Noonievut

I only have one set of wheels for my gravel bike and I'm not looking to add another. I have 700x40 Touareg set up tubeless and so far I've really liked how they perform on the gravel trails and roads that I ride, and on pavement. After 1,500+ KM on mixed surface I'm starting to notice the rear tire wearing very slightly (the centre tread pattern), when compared to the front. The tire still does great on gravel so no complaints there...so far! However, I have this nagging thing where every time I ride this bike on pavement, and in particular a ride where it's mainly pavement and there is some reason I'm not opting for the road bike, that I'm just wearing the tread away and thus ending its effective life on gravel sooner...and its overall life.

One option is I just keep riding them and when they're no longer performing well on gravel, I replace them. They're not expensive and I already have a second set. Maybe I get a full season out of one set? I do ride this bike in winter (paved roads) and if they go a full 12 months that's only like $120 Canadian.

I'm also curious how a slick would perform on the gravel I ride. Assuming it would be far better / longer lasting on pavement, the only deal-breaker is how it performs on some very specific gravel I ride frequently...where I have steep climbs/descents (some of them twisty) on loose gravel. The Touareg have performed fine but even on some climbs I have to stay seated otherwise back tire wants to lose traction (I would assume a slick would be even worse?).

I see/hear experiences where people get 10,000km out of a gravel tire, though I'm not sure where they ride/conditions, etc. I love the idea of set it and forget it!

What have been your experiences in relation to above?

tdilf

I would rotate the tires and use them until they totally wear out. Slicks on loose gravel works until you get into having to turn a lot - the wider and softer the slick the better in this case. I don't have any gravel that is so steep that a slick would not work.

mstateglfr 

If your tire is only very slightly worn after 1500km, then maybe you will get that magical 10000km out of the tires.
Like you said though, they arent expensive and you have an extra set already- there is no downside to using them how you are. Even if you want to switch to slicks, you still have tires with very slightly worn tread and another new set hanging in wait. Thats a lot of KM to ride before you need to actually buy new tires.

As for slicks on gravel- I think it totally depends on what you call gravel and how you ride it.
If gravel means a bunch of loosepack singletrack, then maybe a slick isnt great since tread helps grab firm ground. Or if your gravel is really loose, especially on climbs, then tread may be best.
I ride gravel roads- the gravel varies from mile to mile depending on how recently it was laid and how frequently its been driven, but its predominantly hardpack with scattered rock on top. A slick works perfectly fine for me as I am using some right now(technically semi-slick, but its really no different from a slick).
I do notice that on steep climbs I now hold my weight differently when standing to climb to help ensure the rear wheel doesnt spin out. It isnt tough or some extreme change at all.

dwmckee

Slicks on gravel is my most common choice as long as I do not have too much pressure. If I expect sand, mud or much wet grass then I look for some tread.

Badger6

How loose, OP? Also, not all slicks re the same. The key is a bit wider than road slicks (minimum 32, 35 is better, measured when installed and inflated to the proper pressure) and a supple casing will generally be okay...but as dw said above, as soon as you are dealing with mud (not wet gravel, actual mud), grass, or sand, the slicks won't work so good.

Noonievut

Not too loose I guess...think of a rail trail with crushed gravel but that gravel is loose when climbing 20% grade in that the rear tire doesn't want to stick. I have 40's right now with the Tourareg, and they feel like the minimum for getting up this hill without having to dismount due to losing traction.

Badger6

20% isn't a rail trail, but I get your point, I've been on surfaces like that and they are bound to feel loose even if they aren't. You can ride a 32 or 35 on that, I have. You just have to apply the power carefully and evenly, and make sure you aren't running at the high end of the pressure range for your chosen tire width. For instance, on looser gravel, I will run my 32s (measuring 35) between 40-42 psi (which is probably too high).

mstateglfr 

Rail trails typically dont exceed 3% or so, since trains used the routes. Ive been on 20% or greater hills not even a handful of times...I really think I could count the number of times on one hand. Once a gravel road hits 16 or 17%, thats just nuts and exhausting for me.

scubaman

+1 for this approach. I’ve found slicks to be fine on all types of gravel; but less good on dirt/mud and on wet leaves etc. Pretty much everything is bad on sand; and I use studded tires on ice and snow.

I’d be cautious about the advice to rotate your worn rear tire and your less worn front tire! On a bike, failure of a front tire can be much more dangerous, because you lose steering control, plus normally more of the braking is done with the front wheel. Seems like a safer bet to replace the rear tire more often.

Boatdriver

Based on other suggestions, I toss the worn out rear tire, rotate my not bad front tire to the back and put a new tire in the front. That style of rotation keeps your front in good shape for turning and braking, but allows you to minimize your expenses on tires.

Noonievut

I'm going to try this next time, assuming front is in good shape to become a back tire.

dvdslw

There is a valid argument that slicks are better for gravel because a loose surface like gravel is constantly moving blow your tread so having knobs actually gives you less traction than a slick. A slicks smooth surface will make more contact with a loose surface and give you better grip plus roll faster in the process. But, if you add mud, wet grass, or sand you're better off with some knobs.

dwmckee

All tires stick to gravel pretty well, the problem with gravel is that the gravel itself rolls under the tire, slick or not. Slicks DO NOT slide across the gravel, gravel rolls under it, just like it does with treaded tires.

Noonievut

The last two posts have me thinking!

I’m guessing that small/fine gravel vs. the dirt you may find on a mountain bike single track require a different tire if you want traction. I just always figured that more tread = more traction on gravel, and for gravel we were always compromising traction for speed on smoother surfaces. Where I ride my gravel bike, it’s only small/fine gravel or pavement. No mud.

Badger6

A very good gravel compromise is a tire with very low profile (slick, or file tread) in the center, with a narrow strip of tread on the shoulders. The Challenge Chicane or Challenge Gravel Grinder come to mind, in 32 or 36 respectively. Or in 38, the Specialized Pathfinder Pro is also very fast rolling, slick on the center with a nice grippy tread on the shoulders, and a cinch to set up tubeless.

Chilepines

I agree with all the above and would emphasize the importance of tire pressure. Lower pressure smooth tires will almost certainly beat higher pressure tires with knobs. I'd get file tread tires if I didn't also ride my gravel bike on single track trails and unmaintained New England back roads.

dwmckee

Yep!

You do need tread in mud, sand, grass, but on good gravel slicks with the right tire pressure and then you can really kill it on the paved portions. The Vittoria Terreno Zero or Dry has a smooth center section and tread on the sides as mentioned above and is a great all purpose tire as well. I ride Rene Herse and Challenge Strada Bianca mainly because where I ride has little sand, mud or grass.

Noonievut

I went for a ride on my usual gravel trail (plus mixed surface) route yesterday with a mountain biking friend. He was following me as it was his first time on some of these trails. Through sections of loose gravel he later commented that his 2.6" knobby tires were offering poor traction, and he noticed my back tire sticking much better. Now I'm convinced that knobs and the gravel I frequently encounter, do not mix.

zandoval 

I wear my tires down but I don't wear them out. I think its cause I weigh about 250# and not so much the terrain I ride. I rotate my tires back to front when the rear wheel gets worn. I also go for a mid priced touring tire and just try not to cry when I have to replace...