Spoonrobot 

Thinking about tires I want to ride for the upcoming fall gravel season. All the things to think about, are wider slicks better than narrower knobbies? How much does the terrain and road surface dictate the level of tire aggressiveness? If you lose x time on the flat or paved sections with knobbies do you make up x+5 time on the descents due to increased traction/cornering confidence? Is tire weight more important than rolling resistance to a point? Does wheelsize make that much of a difference when choosing tires? 650bx47 is better or worse than 700cx47?

Right now I'm running Kenda Happy Medium 700x40 with tubes and have been very happy with how they perform. But now I can't help but wonder if something less aggressive would be better for the relatively flat and compact courses that are ridden in the fall. The tires also have aggressive side knobs which I'm fairly certain helped keep me upright during a two-wheel slide last year. I'm pretty sure slicks would have slid out and ended my ride within a couple miles of the finish.

For anyone riding for speed or competition what kind of tires have you used and/or what kind of changes have you made? Negatives/Positives?

Personally, in 2015 I started racing on the most aggressive tires I could fit in my frame. 700x40 WTB Nanos - they're like mini-mountain bike tires. They worked great in the wet, soft and muddy season we had but when I happened to try some less aggressive tires on a lark I was shocked at how poorly the Nanos rolled. So I decided to change to a tire with micro knobs on the tread. Surprisingly in the mud and muck it feels about the same, slow and loads up with mud fast just like the Nanos. But on the road it rolls great. So a positive change.

For this year I'm thinking of going with a slightly wider tire that is also a little more aggressive but running it tubeless - WTB Resolute 700x42 - it weighs the same but should roll a little better without the tube and give me about the same speed on pavement, I'm hoping, while being faster on the really rough stuff. I do have half a mind to try something really different and go 650bx47 WTB Horizon or Byway to get a tire that would be much faster on pavement but the slicker tread would be a real liability on mud or challenging rough sections.

Opinions, conjecture, rants and ramblings welcome. What's everyone thoughts on riding fast and how it relates to tire choice?

ETA: Added links to tire pics so everyone can see the tread differences.

Rollfast

Slicks?

Metieval

When I think Average speed.......... a couple of really fast descents isn't really going to boost my average much.

what will increase my average speed is the faster speed on the flats, and the faster speed on climbs. which is the bulk of the whole time. thus Lighter/Less RR is better?

at what point do we see a difference in Diameter? Asking with the 700 vs 650 in mind, Because is there really that big of a difference between a 650x47 and a 700x38 ?

If you have a dry course I'd think the Byway would be fast, while still giving you cornering, albeit a weight penalty. how much of a penalty over a tubed 700x40? probably not that much at all.

I have never ran the Nano 40, but In my opinion based on 29er time and a nano 2.1 they are slow as heck! and on Dry packed offer absolutely nothing! even soft packed they seemed slower. I am assuming the only time the Nano might have an advantage is deep loose?

Lettting your course/conditions dictate your tire, might be the faster choice. what tire that is... ( I am clueless )

Metieval

@Spoonrobot... can you fit a 700x43 GK SK? might try them

wheelsmcgee

Spoonrobot 

@Metieval I looked at the GK SK but thought the knob profile was a little weird and was worried it would clog and stay clogged with the silty mud that sometimes makes an appearance for a few dozen yard in almost every event. I did really like the GK slicks so maybe I'll take a closer look at the SKs. There's a couple guys I see using them and they seem happy.

That's a really good point about the average speed. I tend to over focus on descents as it's a weak point for me but in the overall scheme of things I've rarely been dropped on a descent. In 2015 I did have issues descending due to an incorrectly applied centering mark on a pair of handlebars - but I've since recovered and now my descending issues are due to good ol' fashioned cowardice. So thinking maybe lowest rolling resistance and lightest weight maybe be a better focus area.

The difference between 650bx47 and 700cx38 would be right around 20mm per this handy tableau tool. Now I think this can be significant depending on the course (rough, descents) but for most I'm not sure how much of a factor it will be. I seem to prefer, physiologically, larger wheels but if a smaller wheel can save weight without giving up much rollover...might be worth changing.
@wheelsmcgee we're thinking along the same lines. Being able to corner with more confidence on the flats or on paved turns where there's gravel washout can definitely be an advantage. It makes the riders who have to brake, either due to technique or equipment limitations, sprint to get back into the pack. Over 50-100 miles this easily weans out the less technical and fit riders.

