Gravel Tire Clearance - How Big is Big Enough

Continuing with my gravel questions, how much clearance is big enough? More specifically, is clearance for 700x45 enough?

I have almost no gravel riding experience so I have no real concept of what a 45 mm tire lets you ride on versus something larger like 50 mm or even 57 mm. For context I’m considering a Lauf Seigla (max 700x57) and a Ribble Gravel SL (max 700x45 or 650x47 but I’m unlikely to get 650b wheels just for 2 mm more tire).

I know the answer will invariably be “it depends on what you plan to ride on” but I guess I’m looking for context / perspectives / experience on what I could ride on with 50 mm or 57 mm tires on a gravel bike that I couldn’t ride with 45 mm.

Thanks!

Most of my experiences comes from riding in the USA’s Southeast. Roads varried from smooth hardpack gravel to very chunky, river rock-esque gravel. Sometimes with singletrack. For true gravel riding and light singletrack, 700x45mm should be plenty. My current bike is only 700x42mm. Rarely, and only for very short sections, have I ever thought “Man, I really wish I had bigger tires” in a gravel event.

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For most true gravel roads, I’d say yes.

For Jeep roads (ie exposed rocks, bumpy surface), maybe for short stretches, depending on the road. But if you’re going to be riding roads like that, a gravel bike is the wrong bike, and a MTB or similar is better.

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Seigla is a super comfortable bike. Highly recommend it! They have (or will have soon) us distribution from Va.

I’d argue anything bigger than 45, a XC bike is what you really need. My boone starts getting tight at 38, and I really can’t imagine going much larger on that bike

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This.

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Here’s my story. I have an S-Works Crux set up for gravel. It’s super light. It was a former $8000 build when I got it (used, cheap, 3 years old). My max tire is 45mm front, 40mm rear.

I rode around southern NM with various friends. Two friends had Salsa Cutthroats (55-60mm tires) and they were faster or just as fast in almost every condition. On flat ground with smoother roads, they kept up with me just fine. When it turned sandy, I’d bog down and they would just ride away from me. When it turned rocky and chunky, I’d be struggling and they would ride away from me.

My conclusion is that more tire will be faster just about in every condition for gravel. My light bike with “skinny” tires would theoretically be faster on smooth packed gravel roads and/or long climbs where light weight would help. Personally, I hardly ever encountered those conditions.

Now a race like BWR, you have a tough choice. Be fast through the off road sections or be fast on the 80 miles of paved roads.

My advice is to buy more tire than you think you need if you ride in any kind of harsh conditions. If you ride trails and smooth roads, then it doesn’t mater that much.

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I LOVE my Cutthroat running 29x2.2 Rene Herse knobby tires. It’s super stable on rougher terrain which I often encounter in the Northeast US, and it’s fast enough on the smoother stuff.

So much depends on how gnarly your gravel is and how confident you are as a bike handler.

The Seglia looks like a great bike and gives you the option to run big tires if needed! That’d be my pick if I didn’t get a deal on my Cutthroat.

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I think that’s the part where as a rider you have to pick what’s best for your situation. What kind of terrain are you riding? Is it just for fun or is it for competition? Or maybe it’s a bikepacking setup that they’re going for?

For me, anything over 45mm would be overkill. All of my tires were 38-42mm. The Specialized Pathfinder 38 or 42mm or Maxxis Rambler 40mm were my jam. I raced BWR and many regional events. At the front of the race you didn’t really see tires outside of the 38-45mm widths.

It’s a hard question to answer without knowing more about the rider and their goals. But ultimately I’d still say that 45mm of tire is “enough” for almost everyone.

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That is probably the max for almost all gravel bikes, except those that are designed around 29" mountain bike tires specifically. However, those do not ride as well on regular tires with smaller widths.

Most 700c gravel tires typically max out at 42 mm. Once you go wider, they typically come in 650b. A lot of bikes like e. g. the Open UP can take 27.5" mountain bike tires.

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Midwest has-been/never-was-fast cx/graveler here:

45mm is a gravel tire. 52mm is an old school MTB tire. Tread patterns fudge each in either direction.

I rode lots of gravel miles on a 40mm front and a 35mm rear because my cx bike couldn’t handle more between the chain stays. And yea, it does depend on the surface and your abilities, but I’m a ham-fisted Clyde on an XL bike and I rode plenty of B-road/two-track in Iowa…

I never really wanted more volume upfront, but that might just be because the rear was so limited at 35… Also, those were tubed tires for the most part, and I’m now on 36mm tubeless on absolute crap pavement…

I think you’re No VA? and I haven’t ridden those roads or your available single track, so I can’t really say if a gravel bike vs monster cross vs drop bar mtb would work best, but riding a CX bike on midwestern single-track really made me concentrate on even the easy trails with a 35mm rear…

TL;DR - you’re smaller than I am, I have no special skills, I managed with a 35 tubed rear… You get a 45mm tubeless, you’ll figure out how comfortable you are on your local routes. I wouldn’t hold out for a 700x50mm fit for “gravel” or “multipurpose/multisurface” unless theres is a specific spot I wanted to hit that called for more.

