Difference between 21 and 18 speed mountain bikes

[LS20]

those are the numbers of gears... the more gears you have, the higher resolution there is... though, you can gear each "set" differently--the entire drivetrain can be geared "tall" or "short"... so, really, the Number Of Gears do not tell you how fast a bike is...

for what its worth, my road and mountain bike each has 1 gear and ill keep up with anyone anywhere

 

[DaWhim]

i have a 10 speeds bike.

 

[imported_Neeraj]

Originally posted by: Sukhoi

Originally posted by: oboeguy

Originally posted by: laurenlex

Originally posted by: Neeraj
I'm on a low budget, and I've found this one: http://www.halfords.com/opd_product_details.asp?id=20352&type=0&cat=415. Problem is, instead of being the usual MB, it's a Dirt Jump bike. Will I be able to gtthe seat higher - with my own long seat post? Will this be worse on road than a normal MB?

That would be a TERRIBLE bike for riding around for fitness or transportation. Bikes are made for specific purposes, and that one is for catching air, dropping off ledges, and doing stunts. It is not meant to be pedaled while sitting down. The seat is low so you don't break your nads on a landing.

You need a plain jane, quality, mountain bike with smooth, narrow tires. Any brand will do (Specialized, Trek, Fisher, Kona). They are pretty much the same at the same price point.

If a new bike only has 18 speeds, it's not worthy of being ridden, IMO. The cheapest of the cheap Shimano compontets are 21 speed. 24 or 27 speed is better.

The benefit of all those gears is so your legs are spinning at the perfect RPM's at any given speed. You will also get higher and lower gears, which helps hauling @ss and climing steep hills.

Pony up and spend at least $300 US on a basic mountain bike. NO REAR SUSPENSION. Try and not get front suspension if you won't be off road. It makes the bike heavier, and more expensive. If you ride off road, you must have suspension.

Enough rambling, hope I helped a little.

Well done. Best post so far.

Agreed 100%. And again - NO REAR SUSPENSION IN YOUR PRICE RANGE.

That's pretty good advice. I would prefer a city/hybrid, but they costs are too much for me at this time My current MB is pretty fast, but needs big time repairs which I can't do myself. The cost for repairing might uts make me want to get a new bike. I'm going to ask for the cost tomorrow.

I would really definately prefer a city bike like most of you say. I don't do much off roading but there are occasional times. I will look for some 2nd-hand ones tomorrow online.

Thanks for all the replies!

 

[JulesMaximus]

Originally posted by: ThisIsMatt

Originally posted by: FrankyJunior
Very rarely will you ever use the very top or the very bottom gears so for standard riding it won't make a bit of difference.

I use the top end of my mtb when on road all the time, getting up to over 45mph. I use the low end when offroading quite often as well.

I have 53 teeth on my big chainring on my road bike and 11 on the smallest rear cog. At 42mph (I hit that on Sunday going down a huge hill near my house) I could barely keep up if I pedalled. I seriously doubt you have a 53 on a mtb so you must have been spinning at a cadence of what...130? I can do 100 fairly smoothly. I call shens.

Edit-You sure you have your cycle computer calibrated for the correct wheelsize?

 

[ThisIsMatt]

Originally posted by: JulesMaximus

Originally posted by: ThisIsMatt

Originally posted by: FrankyJunior
Very rarely will you ever use the very top or the very bottom gears so for standard riding it won't make a bit of difference.

I use the top end of my mtb when on road all the time, getting up to over 45mph. I use the low end when offroading quite often as well.

I have 53 teeth on my big chainring on my road bike and 11 on the smallest rear cog. At 42mph (I hit that on Sunday going down a huge hill near my house) I could barely keep up if I pedalled. I seriously doubt you have a 53 on a mtb so you must have been spinning at a cadence of what...130? I can do 100 fairly smoothly. I call shens.

Edit-You sure you have your cycle computer calibrated for the correct wheelsize?

11 rear, 44 front. Yes, steep hill, yes my cyclometer is configured correctly (and I've compared it against my car), yes I'm passing traffic. I don't have clipless, but I do have shoe straps/baskets/whatever you want to call them, and yes it takes a lot of pedalling. FYI, it was 47.6mph to be exact

 

[mercanucaribe]

Originally posted by: otispunkmeyer
BMX ..... who the hell needs more than one gear? take the hills like a man

And look like a circus clown riding a little girl's bike!

 

[Sukhoi]

That is one hell of a hill or you're still shensing us.

