Mounted clip on aero bars to my 27.5″ MTB with 1.8″ slicks (Weighs 10.5kg), got about a gear extra speed out of it and I was able to keep up with a roadie going at 50 km/h for a good bit.

We know that weight matters very little on flat ground (3.5 lb = 1 w difference), and where I live it’s flat, so I don’t see much advantage in getting a separate roadbike? My only problem now is that I spin out on 38:11 (in light tailwind ahem) gearing and can’t fit a larger chainring.

whats the question again?

Do you have corners there? or can you sit on the tri bars all the time? Do you need to brake?

Just wondering if people have benchmarked this setup against a roadbike. For braking the MTB would have the advantage I reckon with dialed 180mm BB7s and more tire traction. Not many corners.

All depends on position I would say. My mtb with clip on bars would struggle to keep up with my road bike. Never tried it, but can’t see how it could be as quick.

Aero is all about position. I would have to faff with seat post and spacers to get a good position. My road bike also has fast rolling tyres with latex tubes and aero wheels. My road position is set up for road use.

Sounds quick. Pics please . 🙂

Rather depends on the bike.

And the rider.

For braking the MTB would have the advantage I reckon with dialed 180mm BB7s and more tire traction.

Can you reach the brakes from the aero position though? Reckon I could be stopped before you got back to the brakes

Can you reach the brakes from the aero position though? Reckon I could be stopped before you got back to the brakes

Absolutely can’t. I guess where the roadbike would be a bit faster would be in the city with a lot of starts and stops.

I’ll take some pics this week. My bike is smallish for my height, so it mimics a road bike and the aero position I get seems decent (ideally I’d have aero clip ons that allow you to move the pads back).

@CaptainFlashheart looks comfy lol

I keep up with roadies all the time on my mtb and overtake in certain instances with knoblies on.

Infact i overtook someone the other week, it felt good however i then found his ride on strava, he was on the last bit of a 100mile hilly route and i was about 5 miles into my ride 🙂

Overtaking or keeping up with someone often doesnt mean much as there are too many variables to consider

My alloy 10.5kg cx bike with 35mm slicks is about 10% slower than my 7.5kg carbon race bike with 25mm slicks according to strava if that helps

Those tyres could be a drag (literally).  Fat MTB slicks are usually commuter tyres with loads of rubber and protection.  Road tyres should be supple and fast.

Absolutely can’t. I guess where the roadbike would be a bit faster would be in the city with a lot of starts and stops.

Yeah do prefer to be closer to the brakes when on the open road, or gravel, or anywhere really!! Throw in some gear changes and how long you can hold that position for, you can be on the roadie and be comfortable for a fairly long time, nobody ever looks comfy in that aeroposition 😉

Though wait until the roadie wants to drop you next time 😉

@CaptainFlashheart looks comfy lol

Must use be fairly comfy as that’s the bike used to set the 24 hr time trial record of 541 miles in 2011, iirc

Would a cassette with a 10t small ring help I wonder, if you’re spinning out and can’t go bigger at the crank?

But at 50kmph, aero would surely play a big part if its largely flat and you want to keep up for longer than ‘a good bit’.

Get a sperm helmet? 😉

That’s the kind of speed my mountain bike spins out at, when going down hill on a road, I wouldn’t be able to maintain it on the flat for any length of time.

My alloy 10.5kg cx bike with 35mm slicks is about 10% slower than my 7.5kg carbon race bike with 25mm slicks according to strava if that helps

Cool, now add aero bars to your cx bike and how much is the difference? According to this

up to 6.25:% (going at 50 km/h..) So it’s possible you could get get pretty close to your carbon bike.

@mattyfez think the helmet gains are a bit too marginal at around 2% (at 50 km/h.. again)..

I run the panaracer gravel slicks btw, seems pretty fast and light at 330g each.

Though wait until the roadie wants to drop you next time 

Hehe. well If I’m 10% fitter it seems he couldn’t if he wanted to! I did overtake him and he thanked me after i turned onto a side road. Either for letting him ride on my wheel or for getting the heck out of his way 😉

That image with the numbers on is great, just shows that the suit and helmet and position are the winners (although I do wonder how many riders need the TT frame in order to get the position,the BB height and vicious seat tube angle that gets your back flat) .

Do you have a background on the track? Because 50kph on your bike is 120rpm which would feel like a wild, uncontrollable effort to most people – riding smooth and fast at those cadences takes a lot of technique on the flat.

So not really sure what the question is, given your chainring limitations? Because belting round the place in position at 120rpm sounds like a horrible idea. Belting it round at a sensible cadence, OTOH, sounds fine if your MTB has a pretty forward position. So what’s the issue with this chainring? Surely it’s a HT of some description so it’s hardly a frame clearance issue is it?

If you get on with your mtb on the road then go for it. It’ll never be quite as fast as a similar road bike, but the difference won’t be huge.  Many years ago I used to do club TT’s on my mtb with slicks and aero bars for a while, got some decent times, but got better times on a road bike.

I still can’t see how you can get into such an aero position without doing some serious fettling, no way I can get my bars low enough without having to raise my seat post, which would compromise my power.

i notice the difference between my winter and summer road bikes, so much so that when we do chain gangs i prefer to use the “faster” bike all year to keep up. (25 miles at approx 21.5 to 22.5 mph)

With time and effort it’s probably possible to be as quick, but just stinking bars on a stock mountain bike I can’t see it. I think you’d have to have a power meter for both bikes, try multiple different positions and see what one takes less effort over the same course.

These pics may show what I’m on about regarding position, my Fuel Ex 29er, saddle is too high in this pic, new bike when pic was taken and still finding the best setup.

My road bike set up, both winter and summer bike setup side by side for comparative purposes….winter bike is black one at the back, has a slammed stem, just frame geometry not as racey as the White H1 Race Fit.

Winter bike without mudguards?

DAFUQ?

Good skinwalls, though.

Valves not lined up with tyres. Hang your head in shame!

Garry, I could do 40:11 with a BB spacer perhaps. Cheaper than a 10t cassette! Yeah problem is that I spin out ww tailwind.

Overall i think it’s cool how fast and goofy looking an mtb with tt bars can be, I’m a fan of one bike to do everything as it offers me more playtime (road bikes arent fun for tricks) whilst still letting me get from a to b quickly.

For me at the moment the one fun bike is the Canyon Grail, fast, aero properly geared and tough enough to do some fun stuff on. The gearing means 50kph is a sensible cadence, i’d be interesting to see how you are pedalling stably in that position and the sort of RPM needed

This segment was me and a mate with a tail wind

https://www.strava.com/segments/2356919?filter=overall

It’s slightly down has one small corner in it and nobody is topping 50kph average for the length of it we were smashing it hard on road bikes down there so good effort if your holding 50kph on the Trek for any length of time