What makes a fast m...
 

[Closed] What makes a fast mountain bike?

Posts: 762
Free Member
Topic starter
 

I know speed isn't everything, and some mountain bikes can be ridden on terrain where others will be being pushed or carried, but what sort of bike lets you cover lots of ground in a day?

Is low weight (for climbing), skinny tyres and narrow bars (for aerodynamics) where it's at? Mountain bikers don't seem too bothered about this kind of thing, but there must be some sort of bike which is easier to keep rolling at speed, with less effort/energy expenditure.


 
Posted : 09/12/2016 11:56 am
Posts: 251
Full Member
 

It's not about the bike is the short answer.


 
Posted : 09/12/2016 11:57 am
Posts: 13291
Free Member
 

The person stealing it


 
Posted : 09/12/2016 11:58 am
Posts: 13192
Free Member
 

Given the same rider then it is likely a carbon hardtail with skinny tyres on and a big ring up front would be the fastest in my opin. I don't think the width of the bars would make any difference, well maybe a little but minimal.


 
Posted : 09/12/2016 12:00 pm
Posts: 6273
Full Member
 

I don't know the answer, but I do think that the importance of weight in a mountain bike is over-exaggerated. Probably just because it is easy to measure and simple to market. But a bike that is more efficient (e.g. stiffer, lower rolling resistance etc) will usually beat something that is just lighter. Weight matters when you are lifting the bike (over a fence, onto the car, or just onto your shoulders), but other than that I think it should be lower down the list than it seems to be.


 
Posted : 09/12/2016 12:03 pm
Posts: 0
Free Member
 

Legs->Tyres->Weight->Aero

A proper fast XC tyre makes a world of difference - especially to lighter or less fit riders that really don't have an extra 50w to spare on rolling resistance.


 
Posted : 09/12/2016 12:04 pm
Posts: 28712
Full Member
 

Mine for example was a Giant XTC29, really good at covering ground well with something like the old Racing Ralphs installed. I still struggle to get near my PBs on many of the faster Ridgeway type trails.


 
Posted : 09/12/2016 12:04 pm
Posts: 0
Free Member
 

the rider


 
Posted : 09/12/2016 12:07 pm
Posts: 587
Free Member
 

Are you talking about canal tow paths, riding around a muddy field here... ie glorified road cycling.

If you mean proper MTBiking then Surely rider input verses a tool for the right type of terrain.


 
Posted : 09/12/2016 12:08 pm
Posts: 17313
Free Member
 

an electric motor and a battery?


 
Posted : 09/12/2016 12:09 pm
Posts: 1789
Free Member
 

KTM Aera comp 29er is electric quick. Carbon fibre, stiff rear end, 29inch wheels and tripple chain ring all add up to a very quick xc mountain bike. I think a lot is about gear ratio and crank arm length.


 
Posted : 09/12/2016 12:10 pm
Posts: 7119
Full Member
 

29" wheels seem to be quite a bit faster for covering ground than 26".


 
Posted : 09/12/2016 12:10 pm
Posts: 3450
Full Member
 

Rider
Rider weight
Riders weight to power ratio

Terrain
Conditions
Distance
Then the bike ....

Weight is a falsity in some cases,


 
Posted : 09/12/2016 12:11 pm
Posts: 8927
Free Member
 

A pub with a big log fire and loweswater gold on?


 
Posted : 09/12/2016 12:11 pm
Posts: 1991
Free Member
 

Fastest in what respect Up? Down ? XC ?

Down a full bounce with loads of travel good wheel set up and brave rider big conkers

Up , Lightweight plus bike with good gearing and big lungs

Xc , carbon 29er no weight big legs and lungs and a full English


 
Posted : 09/12/2016 12:13 pm
Posts: 0
Free Member
 

Terrain
Conditions
Distance
Then the bike ....

Weight is a falsity in some cases,

I get the feeling you've never actually ridden a fast MTB.
Give me an XC race bike and i'll knock out faster times over any kind of distance than a trail/enduro bike with burly tyres on regardless of the conditions.


