I've been using the Pathfinder Pro 38's for about a year now and I'm very happy with them. I live in an area where I have to ride asphalt to get to gravel and the Pathfinders are a great compromise - reasonably fast on the road and pretty capable off-road. A lot of the "gravel" around me is borderline XC mountain biking and they've performed pretty well on some technical stuff. Not the grippiest tires on loose or rooty climbs but it's a fair trade for solid road performance.

Can't speak to the Challenges.

I've just ordered a Cannondale Topstone that comes with a tyre on the rear that may be what your after. I'm away for work and my bike is sitting in the shop so haven't ridden it but may be worth considering they review well.

https://www.wtb.com/...el-cx/products/byway

Even though it has "knobs" in the center, I'd suggest the Continental Terra Speed.

Although listed as 40C, it actually measures more like 38mm, even on wide-ish rims, and rolls faster on hardpack and pavement than pretty much EVERY tire with a smooth, or file center and side tread, with the exception of the Challenge Gravel Grinder Pro (w/latex tubes) and the Challenge Gravel Grinder HTLR (Handmade, Tubeless Ready) which are both 36C, but are only 1W faster per pair of tires at 30kph. That said, those 2 Challenge tires are nearly 2X the cost of the Terra Speeds. The Terra Speeds are a MUCH better tire in the dirt overall IMHO, too. Think of it this way...you get a tire that rolls as fast as a "smooth" Rene Herse (Compass) Snoqualmie Pass 44C (regular casing) on the pavement, yet has great knob coverage for not only cornering off-road, but braking and traction too. It's hard not to like that combo.

If the Gravel Grinder you mention above is the TLR model, that's significantly slower than the tires I mention in the paragraph above, at ~6W per pair slower at 30kph on pavement.

I've no idea about the Pathfinders...but I haven't heard of anyone saying they're exceptionally fast.

All info found here: https://bikeblather.blogspot.com/...ravel-tire-list.html
and here: https://bikeblather.blogspot.com/...some-gravel-fun.html

---

http://bikeblather.blogspot.com/

Tom,

If you say it, I believe it! Think you just sold me. Thanks!

And yes I should have checked your site first. I was thinking about it before dinner and posted before I had time to check out what you’ve done.

Those designs make zero sense to me. At the lower pressures tubeless gravel tires are running, the entire tread surface is always flattened onto the ground. To truly have only the center 10mm touching when going straight, you'd have to be at a crazy high tire pressure. (Or be very light, I guess. I'm thinking about it as an 180 lb rider.)

So for that reason, better to look at the overall package as Tom A says.

True. I designated the path to the outcome. But really what I want is a fast tire that also grips well. Knobs, blobs or spikes... I don’t really care.

I also lied above. Wife has sawtooth. I have tracer pro’s. I’ve really been impressed with those tires but feel the bike kick out a bit more than I’d like in corners and thus wanted to try something different.

Well...to be fair, I really like the Challenge Gravel Grinder HTLRs too. I don't find the side knobs to be too obtrusive on pavement, and they actually corner on fast, paved turns surprisingly well. The file tread in the center actually works quite well off-road when new, and like you say, the side treads do come into play in the contact patch for a bit more straight-line traction.

I just wish they'd make them bigger than 36s...oh, and drop the price ;-)

---

http://bikeblather.blogspot.com/

I don't have them, but one of my good friends who rides a lot of gravel swears by WTB Byways. Smooth down the middle, knobby on the side. Bonus is they come in 650b and 700 sizes

IRC tires makes the Boken Plus too that fits that bill.

I have been loving life on 40c Terra Speeds this year after using a dozen different tires. They measure 40.0 mm on i23 rims around 30-35 psi once broken in.

I thought the Riddlers gripped quite well, but am not sure if they roll real fast. The 37 measured 38 or 39 mm on those same rims.

I have never really understood the smooth center strip type tires since they need too much pressure to keep you on that center strip.

The HTLR is also really difficult to find in the US right now and as you mentioned ridiculously expensive.

Thanks! Ordered a set last night. I’m running 43 measured now and don’t have any issues with clearance even with some clay buildup but our clay isn’t that super thick clay which is why I thought 38 would be good. Measured 40 will work too.

I had a pair of 650B Byways as the first tires on a set of 650B wheels I bought to try out that size...my first impressions were that they felt "sluggish" on the road, and the small knobs on the sides didn't do much in the dirt.

Roller testing confirmed they are ~10W per pair slower (@30kph) on hard surfaces than the tires tested above.

Want to buy mine? ;-)

---

http://bikeblather.blogspot.com/

I switched to Terra Speeds back in Feb for racing. They are definitely fast. I wish they were a true 40c width, and i wish the 35c was an actual 35. The 35s measure around 33. My impression is that the tread wears quickly, so i only use them for racing and gravel KOM hunting in order to keep the miles off of them.

My old team sent me a set of the new Panaracer SS tires to test out. Somehow they tested faster than the slick gravelkings I've been training on, which also test faster than the SK gravelkings. They were only slightly slower than the Terra Speeds. Panaracer must have done something different with the casing or protection layer. I'm not sure how they will wear, but typically the panaracer tires wear well.

A smooth tire with side knobs? Yes, I think that would be the perfect tire, but I don't think anyone makes it yet in a wide enough tire for me. I want a GP5000 in tubeless at 55mm wide with the side knobs of a Conti Raceking. For now I just use a Raceking that is worn down to smooth in the center (rear tire).

