MTB speed increase ideas

Hi all,

A friend of mine just got his first MTB. It's an entry-level beast,
and used for commuting right now. My friend wants to extract more
speed out of the thing. I checked it out, and his gearing is one
culprit....a 42T large ring and a 12T sprocket is his fastest gear
combination.

He took it back for a tune-up (general sporting goods store), and they
indicated something about using a 9T or 10T sprocket!?! Does such a
thing even exist? I told my friend to forget about it, but it piqued
my curiosity....

In the meantime, I've got a cassette with an 11T sprocket to 'upgrade'
his bike, and I'll suggest a chainring swap from a 42T to a 44T. This
will buy him a little more speed.

Are there any other obvious speed improvements to be made? Slicks will
reduce rolling resistance, but I'm reluctant to suggest them because
the bike will still be used for some light-duty off-road use. Since
the speed problem is due to him 'spinning out', slicks won't
appreciably change his top speed anyway.

Can anyone recommend a suitable semi-slick that can be used for
fire/gravel roads and/or light trail use?

Cheers,
Dave

wrote:
Hi all,

A friend of mine just got his first MTB. It's an entry-level beast,
and used for commuting right now. My friend wants to extract more
speed out of the thing. I checked it out, and his gearing is one
culprit....a 42T large ring and a 12T sprocket is his fastest gear
combination.

He took it back for a tune-up (general sporting goods store), and they
indicated something about using a 9T or 10T sprocket!?! Does such a
thing even exist? I told my friend to forget about it, but it piqued
my curiosity....

Any sprocket less that 13 teeth is stupid. It wears too fast, and the
percentage change in gearing from one to the next is too great for
fine-tuning your cadence. The only reason it is acceptable on a road
bike is that you are working with a 53 or 54 tooth chainring and so the
relative change in ratios are still almost acceptable. With a 42 or 44
in the front, you are about 10% change from cog to cog.


In the meantime, I've got a cassette with an 11T sprocket to 'upgrade'
his bike, and I'll suggest a chainring swap from a 42T to a 44T. This
will buy him a little more speed.


Just get a 48 tooch chainring. 44 is a very small change from 42: 5%
That is less than the value of going from 14 to a 13 for instance. It
is equivalent to shifing from a 22 to a 21 in the rear: a small gear
change.

Are there any other obvious speed improvements to be made? Slicks will
reduce rolling resistance, but I'm reluctant to suggest them because
the bike will still be used for some light-duty off-road use. Since
the speed problem is due to him 'spinning out', slicks won't
appreciably change his top speed anyway.

Say what? "Spinning out" is not a problem for someone who can spin. I
can spin 150 RPM at a road speed of 25 MPH and keep at it for 20
minutes. It takes practice. Knobbies make a lot of wind resistance as
well as tread squirm. If you want to go fast, you have to reduce drag.
Jsut remember that slicks lower you gear ratios noticably and you need
bigger chainrings to compensate.

Can anyone recommend a suitable semi-slick that can be used for
fire/gravel roads and/or light trail use?


Get a road bike. :-)

I ride a road bike with road racing tubulars on gravel and dirt roads
all the time. You don't need some specialty tire to do that.
Mountainbikes are overkill for what your friend is riding on.

Have you ever watched Paris-Roubaix? Makes typical mountainbikes look
like extreme overkill.

On my mountainbike, I have a campagnolo road crankset with 39/53
chainrings. That is one way to get "extra speed" as you call it.
(Actually, just extra gearing). But some mountainbike frames are so
chunky that the 53 tooth chainring will hit the chainstay if you have a
normal bottom bracket.

wrote in message
ups.com...
Hi all,

A friend of mine just got his first MTB. It's an entry-level beast,
and used for commuting right now. My friend wants to extract more
speed out of the thing. I checked it out, and his gearing is one
culprit....a 42T large ring and a 12T sprocket is his fastest gear
combination.

