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How much tire clearance do I need? Is 40mm 700c enough?

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How much tire clearance do I need? Is 40mm 700c enough?

Old 05-12-20, 07:35 AM
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TJtheWrecker
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How much tire clearance do I need? Is 40mm 700c enough?

I'm currently looking at 700x40c clearance on a bike I'm considering. The new specialized diverge has upto a whopping 47mm on 700c!

How much clearance do I actually need to ride gravel and light singletrack? Is 40mm enough?

Current Brand: Donnelly X Plor MSO, 700 x 40c
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Old 05-12-20, 08:19 AM
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plodderslusk
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I have both 700 and 650 wheels for my bike. I ride some pretty bumpy paths and 47 mm. slicks are barely enough for a good ride. On regular gravel roads 42 mm. is enough IMO.
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Old 05-12-20, 09:00 AM
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autonomy
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I ride 40mm MSOs and they're just fine for packed trails but as soon as I get into rooty/rocky trails that start to resemble singletrack I start wishing for a bit more volume/cushion. I'm going to try 2.1in 29r tires (if they ever get here).
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Old 05-12-20, 10:54 AM
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Elvo
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It depends on your skills and your comfort level. 33mm is enough for some while others require 2.2"+
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Old 05-12-20, 01:03 PM
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I have 42s and they are fine for packed dirt roads but marginal for rocky creek crossings and rutted descents. I have no mtb skills to speak of. If I had midwest type gravel like I see on the internet I would need a larger tire. If I were to get a different bike I would shop for something that would take a big 29er tire.
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Old 05-12-20, 03:04 PM
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40mm is fine for most roads you can drive a car on. Its fine for smooth single track. Obviously if it gets rocky or rooty, bigger is better. I'm fine blasting through single track on 40mm tires, but I have to pick my lines very carefully. If I put on 54mm tires, I can just blast straight through most stuff on just about any line I choose (within reason). 40mm on single track is going to take what to me is a ride that is too boring to do on a mountain bike and make it a lot of fun. But if you want to be fast or not worry about your line, ya want volume.
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Old 05-12-20, 03:33 PM
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Granted I come from a MTB background, but if you intend to ride singletrack I'd go for as wide a clearance as you can. I have a 700c 41mm bike and a 650B 47mm bike and the latter is unquestionably better in the dirt, yet still totally fine on pavement. And I think tubeless is key IMHO--I run really low pressure offroad - makes a huge difference.
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Old 05-12-20, 04:40 PM
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I like low pressures too. What I found was that the 38mm tires I have now are wide enough to go on just about anything without bottoming out. But the 2.35" tires on my mountain bike feel a lot better on rocky jeep trails or singletrack and definitely a lot better on long downhills. I recently did a ride on my gravel bike that featured a 7 mile descent on a closed road and I probably would have done it in half the time on my mountain bike. Just felt a little too squirrely on my gravel bike.
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Old 05-12-20, 05:53 PM
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40mm MSO's are fantastic for gravel! Tubeless you can take some roots on single tract.
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Old 05-12-20, 06:06 PM
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I clicked into here so ill repeat qhats been said.

I had those tires for a few years and would use the bike to ride the local river bottom singletrack thats pretty smooth and twisty. Its more fun that using my mountain bike since the width was plenty and the bike turned quicker.

I wouldn't want to use those tires for anything with roots, sand trail, climbing, mud sections, etc.
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Old 05-12-20, 09:05 PM
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I ended up buying a bike with 700c 47 mm clearance thanks to you guys!! Appreciate the advice and now relieved after making a decision.

Planning on owning multiple tire sets down the road as someone suggested, 1 for road/light gravel and 1 for heavier stuff
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Old 05-13-20, 08:38 AM
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I have clearance for 45mm, but haven't felt the need for anything bigger than 40mm (in fact, my new favorite tire only measures to 38mm and has been great!). As mentioned, really depends on your skills and the terrain. I'm around 215lbs system weight and have done some really chunky stuff and some mild singletrack with no issues, just taking a more careful line and slowing down a bit.

But with tubeless and appropriate pressures, you can do a lot with 40mm.
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Old 05-13-20, 10:57 AM
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I used to think 28 was plenty for almost anything, and it really was most of the time.

Then I moved to 40's and found them totally able to go anywhere a mountain bike could go except deep sand.

So following this progression, I suppose I'd like wider tires even more.

I think 40 is fine though.
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Old 05-14-20, 09:03 AM
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I used to think 28 was plenty for almost anything, and it really was most of the time.

Then I moved to 40's and found them totally able to go anywhere a mountain bike could go except deep sand.

So following this progression, I suppose I'd like wider tires even more.

I think 40 is fine though.
true. I find I ride 40-54mm in the winter (when I'm slow, out of shape and the roads are in rough shape), and 32mm in the summer - when I'm riding in groups where weight and aero make a noticeable difference (and when our dirt roads are smoother than our asphalt roads).
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Old 05-14-20, 01:11 PM
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Our gravel roads don't usually get smooth until hunting season. And then the forest service roughens them up again in the spring after the snow melts. But even when they are "smooth", they have big rocks embedded in them that will overwhelm anything less than about 35mm. Sometimes I wish they would spend their budget on something else, because I'm not sure it's absolutely necessary to do as much maintenance as they do.

When my brother lived in michigan, you had to drive on a gravel road to get to his house. It was amazing, reminded me of the strada biancha in Italy
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