Using a disc brake hub on a rim brake wheel?

HobbesOnTour

Über Member
Location
The Netherlands
Hi folks,
I just picked up my rear wheel after a hub upgrade and rebuild. The rim is a 36h Ryde Andra 30, the hub was upgraded to a Deore XT.
Now, the hub they used is a disc brake hub and I use rim brakes. In the LBS they'v told me there is no difference in operation. Is this true?
I imagine the hub will be marginally heavier, but that doesn't bother me too much. This is for a tourer that is fairly well laden.
As for the cost, I've paid what was quoted.
I haven't fitted the wheel yet as I'm not 100% sure about whether I should accept it, as is.
My only concern is that this combination will throw up some issues far from home.
I'd appreciate if anyone with more hub knowledge than me has any views.
Many thanks
 

Phaeton

Guru
Location
Oop North (ish)
I'm going to watch this thread because in my uneducated mind it will not make any difference, as long as wheel physically fits in between the rear hanger. But I'm prepared to be educated otherwise.
 
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I like Skol

Hold my beer and watch this....
No real problems, but the spoke flanges on a disc brake wheel are usually closer together due to the clearance required for the disc. On the drive side you have less dish to make room for the cassette and now the disc element is introduced this is also done on the NDS. The result is a slightly thinner wheel that is less resistant to side loads.
 

PapaZita

Veteran
Location
St. Albans
There should be no problems at all.

You might like to put some screws in to protect the disc bolt holes, if it's a 6 bolt hub, or investigate a way to cover the splines, if it's that sort. You never know if you might want to use the wheel in a disc bike at some later date.

No real problems, but the spoke flanges on a disc brake wheel are usually closer together due to the clearance required for the disc. On the drive side you have less dish to make room for the cassette and now the disc element is introduced this is also done on the NDS. The result is a slightly thinner wheel that is less resistant to side loads.
That would certainly be true on a front wheel, where a disc wheel has dish that a rim brake wheel doesn't. I'm not sure there's such a big difference at the rear, although must admit I've not compared any measurements. Even rim brake hubs don't seem to use all the available width for the NDS spokes, and I suspect this is because if they did, they would be so slack as to be almost useless. I've seen disc hubs where it looks like they could have found a few more mm for the NDS flange, if they wanted to. Pushing the NDS flange inboard will even up the tensions between DS and NDS, which is a good thing, and may help to compensate for any loss in strength due to the reduced distance between the flanges.

In practice, seeing the things that MTBers get up to on their disc braked bikes, I think the wheels can be more than adequately strong. :smile:
 

YukonBoy

The Monch
Location
Inside my skull
A rear disc hub has an OLD of 135mm whilst a non disc road hub has an OLD of 130mm. So depends on what spacing your frame is set for as to whether there might be a problem. Many more modern frames have a rear spacing of 132.5mm designed to fit both hub spacing.
 

Ajax Bay

Veteran
Location
East Devon
the hub they used is a disc brake hub and I use rim brakes. In the LBS they'v told me there is no difference in operation. Is this true?
Because the hub will need to allow for the disc (which you'll not attach) on the left hand side, the dishing will be different and the angle of the LHS spokes more acute (and at greater tension) than for a 'normal' rear hub. I think the LBS's 'no difference in operation' is true, but the wheel would be stronger with a 'normal' hub. Seems a bit careless to me, but if I was scrabbling for positives (and accepting the build) you could consider that the wheel offers some future proofing for when you change to disc braking.
 
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HobbesOnTour

HobbesOnTour

Über Member
Location
The Netherlands
A rear disc hub has an OLD of 135mm whilst a non disc road hub has an OLD of 130mm. So depends on what spacing your frame is set for as to whether there might be a problem. Many more modern frames have a rear spacing of 132.5mm designed to fit both hub spacing.
The previous hub was 135 mm so I don't think this will be an issue? The frame is a late 90's MTB frame.

Because the hub will need to allow for the disc (which you'll not attach) on the left hand side, the dishing will be different and the angle of the LHS spokes more acute (and at greater tension) than for a 'normal' rear hub. I think the LBS's 'no difference in operation' is true, but the wheel would be stronger with a 'normal' hub. Seems a bit careless to me, but if I was scrabbling for positives (and accepting the build) you could consider that the wheel offers some future proofing for when you change to disc braking.
I can't imagine I'll be upgrading to disc, but you never know.
Since this is for a loaded touring bike (actually a MTB conversion) I'm concerned about strength and longevity.

One thing I thought was odd is that the spoke length is the same on both sides. My previous hub had different length spokes for drive/non-drive side. That is one advantage, although I'm not aware enough to know if that's the hub design or the disc brake factor.

Many thanks for the inputs thus far.
 
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