Depends on the slicks and the mtb and all that really. I replaced my road bike with a fast hybrid boardman deal and it’s really not drastically slower except in bigger winds or up at the top end of speed. It’s long and flat so I’m in a relatively dropped position anyway and I can squash lower for spells if I want to. OK that’s not an MTB but you could achieve the same sort of fit and shape on the right mtb.

OTOH, on my mtb I sit upright like a sail with my arms spread like rigging, and trying to squash for aero doesn’t work that well and I can’t do it for very long. Though it’s probably still not that different to all those folks that buy road bikes then ride around on the hoods or flats sat bolt upright anyway.

Obviously I’m not a racer, but, I’d rather be a little slower/putting in more effort, in comfort. And that might be the tradeoff you’re basically talking about here, unless you can get the position right and get used to it. I’ll be honest, I got this totally wrong- I really thought it’d be a lot worse and I put a lot of effort and money into trying to make drops work for me, but it turned out the drawbacks were less than I’d imagined when I gave up and went flat.

My recumbent is most definitely slower than my road bikes. Partly friction and partly position (can’t get my heart rate as high). My mtb is a lot slower, largely due to it’s single speed.

A correctly set up road bike with an ability to spend a third of the time on the drops, will have a CDA about 10-20% smaller – hence you will be faster for the same power or need less power for the same speed. Less power means longer endurance. I’d expect about a 10% improvement at typical speeds (say 17 vs 15 mph).

And 25 mph for miles on end – oh I wish. I’d like to go under the hour on Sunday’s 25, and that’s a stretch goal.

Last night’s crit averaged 28 mph on a pretty flat course. Feeling it today.

I may have been a bit over enthusiastic there, strava says 22-23 :$

It is Cheshire lanes so about as flat as it gets. I’m not road KOM material round here though :/

I did a leg of the Cycle Against Suicide over here last year on my 456 Summer Season with Fox 36s over a similar distance (60m or so.) I altered it by putting on a bigger front ring (1×10) and got some road style tyres.

I was initially a little worried i’d struggle with pace and distance but it was far easier and slower than i thought. Obviously it wasn’t a race but i recall hoping they’d go faster as i was getting cold from going so slow.

I think it’s easily doable on a mountain bike but aero is everything. Take a road bike and use a big baggy jacket an shorts and your be less better off than a bloke on an MTB in bibs and fitted jersey.

Then you have the position on the bike. What’s comfy for that period of time?. I did 136 miles on a folding Dahon. It wasn’t a fast ride but the bike fitted so it was ok.

I did a comparison ride to work last summer. 40+ miles from mid sussex into London, once on the road bike and once on my 29er with 2.3″ tyres on. The road bike was only 10 minutes quicker and I was very surprised by that.

Where you wearing flappy clothing on both? It makes a HUGE difference.

Don’t be daft! My brother rode my road (well, CX commuter, actually) bike the other weekend. Managed the whole 7 miles
*taps irony meter in confusion*

Not sure where the irony is? That it wasn’t a road bike? It’s a CX which people say are even more uncomfortable than road bikes. (How often do we hear the “It’s built for sprinting around a field for an hour” line?)

Or the distance? No it’s not far, but he hasn’t ridden a bike for years and wanted to see if he could get on with drop bars so he knew what to looks for for his C2W purchase.

The point I was addressing was “after 5 miles you’ll be in agony”. 7>5 and yet no agony.

7>5 and yet no agony

Lol, you really thought I was attempting to be that specific?

7>5 and yet no agony
Lol, you really thought I was attempting to be that specific?

Well, yes, as you wrote it!

Like I said, I also did a decent commute and rides up to 100km on my Ribble with no special tweaking.

If the OP is 6’4″ and can only borrow a road bike from his 5’2″ mate then it’s not worth doing, but if there’s a bike of the right size that he can borrow for a test ride first then I’d say it was worth trying out, rather than writing off as impossible.

scaled – Member
I may have been a bit over enthusiastic there, strava says 22-23 :$

It is Cheshire lanes so about as flat as it gets. I’m not road KOM material round here though :/

That’s still astoundingly fast for solo riding on crappy lanes (I know, I live there) . 37kph is a bloody fast average, it’s about 1hr 4 mins for a 25mile TT on a normal road bike!!

