How much faster are fast bikes?

ZMC888

Given the same power, let's say 200 watts and no wind on a smooth flat road with a normal moderately aero rider how much speed do you lose for each different bike, approximately using a typical tire for that bike? I think I can do a few and could others with more knowledge give us thoughts on how much at the faster end of the spectrum? Or maybe I'm totally off, set me straight as to why?

Full Suspension 150mm travel mountain bike with knobbly 2.5inch tires. 24-26km/h
Cross Country mountain bike running fairly quick tires 2.0-2.1 inch 27-28km/h
CX Bike with CX tires 29-30km/h
CX Bike with Slick tires 30-31km/h
Endro/gravel bike with slick tires 31-32km/h
All-round road race bike ??
Aero road bike ??
TT bike ??

Anonymous

I think the user called Rower63 has written a simple algorithm to work this out on his website, based on a lap of Richmond Park (in SW London).

There are a lot of variables.

Also - you can't fix the power and then define the speed.
'Moderately' aero is also highly subjective and really down to the geo of the bike.

imposter2.0

http://www.analyticcycling.com/

ZMC888

Imposter wrote:

http://www.analyticcycling.com/

Thanks!

thomasmorris

ZMC888 wrote:

Full Suspension 150mm travel mountain bike with knobbly 2.5inch tires. 24-26km/h
Cross Country mountain bike running fairly quick tires 2.0-2.1 inch 27-28km/h
CX Bike with CX tires 29-30km/h
CX Bike with Slick tires 30-31km/h
Endro/gravel bike with slick tires 31-32km/h not sure you'd measure a difference from a CX with slicks
All-round road race bike ??
Aero road bike ??
TT bike ??

From CX with slicks through to Aero road bike you'd not measure much difference if any at around 200 w / 28-32 kmh. Most of these bikes the geometry is similar enough that most people could achieve the same body position on each.

At 300 - 400 watts and 40 kmh + you might start to see small differences in speed between those bikes, but I'd still expect it to be less than 1 km/h between each class.

Speed gains by going to TT bike are quite personal as it comes down to flexibility and morphology to get the aero benefit. At 200 watts my TT bike is roughly 2 km faster than my all round race bike. At 300 watts thought it's more like 4 km faster.

Speed gains from MTB to road bike are more ubiquitous as quite a bit comes from rolling resistance which isn't personal.

ZMC888

thomasmorris wrote:

ZMC888 wrote:

Full Suspension 150mm travel mountain bike with knobbly 2.5inch tires. 24-26km/h
Cross Country mountain bike running fairly quick tires 2.0-2.1 inch 27-28km/h
CX Bike with CX tires 29-30km/h
CX Bike with Slick tires 30-31km/h
Endro/gravel bike with slick tires 31-32km/h not sure you'd measure a difference from a CX with slicks
All-round road race bike ??
Aero road bike ??
TT bike ??

From CX with slicks through to Aero road bike you'd not measure much difference if any at around 200 w / 28-32 kmh. Most of these bikes the geometry is similar enough that most people could achieve the same body position on each.

At 300 - 400 watts and 40 kmh + you might start to see small differences in speed between those bikes, but I'd still expect it to be less than 1 km/h between each class.

Speed gains by going to TT bike are quite personal as it comes down to flexibility and morphology to get the aero benefit. At 200 watts my TT bike is roughly 2 km faster than my all round race bike. At 300 watts thought it's more like 4 km faster.

Speed gains from MTB to road bike are more ubiquitous as quite a bit comes from rolling resistance which isn't personal.

So basically you think that a CX bike with slicks could pretty much hold its own with an all round road bike or endurance bike on slicks unless you are really pushing it? Interesting...so the main differences between bikes outside of a flat road scenario come down to weight on climbs.

So then, if you were not a racer, and the marginal gains at higher speeds were not really an issue, a carbon fibre CX bike with hydraulic brakes could be an ideal bike..if you had a few different wheel-sets shod differently for different purposes?

Anonymous

Basically, yes.

There are some geometry differences (higher BB on a CX bike) but many people are going down the CX or disc brake route so you can fit massive tyres for going off road and have a pair of nice wheels for the sunday club ride.

ZMC888

coriordan wrote:

Basically, yes.

There are some geometry differences (higher BB on a CX bike) but many people are going down the CX or disc brake route so you can fit massive tyres for going off road and have a pair of nice wheels for the sunday club ride.

Making me think....

