K2 / Proflex Riders Group

General => Tech Forum => Topic started by: Ziggy on April 23, 2009, 02:04:14 am

Title: 856 disc adapter?
Post by: Ziggy on April 23, 2009, 02:04:14 am

I'm sure it's here somewhere... but has anyone got any drawings of a disc adapter for an 856?  Or does someone still sell them even?

Cheers  :)

Title: Re: 856 disc adapter?
Post by: Colin on April 23, 2009, 06:06:49 am

Yes, there used to be something available, called a "Hammerhead", made by Mike Hammer.
If you're lucky, Mike might produce some more, possibly for RDS/Callum to stock?
I did a little design review of Mike's latest incarnation of the x56HH a little while ago and I have an idea for a version that I think will be even easier to fit.
See my gallery:
http://idriders.com/proflex/coppermine/thumbnails.php?album=53 (http://idriders.com/proflex/coppermine/thumbnails.php?album=53)

    x56HH                                                                                           My Idea
(http://idriders.com/proflex/coppermine/albums/userpics/10284/normal_x56HH-1_Avid_Juicy-203.JPG) (http://idriders.com/proflex/coppermine/albums/userpics/10284/normal_CJS_Idea-2.JPG)

Fundamentally you need to produce a piece of metal that has 3 holes at critical diameters from the centre of the dropout/axle.
Two are for the disk brake mounting holes and these are:
1.571" / 39.9mm
3.075" / 78.11mm
Plus one for a bolt that goes into the Pre-drilled hole in the dropout (meant for a fender/carrier)
0.984" / 25mm
Finally, it's a good idea to have a 4th hole somewhere else in the dropout to fully stabilise the Adaptor.
This can be wherever you like, see the variation between my idea and the x56HH.

Col.

Title: Re: 856 disc adapter?
Post by: willem on April 23, 2009, 07:06:26 am

I have made 5 or 6 different versions and eventually settled on welding as the best solution.
I found screws and QR clamping to be okay, but sometimes noisy. Combining that with epoxy worked a little better. There's no piece of mind like a good weld job though!

I've got an 856 Large for sale with a welded tab on the swingarm. Send a note if you're interested.

Title: Re: 856 disc adapter?
Post by: Ziggy on April 24, 2009, 02:22:26 am

My welding's nowhere near being up to entrusting my brakes with it!  Epoxy & bolts would be the way forward for me - & I hope I'll be able to live with the noise...  Thanks for the offer on the frame, but I've no use for a Large, or space for any another 856 for that matter!  :)

I'm aware of the 'hammerhead' - just wish I'd picked one up when RDS still sold them.  They're not available anywhere else are they?

Thanks for the pics & dimensions Colin.  I'd need to know at least the angle between the bolt holes for the caliper mount too... I'm sure I'll manage to work it out with card etc, but it'd be a lot easier if someone had a proper drawing?
 
Anybody want to sell me their Hammerhead?!

Title: Re: 856 disc adapter?
Post by: Colin on April 24, 2009, 05:08:42 am

Sorry, I should have included this link to make my measurements clear:

http://www.hayesdiscbrake.com/pdf/Rear%20QR%20IS.pdf (http://www.hayesdiscbrake.com/pdf/Rear%20QR%20IS.pdf)

Col.

Title: Re: 856 disc adapter?
Post by: Ziggy on April 24, 2009, 05:58:36 am

Duh ::) Of course they'll be at a fixed distance from each other, so I don't need to know the angle at all!

Still, if anyone's got a drawing of an actual 856 hammerhead... or just one lying around that they could stick on a scanner even if they won't part with it!

Thanks  :)

Title: Re: 856 disc adapter?
Post by: Colin on April 24, 2009, 06:57:27 am

Ziggy,
PM'd you.

Colin S

Title: Re: 856 disc adapter?
Post by: sammydog on April 25, 2009, 06:49:00 am

Colin, if you have the dimensions of an adapter can you send it through to me as well. I can PM you my email if you have the dimensions.

Title: Re: 856 disc adapter?
Post by: Colin on May 11, 2009, 07:07:38 am

All of the info that I have is in the above thread.

Col.