700x38 - is it enough?
05-10-19, 03:15 PM
#1
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700x38 - is it enough?
I recently bought a 2016 Felt V55, which will take up to a 700x38 tire (actually, it will take a 40 in the front). It seems that current gravel bikes are running up to 45-50mm tires, making this Felt seemingly obsolete. My prior gravel experience was with a cyclocross bike and 33mm tires, so even a 38 seems wide. My question: Is it enough? I bought the bike as it was a good deal, it’s nicely spec’ed and it fit me well. I’ve been on a few gravel rides with it and found it incrementally more comfortable than a cross bike, but I have signed up for a 100km gravel race and wonder over the long haul is it will be enough.
05-10-19, 03:16 PM
#2
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Yes
05-10-19, 03:18 PM
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its fine, although in your boat I do put a 38mm in the rear and a 40mm (or larger) in the front.
For gravel, you should probably be in the 35-40psi range and tubless. No worries there. I find going much bigger just adds weight and makes my bike handle like my mountain bike. Nothing wrong with going bigger if you need the flotation or cush, I just personally find 38-40mm to be the sweet spot between acceleration, speed, and traction comfort. YMMV.
Enjoy the bike!
For gravel, you should probably be in the 35-40psi range and tubless. No worries there. I find going much bigger just adds weight and makes my bike handle like my mountain bike. Nothing wrong with going bigger if you need the flotation or cush, I just personally find 38-40mm to be the sweet spot between acceleration, speed, and traction comfort. YMMV.
Enjoy the bike!
05-10-19, 03:19 PM
#4
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"Enough" depends on what you're riding on. Both the surface itself and how dry or wet it is. Should do you, up until mudpits or pea gravel, fairly well.
05-10-19, 03:19 PM
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Yes.
Source - I have ridden many, many, many 100+ mile events and thousands more recreational gravel miles on 38s.
Are there situations in which it would be nice to have a wider tire? Yes. Does it mean I can't use the 38s? No.
Source - I have ridden many, many, many 100+ mile events and thousands more recreational gravel miles on 38s.
Are there situations in which it would be nice to have a wider tire? Yes. Does it mean I can't use the 38s? No.
05-10-19, 04:02 PM
#6
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Great replies. Thanks! As far as needing the “cush” part, I am a bigger guy (225lbs) but I find between the relaxed geometry, the carbon seatpost and a decent saddle, the bike is quite comfortable on the rides I’ve been on. I’ve done a few 50-60km rides and felt a fresh as a pavement ride. I did a 60km gravel race on my cross bike last year and felt like I’d been dragged behind a truck that distance.
The tires that are on it now aren’t really gravel tires (Bontrager LT2 Experts) so I will be investing in something more appropriate.
The tires that are on it now aren’t really gravel tires (Bontrager LT2 Experts) so I will be investing in something more appropriate.
05-10-19, 04:57 PM
#7
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05-10-19, 06:17 PM
#8
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its fine, although in your boat I do put a 38mm in the rear and a 40mm (or larger) in the front.
For gravel, you should probably be in the 35-40psi range and tubless. No worries there. I find going much bigger just adds weight and makes my bike handle like my mountain bike. Nothing wrong with going bigger if you need the flotation or cush, I just personally find 38-40mm to be the sweet spot between acceleration, speed, and traction comfort. YMMV.
Enjoy the bike!
For gravel, you should probably be in the 35-40psi range and tubless. No worries there. I find going much bigger just adds weight and makes my bike handle like my mountain bike. Nothing wrong with going bigger if you need the flotation or cush, I just personally find 38-40mm to be the sweet spot between acceleration, speed, and traction comfort. YMMV.
Enjoy the bike!
05-10-19, 06:33 PM
#9
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Tread isn't terribly important in gravel, there's no tread that's going to make you grip when the gravel is loose.
The smaller tire in back thing -- some people do that for mud clearance. I don't, because it usually doesn't rain that much where I live and I avoid riding in the mud if possible.
05-10-19, 06:41 PM
#10
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No, not important at all.
Tread isn't terribly important in gravel, there's no tread that's going to make you grip when the gravel is loose.
The smaller tire in back thing -- some people do that for mud clearance. I don't, because it usually doesn't rain that much where I live and I avoid riding in the mud if possible.
Tread isn't terribly important in gravel, there's no tread that's going to make you grip when the gravel is loose.
The smaller tire in back thing -- some people do that for mud clearance. I don't, because it usually doesn't rain that much where I live and I avoid riding in the mud if possible.
05-10-19, 06:41 PM
#11
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Nice bike! 38s no problem. I have run 35s and 40s. Any terrain that requires more I go to my 29er MTB with front suspension.
05-10-19, 07:13 PM
#12
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I have to admit the Felt was not on my radar when I was looking for a gravel bike. I had been going back and forth between a Specialized Sequoia Elite or a Kona Rove NRB DL but I am glad I ended up with this one.
05-11-19, 06:43 AM
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I see this repeated quite a bit and I don't think it's true and is more an individual issue than the bike news media likes to let on.
I can definitely feel a difference, based on tread, in grip on loose gravel over hardpack and even loose over loose packed dirt. Aggressive side knobs that are closer to triangular than rectangular seem to focus the pressure from the tire pushing into the gravel and get through to the surface where they can provide grip faster and better that other shapes. I found GravelKing SKs to be pretty abysmal on most of the dry gravel I've ridden - the just seemed to float on top and took forever to dig in. Something like the Kenda Happy Medium or Teravail Cannonball dug in fast and provided much better grip when the bike was sideways. Tread also makes a huge difference in braking, different surface treads affect the gravel different ways that aren't always easy to understand.
