Should you run 650b or 700c on your Gravel bike?

With the multitude of wheel and tyres choices on the market today across 700c and 650b variants, and a number of bikes including the VeloVelo Hiraeth Adventure bike that are designed to run on both - what are the best options for you?

First of all lets look at the options…

700c with a wider gravel orientated tyre is a development of what we’ve seen on cyclocross bikes for years and years, they were quite often limited to 35mm but with the advent of Adventure and Gravel bikes some of which are now designed to take up for 50mm wide tyres there are plenty more options. 700C provides a somewhat familiar feel if you come from road bike world, and if you run a wheel set like the Hunt 4Season you can easily switch between a road orientated 28mm tyre to a more gravel happy 35-40mm tyre on the same bike.

650b opens up a whole new world of bigger tyre combinations and adds a big leap in capability for your bike. We quite often switch up our 28mm road wheel set for 650b running 47mm WTB tyres and it gives the bike a much more MTB hard tail feeling but retaining the drop bar and faster road capability. We also see a trend of touring customer utilising 650b in ‘RoadPlus’ format - essentially big comfortable road going slicks that are fast paced but also incredibly forgiving on long multiway rides, maybe not one for weekend club rides on the road - but perfect for longer solo mile munching.

So what are some of the use cases? 

Well, its very dependant on the terrain that you’re taking on, here in the UK in the summer we do not have that many aggressive gravel tracks, most of our terrain is dusty hard packed dry mud and chalk which is very well suited to a 700c and a all-road tyre like a Panaracer GravelKing. We run the 37mm or 43mm GravelKing for the majority of this type of ride with huge success, grip and comfort.

For those that head into the forrest tracks, bouncing over rutted paths and tree roots or more rocky mountain territories we’re probably moving into the realms of 650b where you can run bigger capacity tyres and a tad less pressure. 27.5” MTB Cross Country tyres are quite often a choice for those hitting the rougher stuff but we tend to stick to 650b WTB Byways in the UK especially when we’re heading somewhere new where the smaller capacity GravelKings might get a shock.

650b for the road? As mentioned, we see some tourers and world travellers doing this but honestly as bike manufacturers are building 700c focussed ‘Adventure or Endurance’ frames with 35mm clearances now I do not see a need for more on a road bike.

In conclusion if we could sum it up in a sentence, most UK Gravel rides that we’ve done are perfectly suited to 700c 37-43mm tyre combos and only if you’re hitting up paths and tracks that are probably better suited on MTB do we think that 650b is really needed. That said… I personally still enjoy the feel of taking off 700c road wheel set and chucking on 650b just because it feel like it feels like a totally different bike - when you have one bike taking you everywhere that difference keeps it feeling fresh.

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