MTB low pressure and pinch flats

On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front end is
so heavy that you can't lift them off of the ground with a low gear
so you don't have to stand.


Not really. The front coming off the ground is a common occurrence on a
MTB. There are climbs where I have to not just stand but also bend my
upper body over the handlebar so this does not happen.

Are you talking about full suspension bikes? Maybe on the latest super-light full carbon fiber bikes.

On 2017-05-19 08:24, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front end
is so heavy that you can't lift them off of the ground with a low
gear so you don't have to stand.


Not really. The front coming off the ground is a common occurrence
on a MTB. There are climbs where I have to not just stand but also
bend my upper body over the handlebar so this does not happen.

Are you talking about full suspension bikes? Maybe on the latest
super-light full carbon fiber bikes.


Yes, full sus but mine is a classic aluminum deal and with all the
additions including very thick tubes it weighs around 38lbs:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The seat on MTB is usually far behind the bike's CG and that makes it
rear up. Although my road bike also rears up when I really step on it
upon a traffic light turning green uphill.

--
Regards, Joerg

http://www.analogconsultants.com/

On Friday, May 19, 2017 at 9:28:46 AM UTC-7, Joerg wrote:
On 2017-05-19 08:24, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front end
is so heavy that you can't lift them off of the ground with a low
gear so you don't have to stand.


Not really. The front coming off the ground is a common occurrence
on a MTB. There are climbs where I have to not just stand but also
bend my upper body over the handlebar so this does not happen.

Are you talking about full suspension bikes? Maybe on the latest
super-light full carbon fiber bikes.


Yes, full sus but mine is a classic aluminum deal and with all the
additions including very thick tubes it weighs around 38lbs:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The seat on MTB is usually far behind the bike's CG and that makes it
rear up. Although my road bike also rears up when I really step on it
upon a traffic light turning green uphill.

My Trek x-Bontrager had the seat on or ahead of the CG and you could not get it to lift the front end.

On 2017-05-19 09:49, wrote:
On Friday, May 19, 2017 at 9:28:46 AM UTC-7, Joerg wrote:
On 2017-05-19 08:24, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front
end is so heavy that you can't lift them off of the ground
with a low gear so you don't have to stand.


Not really. The front coming off the ground is a common
occurrence on a MTB. There are climbs where I have to not just
stand but also bend my upper body over the handlebar so this
does not happen.

Are you talking about full suspension bikes? Maybe on the latest
super-light full carbon fiber bikes.


Yes, full sus but mine is a classic aluminum deal and with all the
additions including very thick tubes it weighs around 38lbs:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The seat on MTB is usually far behind the bike's CG and that makes
it rear up. Although my road bike also rears up when I really step
on it upon a traffic light turning green uphill.

My Trek x-Bontrager had the seat on or ahead of the CG and you could
not get it to lift the front end.


Ok, but most modern MTB aren't built that way anymore. Part of the
reason is probably to reduce the risk of an endo.

I also have to do bunny hops very often because of the terrain and I
don't want that to require herculean forces every time.

--
Regards, Joerg

http://www.analogconsultants.com/

On Friday, May 19, 2017 at 11:19:38 AM UTC-7, Joerg wrote:
On 2017-05-19 09:49, wrote:
On Friday, May 19, 2017 at 9:28:46 AM UTC-7, Joerg wrote:
On 2017-05-19 08:24, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front
end is so heavy that you can't lift them off of the ground
with a low gear so you don't have to stand.


Not really. The front coming off the ground is a common
occurrence on a MTB. There are climbs where I have to not just
stand but also bend my upper body over the handlebar so this
does not happen.

Are you talking about full suspension bikes? Maybe on the latest
super-light full carbon fiber bikes.


Yes, full sus but mine is a classic aluminum deal and with all the
additions including very thick tubes it weighs around 38lbs:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The seat on MTB is usually far behind the bike's CG and that makes
it rear up. Although my road bike also rears up when I really step
on it upon a traffic light turning green uphill.

My Trek x-Bontrager had the seat on or ahead of the CG and you could
not get it to lift the front end.


Ok, but most modern MTB aren't built that way anymore. Part of the
reason is probably to reduce the risk of an endo.

I also have to do bunny hops very often because of the terrain and I
don't want that to require herculean forces every time.

I didn't mean Bontrager - I meant Gary Fisher that was reproduced almost exactly by Trek.

It was the AL model just before this one: http://www.ebay.com/itm/Trek-Superfl...AOSwax5Y1d4 X

As you can see the weight of the rider is centered.

On 2017-05-19 15:22, wrote:
On Friday, May 19, 2017 at 11:19:38 AM UTC-7, Joerg wrote:
On 2017-05-19 09:49, wrote:
On Friday, May 19, 2017 at 9:28:46 AM UTC-7, Joerg wrote:
On 2017-05-19 08:24, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The
front end is so heavy that you can't lift them off of the
ground with a low gear so you don't have to stand.


Not really. The front coming off the ground is a common
occurrence on a MTB. There are climbs where I have to not
just stand but also bend my upper body over the handlebar
so this does not happen.

Are you talking about full suspension bikes? Maybe on the
latest super-light full carbon fiber bikes.


Yes, full sus but mine is a classic aluminum deal and with all
the additions including very thick tubes it weighs around
38lbs:

http://www.analogconsultants.com/ng/bike/Muddy3.JPG

The seat on MTB is usually far behind the bike's CG and that
makes it rear up. Although my road bike also rears up when I
really step on it upon a traffic light turning green uphill.

