‘Gravel’ bike vs road bike on the road – speed

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  • ‘Gravel’ bike vs road bike on the road – speed
  • Premier Icon charliemort
    Subscriber

    there seems to be a few threads about this

    rode by Salsa Cuthroat to work today and compared my time to road bike times. It’s on 40mm Schwalbe G-One’s. Basically a 20 mile pretty flat ride

    road bike distances and times – distances vary a bit I guess through where exactly I start / stop the Garmin:

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    <td class=”xl63″ style=”height: 14.5pt; width: 48pt;” align=”right” width=”64″ height=”19″>17-Oct</td>
    <td style=”width: 48pt;” align=”right” width=”64″>19.96</td>
    <td class=”xl64″ style=”width: 48pt;” align=”right” width=”64″>01:17:31</td>
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    <td class=”xl63″ style=”height: 14.5pt;” align=”right” height=”19″>19-Oct</td>
    <td align=”right”>20.04</td>
    <td class=”xl64″ align=”right”>01:20:09</td>
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    <td class=”xl63″ style=”height: 14.5pt;” align=”right” height=”19″>02-Oct</td>
    <td align=”right”>20.06</td>
    <td class=”xl64″ align=”right”>01:18:59</td>
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    <td class=”xl63″ style=”height: 14.5pt;” align=”right” height=”19″>31-Oct</td>
    <td align=”right”>19.7</td>
    <td class=”xl64″ align=”right”>01:17:47</td>
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    Salsa – I think it was recording time from beginning of ride, but not distance as Garmin was struggling to pick up satellites
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    <td class=”xl65″ style=”height: 14.5pt; width: 48pt;” align=”right” width=”64″ height=”19″>08-Nov</td>
    <td class=”xl66″ style=”width: 48pt;” align=”right” width=”64″>19.53</td>
    <td class=”xl67″ style=”width: 48pt;” align=”right” width=”64″>01:19:40</td>
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    got to say I was surprised, I thought it would be much slower. As it is, 2 or 3 minutes over 1 hr 20 doesn’t seem a lot. Obviously not very scientific but I’d say my effort levels were similar

    Premier Icon hardtailonly
    Subscriber

    Yeah.

    Insert-hyperlink-fail I’m afraid!

    I don’t have a proper road bike, but don’t notice my average speeds decreasing too much when running wider, knobblier (35 or 42mm) tyres compared to 28mm slicks, certainly over a 13km commute. Over a 50ish k lumpy road ride around here, I’d expect around 24/25kmh on the knobblier tyres, and 26-28kmh on the slicks.

    Increased weight of bigger tyres has an impact on climbing. And the 47mm tyres I currently have on are either noticeably slower rolling and/or cause more aero drag.

    cynic-al
    Member

    Obviously not very scientific

    So much so it’s not worth discussing.

    Increased weight of bigger tyres has an impact on climbing. And the 47mm tyres I currently have on are either noticeably slower rolling and/or cause more aero drag.

    See above, also the weight matters **** all, nor does the aero unless you’re doing 25mph+, they may well roll differently (they are different presumably, so all bets are off) but you won’t notice that either.

    Basically unless you’ve made sure wind is the same, tyre pressure, and used a power meter, the comparisons are too far out.

    Bit yes a gravel bike doesn’t need to be much slower than a road bike .

    Premier Icon hardtailonly
    Subscriber

    See above, also the weight matters **** all,

    Really? So 2x600g ish tyres compared to 2x350g ish tyres won’t be more hard work (and slower) when going up hills?

    Premier Icon rOcKeTdOg
    Subscriber

    g-one isn’t really a proper gravel tyre though, hardly any knobbles on it so it’ll always roll better than something off road capable like a resolute

    Premier Icon Kryton57
    Subscriber

    Over a 50ish k lumpy road ride around here, I’d expect around 24/25kmh on the knobblier tyres, and 26-28kmh on the slicks.

    My own experiments reveal very much the same.

    Premier Icon charliemort
    Subscriber

    well cynic-al – if you’re not interested don’t read it then.

