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You think itís accurate that a gravel bike is potentially 20% slower than a road bike

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You think itís accurate that a gravel bike is potentially 20% slower than a road bike

Old 05-26-20, 10:40 AM
  #51  
fourfa
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Originally Posted by wgscott View Post
Jan Heine had a good article on this:

Are gravel bikes slower than road bikes?


https://www.renehersecycles.com/are-...an-road-bikes/

It discusses the GCN video posted above.
I didn't actually need to read this to know his conclusions would be:
1. If tests show dedicated road bikes are faster, those tests are stupid and irrelevant and wrong, racing is stupid
2. If any test shows gravel bikes are the same (or touring, or city bikes etc etc), see this is exactly what I've been saying about bikes for centuries

He has a right to his opinions, and I'm certain that some of his research and testing is valid. But he's not one to let objective reality interfere with his logic or the conclusions he's been advocating for a generation. So I find it tricky to tell the valid tests apart from the editorials.

Last edited by fourfa; 05-26-20 at 10:57 AM.
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Old 05-26-20, 12:23 PM
  #52  
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Just took the gravel bike out yesterday, 25 miles of pavement to get to Fairfax before dirt. Being not slow is nice so this doesn't take all day. Felt about the same as my aero race bike on pavement. I'm sure it must be a bit slower, but more like 2% than 20%
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Old 05-26-20, 01:23 PM
  #53  
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Originally Posted by mikehuangsd View Post
The difference is A LOT more than 20%, according to GCN:
I did a lot of testing last year. Answer - it depends on the tire.

A good gravel tire (I used Ramblers and G-One) was not a lot different than a "training" road tire. I used a Conti-4 seasons.

Most people don't ride a gravel bike at 30mph like GCN does. But I tried it. Rambler and the 4-season were similar, with a slight edge to the slick. at 30mph, those tires had about 60 watts of rolling resistance.

The GP5000 were only 25watts rolling resistance. That is like adding 30-35 watts to my threshold power. Try doing that by by training! It also lowered my heart rate by about 5bpm at speed. And, they just felt like I was riding on ball bearings (even though the road was crap).

Just riding solo on the road, yeah, GP5000 was about 8% faster - or about 1-2mph depending on my speed. Not sure why GCN needed so much power for the gravel tires. They should not have any where near that much drag - even at 30mph.

Yep the GP5000 are amazing. But comparing a gravel tire to a 4-season training tire, there wasn't much difference.

Last edited by chas58; 05-26-20 at 01:39 PM.
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Old 05-26-20, 02:02 PM
  #54  
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I just did my Tuesday morning loop on my SSCX bike, and less than 5% slower than a comparable effort on my carbon road bike. So that's the same course: 18lbs, 22 gears, 700x23s vs. 25lbs, 1 gear, 700x34s. Effort... similar (at least a similar stress score.)

Ended up 4 minutes difference over 50k, 1h41m for the road bike, 1h45m for the SSCX. I'm sure a lot of it comes down to tire-- there are some really slow tires out there. But geometry? Doesn't mean all that much to use mere mortals.
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Old 05-26-20, 02:49 PM
  #55  
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Originally Posted by chas58 View Post
I did a lot of testing last year. Answer - it depends on the tire.

A good gravel tire (I used Ramblers and G-One) was not a lot different than a "training" road tire. I used a Conti-4 seasons.

Most people don't ride a gravel bike at 30mph like GCN does. But I tried it. Rambler and the 4-season were similar, with a slight edge to the slick. at 30mph, those tires had about 60 watts of rolling resistance.

The GP5000 were only 25watts rolling resistance. That is like adding 30-35 watts to my threshold power. Try doing that by by training! It also lowered my heart rate by about 5bpm at speed. And, they just felt like I was riding on ball bearings (even though the road was crap).

Just riding solo on the road, yeah, GP5000 was about 8% faster - or about 1-2mph depending on my speed. Not sure why GCN needed so much power for the gravel tires. They should not have any where near that much drag - even at 30mph.