So maybe if I had a carbon fibre CX bike with a threaded BB, compact 50/34 gearing and then maybe an 11-32 cassette and a bunch of different wheelsets all shod differently I could potentially do a sportif one day and be competitive, do an Everesting another day, go gravel grinding one day and then go bike-packing all on the same machine, and it could do each thing pretty damn well, within say 1-3% of a dedicated bike?

Anonymous

100% yes, and an excellent idea. The good thing being that you wouldn't necessary need the 11-32 cassette on every wheelset - just the off road one. You could have a 11-25 on some deep section wheels for flat, fast rides and an 11-28 on some lightweight climbing wheels.

Now - which bike gives you the best of all worlds? I don't know. I would start a thread with a better title as this one is probably going to put people off reading it, sorry!

EDIT - maybe not 1-3% - it will have its strengths and weaknesses in each area - some more than others, but you can probably chose a bike based more closely on what you care about more.

ZMC888

coriordan wrote:

100% yes, and an excellent idea. The good thing being that you wouldn't necessary need the 11-32 cassette on every wheelset - just the off road one. You could have a 11-25 on some deep section wheels for flat, fast rides and an 11-28 on some lightweight climbing wheels.

Now - which bike gives you the best of all worlds? I don't know. I would start a thread with a better title as this one is probably going to put people off reading it, sorry!

EDIT - maybe not 1-3% - it will have its strengths and weaknesses in each area - some more than others, but you can probably chose a bike based more closely on what you care about more.

Doesn't need to be CX does it? Any 'disk' road or CX bike would do it unless the front end is totally slammed?

Anonymous

Things to consider:
Geometry - Road bikes may be skittish off road. Off road bikes may have higher front ends and higher BBs and feel a bit sluggish on the road. Note this is a maybe!
Tyre Clearance - road bikes may not necessary fit the large tyres for gravel riding (depending how large you want to go)
Your preference - do you want equal all rounder or are you happy to compromise on one area to get better performance elsewhere.

Look at gravel/adventure bikes as these may fit the bill.

meanredspider

Yup - personally I wouldn't do a CX bike but a gravel/adventure bike - partly because of geo and partly because many CX bikes come with CX groupsets which are a bit narrow up front for road use. Adventure bikes tend to come with more bits and bobs like guard and pannier mounts and things like a 3rd water bottle mount (useful for more than bottles) etc

ZMC888

coriordan wrote:

Things to consider:
Geometry - Road bikes may be skittish off road. Off road bikes may have higher front ends and higher BBs and feel a bit sluggish on the road. Note this is a maybe!
Tyre Clearance - road bikes may not necessary fit the large tyres for gravel riding (depending how large you want to go)
Your preference - do you want equal all rounder or are you happy to compromise on one area to get better performance elsewhere.

Look at gravel/adventure bikes as these may fit the bill.

I want to go as fast as possible and climb quickly, and keep the weight down. BUT I'm not a racer and I'm 42. I'm in pretty good shape though. In my area we sometimes do night-time flat land sportifs at night in the summer, I've got plenty of mountain bikes for doing gnarly off-road specific duties.

So I'd say 90% road and climbing and 10% gravel & hard-pack, but half of those roads will be pretty darn rough. I think I'd be happy with 32mm max tire clearance.

ZMC888

meanredspider wrote:

Yup - personally I wouldn't do a CX bike but a gravel/adventure bike - partly because of geo and partly because many CX bikes come with CX groupsets which are a bit narrow up front for road use. Adventure bikes tend to come with more bits and bobs like guard and pannier mounts and things like a 3rd water bottle mount (useful for more than bottles) etc

Yeah, not fussed with 'adventure' bikes. I do bikepacking with a 30 litre backpack, 13 litre saddle bag and a bag on the bars. I don't need or want any touring attachments or the weight that comes with them. I think going too touring and gravel is a mistake, not because I dislike the bikes in any way, more because I'll be 90% plus on road and climbing, this needs to be a priority. Not sure I want any extra weight or any on-road handling sluggishness.

Maybe just get a fairly neutral (not slammed) all-round road bike and then rely on the tires and my bike handling skills for doing gravel and dirt?

meanredspider

Yup - in that case you want a road bike with great tyre clearance. A colleague said today that there were now Ravel bikes - road bikes with big tyre capability. My Volagi pretty much fits that bill.

Anonymous

'How much nicer are nice bikes' would be a better question.

The only way to answer the original question is to buy a fast bike and see what you think.

My fast bikes are much nicer than my slower ones, and I am not too bothered about how much faster they are.

If I want to go fast it makes sense to ride the fast one though.

ugo.santalucia

ZMC888 wrote:

coriordan wrote:

Basically, yes.