    I copied in from excel and it didn’t work……….

    road bike

    1:17:31

    1:17:47

    1:18:59

    1:20:09

    gravelly thing

    1:19:40

    I hadn’t really looked at times before so wasn’t chasing a time on gravel bike thingumy. I thought it would be towards 10 minutes slower

    tpbiker
    Member

    I’m 45 sec or so slower For same power up a 5% 1.3 mile hill between a caad x with 35mm gravel King sks and my carbon roadie with carbon aero wheels. There is around 2.5 kg in weight difference. Chhange the sks to road tyres and caad x is about 25 sec slower on average.. Not taking into account wind.

    Over entire ride difference is around 2mph on average, although not really comparing power in that case, mainly perceived effort.

    taxi25
    Member

    As it is, 2 or 3 minutes over 1 hr 20 doesn’t seem a lot.

    I’m 45 sec or so slower For same power up a 5% 1.3 mile hill

    Faster, slower it doesn’t really matter if your out for a ride on your own, what does it matter ? If Strava’s your bag you’ll only be trying on the fast bike anyway. But riding wirh others 2-3 mins per hour or 45 secs on a climb is a lot of energy you need to find to keep up. If I’ve got a choice I normally pick the fastest bike for a particular job, for me antway thats where the fun is.

    kerley
    Member

    My speed over 1 hour long loops differs by up to 5 minutes on the same bike just down to how good I feel on that day, how windy it is, how hard on I am trying on certain parts of the ride etc,.

    If I used a gravel bike on the day where I record a good time I would think the gravel bike was faster.  If I used it on a day I was slower I would think the gravel bike was slower.

    All things being equal (wind, temperature and your own performance) the road bike will be quicker but not by very much.  Because the lighter weight, the more aero, the faster tyres all add up (even if the overall difference is still minimal)

    Premier Icon w00dster
    Subscriber

    Similar to TP biker, a good 2mph difference. That’s not a gravel bike with an upright position like the Salsa either. Trek Domane running 33mm knobbly tyres.

    My road bike is a Canyon Aeroad, about 2kgs lighter. The perceived effort is noticeably different.

    My commute is about 11 miles, reasonably flat. My commute/gravel  bike is no slower over that distance than my road bike despite a good 5 or so KG’s difference in bike weight plus back pack of clothes on my back and the drag of the full mudguards. It is significantly more comfy though. I’m sure there would be a difference over a longer distance though – it’s probably a small percentage less efficient, so not enough to show over a short 11 mile commute, but over a longer and hillier ride it’d soon start to feel more sluggish than my road bike.

    Premier Icon Kryton57
    Subscriber

    Faster, slower it doesn’t really matter if your out for a ride on your own

    Indeed, but I suspect that this thread exists because there were prior threads stating “Gravel bikes roll just as fast” or “I can sit in the club run just the same”.

    The answer is there are lots of variables but a heavier, less aero, bigger tyre’s more rolling resistance bike will be slower at some point in a ride, its basic science.  It may pick up elsewhere – e.g. I find my gravel bike feels more confident downhill than my Road bike.  That could be real or perceived.

    Just enjoy them both for what they are.

    prawny
    Member

    I don’t think there’s a huge difference in overall speed between my grovel bike and my roadie, but I really notice the difference at the end of the week.

    My hack isn’t as inspiring to ride fast, so generally I don’t,but after a week on it I am spent, whereas on the Vitus I’m tired but not wasted.

    Compared to my road bike with standard geometry and 23mm tyres (remember those?), my ‘gravel’ bike is positively horrendous to descent a twisty mountain road on.  It is not very nice to climb on, either – last time I rode the same climb back to back on each bike, an hour and a bit on the roadie, the gravel bike was an exercise in frustration with its 38mm tyres and gappy 1×11 cassette.  But the descent was a lot more fun, turning off the road and taking  the singletrack and fire roads!

    daern
    Member

    I’ve got a particular 45 minute lunchtime loop that I do from work and I’ve actually experimented with it, riding both a 25c road bike and a 35c gravel bike (albeit, shod with Schwalbe G-Ones which aren’t exactly knobbly!) I’ve done it a fair few times, taking it easy and thrashing myself to bits, as well as with various wind directions. My fastest gravel time is only a couple of minutes slower than the fastest road time, but I am pretty confident that I couldn’t close that gap – well, not unless I got fitter and then the road bike would go quicker too!

