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Do gravel tires feel a lot slower to you than road tires?

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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 : "Unbound Gravel". We also have a dedicated Racing forum for the Cyclocross Hard Core Racers.

Do gravel tires feel a lot slower to you than road tires?

Old 08-28-18, 12:03 PM
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Originally Posted by redlude97
Interesting. I'm kinda surprised since the 38c GK weighs 320g which is lighter(and thus more supple?)
GK is lighter than the Compass tires because the tread rubber is thinner at the centerline, but it's got a bead-to-bead protection layer which stiffens the tire significantly.

I haven't actually ridden on GKs, but I wouldn't be surprised if the Compass tires roll better.

than the compass bon jon which has been tested as one of the fastest https://www.bicyclerollingresistance...-jon-pass-2018
The Bon Jon actually did fairly poorly in that test IMO. It tested faster than most other tires in the website's touring category. It is not a touring tire.
And the Bon Jon did extremely poorly in Tom Anhalt's testing on rollers.

I'm interested in whether these small-drum tests accurately capture the relative impact of sidewall flex versus tread flex. Tom Anhalt thinks they do, but his confidence seems to be based on a fairly shallow study, and I'm not convinced it's been well-characterized for the general case.

Last edited by HTupolev; 08-28-18 at 12:07 PM.
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Old 08-28-18, 12:20 PM
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Originally Posted by HTupolev
GK is lighter than the Compass tires because the tread rubber is thinner at the centerline, but it's got a bead-to-bead protection layer which stiffens the tire significantly.

I haven't actually ridden on GKs, but I wouldn't be surprised if the Compass tires roll better.


The Bon Jon actually did fairly poorly in that test IMO. It tested faster than most other tires in the website's touring category. It is not a touring tire.
And the Bon Jon did extremely poorly in Tom Anhalt's testing on rollers.

I'm interested in whether these small-drum tests accurately capture the relative impact of sidewall flex versus tread flex. Tom Anhalt thinks they do, but his confidence seems to be based on a fairly shallow study, and I'm not convinced it's been well-characterized for the general case.
My understanding is that overall casing stiffness doesn't really affect the RR, and only at the contact patch affects RR so a thinner tread should perform better. 18.6W at 60 psi is pretty respectable for a 35c, certainly not expecting it to be in the gp4000s range but better than say the gp4 season and about the same is a michelin pro4 SC and that was with it tubed, set up tubeless I expect the number are even lower. I do agree that roller tests may not be completely representative of real world RR. I haven't ridden the bonjons but I know plenty of people that do since I'm based in the PNW and they seem to think they roll fast on pavement, plenty of the randonneurs run em and occasionally show up to the fast group rides.
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Old 08-28-18, 01:46 PM
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Originally Posted by Spoonrobot
Casing stiffness has a huge effect on drum roller resistance because the tire deforms so much around the roller both on a lateral axis and a horizontal axis. I suspect it would have less effect on the road but would be very difficult to measure.
If it's significant, it could possibly be tested by comparing differently-designed tires on a tiny drum and a huge drum, and seeing if their relative performance changes.

Intuitively, it seems to me that the drums would underemphasize radial suppleness relative to tread/axial suppleness. The sidewalls smush down and outward whether a tire is on the road or on a drum, but tread rubber sits a lot flatter fore-aft on a road than it does on a small drum.

I'm also unconvinced of the efficacy of testing tires with any tread that protrudes more than mere file tread on rollers.
I can see several potential issues once you throw knobs and off-pavement riding into the mix.

First, the firmness of the riding surface will affect how much knobs actually flex/deflect/whatever off of it. A knob that bends against pavement may just sink into a soft or loose surface, which probably has implications for the amount of energy wasted.

Second, large knobs at the centerline can probably have "suspension"-like issues on firm surfaces. I mean, if you ride really aggressive MTB tires on pavement, you can feel the bicycle rumbling from the tires. This effect, if significant, is probably one of those things that demands field testing to characterize.