I use either a Byway in the front or a Schwalbe Thunderburt. I prefer the TB because it rolls the same (via my road pm testing) and has more float and traction, but it won't fit in one of my forks. As Tom said above, the Byway is not particularly fast, more like a fast mtb tire than a fast tire for the road, imo because there is a ton of rubber down that center tread. I run it tubeless, but rarely ever see the telltale signs of punctures that have been sealed by the sealant. I ran over three goatheads a few days ago and they did not even penetrate the middle tread.

And I would disagree with a post-er above; I run my tires at 20-25 psi and after leave the super fine dust I encounter in the summer and head back onto the road, you can see where the dust has worn off the center and not the side. I think a tire like you describe and I have mentioned in other posts before would be perfect for my use. Other than than I need 50-60 mm width for float in the summer sand. Here's to hoping Conti keeps making larger and larger Conti GP 5000tl in future years (especially a 650bx47 version).

I am very interested in the new GK SS (semi slick) tires.
I can not tell from your post if you tested them yourself or are simply privy to some test results. Either way I'd appreciate any info you can give.
I like my current 38mm GK SKs and have tossed around the idea of replacing them if they ever wear out with either 43mm SKs or 38mm GK Slicks. But the new SS GKs come in 43mm AND should roll faster than the SKs which makes them a potential Goldilocks tire for me.
Thanks.

i tested using my very unscientific test that would make Tom A cringe.

Get tires up to temp on my rollers, then hit the 50x11 at 77rpm, hit lap, ride steady at that cadence for 2 minutes and look at avg wattage.

Although unscientific, it has been repeatable and the tires fall in the same order from fastest to slowest as i've seen in Tom's chart and at bicyclerollingresistance.com.

I won't claim to know exactly how many watts different the Terras are from the GK SS, but i will say they were pretty close and faster than my blue GK Slicks and any GK SK i've tested.

They are also much quieter on the rollers than the conti. Maybe it's a dangerous assumption, but my guess is the conti casing is faster than the panaracer, but on a hard surface like a roller, the tread of the conti is less efficient (and therefore louder). Maybe on dirt the conti would see a bit more of an advantage over these other tires vs on roads or other hard surfaces.

Thanks. I'm now even more interested in the GK semi slicks. Dave K

I'm not cringing at all! That's a great way to at least evaluate relative differences.

---

http://bikeblather.blogspot.com/

Terra Speeds have been great combination of on-road stability, off-road grip, and low rolling resistance. They do seem to wear out relatively quickly.

I'm more and more convinced that semi-slicks (e.g. Challenge Gravel Grinder) are not worthwhile for gravel riding. Tire designs like this lack traction when the tire is upright, tend to feel "loose" when moderately leaned over, and grip moderately well when leaned further over. In my experience, most gravel turns are fairly shallow and thus you never lean enough to get the full grip from the side-knobs. Therefore, more uniform knobs across the crown of the tire are beneficial in gravel. This is in contrast to mountain biking where you can corner more aggressively and engage the side knobs with more authority.

When outright rolling resistance matters most, go with a fast slick. E.g. primarily road with less / non-technical dirt.
For general gravel / non technical singletrack, with an emphasis on speed, go with the Conti Terra Speed,
For rowdy gravel, go with whatever tread gives you confidence and consider rolling resistance second.

---

I talk a lot - Give it a listen: http://www.fasttalklabs.com/category/fast-talk
I also give Training Advice via http://www.ForeverEndurance.com

The above poster has eschewed traditional employment and is currently undertaking the ill-conceived task of launching his own hardgoods company. Statements are not made on behalf of nor reflective of anything in any manner... unless they're good, then they count.
http://www.AGNCYINNOVATION.com

I'd generally agree with that...BUT, if it wasn't for the Terra Speed, then my choice for the 2nd category you list above would be the Gravel Grinder (Pro, or HTLR).

I find that at appropriately low pressures, the side knobs are still somewhat engaged on the flat and in light cornering. One ride back-to-back with that tire and a perfectly smooth tire on the same terrain shows that they are doing something. I've (painfully) experienced the difference at times when using a "slick" in those "general gravel/non technical singletrack" conditions ;-)

---

http://bikeblather.blogspot.com/

WTB Nano works great for multi-surface rides. I run them in 40s on my gravel bike and have been very happy on everything from roads to rough and muddy singletrack.

60% of the time they work every time.

---

I talk a lot - Give it a listen: http://www.fasttalklabs.com/category/fast-talk
I also give Training Advice via http://www.ForeverEndurance.com

The above poster has eschewed traditional employment and is currently undertaking the ill-conceived task of launching his own hardgoods company. Statements are not made on behalf of nor reflective of anything in any manner... unless they're good, then they count.
http://www.AGNCYINNOVATION.com

i agree with a lot of that.

One counter argument -- I think slick tires tend to be dangerous on ruts that run parallel with the road. Having a little side knob seems like it could help pull the tire out of the rut. Probably not a big deal on most courses, but on courses like Midsouth where sections are pretty rutted, it could mean the difference of finishing with your collarbones in tact vs not finishing at all.

other side note: I said my testing lined up with bicyclerollingrestistance.com. Well, i saw they recently did the GK slick and had it the same as the terra speed. When i tested, the terra speed was faster on my rollers. Maybe they changed the casing on all the GKs and not just the SS? I don't know