He took it back for a tune-up (general sporting goods store), and they
indicated something about using a 9T or 10T sprocket!?! Does such a
thing even exist? I told my friend to forget about it, but it piqued
my curiosity....

In the meantime, I've got a cassette with an 11T sprocket to 'upgrade'
his bike, and I'll suggest a chainring swap from a 42T to a 44T. This
will buy him a little more speed.

Are there any other obvious speed improvements to be made? Slicks will
reduce rolling resistance, but I'm reluctant to suggest them because
the bike will still be used for some light-duty off-road use. Since
the speed problem is due to him 'spinning out', slicks won't
appreciably change his top speed anyway.

Can anyone recommend a suitable semi-slick that can be used for
fire/gravel roads and/or light trail use?

Cheers,
Dave


Perhaps cycle continuously uphill?
I jest of course however i was wondering what the primary function of his
riding is? if its a fitness thing and weight of the bike isn't an issue then
perhaps somehow (i'll muse on exactly how) add weight to the bike, in a
balanced matter of course. This would both stop him 'spinning out' as
quickly and if he's able to push the extra weight at a high ratio his top
speed would be significantly increased. this might cause braking/breaking
issues mind.

"bill" wrote: Any sprocket less that 13 teeth is stupid. It wears too
fast, and the percentage change in gearing from one to the next is too great
for fine-tuning your cadence. The only reason it is acceptable on a road
bike is that you are working with a 53 or 54 tooth chainring and so the
relative change in ratios are still almost acceptable. (clip)
^^^^^^^^^^^^^^^
Sorry, but the relative change in ratios is not affected by the size of the
chainrings. The change from 12 T to 10 T would be 17%.

bill wrote:

... "Spinning out" is not a problem for someone who can spin.
I can spin 150 RPM at a road speed of 25 MPH and keep at it for 20
minutes.

Clark Kent Baka! LOL Bill, I'd pay money to see you spin 150 RPM for
/half/ a minute! (This on the purple girl's Huffy or another marvel of
rolling efficiency?)

It takes practice. Knobbies make a lot of wind resistance as
well as tread squirm. If you want to go fast, you have to reduce drag.
Jsut remember that slicks lower you gear ratios noticably and you need
bigger chainrings to compensate.

Someone else can take that one.

I ride a road bike with road racing tubulars on gravel and dirt roads
all the time.

Ah, yes, the off-road centuries in blue jeans. Maybe Neil Diamond can do a
song about you!

"Bull**** on the rocks...ain't no surprise.

Just pour me a drink, and I'll tell you some lies"

Might be a hit! LOL

wrote:
Hi all,

A friend of mine just got his first MTB. It's an entry-level beast,
and used for commuting right now. My friend wants to extract more
speed out of the thing. I checked it out, and his gearing is one
culprit....a 42T large ring and a 12T sprocket is his fastest gear
combination.

He took it back for a tune-up (general sporting goods store), and they
indicated something about using a 9T or 10T sprocket!?! Does such a
thing even exist? I told my friend to forget about it, but it piqued
my curiosity....

In the meantime, I've got a cassette with an 11T sprocket to 'upgrade'
his bike, and I'll suggest a chainring swap from a 42T to a 44T. This
will buy him a little more speed.

Are there any other obvious speed improvements to be made? Slicks
will reduce rolling resistance, but I'm reluctant to suggest them
because the bike will still be used for some light-duty off-road use.
Since the speed problem is due to him 'spinning out', slicks won't
appreciably change his top speed anyway.

Can anyone recommend a suitable semi-slick that can be used for
fire/gravel roads and/or light trail use?

Maybe buy some semi-slicks; they'll /feel/ faster and more lively than
knobbies on pavement and gravel surfaces. Otherwise, don't waste money
trying to "improve" an entry-level mountain bike! The best way to "extract
more speed out of the thing" is for your friend to get stronger and better.
Then, sooner than later, he'll want a "good bike" and this can become his
beater.