Yep the GP5000 are amazing. But comparing a gravel tire to a 4-season training tire, there wasn't much difference.
I am the point now I'll take comfort over speed. but I also don't enjoy rides that i have to work for it. Meaning if I have to put in that much effort then I better be going faster.

I did however choose the RDO over the 853.... so it's not all about comfort. (part of that choice was standover) though. I figured I could run a gp5000 32c, Jon bon 35 barlow pass 38, snoqualmie- 45 riddler, or 42 resolute also.

A 650 switchback hill is very tempting but I've heard of them ballooning. Niner says 2.0 for the 650b so possible.... I am really undecided, and I'll also be seeing a huge mix of surfaces with this bike
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Old 05-26-20, 07:21 PM
  #56  
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On similar routes, I'd cruise at 32kph on my TT old titanium bike, and about 29kph on my gravel bike (ie. easy 6 RPE efforts )
Just based on that, its about 10-8% slower.

That said, my gravel bike is at least 3kg heavier with a maybe a 100g heavier disc wheel (TT bike has rim brake wheels)
Not to mention the aerobars.
So not fair comparisons, though in real world situations a gravel bike does some things the TT bike can't, so they are what they are.
With a lighter gravel bike with 28mm tires, maybe that 10-8% difference will shave down to 3-5%?

The marketing hype on wider tires to me only holds weight if a lot of the roads are really bad.
I have noticed that I sail thru such sections on 42mm tires compared to other riders if they are on roadbikes.
There is just too much bumping up/down with very high pressure tires that there is a loss of fwd traction. (even more so it its bad road + climbing )
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Old 05-28-20, 02:49 PM
  #57  
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Originally Posted by Metieval View Post
I am the point now I'll take comfort over speed. but I also don't enjoy rides that i have to work for it. Meaning if I have to put in that much effort then I better be going faster.

I did however choose the RDO over the 853.... so it's not all about comfort. (part of that choice was standover) though. I figured I could run a gp5000 32c, Jon bon 35 barlow pass 38, snoqualmie- 45 riddler, or 42 resolute also.
My initial impression of the 32c GP5000 (besides the easy speed) was that it was as comfortable as my 40mm gravel tires - although that is somewhat pressure dependent (obviously I can go lower with the 40mm tires if I want to).

Since this year, group rides are out, I've been riding the 40mm tires - cause why not. Kinda like the way the Terra Speeds look on my bike. But certainly when I'm back to commuting and fast group rides (where I'm the only one not on a road bike), I'll choose the easy speed.
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Old 07-27-20, 08:40 AM
  #58  
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Wonít make a difference to most people, unless theyíre elite roadies.

Then youíll need the lightest, fastest road bike money can buy. Irrelevant to 99% of the population.
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Old 07-27-20, 08:49 AM
  #59  
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Originally Posted by fourfa View Post
I didn't actually need to read this to know his conclusions would be
That pretty much speaks for itself (perhaps in a way you did not intend).
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Old 08-02-20, 03:41 PM
  #60  
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Iíve been asking myself this a lot. I really want to love my Ď16 Kona Roadhouse even just half as much as I do my Ď86 Trek 770. I donít.

Tires do make a ton of difference.

my ďgravelĒ bike has become the Roadhouse when itís with 32c Paselas. It has a 72 deg headtube

my Roadie is the Trek with 25c Corsas. It has a 74 deg headtube. Also itís a lot more flexible.

I havenít yet looked at the trail difference to totally say that geo is doing something to me. Their stack and reach arenít far off. Iíve done everything I can to make the bb-bars-saddle relationship close to identical between the two bikes.

Even with the Corsas on the Kona, no matter how hard I hammer it, how much time I spend in the perfect tuck, I am slower on it than I am on the Trek.

Getting off of a 100miler on the Kona and being ready to pass out and just taking the beat up old Trek to grab some groceries, I feel ready to hammer out another hundred miles. If I do the opposite, I find Iíd rather walk to the store.

