Gravelking Slicks - alternatives??

47 replies · 5,397 views

ccand51997
265 posts
#21Oct 18, 2019, 3:27 PM
smoothmoose wrote:

Wow...you running mullet on your gravel bike? Alleviate toe overlap?

Really hard to measure tires objectively in real world conditions. I'm just got my new wheelset....almost 700g lighter than my stock wheelset. Will first swap my GK over to see if the rotational mass thing is noticeable or not, before deciding on new rubber. If I don't really notice a difference - maybe I'll go with heavier rubber.

No toe overlap issues, I just did not like the way a 29x2.2 steered. It was just too big. Mostly though, I wanted to get the front end down on my bike since it is a mtb frame and I run a shock. Add in some old bars with 170mm of drop and I get a nice aero position on the drops when I am going faster.

It is not easy, but tire testing can be done on the road if you have a power meter. I've been road testing with a power meter since back in 2004 and it makes a huge difference in cutting the crap and getting down to what really affects performance. In the beginning, I used it to test my aero position and equipment when I was doing multi-sport, but now I mostly use it to test tires. When I can get a nice tight set of repeats that hit right on the mark or 1-2 seconds above or below then I know I have a good data set.
As for you new wheels, it is not a question of whether it is noticeable, it is a question of whether it really improves performance. It will, but it is very tiny. I finally found the other page by Craig Willett.

biketechreview.com/reviews/wheels/63-wheel-performance

The whole thing is pretty enlightening but here is his summation:
So, what do all these numbers mean? It means that when evaluating wheel performance, wheel aerodynamics are the most important, distantly followed by wheel mass. Wheel inertia effects in all cases are so small that they are arguably insignificant.
How can it be that wheel inertial forces are nearly insignificant, when the advertisements say that inertia is so important? Quite simply, inertial forces are a function of acceleration. In bike racing this peak acceleration is about .1 to .2 g’s and is generally only seen when beginning from an initial velocity of 0 (see criterium race data in Appendix D ). Furthermore, the 0.3kg/0.66lb difference in wheels, even if this mass is out at the rim, is so small compared to your body mass that the differences in wheel inertia will be unperceivable. Any difference in acceleration due to bicycle wheels that is claimed by your riding buddies is primarily due to cognitive dissonance, or the placebo effect (they paid a lot of money for the wheels so there must be some perceivable gain).

In summary, wheels account for almost 10% of the total power required to race your bike and the dominant factor in wheel performance is aerodynamics. Wheel mass is a second order effect (nearly 10 times less significant) and wheel inertia is a third order effect (nearly 100 times less significant).

Anyway, this is not to say that the performance gain is zero, it just is not very high. In the first chart, it is interesting that even on the uphill only portion of his ride, lowering the front and rear wheel mass by 50 percent only resulted in a 3/4 of a percent difference in the power needed to go the same speed. That is akin to having a decent 1500 g wheelset and going to a 750 gram wheelset. That is more or less the loss in mass that you have (700g). Over the course of the entire ride, it dropped to .33 of a percent or about 1/3 of a watt difference. That is why light wheels really don't matter.

Sorry, that was long.
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clarksonxc
358 posts
#22Oct 18, 2019, 3:32 PM
bnystrom wrote:If you find that you can't feel a 700 gram (1.54 pound) difference in weight on your wheels, it really calls into question your ability to evaluate anything. The difference should be very obvious. Just sayin'...

