Fast Bike, Slow Bike. What is the difference?

[Mick F]

PS:
One of the things I like to do, is to take arguments to the extreme to show the comparisons.

The question at the OP is what's the difference between a slow bike and a fast one.
We could chat all day about frame dynamics and geometry, tyre widths and pressures, gearing and cadence, steel, aluminium, carbon fibre ad infinitum.

I'm comparing a 73deg parallel road bike with a suspended road bike. Both are set up identically, and it's the same bloke riding them.
I'm no athlete, I'm no Wiggo, but I am ME and I ride a bike for pleasure and sanity. I can tell the difference in effort required to propel one bike vs the other.

I wish I could measure the pedal pressure or the muscle effort to go along on one bike vs the other. We could then quantify the power requirements.

[willcee]

Pedalling in circles.. well , there's an interesting concept.. some years ago i acquired an early moulton, and with advice from the go to guy around here, the late Wallace McNaul, extremely well known in Moulton circles in the UK, he was the first guy in Ulster to bring in the Speed six, had raced it here with a up and coming rider Trevor Cameron, and rode it himself before selling it to a neighbour of mine when i lived at home.. now rebuilt and in a local Museum....he was a great lengths advising me as a big guy, that it wasn't an ideal machine, you won't get on with it , too heavy, that said i went on and created a replica Speed Six, and found that i was bobbing and bouncing at anything other than very soft pedal inputs..I even considered modding some sort of damper, and at this stage i was offered a price from a chum to let him have it.. this was before I had put a final colour choice on the frame, she went down the road.. afterwards i did some research and found that they were designed for small guys max weight approx 10/11 stone which was about all the rubber block at the rear stays could handle.. the designer himself was a small man, and many of the Moultons that were unearthed within the UK since the 60's esp the Sixes have gone to Japan, again small guys.. in fact the guy who set the record on that epic ride on the bath circuit was a lightweight..
the comments on fast bikes are very interesting, however many of the newbies, sunday warriors et al, have never experienced a great steel bike.. but if like me you have a few to choose from on a good day, after suffering guards and winter steeds. you aren't many yards down any tarmac before you know you're on a good'un.. as has been intimated.. a lot of this speed feeling is in the mind..
A good story from an old petrol head.. back in the day in the Alps, Hannu Mikkola was testing Fords latest BDG 2.0 MK2 WORKS Rallye Escort.. The mechanics, teck guys etc all in attendance and timing him and co driver over a known stretch of alpine pass.. times were all over the shop, couldn't nail it down, maybe weather, maybe engine down on power but didn't seem to be, so they pulled the test early evening and only guys left were mikkola and his mechanic, with tool boxes and his spare wheels, they put them in the car, and started the run.. time me, says mikkola, and when they did he had set the fastest time of the day.. go figure.. as Lance would say.. will

[Gattonero]

After a recent discussion on the Touring forum about how some bikes were faster than others, i realised that I still don't understand why.

Obviously weight is a factor and tyres, etc but what is the fundamental difference or differences that make some bikes faster than others? I understand how geometry can affect the handling, but why the speed?

One part of the faster to slower discussion mentioned Surly: Pacer, Cross Check and LHT as their example.

Answers, please.

for me:
1- position on the bike
2- suitable gear ratio for the journey
3- weight, especially on the wheels and tyres
4- lack of wind

Seriously, I have toured the Norfolk coast on an alluminium single-speed that is one of my favourite bikes, no surprise that on the first day I was clocking an average of almost 30km/h over a 70km distance same when I use it on commuting, can be as fast -if not faster- than the "commuting" bike which has gears, but a more "relaxed" position and easy gears.
Then there are the road bikes, that is a different story

[simonhill]

Sorry for the delay, but on tour at the moment.

Thanks for all the replies, but it wasn't what I wanted to hear. I thought there must be certain fundamental design features that made bikes fast or slow.

The post that got me wondering was this one. viewtopic.php?f=16&t=112314&start=15

You can see in the second page that the LHT (my bike) is a slow old dog and the Pacer "a bit nippier" with the Cross in between. The worthies who commented seem to state this as an unquestionable fact. You chaps seem to put it down to much more random features.

I s'pose I could ask the question, would a similarly set up LHT and Pacer be roughly the same speed?

................but I don't think it will be something troubling me on my death bed.

Thanks again for troubling.