Yeah, I assumed Molgrips’ “5 miles” was hyperbolic for amuseballs effect. 7 miles on a vaguely-fitted bike isn’t going to stress anything, really; it’s only about half an hour. Spending all day pedalling seated on a relatively short and upright mountain bike would be a different matter. Certainly would be for me, YMMV, obvs. I haven’t bothered working out how far the OP is planning to ride 😉

Average speed for a Tour de France rider on flat terrain is 25 – 28mph

TdY Stage 2 – not much up and down – 26.8mph with some fast mates and closed roads : https://www.strava.com/activities/561136295

I rode part of the Tour 2 years ago and created a segment that takes in 2 big climbs, Buttertubs and Grinton Moor. The KOM was 25mph over both climbs! I was utterly blown at a mere 15.9mph, which put me 140odd from 4540 folk so over 20 is solid!

https://www.strava.com/segments/7581128

If I could average 37kmph for a decent amount of time I’d be pretty chuffed. I can’t maintain that pace for long without a following wind or a downhill.

Where you wearing flappy clothing on both? It makes a HUGE difference.

I wore the same clothes both times. Not massively baggy but not lycra either, Gore stuff that’s fitted but not skin tight. I had to be seen in them at work so didn’t want to cop a load of abuse!

On my road bike I can get into a pretty decent position but the mtn bike is miles more comfortable over those distances, even when you’re trying to be aerodynamic. If it matters there’s only 2kg difference in weight between the bikes too. I thought the rolling resistance from the tyres would be the main factor. Road bike has 110psi 23mm slicks, mtn bike Spesh Purgatory/Ground Control (the heat duty grid versions).

Anyway, as I said earlier I was very surprised at the similar times. To the point where my road bike doesn’t really get used anymore.

TdY Stage 2 – not much up and down – 26.8mph with some fast mates and closed roads : https://www.strava.com/activities/561136295

…and a bucket load of Strava trophies and KOMs suggests you’re possibly a little faster than most 😉

On my road bike I can get into a pretty decent position but the mtn bike is miles more comfortable over those distances, even when you’re trying to be aerodynamic

No way! I find my MTB hideously uncomfortable on the road, all wrong. speed differential isn’t all that big (indeed my PB up Box Hill is on the MTB) but I’d never choose to ride my MTB on the road, over any distance.

and a bucket load of Strava trophies and KOMs suggests you’re possibly a little faster than most

That is the actual race you realise, not gravity-slave’s own activity…

There is predictably A LOT of willy waving on the thread.

FWIW I can happily tap out a 30mph average on my hardtail in the Dales over a 190 mile road route I did in 1995. I’m sure a road bike wouldn’t be much slower cos I’m awsums.

Not enough Gatsby on this thread yet, we’ve got a treat coming if he finds it though…

No way! I find my MTB hideously uncomfortable on the road, all wrong

Why out of interest? More limited range of hand positions but aside from that what makes the mtb significantly more uncomfortable on the road? Not poking, genuinely curious.

About 30 years ago when I was fit (and about 10Kg lighter) and had just come back from an extended climbing trip to the Alps I could manage 26-27mph on the flat for about four miles riding on my own. As the benefits of altitude wore off, the speed slowly dropped until I was in the 20-22mph range.

These days I’d be lucky to average 18mph without some serious training.

@no_eyed_deer Was it you we passed the other day when we were out bikepacking? 8)

Why out of interest? More limited range of hand positions but aside from that what makes the mtb significantly more uncomfortable on the road? Not poking, genuinely curious.

Everything to be honest. It’s too upright, the hand position isn’t natural (you have to hold on more than just rest your hands), it feels slower; moreso than it actually is, cornering feels odd and not as confidence inspiring (with knobblies). If you try and get aero it’s too short and you end up with very bent arms which is uncomfortable . It’s just unpleasant IMO.

stilltortoise – Member
TdY Stage 2 – not much up and down – 26.8mph with some fast mates and closed roads : https://www.strava.com/activities/561136295
…and a bucket load of Strava trophies and KOMs suggests you’re possibly a little faster than most

I get the distinct feeling Gravity-slave isn’t Bram Tankink, Pro Cyclist for Lotto NL Jumbo somehow 🙄

^lol I thought it looked impressive 🙂

EDIT: re-read gravity slave’s post and realised he wasn’t talking about himself and some mates. D’oh! 😳

I used to go out with the road boys at Uni on my mtb with slicks on back in the day, we’d average around 17-18 mph for ~40 miles, but I’d only sit in, taking a turn would have been yuk. This was on a far more head down, bum up mtb than modern mtbs. Oh I’d hold either side of the stem, so well away from the brakes and shifters!

You can’t use TDF speeds for anything, that’s bunched racing with a huge bunch, not remotely representative of what most peoples riding is like.

