Re: Can Disk Brakes flip you over the handle bars?

[Tom Sherman]

[email protected] aka Mike Schwab wrote:
> On Apr 30, 10:49 pm, TBerk <[email protected]> wrote:
>> Obviously I would assume they could if you clamp down fast enough.
>>
>> I ask because I bruised some rib bones this week when I stomped the
>> front brake and *surprise* I found out later my front rim has a bubble
>> bend in it from (I guess) a pot hole at some recent time.
>>
>> Made for a portion of the rim that just wasn't going to get past the
>> brake pads, not while I was trying to actually use said brakes.
>>
>> It would seem a better setup would be one unaffected by a slightly
>> bent rim, or so I wonder.
>>
>> TBerk
>> it would have been funny if it hadn't hurt so much at the time
>
> Disk brakes have more stopping power and any such 'stomp' can result
> in a flip, not requiring any irregularities. Due to their design,
> recumbents are immune from such a flip.

Recumbents with PROPER weight distribution will skid the front wheel
instead of sending the rider over the bars. Some early bad designs, such
as the Hypercycle, would send the rider off the front under heavy
braking, and had too little weight on the rear wheel for it to provide
much braking.

I often wonder if the Hypercycle and its ilk are responsible for much of
the negative attitudes towards recumbents by certain riders. Certainly,
if a rider's only experience was the ill handling, poor climbing and
poor braking Hypercycle, they would not look kindly on recumbents as a
whole.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

 

[[email protected]]

Tom Sherman wrote:


>>> Obviously I would assume they could if you clamp down fast enough.

>>> I ask because I bruised some rib bones this week when I stomped
>>> the front brake and *surprise* I found out later my front rim has
>>> a bubble bend in it from (I guess) a pot hole at some recent time.

>>> Made for a portion of the rim that just wasn't going to get past
>>> the brake pads, not while I was trying to actually use said
>>> brakes.

>>> It would seem a better setup would be one unaffected by a slightly
>>> bent rim, or so I wonder.

>>> it would have been funny if it hadn't hurt so much at the time

>> Disk brakes have more stopping power and any such 'stomp' can
>> result in a flip, not requiring any irregularities. Due to their
>> design, recumbents are immune from such a flip.

> Recumbents with PROPER weight distribution will skid the front wheel
> instead of sending the rider over the bars. Some early bad designs,
> such as the Hypercycle, would send the rider off the front under
> heavy braking, and had too little weight on the rear wheel for it to
> provide much braking.

I've seen nay recumbents with a small front wheel and cranks and
pedals forward of that wheel. These units will endo easily while the
rider remains firmly in the seat. The advantage is that the rider, if
a bit agile, will land on his feet running. The bike does not fare as
well as it overturns and scraped the road.

> I often wonder if the Hypercycle and its ilk are responsible for
> much of the negative attitudes toward recumbents by certain
> riders. Certainly, if a rider's only experience was the ill
> handling, poor climbing and poor braking Hypercycle, they would not
> look kindly on recumbents as a whole.

Long wheelbase recumbents have a slew of other problems in
maneuverability and climbing rough stuff. Disk brakes are not one of
their problems.

Jobst Brandt

 

[Tom Sherman]

[email protected] aka Jobst Brandt wrote:
> Tom Sherman wrote:
>
>
>>>> Obviously I would assume they could if you clamp down fast enough.
>
>>>> I ask because I bruised some rib bones this week when I stomped
>>>> the front brake and *surprise* I found out later my front rim has
>>>> a bubble bend in it from (I guess) a pot hole at some recent time.
>
>>>> Made for a portion of the rim that just wasn't going to get past
>>>> the brake pads, not while I was trying to actually use said
>>>> brakes.
>
>>>> It would seem a better setup would be one unaffected by a slightly
>>>> bent rim, or so I wonder.
>
>>>> it would have been funny if it hadn't hurt so much at the time
>
>>> Disk brakes have more stopping power and any such 'stomp' can
>>> result in a flip, not requiring any irregularities. Due to their
>>> design, recumbents are immune from such a flip.
>
>> Recumbents with PROPER weight distribution will skid the front wheel
>> instead of sending the rider over the bars. Some early bad designs,
>> such as the Hypercycle, would send the rider off the front under
>> heavy braking, and had too little weight on the rear wheel for it to
>> provide much braking.
>
> I've seen nay recumbents with a small front wheel and cranks and
> pedals forward of that wheel. These units will endo easily while the
> rider remains firmly in the seat.