My Trek x-Bontrager had the seat on or ahead of the CG and you
could not get it to lift the front end.


Ok, but most modern MTB aren't built that way anymore. Part of the
reason is probably to reduce the risk of an endo.

I also have to do bunny hops very often because of the terrain and
I don't want that to require herculean forces every time.

I didn't mean Bontrager - I meant Gary Fisher that was reproduced
almost exactly by Trek.

It was the AL model just before this one:
http://www.ebay.com/itm/Trek-Superfl...AOSwax5Y1d4 X

As you can see the weight of the rider is centered.


??

The seat is almost above the rear axle. How can the rider's weight be
centered?

On steep uphill sections of trails that bike will rear up just as much
as mine.

https://www.youtube.com/watch?v=WkS8nzvqfPA

This is in German but the pics show it:

https://www.youtube.com/watch?v=MC0DhR4WfSs

--
Regards, Joerg

http://www.analogconsultants.com/

On Friday, May 19, 2017 at 3:29:49 AM UTC-4, John B. wrote:
Snipped

Yup. I read "rigid frame" and stopped.

But of course the original "mountain bikes" were all solid frame. Of
course they didn't refer to them as MTB's but some of their rides were
rather stimulating :-)
https://www.youtube.com/watch?v=SVWP6VaLtvw

--
Cheers,

John B.

The original mountain bikes were sold and marketed/advertised as "MOUNTAIN BIKES". I guees that M.T.B. stands for Multi-Terrain Bikes.

That video your link is to is blocked here. I can't see it.

Cheers

On Friday, May 19, 2017 at 11:24:21 AM UTC-4, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front end is
so heavy that you can't lift them off of the ground with a low gear
so you don't have to stand.


Not really. The front coming off the ground is a common occurrence on a
MTB. There are climbs where I have to not just stand but also bend my
upper body over the handlebar so this does not happen.

Are you talking about full suspension bikes? Maybe on the latest super-light full carbon fiber bikes.

You can quite easily lift the front end on just about any bicycle if the hill is steep enough and the gear you're using is low enough. Sometimes when i tour on fire/logging/mining roads i'll pack the front end of the bike heavier than the rear just to help keep that front wheel on the ground when there are a lot of short steep climbs to make.Riding uop those hills even at a walking pace 9or slower) is LOT easire than trying to push the loaded bike up them.

YMMV

Cheers

On Fri, 19 May 2017 18:37:09 -0700 (PDT), Sir Ridesalot
wrote:

On Friday, May 19, 2017 at 3:29:49 AM UTC-4, John B. wrote:
Snipped

Yup. I read "rigid frame" and stopped.

But of course the original "mountain bikes" were all solid frame. Of
course they didn't refer to them as MTB's but some of their rides were
rather stimulating :-)
https://www.youtube.com/watch?v=SVWP6VaLtvw

--
Cheers,

John B.

The original mountain bikes were sold and marketed/advertised as "MOUNTAIN BIKES". I guees that M.T.B. stands for Multi-Terrain Bikes.


See http://cbklunkers.com/page.cfm?pageid=13
or google on "Bicycle+Klunker" to find out the origins of mountain
biking.

I assume that they qualified as "mountain bikes" anyway
as they were build to ride down mountains :-)

The original "mountain bikes" weren't ,manufactured, they were home
made. The first commercial made (actually a custom order) "Mountain
Bike" was made in 1979 by Tom Ritchey.

"In 1979 Tom Ritchey of Redwood City, California (50 miles south of
Marin) started building fat-tire frames. From 1980 onward he built
hundreds of fat-tire bike frames each year. These were the first bikes
sold by Gary Fisher and Charlie Kelly, founders of MountainBikes
(later the Gary Fisher Bicycle Company)."


That video your link is to is blocked here. I can't see it.

Cheers
--
Cheers,

John B.

On Fri, 19 May 2017 18:42:39 -0700 (PDT), Sir Ridesalot
wrote:

On Friday, May 19, 2017 at 11:24:21 AM UTC-4, wrote:
On Friday, May 19, 2017 at 7:51:37 AM UTC-7, Joerg wrote:
On 2017-05-19 06:30, wrote:

When you're on a real steep off-road climb you sit. The front end is
so heavy that you can't lift them off of the ground with a low gear
so you don't have to stand.


Not really. The front coming off the ground is a common occurrence on a
MTB. There are climbs where I have to not just stand but also bend my
upper body over the handlebar so this does not happen.

Are you talking about full suspension bikes? Maybe on the latest super-light full carbon fiber bikes.

You can quite easily lift the front end on just about any bicycle if the hill is steep enough and the gear you're using is low enough. Sometimes when i tour on fire/logging/mining roads i'll pack the front end of the bike heavier than the rear just to help keep that front wheel on the ground when there are a lot of short steep climbs to make.Riding uop those hills even at a walking pace 9or slower) is LOT easire than trying to push the loaded bike up them.

YMMV

Cheers

There is a short stretch of road (that I try to avoid) leading from a
parking lot up to the street that is steep enough that one is in the
lowest gear and steep enough that the front wheel coming off the
ground is a real threat. My approach is seated and leaning over the
handlebars.

--
Cheers,

John B.