joejack951

I'm considering building a new commuter bike and would like to use a disc front brake on it (spare me the disc vs. rim brake discussion, my mind is made up there ). I never realized how rare 700c disc brake wheels were until I started looking for a set. I found the Cane Creek Strados wheels for $400 which look like they'd do the trick for me as they appear to have a rim brake rim as well as disc hubs (I'll be using a cantilever brake on the rear).

I'm attempting to get some cost out of my proposed build though and while looking at options for doing that I got the idea of using a set of wheels that I already own to build this bike. The wheels are Mavic Open Pro rims with Ultegra hubs. My idea was that I could remove the Ultegra hub from the front wheel and replace it with a 6 bolt disc hub (along with new spokes if necessary) and save myself close to $300. Am I missing something obvious? I'd love if I could do this as not only would it be a fun experience building a wheel but my commuter dream bike will be much more likely to happen if I can axe that much cost off the build.

Hobartlemagne 

I bought a dimension cyclocross fork for the same purpose. Its cheap and tough.

Reusing spokes is discouraged by mechanics and a bunch of cyclists too, but Im not
sure how much the risk of a broken spoke is if its reused.

Don't forget to buy the disc brake itself.

I recommend a Salsa brake handle to get the necessary pull.

HillRider

The Cane Creek wheel does seem absurdly high priced. You should be able to get well under $400 even with all new components.

How good is the shape of your current Open Pro rim? If it's worn, it's not the most expensive part of the wheel so a new rim is in order.

I'd contact both your LBS and one of the bigger mail order placed like Colorado Cyclist and get a quote on a 700c rim laced to a disc hub. I expect any disc-type MTB front hub with a normal axle should be good.

BCRider

I just got a set of XT hub wheels with 700c rims for 29'ers and cyclocross bikes from the Ebay store Rocky Mountain Cycles. The set was less than $200 after the dust settled.

If you want to build your own then go for it. But I would suggest that you just buy the rims and hubs yourself and get the spokes. If you try to re-hub an existing wheelset you'll need to ensure that the spoke hole diameter is the same. And I don't think that is all that likely to be the case.

About 8 years ago I modified a Speciallized Stumpjumper M4 into a disc braked 700c commuter with some fancy Mavic rims and butted spokes. Being disc brakes the bike doesn't care what the rim size is. They have been doing yoeman's duty without complaint for all this time and are still going strong in all weather conditions short of ice.

Shortly after I went to all this trouble Kona and other companies came out with disc brake equipped super hybrids like the Dr Dew for a lot less money..... *sigh*.....

christama

You could get something like an Open Pro laced to a Deore disk hub for pretty cheap.

Hobartlemagne 

Thats what I did. Bought the whole deal and the wheelbuilding at universalcycles.com.

joejack951

Thanks for all of the replies.

The plan is to use an Avid BB7 road disc brake caliper with 105 or Ultegra levers. I'm all set there.

For the front wheel, the reason I thought of using the existing wheelset as a starting point is that the wheels have less than 1000 miles on them and I won't have any use for them once I sell the road bike that they are currently on (part of the process of getting the new commuter).

I figured that I'd probably need new spokes but not because of the spoke hole diameter which is a good point though. I was concerned more with the flange diameter (not sure if it's really an issue going from Shimano Ultegra hub to Shimano XT hub). I found an XT disc hub for ~$40 last night which would make for a really cheap front wheel even with all new spokes and a new rim (certainly less than $400).

My main concern and the reason I initially posted was that I wasn't sure if the Open Pro rim could be safely used with a disc hub. I saw no reason why not and everyone seems to have confirmed my assumption. Now I just need to decide if I want to bother breaking up a wheelset or if I should just bite the bullet and get/build a whole new set of wheels.

TurboTurtle

XT/Open Pro works fine. - TF

HillRider

I'm really not sure about this but aren't disc front wheels also dished like rear wheels to allow for the space taken up by the disc and attaching flange? If so, does a disc front wheel require two different spoke length?

BCRider

Yes they are and yes they do. Unless one side of the flange is slightly different from the other such that you can use the same length spokes each side. I can't say I've seen that.

joejack951

Thanks for the real-world confirmation. Very nice setup too. I'd use a rear disc brake but I need a rack on the bike and don't want to install the rack using the rear quick release (the only option I've seen). I use my front brake the most anyway.