Sorno

In article . com,
" writes:

Are there any other obvious speed improvements to be made? Slicks will
reduce rolling resistance, but I'm reluctant to suggest them because
the bike will still be used for some light-duty off-road use. Since
the speed problem is due to him 'spinning out', slicks won't
appreciably change his top speed anyway.

Can anyone recommend a suitable semi-slick that can be used for
fire/gravel roads and/or light trail use?

Some folks like Continental Town & Country tires for such purposes.
These have an inverse tread. I've read some complaints of
inverse tread tires being lousy mudders, though. I expect they'd
be no worse than slicks on slippery mud (or wet grass for that matter.)
They should be okay on dry hardpack and finer gravel than egg gravel.
There are other brands of inverse tread MTB tires as well. IIRC,
Kenda and Cheng Shin make some.


cheers,
Tom

--
-- Nothing is safe from me.
Above address is just a spam midden.
I'm really at: tkeats [curlicue] vcn [point] bc [point] ca

wrote:

In the meantime, I've got a cassette with an 11T sprocket to 'upgrade'
his bike, and I'll suggest a chainring swap from a 42T to a 44T. This
will buy him a little more speed.

Tell him to pedal faster. 42/12 on an MTB gets you up to 25 mph with a
normal cadence (90 to 95 rpm). If he needs to go faster than that on an
MTB with offroad tyres he must be some beginner.

Can anyone recommend a suitable semi-slick that can be used for
fire/gravel roads and/or light trail use?

I'd get tyres by a major brand like Continental or Schwalbe with a smooth
center of the tread. They're likely to roll a lot better than whatever
the bike came with.

-as

On Mon, 17 Jul 2006 15:47:59 GMT, "Bill Sornson"
wrote:

bill wrote:

... "Spinning out" is not a problem for someone who can spin.
I can spin 150 RPM at a road speed of 25 MPH and keep at it for 20
minutes.

Clark Kent Baka! LOL Bill, I'd pay money to see you spin 150 RPM for
/half/ a minute! (This on the purple girl's Huffy or another marvel of
rolling efficiency?)

It takes practice. Knobbies make a lot of wind resistance as
well as tread squirm. If you want to go fast, you have to reduce drag.
Jsut remember that slicks lower you gear ratios noticably and you need
bigger chainrings to compensate.

Someone else can take that one.

I ride a road bike with road racing tubulars on gravel and dirt roads
all the time.

Ah, yes, the off-road centuries in blue jeans. Maybe Neil Diamond can do a
song about you!

"Bull**** on the rocks...ain't no surprise.

Just pour me a drink, and I'll tell you some lies"

Might be a hit! LOL


Sorni, I think this is a different "Bill."

R Brickston wrote:
On Mon, 17 Jul 2006 15:47:59 GMT, "Bill Sornson"
wrote:

bill wrote:

... "Spinning out" is not a problem for someone who can spin.
I can spin 150 RPM at a road speed of 25 MPH and keep at it for 20
minutes.

Clark Kent Baka! LOL Bill, I'd pay money to see you spin 150 RPM
for /half/ a minute! (This on the purple girl's Huffy or another
marvel of rolling efficiency?)

It takes practice. Knobbies make a lot of wind resistance as
well as tread squirm. If you want to go fast, you have to reduce
drag. Jsut remember that slicks lower you gear ratios noticably and
you need bigger chainrings to compensate.

Someone else can take that one.

I ride a road bike with road racing tubulars on gravel and dirt
roads all the time.

Ah, yes, the off-road centuries in blue jeans. Maybe Neil Diamond
can do a song about you!

"Bull**** on the rocks...ain't no surprise.

Just pour me a drink, and I'll tell you some lies"

Might be a hit! LOL


Sorni, I think this is a different "Bill."

Rats. You're right, of course. The "road racing tubulars" should have
tipped me off, but that spinning 150 RPM for 20 minutes is just so...BAKA!

My apologies, Iron Bill. Hope you liked the song, at least