There are some geometry differences (higher BB on a CX bike) but many people are going down the CX or disc brake route so you can fit massive tyres for going off road and have a pair of nice wheels for the sunday club ride.

Making me think....

So maybe if I had a carbon fibre CX bike with a threaded BB, compact 50/34 gearing and then maybe an 11-32 cassette and a bunch of different wheelsets all shod differently I could potentially do a sportif one day and be competitive, do an Everesting another day, go gravel grinding one day and then go bike-packing all on the same machine, and it could do each thing pretty damn well, within say 1-3% of a dedicated bike?

Indeed, join the club... I only swap the tyres and the cassette

thomasmorris

ZMC888 wrote:

thomasmorris wrote:

From CX with slicks through to Aero road bike you'd not measure much difference if any at around 200 w / 28-32 kmh. Most of these bikes the geometry is similar enough that most people could achieve the same body position on each.

At 300 - 400 watts and 40 kmh + you might start to see small differences in speed between those bikes, but I'd still expect it to be less than 1 km/h between each class.

So basically you think that a CX bike with slicks could pretty much hold its own with an all round road bike or endurance bike on slicks unless you are really pushing it? Interesting...so the main differences between bikes outside of a flat road scenario come down to weight on climbs.

So then, if you were not a racer, and the marginal gains at higher speeds were not really an issue, a carbon fibre CX bike with hydraulic brakes could be an ideal bike..if you had a few different wheel-sets shod differently for different purposes?

It would be best compromise speed wise, but why compromise at all? There is no ideal bike however, because that means having only one. Ideal is having more bikes

But essentially yes. If I wasn't racing, I wouldn't buy a race bike.

super_davo

I set all my bikes up the same, same bars, saddle height and setback, bar height etc.
Once you strip your position out of the equation my average speeds stay very similar whichever bike I'm on. I've come to the conclusion there is next to no difference in speed between my Battaglin carbon race bike and my Ribble winter bike over regular terrain. Aero is the biggest limiter, and your position makes far more of a difference than the bike. Even on my £100 eBay Langster fixie from 2006, I can keep a decent average on flattish ground.
Why have a flash bike then? The comfort is definitely better on the Battaglin, as are the crispness of the shifts, brakes, handling. It's lighter which helps when it's hilly (probably more psychologically). But most importantly it looks great.
If you buy a flash bike expecting to gain 2-3mph, you will be disappointed. You get way more free speed from wearing closer fitting clothes.

Anonymous

My average speed on a fat bike is not far off 3mph difference from a light aero road bike, on the same 30 mile loop, with a similar effort (i.e. trying hard to get a good AVS).

Its a decent percentage though, and I still much prefer to ride the 'fast' road bike, to a slightly less 'fast' road bike.

Where do you buy these 'race' bikes from then?
I thought race bikes were road bikes that you choose to race on?

Anonymous

ZMC888 wrote:

coriordan wrote:

So I'd say 90% road and climbing and 10% gravel & hard-pack, but half of those roads will be pretty darn rough. I think I'd be happy with 32mm max tire clearance.

I would vote 25mm and just go pretty darn slow on the pretty darn rough personally.

Riding 32mm tyres for 90% tarmac seems odd to me.

Why even bother to ask about speed if you are looking to ride 32mm tyres?
Just ride 32mm tyres and get what you get.

Just seems like nice bike/fast bike bashing to me :roll:

meanredspider

Significant difference between my Foil on Rubino Pros and the Jamis Renegade on S-Ones - probably 2kmh on exactly the same flat loop done multiple times. The tubeless S-Ones have pimples on the surface and are 30c versus 25c.

Absolutely no measurable difference between the Foil and the Volagi when running the same tyres.

cycleclinic

Get a rigid 29er. Use good low rolling resistance tyre and go tubeless. Bike weight will be 10kg or less. Add some drop bars if you like. Jtek do shotmate to allow shkmano rs685 shifter to work with an xt 11 speed mech. For the chainset use a race face for similar dorect mount chainset, you can then fit a 42t or 44t chain ring and 11 to 40t rear cassette.

My 29er is not quite to that spec yet but that is where i would like it to be. More capable that a gravel bike but quite quick on the road.

Position is important but some bikes lend themselves to more aero position than others. Even small difference in position can make a big difference the drag yoj experience. The bike however does make a difference. It is on the order of wheels, i am not saying the same but the same sort of scale.

A good race bike will allow you to take a very aero position. It is just not possible to set my genesis equilibrium the same way.