 
Posted : 09/12/2016 12:19 pm
Posts: 0
Free Member
 

After legs, I'd guess at a 29er with fast tyres (but crucially still able to hook up and give a level of confidence) on something with 100mm of travel and 'average' geometry, to give a bit of cushioning and all day easiness to allow the rider to just keep pushing the pedals.
Having said that, I'm always amazed at how different a bike can [i]feel[/i] without it making a blind bit of difference to how well I cover ground or how fast I go.


 
Posted : 09/12/2016 12:19 pm
Posts: 0
Free Member
 

People under-estimate the importance of aerodynamics when riding mountain bikes IMO.

can't remember figures (wich will vary from case to case anyway) but its a fairly low speed at which overcoming aerodynamic drag uses up a lot of you power.

So narrower bars and a good body position do make a big difference. tuck in those elbows!


 
Posted : 09/12/2016 12:26 pm
Posts: 0
Free Member
 

Whatever Nino is riding


 
Posted : 09/12/2016 12:29 pm
Posts: 587
Free Member
 

Get rid of the flappy clothing, Enduroists head to toe in lycra a marketing mans dream!


 
Posted : 09/12/2016 12:31 pm
Posts: 0
Free Member
 

People under-estimate the importance of aerodynamics when riding mountain bikes IMO.

can't remember figures (wich will vary from case to case anyway) but its a fairly low speed at which overcoming aerodynamic drag uses up a lot of you power.

So narrower bars and a good body position do make a big difference. tuck in those elbows!

I think its around 18mph, so pretty quick for an MTB, hence no-one is really bothered about it


 
Posted : 09/12/2016 12:32 pm
Posts: 3450
Full Member
 

I get the feeling you've never actually ridden a fast MTB.
Give me an XC race bike and i'll knock out faster times over any kind of distance than a trail/enduro bike with burly tyres on regardless of the conditions.

Well done but terrain plays an important issue, but then it comes down to rider ability....surely.


 
Posted : 09/12/2016 12:37 pm
Posts: 0
Free Member
 

I think its around 18mph, so pretty quick for an MTB, hence no-one is really bothered about it

See I thought it was 18kmh, which even for a below average sport cat rider such as myself is about average speed when racing on flatter courses


 
Posted : 09/12/2016 12:43 pm
Posts: 762
Free Member
Topic starter
 

I'm more of a road cyclist (audax in recent years, but on various bikes including fixies and recumbents). As you say it's difficult to pinpoint what works, but I try to pay attention to rolling resistance, drivetrain friction, aerodynamics, and frame stiffness (up to a point). I'm not too bothered about weight within reason, but some mountain bikes do seem to weigh a ton. I don't 'race' as such, but I like to be able to go at a decent pace, and having an efficient bike is less tiring to ride, and lets you conserve energy while keeping up with other riders.

I had a mountain bike lesson, and the wide bars, flappy clothes, and sticky-oot knees go against what I'm used to. Some of the bikes seem pretty hefty as well. I don't suppose there a lot you can do about rolling resistance - you probably just have to run whatever tyre gives you grip. Also, I imagine a really light bike would be a handful on the descents.

As for terrain, I was thinking of a mixed bag - maybe a coast-to-coast over a day, or some longer distance routes in Scotland, or even the North Downs Way - which I once did on my 90's rigid bike when lightweight mountain bikes were the order of the day!


 
Posted : 09/12/2016 12:47 pm
Posts: 0
Free Member
 

See I thought it was 18kmh, which even for a below average sport cat rider such as myself is about average speed when racing on flatter courses

In a xc race env then yes, lycra all the way. But for most recreational riders (which is everyone who doesnt enter races) its not important.


 
Posted : 09/12/2016 12:48 pm
Posts: 762
Free Member
Topic starter
 

Aerodynamics do come into play at lower speeds, though. It's a combination of your speed and the wind speed, so if you're riding at 8mph into a 10mph headwind it wouldn't hurt to tuck yer elbers in!


 
Posted : 09/12/2016 12:50 pm
Posts: 10497
Free Member
 

I'd say a xc marathon type bike with 90/100 mm travel both ends, good fast tyres if we're talking purely in bike terms.

