3 Bolt Rotor mounting

[Killer]

Hello all,

I am having a tough time mounting my 3 bolt bike rotor (using it due as it is cheap and easily available).

I have designed a plate which helps me bolt the rotor comfortably but the 4 bolt circle is very close (~3mm ) to the bigger hole for the spindle. Also the 4 bolt circle
Is there any other simpler solution for mounting this rotor?

I have attached images of the hub, the plate and the rotor.

http://postimage.org/image/852pkvh85/
http://postimage.org/image/w00hwzcad/

[Killer]

Hello all,

I am having a tough time mounting my 3 bolt bike rotor (using it due as it is cheap and easily available).

I have designed a plate which helps me bolt the rotor comfortably but the 4 bolt circle is very close (~3mm ) to the bigger hole for the spindle. Also the 4 bolt circle
Is there any other simpler solution for mounting this rotor?

I have attached images of the hub, the plate and the rotor.

http://postimage.org/image/852pkvh85/
http://postimage.org/image/w00hwzcad/

[RobbyObby]

I assume you are running into this problem because you are using an aftermarket rotor and aftermarket hub (VW Golf?). If you're dead set on running that rotor, why not machine your own hubs? Or to the contrary, why not machine your own rotors, and run the aftermarket hub? (This is what we did with Golf hubs in 2010). You will have to decide which is more important.
Sorry I can't give you a better answer though. Maybe consider other methods of attachment? Spline? Locating pins?

[Warpspeed]

It looks as though you may be able to drill four new holes in the hub to mount that triangular plate with a suitably larger PCD ?

[Mustafa]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Killer:
... the rotor comfortably but the 4 bolt circle is very close (~3mm ) to the bigger hole for the spindle. Also the 4 bolt circle ...
</div></BLOCKQUOTE>

Hallo Kiran,

Them RTR disc rotors look good but are a pain to work with, trust me, I know them from Baja.

Doesn't the OEM Brake Disc mount on the same small PCD 4 holes on the hub? If so then even that disc would also have the same 3mm clearance.

Are you worried about strength?
Have you calculated stresses?
You could increase the thickness of the '4 hole to 3 hole' plate you designed.

I agree with Robby, machine new disc rotors, if your set on the Hubs.

[Killer]

I have done the same.

If you are not able to view the images

http://postimage.org/image/w00hwzcad/

http://postimage.org/image/852pkvh85/

[Killer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mustafa:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Killer:
... the rotor comfortably but the 4 bolt circle is very close (~3mm ) to the bigger hole for the spindle. Also the 4 bolt circle ...
</div></BLOCKQUOTE>

Hallo Kiran,

Them RTR disc rotors look good but are a pain to work with, trust me, I know them from Baja.

Doesn't the OEM Brake Disc mount on the same small PCD 4 holes on the hub? If so then even that disc would also have the same 3mm clearance.

Are you worried about strength?
Have you calculated stresses?
You could increase the thickness of the '4 hole to 3 hole' plate you designed.

I agree with Robby, machine new disc rotors, if your set on the Hubs. </div></BLOCKQUOTE>

Thanks Mustafa.

Only two rotors are available below 200mm diameter and both of them have 3 bolt mounting.
The PCD of the hub and rotor is 100mm.

I am machining the hub (4140 alloy).

[RollingCamel]

Just a question. Why the 3d sketches and planes?

[Mustafa]

Hmm.. if you haven't yet machined the Hub then I dont see why you cant just redesign it, with a direct mount for the 3 hole disc rotor.

[Killer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mustafa:
Hmm.. if you haven't yet machined the Hub then I dont see why you cant just redesign it, with a direct mount for the 3 hole disc rotor. </div></BLOCKQUOTE>

The problem is with the installation of stud bolts. Teams using a four bolt rotor can use a four leaf pattern for both the hub and the rotor mount(with a 45 degree offset). From what I have seen, the collar for my rotor has to be placed at quite a large offset from the hub face to facilitate installation of the wheel studs.