 

[Icanoutsmokeany1]

Originally posted by: otispunkmeyer
BMX ..... who the hell needs more than one gear? take the hills like a man

I agree, if you learn to pedal properly BMX will take all your leg power and put it to the wheels and you can go fast as hell. It takes some getting used to and for hills...BMX will leave your calves burnt

 

[ThisIsMatt]

Originally posted by: Sukhoi
That is one hell of a hill or you're still shensing us.

It's a pretty good hill Enough that it has a "Watch downhill speed" sign. Hell, I do mid 30's on this one dirt trail I ride

 

[JulesMaximus]

Originally posted by: ThisIsMatt

Originally posted by: JulesMaximus

Originally posted by: ThisIsMatt

Originally posted by: FrankyJunior
Very rarely will you ever use the very top or the very bottom gears so for standard riding it won't make a bit of difference.

I use the top end of my mtb when on road all the time, getting up to over 45mph. I use the low end when offroading quite often as well.

I have 53 teeth on my big chainring on my road bike and 11 on the smallest rear cog. At 42mph (I hit that on Sunday going down a huge hill near my house) I could barely keep up if I pedalled. I seriously doubt you have a 53 on a mtb so you must have been spinning at a cadence of what...130? I can do 100 fairly smoothly. I call shens.

Edit-You sure you have your cycle computer calibrated for the correct wheelsize?

11 rear, 44 front. Yes, steep hill, yes my cyclometer is configured correctly (and I've compared it against my car), yes I'm passing traffic. I don't have clipless, but I do have shoe straps/baskets/whatever you want to call them, and yes it takes a lot of pedalling. FYI, it was 47.6mph to be exact

Checking this calculator Text, with your chainring/rear cog, 26" tires and 170mm cranks, 120rpms is (only) 37.1mph.

Another source says if you're running a 26" x 2.25" tire (with the standard 2115 mm circumference), you'd have to pedal at 149 rpm to reach that speed, according to the Gearing Calculator built into Cyclistats.

Again, shens.

Now, if you're saying you can coast downhill at that speed? I might be inclined to believe you...it would have to be a pretty steep hill though.

 

[ZOOYUKA]

Originally posted by: nakedfrog
Three speeds
/captainobvious

 

[Saint Nick]

i've had my trek bike since '97 same shifting system and all. it ships like crap though, they never fix it when i ask them..........

 

[conjur]

Originally posted by: nakedfrog
Three speeds
/captainobvious

Took five posts in...this place is slacking!

 

[JulesMaximus]

Originally posted by: conjur

Originally posted by: nakedfrog
Three speeds
/captainobvious

Took five posts in...this place is slacking!

Actually, the difference is one cog on the rear cassette. And it will be one of the middle cogs.

 

[Tommy2000GT]

The difference is that 18 and 21 speed bikes are usually department store walmart types.

Decent bikes are usually 24 or 27 speeds

 

[JulesMaximus]

Originally posted by: Tommy2000GT
The difference is that 18 and 21 speed bikes are usually department store walmart types.

Decent bikes are usually 24 or 27 speeds

Most new mountain bikes have 8/9/10 speed cassettes on the rear wheel and a triple on the front. However, it is possible to get a very good used mtb a few years old with 18 or 21 speeds.

I'd never buy a bike from a department store though. They are junk and anyone who is even semi-serious about riding regularly should stay away from those places. It's analogous to going to a local Mexican fish market to buy caviar.

 

[Don Vito Corleone]

Originally posted by: JulesMaximus

Most new mountain bikes have 8/9/10 speed cassettes on the rear wheel and a triple on the front. However, it is possible to get a very good used mtb a few years old with 18 or 21 speeds.

To be completely accurate, nobody is making 10-speed cassettes for MTBs just yet, and hopefully they never will. 10-speed chains are so narrow that they are unacceptably fragile for off-road use, and the narrow cassette spacing is too sensitive to fouling with mud. Until and unless Shimano pushes bike makers to move to wider rear dropout spacing, I doubt we'll see a 10-speed off-road system.

 

[DivideBYZero]

Originally posted by: Neeraj
I'm on a low budget, and I've found this one: http://www.halfords.com/opd_product_details.asp?id=20352&type=0&cat=415. Problem is, instead of being the usual MB, it's a Dirt Jump bike. Will I be able to gtthe seat higher - with my own long seat post? Will this be worse on road than a normal MB?

Don't get a Halfords Dirt bike for the road. For a start the big fat tyres will have muchos rolling resistance. I run commuter tyres on my XC bike when doing road training.

If you are doing road riding, get a bike designed for the job from your local bike store, NOT Halfrauds.