Third, on loose surfaces, the power required to plow through the surface might matter.
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Old 08-28-18, 01:55 PM
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interesting discussion on ST and here now, did one of you ask about the unicorn treadless wide tire? I want to hear Tom's opinion on that. He seems to be stuck on the challenges, which my only experience is with challenge cross tubulars but they have the most supple casing of them all even though they use polyester thread compared to some of the cottons
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Old 08-28-18, 02:15 PM
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Originally Posted by twodownzero
The reason they feel slower is that the higher volume tires transmit vibration to your body at a different frequency. You might be surprised that they may not be slower at all.

I've been riding my touring bike lately (something like 1000 miles in the last 3 months), and I'm setting new PRs on Strava nearly every day, PRs that were set with my road bike. Maybe I'm getting stronger, too, but my touring bike weighs ~30 pounds!

Don't assume it's slower just because it "feels" slower.
agreed, run 23c tires at 120 and it may "feel" faster, but it is not.
once I re-tuned my perceptions, i have found that fatter tires with high enough TPI and minimal tread are not much slower than my 25c GP4000s were. The advantages of the larger tires are worth it for me.
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Old 08-29-18, 04:22 AM
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Originally Posted by HTupolev
The Bon Jon actually did fairly poorly in that test IMO. It tested faster than most other tires in the website's touring category. It is not a touring tire.
If that test is accurate, the Bon Jon did VERY poorly.

The Vittoria Voyager Hypers outperformed it, they are much heavier and have puncture protection, and also cost half of the price... The Schwalbe Marathon Almotion did a bit better than the Hypers and those are even heavier, pretty darn burly touring tyres.

And of course the rolling resistance test didn't mention the horrible Compass tubeless stories.
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Old 08-29-18, 03:50 PM
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FWIW if you follow the ST thread, Tom A thinks there may have been inconsistent batches of tires, and he recommends the compass snoqualmie pass which has the same construction as the bon jon in a 44c. My experience with schwalbe marathons is even if they roll comparably, they are awful to actually ride on and had to be run at least 10psi lower than anything else of a similar width to even be bearable
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Old 08-30-18, 04:17 AM
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Trolling time: with any tire you will not fly like a bird. Why bother then?

On a serious note: this thread needs real life numbers. Not drum measurements.
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Old 08-30-18, 05:46 AM
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Originally Posted by Spoonrobot
The Microskin G-One AA is probably the fastest rolling 38/40ish knobbie other than the Compass Steilacoom. Gravel kings are on a slower level IME.
Which one is the AA, allround? Any info on the actual widths of the 35 and 40?

I like my GK SKs very much but I want to try something new because... Just because.
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Old 08-30-18, 07:27 AM
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How are there 4 pages of discussion parsing out this question?

Yes. A 40mm treaded gravel tire is slower than a 28mm Conti GP4K. Period. For all the reasons.
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Old 08-30-18, 09:10 AM
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Originally Posted by Spoonrobot
@Facanh yes I meant the all-around. I had the 40-622 model on rims 23mm wide inside and they were 41mm wide and 37mm tall. I only did a couple rides but they did not expand at all while I was using them.
Sweet, pretty much exactly like my 38 SKs! Wish the G-s came in 45mm too.
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Old 09-03-18, 06:37 AM
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Originally Posted by Barrettscv
I
The fastest rolling gravel tire is the 700x35 Hutchinson Override.
I doubt they faster than the Schwalbe G-one Speed 700 x 38c. Not quite slick, the whole tyre surface is made of 1mm knobblies.
I have the 29 x 2.35's and they are incredibly fast on tarmac. As fast as some road bike tyres for sure.
https://www.rosebikes.co.uk/schwalbe...e-2017-2655715
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Old 09-03-18, 07:06 AM
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Originally Posted by tablatom
I doubt they faster than the Schwalbe G-one Speed 700 x 38c. Not quite slick, the whole tyre surface is made of 1mm knobblies.
I have the 29 x 2.35's and they are incredibly fast on tarmac. As fast as some road bike tyres for sure.
https://www.rosebikes.co.uk/schwalbe...e-2017-2655715
I own both the Schwalbe G-one Speed and the Hutchenson Override. The Override is lighter, more supple and is nearly slick at the center section. The Hutchenson is faster.
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Old 09-03-18, 07:11 AM
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Originally Posted by Barrettscv
I own both the Schwalbe G-one Speed and the Hutchenson Override. The Override is lighter, more supple and is nearly slick at the center section. The Hutchenson is faster.
Whats its puncture protection like?
Snakeskin is very good, 3000 miles no puncture.
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Old 09-03-18, 07:20 AM
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Originally Posted by tablatom
Whats its puncture protection like?
Snakeskin is very good, 3000 miles no puncture.
I have not has a puncture with either. I'm 230 bs and I ride gravel in the Ozarks. I've passed many cyclist at these events who have punctured, some of them are on Schwalbes.