That’s why he used it, to get Scaled to have another look at his speed. I reckon Scaled should post his ride up here so we can marvel at his velociticitousness. 😉

Although if he really is that fast maybe I don’t want to look.

You can’t use TDF speeds for anything

Except perhaps for highlighting why you doubt a non-pro solo rider “…can tap out 25mph on the flat pretty easy for miles on end.” 🙂

EDIT beaten to it ^

I reckon theres quite a difference. My tale is as follows.

Theres a 15 minute steady road climb out of woolacombe bay. A few years ago i rode up it on my hardtail (26 with knobblies and no lycra) That evening i picked up my first road bike and did the same climb (no baggie shorts) the next day, taking nearly 5 minutes off my time.

Admittedly there might have been some new bike go faster beans in there but it was still significantly quicker.

Whilst my experience on a (shorter) and probably more shallow climb, where aero would be more of a factor is the opposite. No way is a road bike 1/3 faster than an average MTB.

regarding davidtaylforth’s restrained responses in this thread; iz disappoint.

No way is a road bike 1/3 faster than an average MTB.

I dunno. Depends on what you mean by average MTB. I’m way the hell slower on my Patriot up my local climbs even compared to my other MTBs, and it’s not even that heavy. On a road ride, it’d be ridiculous compared to the roadie. I think it’s more difficult to get power down in the upright position as well as being much less aero.

I’m doing big miles on both road, CX, MTB and fatbike. Road average is 28-30 kph, whereas a CX with fatter, softer tyres about 24-26, MTB about 22-24 and my fatbike is about 18-20kph average on smoother trails. Flat bars can be uncomfortable for long periods due to limited hand positions. Weight and rolling resistance become a bigger factor the hillier it gets IME. Getting lower on the bars whilst staying comfortable help on the road bike too – wide bars and long forks don’t help MTBs

Went out with my uncle over the weekend, me on the road bike, him on his new mtb. I was faster on the flats but he was faster on the climbs. May have had something to do with the 500 watt motor he had on his mtb though.

Well strava never lies! 😉

To be honest I might well have been trying harder as it was my first road ride but I still think the massively decreased rolling resistance of the tyres, bigger wheels and higher psi plus the stiffness and better power transfer of the road frame makes a big difference.

Plus the mtb ride I was probably in close to my lowest available gear on a triple for much of the climb. The lowest available gear on the road bike was 34/25 so there’s no option other than to grind that out which means you’re faster

Ps I looked it up…..

1.4 miles 428 feet

Times were 14.25 versus 9.24

It’s possible the wind was stronger as well I guess

Pps I’ve ridden the segment quite a few times since. Mtb times are always around the 14 minute mark, road bike times vary from 8.5 minutes to 11.5 minutes depending on the day and whether it’s my carbon roadie or my steel cx bike.

As an aside, I’ve consistently ridden my local road loops on said steel cx bike with clement ush mixed use tyres all winter. Average speed is usually around 14.5 mph give or take (lots of climbing) on my summer bike my average is almost always over 15.5 and often closer to 16mph.

It must be the bike that makes the difference since it’s the same routes and across lots of different weather conditions. Whether it’s the tyres (although putting 26 slicks on the cx doesn’t make it much faster) the weight (about 4kg difference) the more aero position or the difference in stiffness between carbon and steel I’m not sure. It’s likely they all play a part.

No strava factoids here , just personal experience riding road bikes and mountain bikes.
I would guess 25% faster on my road bike than my mountain bikes. Even a locked out full suss still bobs a touch. The tyres are draggy , the riding position not effiecient enough.
Then there is for me the biggy, psychology. Why hammer away on a 2.35 nobbly to get to a whirring 12mph , when on a Roubaix with Pacenti SL23 wheelset I would be doing 16mph/ 17mph?
So not just 25% faster , but 25% faster for alot less effort. Easier to accelerate , easier to maintain and carry speed after decents, out of corners.

I know I’m slower on my 29er on the road than know my road bike, having ridden the same segments at a similar perceived effort.

I did however hold off a pair of road bike pilots the other week while riding my 29’er on a long gradual incline that terminates in a 10% slope. All of can conclude front that is that neither of them were ‘scaled’ as s/he would’ve flown past me kicking up dust, stones and cow $h!t in their wake 😆

25% faster is about right for me based on strava differences between mountain bike and cx bike once up to a moderate to hard effort (round about threshold hr) speed. At lower speeds not such a difference

I’m with Singletrackmind on this…

My road bike is way more efficient and 17mph isn’t particularily taxing whereas my lurcher on slicks was….
I live mtb but for the commute I doubt if I’d go back tbh

DOD