Slightly left field bur my fat bike with 4.0" jumbo Jim's rolls faster than my mates Scott Genius with 2.4" advantages. We tried it on a long steady down slope from a rolling start and no pedalling. I hit 39kph and him 34kph. We weigh the same and the bikes pretty much do, there's no way that a JJ is moar aero than an advantage


 
Posted : 09/12/2016 12:51 pm
Posts: 13479
Full Member
 

Aero is surprisingly important, GMBN did an interesting video on it.


 
Posted : 09/12/2016 12:52 pm
Posts: 0
Full Member
 

I think a lot is about gear ratio and crank arm length.

PLEASE tell me that was a joke!


 
Posted : 09/12/2016 12:57 pm
Posts: 41395
Free Member
 

What makes a fast mountain bike?

Marketing and naivete


 
Posted : 09/12/2016 12:59 pm
Posts: 0
Free Member
 

Lunge - not the most scientific test and only an 8 second difference. I`m still not bothered about aerodynamics on my MTB


 
Posted : 09/12/2016 1:05 pm
Posts: 0
Free Member
 

Aerodynamics do come into play at lower speeds, though. It's a combination of your speed and the wind speed, so if you're riding at 8mph into a 10mph headwind it wouldn't hurt to tuck yer elbers in!

Bull****!. It wont make you quicker it just means you are saving a VERY minimal amount of watts to travel the same speed as someone who isnt as aero.


 
Posted : 09/12/2016 1:09 pm
 Yak
Posts: 6939
Full Member
 

not the most scientific test and only an 8 second difference.

Well that is still a 6.5% improvement, so quite a lot.

29er disk wheel anyone?


 
Posted : 09/12/2016 1:10 pm
Posts: 0
Free Member
 

Slightly left field bur my fat bike with 4.0" jumbo Jim's rolls faster than my mates Scott Genius with 2.4" advantages.

This is hardly a surprise.
Its not easy to find rolling resistance data, but what there is available shows that Schwalbe and Conti are light years ahead in rolling speed.
In my experience i've found 'fast' maxxis offerings to be more grippy than expected, but not actually fast.


 
Posted : 09/12/2016 1:12 pm
Posts: 0
Free Member
 

Well that is still a 6.5% improvement, so quite a lot.

29er disk wheel anyone?

As i said not very scientific. I bet they could do several runs with same rider and bike and get a 3 - 4 second difference anyway. How much of those 8 seconds was down to being more aero? And how much was down to having a better run, choosing better lines, carrying more speed through corners?

Then see how much of that 8 second advantage you loose trying to turn that 29r disc on the next climb


 
Posted : 09/12/2016 1:16 pm
Posts: 0
Free Member
 

Everyone I demoed a spesh epic I was amazed that there was no hidden motor - awesome fast bike

To put into context did a demo day with about 20 people. On most bikes I was about 5-8 on climb. On the epic I was first by a country mile - same bike, same rider, same course!


 
Posted : 09/12/2016 1:21 pm
Posts: 3073
Full Member
 

I tried this out on a local loop when I got a new XC 29er full suss, my first run was four minutes faster than my best ever time on my 650b hard tail.

which proves virtually nothing in the real world 🙂


 
Posted : 09/12/2016 1:24 pm
Posts: 0
Free Member
 

Haven't read all the answers so may be a repeat but taking the rider out from the equation as obviously Gee Atherton is going to be faster than me if he was on a Brompton and I was on the best bike ever... I would probably say geometry and suspension performance. I have a 29er and I'm no faster on it than I was on my orange 5 26er. The 29er fits me better and hence I'm more comfortable and hence enjoy riding it more but Im not faster. Actually Im less fit now which may make more of a difference!


 
Posted : 09/12/2016 1:28 pm
Posts: 0
Free Member
 

OOPs sorry, just re-read the title - I though it said who not what 😳


 
Posted : 09/12/2016 1:34 pm
Posts: 13479
Full Member
 

Bull****!. It wont make you quicker it just means you are saving a VERY minimal amount of watts to travel the same speed as someone who isnt as aero.