You should read this thread, if you need more information: https://www.bikeforums.net/cyclocros...res-print.html
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Old 09-03-18, 07:32 AM
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Thanks, nice thread.
2017 or 2018 (can't remember) Womans Gravel world champion one some races using Specialized Trigger sport tyres. Quite a bit heavier than the Hutchenson Override.
Horses for courses.
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Old 09-03-18, 09:05 AM
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Originally Posted by johngwheeler
I've just put on some Clement X'PLOR MSO 40mm clinchers on to my Giant TCX, for my first gravel ride. Previously the bike was in "commuter mode" with 28mm GP4000S2 tires.

But, boy, the 40mm treaded tires certainly feel a lot slower to me than the slick road tires on paved surfaces! I haven't done any timed tests, but it feels like a lot more work pushing these tires on the flat or up-hill. Sure, they have some tread, and weigh a bit more, but they feel a *much* slower. Actually, even slower than the very knobbly 33mm Schwalbe X-One cyclocross tires that came with the bike.

Is this transition from road to gravel tires normal? Is is a question of feel more than absolute speed? (I would expect maybe a 2km/h average speed drop from what I have read, but it "feels" like a lot more.

I guess I really need to do some timed tests, with both tires, but it's fairly hard to create a completely controlled experiment with identical conditions (especially without a power meter).

What has your experience been?
Depends on what you count as a "gravel" tire. If they have knobs, they are probably going to be slower. If they are just large slicks, maybe, maybe not. It depends on the tire.
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Old 09-04-18, 06:05 AM
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Originally Posted by Spoonrobot
@Banzai

@Facanh yes I meant the all-around. I had the 40-622 model on rims 23mm wide inside and they were 41mm wide and 37mm tall. I only did a couple rides but they did not expand at all while I was using them.
40-622 shows as the Marathon now. Did they ever have a 40mm G-One All Around?
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Old 09-04-18, 07:17 AM
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Drum rolling tests are a very accurate way to compare real life rolling resistance of tires....

....on your in indoor trainer.
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Old 10-13-18, 02:25 PM
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Originally Posted by johngwheeler
I've just put on some Clement X'PLOR MSO 40mm clinchers on to my Giant TCX, for my first gravel ride. Previously the bike was in "commuter mode" with 28mm GP4000S2 tires.

But, boy, the 40mm treaded tires certainly feel a lot slower to me than the slick road tires on paved surfaces! I haven't done any timed tests, but it feels like a lot more work pushing these tires on the flat or up-hill. Sure, they have some tread, and weigh a bit more, but they feel a *much* slower. Actually, even slower than the very knobbly 33mm Schwalbe X-One cyclocross tires that came with the bike.
They are. GCN did timed testing and found road tire are around 5-7% faster.
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Old 10-13-18, 07:55 PM
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Originally Posted by Spoonrobot
Drum rolling tests are a reasonable metric to compare tires in a controlled environment. Real world use is similar enough that a tire that performs well on the drum will often perform well on the road or gravel. This also applies to tires that do not perform well on the drum.
I often see it stated as established that drum roller tests are reliable approximation of real world results on real world surfaces, but Iíve yet to see where this is actually demonstrated.

And I will say up front that the results the Rolling Resistance guy gets for the Bon Jon Pass tires is a big red flag for me for that methodology.. Another test by Tour (a german mag) had them coming in as one of the fastest they tested on rougher surfaces.