Thank you. Thank you so much. Me (and to a lesser extent, Chas) were discussing a similar topic in another thread that I have been refraining from. The counter argument, from several folks on here, is that 1.54 pounds is a small fraction of the overall bike/rider system, and therefore an insignificant amount of weight. I have no response for someone who cannot feel this difference, and I have to assume they've never ridden a set of wheels that didn't come stock on a bike.
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bnystrom
459 posts
#23Oct 18, 2019, 7:58 PM
While it's true that the change in weight is a small percentage of the total package, changes in rotating wheel weight - especially in the rims and tires - makes a huge difference in the responsiveness of a bike. Anyone who disputes this either doesn't ride much or they're just not very perceptive. Perhaps long-term roadies like me are just more sensitive to it that newer riders or those who come from the MTB side. Who knows?
1
Masshoff
14 posts
#24Oct 19, 2019, 5:48 AM
GK Slicks in 38mm are just about the perfect year-round, all-purpose, fat roadie+ tire. Wide enough, light, supple, fast rolling, tough, easy tubeless setup, and conspicuously inexpensive compared to other brands. I have over 2000 miles on a set with minimal wear and only 1 puncture. Compass and WTB stop at 35mm, so no one else seems to be making anything comparable.
1
Craptacular8
6 posts
#25Oct 19, 2019, 9:54 AM
They may be the most reasonable, however Compass/Rene Herse does in fact make a slick 38, 44, and 50mm tubeless Road tire.
0
smoothmoose
210 posts
#26Oct 19, 2019, 6:19 PM
Masshoff wrote:GK Slicks in 38mm are just about the perfect year-round, all-purpose, fat roadie+ tire. Wide enough, light, supple, fast rolling, tough, easy tubeless setup, and conspicuously inexpensive compared to other brands. I have over 2000 miles on a set with minimal wear and only 1 puncture. Compass and WTB stop at 35mm, so no one else seems to be making anything comparable.

How much wear are you seeing? Below is the wear I am seeing at the rear after about 800miles (80% pathed, 20% gravel). Usually run 35psi and riding weight is 150-165lbs depending if I have my commuting gear. In the first picture the colored tread has worn down to the black casing. Just want to get comparables. It's starting to lose air quickly like 3-5psi/day.

Except for the wear, I have nothing to complain about.
0
Bt50
13 posts
#27Oct 20, 2019, 1:21 AM
I'm thinking/wondering the same thing!

How about the maxxis re-fuse? I'm leaning towards that over the gk (plus or not) slick.

Those are the same category tires right? Would one last longer and handle New Hampshire (cold, wet, windy, snowy, etc. ..) late-fall, winter, and early-spring (and colorado summer if they last that long) better?

Thanks
(Hopefully not a thread hijack!)
0
ljsmith
762 posts
#28Oct 20, 2019, 6:09 AM
clarksonxc wrote:

Thank you. Thank you so much. Me (and to a lesser extent, Chas) were discussing a similar topic in another thread that I have been refraining from. The counter argument, from several folks on here, is that 1.54 pounds is a small fraction of the overall bike/rider system, and therefore an insignificant amount of weight. I have no response for someone who cannot feel this difference, and I have to assume they've never ridden a set of wheels that didn't come stock on a bike.

If 1.5 pounds were added to your frame you would not notice except when picking the bike up. So there is some merit in the argument. However 1.5 pounds in wheel/tire weight would make the bike feel completely different. But keep in mind that if you drop 1.5 pounds in wheel/tire weight the bike may feel much faster, but unless you are doing a lot of climbing the actual gains are still small.
0
smoothmoose
210 posts
#29Oct 21, 2019, 1:30 PM
Bt50 wrote:I'm thinking/wondering the same thing!

How about the maxxis re-fuse? I'm leaning towards that over the gk (plus or not) slick.

Those are the same category tires right? Would one last longer and handle New Hampshire (cold, wet, windy, snowy, etc. ..) late-fall, winter, and early-spring (and colorado summer if they last that long) better?

Thanks
(Hopefully not a thread hijack!)

There have been a few suggestions for the Maxxis Re-Fuse here - but IMO it's not comparable as it is A LOT heavier (520-530g) than the GK (330g) - not really wanting to added another pound back on my bike. If I go heavy I think I rather try the Vittoria Terrenos.

