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29er Crosscountry, what's the best configuration?



 
 
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  #1  
Old August 19th 03, 10:00 PM
onewheeldave
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Default 29er Crosscountry, what's the best configuration?


I've never used 150's on my 29-er but from what others have posted
you'll lose some speed.

On smooth trails I find that high tire pressure makes for a much better
ride, but if some parts of your course are full on muni maybe it's worth
taking a pump and vary air pressure according to terrain.

Sorry I can't be much help but at least it'll bump the thread to the top
and maybe someone with more experience can reply; I'd be interested
myself in peoples experiences of 150's on a 29-er as I've contemplated
trying it myself.


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  #2  
Old August 19th 03, 10:14 PM
jagur
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Default 29er Crosscountry, what's the best configuration?


i'd run up the pressure to about 65psi,you dont want a pinch flat in a
race and on a 29er its a big possibilty since the rims are so skinny.

your tyre wont be rolling over at that pressure either,but watch for
jagged rocks since the side walls are made so thin.(slice)

150's are a good idea for offroad,and over all they are faster since its
hard to maintain the top speed that 125's give because the terrain is
always changing in favor of more leverage on the wheel.(whew!)

150 is the limit i'd say anything longer would negate the advantage of
the 29 inch wheel.


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  #3  
Old August 19th 03, 10:40 PM
Mikefule
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Default 29er Crosscountry, what's the best configuration?


You'll need to practise and find out, and you'll need to know a bit
about the course.

I ride a Coker on 150s, a 28 on 110s, and a 26 on 150s.

The Coker will roll up short hills which would stop the 26. However, if
the hill's too long for the Coker's momentum to rush it up , then the 26
can usually plod and grind up. meanwhile, the 28 is so light that it
will sometimes beat both the Coker and the 26 on a smooth hill, even
though it has the shortest cranks and highest gear ratio.

So, long hills need long cranks; short hills can sometimes be 'rushed'
with shorter cranks and more speed.

Downhill, there is no substitute for leverage. I think a good handle is
worth 10% or so on your crank length.

I find 150s painfully slow on a 28. 125s are more fun, and 110s are
best for general and road use. Try the 125s. There is no right answer,
though, and there is no substitute for doing the miles.

Good luck.


--
Mikefule - Roland Hope School of Unicycling

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  #4  
Old August 20th 03, 12:22 AM
Tom Holub
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Default 29er Crosscountry, what's the best configuration?

In article ,
jagur wrote:
)
)i'd run up the pressure to about 65psi,you dont want a pinch flat in a
)race and on a 29er its a big possibilty since the rims are so skinny.

I don't see why a skinny rim would be more likely to cause a pinch flat.
A pinch flat is caused when the tire pressure isn't high enough to keep
the ground from contacting the rim--this is a function of air volume and
tire sidewall, not rim width.

At 190 pounds plus gear, I run my NanoRaptor at 40 psi off-road
without bottoming it out. When it goes below 40 I start to bottom it.
(See Nick Brazzi's Moab video).

)150's are a good idea for offroad,and over all they are faster since its
)hard to maintain the top speed that 125's give because the terrain is
)always changing in favor of more leverage on the wheel.(whew!)
)
)150 is the limit i'd say anything longer would negate the advantage of
)the 29 inch wheel.

A 29er with 170s is much, much faster than a Gazz with 170s on smooth
trails and fire roads.
-Tom

  #5  
Old August 20th 03, 01:38 AM
jagur
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Default 29er Crosscountry, what's the best configuration?


Tom Holub wrote:
*
I don't see why a skinny rim would be more likely to cause a pinch
flat.
A pinch flat is caused when the tire pressure isn't high enough to
keep
the ground from contacting the rim--this is a function of air volume
and
tire sidewall, not rim width.*

hog wash,

take two wheels with the same psi in them,the thinner rim will drive
through the middle of the tyre easier than a wider rim.


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  #6  
Old August 20th 03, 02:04 AM
Tom Holub
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Default 29er Crosscountry, what's the best configuration?

In article ,
jagur wrote:
)
)Tom Holub wrote:
) *
) I don't see why a skinny rim would be more likely to cause a pinch
) flat.
) A pinch flat is caused when the tire pressure isn't high enough to
) keep
) the ground from contacting the rim--this is a function of air volume
) and
) tire sidewall, not rim width.*
)hog wash,
)
)take two wheels with the same psi in them,the thinner rim will drive
)through the middle of the tyre easier than a wider rim.

