May 27th, 2010
By Emiliano Jordan
For 2010, Polish component manufacturer Soul Kozak has updated their hub designs. The release of these took much longer than expected – we had been waiting for our shipment for weeks, and I was wondering if we were ever going to see the new product. We’ve been fairly busy at Fair Wheel, and when the hubs finally arrived about a month ago, all we had time for was a quick inspection and weight check.
The initial impression was mild disappointment, as the weight for the set of road hubs had increased by about 30 grams. However, that disappointment quickly faded; the retail prices had decreased significantly and the slight aesthetic changes seemed to be an improvement as well. Ironically, these long-awaited hubs ended up sitting on a shelf for the next few weeks as I got caught up on other projects. This week I’ve had some spare time to crack open the new and old Soul Hubs and see what’s changed, which I’ve detailed below. Also, I’ve written an initial review and impression of the 2010 Soul hubs as built into a set of incredibly light and inexpensive clincher wheels.
First thing’s first: front hubs. They’ve kept the same basic design, with a slight weight increase of 9.8 grams. In examining the individual components, I’ve found that the weight increase is shared between the larger section bearings and increased axle diameter. These two improvements should help to increase the hub’s stiffness and durability, so I think the trade off is well worth the weight gain. Total weight for the 2010 front road hub is an impressive 59.7 grams.
Comparing the bearings side-by-side, you can see that the difference in size is fairly dramatic. The new 699 bearing may still be considered small by current standards, but I would guess that the durability is on par with the more common 6802 or 6803 sizes. The 699 is smaller in diameter than these standard bearings, but it is also a millimeter wider.
The new model’s axle diameter has increased from a straight 8.9 mm to 10.4 mm stepped down to 8.9 mm at the axle ends. Also, the axle is anodized black versus bare aluminum on the old axle. This little detail should help prevent corrosion in extreme situations. Along with the axle diameter increase, the hub shell itself is slightly larger at 19.4 mm from 18.0 mm.
The machine work on both the old and new hubs is really top-notch. The press fits on both the axle and hub shell feel really precise, and the bottom ends of the hub bore and axle seat are relieved to allow full accurate press of the bearings. A design such as this with shouldered axles requires accurate machining to allow proper alignment of bearing races. The hubs feel quite smooth out of the box, so it seems like Soul has done good work here.
Flange dimensions remain unchanged – spacing is still very wide to allow for laterally stiffer wheel builds. I did find that the spoke holes themselves had increased slightly in diameter from 2.35 to 2.5 mm – I’m assuming that the old hubs may have had some issues fitting thicker gauge spokes.
And now the real kicker for the new Soul front hub – a huge retail price drop from USD $175.00 to $95.00. I have no idea how this company managed to bring the price down so much, since there were no dramatic changes in design or materials. In fact, after examining the hubs closely, I would have expected the price to increase a small amount.
Soul-Kozak’s rear hub design has been tweaked quite a bit for the new model. As with the front hub, bearing size has increased, though the axle diameter remains the same. The 20 gram weight increase over the old model is due almost entirely to the use of larger section bearings. The flange dimensions have been changed quite dramatically to allow for easy freehub body conversion. These implemented design changes make the hub look a lot like a DT 240s – with the same bearing number and sizes and virtually identical flange spacing. Although I may question the reasoning behind some of the changes, taking some cues from one of the most prolific hub designs in modern cycling can’t be all bad. Total weight for the rear hub with a Campagnolo freehub body is 185.3 grams, and the Shimano version is 195.5 grams.
The 2010 hub uses two dramatically larger 6902 bearings in the main body, with dual 6802 bearings inside the freehub (the old design used three 6802 bearings and one 6803) Again, the rear hub machine work is excellent, and the bearing press fits feel just about perfect. I’d say that the axle fit is a little on the tight side, but with proper tools removal and installation is not a problem. The inner freehub bearing is retained with a spring clip that looks very difficult to remove, which isn’t a huge problem since that bearing is fairly protected from the elements and doesn’t wear too quickly.
It seems that a major design consideration for the 2010 rear hub was simple freehub interchangeability. This is reflected in the somewhat compromised flange spacing. The drive side flange has been moved inward .9 mm, which further increases dish in the wheel and difference in drive and non drive side spoke tensions. To compensate, the non drive flange is also moved inward a full 5 mm. Center to flange measurements are slightly wider than a DT 240s. Swapping freehub bodies is incredibly easy with the Soul hub… almost. If it weren’t for the tight axle fit, it would be possible to change the freehub in about 10 seconds with no tools. Changing back and forth from a Shimano or Campagnolo setup requires no wheel redishing and no specific axles or end caps. Fortunately, most cyclists don’t find themselves changing freehub bodies too often, so this is mostly an issue for bike shops and manufacturers. Surprisingly, the Campagnolo body is about 10 grams lighter than the Shimano body.
The freehub ratcheting system is simple and robust – three simultaneously engaging steel pawls on a deep steel drive ring. The shape of the pawls and the way they integrate with the spring is interesting, but fairly standard in basic design.
For 2010, the rear Soul hubs see a price drop from $395.00 to $300.00. Combined with the front hub’s weight and price, these hubs allow for sub-1400 gram wheel sets for under $600. I took this idea and ran with it - and built a (somewhat experimental) 1255 gram set. While these hubs may appeal to budget-minded cyclists looking to shave some weight, I believe the quality justifies their use on both high-end and inexpensive lightweight wheels.
I’ve put about 500 miles on a set of 2010 Soul Kozak hubs laced with DT Swiss Competition and Revolution spokes on Kinlin XR-200 rims. I’ll say first that I wouldn’t recommend this wheelset for most riders, and it’s something of an experiment. I’ve been told by other wheelbuilders that the 380 gram XR-200 rim is too fragile for low spoke count (20/24) wheels. I have a little more faith in this rim myself, and I wanted to see for myself just how long they would last under my 160 pound frame.
I’d say so far so good. I’ve been riding and commuting on this set for a few weeks now. My route to work isn’t exactly pothole free, but I haven’t really put these wheels through the rigors of some tough training rides either. I would suspect they’re a little flimsy for all out sprint efforts, but perfect for long slogs uphill. The hubs have been absolutely problem-free, and the front wheel is stiffer than I would have expected, which I would attribute to the wide flange spacing.