Replaced a well used Continental GP4000sII with this tire and so far so good. While both tires were nominally 25mm, the GP4000sII mounted on my HED Belgium C2 rim (18mm inside width) measured just over 27mm wide while the STX Inertia measured just over 25mm. I suppose with today's wider rims as the sizing standard, the Inertia is spot on for a 25mm. But if you're used to older tires' sizing, the Inertia is basically the same sizing as some 23mm tires I used to use, e.g. the Vittoria Rubino Pro III Slick. The Inertia 25mm is narrower than the more modern Vittoria Corsa G2.0 25mm tire I have on the front wheel, which measures over 26mm on the same model rim.
Ride quality has been good--I'm not noticing comfort issues with the slightly narrower rear tire with slightly higher pressure. I haven't ridden in the wet (and I don't intend do) so I can't comment on wet traction.
The Inertia exhibits tiny imperfections when spun, unlike the Conti and Vittoria tires I compared them to that look perfectly round, but I'm not noticing it while riding.
I'd rate it a good value when on super -duper sale , ok at regular sale price, look elsewhere at MSRP.
The 23mm size mounted on narrow 19mm outside width rims are accurately that wide at .9". The height is just under at .8" above the rim. The bike has 400mm chain stays, crank center to rear axle center, and these have .3" clearance to the seat tube. I figure that the 25mm size may have fit with a .2" clearance like the 25mm Gatorskins that came off, but returning to the original spec 23mm size is interestingly quick and smooth at 80psi carrying less than 160 pounds total bike and rider. Losing 190 grams of revolving weight compared to the Continental set was noticeable when accelerating up hillcrests.
New, they took a good bit of cleaning up. The release coat was generous and crusty. That's not such a bad thing after seeing the flat black buffed up with fine steel wool. They felt like ribbon when mounting. Repeatedly working the initial bead down into the rim bottom and around to the loose side helped the edge drop over by hand. The outline had minimal wobble and runout when inflated.
The long injection hairs are easy to pull and nick off. Logos wrap into the cornering tread. Big white SERFAS letters will act as chicken strips that scuff up in hard turns.
All in all, these are fun, underrated tires not having a big brand name. The technology seems to be there.
This is a good mid range tire at a good price. I couldn't ask for more.
I've tried several tires from this brand and have had terrible luck the flat. The weather crack after a few months handle terribly and fall apart. They're actually dangerous. I don't recommend them at all. I've tried these in the 25 mm and they were somewhat easier to mount to the rim but these are not good tires.
I've put about 1,000 miles on it and while it's been a solid performer I would say it is prone to punctures. I've had several with very small metal wire that I would have assumed would not penetrate the rubber.
With barely 200 miles on them.One tire side wall ripped and the the other one just kept getting flats.
I order a set of tires about month ago. I have put in around 300 miles on them. Average PSI is about 100. Rear tire wire bead started to crack and the front tire has a tear on the side wall.
I have over 3500 miles of paved road riding, without a flat tire, and on the rear wheel. The tire surface is getting a little flat now, so plan to change the tire within the next 500 miles
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