Having just come back to the fold with a 996 my first task is to swap wheels to something other than the 3 spokes. 848 wheels look like favorite but I am aware that, although the rear goes straight on in, the front is a bit awkward. I know the basic issues are disc mounting bolt pattern/qty is different and that the speedo drive needs help plus an offset issue (presumably the brake disc position). Has anyone got a definite installation guide on what I need to do to get the front to fit. I have no intention of changing fork legs and brake calipers but looking for a solution that adapts existing to mate with the 848 wheel.
Why not look for a set of 5 Spoke Marchesinis. They are not cheap, but do come up for sale frequently. Aly ones not the magnesium ones
The 5-spoke Marchesinis have been considered and are the fall back option if using 848 wheels is too expensive.
As above, the wheel will fit but no speedo drive and the discs will be a problem due to the 5-hole setup that AFAIK are all 15mm offset. Marchesini make or at least made 10-spoke wheels for 916, I have them on mine.
Still trying to understand a solution for the 848 front wheel in the 996. I'm ignoring the brake disc offset issue at this stage as I know that can be resolved and sticking with working out the feasibility of the speedo drive. Current thinking is that the speedo drive is mechanically clamped into position once the spindle is torqued up. However, as there is a lug on the speedo drive presumably this is captured to stop the drive from spinning - looking at my bike I can't obviously see if it locks into anything or not and, looking at images of fork legs, there's nothing visible on the leg that it mates to. From what I can tell the speedo drive is driven by a "relay drive ring" part no. 1-000-674-390 which sits within the wheel itself. By the looks of things this is retained in position within the front wheel by two legs protruding at 180 degs apart. Task therefore becomes : - identifying how the speedo drive is retained in position using the lug or another method - confirming the mechanism of how the speedo drive is turned Once the above is understood there then comes the engineering task of finding the simplest adaptations to make that don't cause any compromise to any rather important components. As soon as a few parts arrive then I can get to work on the task at hand!
I've got a cheap standard 848 wheel available in Durham. Its true but has a few marks here and there from being used for track wets. Would be ideal to experiment with and powder coating could be freshened up if it all works out. Drop me a message if its of any use.
Too much of a newbie I think to be able to DM you but am interested in the wheel. Have an offer out on one currently but that's not 100% to come off.
I'd love a set but unfortunately my wife might not agree. And, as I've started on this quest to fit an 848 front wheel and retain the speedo drive then I need to prove to myself it's impossible before flying the white flag and going the easy route!
The lug is on the plastic mudguard bracket. The Speedo drive itself isn't clamped at all but free floating. The cable only allows it to rotate so far but the definitive stop is on the mudguard bracket. The lower left bracket is different to the other 3. Picture attached.
As above, there is a locating lug in the plastic mudguard clamping bracket but it only acts as a guide and the speedo drive will stay in place perfectly well without it. I had some PVM fork bottoms that had no such lug as the mudguard brackets were cast into them and they fitted fine with the speedo drive etc. - until one broke, but that's another story. As such the 848 wheel will fit with the correct spacers etc. but you won't get the speedo drive in because the bearing sits in the end of the hub rather than being recessed into it so the speedo drive assembly won't fit into the wheel and there's no way you'll get round that.
Pretty sure that the speedo unit is clamped up when the spindle is torqued up and doesn't float. That's how it was on my 748 and 916.
Isn't it the inside sleeve is clamped up but the plastic exterior can still rotate? Been a while since I was in there.
So the issue is the bearings being positioned further away from the wheel centre line on an 848 and leaving insufficient room for the speedo drive of the earlier models. Will have to go the route of x-raying an 848 and 996 wheel to ascertain how much material exists inboard of the current bearing seat and comparing the two. Potentially some space can be gained by machining the bearing seat deeper. The speedo drive unit also has capacity for some width reduction - not very much but any will help. Also the option of slightly narrower bearings exists but, a) that's not a preferred route and, b) would need to get some very exact loading specs. for the bearings before going down that road. Not out of this one yet. And the easy solution is probably and Marchesini M10RS front wheel in conjunction with the standard 848 rear. Probably quite difficult to see the difference between the two with all the front brake paraphernalia in the way - sadly the 3-4 month wait isn't preferred.
I think you'll find that the bearing seat is, for weight reduction purposes, only as thick as it needs to be for the hub casting strength and so if you try to machine it down, you'll cut away all the material and be left with a hole? but it's easy enough to measure the thickness using a vernier, I doubt it's more than 10mm and you don't want to reduce it or the wheel might collapse. Best bet, IMHO is to locate a front Marchesini for 916 (like mine in the pic above) which is the lightweight, modern 10-spoke design but made for the 916 so has the speedo cutout and correct disc offset/hole layout though they are probably no longer available new... To add, it seems the Marchesini are still available, £770 for the front, £1800 the pair; https://www.bikehps.com/acatalog/Marchesini_M10RS_Kompe_Wheels_Ducati_916.html
Agreed on the locating of a Marchesini .... but I've not found any circulating on the used market - not even old listings - and the wait until the end of the year means it's worth seeing how unfeasible the fitment is or not. There are a few very clever bods in the aerospace industry that I can engage with and get a bit of advice but agree that there may just not be enough meat left to play with.
