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Do I need a road bike to go fast, my average mph is normally around 11 - 12mph according to strava & fitbit

The thing is I normally overtake most people, and some cars when I'm going downhill, except the roadies who seem to blast past.

I'm riding a Boardman CX converted to flat bar for the better MTB disk brakes.

I ride about 15 miles per day on my commute to work and back.

Do I just need to loose some weight or add some strength to my legs ?

I ask the question because I see the threads where people are saying they ride 20mph + as average.

  • 1
    The terrain for averaging 20mph+ is a huge factor (wind and incline). On flat land or downhill , it makes sense. But uphill or with a significant opposing wind? Probably not. – Batman Jun 19 '17 at 0:41
  • Riding fast is all about saving energy where you can and putting it down as forward power. So not just pushing harder with the legs - you need "more" of it to go to propulsion and decrease losses. Whether that's losses to rolling resistance of tyre tread, aero losses, or technique doesn't matter. Carrying less weight certainly helps, whether its the bike weight, your gear weight, or your internal weight. – Criggie Jun 19 '17 at 2:42
  • I'm somewhat reminded of this Porsche 911 vs VW Beetle race. ;) – Batman Jun 20 '17 at 1:43
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The short answer is that:

  1. Yes a well sorted road bike can increase your speed, if it is done right;
  2. That said, you can optimize a CX bike to be very similar in speed to a dedicated road bike; and
  3. You need to get a number of pieces right (regardless of the bike category) to make higher speeds easier.

While a human on a bicycle is an incredibly efficient transportation machine we don't have much power to work with, so speed gains must be made through a focus on efficiency. You can of course always become a stronger rider, but even the strongest riders are limited by a slow setup.

For context I commute 15 miles (24 km) each way to work (48 km total) with a weekly average speed of about 20 miles per hour (32 kph). This is over mostly flat terrain (only 110 m climbing). I usually try and maintain about 21-26 mph (35-42 kph) on the flats to hit that average seed. This is on a "performance endurance" road bike.

In previous years with a more standard commuter setup and I was on average about 4-10 kph slower depending on the setup (slowest was on wide commuter tires with fenders and a very upright position). This was for a similar level of fitness and power input (measured with a power meter).

That is a gain of 14-40% from paying attention to all the little details and I must say I am enjoying my commute much more!

In terms of average speeds, it really can be a death by a thousand cuts. For a commuting setup I have listed the pieces I believe gave the biggest speed gains. No single one will be overly noticeable on its own, but add together it can translate into some considerable gains.

Setup details I believe that had a large impact include:

  1. Panniers - like pulling sails through the wind. I now use a small roll bag mounted to the front bars (backpack would be faster, but I don't like carrying things on my back).
  2. Body position - Upright body postures may be more comfortable* but it increases your frontal area (i.e., how much wind you push). I have been fixing flexibility issues and have dropped my cockpit a couple inches down and extended it by an inch. This lets you present less of your chest to the wind (i.e., smaller frontal area). Width of your handle bar also impacts your frontal area. I keep the width the same as my shoulders which actually feels best on a low slung cockpit.
  3. Tires - Puncture proof tires roll slow. I am running performance tires set up tubeless so that I can still get some puncture resistance while going fast. This provided a really noticeable reduction in rolling resistance.
  4. Wheels - regular box section wheels add noticeable drag at higher speeds, I went to some moderately aero wheels this year (and matched the correct tire width to the rim for least aero drag).
  5. Clothing - anything even slightly baggy is like dragging along little speed sucking parachutes. I once again wear tighter road clothing as I used to many years ago.

* Note: I understand that lower body positions are usually perceived to be uncomfortable, but find lower body positions fine under higher efforts and at times find higher positions uncomfortable for for harder efforts as you keep bending your upper back to get out of the wind, rather than stretching it out on a lower and longer cockpit. Optimal position really depends on the type of riding you do.

If you notice all of the optimizations I mentioned may be equally applied to a road or CX bike. So I would start there rather than necessarily a new bike (n+1 rule be damned). What type of bike is only a detail in the quest for speed!

There are also other basics (such as saddle height) that I have assumed you have already figured out (i.e., see mattnz's answer).

Finally, while not directly attributed to the bike setup other factors that can affect the ability of your body to do work:

  1. Sleep, eating, physiology (e.g., hydration) and endocrinology (e.g., hormone imbalances).

You need to have all these in order as well to maintain high average speeds.

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  • a rather good reply to be fair :) – garyconstable Jun 19 '17 at 20:52
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People say a lot of things... Be careful comparing yourself to guys that ride a couple of hundred miles a week (and have done for decades), it takes years and many long hours of riding to get that cycle fit. Also pelotons will travel a lot faster than solo riders, so when people boast about averages and PB's and Strava times, find out if it was solo or not. Plenty of riders can maintain 20MPH solo, but as you have noticed, plenty more cannot. If you are looking for motivation to push yourself a bit harder, when one of these fast guys passes you, drop in behind and see if you can keep up, even if for a short time, if you don't want to be rude, ask if you can tag along.

A road bike will allow you to ride faster, but it won't turn you into superman. After a very quick look at the Boardman CX, I doubt a road bike will make a big difference. A few things you could do to help speed you up.

  • Bike fit - is the bike set up with the seat height and position correct. Are you producing and getting power to the wheels as efficiently as possible.

  • Exercises - look up some exercises aimed at improving pedal stroke and cycling fitness. You need to become more efficient and/or stronger to go faster.

  • Tires- As its a CX bike, the tires it came with will be less than ideal for pure speed on roads. Changing to a smooth road tire and inflating them properly will make the biggest difference.

  • Go back to drop bars, or look at aerobars so you can get into a lower and more aerodynamic position.

  • Wheels / hubs - The wheels it came with are not the lightest. This makes a bigger difference when accelerating, but for steady riding an upgrade that makes a noticeable difference is not cheap. If you are looking towards this kind of upgrade, changing to a road bike might be worth considering.

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2

Flat bars are costing you some speed and so will your CX tyres (to a lesser extent). Converting your bars back to drops would make you faster for the same effort. So would mounting slick road tyres.

To convince yourself of the importance of position on your bike try cycling at a steady level of effort while holding your bar ends as normal. Now while maintaining the same effort, move both your hands towards the stem so they almost touch in the middle. I almost guarantee that your speed will go up by 1 or 2kph because it forces you to lower your upper body and also narrows your front profile.

Head to the Bike Calculator and experiment with expected speed when changing riding position to get a feel for how much "free" speed you are leaving on the table because of your flat bars.

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  • 1
    Remember converting between drops and flat bars is one of the more expensive changes on a bike. Would not recommend doing - keep it as-is and buy a bike like you want. – Criggie Jun 19 '17 at 11:12
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    @Criggie the OP has already gone the other way so might still have parts. (this should probably be mentioned in the answer though) – Chris H Jun 19 '17 at 11:32
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    Hence the converting back to drop! – zeFrenchy Jun 19 '17 at 12:11
  • Yes I still have the drop bars - took them off because the Tektro Lyra brakes are a death trap waiting to happen - I have slick tyres, schwalbe marathon plus. I also have mud guard and a rack fitted. – garyconstable Jun 19 '17 at 12:37

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