New Mountain bike very slow on highest gear

[Rubzczo]

Hi Guys,

I'm quite new to cycling. This is probably a silly question but my new bike feels like I get little peddling resistance on the higher gears meaning I'm always going very slow. The bike is a carrera and has 21 gears. I'm not a great cyclist at all with average leg strength. When going slightly downhill even on the highest gear the bike will coast and peddling doesn't catch or do anything.

 

[vickster]

Are you in the big chain ring by the pedals? And near the smallest cog on the back wheel. Those should be resistant enough. Post some photos of the rings and cogs and what bike is it?

 

[Smokin Joe]

Is this a wind up?

 

[fossyant]

You should be pedalling around 70 to 100 rpm, and select gears as necessary.

 

[ColinJ]

You might be misunderstanding 'high gear' as being 'high up the cogs at the back'. In fact, the highest gear at the back is the lowest (smallest) of the cogs. (Highest at the front is what you might expect, as vickster suggested - the biggest ring.)

You will NOT find the combination of biggest at the front and smallest at the back easy!

 

[Ajax Bay]

When going slightly downhill even on the highest gear the bike will coast and peddling doesn't catch or do anything.

Tell us how many teeth your largest chainring and your smallest (at the rear) sprocket have.
Remember it's a 'mountain bike' so geared to allow the rider to climb steep slopes rather than blasting downhill on roads.
To provide an idea of the spectrum a 'typical' road bike will have gear ratios from 1.2 to 4.6 and an MTB (maybe like yours) might have 0.7 to 3.7.
http://www.gear-calculator.com/?GR=...24,27,30&UF=2215&TF=90&SL=2.6&UN=KMH&DV=ratio