Boardman bikes

[Tony Raven]

Rob wrote:
>
> My employer had a cycle to work scheme - the catch being that you had to
> get the bike through Halfords. Which pretty much ruled it out for me.
> The Boardman bikes might make me look again when/if it's relaunched.
>

Halfords will get other bikes than those in stock and often arrange them
through a distributor of the model you want. For example I got my
Brompton under the Halfrauds scheme but picked it up from Bikefix.
Halfrauds in this case just handled the finances, not the bike.

Tony

 

[Tony Raven]

Membrane wrote:

>
> But I don't know if the top tube in a bicycle frame needs to be
> preferentially strong in a certain plane. I suspect not, in which case
> my guess is that for a square tube and a round tube of equal weight,
> round is the better shape.
>


The ideal is laterally stiff but vertically compliant.

Tony

 

[Peter Clinch]

Tony Raven wrote:

> Only in what the employer pays. When I got my bike under the scheme I
> paid the balance over £1k direct to the shop. I didn't get the tax
> break on the extra but I got the bike I wanted.

This is employer/scheme setup dependent. It very specifically is *not*
allowed here, for example.

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/

 

[Alistair Gunn]

Membrane twisted the electrons to say:
> Isn't there a £1000 spending limit under the bike2work scheme? If so
> then afaics only the entry level Boardman road bike would quality.

Actually, it's only the top level Boardman road bike that doesn't qualify
(as it costs #1399.99). The lower two models cost #899.99 and #599.99,
and so would be available on the basic bike2work scheme.

The middle model is actually kind of tempting, but I suspect only because
I've been paying a little too much attention to Le Tour on ITV ...
--
These opinions might not even be mine ...
Let alone connected with my employer ...

 

[Zog The Undeniable]

Membrane wrote:
> Had a gander at the Boardman road bikes at a local Halfords at the
> weekend (was in there to get some copper grease). 3 models, one 105, one
> Ultegra and the top model Dura Ace based. The top model out of those
> three was mixed with a Truvativ carbon crank set. An eerie feeling crept
> over me seeing Ultegra and Dura Ace parts on bikes sold by Halfords,
> something felt wrong with that. Who would buy a mid to high end bike
> from Halfords?
>
> Their square top tubes also looked really strange, afaik round tubing is
> the strongest shape, it looked like a fashion gimmick. All three had alu
> alloy frames, top model had carbon seat stays + carbon horizontal tubes
> in the rear triangle.
>
> Finishing detail on the bikes looked poor, but that could have been down
> to this particular Halfords branch (I've seen bikes on display half
> coming apart in their racks before), or Joe public not being able to
> resist lifting these bikes up to see how much they weigh (myself
> included :-/ ).
>
I hate the colour scheme, and what did/does Boardman know about MTBs?
He disliked cycling anyway - he just did it for a living.

 

[pasty]

On Jul 24, 5:50 pm, Zog The Undeniable <[email protected]> wrote:
> Membrane wrote:
> > Had a gander at the Boardman road bikes at a local Halfords at the
> > weekend (was in there to get some copper grease). 3 models, one 105, one
> > Ultegra and the top model Dura Ace based. The top model out of those
> > three was mixed with a Truvativ carbon crank set. An eerie feeling crept
> > over me seeing Ultegra and Dura Ace parts on bikes sold by Halfords,
> > something felt wrong with that. Who would buy a mid to high end bike
> > from Halfords?
>
> > Their square top tubes also looked really strange, afaik round tubing is
> > the strongest shape, it looked like a fashion gimmick. All three had alu
> > alloy frames, top model had carbon seat stays + carbon horizontal tubes
> > in the rear triangle.
>
> > Finishing detail on the bikes looked poor, but that could have been down
> > to this particular Halfords branch (I've seen bikes on display half
> > coming apart in their racks before), or Joe public not being able to
> > resist lifting these bikes up to see how much they weigh (myself
> > included :-/ ).
>
> I hate the colour scheme, and what did/does Boardman know about MTBs?
> He disliked cycling anyway - he just did it for a living.- Hide quoted text -
>
> - Show quoted text -

he got some as yet unnamed mountain biker to design them.