I think that some of it is the tires, but more of it is (I donít know which) in either the modern forkís extra stiffness fighting back at every pedal stroke or the slack geometry that asks your legs ďwhatís the rush? Why not sit up and ease back for a bitĒ

20%? I donít think itís that much. My trying-to-snap-the-cranks-off-on-the-Kona times are only about 2-5% longer than my having-fun-on-the-Trek times on the same routes. Iíd sure love to experiment with some powermeter pedals to have an answer before I give up on the Kona and try having Waterford build me a wide-tire-clearing copy of my Trek.

Last edited by hsuBM; 08-02-20 at 03:48 PM.
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Old 08-02-20, 07:21 PM
  #61  
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I ride a road-plus bike, going for safety over max speed: if I hit an unexpected road anomaly on my 48mm tires at 30psi, I'm unlikely to lose control; while hitting the same thing on a 23mm tire at 110psi may lose control. If you lose control, you probably injure yourself, with the broken clavicle being one of the common injuries. While you are recovering from the injury, you are losing performance at an exponential rate. So from my perspective, if the road-plus bike has protected me from crashes that I would have experienced on a typical road bike, then the road-plus bike is the faster bike (because it allowed my engine to grow stronger).
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Old 08-11-20, 02:44 PM
  #62  
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If I could switch my 46 large (gravel) chainring to a 50 or 52 and my tires to GP5000 tubeless with very little effort, I wouldnít own a road bike. The 46 with shorter tires spins out way too soon.

Alas it is pretty easy to just grab the bike I want to ride and yeah, the road bike with 32mm tires is considerably faster on the pavement than my (much more expensive) gravel rig with 45ís. I donít like going slow.
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Old 08-12-20, 07:18 AM
  #63  
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Originally Posted by tyrion View Post
A gravel bike is only 17% slower than a road bike.
I heard it was 16.2% slower.
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Old 08-12-20, 07:42 AM
  #64  
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As I've illustrated previously, it is in fact 8% (or less.)

Though with my current set of tires (the 700x30 WTB Exposure have been replaced by 700x40 Conti Terra Speed) the most recent split on my 50km loop was just 2 minutes, the fat tires taking just 9 more watts.

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Old 08-12-20, 10:15 AM
  #65  
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Again, its fun riding my bike in a semi-competative road ride. 32mm GP5000 tires with tons of clearance, when everyone else is on 25mm 100psi road tires on road bikes. I get comments on how I'm a lot faster than I look (especially when sprinting to the front of the pack at 30mph), and people squeezing my tires to see how much pressure is in them (50-60psi). Personally I think on our crappy roads, this bike is faster than a pure road bike on 25mm tires.


If I could switch my 46 large (gravel) chainring to a 50 or 52 and my tires to GP5000 tubeless with very little effort, I wouldnít own a road bike. The 46 with shorter tires spins out way too soon.
.

I don't own a road bike. Its easy:

I'm riding the gp5000 in the rear all summer/fall. I do put a fatter tire on the front if I'm going for the rugged stuff (its worth it to get a second set of wheels for me).

I don't know how to spin out on 46t chainring. I can pull hard at 40mph, and above that its much more efficient just to draft or tuck.
(but hey, I'm a trackie. I'm not spinning out on the oval until I'm going over 40mph with a 49x15, lol)
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Old 08-12-20, 01:29 PM
  #66  
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Originally Posted by chas58 View Post
I don't know how to spin out on 46t chainring. I can pull hard at 40mph....
You are definitely a spinner!! 46X11 is 120rpm @ 40mph. I'm whipped just thinking of it
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Old 08-12-20, 02:16 PM
  #67  
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put efficient rolling slick tires on it and see if it feels faster,

set up a time trial course & compare times with you on both bikes?
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Old 08-14-20, 09:40 AM
  #68  
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Originally Posted by shelbyfv View Post
You are definitely a spinner!! 46X11 is 120rpm @ 40mph. I'm whipped just thinking of it
Yah, I'm not very strong, lol. Gotta get power from speed. I top out about 140-150. But in a group or solo ride (non sprint situation) I'm coasting above 35. Pedaling above that speed is messing up my airflow and aerodynamics, so I had better be putting out a lot of power to make it worth my while.

(I did do a group ride fixed gear once, but doing 180rpm down hill isn't something I ever want to do again, lol).
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