I have a old trek 1992 2300 and a look 795 both have a 590mm effective top tube, both bikes have the same saddle height. Both bikes have the same saddle to handle bar drop (i think on the trek might be 5mm bigger), both bikes have the same length stem. Superfically they should allow me to take the same position but they dont. This is what i mean by a good race bike allows you to adopt a more aero position.

Position, clothing, wheel and bike are the order of things for aero effects.

A 29er can be made quite aero by using a uncorrected rigid fork (i.e a short one) to drop the front end, use a long stem, flared drop bars and you get a bike which can be ridden over rougher ground more comfortab'y and quicker. I suppose a good gravel bike might look quite similar but would lack the mud clearance. Monster cross bikes is what i am trying to describe.

ZMC888

Carbonator wrote:

ZMC888 wrote:

coriordan wrote:

So I'd say 90% road and climbing and 10% gravel & hard-pack, but half of those roads will be pretty darn rough. I think I'd be happy with 32mm max tire clearance.

I would vote 25mm and just go pretty darn slow on the pretty darn rough personally.

Riding 32mm tyres for 90% tarmac seems odd to me.

Why even bother to ask about speed if you are looking to ride 32mm tyres?
Just ride 32mm tyres and get what you get.

Just seems like nice bike/fast bike bashing to me :roll:

I've got one alloy Enduro bike in the UK with 25mm tires (Specialized Secteur) and an other steel frame CX here in China with 28mm tires. I think for me 28mm is about perfect, I love the handling in the corners and the cushioning on rougher roads, but an extra wheelset with almost slick 32mm tires and slightly knobbly edges for bike-packing and gravel riding duties might be an idea. Also another set with maybe thinner faster 25mm tires for the billard smooth roads around town that we sometimes do group rides on.

Absolutely no bashing going on, just dreaming of a new bike and thinking of options....

ZMC888

thecycleclinic wrote:

Get a rigid 29er. Use good low rolling resistance tyre and go tubeless. Bike weight will be 10kg or less. Add some drop bars if you like. Jtek do shotmate to allow shkmano rs685 shifter to work with an xt 11 speed mech. For the chainset use a race face for similar dorect mount chainset, you can then fit a 42t or 44t chain ring and 11 to 40t rear cassette.

My 29er is not quite to that spec yet but that is where i would like it to be. More capable that a gravel bike but quite quick on the road.

Position is important but some bikes lend themselves to more aero position than others. Even small difference in position can make a big difference the drag yoj experience. The bike however does make a difference. It is on the order of wheels, i am not saying the same but the same sort of scale.

A good race bike will allow you to take a very aero position. It is just not possible to set my genesis equilibrium the same way.

I have a old trek 1992 2300 and a look 795 both have a 590mm effective top tube, both bikes have the same saddle height. Both bikes have the same saddle to handle bar drop (i think on the trek might be 5mm bigger), both bikes have the same length stem. Superfically they should allow me to take the same position but they dont. This is what i mean by a good race bike allows you to adopt a more aero position.

Position, clothing, wheel and bike are the order of things for aero effects.

A 29er can be made quite aero by using a uncorrected rigid fork (i.e a short one) to drop the front end, use a long stem, flared drop bars and you get a bike which can be ridden over rougher ground more comfortab'y and quicker. I suppose a good gravel bike might look quite similar but would lack the mud clearance. Monster cross bikes is what i am trying to describe.

For me I don't want to make compromises on road riding. I might be wrong, but I think a rigid 29er isn't going to be fast enough on acceleration or on hills. I'm teetering on bikes like maybe Trek Emonda, Trek Domane, Giant TCR or Giant defy. I want a road bike that leaves almost nothing on the table on the road, but switch out the wheelset and it becomes more capable for other duties. Agree with tubeless. Might even get one set of tubular 25mm for fast riding around town, and tubeless (if I can find the right tires) 28mm clinchers for general riding and climbing and then a set of 32mm tubeless CX for gravel griding/bikepacking.

fat daddy

other than the MTBs, I use a 12kg Flat bar hybrid on 32c tires and a 7kg road bike with 25c tires.

There is very little if any difference in speed, infact the majority of my strava segments the PRs are on the hybrid. The 32c tires don't slow the bike down, but they do allow me to ride over the potholes and badly laid road repairs a lot faster than I can comfortably do on the road bike.

