Disk vs. non-disk hub musing

[Baird Webel]

I've been considering building a new wheelset for our tandem. We are fairly light and I've very good
luck with respacing single bike Deore XT hubs out to 145. I don't have a disk brake setup but was
thinking of using a disk hub for the rear just to have the option in the future.

In looking at the specs on the shimano hubs, I was kind surprised at the difference between the
non-disk, FH-750 and the disk model, FH-756. The 750 has a center to right flange distance of
23.2mm, center to left is 36.8. On the 756, the center to right is 18.5, the center to left is
32.15. The difference on the left side is no surprise, you need the space for the disk, but what I
don't understand is the difference on the right hand side. I can't think of any reason why you would
change the right side of the hub because you added a disk brake on the left. The flange on the disk
hub is high, vs. low for the non-disk, but I don't know why this would make a difference on the
flange spacing either. Anybody have an explanation? Taking that 5mm just adds more dish and weakens
the wheel.

Any speculation on how much strength difference the 60mm vs 40mm flange spacing would make? I'm
assuming that the 40mm still builds a pretty strong wheel given its use on single MTBs. This
wheelset would be 700c, which is weaker, but also has much less dish. It would be a backup wheelset,
so it would get relatively little use.

Any thoughts welcome.

Baird

 

[Jamie]

Dude if spacing the axle to 145 you need to think about disk set up.The caliper sit on the frame the
disk mount to the wheel.The spacing is got to be right .you might need a wider axle to put the disk
over where it should be. good luck .I take it the spacers your using are just 1- 5mm nuts on each
side of the axle.

 

[Dianne_1234]

I saw a tandem with 145 mm DT hubs and disc brakes. See

http://www.dtswiss.com/en/naben-huegi-TD.html

for the adapter they use.

Baird Webel <[email protected]> wrote in message news:<BA485749.196F4%[email protected]>...
> I've been considering building a new wheelset for our tandem. We are fairly light and I've very
> good luck with respacing single bike Deore XT hubs out to 145. I don't have a disk brake setup but
> was thinking of using a disk hub for the rear just to have the option in the future.
>
> In looking at the specs on the shimano hubs, I was kind surprised at the difference between the
> non-disk, FH-750 and the disk model, FH-756. The 750 has a center to right flange distance of
> 23.2mm, center to left is 36.8. On the 756, the center to right is 18.5, the center to left is
> 32.15. The difference on the left side is no surprise, you need the space for the disk, but what I
> don't understand is the difference on the right hand side. I can't think of any reason why you
> would change the right side of the hub because you added a disk brake on the left. The flange on
> the disk hub is high, vs. low for the non-disk, but I don't know why this would make a difference
> on the flange spacing either. Anybody have an explanation? Taking that 5mm just adds more dish and
> weakens the wheel.
>
> Any speculation on how much strength difference the 60mm vs 40mm flange spacing would make? I'm
> assuming that the 40mm still builds a pretty strong wheel given its use on single MTBs. This
> wheelset would be 700c, which is weaker, but also has much less dish. It would be a backup
> wheelset, so it would get relatively little use.
>
> Any thoughts welcome.
>
> Baird

 

[Baird Webel]

On 1/14/03 10:10, in article yLVU9.677385$P31.513734@rwcrnsc53, "Jamie" <[email protected]> wrote:

> Dude if spacing the axle to 145 you need to think about disk set up.The caliper sit on the frame
> the disk mount to the wheel.The spacing is got to be right .you might need a wider axle to put the
> disk over where it should be. good luck .I take it the spacers your using are just 1- 5mm nuts on
> each side of the axle.
>
>

Thanks for the suggestion...I am told that I can get a spacer of some kind to sit between the hub
and the rotor and put it back to the proper position for the brake mount.

--
Baird Webel Washington DC