And just riding them, I know first hand they are ridiculously fast rolling.
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Old 10-14-18, 09:55 PM
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Originally Posted by Spoonrobot
Are you able to see the link and graph in post 100? I mean that's it, that's the demonstration, on smooth and moderate asphalt the rolling resistance goes down as pressure increases to the breakpoint. It falls apart on gravel but there is no "good" testing protocol for loose surface riding, yet IMO. Everyone is extrapolating rough surface riding from what is essentially data from pavement. I suspect the major mountain bike XC tire companies have some very eye opening data but they're not sharing anything other than accidentally or very obliquely.

The biggest thing is that there is no breakpoint for the roller so it requires judgement and supposition to determine how relative higher pressures stack up compared to the suppleness of the tires. I wish BRR would have recorded sag values for all tires as it would make comparisons for off-road much easier. A supple tire is going to have a much higher real world breakpoint that a less supple/stiffer casing tire.

That is one of the many demonstrations, I recommend reading the Silca blog links as it goes into a lot more detail.

This paints a slightly different picture but it still very interesting: https://www.bikeradar.com/road/gear/...-tested-49101/



What methodology are you using? I have a smooth flat section of pavement and another section of consistent gravel that I perform "rundown" tests on. I ride to 16 miles per hour and then coast to a stop in the same position, record where I stop relative to a known marker and extrapolate from there. I make sure to only do the testing for tires on the same day and about the same time, it doesn't necessarily control for temp/wind but I can usually get it pretty good and then practical experience seems to be consistent with what my testing shows. It's coarse but it seems to work ok.

For example, I wasn't able to determine any difference between Grand Bois Hetres and Compass Baby Shoe Pass tires despite being different weight, size and construction. But it was shockingly obvious that Panaracer Gravel King slicks were much much slower despite having extremely similar characteristics as the BSPs.

I didn't like the Tour test because they ran the 35mm tire at 87 psi and the 25s/26 at 101 psi. That's way too high for the 35, the tire max is only 90 psi! They should have ran it closer to 45 psi. I think the pressure they used significantly overstates the resistance on the rough asphalt and understates the resistance on smooth asphalt.

Another interesting wrinkle is Tom Anhalt's testing. He's mainly focused on gravel with a triathlon bent but he seems to be finding a lot of interesting data on some of the Compass tires. You can see some of his comments here, they help add another well educated and robust voice to the discussion: https://janheine.wordpress.com/2018/...-in-the-world/

This is another good thread with Tom A. input - start at post 100: https://forum.slowtwitch.com/forum/S...63727/?page=-1

Personally I've also found Panaracer tires to vary widely in fit/finish which can have a profound effect on rolling resistance. I would really not be surprised if this ended up being the case for the BRR test, a bad tire, relatively. What's interesting is that Mr. Heine is probably well aware of this as he had a run of contract Grand Bois tires that ended up showing up and testing terrible despite close work with the factory to produce what he wanted. They were cleared out for a pittance and apparently forgotten.

Anyway, this is a very interesting topic for me as more than 1/3 of my yearly riding mileage is either timed events/races or rides 100 miles and longer. Having good fast rolling tires is one of the most important factors in my enjoyment of the sport. I have opinions formed by experience but generally try to keep an open mind and learn without too much ego.
I have read the links you posted to (in the past), except for the Slowtwitch discussion.

But I keep coming back to the same point I made before regarding using drum roller tests to rate rolling resistance in real world conditions.

In regards to the roller drum tests, the chart you link to as well as the study it comes from does indeed show that (up to a point) higher pressure gives lower rolling resistance for a given tire. But that is really it.

However, that is not really what people are most interested in here, or at least not what I was commenting on. What is of interest is comparing different tires and ranking them against each other, so people know which tires are faster than others in real world conditions. Some quantifiable metric would be more helpful, but ultimately we are interested in comparisons.