Or you could put out the same watts and be faster. So yes, it would make you quicker. And whilst the GMBN vid is not a perfect scientific study it does add some weight to the aero argument. You may choose not to be worried about it, that's fine, but it does make a difference.

Anyway, I believe be followup question to this is "why don't DHers wear Lycra".


 
Posted : 09/12/2016 1:37 pm
Posts: 0
Free Member
 

Anyway, I believe be followup question to this is "why don't DHers wear Lycra".

That's easy UCI banned it as they wanted DH to appeal to the gnar-rad-shred skater brigade. And it worked!


 
Posted : 09/12/2016 1:39 pm
Posts: 0
Free Member
 

gnar-rad-shred skater brigade

I like that description 😆


 
Posted : 09/12/2016 1:41 pm
Posts: 0
Free Member
 

lunge - I agree with you in that at the pointy end of xc racing yes those few seconds mean the difference between winning and loosing. To the rest of us mere mortals, no-one cares.

Yes you could put out a few extra watts, but so could the other guy. The speed is so low it makes very little difference.


 
Posted : 09/12/2016 1:44 pm
Posts: 0
Free Member
 

To the rest of us mere mortals, no-one cares.

Strava disagrees with you 😆


 
Posted : 09/12/2016 1:48 pm
Posts: 0
Free Member
 

To the rest of us mere mortals, no-one cares.

Not true at all, when you're on a long day out, still 50mi from home and know you're going to be grinding into a headwind for the next 3 hours then making yourself a bit smaller makes a lot of sense.


 
Posted : 09/12/2016 1:51 pm
Posts: 6273
Full Member
 

Slightly left field bur my fat bike with 4.0" jumbo Jim's rolls faster than my mates Scott Genius with 2.4"

I can believe that. When I built up my fatbike with 4.8" Jumbo Jims I was amazed to find that I was setting PBs on fire road climbs (on a bike that weighs 35 lb). OK, I've never ridden a full on race bike, but still I was beating times set on a variety of 26" and 29" hardtails and full suss trail bikes. It made me realise that tyres are more important (and weight less important) than I'd realised.

Now it's winter and I've switched to Bud and Lou tyres, the average speeds have dropped significantly. Yes the Bud/Lou weigh more than the JJs, but I'll bet it's not (just) the weight that's making the difference.


 
Posted : 09/12/2016 2:03 pm
Posts: 12522
Full Member
 

When I built up my fatbike with 4.[s]8[/s]0" Jumbo Jims I was amazed to find that I was setting PBs on fire road climbs (on a bike that weighs 3[s]5[/s]0 lb)

Me too!

A big factor is how the bike makes you feel when you're riding and pedalling. You could have the most efficient, smooth bike in the world, but if it doesn't make you go "YEAHH!!!" when you're winding it up, you may as well just sit and twiddle. Unless you're a roadie in disguise and only mtbing for the exercise/suffering. Or you're racing.


 
Posted : 09/12/2016 2:25 pm
Posts: 12522
Full Member
 

Just taken the bold step of reading the OP

what sort of bike lets you cover lots of ground in a day?

So ignore my previous post!

If we're talking "big day out for average joe, ie SDW" A well-fitted comfy, smooth, efficient bike that means you're fresher for longer is going to be the winner. cush over ultimate lowest weight, relaxed riding position over arse up, head down racey position.

If you're Ian Leitch setting a SDWD record, you're back into xc race machine territory.


 
Posted : 09/12/2016 3:28 pm
Posts: 6920
Full Member
 

I read a study a few years ago where they compared hard tails and full-sussers over a rolling XC course - it effectively came down to what was gained by the lighter hardtail on the climbs wasn't recovered on the downhill by the full-suss.
Climbing speed often comes down to the ability to getting the power through the tyres and this is where a fatter tyre wins, plus they have lower rolling resistance than a skinny tyre, so win+win.
I'd say a carbon-framed and rimmed fatbike with 4" JJs would be a killer XC weapon - certain outclimb anything and big tyres means means you can go scary-fast on the downhills.
Aerodynamics are insignificant for XC.


