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by Matt Wikstrom
August 14, 2017
Photography by Matt Wikstrom
TECH NEWS BROUGHT TO YOU BY BIKEEXCHANGE
Stelbel is a renowned Italian brand that was founded in 1973. After almost 20 years of custom-building steel framesets, the workshop closed its doors in 1990. Now, the brand has been resurrected with the help of the original owner, essentially picking up where it left off to take advantage of the latest advances in steel tubing.
In this review, Australian tech editor Matt Wikstrom takes a look at the SB/03, a modern frame that honours Stelbel’s classic heritage.
Stelio Belletti was 13 years old when he started working in his father’s workshop. World War II had just come to an end and Antenore Belletti had parlayed his experience building aircraft fuselages to start up his own business. The workshop started supplying fuselages to local aircraft manufacturers before expanding to build motorcycle frames at the end of the ‘50s.
The fresh focus coincided with a move to a bigger workshop and the eventual purchase of TIG welding equipment. Antenore could see the potential for the relatively new technique, and as his father’s partner in the business, Stelio was soon trained in TIG welding.
In wasn’t until the early ‘70s that Stelio started thinking about bicycle frames. By this stage, he was 40 and his passion for the sport had been reignited. He had bought himself a racing bike and was competing in local events. It wasn’t long before he started pondering his equipment, at which point he was convinced he could build a better frame using TIG welding rather than traditional lugs.
At the time, Belletti understood the novelty of his efforts. First, he created Stelbel to start selling his frames in 1973 then he submitted a patent for his TIG-welded framesets to the Italian office in 1975. Stelio had his father’s full support and encouragement but it was a win by the Polish national team while riding Stelbel’s framesets in the men’s team time trial at the 1975 world championships that brought the new brand the kind of attention needed to grow into a profitable venture.
By the close of the ‘70s, the Belletti workshop was devoted to bicycle frame manufacture and Stelbel. Antenore retired from the business during the early ‘80s while Stelio continued welding frames until 1990 when the brand and the workshop closed its doors.
Stelio would continue to collaborate with local framebuilders but no more Stelbel frames would be built until Cicli Corsa resurrected the brand in 2013. The Italian-based distributor and online retailer started life in Germany reconditioning classic Italian road bikes, so it had a great appreciation for Stelbel and its heritage.
The endeavour was more than an exercise in nostalgia, though. Cicli Corsa was intent on reviving Stelio’s aesthetics and unique methods, but they also wanted to embrace and experiment with the latest technological developments in steel. To this end, they had a willing collaborator in the master framebuilder himself.
A new workshop was opened in the north of Italy and populated with craftsmen handpicked and trained by Stelio so as to satisfy his standards for every step of production. He also contributed to the design and technical details of the new frames and continues to visit the workshop at least once a month, often to discuss improvements for each frame.
Unsurprisingly, steel tubing and TIG welding remains at the core of the new Stelbel range. Every frame is made to measure, built to order, and truly Italian-made. In all, there are eight frames in the new catalogue: five for the road, two for the track, and one for gravel/cyclocross.
While some models, such as the Strada and Strada Super, honour Stelio’s classic designs, the Antenore, SB/03 and Rodano are distinctly modern bikes. What that means is oversized tubing, threadless headsets, and carbon forks. The candidate for this review, SB/03, takes this notion even further by incorporating a tapered head tube, internal cable routing, and the newest oversized threaded bottom bracket design, T47.
As a classic Italian brand, it’s not really surprising that Stelbel chooses to work exclusively with Columbus steel tubing. In the case of the SB/03, its a custom double- and triple-butted tubeset.
The head tube is the thickest in the frame, tapering from a diameter of 46mm at the top tube to 56mm at the down tube. The bottom half of the frame is also very thick with a down tube that has an outer diameter of 44mm while the chainstays are 36mm tall. In contrast, the top half of the frame is quite slender, mirroring what has become a common strategy for maximising the lateral stiffness of the frame while preserving an amount of compliance.
Continuing with the theme of oversized specifications, the SB/03 features a T47 bottom bracket shell. This relatively new design provides plenty of surface area for welding the oversized down tube and chainstays while preserving the dependability of a threaded bottom bracket. It also gives buyers the freedom to use cranks with a standard 24mm axle or an oversized 30mm axle.
Stelbel CNC-machines its own dropouts from stainless steel. Not only do they mate perfectly with the brand’s extra-tall chainstays, the material is very hard-wearing. Compared to the dropouts found on modern composite frames, Stelbel’s stainless dropouts appear wafer-thin yet they provide crisper shifting thanks to a non-replaceable derailleur hanger and the intrinsic strength of the material.
Each SB/03 is built to suit mechanical or electronic groupsets, or both, if desired. There are also versions to suit rim brakes (centre mount callipers, quick-release axles) and disc brakes (flat-mount callipers, 12mm thru-axles) and both will accommodate tyres up to 30mm wide.
