13 teeth cog , any huge difference, while trying to reach 25mph

Tony Chopper-Kun

On 9 speed, there are 11- 12- 14 - 16 .... - 32 for wide range 11-32

then 11 - 12 - 13 -14- 16 ... - 28 for close spacing range 11-28

for cyclocross 35mm tyre , 85 psi or 25mm / 28mm tyre, even on rough road

will i ever get to 25mph on the road? and i been using 28 on hill on my other road bike, but I haven't tried 28 on steep hill / haven't been testing 32 really much


is it huge difference that it is easier to jump from 14 to 13 to 12 rather than 14 to 12?

sungod

it's simple arithmetic, relative effort is proportional to cog size for a given cadence

14 to 12 will need c. 14% more effort (2/14)
14 to 13 will need c. 7% more effort (1/14)

in general, higher cadence is easier on the knees, if you need a 32 regularly then i'd go with the cassette with 32 and not worry about the smaller cogs

cougie

A cyclo cross tyre? That will slow you down.
A slick tyre will be easier to get up to speed.

It's not the gearing - more likely your legs.

giropaul

Ray Booty was the first to go under 4 hours for 100 miles - on a fixed gear which was probably around the mid 80 inches. It's your ability to pedal, not a the gear

Tony Chopper-Kun

cougie wrote:

A cyclo cross tyre? That will slow you down.
A slick tyre will be easier to get up to speed.

It's not the gearing - more likely your legs.

That guy on youtube with cyclocross on 35mm riding too fast on flat road, so i choose continuel cyclocross speed folding tyre for a piece of mind on any terrain and rough road. They mostly fast rolling on hard ground. They weighs 350g compared to 250g on 28mm road tyre with 150 tpi both of each.

Too much impact on 28mm road tyre seem bad to me, and i find safety / traction more safer and comfortable. big holes and gap on road --> too much hazard to avoid

darkhairedlord

tyres decent on put must you. Glasses for the hazard seeing you wear must.

darkhairedlord

Good luck with cruising at 25mph if you can't manage the jump from the 14 to the 12 tooth.

trailflow

Tony what size are you front chainrings ?

Tony Chopper-Kun

trailflow wrote:

Tony what size are you front chainrings ?

50 / 34

darkhairedlord

The only things slowing you down are the tyres and the rider.

trailflow

Then you have enough gears to reach 25mph on the flat. The only thing preventing you is your legs and your power output. As you go faster the wind resistance increases making a little harder but that wont stop you reaching 25mph. All tyre sizes (23,25,28,35c) can reach 25mph if you are strong enough.

a 50t chainring with an 11t cog at 90 cadance is 32.2 mph. (25c)

a 50t chainring with an 12t cog at 90 cadance is 29.5 mph. (25c)

a 50t chainring with an 13t cog at 90 cadance is 27.3 mph. (25c)

a 50t chainring with an 14t cog at 90 cadance is 25.3 mph. (25c)

You dont really need a 13t cog. You can acheive 25mph with a 14t cog

Tony Chopper-Kun

trailflow wrote:

Then you have enough gears to reach 25mph on the flat. The only thing preventing you is your legs and your power output. As you go faster the wind resistance increases making a little harder but that wont stop you reaching 25mph. All tyre sizes (23,25,28,35c) can reach 25mph if you are strong enough.

a 50t chainring with an 11t cog at 90 cadance is 32.2 mph. (25c)

a 50t chainring with an 12t cog at 90 cadance is 29.5 mph. (25c)

a 50t chainring with an 13t cog at 90 cadance is 27.3 mph. (25c)

a 50t chainring with an 14t cog at 90 cadance is 25.3 mph. (25c)

You dont really need a 13t cog. You can acheive 25mph with a 14t cog

i don't know how fast is cadence 90rpm, but i cycle 17-20mph on 14t cog, roughly about 70rpm

lostboysaint

20 rpm quicker than you pedal.

trailflow

Then 25mph should well be within your reach. Aim for 100rpm cadence. Buy a computer with a cadence sensor.

Tony Chopper-Kun

trailflow wrote:

Then 25mph should well be within your reach. Aim for 100rpm cadence. Buy a computer with a cadence sensor.

any speed above 20mph, does pedalling get exponentially hard since aero drag? plus the slight gradient slope

webboo

Tony Chopper-Kun wrote:

trailflow wrote:

Then 25mph should well be within your reach. Aim for 100rpm cadence. Buy a computer with a cadence sensor.

any speed above 20mph, does pedalling get exponentially hard since aero drag? plus the slight gradient slope

Nope it gets hard because its hard.

pblakeney

Tony Chopper-Kun wrote:

trailflow wrote:

Then 25mph should well be within your reach. Aim for 100rpm cadence. Buy a computer with a cadence sensor.

any speed above 20mph, does pedalling get exponentially hard since aero drag? plus the slight gradient slope

Yes.
The increases are geometric, not linear.

trailflow

any speed above 20mph, does pedalling get exponentially hard since aero drag? plus the slight gradient slope

Only in a 50mph headwind

ajwcyclist

You should work on upping your cadence and save your knees. Also it will keep you fresher upping your cadence will help to stop heavy legs
On a ride of 1 hour on flat roads aim to keep your cadence between 100-110 to get used to spinning the legs faster and using that muscle group. Another think is ride 30 minutes at 100-110 heart rate z2 , then 15 minutes around 50 zone 3 for strength. Then repeat the first 30 minutes

simon_masterson

You are overcomplicating something very simple. Using a gear calculator will tell you what gear you need to ride at your desired speed at your preferred cadence, or you could just use your cycle computer to tell you how fast you are going. It doesn't make a huge amount of difference whether or not you have a 13t sprocket.

milemuncher1

ajwcyclist wrote:

You should work on upping your cadence and save your knees. Also it will keep you fresher upping your cadence will help to stop heavy legs
On a ride of 1 hour on flat roads aim to keep your cadence between 100-110 to get used to spinning the legs faster and using that muscle group. Another think is ride 30 minutes at 100-110 heart rate z2 , then 15 minutes around 50 zone 3 for strength. Then repeat the first 30 minutes

:shock: