Side loads on wheels

Ryan Cousineau said:

This is not meant as a dis' on you, Chalo, but your ability to make a component fail does not make
me believe that said component is underdesigned for most riders. You are not most riders, and
must, alas, choose your equipment accordingly.

My point was not to suggest that wheels are underdesigned, but rather that normal (or at least
reasonably foreseeable) riding conditions can generate significant out-of-plane wheel loads.

I am certain that I still develop the same magnitude of side loading on my wheels occasionally, but
now they are built plenty strong to cope with the conditions.

Chalo Colina

An interesting thread. Most of the argument seems to revolve around at what level side loads become
a problem, so here is a useful data point: tricycles generate side loads with every turn and with
every non-level surface. A free body diagram will readily show that the lower the combined cener of
mass, the greater the side loads at the limit, which is the tipover point.

My experience with recumbent trikes is that cornering speeds which lift the inside wheel do not
result in any rim deformation or spoke loosening or breakage even if done with regularity,
indicating that side loads of up to 300 pounds are well tolerated by wheels of normal construction.
However these wheels are 20" diameter, obviously much stronger to side loads than a 700c wheel when
both use the same flange spacing.

--
Ted Bennett Portland OR

"dianne_1234" <[email hidden]> wrote in message
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Quoted message said:

Could these test results be used to approximate the contribution of the fork in Kraig's set up?

sheldonbrown.comrinard forktest.htmlOpen ↗

IMHO, no - that loading condition is only a part of how forks are loaded during out of the
saddle riding.

What would be good info to have would be the actual EI data for forks (at least every inch or so
along the length) so that fork leg curvature and its effects on wheel deflection could be better
quantified.

This type of data is more difficult to come by than slapping a $10 dial indicator and some band
clamps on my bike.

--
==================
Kraig Willett www.biketechreview.com
==================

Kraig Willett said:

Quoted message said:

Could these test results be used to approximate the contribution of the fork in Kraig's set up?

Quoted message said:

Quoted message said:

sheldonbrown.comrinard forktest.htmlOpen ↗

Quoted message said:

IMHO, no - that loading condition is only a part of how forks are loaded during out of the
saddle riding.

Quoted message said:

What would be good info to have would be the actual EI data for forks (at least every inch or so
along the length) so that fork leg curvature and its effects on wheel deflection could be better
quantified.

That isn't interesting for the question at hand, that of wheel deflection and its ability to take
such loads. By making it so all encompassing you make it so difficult that it won't be done at all,
leaving us with a dangling question.

Quoted message said:

This type of data is more difficult to come by than slapping a $10 dial indicator and some band
clamps on my bike.

Let's just isolate the variables. Determine the deflection as measured at the fork crown for the
same side loads on the tire and on the axle. This would enable separating fork flex from
fork-wheel flex.

Jobst Brandt [email hidden] Palo Alto CA

<[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Kraig Willett said:

What would be good info to have would be the actual EI data for forks (at least every inch or so
along the length) so that fork leg curvature and its effects on wheel deflection could be better
quantified.

That isn't interesting for the question at hand, that of wheel deflection and its ability to take
such loads. By making it so all encompassing you make it so difficult that it won't be done at
all, leaving us with a dangling question.

Fair enough. However, you were the one that suggested the experimental determination of the fork
effect. I am simply suggesting a more rigorous method of doing the task that you suggest.

From what I have seen and read, no one has actually gone to the trouble of actually doing what I did
on my apartment floor a couple of years ago for a completely separate purpose than what is being
discussed in this thread. I am trying to utilize this data for the purposes of this thread. I have
made the data and methods available for critique - have at it!

You have still not commented on the methodology I employed/ assumptions I made when trying to
estimate dynamic side loads based on measured static and dynamic deflections. Until that is
addressed we really can't progress any further. I am unconvinced that all of the deflection I
observed is from a pure side load - are you convinced that it is?