However no mentions about the Maxxis Velocity AR (380g). The tread pattern looks more similar to the GK as well.
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Cmtgravel
83 posts
#30Oct 21, 2019, 4:16 PM
Big fan of Conti's as far as durability. Can't really speak about weight cuz i don't really pay attention to that. I used to run Conti Travel Contacts 37's on my gravel bike, and they rolled about as fast as the Conti Gatorskin 28's on my road bike. Very high mileage tire, damn near indestructible, smooth center w/ side knobs. Like all Conti's, they run narrow (my 37's measured just over 35 mounted), so i suggest sizing up. Downfall is theyre pretty slick in wet/muddy conditions.
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chas
1,305 posts
#31Oct 21, 2019, 4:35 PM
bnystrom wrote:While it's true that the change in weight is a small percentage of the total package, changes in rotating wheel weight - especially in the rims and tires - makes a huge difference in the responsiveness of a bike. Anyone who disputes this either doesn't ride much or they're just not very perceptive. Perhaps long-term roadies like me are just more sensitive to it that newer riders or those who come from the MTB side. Who knows?

Could be that they are riding a lower power level where responsiveness doesn't play that big of a role? For someone riding a steady state or accelerating casually, it might not make that much of a difference.

I spend a long time trying to get a bike as responsive as my track bike. That thing jumps so hard that I can spin my rear wheel at 20mph (probably pulling up to much on my pedals, lol). I love my gravelly bike because it is that responsive. Partially the frame (stiff in the right places), partially the over all weight, partially light wheels and tires - but the thing jumps when I accelerate hard. I kinda like a responsive bike. On the other hand, if I'm doing a long steady ride - responsiveness isn't going to mean much.
0
Volsung
878 posts
#32Oct 22, 2019, 7:32 AM
I mentioned Velocita ARs on my first comment. They're stock on new Giant Revolts. I have some but haven't mounted them. There's a guy on the MTBR gravel forum claiming he gets a flat on every ride using them, but it's only the one guy complaining.
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ccand51997
265 posts
#33Oct 23, 2019, 8:13 PM
chas wrote:

Could be that they are riding a lower power level where responsiveness doesn't play that big of a role? For someone riding a steady state or accelerating casually, it might not make that much of a difference..

In the Kraig Willett analysis link that I posted above, he made some comparisons during a 50 minute criterium where he averaged 323.33 watts. He compared a 32 hole spoked wheels vs a Lew front/rear carbon wheels and the difference went from 323.33 to 322.7 and .52 which combined for a .45 of a percent decrease in required power. To reiterate his point, " Furthermore, the 0.3kg/0.66lb difference in wheels, even if this mass is out at the rim, is so small compared to your body mass that the differences in wheel inertia will be unperceivable. Any difference in acceleration due to bicycle wheels that is claimed by your riding buddies is primarily due to cognitive dissonance, or the placebo effect (they paid a lot of money for the wheels so there must be some perceivable gain)."
The differences in wheel inertia were 100 times smaller than the weight.

323 is probably way more power than most people can manage so I doubt it is a high power/low power thing. As I named it above, it is a long held cycling myth that bike companies have no interest in killing because they use it to make money.
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chas
1,305 posts
#34Oct 24, 2019, 9:57 AM
Could be. So, its all rolling resistance then? I don't swap tires on wheels much, and I put my light tires on my light wheels, but something makes a difference. I'll say 100g doesn't make a noticeable difference, but 1.5lbs does seem to make a difference.

So, do aero wheels have a placebo effect, or is that more than weight?
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ccand51997
265 posts
#35Oct 24, 2019, 11:00 AM
Aero matters about 10 times more than weight, but for a discussion on gravel riding, I think it becomes a lot less meaningful because the average speed is lower, at least for me because I ride a lot of hills, sand and mountains. Plus, if you want a tire that rides well on gravel then it is not going to be aero. When I used to race tri/duathlon, I averaged between 23-25 mph and aero mattered very much. Now that I average like 11 mph in my gravel races with 6-7,000 feet of climbing, I don't worry about it much.

I have a 60mm deep front with rear wheel cover when I race on the road and it was a definite advantage, Like 1-2 minutes in a 40K. Body position matters a lot more, though; when I made a significant change to my arms and torso position it had more of an impact. Just a lot more surface area involved.
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Dino Sore
27 posts
#36Oct 27, 2019, 11:09 AMedited
Masshoff wrote:GK Slicks in 38mm are just about the perfect year-round, all-purpose, fat roadie+ tire. Wide enough, light, supple, fast rolling, tough, easy tubeless setup, and conspicuously inexpensive compared to other brands. I have over 2000 miles on a set with minimal wear and only 1 puncture. Compass and WTB stop at 35mm, so no one else seems to be making anything comparable.

