# Interpreting Shimano hub specs



## Metaluna (Aug 26, 2005)

I have a set of wheels with 32h Deore M530 hubs that I want to rebuild with Sun CR18 700c rims. I haven't taken the old wheels apart yet so it's hard to make measurements to enter into spoke length calculators. So, I looked up the hubs on Shimano's website and found some specs, but I'm not sure what to make of them. For example, the rear hub (Part # FH-M530-L) is listed as follows:

OLD: 135mm
Flange Distance: 59.2
Dish: 7.6

So my question is, what exactly is the flange distance? Is it the center-to-center distance between the flanges? I did a rough measurement on my hubs and they seemed about 5mm shorter than the above, but like I said, it was pretty rough.

Secondly, how is the dish measured? is it the offset between the overall centerline of the hub (i.e. OLD / 2) and the centerline between the flanges? 

I'm trying to use these figures to derive the measurements needed for Damon Rinard's Spocalc spreadsheet, but I'm not sure I trust them. Even the front hub is listed with a nonzero dish which doesn't make sense for a non-disc hub.

If anyone has reliable Spocalc entries for this hubset, that would be even better.


----------



## curlybike (Jan 23, 2002)

*Not enough data*

You must have the spoke hole drill pattern diameter. Without that, you are stuck.


----------



## Mark McM (Jun 18, 2005)

Metaluna said:


> I have a set of wheels with 32h Deore M530 hubs that I want to rebuild with Sun CR18 700c rims. I haven't taken the old wheels apart yet so it's hard to make measurements to enter into spoke length calculators. So, I looked up the hubs on Shimano's website and found some specs, but I'm not sure what to make of them. For example, the rear hub (Part # FH-M530-L) is listed as follows:
> 
> OLD: 135mm
> Flange Distance: 59.2
> ...


"Flange distance" is the lateral distance between the flanges. Shimano rear hubs have traditionally been ~55 mm between flange centers, so I'm guessing that the Shimano spec. measures the flange distance outside-to-outside (which would be about 5mm greater than center-to-center). In any case, a few millimeters variation in flange spacing will make negligible difference in spoke length calculation.



Metaluna said:


> Secondly, how is the dish measured? is it the offset between the overall centerline of the hub (i.e. OLD / 2) and the centerline between the flanges? .


That's correct. Without dish, a 59.2 mm flange spacing would give each flange an offset of 29.6 mm from center. With a 7.6 mm dish, the left offset would increase to 37.2 mm and the right offset would decrease to 22 mm.



Metaluna said:


> I'm trying to use these figures to derive the measurements needed for Damon Rinard's Spocalc spreadsheet, but I'm not sure I trust them. Even the front hub is listed with a nonzero dish which doesn't make sense for a non-disc hub.


Are you sure the Deore front hub is non-disc? According to the Shimano web page, the HB-M530-L is centerlock compatible (Centerlock is Shimano's rotor mounting interface).


----------



## Metaluna (Aug 26, 2005)

curlybike said:


> You must have the spoke hole drill pattern diameter. Without that, you are stuck.


PCD is given as 45mm. I didn't mention it because that one matched up with my measurements and seemed pretty straightforward.


----------



## Metaluna (Aug 26, 2005)

Mark McM said:


> "Flange distance" is the lateral distance between the flanges. Shimano rear hubs have traditionally been ~55 mm between flange centers, so I'm guessing that the Shimano spec. measures the flange distance outside-to-outside (which would be about 5mm greater than center-to-center). In any case, a few millimeters variation in flange spacing will make negligible difference in spoke length calculation.


Ahh, okay that makes sense. I measured 2 10/64 inches between centers on my machinist's rule, which works out to 54.8mm (~55mm for all practical purposes). I think this implies that each flange would have to be 4.2mm thick, which seems a bit high. I'll measure the outside flange distance just to make sure.



Mark McM said:


> That's correct. Without dish, a 59.2 mm flange spacing would give each flange an offset of 29.6 mm from center. With a 7.6 mm dish, the left offset would increase to 37.2 mm and the right offset would decrease to 22 mm.


Okay, cool. Thanks for the guidance. This should give me enough information to derive the numbers Spocalc wants (i.e. wheel center to flange center on each side).



Mark McM said:


> Are you sure the Deore front hub is non-disc? According to the Shimano web page, the HB-M530-L is centerlock compatible (Centerlock is Shimano's rotor mounting interface).


Hmm, possibly. Looking at the page again (http://tinyurl.com/gmx2t), there are two front hubs listed, the M530 and M535. In the feature list it says "Center Lock system compatible(M535)", so I was assuming that only applied to the M535, not the M530. I'll have to look more closely at the hub. The Center Lock mount should be pretty hard to miss if it's there.


----------

