Disc brake calliper mount

[graeme]

IMG_0156.JPG

Honda NSR125 forks on a 450.
The calliper bolt mounts are 10 x 1.25.
The forks have an 8mm hole.
My question is, looking at the fork lugs does it look like there is enough alloy to drill the fork lugs to 10mm ?
And be safe ?
there is 6.3mm of meat at the thinest part of the mount. The lugs are 23mm wide

Graeme

[Duccout]

Those lugs look to have at least as much meat around the hole as Marzocchi forks do, so I would guess that it would be OK, but I'm not an engineer. It would be important to drill and tap the holes in the same plane as the spindle faces to avoid stresses, so it needs to be done well. Maybe Nigel Or Eldert will give you their opinion.

So those fork legs fit the yokes? 32mm? Some find if they do!

[graeme]

35mm Showa
I am using the triple clamps from the NSR also.
The calliper will be behind the fork leg so the braking force will be pushing toward the leg not pulling away from it.
The 10mm bolt passes through the fork lug and bolts into the calliper
So I would only need to enlarge the existing 8mm hole to 10mm

Graeme

[Dan C]

Assume its a brembo caliper?
I can't remember if the caliper is threaded.
If it is could you use a helicoil to bring it down to 8mm thread?
If it isn't then maybe sleeve it down to 8mm?

[Duccout]

I can't see that it would be a problem. Give us a picture when it is finished!

[DBDBrian]

What about making 10 x 8 stepped studs, and retain it with 8 mm nuts.

[Eldert]

the 35 mm Showa forks from a Honda125 NSR jc22 are very nice forks . they have bushings to eliminate stick-slip .

furthermore they have a i.d. of 30 mm just like a Ceriani GP fork

nice and lite forks .

what caliper are you planning on using ? the c.t.c. distance of the lugs is 65 mm

Eldert

[graeme]

Hello Eldert,

I have a left hand P4 30/34 that is 65mm mount.
I will see how this fits with a 280 disc on these forks. ???
If it doesn't work with the disc for a 4 bolt hub (same as disc yellow single) I'll look around for a disc and maybe a calliper from a dirt bike.
4 bolt disc choice is limited as most are 5 bolt now days.
Much measuring to do ,,,,,,

Regards
Graeme

[graeme]

And , yes the JC22 Showa forks do look to be well made and as you said, they are light.

[graeme]

Back to the drawing board,,,,,
280 disc has too much off set
P4 calliper ?? not sure until I source a disc that allows the wheel to be centred.
May have to make new 6 bolt disc carriers to allow for more range of disc to choose.
The 40 spoke hub is 4 or 6 bolt.
Might be better off buying a disc, calliper and axle from a NSR jc22.

Graeme