Wider bars, wider rims, wider tires… there’s no question that many gravel bikes are quickly evolving into more capable machines. But get too aggressive on the typical light weight gravel tire and you may be left trail-side plugging holes. Or worse. Naturally, manufacturers are looking for ways to create more durable gravel tires, but in a way that doesn’t leave you with two round boat anchors. WTB just released their answer to the issue – their new SG2 puncture protection.
While the goal of creating a more puncture proof tire was always WTB’s goal, the way they have gone about it has changed drastically during the casing’s development. Originally, WTB tried to add puncture protection in just the side wall with their existing Slash Guard tech. This used a nylon insert that covered the entire sidewall, but since it was originally developed for enduro MTB tires, it was a thick insert and ended up too heavy. WTB still wanted that same level of protection but at a minimal weight, since most gravel riders put a higher emphasis on weight.
The solution turned out to be a thinner nylon insert compared to Slash Guard, but one that wraps around the full tire from bead to bead called SG2 (Slash Guard 2). To make it lighter still, WTB utilized flat nylon fibers instead of round. This doesn’t make much difference in the weight of the nylon, but it results in less rubber needed between the fibers which results in a lower overall weight. Not only does the nylon insert make the tire more durable, but WTB notes that an added benefit is increased air retention in tubeless set ups as well.
Previously, all of WTB’s gravel tires were 60tpi. That was due to the fact that they weren’t able to get the desired durability previously with 120tpi casing without doubling up. However, in their testing with 120tpi casings combined with SG2, this made for the protective tire they were looking for, without losing ride feel, and adding minimal weight. With the new tires, WTB is claiming just a 5-10% heavier tire than their previous 60 tpi tires, but with 17% more tread protection and 33% more sidewall protection.
For now, you’ll only find WTB SG2 casings on gravel tires that are larger than 37mm, and in black sidewalls only. Why not tan wall? It turns out that the compounds needed to make tan wall tires are just slightly less durable than black wall. So in an effort to keep SKU counts down, WTB figured if someone wants the SG2 tires since they’re more durable, they might as well make them out of the most durable compounds – black it is. Along those same lines, larger volume tires are more likely to be run at lower pressures, which is why you’ll only find SG2 on 37mm widths and up.
However, all of the black and tan wall options in their non-SG2, 60tpi tires will continue to be offered. These existing tires will continue to be priced at $59.95, while all protected 120tpi tires have an MSRP of $69.95.
Prior to the launch, WTB sent over a selection of the new SG2 tires in various tread patterns. In the box were three pairs of tires – the WTB Raddler 700c x 44mm, WTB Nano in a 700c x 40mm, and a set of 700c x 40mm Byways. Naturally, I reached for the Raddlers first.
On the scale, the tires seem to live up to WTB’s claims with a 700c x 44mm SG2 Raddler coming in at 551g. Compare that to the 700c x 40mm black wall Raddler at 531g, and it seems that the 5-10% heavier claim could certainly be true – especially considering that the SG2 tire in this case is actually wider.
One note is the weight discrepancy between the two Byways. While the other tire pairs were within +/- 5g, the two Byway tires were 28g different. When asked for comment, WTB said that these were within a required tolerance of 10% stating, “in the end, tires are essentially hand built and therefore the human factor of production can cause variance. The amount of material on a building drum is hand cut with scissors and therefore a cut only a few centimeters one way or the other can cause a drastic difference in weight.”
Getting these tires onto the rim was no more difficult than a 60tpi WTB gravel tire, and they seemed to snap into place and seat with little effort. It did take a couple of rides and a bit of the ol’ sideways shimmy with the wheel to get a few pinhole leaks to seal. But after the second ride, they seemed to be fully sealed with Stan’s and air tight.
Mounted to the American Classic rims that came stock on the Lauf True Grit, the 44mm Raddlers measured exactly 44mm wide with minimal stretching after the first two weeks. Like the original Raddler, the Raddler SG2 still has a more squared profile than the Ridder with aggressive side knobs and deeper center tread.
When it came to the first rides on the SG2 tires, to me there was a notable difference in ride feel with sort of a smoother, more damped ride quality. In a way they feel similar to more protective mountain bike tires in that they feel a little more stout and seem to encourage riding with a lower tire pressure. If you read the sidewall, the tires state that they should be ridden at 30-60 psi. I started the ride with 35psi in both tires which I figured would be a little high. It turns out it was definitely too high, so I let some out on the trail until I got to a comfortable pressure. I ended up around 27/28 psi, which is obviously less than the tires recommend, but I had no issues running at these pressures. The tires certainly allow me to run a lower pressure than I would with a typical gravel casing.
For riders looking for the absolute lightest tire, these probably aren’t it. But for those who don’t want to risk a flat ruining their (race) day, the new SG2 tires seem like they deliver on the drastically improved protection with minimal weight penalty claim.