Someone actually put the 50 mm G One RX Pros in the mail to me yesterday!
(Right after doing a 13 hour Unbound 200 on them so they are broken in well, haha.)
45 mm RS Pro might be a good one?
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In a bike check video I saw with Hannah Otto for Unbound she basically mentioned that she was running like aā¦ 45? Or something like that and her stance seemed that some of the big tire movement was a bit overrated and not as fast..
I feel like thatās a sponsor statement considering she had major performance losses at sea otter because her tire was rubbing the frame and causing issues.. Of course sheās going to say something like that as opposed to, āI want to run big tires but canāt because my frame.ā
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Thatās a narrative coming from several pro riders right now (including Keegan and Alexey). I donāt know how much of that is real, sponsor directed, or maybe just trying to convince themselves when they donāt have the option, but itās out there. And while I totally agree that a MTB-sized tire isnāt ideal for all gravel races for all riders, I am convinced that there are many situations where a MTB tire is the best choice. The only real downside I see to a frame that supports wide tires is the lack of support for 2x drivetrain. And as long as the big OEMās have to keep Shimano on their good side (or Shimano finally embraces 1x for road/gravel), itās going to be a slow move to 57mm tire clearance in the rear. I think the only brands making a frame that supports 57 in the rear are the brands small enough to not care about pissing on Shimano. And 2 of those brands (Lauf and Allied) donāt even embrace the SRAM XPLR gravel group and spec most of their bikes with MTB transmission groups. Nice to be a small brand that can do what makes sense rather than bend to industry dynamics/politics.
I was looking at bikes pretty closely at Unbound this year, particularly at the start line and the first 40 miles when I was in the lead group (before I flatted). Lots of big tires being run, some on Laufs and Ables, many just squeezed into frames they have no business being in. It likely would have been way more if not for the risk of mud. I was particularly surprised by the number of new Alliedās I saw. Not that many on pure numbers, but weāre talking about a $4500+ frame (and very expensive builds) that launched less than 2 months ago. So, clearly a decent percentage of serious amateurs believe in the advantage of running larger tires and I assume the bike companies are seeing this and trying to figure out a path for when these folks buy their next frame/bike.
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Realized I basically just reiterated what I posted earlier about wider tires on the 100 mile course 
Especially from someone like Keegan - he has the watts and the skillset to be there at the end, so I could see him thinking that he needed to choose the best tire for a bunch sprint while being durable enough to get there. Wasnāt the way it worked out, but I could see it for him.
For people like DJ who doesnāt have quite that power, and all us mere mortals, itās either more of a TT effort or needing all the help we can get to just be there at the end.
One of the reasons why I donāt think advice from people like Keegan and Alexey necessarily applies to us. And anyone whose bike wonāt fit large enough tires in the conditions on a specific course I definitely donāt trust.
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Yes, but Karolina Migonill (first place women) ran a 2.1 Thunderburt up front, and second place woman ran Thunderburts front and back.
Also we need to take into account that us amateurs likely need a larger tyre than smaller/lighter pros. I must have 30 to 40 kgs more weight than Karolina Migonill. Matt Beers would very likely benefit from a 2.2 tyre.
Maybe tyre size should be proportional to weight. I remember doing some basic science for a wheelchair company on vibration affects. I basically drove a powered wheelchair (to keep power and speed the same as I was not skilled enough to do that with my arms) with an IMU on skinny tyres, then bigger tyres and then suspension based wheels and it was a massive difference when you are sat in the chair with no leg or arm support.
The true answer for gravel bikes may be a lightweight, efficient suspension system with a fast slimmer gravel tyre similar to Rob Brittonās set up (xl winner).
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They both have frames that can run MTB tires and have in the past on many occasions. Thatās different than Hannah who has a frame that canāt even fit the tires.
The only conflict I see with Keegan is that he has a specific tire sponsor that has released a new tire line that Iām sure they want to promote, and that line of tires isnāt mtb sized. Isnāt the new maxxis line limited to 45mm? Canāt recall.
50, Keegan ran 50ās at Unbound. He says it in the cooldown video. And yes, I think he needs to promote all the new tires Maxxis just came out with, absolutely. Just like all the Specialized racers HAD to ride the new Diverge with 50 tracers. I just canāt imagine they would all land on the same bike/tire combo unless it was mandated.
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They both have bikes that can squeeze in MTB tires on a day where mud clearance isnāt an issue. Neither of those bikes are rated to properly support MTB tires (front or rear). Big difference between making it work and designed to work that way. Keegan also ran a 40 (or maybe 42) chainring on his MTB at a race last year. He had to offset the crank to the right and it was still grinding into the chainstay at times. Iām all for making things work and hacking together solutions, but prefer to work within intended design limits when possible.
I ran a MTB tire on the front of my checkpoint most of the season without issue, until I ran into conditions where it was an issue. Itās just not designed for tires that big. Lots of folks went smaller this year at Unbound due to the mud risk, not because they believed smaller was faster. Keegan switched from his suspension fork to a rigid fork specifically for more clearance in case of mud, not because he believed it was faster.
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Iām pretty sure he ran 50 ramblers (not a new Maxxis tire). Durable, but about as slow rolling as they come. He almost certainly would have rolled an Aspen ST over a rambler 50 if not for the mud risk. The new gravel tire from Maxxis is the Reaver (which I think tested pretty decent), but it only goes up to a 45mm at this time. Maxxis have said a 50 is coming (since every other tire company is talking about their 50ās), but Maxxis is behind the curve. Iām sure Maxxis would have liked Keegan to run the Reaver, but I think Keegan has the juice to make his own tire selection based on what he thinks is best. Unfortunately, his choices are limited to Maxxis.
Isnāt that Rambler a new version of the rambler though? I thought I heard they had re-done it kinda like how Spesh has new pathfinders? I could def be wrong because I wouldnāt even consider a rambler.
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I didnāt think about that. Looks like it is same tread pattern, but they have recently updated the compound. Not a full update like the pathfinder, but maybe itās better/faster than the old one (a low bar). Havenāt seen it tested.
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Keegan was talking about a new Maxxis Gravel Tire and compound that was testing really fast on the podcast he did with Jonathan pre-Unbound. Not sure if thatās what he ended up running though.
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I would like to see more aero data for gravel suspension forks. As far as I can see we have nothing for telescoping forks (only Lauf?) right now and given the speeds under discussion this is going to be a major factor in determining the comfort/suspension, rolling resistance, aero matrix.
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She also punctured and managed to nurse it to the finish.
Menās winner rode 45/50 schwalbe R series and as far as I am aware had no issues.
Lots of selective hearing here. Itās wrong to ignore the science when it comes to pure RR speed, but the title of this thread also includes āthe bestā and that covers far more aspects than just speed.
Itās quite possible that many of the pros that have gone for narrower tyres have done so for other reasons than RR speed.
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This one might throw some folks for a loop.
Race King Pure Grip 29 x 2.0 outdoor Chung Method testing RESULTS.
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Since I have a Checkpoint, Iād be curious to hear where you found the actual (vs published) limit to be.
On a gen2 checkpoint, I believe the published limit is 45mm. On a dry day, I have no issues running a 2.2 Race King in the front (measures ~56), Itās a no go in the back with a 2.2 RK, it sort of fits, but knobs rub on the drive side chainstay. I know some people have talked about dishing the wheel over a bit and shaving the knobs, so maybe thatās an option but I never tried. A 50 fits fine in the rear when dry and you could probably push a little bigger depending on the tire. So, thatās whatās possible under ideal circumstances. It just doesnāt work in the mud and you might get the random rock sucked/wedged between the tire and frame.
With mud, it just depends on the type of mud and how much you care about your frame. I ran 42ās front and back at Unbound in '23 due to the mud risk and still had some nasty rubbing (scraping of fork and chainstays), but it probably did better than most setups that were out there. So, even being under the rated limit of 45, you can still have issues. But 47ās would have been a disaster in '23 and I would have been walking a bunch. For typical (not super sticky) mud conditions, Iād say a 47 is a relatively safe tire for the checkpoint, particularly if you arenāt particular about scratching up your frame a bit (itās a gravel bike, so itās gonna happen anyway). That is what Iāve been running for the majority of races over the last 3 years. Enough clearance for a little mud, but still a risk of scraping and just a bit beyond the rated tire limit. And also keep in mind that tire sizes vary by brand and rim width mattes also. My go-to tires have mostly been pathfinders. A 47 pathfinder pro on my 25mm internal rims measures 48 wide.
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Trey from the Bicycle Station posted his Unbound 200 recap video and it was pretty concerning all the punctures he got using the Dubnitalās. He was running them on Reserve wheels, which he also cracked to end his day.
