Anyone have success finding triple-clamps/yokes of similar offset (20mm +5/-0) as the Marzocchi or Ceriani FI kit? Let's just say someone wished to fit cartridge type forks (like some of the last Showas prior to USD everything) and really wanted clamps of good rigidity such as Harris, Kosman or the like but then discovered nearly all newer yokes are 30mm offset or a bit more – any possibilities?

Thanks,

FMcD

Hi Fran,
Those forks are probably the future of conventional vintage race legal forks. I've been wondering about picking up a set myself, but haven't done any research yet. Is there a particular make/model/year bike that came with an especially good cartridge equipped set to keep an eye out for? There could be small market for good triple clamps with the proper offset like you describe for our bikes. And I'm also guessing there would be a need for caliper mounting adapter plates for our Brembo calipers and 280/300mm rotors. Maybe Carlo is listening...
Bill

Fran, I had the need to find a competent ISO machine shop for a special project at work.
The result of my search led me to an aerospace shop close to my house and equipped with all the latest and best equipment.
If we( at least 5 ) could supply them with dimensions and or drawings they would make whatever we need. They have a waterjet capable of cutting 6 inch thick alloy, to cut down on machine cost and time.
I had them edm an internal spline in some very large pumps, great work fast and reasonable.
Paul

check out what r6 are.

Been chatting about this topic in the Curtis Yellow Bike frame kit discussion.. We concluded that we'd need to go for a dropped upper triple as per the DB1R. I plan to run it past my local CNC guy, but I like the sound of Huit's connection as well. Paul, I'll send you what I've got after I see my local guy.

Brad, I've had to do my searching on the interweb and what a bleedin' arsepain that gets to be. Reports vary but near as I can tell R6 '99 on are 30mm with '99 R1 possible (not verified) 25mm offset but USD forks. Have to say I've dithered away many hours following conversations of punters nattering endlessly but it does appear ≥30mm of offset is very much the majority. Seems the retrofit of F1 Ducatis and TT2 variants is a family matter, may be genetic. 20mm offset allowed crap ...er, classic era forks to blunder along well above their capability level so in actual fact we may not need those clamps. Thing is, 30mm contributes to very nice turn-in but is a bit less tolerant of setup issues elsewhere. If Steve and Paul get together and build something in the 25mm offset range or best yet adjustable offset like Harris Magnum, Traxxion, Spondon etc. within the parameters of lightweight and strong, I'm in like Flynn.

Vintage and Classic eligibility negates adapting USD forks and also limits tube dia. to 41mm for the classic period to 1982 round these parts. P4 is much more tolerant but technology is unkind to TT2/F1 kit bravely racing in classes for 1989 machinery. AHRMA rules approximate these definitions. It gets quiet when news the pre-'83 group is limited to non-cartridge type forks is mentioned...

Hey Fran. What size is the tubes on the set you want to use? Any photo of what you are talking about? MikeV

Hi Guys, Be careful what you wish for here. There is a consequence of having less offset/more trail, with the fork legs hitting the lower frame tubes on full lock (which is already substantially less than "full") This is made somewhat worse by using larger diameter fork tubes and triple clamps, as they form a fork/frame lock stop even sooner.
The original TT2 cast marzocchi yokes are a motocross item chosen for their low offset (25mm).
These clearly use 35mm forks and are a about as tight as you can get before you engage the above frame issue.

I machine my own cnc adjustable triple clamps which adjust in 5 steps with reversible inserts.
195mm (std) centres adjust from 28mm to 52mm. 35mm and 38mm dia available
180mm centres adjust from 24 to 48mm. Only one set of 38mm left on the shelf
205mm centres adjust from 22 to 46mm. 41.7mm dia, 2 sets available.
All £450 a set.

Also have the early cast triple clamps for 35mm forks at 170mm centres. £220 a set.

The other way to resolve it all is to have the frames with more kick back on the lower tubes.

I like this thread, some technical concepts I needed re-acquaint myself with so I could follow the conversation.

I did some research... and found this great explanation of Offset etc and why it matters...

The animations below are described here: http://gotagteam.com/blog/2011/05/20/ba ... nd-7-2010/

Glyn's got a point (and some beautiful triples).
However, for reference, I ran 25mm offset Marzocchi clamps with 195mm centers on my TT1 (DM Verlicchi replica) with M1Rs and after spacing the lower bearings to allow the lower triple to clear the tubes, steering lock was acceptable. On an F1 the larger tubes wouldn't be an issue, but in either application, you'd probably have to run 200 - 205mm spacing to accommodate most hub widths. Although this would also give you more lock...

But, a dropped upper triple (to make up the fork tube length) will still be limited by the F1 (and TT) upper frame tubes.

If it was easy, it wouldn't be any fun..