Wilbers Shocks

I could be wrong but I don't think Grant changed wheelbase, steering head angle or trail, which is easily done by changing the rear ride height as well as structural alterations at the headstock, Grant? maybe the forks are longer, which changes it all again.
CLEM
 
Some folk might just weld on stuff freehand, mine was done professionally.
The headstock was extended downwards 60mm and braced back to the frame, then line bored parallel to the top bearing seat. As a result the non-parallel steering stem to head angle was corrected to parallel by removing the steering stem, welding up the holes and fitting a 60mm longer stem. This can be seen by the now eccentric position of the top yoke nut.
The swingarm spindle hole and bushes were opened up from 14 to 16mm to allow an SFC750 spindle to be used.
The pivot point was double skinned beforehand.
The swingarm cross piece near the spindle was removed and replaced with a square section piece at the same time the triangulation/shock mount was done.


IMG_5665 by Grant Duguid, on Flickr

IMG_1515 by Grant Duguid, on Flickr

IMG_5667 by Grant Duguid, on Flickr
 
Cool Stuff! Maybe you do a seperate thread?
Cantilever of course is a upgrade, but I go for twin shocks on classics, not only for the look but also for the raw ride...
 
f you are thinking about the swing arm Nickdav7 (or should I call you Davyninepoints!) then the ride height has to remain the same if you do not want a change of rake and trail, but grant has changed that anyway with his parallel yolk mod, and the chain run position regarding the height it crosses the swing arm is a vital point as well, the chain is inevitable rubbing the bearing housing on  most bikes and especially moto-crossers, if it is higher, then "squat" take place easily because of the angle of the chain from  gearbox sprocket to back wheel is altered and changes the leverage effect making it easier for this to happen when you don't want it, Honda had this problem with the Mike Hailwood Honda 500/4 and it would unload the rear tyre exiting corners and limiting the amount of power that mike could lay down, they never solved it, and nor did Lister of Ken Sprayson (Reynolds tube co) with special frames for this bike made without the knowledge of Honda (in the beginning) because the crankshaft was rotating backwards, and the inertia from that caused the horrendous handling problems that SMBH didn't seem to care much about, very exiting to watch though!
CLEM
 
Not really Clem, I was thinking about the wholsale design mod of the monoshock and the wholly different stresses and stress points from what the frame was designed for, and querying whether anyone had actually done any sums to check..seems not. When my builders put in a rsj support one time, the structural engineer did the sums..and made them replace it with a bigger one. I think a lot of bike mods are done on a wing and a prayer..you seen those single swing arm Blades ever? Do they do the sums or just what seems ok. Mind you, presumably someone did the sums on the Wobbly bridge, and got them wrong ?!
 
To do a sttuctural analisus yoi need to know what load is to be applied.How you measure that and design arroind it I have no idea other than applying previus expirance.In home building you usr live load tables for exprcted use.You see a lot of decks and balcanys fail when huge loads happen at partys .Sticky rubber big power and brakes put big loads on frame and suspention.Not back yard work calculatimg these forces so expetiance rules i spose
 
..some people dont know their history😉.those chines were pretty clever even then, and dab hands with an abacus😁Besides,which,  its one thing to drag along a sled with stone wheels , another to put 100bhp through a wheel...things have moved on just a touch since the wheel was invented. The point is , of course you can do stuff without calculating, it just seems a touch random to me. Do the engineers out there, because I am not one, have a  learned view?
 
Laverdalothar said:
I agree, that one change can almost "force" the next. If the bike else is standard, Ikons are good shocks and an improvement over the original ones, no doubt. If you are planning to transform your bike into an almost modern riding feeling, this as said before will need you to modify every single step. Forks - at least speaking for my 38mm Marzocchis - can be made to work very good, but they need at least some attention (and in my case a stabiliser), too. Went on that journey years ago, coming from worn out Marzocchi AG Strada to Konis at that time. felt the bike to improve dramatically, but now the fork was to soft. changed the springs, the oil, pre-load and installed the stabiliser. Was OK for some years. Then I changed to box-type swing arm with needle bearings, which improved the riding also. Then Piet introduced me to the GSX-R rims. Now the whole setup needed to be much more sensible and the Konis simply were not doing a good job here I felt. Changed to YSS and all of a sudden, the bike handled like a good bike from mid 90's! No problem to keep up with my wife's brother's VFR750 (RC36) anymore! Handling is a dream on that bike, no where near the way it handled when I got it 1992...

So - will Wilbers be good to your bike? Yes, they will. Will you make the most out of them? Not without other modifications.
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Yes I see the point ..... thanks
 
nick7 said:
..some people dont know their history😉.those chines were pretty clever even then, and dab hands with an abacus😁Besides,which,  its one thing to drag along a sled with stone wheels , another to put 100bhp through a wheel...things have moved on just a touch since the wheel was invented. The point is , of course you can do stuff without calculating, it just seems a touch random to me. Do the engineers out there, because I am not one, have a  learned view?
Click to expand...

Most people with basic mechanical training can estimate what works and what doesn't.  Those with deeper insight to engineering certainly do basic calculations, just to be sure.  Then add 10-30% of whatever is required, or more, depending on how critical the component is to safety, and bob's your uncle...

Experience does help to make things look easy to the un-knowing. :D

piet
 
I think if there are safety parameters inherent in a std design, then you can work within those when thinking about modifications. I agree with Piet that if you have experience and aptitude then a lot of the 'calculating' should be inherent in your work.

If I were thinking of a monoshock for a triple, using a stock swingarm with bracing (as Grant has done),  I'd assume that if the std item worked 'OK' and was safe, then there's no particular reason it would be weaker in its new config. Sure, there will be a shift in stresses to some degree, but a swingarm working with a twin shock isn't suddenly going to twist and warp because its suspension contact point has moved to the centre (not even taking into account that the shock bracket is also a brace).

Another example: is a different spoke wheel strong enough to cope with extra power? On my SF1 used a hub from a Z1000 Kawasaki - heavier, more powerful - so i assumed it could cope with my bike. SFQ has a rear wheel from a modern 900cc Triumph - more power (maybe) and probably similar weight; take into account the safety margin a major manufacturer builds in and I'm confident I have a workable option. No calculations, just common sense and 'instinct' based on decades of experience.

Once you get into racing, it's a different story, because factors like weight-to-strength-ratio become critical, and the consequences of 'bad calculations' can be extremely serious. There are plenty of race bike builders who have built amazing stuff based on instinct, and plenty who've seen failures because they're pushing the limits.
 
To quote a lot of racers something btoke and I became a pasinger.Even in F1 where they have more money than god.Even Laverda,Guess why the factory came up with those frame gussets.
 
nick7 said:
Do the engineers out there, because I am not one, have a  learned view?
Click to expand...

Yes. But we don't do stress calculations for everything. As has been said previously, a lot of engineering design is based on what has worked (or not worked) before, or 'rules of thumb' that have been developed with experience. It's a kind of evolution process, and there are sometimes failures. Most of us have seen videos of spectacular failures like the Tecoma Narrows Bridge or the Hindenburg. We probably learn more from failures than from successes.

Anyway, you don't need to be an engineer to come up with an elegant and functional design. There are plenty of clever and creative people in the world.
 
Anyway, you don't need to be an engineer to come up with an elegant and functional design. There are plenty of clever and creative people in the world.

John Britten come to mind
 
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