Aero makes FAR more difference in my case .... and this is where the road bike excels ..... I can easily get into the same position on both bikes, but I can stay there a LOT longer on the road bike, it is naturally a more aerodynamic position which means my longer rides are quicker on the roady, but the short hard segments are quicker on the hybrid

stueys

I use a Caadx as my winter bike, it spends 90% of its time sitting on a set of wheelsmith aero disc wheels shod in 28cc conti 4s and wearing guards. That's probably 65% of my total riding including all of the club run type stuff. Five minutes of taking guards off and putting cx wheels on (separate set of wheels which stay shod in cx tyres) and it's ready for cx racing and for trail duties. They make really versatile bikes, its the closest thing to a do everything bike. Position wise I run it a smudge higher than my nice road bike but that's a choice, I could set it up the same if I needed.

I run the nice road bike more as a full on bike (deep section wheels, aero road bar, di2 ,etc, etc) it's faster than the caadx but that's down to (a) the slightly more stretched position I run and (b) the cx bikes is set for comfort and not speed (non aero guards, heavier tyres, etc). All of those things are discretionary and then I honestly don't think there would be any real performance difference between that and my quite expensive nice bike.

haydenm

Just to offer some more opinion, my Genesis Equilibrium and the Supersix cost me roughly the same, have the same groupset and similar level spec. The Genesis weights ~10.5kg and the Supersix is nearly 2kg lighter. I can't say exactly why but the Supersix feels much faster. I'm sure a lot of that is due to the way the SS feels so responsive and nippy but on climbs (and that is the majority of riding where I live) it is significantly faster, in one highly unscientific strava test on my commute I am 51 seconds faster up a 2km climb with a max grad. of 14%. On the flat I think I could hold a significantly higher average speed, mostly down to aero position but we shall see.

Having said that, I've done consecutive 200km days on the Genesis, I'm sure I could do the same on the Supersix but I'm not in any great hurry to try...

thomasmorris

ZMC888 wrote:

For me I don't want to make compromises on road riding. I might be wrong, but I think a rigid 29er isn't going to be fast enough on acceleration or on hills. I'm teetering on bikes like maybe Trek Emonda, Trek Domane, Giant TCR or Giant defy. I want a road bike that leaves almost nothing on the table on the road, but switch out the wheelset and it becomes more capable for other duties. Agree with tubeless. Might even get one set of tubular 25mm for fast riding around town, and tubeless (if I can find the right tires) 28mm clinchers for general riding and climbing and then a set of 32mm tubeless CX for gravel griding/bikepacking.

If you can get saddle set back, saddle height, bar drop, bar width and bar reach the same across two bikes, then you're in the same position. In which case, with 25 mm slick tyres, at 200 W you won't be sacrificing any speed, regardless of whether the bike is marketed as a MTB, a CX a gravel bike, an endurance bike, a race bike or an aero bike...that's what my post earlier was saying.

If I was buying one bike to do it all, i wouldn't be worried that it would be slow on the flat at 200w once it had slick tyres on. But I would be worry that:
1) The gearing range would be adequate for flat road and 'tough' trails. This could be mitigated to some extent by changing different cassettes on different wheels with different tyres. Depends how tough your off road is though, I do three times the speed on a fast club run than what I do on tough trails on the mtb... simply swapping cassettes wouldn't make up for that type of difference.

2) Would setting it up so I have fast road position mean I compromise the handling off road? Could be mitigated by swapping spacers to give less drop or swapping to a shorter stem... would be faff before short rides, and obviously rides which are a mixture of terrain you'll be compromised on one surface or the other. Would I want to change to wider bars?! That really is a super faff!

3) Would the slack angles of the more off road bikes dampen the handling in a pack on the club run? Or the tighter angles of the more road orientated bikes make it a bit skittish off road? I think I could live with either, but it would be a much more noticeable compromise than speed.

4) Clearance, more is better... however, more clearance means longer stays and forks, which can mean less compact bike (See above for handling compromises).

5) Toe clearance... my road bikes all have overlap due to their short wheelbase. It makes the handling feel great and I'm never weaving across the road at 3 mph so it's never really an issue... but on a 25% technical trail I probably would be weaving and toe overlap would certainly be an issue!

You'll always have to make some compromises on the above. None are about all out speed, and some are dependent on the type of riding your planning. But all are reasons why people may just buy two bikes.

darkhairedlord

The only thing you will do beyond a road bike at 200W or less is look silly.
Really, no difference in speed, just aesthetic; there is nothing good about the aesthetic of fast when being over taken by an old lady on a Raleigh Shopper.

cougie

My Ali cx bike with Road tyres seems as fast as my carbon aero Road bike.

It's really not about the bike.