Absolutely NOT true in my experience of short-wheelbase recumbent
bicycles with proper weight distribution (e.g. RANS Rocket, RANS V-Rex,
RANS Vivo, Lighting P-38, Burley HepCat, Reynolds Wishbone, and of
course the Earth Cycles Sunset).

On my Dragonflyer trike which has the crank ahead of the front wheels, I
can skid both on dry pavement without the rear wheel lifting.

How many modern short-wheelbase recumbent bicycles has Jobst Brandt
ridden to determine that "endos" are likely?

> The advantage is that the rider, if
> a bit agile, will land on his feet running. The bike does not fare as
> well as it overturns and scraped the road.
>
Mr. Brandt must be thinking of the Hypercycle or some other obsolete design.

>> I often wonder if the Hypercycle and its ilk are responsible for
>> much of the negative attitudes toward recumbents by certain
>> riders. Certainly, if a rider's only experience was the ill
>> handling, poor climbing and poor braking Hypercycle, they would not
>> look kindly on recumbents as a whole.
>
> Long wheelbase recumbents have a slew of other problems in
> maneuverability and climbing rough stuff. Disk brakes are not one of
> their problems.
>
Actually, front braking is more of a problem on a long-wheelbase
recumbent than a short-wheelbase recumbent, since it is much easier to
accidentally lock up the front wheel.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

 

[Peter Clinch]

[email protected] wrote:

> I've seen nay recumbents with a small front wheel and cranks and
> pedals forward of that wheel.

My Streetmachine has a 20" front wheel and the cranks ahead of it.

> These units will endo easily while the
> rider remains firmly in the seat.

For some values of "easily"... I find that if I slam on the anchors in
an emergency stop I get both wheels skidding, and no hint of an endo.

> The advantage is that the rider, if
> a bit agile, will land on his feet running. The bike does not fare as
> well as it overturns and scraped the road.

What happens in my direct experience on a Streetmachine is I skid to a
stop, still in the seat, still the right way up and think "!"
For me, direct empirical evidence trumps theory.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net [email protected] http://www.dundee.ac.uk/~pjclinch/

 

[Zebee Johnstone]

In alt.rec.bicycles.recumbent on 02 May 2008 01:44:09 GMT
[email protected] <[email protected]> wrote:
> I've seen nay recumbents with a small front wheel and cranks and
> pedals forward of that wheel. These units will endo easily while the
> rider remains firmly in the seat. The advantage is that the rider, if
> a bit agile, will land on his feet running. The bike does not fare as
> well as it overturns and scraped the road.

Will they?

I've been hard on the picks (front disk even!) on my Giro 20 going
downhill. The back (v-brake) skidded, so I let up, I did my damndest not
to lock the front, and didn't (riding a motorcycle has some advantages)
but the thing showed no sign of an endo I could feel.

Indeed, trying same when I first got the disks didn't get me anywhere.
Locking the front is hard to do when you have trained for years not
to, so maybe I wasn't trying hard enough. Never felt a massive weight
transfer forward, nothing like pulling a stoppie on a motorcycle (which
I have done more than once).

If they will "endo easily" then I must be dreaming...

So I have to ask... have you ridden one? Have you managed to endo it?

If so, how? What did it feel like, when did the weight transfer get so
over rather than forward (hard transfer on a bent feels qualitatively
different to hard transfer on an upright to me), and how fast did you have
to go, and how fast were you going when you managed to get it to go over?


