Getting ready for my first wheel build.

The hub that will be used is a Shimano Deore XT M756, front. This hub is in the online spoke length calculators that are available online. However, the calculators assume that the hub is being used as intended, hence my point of confusion.

I intend to use the hub as a rear in a track frame with 120mm spacing. I will equip it with a solid axle and spacers to make this happen. I will bolt a cog in place where a disc rotor would normally reside. In other words, I will be using the hub BACKWARDS of how the spoke calculator assumes it will be used.

So, do I just use their lengths backwards of what they say? As in, what they say for left I use for right and visa versa? That is the only logical conclusion that I can come up with, but I want to check so that I don't screw this up.

Thanks

So, are you going to pedal this backwards?
OK, I missed the bolt on part.


Why not get a "fixie" hub?

Translate "left side" to "disc side", and "right side" as "non-disc side"

Bolting on a cog (can you really do that?) will effectively extend the shell width, I think, so the calculation won't be spot on. It will probably get you close enough if you do as DiabloScott suggests. But really, why not just get the right hub to begin with?

Wow, the thing some people do when building a bike......

There should be no difference, as long as you add the same size spacer on each side then the rim is still centered in the frame. The wheel doesn't care if you run it forward or backward. The disc side spokes still go on the disc side and the non-disc spokes still go on the non-disc side.

If you are spacing the wheel unevenly, then you will need to take your own measurements and adjust the center to flange measurements to account for the change in dish that will be necessary to center the rim.

What exactly are you trying to say?

Take a look...

VeloSolo Shop - Converted Disc Mount Hubs and Hub Parts

This is what I am doing ^^^

Nothing "wow" about it to me.

YES....you can really do that, without extension of the shell width no less.

VeloSolo Shop - Converted Disc Mount Hubs and Hub Parts

Take a look ^^

I use these hubs on 3 other bikes and I like the idea of having the same hubs on all my bikes that way I only need to keep spare parts for 1 kind of hub.

Secondly, I have become very proficient at adjustment, rebuilding, maintenance of these hubs as such I prefer to stick with them. They are very smooth and stay that way for a long time. I prefer loose ball and there are very few options out there for loose ball. The options that I have are either poorly sealed, poorly built or both. This hub is well built and well sealed.

Thanks, thats basically what I thought

I plan to add 10mm to each side to get it from 100mm to 120mm.

Good advice, thanks for the great post!

OMG! It puts the logo backward! That will never ride correctly!

Really, though, it's kind of a neat trick and looking at it does make it obvious that what I said about extending the shell width was wrong.

That 41/46mm chainline is handy too -- much easier to get out of common cranks that 42.

I am a little skeptical. Bolting on a disc rotor and the shear forces for that use is one thing. For the purpose of securing a cog, and the forces involved, one would think need to be greater than the shear force that six waterbottle cage bolts would give. I do not see any advantage, except that you would not have to worry about a lock ring. What if you decide on a different size cog, are other sizes even available?

I share your gut reaction, but I'm pretty sure my disc brakes can stop me from 20 mph quicker than I can accelerate to 20 mph so the disc interface must be capable of handling that kind of force. Also, the cogs look a bit thicker than a rotor so the force is more distributed.

Cog sizes....15-22 tooth through a few different manufacturers.

I never said it was perfect, there are pros and cons...that can be said about any cog fastening system though. I will give it a go though and post results.

The flange to center dimension has a much smaller effect on spoke length then most of the other factors involved in length calculations. While I aim for the "perfect" lengths when I build I don't get too concerned with a mm + or -. It's not hard to go a MM longer or shorter to compensate if you feel the need too. Andy

41/46mm chainline is if 10mm of spacers per side OR 15mm on one side and 5mm on the other side is used. You can space it however you want. You can space it for a 42mm chainline if you want, as long as you use the right spokes and dish accordingly.

I plan to put 10mm on each side of the hub and use a bottom bracket that will put the chainring in line with the cog...this will involve the use of a BB that is 4mm longer than the pre-existing BB.

Sure, you've got lot's of options. What I meant was that a standard road double crankset with the recommended bottom bracket (including those that use an integrated spindle and leave you no choice) will have a 41mm chainline if you use the inner ring position or a 46mm chainline if you use the outer ring position, so those options are easy.


When I've built singlespeed bikes with hubs made for the purpose they've typically been designed for a 42mm chainline and I've just ended up getting the crank to 41mm and calling it close enough. There are always other options, of course.

Good thinking... except the proper comparison would be stopping time using only the back brake.

I don't see the advantage of your plan. Nevertheless since you already have the hub measurements, the only thing you need to determine is the center line offset.

Understood. You are in Beaverton? You are not far from me. I am in Portland.

I have a single speed with a front only disc brake.

I can stop quicker than I can accelerate. It holds up well.

Would it? Stopping using only the front brake would put as much torque on the hub interface as accelerating to the same speed from a stop with the proposed hub on the rear, would it not? I mean, there are some minor difference with regard to vertical forces to support the riders weight, but I think the start/stop comparison is well within the range of responsible hand waving.

Stopping can have far more force stressing the spokes then accelerating by any human I know of does. Simple measurements shows this. Mark a spot on the road. Line up at it. Now accelerate till you hit 20mph. The moment you reach 20mph squirt the ground with water from your bottle and brake hard. When stopped lay your bike down and walk back to the water mark counting steps, then to the start line recounting steps. You'll see that the distance to accelerate is far longer then to stop. F=MxA. The mass didn't change. A did because the distances were different. The F is what the spokes see. Andy.

Well, that accounts for why you'd want to do such an off-the-beaten-path thing.