And with this in mind, that study is NOT demonstrating that a roller drum test will predict how tires will behave on real world surfaces, in a way that can be used for comparisons. The graph shows that even for pressures below the breaking point, real world RR values are different than roller drums, and the rougher the road, the bigger the difference. That in and of itself might not be a problem IF it could be established that the differential in RR between the roller drum tests and real world conditions were consistent for all tires, but I have yet to see such evidence. Until that is established, I do not think that claim that roller drum tests can be used for comparisons between tires can be defended very well. Perhaps I have missed such a study. If so I would be interested in seeing it.

I have read Tom A's ideas on why the roller drum test SHOULD be translatable to real world conditions, but again, not seen it tested.

I feel that conclusions around the roller drum experiments fall into a common trap that many areas of research do... that is, deciding data is useful based on the fact that it is accurate, precise, reproducible, and easy to work with. Nobody can deny it is wonderful data to work with. You can fairly quickly get wattage numbers that not only lets you compare tires, but you can quantify the differences, and even use the data for calculations..... However, that does not mean that the results answer the question you are interested in..

There is a saying I read once that goes along the lines of "too often we value what we can measure, rather than measuring what we value". Roller drum measurements are very accurate, precise, and reproducible, so we assign great value to them... however, what we SHOULD value is real world conditions, and give more weight to experience and experiments that measure that directly, even if the results are messy and often inconsistent. In other words, messy and inconsistent data measuring exactly what you want to know is better than clean and tidy data measuring something that may or may not be relevant.

So when you ask me what my methodology is, I don't mind saying that it is simple subjective feel..... but it is subjective feel of the exact thing I am interested in (how fast I roll on the tires). And i will take that over high quality results from an experiment testing something else for which the relationship to what i want to know is unclear.

For all the drawbacks, Roll down tests like you describe are IMO far, far more useful than roller drum tests for determining a rank order for tires RR in various real world conditions.... because it IS real world conditions. And if properly designed roll down tests on various surface conditions confirm the ranking that roller drum tests indicate (including Bon Jons) I would accept that.

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Old 10-15-18, 05:49 AM
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I don't race, not really interested in time while riding, but more out of curiosity I timed several routes where I live up to 5 times with the same and different tyres, from shopping trips with lots of cargo, to single track, and taking the average times,
my conclusion is very simple.
The rougher the conditions fatter tyres will always be faster.

I have tried many Tyers with the same routes.
In dry conditions, Schwalbe Big Ones are mega fast, and incredibly comfortable.
The Big Ones were faster than 2 gravel tyres (conti Cyclocross speeds and WTB Nano's 40c) no matter the terrain in the dry. Wet grass and mud, obviously the gravel tyres would win. But on gravel, unless you need to ride like a nutcase, the Big Ones do just fine in the wet.
I was using one as a rear tyre before it got real wet and muddy in here in the UK, for shopping/school trips. The 2.35 size and semi slick is a very fast comfy rear tyre.

But now its October, mud everywhere, thats not tarmac, a G one Allround 29 x 2.2 is going on the back, and Maxxis Ardent 2.4 or 2.35 Ikon on the front.
This combo is fast, secure and very comfortable for most riding.

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Old 10-15-18, 01:25 PM
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heat is energy lost

for the ones not OCD & in computer software writing..

Generically
the slick tires roll better on paved roads ,
the tread blocks there for dirt traction lose energy squirming as they roll ..
Friction creates heat.






....

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Old 10-22-18, 11:22 AM
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Wow, this is an OLD post. Still good for starting an argument though!!!

I anecdotally find that matching the depth of my tread to the roughness of the surface works out well. (roughly analogous to shoota's graph above).

I ride short knobs on shallow gravel and hard pack
I'll ride deeper knobs on softer and rougher terrain
Riding slicks in ideal conditions is amazing (i.e. velodrome), but deteriorates rapidly as the surface deteriorates)

Big Ones are easy to ride at 15mph. Above 20mph the weight (on rolling hills) and aero make them difficult to spin up in near race conditions.

Originally Posted by fietsbob
for the ones not OCD & in computer software writing..
Generically
the slick tires roll better on paved roads ,
the tread blocks there for dirt traction lose energy squirming as they roll ..
Friction creates heat.
....
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