Grimeca duplex/Laverda front brake question

Ernesto if you are talking about Laverda drum brakes on 3C or SF the Borrani rims front and rear are different the front drum is laced differently to the rear.
As far as the drums themselves go I think if you prize the cover off the speedo drive side of the front drum it will be very similar apart from having the mounting points missing for the drive plate assembly.
 
The spokes on my newly re-spoked 4446 front wheel were 95mm long.
The spokes on the rear wheel (4613 from memory) were 140mm long.
Same hubs, just different lengths due to different dimple angles on the rims.
I think the question is 'are the Grimeca hub drums the same as Laverda hub drums so the same rim (4446) can be used?'
Don't know.
 
Thanks,
like Paul supposed, I mean the duplex brake (2LS) of 750 S and early GT.
Yes, Maurice. The front spokes cross once, the back ones twice.
Grant, my friend wants to restore his 750S with the (missing) Grimeca stuff.
We want to find out, if he has to search only for the side plates or the drum
as well. Think the wheel came with Laverda stuff.
I know that the rims are the same (4446).

Ernesto
 
The Grimeca hub is quite different to the Laverda hub, but they do share the spoke lengths and drum diameter.  Speedo drive has totally different dimensions, so if it is a double sided unit, RH side will not mate up properly.

piet
 
Im pretty sure the Grimeca diameter is smaller than the Laverdas. Will check tomorrow in the garage.

David
 
Peerless said:
Im pretty sure the Grimeca diameter is smaller than the Laverdas. Will check tomorrow in the garage.

David
Click to expand...

They are both specified at 230mm drum diametre... of course there are others, but pretty sure Ernesto is inquiring about a 4LS 230mm jobbie.

Grimeca drums use the speedo drive dimensions of the Laverda disc brake version, still not a straight forward swap though, the backplate needs a bit of modifying to fit the Lav speedo drive.  Laverda drum speedo drive is larger.

piet

 
Ernesto said:
No, about the 2LS for S and GT.
Wouldn't try to use a laverda drum for a 4LS...
David, the rear Grimeca drum is smaller, 200mm.

Ernesto
Click to expand...

Already have a NOS 4LS hub laced to an original Borrani rim, just need to get the speedo drive sussed to fit it to my GTL... been laying around for 4 years now. ::)

piet
 
230mm hub/ Grimeca twin leading shoe or Laverda twin leading shoe cable reaction or linked, same hub I think.
We are not talking about double sided brakes, just simple 2 LS single side. I think hub is the same.

I have a pile of the stuff, just not to hand.

Paul
 
Definitely not the same hub... I have both 2- and 4-LS Grimecas here, couldn't be arsed to get off the sofa and dig them out for a pic though.

Grimeca hubs have ribs between the spoke flanges and do not have the internal air channels of the Laverda hubs.

piet
 
Chucked a couple of Laverda and Grimeca bits together to see what fits what...

Grimeca brakeplate will DEFINITELY NOT fit the Laverda hub without major surgery.  Other way around might work, i didn't bother measuring widths etc.  Grimeca internal ribbing will not clear Laverda bearing boss.  Grimeca also uses a rather simple cooling system with a scoop and air exiting from the sides of the brake plate.  Laverda scoops cooling air and channels it from the centre of the hub to the circumference, exiting in slots next to the spoke flange, a far more positive sophisticated method.

piet
 

Attachments

  • Neu_Grimeca hub.jpg
    Neu_Grimeca hub.jpg
    164.9 KB · Views: 8
  • Neu_Laverda hub.jpg
    Neu_Laverda hub.jpg
    172.1 KB · Views: 8
  • Neu_left Laverda right Grimeca.jpg
    Neu_left Laverda right Grimeca.jpg
    177.8 KB · Views: 11
You must log in or register to reply here.
Back
Top