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I’m a good bike handler and have never wished for more tire riding 38mm specialized Trigger tubeless. Getting your tire pressure right for the terrain is more important that a wider and wider tire IMO. I can only contrast this to riding my mtb with 2.2 tires, but I wouldn’t think that would be faster on any terrain deemed ‘gravel’ (obv they’re better on single track)

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KW, you’ve obviously never ridden though a deep sandy section or a rocky section on your 38mm tires while trying to keep up with other riders on wider rubber that just sail on through and leave you in the dust.

I don’t mind being slow by myself but it was getting frustrating being dropped by friends every time the terrain became challenging.

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To each their own, but I’m pretty sure Unbound is/was won on 38-42mm at 30-40psi and that’s considered ‘the’ gravel race. I would ride a fat bike on a beach, but I wouldn’t opt for huge tires just to get through a few sections that constitute a small percentage of a ride.

To answer OP, IMO 42 is def big enough, you’d be fine as low as 35.

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Love my Seigla but the Maxxis Rambler 40s have been plenty of tire so far. Can’t imagine needing 57s but nice to know it’s an option.

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Perfect bike for tour divide type trails. I’ve ridden some sections of the tour divide route on my Diverge with 38mm tires and I was completely under biked. A cutthroat with a suspension fork and 2.4s would have been much better.

Also a great bike-packing bike when you don’t know what kinds of trails your route will serve up.

But for most “maintained” gravel roads I have ridden on (which is probably 95%+ of my gravel riding), a bike like the cutthroat would be overkill. Not necessarily bad, just not necessary.

When I rode the White Rim a couple of years ago, I thought for about 5 mins about putting 50s on my Diverge and riding it on that. Glad I didn’t. I put 2.2 Conti Race Kings on my full sus MTB and that was the perfect combo. But I have heard of people riding that route on a gravel bike.

So depends on what you want to optimize for. If optimizing for the 95%+ of the time you’ll be riding true gravel, 45s will be more that fine. But if you want to optimize for the maybe 5% of the time you might ride some rough stuff, a Cutthroat better. I went through this decisioning when I bought my Diverge. So it resonates.

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To me the question is how fast you want to be. At some point, we are talking about a mountain bike with drop bars, and one might debate that a fast XC hardtail might do the trick, perhaps even better.

However, in my mind gravel riding should be faster and you simply need to accept that you will be underbiked in certain circumstances. Faster means narrower tires (compared to a mountain bike). I test rode a 3T Exploro with mountain bike tires, and this is definitely not a combo you want to ride on the road for extended periods — it just wasn’t fun.

In the end, tire choice is mostly a function of route choice in my opinion. 35–40 mm should suffice for all intents and purposes.

Sand is tricky and requires skill and practice. Sometimes being on narrower tires works better on sand, because large, voluminous tires tend to “float” on the surface rather than “cut into” the sand.

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I was tempted to post this earlier, but didn’t. I know, not super relevant to the gravel tire question at hand (sorry). But considering what CX riders do on 32-33mm tires…

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Just remember that CX riders use those size tires because they have to, not necessarily because they want to or it is optimal.

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From my experience, it’s really just a function of what you ride and when. I’ve got two sets of wheels for the Giant Revolt Advanced Pro I just built up, one with 700x45c Pirelli Cinturato Hs and the other with 700x50c Maxxis Ramblers. I’m a Clydesdale (6’1" and 210 lbs currently, although working on significant weight loss) for reference.

Riding in Northern New England (mostly VT) I used just the 700x45c tires last year and really liked them for the vast majority of terrain. That said, there were some areas I wanted a bit more meat on the tire (i.e. 700x50c) for mud season, some long dirt road sections with intense washboards, and riding Class IV roads for longer stretches. I also live on a dirt road and can ride all day with maybe a few miles of pavement at the most.

If I didn’t have mud season or Class IV roads, I’d be perfectly happy with 700x45c tires. That said, bigger tires gave me more confidence (and comfort!) on some very chunky gravel rides where I live, and also at events like VT Overland. At this point, there are quite a few mainstream gravel bikes that can handle 700x50c or more, too. Off the top of my head: Lauf Seigla (700x57c), Giant Revolt (700x53c), Niner RLT 9, Fezzari Shafer, Canyon Grizl, plus more niche bikes like the Otso Waheela C and Warakin, Bear Claw Thunderhawk, etc.

In terms of a bike, I’d go for lots of clearance so you at least have the option of going fatter if you want to. Depending on where you live, the amount of time you have available for exploring, and what you actually enjoy riding, your demands can change quite a lot. Start with a 40-45c tire and see how it goes. If you end up enjoying riding on the chunkier side and want a bigger tire, you can always swap them out.

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Have ridden some daft stuff on smooth 35c tyres but also have some 650b x 47c knobbled tyres on a second wheelset for rougher stuff where I know there will be hardly any road but plenty of gravel, sand, mud or single track. If buying a frameset again, would consider clearance for 2.1" but this all depends what, where and how you plan to ride.

Instead of another frameset, am taking the luxury option of getting a CX bike but in a ‘one adventure bike’ situation, more clearance for me.