Is a Roadie with wider tyres still faster then a MTB with slicks?

Question

I need a new bike, but I´m in a dilema on which too choose, because my rides involve 4 kinds of pavement: smooth cycle ways, cobblestone, ok city roads and rough city roads.

Was thinking just to keep doing what I have been doing till now, get a new MTB, a BTWIN rockrider 500(for those in the US, BTWIN is a brand sold in Europe that as nice groupset parts for the price) and fit it 26 slicks.

But then on the site saw they have some flat bar roadies: http://www.btwin.com/en/road-bikes/fitness-road-bikes/18701-triban-520-fb-road-bike-black-red-white.html

So I wonder... If that roadie was fitted with 700x32 slick tyres would it make it rideable on cooblestone/cracked pavement without the risk of damaging the wheels?

And maybe the most important, would it loose much speed compared with the original tyres(700x25) on the smooth roads? Would it be just about as fast as the "slicked" mtb?

And please, no need to tell me to get a city bike. From what I have seen, they are even heavier then MTBs, and in my prices budget I can get a Btwin MTB with Sramx4 or Acera. While urban ones only have the tourney.

Answer 1

I'd recommend a Cyclocross bike (also called CX). That's a robust road bike frame, configured to accept tyres up to about 40mm wide. You won't need 40mm unless you're doing proper off-roading, but a nice 30-35mm file tread such as a Specialized Trigger or Schwalbe Sammy Slick will run nicely on smooth pavement, will handle cobbles and bad pavement, and will also handle mild gravel/dirt.

I have a setup like that, and the thing that I love about it is that I can ride pretty much anywhere from road to gravel to bike paths to rail trails to single track (except for MTB trails with lots of rocks!).

Have fun.

Answer 2

We don't do product recommendations here. Generally speaking, a road bike will be faster than a MTB for the same rider.

That said, road bikes are less robust. I've popped road tyres on potholes that a rigid MTB would barely notice.

Tyre width won't change the frontal area of the bike by much if anything. Instead, the wider tyre allows use of a lower pressure which increases the rolling resistance (deformation of tyre on road surface)

Anecdotally, when I went from two old folding 23mm to wire bead 25mm slicks, my average speed improved.

Decent quality wheels (both rims and spokes) will help the most, as will having extra hand padding either in gloves or in two layers of bartape/good grips. Think of the pros on the cobblestone segments of the TDF - they use wider tyres, padding, and very few other changes.

For a commuter you will also need mudguards / fenders, and decent lights/reflectors. I'd also go with a vest and helmet. If you want to go geeky, one/two cameras and run some tracking software on a fancyphone.

Your good city roads and paths don't matter - any bike will be fine. The poor roads and cobbles - are they a significant portion of the route? Can you go alternate routes which may be better quality albeit longer?

Answer 3

The roadie will probably be faster. The mountain bike will not even be a mountain bike.

At your price range:

1. Tyre rolling resistance, both bikes will probably have crappy tyres, it is likely, but not certain, that the road bike will have less rolling resistance.
2. Weight of the bike, the MTB will be at least 3 kilos heavier, this is a plus on descents, irrelevant on flats, bad on ascents. Rotating weight will hinder acceleration.
3. Aerodynamics, the faster you go the more important this is, that road bike appears to be reasonably aerodynamic and will put you in a more aerodynamic position than most mountain bikes.
4. Wheel size, the 26inch wheels roll worse on everything, even if you get the mountain bike, try to avoid 26inch wheels for your purposes.

Damaging the wheels from cobbles and cracked pavement is not very likely, however it is not so uncommon for new wheels to need to be trued again after bedding in over 300km or so. I know several people who ride 28mm in Moscow on cheap road bikes, lots of nasty roads there, only ever heard complaints about sore buttocks, not broken wheels.

Please note that "higher pressure = less rolling resistance" is a simplistic generalisation which, despite having general truth to it, is ultimately false for road bikes and a very flawed way of thinking for mountain bikes on actual mountain bike terrain.

Depending on their construction the 32mm tryres might be FASTER than your 25mm, or if you have hard rubber with puncture resistant layers etc then both the 32 and 25mm could conceivably roll worse than tubeless 2.25inch Racing Ralph evo MTB tyres being run at 35psi, let alone an expensive MTB semi slick run at a high pressure: http://www.bicyclerollingresistance.com/mtb-reviews/continental-speed-king-ii-racesport-2015

Take a look at the comparison of these 32 to 47mm tyres to see something rather unexpected also: http://www.bicyclerollingresistance.com/specials/schwalbe-marathon-32-37-40-47

The take away lesson should be that most people cannot tell much about rolling resistance without actually measuring it, in an appropriate setting, furthermore, most simplistic assumptions about rolling resistance are likely to be invalid in the real world (elements of these measured tests included) as has been repeatedly shown in recent years.

P.S. I would never recommend an urban bike to anyone ever, I would also never recommend a mountain bike under around 700euros (buy second hand if you can't afford 700euros!) as it simply will not be an actual mountain bike, even 700euros is really border line for an actual mountain bike, but there are some appearing at that price range, you just have to wade through all the trash to find them.