As for the rest of the frame’s specifications, the head tube is machined for an integrated headset (1.125inch upper bearing; 1.5inch lower bearing), the seat tube accepts a 27.2mm seatpost, and there is a choice of a braze-on mount or a 28.6mm clamp for the front derailleur. A full-length rear brake cable is routed through the top tube (for rim brakes) while the gear cables are routed through the down tube.
Interestingly, short sections of outer housing are used to guide mechanical gear cables around, rather than through, the bottom bracket shell. It’s a decision that most mechanics will welcome, since it makes it easier to replace the cables. At the same time, any contamination by grit can be dealt with by simply replacing the housing.
Every joint of the SB/03 is TIG-welded then smooth-finished for a beadless finish. It’s a labour intensive process that honours Stelio’s original craftsmanship and provides a distinctive finishing touch to the frame. One tube seems to flow into the next, much like a fillet-brazed frame, however there is less bulk and the effect is more subtle.
TIG-welding is widely used in the bicycle industry today but back in the early ’70s, Stelio Belletti was a pioneer. Photo: Stelbel.
One of the unsung strengths of a handbuilt frame is the amount of attention that can be devoted to ensuring that it is striaght. Photo: Stelbel.
Once welding is completed, each seam is hand-filed to achieve a smooth finish. Photo: Stelbel.
Hand-filed welds were one of the hallmarks of Stelio Belletti’s original steel frames. Photo: Stelbel.
The SB/03 frame is mated to an all-carbon fork supplied by Columbus with a tapered steerer. The bold tapered legs perfectly match the width of the head tube, making for yet another seamless transition, and complements the muscular lines of the frame.
Every SB/03 is made to measure, so there is no standard geometry for buyers to choose from. Stelbel will design the geometry around the rider’s fit data or body dimensions, taking into account any preferences for the steering and handling of the bike, however buyers are free to provide as much input and direction as they desire.
The SB/03 is finished simply with a single colour of paint and a small contrasting logo on the down tube. The decision for each is left entirely in the hands of the buyer. The workshop can match almost any colour with options for pearl, metallic and pastel colours along with gloss or matte finishes. In addition, buyers can have a stem, seatpost and/or handlebars painted to match.
Branding is kept to a minimum, so at a distance, the bike is almost unidentifiable. It’s a classy aesthetic that some may overlook, but for those onlookers that take the time to approach the bike they will discover a variety of thoughtful touches. That includes the hand-smoothed welds and engraved logos on the head tube and bottom bracket shell.
I found that all of these small touches added to the beauty of the frameset and it seemed to get better-looking each time I stopped to take it in. Perhaps the most impressive triumph for the SB/03 is that it appears thoroughly modern while preserving the essence of a classic steel road bike, and perhaps more importantly, the brand’s heritage.
The SB/03 supplied for review was designed to suit my fit, though I left the decision on fork rake, bottom bracket height, and steering trail in the hands of Stelbel. The result was a semi-sloping frame with 70mm of bottom bracket drop and 410mm chainstays. A fork with 45mm of rake was matched to a head angle of 72.7° to provide 59mm of trail.
The frame weighed 1,870g without the headset and seatpost clamp while the fork weighed 350g with a compression plug and crown race. When built up as shown with Campagnolo’s Chorus groupset, Bora One 35 wheelset, Fizik cockpit and post, and a Brooks Cambium C13 saddle, the total weight of the bike was 8.44kg (without pedals or cages).
Pricing for a SB/03 rim brake frame with a Columbus fork starts at €2,100 (~AUD$3,100/US$2,450) (excluding VAT) while the disc brake version costs €2,340 (~AUD$3,450/US$2,730) (excluding VAT). In both instances, that price does not include a headset, seatpost clamp, or shipping.
As a bespoke framebuilder, Stelbel can accommodate all sorts of customisation and personalisation for an extra charge, be it modifications to the frame, a fork upgrade, or a complete bike. In every instance, buyers can place an order through one of Stelbel’s retailers or deal with the company directly. A 50% deposit is required to confirm the order, at which point Stelbel will start working on the design of the frame.
The lead time for Stelbel’s frames varies throughout the year, subject to demand and the supply of materials, but in general, it is roughly four months. All of Stelbel’s framesets are supplied with a general five-year warranty and there is a lifetime guarantee for the quality and integrity of the welding. For more information, visit Stelbel.
If it’s not clear from my comments above, I was enamoured with the SB/03 from the moment I lifted it out of its box. That sentiment only grew as I started to ride the bike, and by the end of the review period, it had escalated to something approaching intense devotion.
Such a deep and lasting impact is a little unusual, so how did Stelbel win my heart? Well, it wasn’t any one thing; it wasn’t even a few. Rather, it was the combination of every aspect of the bike that amounted to something greater than the sum total.
Perhaps the most important place to start with dissecting the performance of the SB/03 is with the rider’s pre-disposition. I came to road cycling in the ‘80s, a time when steel dominated the marketplace and the professional peloton. I would spend the next 20 years riding steel road bikes, so I think it’s fair to say that the material has some strong associations for me.
