Soma Vitesse Tire Review from Velo De Route of France

We don't re-post reviews of our products too much here anymore, but since this one requires Google Translate and has such pretty pictures, we made an exception. View the full review here.
Joly reviewed the 42mm wide SL with an inner tube. He was interested in trying the tire after meeting us at Eurobike.

On the tarmac he had nothing out of the ordinary to report, but for the downhill...
<<In downhill the balance is strangely more mixed: admittedly, the section and the gum of quality offer a grip in curve, as braking, simply phenomenal, but the height of the bike does not fully exploit these assets. It is not the fault of the tire, but if you add the two centimeters due to the cyclo-cross frame and the tire, it is at least three centimeters higher than on a road frame in tire of 25/28 Mm. It starts to do ... In practice, the configuration photographed did not allow me to beat or even approach my reference time in downhill (established with Compass tires).>>

He noted his 42mm measured closer to 37mm. This was with a narrowish rim with 18mm internal width.
A 23mm internal width rim should get you closer to 42mm.

On gravel performance:
<On roads generally traveled in tires of the same volume but more or less clinging, with rubber flank, the difference of flexibility and yield is really impressive. The surface adheres very well, even on loose ground, and slightly damp, the grip remains very correct. The micro-slats that partially cover the surface of the tire are probably for something, and the adhesion is not less than with semi-slicks type "tip of diamond". In the mud ... it slips, normal. This is the obvious limit of a slick tire.
[On downhill gravel:]
There, it is a new (good) surprise. Once again the flexibility of the tire, and the absence of crampons [knobs] provide much less vibration than my usual tires. If it's obvious on the tar, it's also noticeable on a path. It seems that at equal volume, the absence of crampons provides better contact with the ground.>>

After a few tests I adopted pressures of 3 bars at the rear, 2.5 at the front whatever the ground, and so far without puncture. The lightness of the flanks is reminiscent of the first MTB tires of yesteryear, and therefore the specter of the pinch is very present in mind ... caution remains, but after 200 km of rustic gravel,

<
In the end, these Soma Speed ​​42 mm are the ideal gravel tires for dry conditions.
Their road performances are impeccable, and allow to drive in a group at high speed, as much as on a 150km turn.
But especially their performances along the way are really excellent. The combination of a large volume on a slick tire in my opinion provide the best versatility of a "gravel". Of course some extreme terrain or wet conditions require crampons, but always to the detriment of versatility and performance.>>

The writer makes an interesting note that tires in the 40mm and up range raise the BB of road bikes and CX bikes higher than what they are designed for. And thus you can't corner and steer as confidently, even with the added grip of these tires. Frame makers would need to make frames with lower bottom brackets. This isn't lost on us. We stay pretty conservative on our BB heights. Because ven though we are designing many of our bike to fit 38c and up, we have many customers and bike shops who will outfit our frames with 700x28.  This means we can't optimize the BB drop just for the largest tire size, because then the BB height will be too low for more common size tires. For folks wanting wider tires AND the lowest BB height with disc road/CX bike, your main option is to go with a 650b conversion. Second option...a custom frame.