Mountain Bike or upgrade to go faster?

Question

I have a mongoose mountain bike, its not fast enough. The highest gear does not allow me to push the bike to go faster because im still pedeling quite a bit. Do all bikes come with the same gear shifts or can I find one that will allow me to peddle slow, push hard and go faster.

Answer 1

if you want  to go fast get a road bike with alot of gears

Answer 2

I fully understand your problem, (unlike sfr1224 who seems to think you may require a lower gear!) (maybe they have never reached their highest gear!)

I too can easily out pedal my highest gear ratio of 46/12 (front/rear), and for those stating mountain bikes are built for offroad, well i even find this a problem on downhill paths.

I have previously used 50/12 which for me suits me fine. I then find I have enough to continue, on a lighter bike I would opt for even higher, but my bike is almost 20 years old!

When i last broke a front mech, i returned to a 46 chain ring on the front as the newer front mech will not cope with the large teeth difference between smallest and largest chain rings.

I am now going back to a 50 on the largest ring, a 40 on the middle (modified from an outer 40 toother (who rides that slow!) now looking for about a 30 to replace my smallest ring. Although 20-22 seems to the norm! Even my granny used to use larger. Moutain bikers are getting soft! (Find some steeper hills). I used my first gear (eer once!)

Answer 3

You would need a bigger, larger front chain ring, which would give you a bigger high gear.  I have a 60 tooth chain ring on one of my bikes and the small cog is a 12 tooth so with a 60 / 12 gear ratio that means for every revolution of the pedals, the wheel turns five and half times.  

The chain ring is made by Paragon Machine Works.  I tried a 66 tooth ring and that was the size of a dinner plate but that was too big.  Couldn't really get up to speed.  The light at the bottom of the hill didn't help either.

Your big ring now is probably 48 to 46 teeth.  Try a 50-54 tooth ring, but the bolt circle has to match.

Problem:  You have to lengthen the chain, your shifting may suffer even with modifications, you have to move the front deraileur up and will lose the use of the smallest inner chainring.  You may have to buy a new housing and shifter cable to accomodate the deraleur's new position.  You might have chain rub against some components.  The extra stress will wear out the small cogs faster.  

Now what you could do is have the big ring, small cog full time, but that's hard on the knees and makes the bike impractical.

Answer 4

A mountain bike is designed for off-road riding.  To this end, they typically have 26" wheels and pretty low gears.  Thus, it is often easy to "spin out" a mountain bike's gears on a road (especially going down hill).  A road bike has larger wheels and higher gears.  You've got to be going pretty fast to spin out a road bike.

The fact of the matter, though, is you'll actually go faster for a longer period by "spinning" the pedals rather than "mashing" them.  Most people pedal most efficiently between about 60-100 RPM.  You want to find the gear that allows you to spin the pedals without a lot of effort at a high but comfortable cadence.  If your legs muscles are burning, you need to shift to a lower gear.  If you feel your heart racing and your lungs are burning, you need to shift to a higher gear.  When you are right in between muscles burning and your heart/lungs burning you have the perfect gear and cadence.

Excessive mashing is pretty tough on the knees.  If you ever get off your bike and have sore knees, it may indicate you are try to muscle your bike too much.

It might be helpful to work on your high speed pedaling skills.  If you develop a nice, smooth round pedal stroke, you should be able to easily pedal upto 120 RPM without having your bottom bouncing off the seat.  This should allow you to pedal at least 30mph on your mountain bike.

Hope this helps.