Those classic bikes had their problems though, primary of which was the reed-like tubing used for construction. Some riders would get frustrated with the amount of flex around the bottom bracket, but for me, it was torsion at the head tube. It undermined the steering and handling of the bike and contributed to a general sense of flimsiness.
In the time since then, steel alloys have improved and tubing diameters have grown, as illustrated by the SB/03. The result is a stout bike that lives up to modern expectations while retaining that “real” feel of steel.
That’s not to say that the SB/03 directly rivals its carbon fibre contemporaries. Steel doesn’t have the benefit of the same kind of strength or stiffness to weight ratio, so it weighs the bike down a little. As a result, the SB/03 never felt as spritely or nimble and it couldn’t deliver the same kind of snap as a lightweight composite creation.
When judged by this sort of criteria, steel may be lacking, but there are still some very good reasons to be using the material today, as the SB/03 ably demonstrated. Principal among those is the mellow ride quality that can be achieved with it. This may be a nuance that can only be appreciated by connoisseurs, but it is quite distinct, and in this reviewer’s experience, extraordinarily pleasing.
The SB/03 had the ability to smooth out vibrations arising from the road without doing away with them altogether. In fact, the bike often felt like a natural extension of my body, alive with sensation like a healthy limb. I know some riders would rather be completely insulated from any kind of feedback from the road, but in its absence, I always end up feeling disconnected from the bike.
I tackled all sorts of paved and unpaved roads with the SB/03, and in every instance, I enjoyed a smooth, velvety ride with just enough sensation for me to read and understand the terrain. Any less, and the bike might have felt numb and sterile; any more, and there would have been a risk of it overwhelming the senses.
Swapping between different wheels and tyres influenced the threshold at which the SB/03 started reporting on the terrain. When fitted with 27C tyres, the carbon Bora One wheelset acted to damp a lot of the sensation; swapping to narrower tyres brought some of the colour back, while a switch to a low-profile alloy wheels proved to be the most satisfying.
The alloy wheelset also added to dulcet tones of the frame. The SB/03 could ring like a fine instrument and I could lose myself in the melody travelling through the bike. By contrast, a composite frame cannot manage the same feat: all that any rider can expect is something of a hum.
The steering and handling of the SB/03 were perfectly pitched to accompany the rest of the bike. Steady and stable at speed, I had the freedom to change direction and corner as aggressively as I pleased. I would have preferred a lower bottom bracket so that I could swing the bike around and hang off it with a little more abandon, but it wasn’t something that undermined the performance of the bike.
One measure of a great bike is that it performs and meets the expectations of the rider so well that he or she stops noticing the bike altogether. I attained this state after a couple of weeks on the SB/03, and in retrospect, it defined my experience with the bike.
My satisfaction with the SB/03 was so great that it raised questions about the true importance of highly prized traits of a bike, like bottom bracket stiffness, climbing prowess, and the overall weight of the bike. As mentioned above, my first impressions of these things may not have been very strong for the SB/03, but as time passed and my appreciation for the bike deepened, they ceased to be important.
My enjoyment of the bike was no doubt helped by the fact that the SB/03 had been made to measure to suit my fit. This is not something that I would normally discuss for any bike, such is its subjectivity, but I think it’s worth acknowledging it in this instance. In strict terms, a millimetre-perfect fit may not elevate the performance of the bike per se, but I’m sure it encourages the rider’s connection with it.
A steel bike does not necessarily demand an opulent build because the material is so modest. In this regard, Campagnolo’s Chorus groupset was a perfect match for the SB/03; likewise, Fizik’s alloy cockpit and seatpost. And as I’ve discussed above, there’s no need for a set of flashy carbon wheels; pick a good set of alloys instead and use the tyres to fine-tune the ride quality of the bike. Stelbel have provided a lot of tyre clearance (up to 30mm) so buyers have a lot of room to play with.
It wasn’t so long ago that steel was going through a massive slump. After decades of dominating the bicycle industry, demand for the tubing suddenly dropped at the turn of the century, as first aluminium, and then carbon fibre became the material of choice for building race bikes.
That trend has been reversed in recent years, though steel is still a long way from returning to its former supremacy. Nevertheless, it has regained some of that vigour thanks to fresh innovations in materials and tubing. In short, steel has managed to move with the times and the results are spectacular.
Stelbel’s SB/03 has a lot in common with the other modern steel bikes that I’ve reviewed recently, namely Bixxis’ Prima and Jaegher’s Interceptor. All three frames are custom-built using Columbus tubing and TIG-welding, and all three managed to ignite my enthusiasm.
While this may simply be a reflection of my bias and enthusiasm for the material, I remain convinced that there is a place for steel in today’s marketplace. I don’t expect the SB/03 (or any other steel bike) will satisfy the needs of all buyers, but it has something distinctive to offer that can’t be found with composites. And when that is combined with a one-off customised frameset, the results are spectacular.