Z1OwnersClub GB

Possibly asking a stupid question here but are the calipers for the z1 and z900 transferable. Ie. Could you place two new z1 calipers on a z900 I ask as you can get replacement z1. If not are early z650 and 1000 compalitable

Pretty sure all are swapable,just might need to turn forks 180 degrees.

Hi Derek
the Z1 calipers can't be mounted on Z900A4 forks. The distance between the two mounting bolts of a Z1 brake caliper is shorter than the distance between the Z900A4/Z1000A1 mounting bolts! Just measured it on my bikes.
There's allso a difference between the Z900A4 /Z1000A1 brake calipers and the Z1000A2/A3 brake calipers. The most obvious difference is that the first ones are mounted in front of the fork, the second ones behind the fork . Allso is the place where the brake line is attached different. The Z900A4/Z1000A1 calipers have a recess where the brake tube is attached, the Z1000A2/A3 calipers don't have that recess as they have a flexible brake hose all the way down. Just take a look at the different part numbers in the parts catalogue (look at CMS.NL if you don't have a parts catalogue yourself)
Hope I helped you out.
GrtZ
Philippe

Thanks Philippe i think i knew there would be a difference but was hoping in vain it was not, i may have to mesure the holes on the fork legs in case they have been replaced at somepoint in its past,,, (would not surprise me as it has a few differences from standard to say the least) still waiting for delivery after being let down by a courier so fingers crossed for saturday. :-) Thanks again

Hi Derek
as far as I can see on the picture, the front fork seems to be a standard Z900A4 one. Fingers crossed for saturday!
GrtZ
Philippe

Back in the day the year realised that the braking force was pulling against the forks, people started to twist the fork legs round swapping the calipers so that they were behind and the braking force was against the back of the forks

Hi Savage
good question!
Maybe a sign of the times in those days. The big four Japanese manufacturors looked at each other and were involved in a horsepower competition.
Maybe it depended upon what was "in" those days and what was concidered as new and better.( The same goes on today but faster )
They allso got their inspiration at the races and the developments in the latest techniques of braking and road handling of the bikes.
I guess there's a good technical explanation for the change but I don't know it, perhaps someone else does...
GrtZ
Philippe

Philippe wrote:Hi Savage
good question!
Maybe a sign of the times in those days. The big four Japanese manufacturors looked at each other and were involved in a horsepower competition.
Maybe it depended upon what was "in" those days and what was concidered as new and better.( The same goes on today but faster )
They allso got their inspiration at the races and the developments in the latest techniques of braking and road handling of the bikes.
I guess there's a good technical explanation for the change but I don't know it, perhaps someone else does...
GrtZ
Philippe

Aesthetics. There is no difference on the caliper action on the forks. Behind is slightly stronger for the casting of the lugs, because they are compessed onto the fork tube instead off being pulled off. There is some argument for cooling of the caliper is in front of the leg, but, the weight is closer to the centre of gravity if behind, it's all a trade off....

The force on the fork is caused by the friction of the disc and is at a tangent to the contact batch of the pad. It only acts on the aluminium forrk tube, it does not, as some used to say in the day, work to compress of extend the fork, as it has no direct action on the stanchion or spring.

The force to slow the bike is via the spindle, the contact patch of the tyre, pulling backwards, ie not skidding, and the caliper stopping the rotation of the wheel, which makes the wheel into an infinite series of levers pushing back on the wheel spindle against the forward momentum of the bike.

Weight transfer caused by the momentum of the rest of the bike and rider compresses the forks.

Hi guys
thanks to this explanation we know for sure!
@ savage: your question is solved
@ needaz1100r: thank you for explaning it!

GrtZ
Philippe

Hmmm radials.. It's supposed to give better feel as the bolts fix directly in line with the centre of the spindle and the caliper cannot flex off line.

I'm not convinced as 'in theory' this allows the moments of force to build up around the axle point.

If the are bolted 'in line' with the edge of the caliper then there are no 'bending 'forces around the axle and the force is transferred to the fork direcly at 90 degrees.

As always it's arguable...

garyd wrote:Hmmm radials.. It's supposed to give better feel as the bolts fix directly in line with the centre of the spindle and the caliper cannot flex off line.

I'm not convinced as 'in theory' this allows the moments of force to build up around the axle point.

If the are bolted 'in line' with the edge of the caliper then there are no 'bending 'forces around the axle and the force is transferred to the fork direcly at 90 degrees.

As always it's arguable...

I believe radial caliper mounting is to allow changes in disc diameter on GP bikes with riders who could tell the difference.

But it's just a theory!