Zebee

 

[Tom Sherman]

Zebee Johnstone wrote:
> In alt.rec.bicycles.recumbent on 02 May 2008 01:44:09 GMT
> [email protected] <[email protected]> wrote:
>> I've seen nay recumbents with a small front wheel and cranks and
>> pedals forward of that wheel. These units will endo easily while the
>> rider remains firmly in the seat. The advantage is that the rider, if
>> a bit agile, will land on his feet running. The bike does not fare as
>> well as it overturns and scraped the road.
>
> Will they?
>
> I've been hard on the picks (front disk even!) on my Giro 20 going
> downhill. The back (v-brake) skidded, so I let up, I did my damndest not
> to lock the front, and didn't (riding a motorcycle has some advantages)
> but the thing showed no sign of an endo I could feel.
>
Since this is a Giro 20, it should be noted that the front wheel size is
ISO 406-mm, which is relevant, since the effectiveness of a disc (or
drum) brake increases with decreasing wheel diameter.

> Indeed, trying same when I first got the disks didn't get me anywhere.
> Locking the front is hard to do when you have trained for years not
> to, so maybe I wasn't trying hard enough. Never felt a massive weight
> transfer forward, nothing like pulling a stoppie on a motorcycle (which
> I have done more than once).
>
See other posts about the rider's legs providing bracing against the
rider moving forward.

> If they will "endo easily" then I must be dreaming...
>
> So I have to ask... have you ridden one? Have you managed to endo it?
>
The anti-recumbent "experts" don't need no steenkin' test rides!

> If so, how? What did it feel like, when did the weight transfer get so
> over rather than forward (hard transfer on a bent feels qualitatively
> different to hard transfer on an upright to me), and how fast did you have
> to go, and how fast were you going when you managed to get it to go over?
>
Back in the early days of the 20th Century recumbent revival (e.g.
Hypercycle, the never produced Avatar 1000,) the designers mistakenly
thought that some heel/wheel overlap needed to be avoided. Therefore,
the boom was made very long and the rider was seated almost over the
front wheel. This led to too flexible booms which made climbing and
acceleration poor, poor handling - especially when hitting bumps at
speed , and the bike rotating forward about the front wheel contact
patch under hard braking.

Modern short=wheelbase recumbent sensibly trade off some heel overlap
for proper weight distribution and have none of the above flaws.
However, some of the "experts" tried the earlier designs 25 or 30 years
ago and have closed their minds to later improvements.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful

 

[Tom Sherman]

Edward Dolan wrote:
> "Tom Sherman" <[email protected]> wrote in message
> news:[email protected]...
> [...]
>> Back in the early days of the 20th Century recumbent revival (e.g.
>> Hypercycle, the never produced Avatar 1000,) the designers mistakenly
>> thought that some heel/wheel overlap needed to be avoided. Therefore, the
>> boom was made very long and the rider was seated almost over the front
>> wheel. This led to too flexible booms which made climbing and acceleration
>> poor, poor handling - especially when hitting bumps at speed , and the
>> bike rotating forward about the front wheel contact patch under hard
>> braking.
>>
>> Modern short=wheelbase recumbent sensibly trade off some heel overlap for
>> proper weight distribution and have none of the above flaws. However, some
>> of the "experts" tried the earlier designs 25 or 30 years ago and have
>> closed their minds to later improvements.
>
> Even so, SWB recumbents do not handle well and tend to be squirrely. They
> are fine for around town for a few hours, but they are the pits on day long
> rides.

My short-wheelbase recumbents (RANS Rocket, Earth Cycles Sunset
Lowracer) are easy to ride, even after I have hammered to the point of
exhaustion on a double metric century.

> Also, heel overlap is not a good idea. Sooner or later it will trip
> you up.
>
Not a big deal as long as there is nothing for the crank to hit. Crank
to wheel overlap can dump you in a hurry. Of course, that can only
happen at low speed, and a low speed fall on a recumbent is trivial
compared to doing the same on an upright.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful