Review: WTB Course & Byway Aero Gravel Tires

Note: WTB sent over a pair of the 700 x 50mm Byway tires and a pair of the 700 x 52mm Course tires for test and review. Guitar Ted Productions was neither paid or bribed for this review. All thoughts and opinions are Guitar Ted's. 

The new aerodynamic, wide gravel tires from WTB were introduced last week. If you missed the introduction, you can go back and find it HERE. 

In this article I will break down the Byway and Course tires with impressions, how they mounted up, and I will give weights and measurements as well. 

Side Note: I did not request the widest tire introduced, the Macro, as I did not believe it would fit any of my gravel bikes. (Maybe I should have though. I'll explain later)

Why Aero?

Okay, so "aero gravel tires". What is up with that? In some ways it may seem silly. However; we are seeing wider road tires which take aero into consideration, and gravel tires are even wider. Aerodynamics do come into play and can be leveraged to benefit faster paced gravel riders. Wheels are starting to catch up with all the aero focus as well, so we may well see systemic approaches with tires and wheels mated for best performance attributes soon enough. All this to say that, while you may not care, aero matters. Best get used to it. 

WTB went to Sromm Cycles for research and development on these new gravel tires. They came up with what is called "trip strips" and "vortex generators". These are characteristics molded into the tire casing which break up the air flowing over the tire and which help reduce drag. Drag is bad. Less drag, less work to maintain a speed. (Again- See my introduction piece for details.)  

So, that is one big deal with these new tires, certainly. However; it will be something I will have a hard time demonstrating. It is my belief that this is something you can do only in a wind tunnel where drag and aerodynamic characteristics can be verified. Guitar Ted Productions does not have access to one of these facilities. So...  I'll just be taking Stromm's word on that, and I will focus on ride quality and other aspects of these tires. 

The Course:

This model is the 'all - arounder' in the three tire range. It has a compact pattern of low knobs concentrated on the central portion of the casing. These tread blocks become more sparse and wider spaced as you move to the casings shoulders. The outermost feature on the casing which looks like little "v" shaped tread blocks are actually the vortex generators. 

This tire and the Byway also feature the SG2 bead-to-bead puncture protection belt. Not only does this help prevent punctures and tears, but because the weave of the material is tighter, it also enhances air retention. 

The Byway:

You might recall "Byway" as a model name used by WTB before in its Road Plus line up. This new Byway is only similar in its name. The tread pattern is completely different. Add in the aero features and there is really no comparison to the old Byway. 

This new Byway is the all-out speed tire with minimal tread and a slick center section which would lead one to believe it also has the lowest rolling resistance of the trio of new tires. Like the other tires, the Byway has a 120TPI casing, Dual DNA rubber, and the SG2 belt discussed above. 

The Byway is the narrowest tire at 50mm claimed while the Course is claimed to be a 52mm tire. WTB recommends these be mounted on rims with inner rim widths of 25mm - 30mm. Recommended air pressures range from 25psi to 45psi. Both tires I received have the tan sidewalls, but black sidewalls are also an option. Of course, these are tubeless ready tires and they require sealant to be used tubeless, but you could also run tubes if you so desire. (But this more than likely would not be optimal from a benefit/performance aspect)

It is notable that - for now - there are no other widths available than the ones introduced and there are no 650B sizes available. Also notable: I searched the WTB site to see if these tires are recommended for hookless rims, but I could find no such recommendation on the pages for these models, in the Tire User manuals, or in the Rim User manuals. So....if you have hookless rims, you may want to contact WTB directly to clear this with them. 

Weights, Mounting, First Impressions:

WTB claims the Byway weighs approximately 620 grams. The Course is claimed to weigh approximately 635 grams. My samples weighed as follows: Byway - 592gm/598gm and Course - 634gm/625gm. 

The mounting procedure was a bit of a mixed bag experience. I used the Course on my WTB CGR i23 wheels. Yes.....2mm narrower than recommended. But my reasoning was these are matching brands. So, I went with those. It is a system with both rims and tires coming from WTB. The Byway tires went on a set of Irwin carbon rimmed wheels with an inner rim width of 25mm.  

One of the Course tires went on with no tools, fit snugly, and aired up with my SILCA floor pump without removing the valve core. Nice! However; the next Course tire required much more work. I had to lever the tire on, first of all. There was no way it was going on without a lever. In fact, both Byway tires fit this way as well. Very tight! I did have to use an air compressor on the second Course to seat the tire, but I chalked this up to an older valve stem with average air flow. The Byway tires were set up with Clik Valves and their high-flow stems proved to work great with my Clik Valve converted Topeak Joe Blow floor pump. No need to remove cores or use a compressor there. 

The Course model here.

 I was a bit disappointed in the Course after initial mounting as it only measured out at barely under 50mm at 49.8mm. This was at 40psi. However, after only a few hours it was measuring a little over 51mm and by the next day it was close to 52mm, but not quite there. Okay....I chalk that up to the narrower rims then. But I would not be at all surprised to see the Course stretch that little bit more to reach 52mm after break-in. So far, after a couple of days and some riding, the Course sits a 51.2mm @ 35psi. 

The Byways were very close to 50mm right away and were there by the following day. I'll monitor the widths as things move along during this review. 

Both sets held air very well besides one of the Byway tires.  I am pretty sure I did not get the new Clik Valve tight enough, and since correcting that, the tire pressure retention hasn't been an issue. My past experiences with SG2 equipped WTB tires has shown me that I should expect these to hold air very well.  

As of this writing I have only done a quick, short test loop on each set of tires. I feel a free-rolling characteristic immediately. The Byway test was on a windy day, so I had to throw those results out. However, on my roll-down test with the Course, it was a windless day, and this tire was at the top tier of results, even before the tires have broken in. Impressive! 

The Byway tires side blocks are so far down the shoulders as to be ineffective here. 

I will say both models are very rounded tires. I suppose the Course would be a little more rounded due to the 23mm inner rim width, but even the Byway looks very rounded. Almost a tubular tire look to both of these models. In fact, the way the Byway looks on the rim it is readily apparent the side knobs, what there is of them, are going to be ineffective.  This could be said of the Course model, but again, a wider inner rim width might mitigate what I am seeing with my examples. 

The Course tires are on my Singular Peregrine Mk4, and they fit with room to spare there. The Byways were tried on my Noble GX5, and while they did clear the stays, it was only by a millimeter or maybe less. I did not feel comfortable with running these tires with that little clearance, so I swapped over to the pink Black Mountain Cycles MCD for those tires. I think the Macro, at 700 x 54, might have barely fit the Peregrine, but I won't worry about that now. All this to say that the very rounded profile of these tires on rims widths at the narrower end of the spectrum seem to allow for fit on bikes you might not think these tires would fit. With little tread blocks to worry about, as long as the casing will slide in your bike, these should work out, in dry conditions. I would not peg these tires as wet/mud tires anyway. 

After I get some "real riding" done on both sets I will return with an update.