Would a road bike be quicker?

[jeltz]

OK I know that road bikes are quicker than hybrids but looking at the Focus Arriba 2009 from wiggle I wonder what advantages an aluminium framed road bike would have. Briefly the speck is:-

Crankset FSA Vero Triple 52/42/30T
Cassette Shimano Sora 8 speed, 12-25T
Tyres Schwalbe Speed Crusiser, puncture protection 700x30c
Weight 11.1 kgs

My trouble is that I want to ride the local (rough) cycle routes and use the bike for quick shopping trips with a rack and pannier as well as head out with the local CTC on their Sunday rides and keep up with them on their road bikes. I can just about manage to do that on my Halfords/Raleigh MTB with slicks but the gearing isn't good.

 

[HJ]

Lighter will be quicker, but at the end of the day it is how good your legs are that will really make the difference...

 

[PK99]

OK I know that road bikes are quicker than hybrids but looking at the Focus Arriba 2009 from wiggle I wonder what advantages an aluminium framed road bike would have. Briefly the speck is:-

Crankset FSA Vero Triple 52/42/30T
Cassette Shimano Sora 8 speed, 12-25T
Tyres Schwalbe Speed Crusiser, puncture protection 700x30c
Weight 11.1 kgs

My trouble is that I want to ride the local (rough) cycle routes and use the bike for quick shopping trips with a rack and pannier as well as head out with the local CTC on their Sunday rides and keep up with them on their road bikes. I can just about manage to do that on my Halfords/Raleigh MTB with slicks but the gearing isn't good.

sounds like you nees a cyclocross type bike - see cycling plus this month

 

[Tynan]

investigate the gearing, mtbs tend to come with gears suited to off road so nothing much in the 20mph plus range

a new block might be suprising cheap and still leave you with plenty in the lower range to handle off road

 

[chris667]

That bike is too cheap, and too high geared. If you have £400 to spend on a bike for the things you're looking to do, you're better looking for quality secondhand than cheap new.
£400 would buy a secondhand tourer that would be in a different league to this. It will save money in the long run too, because you won't have to replace bits as quickly, or want to upgrade it.
Best place to ask is everyone at your club, perhaps one of them wouldn't mind coming to look at some secondhand machines with you? You never know, one of them might have something in their collection.
It's a much better solution than buying a mediocre bike from an anonymous internet company. Buy cheap, buy twice.

 

[jimboalee]

Lighter will be quicker, but at the end of the day it is how good your legs are that will really make the difference...

This is a grey area.

More hills than flat, yes. More flat than hills , maybe. More descents than uphills and flats, no.

 

[I am Spartacus]

as well as head out with the local CTC on their Sunday rides and keep up with them on their road bikes.

???
Does not compute.....

 

[swee'pea99]

This is a grey area.

More hills than flat, yes. More flat than hills , maybe. More descents than uphills and flats, no.

How can you have 'more descents'? What goes down must come up, surely, unless you start and end your ride at different altitudes.

As for its being a grey area, sorry but that's nonsense. Other things being equal, lighter is always faster.

 

[I am Spartacus]

[quote name='swee'pea99'] lighter is always faster.[/QUOTE]

very true.. mainly on the bank account/credit card

 

[jimboalee]

.

I will allow you to have a long hard think about this and maybe refer to some vehicle dynamics principles.

There are a number of variables. Mass ( what were talking about ), Cross section area, tyre rolling resistance and the 'equilibrium velocity' down a slope.

QUICK!! Move this to 'Technical - Fundemantal priciples of how a bicycle works'

 

[jimboalee]

In a nutshell.

If the cross section area remains the same and the tyre rolling resistance remains the same, reducing mass will only result in a lower 'equilibrium velocity' because the vehicle has less Inertia.

The Cd will remain very similar.

Since propulsion power is calculated as a function of Cd x Cross section area ( CdA ), the propulsion power will be similar for a heavier bike. ON THE FLAT.

The disadvantage of a heavy bike will be when m/s^2 is required and up hills.

This is why I say "More flat than hills, maybe".

 

[Hont]

That bike is...too high geared.

Eh? It's a triple with a 30x25 gear at the bottom. Shome mistake shurely.

 

[swee'pea99]

Ok, I've had a long hard think. Other things being equal, lighter is always faster.

 

[accountantpete]

Depends on how stiff the frame/wheels are doesn't it?

 

[swee'pea99]

Other things being equal[/B], lighter is always faster.