Quoted message said:

Quoted message said:

This type of data is more difficult to come by than slapping a $10 dial indicator and some band
clamps on my bike.

Let's just isolate the variables. Determine the deflection as measured at the fork crown for the
same side loads on the tire and on the axle. This would enable separating fork flex from
fork-wheel flex.

Address the potentially poor assumptions I used in my experiment, then we can move forward with
separation of the variables to determine relative contributions. I executed a protocol, which to me,
seems reasonable (admittedly with poor instrumentation) for determining dynamic side loads.

Point out the deficiencies in my process, methods, instrumentation.

For me, the contribution of this particular fork doesn't really matter since it was held constant
for the several different wheels tested. The magnitude of the flexible boundary condition was
interesting to me having a large amount of experience testing wheels in a similar manner as Damon
Rinard (fixed boundary condition).

IMHO, fixity-ness plays a huge role in wheel deflection - just as it does in the beam equations.

As far as lateral wheel strength goes, you have addressed this already. Your experience (from what I
selectively remember reading) is similar to my lab and field test experience.

--
==================
Kraig Willett www.biketechreview.com
==================

Quoted message said:

Quoted message said:

This type of data is more difficult to come by than slapping a $10 dial indicator and some band
clamps on my bike.

Let's just isolate the variables. Determine the deflection as measured at the fork crown for the
same side loads on the tire and on the axle. This would enable separating fork flex from
fork-wheel flex.

Jobst Brandt

Somewhere or another, it seems that we've migrated off the mtn/suspension fork + wheel side loads
to road forks/wheels. Since mtn forks have sliding legs, they're going to move around more than a
road fork.

I know that on my road bike, even with a radial front wheel, there's some movement, but not enough
to rub the brakes. On my mtn bikes with suspension forks, it happens a lot more often. My Mag21 was
notorious for this. Get a little grit between the brake pads and the rim and its pretty obvious that
its happening.

So, which suspension fork is the stiffest? Since I'm in the market for a new one, its a
pertinent question.

Mike

In article tXwIa.160779$eJ2.75797@fed1read07 said:

So, which suspension fork is the stiffest? Since I'm in the market for a new one, its a pertinent
question.

Cannondale Headshok. IMHO it's far and away the best MTB suspension fork design.

Chalo:

Quoted message said:

My point was not to suggest that wheels are underdesigned, but rather that normal (or at least
reasonably foreseeable) riding conditions can generate significant out-of-plane wheel loads.

I am certain that I still develop the same magnitude of side loading on my wheels occasionally,
but now they are built plenty strong to cope with the conditions.

The one time I borrowed a flimsy pair of wheels I was not able to corner at normal speed because of
a whip effect I can only put down to side-loads on the wheels.

The "balancing act" argument seems to have the unicycle covered but with two wheels and the riders
mass in between there should be scope for "wiggle" effects like you describe.

Andrew Bradley

"Tim McNamara" <[email hidden]> wrote in message
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Quoted message said:

In article <tXwIa.160779$eJ2.75797@fed1read07>,

Quoted message said:

Mike S.' mikeshaw2@coxDOTnet said:

So, which suspension fork is the stiffest? Since I'm in the market for a new one, its a
pertinent question.

Cannondale Headshok. IMHO it's far and away the best MTB suspension fork design.

They're great, but only come with Cannondales.

For a standard, retrofittable, telescopic shock, Fox are probably the stiffest -- and the best --
and the most expensive.

Matt O.

In article <[email hidden]>, "Matt O'Toole"

Quoted message said:

"Tim McNamara" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

In article <tXwIa.160779$eJ2.75797@fed1read07>,

Quoted message said:

Mike S.' mikeshaw2@coxDOTnet said:

So, which suspension fork is the stiffest? Since I'm in the market for a new one, its a
pertinent question.

Cannondale Headshok. IMHO it's far and away the best MTB suspension fork design.

They're great, but only come with Cannondales.

Merlin also makes a headshock bike, having licensed the design from Cannondale. Cha-chinnnggg!