Bobby said: Mountain bike parts? I thought this was about fixed gear?
We think it's about innovation, looking at things differently than most everyone else, about never riding a bike that's box-stock right outa the catalog.
The hub at the top in the following photo is a 32H DT/Swiss-Hugi 'Onyx' hub that will actually be the primary focus of this project and the hub to the lower right is a 36H Hayes. Thanks to Ben's Cycle in Milwaukee for providing these hubs.
Both have very similar hub shells, but the Hugi has a larger "drive-side" sealed bearing which would make it better for our use. You could also use a standard fully-threaded axle with a Shimano Deore hub that has a cup and cone bearing system. Converting that type of hub would be much easier for most folks to convert* ... but we like the additional challenge the 'better looking' Hugi hub offers as well as the sealed bearing simplicity.
* One potential drawback to that conversion is that Shimano front mtb hubs generally use 3/32" balls while the rears use 1/8" balls.
Tom Chow, who produced the excellent article on that type of conversion for the Gallery is currently experimenting with
some options for changing race sizes and/or simply replacing the balls. Tom will have an update on that project soon.
The goal with this project is two-fold:
The goal with this project is two-fold:
Miche - review and photos.
Level - review and photos.
Second, we wanted to take advantage of this nice Hugi hub and create the lightest fixed gear wheelset that we could. The target weight of this project is 1550 grams which is comparable to a Campagnolo Record 9 speed hub laced to some Open Pro rims with premium spokes. (including skewers). Remember that published weights in magazines and catalogs typically do not include skewers.
Pictured is the partially disassembled Hugi hub showing the larger 'drive-side' bearing and dust caps. Also installed is a beautiful bit of workmanship - a Boone Tecnologies 16T titanium cog with 5mm titanium torx-head bolts. We used a hydraulic shop press at Garfield Auto Center to disassemble this hub.
But as we learned later in this project, a wooden mallet can easily be used to disassemble a hub like this. Just disassemble any external parts, hold the assembly over something soft to catch it (not over concrete) and thwack the upper end with a wooden mallet or, as I did, with a 2 foot hunk of 2x4.
Fortunate for this project, the inside diameter of the sealed bearings in this Hugi hub is 10mm - same diameter as a rear track axle - very cool.
The mountain bike front hub spacing is 100mm - the same as on a road front hub - so we'll need to add either 20mm of spacers or 26mm depending on what frame you are going to use the wheel on. A quick measurement of regular Dura-Ace threaded axle lock nuts indicated that they were 4.8mm thick, so at least initially, it looked like we could use some stock parts to re-space. After looking and assembling this hub with a fully-threaded 10mm track axle, we realized that while it would be possible to do it this way, the sealed bearing would be sitting on the threaded part of the axle, hardly ideal for several obvious reasons.
So we decided that a new axle was the trick. The first step will be to completely disassemble the hub and, using the original axle as a guide, create a dimensioned drawing of the new threaded axle that we'll need to have machined.
But before we do that we'll need a front hub. I was unable to find a matching Hugi 'Onyx' road front hub, but I was able to find a 32H Ritchey front hub that matches the Onyx profile quite nicely. People tell me Hugi manufactures for many marques, Ritchey included.
Next up was the new axle....My hunt around here in Traverse City for a machinist that could turn a new axle was fruitless - every place I asked the answer was the same "you'll have to go to Grand Rapids or Detroit to find someone to do that." So I asked around a bit more and then eMailed our friend M-189 (Bob Schutter) who actaully lives just west of Grand Rapids.
"Bob, do you know any machinists in Grand Rapids?"
So I tossed all the parts into a box and mailed them off to Bob.
Bob measured the axle and made up a drawing for his brother. Bruce Schutter machined the prototype steel axle, we stacked the parts up, and those folks over at Velocity built up the wheels using double butted spokes and alloy nipples. Remember, we want these wheels as light as possible without going to a low spoke count..
So here's what our prototype looked using various conventional axle parts.
A spacer approximating the thickness of the rear fork ends is shown in all of these photos (red dot). Basically, what we've done is use a pair of inner axle nuts (separated by a washer) on each side of the hub (total ~10mm per side) to respace the hub from 100mm to 120mm. Additional spacers could be added to increase to 126 if you wanted. The two inner axle nuts are 'jammed' together on both sides in such a way as to take up any slack in the axle (there was about 1mm of play, perhaps indicating that a least one bearing needed to be flipped over and re-installed.)
Checking the chainline indicated a 40mm chainline, moving one nut to the driveside squared that minor problem up. But the more I looked at this assembly, the more I realized that jam nuts wouldn't be needed, after all the hub in it's original configuration was basically all held together by the quick release. Why couldn't this set-up be held together by the axle nuts?
Bob and I agreed, so we changed the profile in the next axle as you'll soon see.
The wheelset with steel axle weighs 1770 grams in the prototype configuration shown with 3x Wheelsmith db spokes and alloy nipples laced to Velocity Aerohead rims (non-machined sidewalls). Not too shabby.
Next order of business is to replace the steel axle with a titanium axle which would be also turned by Bruce Schutter in Grand Rapids from titanium billet provided by Brown Technologies. Bob and I collaborated on the drawing, I measured the original axle with a digital vernier caliper and made the drawing.
The prototype steel axle weighed 163 grams and the new Ti axle weighs 73 grams, Bruce turned down the center section to 10mm as well. What a beatiful little piece of engineering - thanks Bruce.
Shown in these final photos is a 15T 1/8" cog from Boone. The 15T cog and three Ti Torx bolts weigh only 19 grams. That compares to just over 100 grams for a regular steel cog and lockring! All this work lowered the weight of our project wheelset to 1,616 grams including the front skewer and both track nuts (steel) in the rear - certainly the lightest fixed wheelset we've laid hands on.
In this final configuration I've used two hollow spacers from my parts bin. I have no idea where they originated, but they worked just perfectly, resulting in a chainline that was off only about 1 mm. The spacer on the drive side is steel and has a serrated face, on the non-drive side you'll see a hollow aluminum spacer and a single serrated-face Dura-Ace track nut. I just snugged up that nut. Perfect.
We slid on some 23mm Vittoria Diamante clinchers that weighed in at 185 grams apiece - 60 grams per tire less than the 23mm Michelin Megamium's that we'd been running on another wheelset. Ultralite Specialized tubes completed our installation.
Now we didn't make out target weight of 1550 grams, but we could get down to about 1580-90 grams by getting a pair of titanium 10mm flange nuts from Race Bolts at eleven bucks apiece, but we'll be missing the swivel washer on regular track nuts.
So will this make a difference in your riding, or ours? Probably not, but a light set of wheels do accelerate faster. What about cost? The Ti billet retails around a hundred bucks, and Bruce said considering the number of times he had to sharpen his tools - well maybe $300 for machining the axle alone. Total cost - still less than a Mavic Cosmic Carbone road wheelset - for the lightest fixed wheelset around. We like that. See 'em at the Symposium.
So, there you go. Tired of regular threaded cogs? Try the LeVel, the Miche Carrier, or tackle a project like this one. We'll be doing a follow-up on this project in a few months when we find out how it holds up - swing back this way.
Contributors to this article include:
Velocity USA - Grand Rapids, MI