 

[DivideBYZero]

Originally posted by: LS20
those are the numbers of gears... the more gears you have, the higher resolution there is... though, you can gear each "set" differently--the entire drivetrain can be geared "tall" or "short"... so, really, the Number Of Gears do not tell you how fast a bike is...

for what its worth, my road and mountain bike each has 1 gear and ill keep up with anyone anywhere

There's always one with the single speed...

 

[dainthomas]

Originally posted by: Tommy2000GT
The difference is that 18 and 21 speed bikes are usually department store walmart types.

Decent bikes are usually 24 or 27 speeds

My Diamondback is a 21 speed. I use 3 or 4 at most, and haven't had any problems

 

[DivideBYZero]

FYI OP: This is the SORT of thing you should be looking at. I still suggest you go to your local bike store and see what they can do for you. The advice will be better.

 

[91TTZ]

Man, I must be really slacking with my bike. I'm no hardcore bike rider, so I don't need the newest, top of the line bike.

I have a Fuji Cross Town from the mid/late 80's, don't know much about it other than it looks like a 10 speed with knobby mountain bike-tpe tires. It looks halfway between a mountain bike and a 10 speed. It only has 5 or 6 speeds, but honestly that's more than I ever use.

It pedals so smoothly and rides on the road good. It also can go offroad a bit, although you wouldn't want to jump it or anything like that.

 

[JinLien]

Originally posted by: JulesMaximus
The difference is really in the middle gears. You won't be able to go any faster on a 21 vs an 18 spd bike but you will have more gearing in between your highest and lowest gears. One might not necessarily be any lower or less likely higher geared than the other.

BTW-If you're riding on the road why not get a road bike? Much faster!

There is no difference, unless the chain rings & cassette cogs sizes are larger/smaller. The more gears you have the better gearing ratio you have, however most rider have their favorite spinning speed & up hill/power speed, therefore it is almost a moot point to have more rings than the ones that you need.

Go for a 54 teeth chainring size if you are an animal, however not many people can spin with a 54:11 ratio (chainring:cog).

Or go for a granny 22:34 ratio if you are a baby, however balancing will be a problem.

 

[ThisIsMatt]

Originally posted by: JulesMaximus

Originally posted by: ThisIsMatt

Originally posted by: JulesMaximus

Originally posted by: ThisIsMatt

Originally posted by: FrankyJunior
Very rarely will you ever use the very top or the very bottom gears so for standard riding it won't make a bit of difference.

I use the top end of my mtb when on road all the time, getting up to over 45mph. I use the low end when offroading quite often as well.

I have 53 teeth on my big chainring on my road bike and 11 on the smallest rear cog. At 42mph (I hit that on Sunday going down a huge hill near my house) I could barely keep up if I pedalled. I seriously doubt you have a 53 on a mtb so you must have been spinning at a cadence of what...130? I can do 100 fairly smoothly. I call shens.

Edit-You sure you have your cycle computer calibrated for the correct wheelsize?

11 rear, 44 front. Yes, steep hill, yes my cyclometer is configured correctly (and I've compared it against my car), yes I'm passing traffic. I don't have clipless, but I do have shoe straps/baskets/whatever you want to call them, and yes it takes a lot of pedalling. FYI, it was 47.6mph to be exact

Checking this calculator Text, with your chainring/rear cog, 26" tires and 170mm cranks, 120rpms is (only) 37.1mph.

Another source says if you're running a 26" x 2.25" tire (with the standard 2115 mm circumference), you'd have to pedal at 149 rpm to reach that speed, according to the Gearing Calculator built into Cyclistats.

Again, shens.

Now, if you're saying you can coast downhill at that speed? I might be inclined to believe you...it would have to be a pretty steep hill though.

You really don't think I can pedal 3 revolutions in a second? Maybe you're just slow...get over it

 

[JulesMaximus]

Originally posted by: DonVito

Originally posted by: JulesMaximus

Most new mountain bikes have 8/9/10 speed cassettes on the rear wheel and a triple on the front. However, it is possible to get a very good used mtb a few years old with 18 or 21 speeds.

To be completely accurate, nobody is making 10-speed cassettes for MTBs just yet, and hopefully they never will. 10-speed chains are so narrow that they are unacceptably fragile for off-road use, and the narrow cassette spacing is too sensitive to fouling with mud. Until and unless Shimano pushes bike makers to move to wider rear dropout spacing, I doubt we'll see a 10-speed off-road system.

I wasn't sure about that. Just taking a guess since my road bike has a 10spd cassette. I'm more into road bikes. I have a mtb but I haven't been riding it much lately.