    What is, perhaps, more useful is that when I ride this with various colleagues, either of the bikes is fine and, tbh, it doesn’t really make a difference to me which one I am on as it’s a relatively short ride, so most of the time I don’t worry about it!

    Premier Icon charliemort
    Subscriber

    As others have said – I think on a big hilly ride the road bike would be less knackering, if not a lot faster

    cynic-al
    Member

    Really? So 2x600g ish tyres compared to 2x350g ish tyres won’t be more hard work (and slower) when going up hills?

    All other things being equal, the difference is 500gm, so say +~0.5 of of gravitational losses only.

    if you’re not interested don’t read it then.

    I get that the differences seem big,but my point is that there is some background stuff (science) going on that is actually what matters/makes the difference, but many CBA thinking about that. See also newspaper headlines and politics.

    Faster, slower it doesn’t really matter if your out for a ride on your own

    There are folk on here talking about strava, FTP, aero wheels, and they don’t even race or seemingly ride in groups!

    Premier Icon facian
    Subscriber

    GCN did a semi-scientific test of road vs gravel (obviously there are still variables but same day, same location and using power meters), including climb & descent with road/gravel bikes as well as then swapping wheels. The general trend was all pretty much as expected for the two bikes, as it is here but the differences were pretty small:

    Ultimately some people like geeking out on the numbers/technical differences as much as riding, and some don’t care at all. I’m somewhere in between where I’ll look at all the technical/geometrical differences in bikes when choosing one, and then ignore it and buy the one I like the look of!

    Edit-linked the playlist rather than the actual video!

    philjunior
    Member

    I can think of roads where a gravel bike (with nice fast rolling fat tyres) would be faster than a road bike.

    But generally yeah, couple of minutes over an hour or so sounds about right. I reckon I lose about 1mph between the road bike and the normal commuter (slower tyres, a bit more upright) and about the same to my MTB if I have fast tyres on it (more upright, don’t have the gears, certainly not tightly packed around cruising speed).

    I reckon I could get the commuter very close with the right tyres, but then I’d lose it all when I put luggage on.

    I think the other main factor here is the breadth of the gravel bike spectrum.

    Take a carbon gravel bike with not too much clearance, say a GT Grade, with light slick 32-35mm tyres like WTB Exposure of Panaracer GK slicks, and it’ll not lose much if anything to a dedicated road bike, especially if the road is bumpy.

    Take a gravel bike that tends more towards the monstercross end of the spectrum, with 45mm WTB Riddler’s or something, and tarmac roads are going to be a fair bit more work.

    cynic-al
    Member

    Yup, it’s basically about the tyres and aero.

    Premier Icon Ben_H
    Subscriber

    It depends on what sort of roads you are covering.

    I have a favoured back roads route to work (c.28 miles), which includes a big initial uphill, then down and along rough B-roads before finally joining a flat cycle path.  I do it often enough, along with a general 28-mile commute round trip even more often, to be able to control for all the other variables.

    In dry weather, I’m noticeably quicker uphill on my Trek Emonda (7.5kg, sharp angles, caliper brakes, 25c) than my Shand Stooshie (9.5kg, relaxed geometery, mudguards, discs, 28c – basically a gravel bike).  The sharper the ascent, the quicker I am on the Emonda.  However, in the wet, on downhills or on poorly surfaced roads I’m often quicker on the Shand.  Over the whole ride I’m about 2-5% quicker on the Trek, but only in bone dry weather and the advantage is made over short distances.

    You have to remember that a good road race bike puts you in the position to put out more effort.  You may not want to ride like that all the time, though.

    What my Shand does is help me cover longer distances in all weathers, at 95% of the speed.  It’s a bit like as a GT is to a sports car.

    Premier Icon molgrips
    Subscriber

    Really? So 2x600g ish tyres compared to 2x350g ish tyres won’t be more hard work (and slower) when going up hills?

    Barely.  Rolling resistance would make more difference I’d say.

    Anyway.  I have recently been riding my commuter on long distance rides on flat smooth terrain.  It feels fine to ride, however it is definitely (subjectively) harder to sustain speeds over 32kph.  I think that on flat ground the less aero position and bike itself start to count because on flat ground you are really only fighting aerodynamics.

    tpbiker
    Member

    The other variable I reckon is the temperature. I am noticeably slower when it’s 6 degrees than when it’s 20 degrees for similar power… Maybe up to 1mph difference on same bike over a 2 hr ride.