Well, perhaps that's true for fat enough tires, but you certainly don't
have to run the NanoRaptor at 65psi to avoid pinch flats, even on Slickrock.
-Tom
  #7  
Old August 20th 03, 03:20 AM
unibabyguy
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Default 29er Crosscountry, what's the best configuration?


I would choose 150s myself, since it's much easier to accelerate when
you're getting pitched around on the bumps. I have used 125s offroad
but it's a lot of work trying to avoid UPDs.

You may also want to consider 150s with a 24x3 tire. I prefer that
combo to anything with the 29" since it's much better at dealing with
the bumps. If you're only going 5-6 miles the increased rolling
resistance shouldn't be a big problem.


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  #8  
Old August 20th 03, 04:04 AM
GizmoDuck
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Default 29er Crosscountry, what's the best configuration?


Memphis Mud wrote:
*I'm planning on racing a little duathlon and a little triathlon this
fall. Each will have 5 or 6 miles of crosscountry with a smattering of
real MUni spots. (2 out of 6 miles are tricky, the rest is less
technical)

I want to use my Yuni 29 cuz its faster in the flats

Nanoraptor 2.1 x 29
125 cranks
No brake

Should I put 150s on? or longer? This would make the uphills a bit
easier and I think this helps on the downhills too??? Should I ride
squishy, medium or hard PSI? I like squishy for 3" x 24 MUni. But the
big ole MUni tire compresses evenly. The Nanoraptor tends to fold to
one side...this is weird to the rider.

Any advice is appreciated. Tom. *



I also use a YUni 29er with Nanoraptors, KH seat (5kg/11lb). The
Nanoraptor is surprising good off road even though it doesn't look that
aggressive. It's also light and fast on road.

The 125mm is OK for smooth trails, but I find that once it starts
getting bumpy, every bump that slows you down takes a lot more effort to
accelerate back to speed. The 150mm allows you to power over the bumps.
That said, I find that I save about about 3-4min per hour if I used the
125mm over smooth terrain. On rough (or more precisely, bumpy) terrain
I may be up to 5min slower/hour on 125mm compared with the 150mm cranks
because of the sluggish acceleration.

I like my presures about the same as MTB pressure- not too low as the
Nanoraptor can track a little funny if it's too soft.

In short- rough/bumpy/lumpy terrain: Go 150mm
Smooth/fast: Go 125mm

You don't need a brake if you are racing- technical steep downhills may
be just as fast to run down.

Be careful if you're wearing baggy shorts- you can snag on the YUni fork
and wipe out badly at high speed.

The 29'er is great for duathlon- I did one early this year and I must
have passed half the MTBkers on the 40minute hillclimb- given the right
gradient a unicycle is more efficient than a bike. Once I got to the
run I was able to transition quickly because I didn't need to change out
of clipless pedals.

Keep it light and keep it fast


--
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Tony on the NZUni weekend

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James on the NZuni weekend

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  #9  
Old August 20th 03, 09:34 PM
joemarshall
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Default 29er Crosscountry, what's the best configuration?


I'd ride with 125s, most cross country mtb racing terrain isn't
difficult enough to warrant 150s for anything other than steep bits. If
you're racing you'll run faster up anything you can't ride up with 125s.
Practice lots on 29er and you'll be fine over bumpy stuff even with
shorter cranks.

Don't even think about 24x3 if you're racing, they're slow slow slow
even if you don't have mega cranks. 26x2.6 is okay, but a 29er really
rules over all the super-fat muni tyres for almost any bike race.

Short cranks and big wheel make you much faster downhill until the point
at which you don't dare stay on, you can ride big bombholes on them and
everything if you're not a scaredycat like I am.

I think a 29er with micro cranks + brake would be good for races with
sustained downhill as you can definately ride faster than you can run,
but you do sometimes spin out without a brake.

Joe


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  #10  
Old August 21st 03, 12:03 PM
onewheeldave
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Default 29er Crosscountry, what's the best configuration?


Joe,

Have you ridden 29-er with both 125's and 150's, if so how much
smoothness/speed is lost with the 150's?

I'm quite surprised to find that I'm getting able to tackle some of the
bumps and hills on my 29-er that I was doing on the muni; my main
difficulty is that I'm not happy about attempting uphill freemounts on
it.

I've got a pair of 150's ready to try but want to spend some more days
pushing it with the 125's so I'm just gathering opinions in the
meantime.


--
onewheeldave - Semi Skilled Unicyclist

"He's also been known to indulge in a spot of flame juggling - but it's
the Muni that really fires him up."

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