Good to know. I sold one of my road bikes with the idea that I would use my new gravel bike as a back-up road bike (with a second wheel set and 28mm road tires). But now I'm thinking 32mm and tubeless. I've used the 26mm tubed version of the Gravel King on a road bike. It was a pretty good road tire, and handled dirt roads very well as long as I respected its narrow size (easy to pinch flat if going too fast on really rough stuff). The 32mm GK Plus looks interesting for a combination of paved and maintained dirt roads (I've got 40mm Donnely X'Plor MSO for dedicated gravel riding). As others have mentioned, there does not seem to be a lot of similar tires in the GK weight range.
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widerisfaster
253 posts
#37Oct 27, 2019, 8:55 PM
Dino wrote:

Good to know. I sold one of my road bikes with the idea that I would use my new gravel bike as a back-up road bike (with a second wheel set and 28mm road tires). But now I'm thinking 32mm and tubeless.
I have 32mm Compass Stampede Pass on my gravel bike for road duty. They are great. I have run the 35mm Bon Jon pas for 3000km, and I also put my 28mm tyres on for a week to compare. I think 32mm is a great size, still turns into corners pretty fast, and makes for a comfy ride.

For commutes and solo training, I tend to take the gravel bike with 32's over the road bike with 28's. For fast group rides I take the roadie with 28mm tyres and 50mm deep wheels to try and hang onto the fast guys.

0
NoCoGreg
512 posts
#38Oct 28, 2019, 1:30 PM
Masshoff wrote:GK Slicks in 38mm are just about the perfect year-round, all-purpose, fat roadie+ tire. Wide enough, light, supple, fast rolling, tough, easy tubeless setup, and conspicuously inexpensive compared to other brands. I have over 2000 miles on a set with minimal wear and only 1 puncture. Compass and WTB stop at 35mm, so no one else seems to be making anything comparable.
My observation on our tandem has been vastly different. The soft rubber of the GK picked up glass which eventually worked it's way through the protection belts and punctured the tubes. I lost count of the number of flats, maybe 7 or 8???

I've since replaced the GK slicks with Continental 4Season 32mm's and after several hundred miles of road riding no flats and they appear to be wearing slower than the GK slicks. The tandem has wide(ish) rims (32mm outside) which likely contributed the tire widths of 35mm for the 4Season and 41mm for the GK. Neither of these tires have been run on extensive gravel so I can't comment on the durability, but the GK endurance (miles before worn out) was what I'd expect of a road tire such as the Gatorskin.

That said, I just saw Panaracer came out with new GK+ slick and SK+ models so hopefully these will perform better as I really did like the feel of the GK.

Cheers,
Greg
0
smoothmoose
210 posts
#39Oct 28, 2019, 4:47 PM
NoCoGreg wrote:
That said, I just saw Panaracer came out with new GK+ slick and SK+ models so hopefully these will perform better as I really did like the feel of the GK.

Looks like the GK+ is an extra puncture protection layer which will help your problem...but probably doesn't help with the fast/early wear issues I've had.

I got the Vittoria Terreno Zeros on order and hoping the Graphene 2.0 compound is all that it's hyped up to be...and proven on their road tires.
1
chas
1,305 posts
#40Oct 29, 2019, 11:35 AM
Dino wrote:

Good to know. I sold one of my road bikes with the idea that I would use my new gravel bike as a back-up road bike (with a second wheel set and 28mm road tires). But now I'm thinking 32mm and tubeless.

That is what I did. I started out with 32mm 4-seasons which worked well tubless on my wheel. They do wear well. I switched to 32mm GP5000 TL which had half the rolling resistance and are very, very fast at speed (25-30). Can't say the 28mm gets me any advantage, other than I need to run them at higher pressure and because of that they "feel" faster and feel maybe more responsive. Quantitatively there isn't much of a difference.
1

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