    And since I’m far more likely to use the heavier winter bike when it’s cold, then that just adds to the drop in speed.

    It’s not just one thing, there are loads of elements to consider but as kryton says basic science tells you a lighter, more aero bike, with less rolling resistance will be quicker.

    On your own, as Al says, it doesn’t matter. But I don’t agree that you need to be a racer to care. I often ride with my faster mate.. I need every possible advantage to keep up otherwise he’s waiting for me at top of every hill. Likewise I go out with my slower buddies and it makes more sense to take the slower bike so I get same workout and can still ride with them without leaving them behind

    Premier Icon mikewsmith
    Subscriber

    Well my anecdotal evidence of Tour of the borders, and chasing the the Tour of Britain was you get a lot of funny looks when you motor past somebody on 40mm Schwable G Ones, then explain they roll really well, slap them on a nice aero frame and build it up light and it will motor just fine, maybe slightly more work but it does handle the shit roads much better

    cynic-al
    Member

    definitely (subjectively)

    Phrase of the debate!

    I think that on flat ground the less aero position and bike itself start to count because on flat ground you are really only fighting aerodynamics.

    Depends on lots of factors, are you fit enough to make aero the factor? Slow tyres could affect this, also aero.

    Perfect example of why so many opinions are meaningless

    kerley
    Member

    The other variable I reckon is the temperature. I am noticeably slower when it’s 6 degrees than when it’s 20 degrees for similar power

    I have noticed that but put it down to me be in worse shape over the winter due to riding lower distances.

    But to me the a big factor is just how I feel.  Lats Sunday felt great and was fast compared to many runs over one of the loops I ride.  Today felt slow from the off, backed up by first hill I hit feeling awful and my ride was slower.

    My gravel bike is 1 or 2 kmph slower than my road bike with 32mm slicks on it, mainly as its more upright in position over a 50km or so ride. With 38mm G one allrounds its hard to say as I take it offroad on those rides so its slower I would guess the road bits are 5kmph slower. Although its hard to say as I tend to blast the offroad bits and relax on the road bits, whereas on the roadbike or on road only rides I tend to ride in a more controlled even manner.

    The gravel bike makes me smile more when I go offroad though!

    Premier Icon ransos
    Subscriber

    Compared to my road bike with standard geometry and 23mm tyres (remember those?), my ‘gravel’ bike is positively horrendous to descent a twisty mountain road on.

    I didn’t find my Arkose too bad descending mountains in the Black Forest in the summer. A touch slower through the corners, but I still managed 90kph, and the disc brakes came in handy.

    I’ve found the same, my commute is 25miles and on the road bike takes 1h30, on the SS MTB its only 1h45-1h50 despite being limited by bearing and taking an off road detour.

    What makes it slower is a little bit of everything, mostly aerodynamics IMO, but it’s not so slow that it matters when riding solo.

    Depends on lots of factors, are you fit enough to make aero the factor? Slow tyres could affect this, also aero.

    Aero matters at all speeds, unless youre riding uphill or in deep mud its the primary source of drag at anything more than a slow jog. And  typical mountainbike position is as subtle as a brick through a shop window compared to a road bike (or even better a TT position).<span style=”font-size: 0.8rem;”> </span>

    <span style=”font-size: 0.8rem;”>I you dont believe that try rideing a singlespeed, amongst other things it forces you to think about anything that makes you quicker other than pedaling. I can just about keep up on the road in a mixed group of CX bikes on an MTB geared at 32×14. Once its on the verge of spinning out a quick tuck downhill to regain some breath then sprint up the next incline and repeat. I can even pull the same trick on the fat bike. Just built a drop bar 29er as an experiment to see how much quicker it is on non technical stuff where pedaling is more important than technique.</span>

    dirtyrider
    Member

    2017 Tour of the Peak – Giant Defy (700c x25mm) – 7:58:00 moving time

    2018 Tour of the Peak – Mason Bokeh (650b x 47mm) – 8:21:14 moving time

    only same ride ive done on different bikes

    cynic-al
    Member

    TINAS I was responding to gravel bike Vs road bike, ans the DIFFERENCE in aero being significant – I expect that requires more than a jogging pace, but I’m happy to see your workings 🙂

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