[Keezx]

For what it's worth, last years summer I did a coincidental "test" with an classic lugged steel roadbike and a fairly modern aluminium racer.
Setup steel bike is SLX frame, 2x 6 speed screw pignon, downtube shifters, pedals with clips, non aero brake cables , Mavic Module E rims with Conti GP 24 mm tyres, bike was put together to be used in an Eroica ride.
Weight probably app. 10,5kg (I'm not particularly interested in bike weights, never weigh them)
Alu Gianni Motta Rapido frame with Campagnolo Chorus 9 speed stuff, KinLin XC279 rims with the same Conti GP tyres, clipless pedals.
Weight app. 8,5 kg.
Everything very well maintained, geometrie of saddle, pedals and bars identical, tyre pressure ditto.
In mid July 2016 did a 60 km ride with the alu bike and came home with average 30,1 km/h.
Next day I was planning to ride again and thought it might be interesting to do the same ride with the "classic" bike.
Kept my hartrate at app. the same level and came home with average of 30,6 km/h....
Most likely the wind was a bit more favourable on day 2....obvious the bike doesn't matter that much.
If position, clothing and effort are the same, speed is app. the same.

[Brucey]

...If position, clothing and effort are the same, speed is app. the same.

that is an interesting experiment (and the result roughly what I'd expect) but if the second bike had been fitted with mudguards, a rack and heavy-duty tyres, I'd expect you to have been about 2-3kph slower in otherwise identical conditions. Probably....

cheers

[531colin]

Sorry for the delay, but on tour at the moment.

Thanks for all the replies, but it wasn't what I wanted to hear. I thought there must be certain fundamental design features that made bikes fast or slow.

The post that got me wondering was this one. viewtopic.php?f=16&t=112314&start=15

You can see in the second page that the LHT (my bike) is a slow old dog and the Pacer "a bit nippier" with the Cross in between. The worthies who commented seem to state this as an unquestionable fact. You chaps seem to put it down to much more random features.

I s'pose I could ask the question, would a similarly set up LHT and Pacer be roughly the same speed?

................but I don't think it will be something troubling me on my death bed.

Thanks again for troubling.

Best post on that page is from Bez........who mentions the elephant in the room......
....a big, tall, strong lad needs a frame with much bigger diameter tubes than does a small, short rider.
Comparisons are always odious.

[Keezx]

PS:

I wish I could measure the pedal pressure or the muscle effort to go along on one bike vs the other. We could then quantify the power requirements.

IF you're really interested, pedal based power meters do exist.

[Mick F]

Yes, at a high cost.
http://www.wiggle.co.uk/garmin-vector-2 ... wer-meter/

I was thinking about borrowing a pair.

[urbanhiker]

Been pondering this question ever since I started riding bikes. And upped my interest since I've been looking to buy a new long distance do-it-all bike.

As with many things cycling related, utterly gob-smacked at how little this seems to have been studied. But did stumble across this, almost scientific experiment the other day. See link.

http://www.cyclingweekly.com/videos/cycling-tech/how-much-speed-can-you-buy-video

[Keezx]

I think that 80% of that difference is by using a triathlon bar versus a normal drop bar.

[swscotland bentrider]

There is a lot of sense among the posts on this topic. I agree that psychology, suspension, aerodynamics, rolling resistance and weight all play a part.
My sportiest conventional bike is a Croix de Fer. c.12Kg. I like it a lot. My sportiest recumbent is a Nazca Gaucho 28. c.15Kg. Whenever I go out on the Croix de Fer my initial feelings are along the lines of 'this is (by comparison) so responsive and so much better up hills why do I bother with the 'bent'? And on a short run it is, overall, the quicker bike. However on a long ride, unless very hilly, I reckon I would end up a bit faster on the bent. When I arrive home from a run on the 'bent I feel less beaten up, apart from the legs that is. Being comfortable conserves energy.

My other 'bent and my Airnimal folder are on 24" (507) wheels / Kojak slicks. On the driveway, the small wheel bikes roll slightly less easily than the Gaucho and that has to be down to wheel size and tyres.

[mig]

so a bike is 'faster' if it is more efficient to get up to speed for a given amount of input and better maintains that speed over time...?

question. if i have ,say, a 531 frame and attach a modern, stiff carbon crankset to it am i likely to be bending the frame more than ideal instead of propelling myself forward? are components of an age matched to the frames of the same age?

[Keezx]

I wouldn't bother at all about stiffness.
It's all stiff enough except old ALAN frames.

[pwa]

One of the main attributes of a fast bike is that it is working properly with great hubs, wheels that are true, and brakes that work well enough to inspire confidence.

Another key attribute is that you feel at home on it, and find pedaling and cornering natural. That's a combination of good fit and appropriate geometry.

Getting your head low reduces frontal area and makes you able to go through the air quicker, but take that too far and discomfort will slow you down before long. So the fastest bike over ten miles will probably have the bars lower than the fastest bike over a hundred miles. Over longer distances a tolerable saddle makes you faster.

Bike weight matters a bit, but not as much as some think.