 
Posted : 09/12/2016 3:42 pm
 Yak
Posts: 6939
Full Member
 

So the answer is a fatbike ridden by someone in baggy kit.
Or an xc hardtail ridden in lycra with an aero helmet.
Or an orange 5.
Or a specialized epic.

Take your pick OP ! Winners - the lot of them 😉 😀


 
Posted : 09/12/2016 3:48 pm
Posts: 10497
Free Member
 

Despite my previous post, my 29er XC Carbon FS with proper XC tyres (2.2" vittoria Mezcal g+) set up tubeless is silly fast, I've set pr's everywhere I've ridden it both up and down hill on natural stuff and round trail centres.

As fast up hill as my previous 29'er XC HT with fast tyres but significantly faster down hill and traversing, especially on rooty and rough ground. It's also more comfortable so I can ride faster for longer.


 
Posted : 09/12/2016 6:58 pm
Posts: 0
Free Member
 

It's not about the bike is the short answer.

Have you not read dirt mtb mag? All bikes are rubbish apart from wor Eva is flavour of the day.


 
Posted : 09/12/2016 7:20 pm
Posts: 1014
Free Member
 

lots of different bikes are fast. DH, Enduro, XC fs and XC ht are all fastest depending on the relevant race/ terrain.

what sort of bike lets you cover lots of ground in a day?

Climbs make more difference than descents so a XC bike will be faster than a heavier bike in nearly any situation.

I would have thought a XC fs bike would be the most efficient bike for a day out.


 
Posted : 09/12/2016 7:46 pm
Posts: 0
Free Member
 

Tyres make the biggest difference for me.

Different frames and forks make some differences but tend to offset each other in my experience. Take a lap of a fairly mixed trail centre and I'll be slightly quicker on the downs on my trail bike but I'll be quicker on the ups on my lightweight carbon 100mm forked hardtail. Over a day they would kind of even out.


 
Posted : 09/12/2016 7:52 pm
 nikk
Posts: 0
Free Member
 

The answer to this is very easy, if we read the OPs posts;

deejayen

I know speed isn't everything, and some mountain bikes can be ridden on terrain where others will be being pushed or carried, but [b]what sort of bike lets you cover lots of ground in a day?[/b]

As for [b]terrain, I was thinking of a mixed bag - maybe a coast-to-coast over a day, or some longer distance routes in Scotland, or even the North Downs Way[/b]

The answer is, look at what the fastest riders ride of things like the Tour Divide etc. Put it all in a spreadsheet and weight it by finishing time, then check the bikes build out, and average the components.

29er
2.2 or 2.4 reasonably fast tyres. Some people do ok with + or fat.
100mm or thereabouts suspension. Some will be rigid, some 120. Some light XC full sussers.
Something dialed back from full on XC bike, a little more upright

It is probably more down to experience and what you like / are comfortable on / want to ride.


 
Posted : 09/12/2016 8:07 pm
Posts: 665
Free Member
 

What type of string is the longest?


 
Posted : 09/12/2016 8:13 pm
Posts: 10497
Free Member
 

The one that's cut that way


 
Posted : 09/12/2016 8:31 pm
Posts: 0
Free Member
 

Fastest bike I've ridden in the Peak District: Yeti 575 with Rock Shox Lyriks.

Fastest MTB I've ever ridden elsewhere: Cube reaction GTC 29er

Really depends where you are riding.

Most fun however was a Cotic Soul. Still miss it.


 
Posted : 09/12/2016 9:29 pm
Posts: 0
Free Member
 

There's a little rocky downhill strava segment in my local woods that I've ridden plenty of times, mostly on my Anthem. Did it a few times on a Cotic demo day and beat by PB on the Flare and Rocket. Went out one night last week on my 26" Dialled PA HT and beat those times. So that is conclusive evidence that a 26er HT is the fastest bike. QED.


 
Posted : 09/12/2016 10:09 pm
Posts: 6581
Free Member
 

The fastest bike I've ridden was the bike I was riding when I was at my fittest. It happened to be a Spesh Camber Comp Carbon 29. I briefly held KOMs on some climbs around Rivington. I'm minutes slower now whatever bike I am on.


