regularly serviced. Then I got a 1098 and transferred it over. And the above became my enemies. Never did manage to sort it. Eventually #1 on up-hill starts caused me to remove it and hurl it at the garage wall. (Ok, the last bit isn’t quite true but you get my gist)
Thanks Razz, I think. As suggested the main reason for me buying it was curiosity really, having seen them discussed so often. And of course to promote discussion. I'm almost convinced it will come off whichever bike it ends up on and get sold again.
What you have, is the later style of slipper clutch most associated with the 1098R and not the 748R which was much less sophisticated, using only 3 ramps and no balls. It would have come with an aluminium outer basket and uses aluminium friction plates and steel pressure plates. There are 2 sizes of nuts, the small is for the 748R, the larger for the 1098R. Have never owned a 999 so not sure but suspect it would use the larger of the 2. I have various spares for slipper clutches so will have a dig around. Pretty sure I also have colour assembly instructions for the DP slipper, just a case of finding them. It isn’t an exact science and there are tweeks to adjust the feel and feed. As has been mentioned, maintenance and cleanliness are crucial to the slipper’s performance. Andy
Thanks Andy, appreciate it. I have Aluminium Friction Plates, both old and new, plus a stack of plain plates in different thicknesses and a couple of spare dished ones, so am confident I can build a Stack Height as close to 36.5mm as possible. And play with the stack height afterwards if required. Regarding the nut, I've not stripped the 999 down again to measure the shaft size, but coincidentally had the pressure plate and plates out of my M1000 over the weekend so could measure it at M20. The nut part number for the M/SS1000 DS engine is listed as being for a whole range of bikes, including the 999, 999S etc, so they should be the same. - M20, but not sure if that's the big one, Small one, early, or late one? I don't have an Aluminium basket at all, but all my bikes have good enough condition Banded steel ones, which for my purposes will be fine. The Belleville washer or special spacer I don't have, although I could machine the spacer if I had one to copy. Oh, and I believe it was you who previously posted the installation instructions, which I've stolen already
I 'tried' the old 748R type on my 916, it was cheap. It was shagged thats why it was cheap. I gave it away on ebay. I bought a sigma inner and matched it to the 48t basket from STM. I used that on my 916, its still on it. I bought an STM 48T fro my 1198. I loved it. Meant I could run into roundabouts etc faster without engine breaking affecting me too much. Did I buy them because theyre a gadget and ducati mod above all other considerations? Absolutely. Motowheels do the nut for converting 916 slipper for a 1198. Ive prob still got the nut tbh somewhere (no idea where though and not going in garage till its warmer)
This has really not been my experience. We run a DP slipper on the 900ss track bike and while it was slightly weird to get used to, it has always done precisely what it should, with no problems and no broken springs.
Just bought a new EWR for £200 for the 1199 to go with the Nova close ratio race box. Should make me all of a tenth quicker per lap
I think that the springs break if the inner rises up on the ramps too far before the clutch releases. My clutch was fine in this regard but at the time there were a fair few posts from people trying to source spares because theirs had broken. It was the crap engagement whilst road-riding that I hated. Once moving it was fine. I suspect it would have been fine for race starts too, but gentle engagements with low revs it absolutely hated.
I believe the DP Slippers were Made by Bucci rather than STM- not that it matters as they are pretty much the same (6 post classic type, not the Evo). You can find installation instructions for various types here: https://www.avantiraceparts.co.uk/gallery.php?id=11&gid=2&page=1
I ran an STM evo with the 48 tooth basket for many years with zero issues. swapped it from my 999 to a 748 to a 996 to a 999 again, would buy another if needed.
Thanks for all the replies. I get the impression that in General Slipper Clutches are very much Marmite flavoured. I'm going to carry on gathering all the bits I need to try it, will hope I don't have an accident experimenting with it, then will possibly sell it on after.
@Nasher i consider a slipper clutch as a priority if your fast road/track riding, as it will limit the risk of rear wheel lock up during fast down changes. many may have tails of heroism when riding a big V twin without one fitted, but I find the bike functions better with.
Interesting that you say that Comfysofa. Does yours have the combined central Spacer, Washer and Nut to locate the Spider? Or the separate individual parts?
Never replaced a spider on1 any of the four slippers I have/had. All were with integrated bush/washer. Dab of grease around central bore and on each of the six feet (not really an arachnid is it?) anual regrease ( of the whole assembly) and they are all fine.
Thanks RickyX Having read a whole load of threads on here and the DucatiMS Forum there would appear to be a bit of a link between broken spiders and the use of the 3 part system instead of the newer special one part nut. Assuming the 3 parts are assembled in the correct order, I'm wondering if any movement during assembly allows the spider to become trapped between the separate parts so it can't spin around the shaft as the outer drum section spins on the inner bit. The result being broken springs.
I have been using a Corse slipper since 2017. Surflex alu plates with white lithium grease, Molykote M77 on the ramps. Had to replace the spider spring (this is the beefier version with wider legs) once since the spring got "flat", not giving enough tension anymore.
