FF: Forks Comprehensive Steering stem, with new lay out

[Vincent Brake]

Started this design up. As the current is working bit to much.
I.e. diving far on braking, lifting high on acceleration.
It rides a charm. Indeed hat off.
I came upon this lay out by DavidD. Many thanks to him.
And decided to make a very complete one. With seals, roller bearings, and the conical one for the head races.

 

[Vincent Brake]

Side trust on pivot bearings is taken up by PhBronze rings. with a play of 0.02 mm.
Fixed set up. Only machine the forked link to 33.00.interfe. fit. And locktite them in place with preset distance.
V rings to seal it.
Stainless hollow axle with agian interference fit (heat up for assy) for rigidity.

 

[Vincent Brake]

Steering stem made from seamless St52 steel 5 mm walltickness. And only kept that at the top alu link height. For the clamping bolt makes an indention there, hence loosing up in service, bad for bearings...
On other diameters i kept 3.5 mm wall tickness.

Under the lower race is a PhBronze ring, acting as a Nylos ring. But this one stays good under the assembly conditions.

 

[Vincent Brake]

Conical rings, made my own, to suit the headstock. As they all have a different diameter for the outer ring

 

[Alyson]

It would be nice if a complete Re & Re "plug & play" kit could be had, remove existing parts and install new, that way the OEM original parts could be put away or sold. In this way no machining or fettling required. Easy Peasy as they say somewhere. I'll start saving ...

 

[Chris Launders]

Being one of the first people to install Normans kit I then heard about the ball bearing conversion, which seemed a bit of work to me, so I found a suitable needle roller outer, and an inner that needed shortening (fortunately my neighbour worked at a grinders) and installed them, I just needed to modify the bolt thingy's that holds it all together (to be honest I cannot recall what now, maybe sleeves) and my own thrust washers, so mine is just a parts swap.

 

[timetraveller]

Th kit that I provide does not require the end user to do any machining. It uses the existing cup and cone head races. I have continued to use the Greg Brillus mod of two ball races each side of the rear of the lower link as they are sealed for life bearings and do not require any further sealing to prevent water or dirt entry. It is true that fitting these does mean that opening up they rear eyes in the lower link to take a 32 mm ball races instead of the original one and a quarter inch Oilite bushes but we normally do this for people if they do not have access to local machining facilities. and do not want to send their lower links half way round the world with a risk of the item being lost somewhere. However, those who have been keeping up with things will be aware that I am currently getting new lower links made. Thirty of these with standard dimensions to take Oilite bushes will go to the Spares Company. The rest will be machined from new to take the ball races and be provided with the ball races fitted.
In addition, for those who wish to use my design of hydraulic steering damper that can be supplied ready fitted to the new JE steering stems and the only modification to the bike is to tap out the five sixteenths hole that takes the anchor for the original friction damper to three eighths BSF to take a new stainless steel screwed in anchor pin.
Thus for someone in Alyson's position they can fit the whole kit, JE steering geometry, Greg Brillus ball race mod, hydraulic steering damper and keep every original part, including the original cup and cone bearings, but they would have to buy the new lower link. Literally the only 'machining' is to tap out one hole from a plain 5/16"ths to 3/8 BSF. We are still going to have to find a replacement for the AVO suspension dampers.

 

[davidd]

It would be nice if a complete Re & Re "plug & play" kit could be had, remove existing parts and install new, that way the OEM original parts could be put away or sold. In this way no machining or fettling required. Easy Peasy as they say somewhere. I'll start saving ...

It is pretty easy to do a "plug and play" because both the JE stem and the DD stem can be installed in their most basic iterations. If you want taper rollers and bearings in the links it gets complicated.

There is no handling advantage gained by using taper roller steering bearings. The cups and cones with balls are fine. I designed a taper roller conversion to use in the racer because the lower steering cone broke. This is unusual, but not surprising. The lower bearing pocket was damaged when the bike was purchased and when I found the damage I decided to cast up a new steering head and machine it for the taper rollers, which are 42 mm metric bearings.

But, if the old bits are working fine, the DD stem is a simple swap using all the original parts, including the eccentrics.

On the stem above, I installed the eccentric stops, the FF36 washer, and the FT124 cone, so the purchaser could simply install the stem on his stock bike as a direct replacement. I believe TT can do much the same with a slightly different design.

My local machine shop went out of business a few years ago and I have not made a new batch in years, but can occasionally get some from a far-away machine shop that does a nice job.

Congratulations to Vincent for doing such great work. The Speet brakes should work much better with this mod!

David

 

[andrew peters]

I have Normans JE steering stem, with bearings in the link and the steering damper as described by TT above. I often recommend to other riders, this is an essential mod for Vincents that are ridden fast, and stop!
I kept the ball bearing neck races, they work well and are often found in modern bikes, especially race bikes! Last month I was having a conversation with Keith of Big D Cycle about the JE stem he had fitted to his own Blue Rapide. He is another advocate for ball bearings, telling me of racing Triumphs with ball bearings, they would have it no other way!
BTW Great work as always Mr Speet!

 

[greg brillus]

Impressive bit of machine work there.......however, the dive /rebound rates are controlled by the springs and shocker not so much the change in geometry.......the link eye bearing arrangement looks good if not a little complex.