 
Posted : 09/12/2016 10:14 pm
Posts: 6581
Free Member
 

Things appear to have moved on though - I'm almost a minute slower than the current KOM on one of the climbs. He was probably on an e-bike though 😉 https://www.strava.com/segments/1451786


 
Posted : 09/12/2016 10:21 pm
 adsh
Posts: 0
Free Member
 

On the Ridgeway Double I averaged 11.8mph on a 1x10 FS, Pedalhead averaged 13mph on a rigid singlespeed.

It's what works for you. For most a short travel FS set up to be comfortable over long periods of time works well.

My 'fish was/is perfect, my Epic is 3lbs lighter but doesn't work because the position is too aggressive.


 
Posted : 09/12/2016 10:31 pm
Posts: 3640
Full Member
 

Bull****!. It wont make you quicker it just means you are saving a VERY minimal amount of watts to travel the same speed as someone who isnt as aero.

Minimal? Wind resistance goes up with the square of speed, so on a bike with a pretty small power source it is a massively increasing amount that is lost for every mph you go faster.

Fair enough downhill off road there are other things dictating your overall speed. But on the flat into a headwind? I can think of one XC race this year where there was a massive fire road headwind section (the techy return leg was in a cutting so no tailwind benefit on the way back).


 
Posted : 09/12/2016 10:57 pm
Posts: 3611
Free Member
 

The fastest bike is the one ridden by anybody who passes me and frankly it's an unfair advantage. When I'm doing the passing it's not about the bike.


 
Posted : 09/12/2016 11:13 pm
Posts: 1
Free Member
 

What makes a fast mountain bike?

2 pages of answers and opinions and nobody has provided the actual answer...

Red bits.

Just add a few red bits, eg bar ends, grips, pedals, saddle, hubs, etc..a bit at a time until it achieves speeds you can't control,

Everyone knows red is fastest.


 
Posted : 10/12/2016 6:01 am
Posts: 1
Free Member
 

+1 coolhandluke!


 
Posted : 10/12/2016 8:03 am
Posts: 0
Free Member
 

About 2000w of #5 and 200mg of nadrolone


 
Posted : 10/12/2016 8:16 am
Posts: 0
Free Member
 

Also fast cornering vs fast in a straight line should be considered. Fast in the air? Fast over chunk? So many variables. That said, in the greater scheme there are more straight bits.

I will say I took my 1994 26" hardtail out for its annual ride last week and was near 2mph up on my average speed compared to my FS, also Rockect Ron vs a DHR II may have had something to do with it. Going though a rock garden prompted the term "bone-shaking" to rattle around in my head. I did feel like I took a more conservative line choice in the rough but if you took the ride as a whole including boring bits I'm sure I was quicker.

It will still be getting tucked away in favour of the FS as I have more FUN on sections of trail I enjoy the most. I'll take that over average speed anyday.


 
Posted : 11/12/2016 12:23 am
Posts: 3073
Full Member
 

Just go and drop 6.5k on a cannondale scalpel


 
Posted : 11/12/2016 7:51 am
Posts: 15433
Full Member
 

It's interesting that half the answers are actually addressing what makes an MTB more 'efficient' and that there's some debate on what is actually meant by "fast"...

For those that want a bike to be quicker overall i.e. up and down over mixed surfaces and terrain it's almost sounds like a CX bike (flat or drop bars?) might actually suit better and the compromises when pointed down can be lived with.

Except I don't think that is really what a lot of riders mean by "faster" narrower tyres rolling better has been reasonably well debunked now, even roadies are going fatter now.

Most 'lesure' MTBists seem to want to be able to winch to a trail head comfortably and then enjoy some brakes off, corner carving, wheels of the ground type fun without suffering too much for their kicks... For that I would say weight is a relatively minor factor (lighter is of course nice to have) and it's geometry, tyres and suspension, in that order, which provide the ability to milk "speed" from a trail... All IMO of course.


 
Posted : 11/12/2016 10:11 am
Posts: 44675
Full Member
 

on the sort of rides the OP mentions I would say weight has a big effect 'cos you will spend a lot of time climbing and the downs will not be hugely technical. then comfort, then tyres


 
Posted : 11/12/2016 10:22 am