I think the Byways may be the way to go. It's too bad they don't come in 700c wheelsize. I don't think there's a comparable tire that is 100% slick in the center but also with size knobs in that wheelsize?

Although talking to a guy earlier this week on a group ride he was saying the 2.35 Schwalbe G-Ones are so wide they offer similar grip to a good 2.0 knobbie tire. I'm not entirely convinced that's true but my frame can fit up to 50mm so I'm wondering if 50mm slicks (if any exist) would be worth looking into?

Facanh

In muddy and wet situations you will die with a slick, doesn't matter how big it is.

If you can stretch that 50mm I would go with an XC MTB tyre. There is the Continental Speed King II but it's a "bit" fragile, super fast tho.

https://www.bicyclerollingresistance...racesport-2015

Or the Thunder Burt which also comes in 2.1.

https://www.bicyclerollingresistance...snakeskin-2015

In my experience (so according to my butt) small knobs don't necessarily slow you down compared to a slick.

HTupolev

Did he say this in general or with respect to the particular ride you were on? Knobs and width aren't functional substitutes for each other. Slicks can be viable on gravel, but making them wide doesn't magically help them bite through mud.

TimothyH

@Spoonrobot

I have a pair of Gravelking SK 35's. Low miles. Just sitting in my garage. You can have them if you want.

Just reach out.


-Tim

Metieval

I have a different take on slicks on gravel that sets me apart from a large majority. Partially because I ride 25c slicks on snow on pavement all winter every winter.

The ONLY times that slicks kill me is 1/4 mud over packed, and then on grass.

and the last time I had the 29er in mud the knobbies were slicks after 5-6ft anyways. Mud packed slicks. Really heavy slicks at that!

I wonder now If I shouldn't try 32-35 size slicks. However, for me, It really isn't about width, but tire Pressure. I don't think I could get away with 35-40 psi in a 32c tire. but I can get away with lower psi with tire volume. lower psi means less deflection = a much more enjoyable ride

TBeghtol

Subscribed

Spoonrobot 

@Facanh I've actually almost bought the Speed King a couple times but deferred for more aggressive tires. Might be time to revist - based on the Bicycle Rolling Resistance tests I picked up a Rocket Ron/Racing Ralph comob for my MTB and the speed on pavement compared to my previous tires is eye opening. The trails have been too wet to ride but I'm curious to see how it transfers over to dirt.

@TimothyH thanks for the offer but I've pretty much settled on 40+ as being the width I ride. I, uh, not light enough to really benefit from 35s on gravel.

@HTupolev we were riding pavement but discussing singletrack and gravel, mud is not something I'm too concerned about. The sections where there's sticky silty mud are usually short enough that it's not a major issue just something I was over-thinking about the GK SK. His point was similar to Jan Heine where gravel is often loose over hard so knobs don't make that much difference, for dry singletrack he was saying the same thing. Watching his line on another ride he seems to be a more "steering" than "leaning" rider so his experience may back his opinion. I had a phenomenally fast ride at a muddy event earlier in the year where I was running slick WTB horizon tires. They're terrible tires in the mud but since the course was flat and the bike I was riding was low trail I was able to just pedal as hard as possible and steer my way all over the place. With a higher trail bike I would have washed out several times at the speed I was going due to having to lean much more - or just ridden much slower. I've also not been able to get the same performance out of slicks on gravel as I do with tires that have side knobs, despite putting in a lot of practice. I think it's much more technique based than first appearances let on.

@Metieval The snow we get down here is often over glare ice so it's hard to ride at all if there's snow on the ground. When I lived in Chicago it was so cold riding around on 23s was much less a problem. Here near Atlanta I had trouble on 2.25s! During the warmer months when it gets really wet down here the tire tread doesn't make as much a difference as the width. It's not unusual to have a <40mm tire sink 1/4-1/2" into the "road" whereas a wider 50mm+ tire will be about half as much if not less. I remember hitting a soft section next to a guy on those 2.35 G-Ones, neither one of us braked but my 40mm tires sunk into the road and he just floated by. Less traction sitting on top of the mud but a lot faster if one can handle it.

Metieval

Our Limestone driveways are soft all winter.... My 29er just leaves ruts. And it is very draggy. If that was what I rode all winter, I'd probably buy a fat bike. Our Paved Roads are salty... which is why I just ride the Single speed on 25's not icy just wet and grimy.

Doesn't Jan ride Low trail... which is why he steers more than leans?

Koyote