Always put the more aggressive tire in the front. You can run a slick in the rear with only some minor accommodation but slick in the front is not something I'd recommend - the traction just isn't there.
I can definitely feel a difference, based on tread, in grip on loose gravel over hardpack and even loose over loose packed dirt. Aggressive side knobs that are closer to triangular than rectangular seem to focus the pressure from the tire pushing into the gravel and get through to the surface where they can provide grip faster and better that other shapes. I found GravelKing SKs to be pretty abysmal on most of the dry gravel I've ridden - the just seemed to float on top and took forever to dig in. Something like the Kenda Happy Medium or Teravail Cannonball dug in fast and provided much better grip when the bike was sideways. Tread also makes a huge difference in braking, different surface treads affect the gravel different ways that aren't always easy to understand.
Always put the more aggressive tire in the front. You can run a slick in the rear with only some minor accommodation but slick in the front is not something I'd recommend - the traction just isn't there.
With that said, if I lived in the flatlands, I might be running a smoother tire.
05-11-19, 09:04 AM
#14
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I have found 38mm to be fine when I'm riding by myself. Sometimes I ride with some crazy descenders, and it is much nicer on bigger tires, like 2.25mtb tires.
05-11-19, 09:17 AM
#15
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A lot of the bikes that are taking the 45-50 mm wide tire are also running the 650b size. So theoretically, you could fit a 45-50mm tire on a 650b rim.
But there may be other clearance issues with that combo.
But there may be other clearance issues with that combo.
05-11-19, 12:42 PM
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seems to me that the big constraint for tire size on 650b is the chain stays. At least on all the bikes I have. Certainly there are narrow forks too
05-11-19, 04:45 PM
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You "recently" bought the bike, haven't yet done even a 100k gravel race (which is, at best, a middling distance), and you are already wondering if it's "obsolete"?
Worry less, ride your bike more. 38mm is a good tire size for much riding. And, as often as you may find it too skinny, you will find it too fat.
Worry less, ride your bike more. 38mm is a good tire size for much riding. And, as often as you may find it too skinny, you will find it too fat.
05-11-19, 05:18 PM
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You "recently" bought the bike, haven't yet done even a 100k gravel race (which is, at best, a middling distance), and you are already wondering if it's "obsolete"?
Worry less, ride your bike more. 38mm is a good tire size for much riding. And, as often as you may find it too skinny, you will find it too fat.
Worry less, ride your bike more. 38mm is a good tire size for much riding. And, as often as you may find it too skinny, you will find it too fat.
Two years ago I set my old Mooney up as a fix gear gravel grinder that would see a lot of pavement with 38 front and 35 rear Paselas. Rode the Trask River Trail to the Oregon coast. Tires were very good uphill and near perfect coming down. 18% in places both up and down. (35 is as big as I can go in back with any clearance and safety factor.)
Ben
05-11-19, 06:16 PM
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The fact that it only takes a 38 tire is probably why the OP got it for a good price. But I really like that size tire. Seems robust enough not to get pinch flats except under the most extreme conditions. At least it's not one of those bikes that would only take a 35mm tire, that's pushing it around here
05-11-19, 11:20 PM
#20
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Three of my riding buddies have bought new gravel bikes this spring, two of them came stock with 38s and they quickly changed them out for 42s and 45s. The third guy bought a bike with 650x47. Going into the bike shops here, you can find 33 & 35 tires for cross bikes and then 40-50 for gravel bikes. It seems 38 is a size they don’t care too much about. Hence my comment about if they were obsolete. I prefer to support my local shop but I might have to order something online.
05-11-19, 11:24 PM
#21
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It depends on what you are happy with. There are conforming 38 tires and there are frozen garden hose feeling 38 tires.. I personally use wider for gravel but that is me.
05-12-19, 02:18 AM
#22
Gravel Rocks
Depends on what kind of gravel you are riding, how much you weigh and how fast you want to go plus other factors. Michigan fire trails as an example have quite a bit of sand and bigger tires are great in that environment, 45mm would a good choice if you don't want to get off and walk as much. B-roads with ruts and big gravel I want 40mm or larger. Regular dual lane A gravel roads that have fine gravel sub 40mm works well.
05-12-19, 04:25 PM
#23
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I just finished a 70km ride with a friend who is riding with 42mm Sawtooths. For most of the ride there was very little difference between us until we got a stretch with thick pea gravel about 3-4 inches deep. He was able to handle quite a bit easier than me. I felt like I was pedalling and not getting anywhere. Overall I was pretty pleased with how the bike felt and performed though.
05-12-19, 05:47 PM
#24
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I did two of the same centuries with two different tires a week apart. A route of about 50% gravel/trail and 50% paved. Hutchinson Overide 38 and new too me WTB Riddler 45. Both have pros and cons and the times/effort between them was dictated by the wind direction, not the difference in tires. I did the C&O/GAP last year with the Override. This year will be with the Riddler. I have multiple wheels sets and swap around because it is easy to do so I don't have to pick just one tire. My "gravel" bike is also a fire road bike, road bike, and a touring bike. More often than not in the same ride. There are people that do the same with a 28 or 32 and are perfectly happy. I have no idea how but.... 
Last edited by u235; 05-12-19 at 05:51 PM.
05-12-19, 06:44 PM
#25
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I did a 65 mile gravel race earlier this year on a single speed with slick 32s. A 40 up front and a 38 out back is actually a great setup.
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