Go Back  Bike Forums > Bike Forums > Cyclocross and Gravelbiking (Recreational)
Reload this Page >

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

Notices
Cyclocross and Gravelbiking (Recreational) This has to be the most physically intense sport ever invented. It's high speed bicycle racing on a short off road course or riding the off pavement rides on gravel like :The Dirty Kanza". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

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

Old 05-12-20, 07:35 AM
  #1  
TJtheWrecker
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked 26 Times in 11 Posts
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
TJtheWrecker is offline  
Old 05-12-20, 08:19 AM
  #2  
plodderslusk
Senior Member
 
Join Date: Nov 2004
Location: Norway
Posts: 1,399
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 8 Post(s)
Liked 4 Times in 2 Posts
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.
plodderslusk is offline  
Old 05-12-20, 09:00 AM
  #3  
autonomy
Senior Member
 
autonomy's Avatar
 
Join Date: Jun 2016
Location: Boston Roads
Posts: 813

Bikes: 2012 Canondale Synapse 105, 2017 REI Co-Op ADV 3.1

Mentioned: 13 Post(s)
Tagged: 0 Thread(s)
Quoted: 419 Post(s)
Liked 76 Times in 51 Posts
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).
autonomy is offline  
Old 05-12-20, 10:54 AM
  #4  
Elvo
Senior Member
 
Join Date: Oct 2006
Location: Orange County, CA
Posts: 4,335
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 438 Post(s)
Likes: 0
Liked 101 Times in 60 Posts
It depends on your skills and your comfort level. 33mm is enough for some while others require 2.2"+
Elvo is offline  
Likes For Elvo:
Old 05-12-20, 01:03 PM
  #5  
shelbyfv
Senior Member
 
shelbyfv's Avatar
 
Join Date: Jun 2007
Posts: 6,521
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 1552 Post(s)
Liked 745 Times in 455 Posts
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.
shelbyfv is offline  
Old 05-12-20, 03:04 PM
  #6  
chas58
Senior Member
 
chas58's Avatar
 
Join Date: Jul 2010
Location: Michigan
Posts: 4,166

Bikes: too many of all kinds

Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 918 Post(s)
Liked 162 Times in 130 Posts
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.
chas58 is offline  
Likes For chas58:
Old 05-12-20, 03:33 PM
  #7  
pbass
Senior Member
 
Join Date: Sep 2012
Location: Los Angeles
Posts: 669

Bikes: Surly Cross Check, Kona Rove ST

Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 112 Post(s)
Liked 56 Times in 44 Posts
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.
pbass is offline  
Old 05-12-20, 04:40 PM
  #8  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 19,709
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 358 Times in 273 Posts
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.
unterhausen is offline  
Old 05-12-20, 05:53 PM
  #9  
Gconan
Senior Member
 
Join Date: Apr 2018
Posts: 584

Bikes: Norco search xr

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 172 Post(s)
Liked 108 Times in 67 Posts
40mm MSO's are fantastic for gravel! Tubeless you can take some roots on single tract.
Gconan is offline  
Old 05-12-20, 06:06 PM
  #10  
mstateglfr 
Sunshine
 
mstateglfr's Avatar
 
Join Date: Aug 2014
Location: Des Moines, IA
Posts: 10,251

Bikes: '18 class built steel roadbike, '19 Fairlight Secan, '87 Schwinn Prelude, Black Mountain Cycles Monstercross V4, '89 Novara Trionfo, '18 Diamondback Syncr

Mentioned: 92 Post(s)
Tagged: 0 Thread(s)
Quoted: 3995 Post(s)
Liked 955 Times in 614 Posts
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.
mstateglfr is offline  
Old 05-12-20, 09:05 PM
  #11  
TJtheWrecker
Member
Thread Starter
 
Join Date: Apr 2020
Posts: 47
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 28 Post(s)
Liked 26 Times in 11 Posts
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
TJtheWrecker is offline  
Likes For TJtheWrecker:
Old 05-13-20, 08:38 AM
  #12  
Rides4Beer
Senior Member
 
Join Date: Oct 2018
Location: SC
Posts: 1,023

Bikes: Defy | Revolt

Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 531 Post(s)
Liked 424 Times in 237 Posts
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.
Rides4Beer is offline  
Old 05-13-20, 10:57 AM
  #13  
rosefarts
Senior Member
 
Join Date: May 2015
Posts: 1,156
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 437 Post(s)
Liked 193 Times in 105 Posts
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.
rosefarts is offline  
Old 05-14-20, 09:03 AM
  #14  
chas58
Senior Member
 
chas58's Avatar
 
Join Date: Jul 2010
Location: Michigan
Posts: 4,166

Bikes: too many of all kinds

Mentioned: 35 Post(s)
Tagged: 0 Thread(s)
Quoted: 918 Post(s)
Liked 162 Times in 130 Posts
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).
chas58 is offline  
Old 05-14-20, 01:11 PM
  #15  
unterhausen
Randomhead
 
Join Date: Aug 2008
Location: Happy Valley, Pennsylvania
Posts: 19,709
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Liked 358 Times in 273 Posts
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
unterhausen is offline  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.