The point about two different spoke lengths is a good one. I assumed this to be the case but again I'm glad to see the confirmation. I'll definitely talk with people who have done this before before I order my parts.

ultraman6970

HI... My project is something quite similar but im using a Scott SUB 20. I got the same issue with the disc wheels. Well I got the cane creek strados, are in sale right now at Cane creek, no brainer for 275 bucks shipping included. A good pair of disc hubs can go for 150 - 250 the pair plus new spokes and stuff... since cane creek is trying to get rid off of all the road and mtb, cane creek it self is the place to go.

I got a cyclocross carbon fork at ebay like for 150, and with I.S disc adapters.

Since I'm going with campy Flat Bar brifters I believe i'm going to end up with a sweet ride (all campy stuff) as soon I can get a pair of BB5's for cheap somewhere Anybody knows where i can get that for cheap???

Thanks.

operator

Spoke hole diameter? Wtf? Spoke length is highly unlikely to be the same between two different sets of hubs, if that's what you meant.

joejack951

8 months later...I bought the XT M756 6 bolt disc hub, a new Open Pro rim, and new Wheelsmith spokes and nipples. The wheel is built, evenly tensioned, and trued. Most people would be happy with that but I'm not entirely pleased.

I used two different spoke length calculators (SpoCalc and DT Swiss's). Both yielded 291.7 left and 292.7 right (well DT said 292.6). Given that I seemed to have a consensus, I went ahead and ordered 292 spokes to use for both sides. Given everything I've read, rounding up this tiny amount should not have been an issue though I did think it was a bit odd that the spoke lengths would be so similar (in hindsight, I should have looked for a third opinion). I lace up the wheel and everything is going great until I start really getting close to final tension (I aimed for and achieved 110 kgf on the disc side using 2.0/1.8/2.0 spokes). The disc side spokes were starting to poke through the nipples and by the time I had the wheel fully tensioned, all looked as though they had used up every available thread or were within a quarter turn of doing so. I'm certain of this because I compared an extra spoke with the nipple threaded all the way on with the ones on my wheel. Also, a few nipples made that characteristic noise of bottoming out during the final tweak.

So the wheel is at tension (for now) and going a little lower probably wouldn't hurt anything as far as I know. If as the wheel breaks in things loosen up, I can just even out the tension (at a lower spec) and let it go. It still really bugs me that the numbers that I was so certain about didn't work out right.

What could have gone wrong with the calculators? 290 and 292 would have been perfect if not a tad long (the non-disc side had the spokes all the way to the tops of the nipples). I've seriously considered respoking the wheel to fix this minor/non-issue but so far have managed to stop myself from wasting any more time.

Here's the almost finished (needs rack, fenders, and lights still) bike by the way, if anyone is interested:

DannoXYZ 

Looks pretty good! I'm considering a front disc on my road bike for downhilling as well. Getting a bit of brake-fade near the bottom of a 7-mile hill, might be able to squeeze out a couple more seconds of speed with discs. On the 3.5-mile downhill, there's no problem with fade, so I doubt it would help there.

Anyway, the issue with the spoke-calculators is the initial data entered. When I helped developed the SpokeCalc programme for Bike'alog back in the early '90s, we used data from the Sutherland's manual. Feedback from the field indicated that some of the measurements were incorrect and we'd run down to the shop and measure the actual hubs or rims in questions and yep, they were off by a millimeter or two. I came up with a technique of laying a ruler across the rim-edges and dropping a depth-gauge down to the spoke-nipple seating-surface to come up with ERD.

So.. I suspect that Wheelsmith & DT maybe sharing the same data-tables with each other or just accepting the manufacturer's dimensions without actually measuring themselves. I find it's best to have the parts in hand and measure them myself before entering any data into the calculators. A lot of times, the online calculator's data is off by a millimeter or two.

joejack951

Downhill braking in the rain is why I went to a front disc. My current commuter's rims are pretty much trashed after 15,000 commuting miles and a lot of v-brake pads.

Given the popularity of Open Pro's, I suspect it must be a dimension for the hub that is off. Of course, with it assembled it's quite difficult to take any measurements. A smarter man might have double checked the measurements prior to building the wheel but I'm not that guy

Why doesn't Shimano publish this information for their hubs? The included information with the hub is 95% about how to tigthen the quick release with two pictures devoted to how to lace the hub. What a waste of paper.