 

[Rob Morley]

In article <[email protected]>, Membrane
[email protected]lid says...
> Rob Morley <[email protected]> wrote:
>
> >> Their square top tubes also looked really strange, afaik round tubing is
> >> the strongest shape, it looked like a fashion gimmick.
> >
> >From an engineering POV funny tube shapes and sizes are usually about
> >stiffness-to-weight ratio rather than strength-to-weight ratio. Carbon
> >fibre allows a lot of fine tuning in the layup - it's quite possible
> >that the sides of the square tube have more layers of carbon fibre than
> >the top and bottom, giving greater side-to-side stiffness combined with
> >a bit more spring vertically. Or it could just be a marketing gimmick.
> >
>
> Top tubes on Boardman road bikes are alu alloy.
>
>
I should have been paying more attention, but the same applies to alloy
as to plastic - varied wall thickness around the tube results in
different ride characteristics, and that's more easily done with a
square section tube.

 

[Ben C]

On 2007-07-25, Rob Morley <[email protected]> wrote:
> In article <[email protected]>, Membrane
> [email protected]lid says...
>> Rob Morley <[email protected]> wrote:
>>
>> >> Their square top tubes also looked really strange, afaik round tubing is
>> >> the strongest shape, it looked like a fashion gimmick.
>> >
>> >From an engineering POV funny tube shapes and sizes are usually about
>> >stiffness-to-weight ratio rather than strength-to-weight ratio. Carbon
>> >fibre allows a lot of fine tuning in the layup - it's quite possible
>> >that the sides of the square tube have more layers of carbon fibre than
>> >the top and bottom, giving greater side-to-side stiffness combined with
>> >a bit more spring vertically. Or it could just be a marketing gimmick.
>> >
>>
>> Top tubes on Boardman road bikes are alu alloy.
>>
>>
> I should have been paying more attention, but the same applies to alloy
> as to plastic - varied wall thickness around the tube results in
> different ride characteristics, and that's more easily done with a
> square section tube.

Why?

 

[Rob Morley]

In article <[email protected]>, Ben C
[email protected] says...
> On 2007-07-25, Rob Morley <[email protected]> wrote:

> > I should have been paying more attention, but the same applies to alloy
> > as to plastic - varied wall thickness around the tube results in
> > different ride characteristics, and that's more easily done with a
> > square section tube.
>
> Why?
>
Why what?

 

[Peter Clinch]

Rob Morley wrote:
> In article <[email protected]>, Ben C
> [email protected] says...
>> On 2007-07-25, Rob Morley <[email protected]> wrote:
>
>>> I should have been paying more attention, but the same applies to alloy
>>> as to plastic - varied wall thickness around the tube results in
>>> different ride characteristics, and that's more easily done with a
>>> square section tube.
>> Why?
>>
> Why what?

I'd guess he meant "why is it easier to vary tube thickness in a square
section than a round one?"

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/

 

[Membrane]

Rob Morley <[email protected]> wrote:

>varied wall thickness around the tube results in
>different ride characteristics

I remain sceptical about that notion. Up until now I had only considered
push, pull, vertical, or side to side forces on the top tube, but I now
think that in practice the only stresses exerted on the top tube in the
main triangle on a bicycle frame that affect ride characteristics are
torsion forces. Afaics the push-pull flex can be considered non existent
for practical purposes, and vertical and side to side forces are non
existent whilst riding.

I have no real knowledge of mechanical engineering, but my guess is that
when comparing square tubing to round tubing (of the same weight), round
tubing is the ideal shape, i.e. stiffer with regard to torsion when
compared to square tubing.

Afaics the only torsion-strenght affect different wall thickness on
square tubing would have is to weaken the tube further when compared to
same wall thickness square tubing.

--
Membrane

 

[Ben C]

On 2007-07-25, Peter Clinch <[email protected]> wrote:
> Rob Morley wrote:
>> In article <[email protected]>, Ben C
>> [email protected] says...
>>> On 2007-07-25, Rob Morley <[email protected]> wrote:
>>
>>>> I should have been paying more attention, but the same applies to alloy
>>>> as to plastic - varied wall thickness around the tube results in
>>>> different ride characteristics, and that's more easily done with a
>>>> square section tube.
>>> Why?
>>>
>> Why what?
>
> I'd guess he meant "why is it easier to vary tube thickness in a square
> section than a round one?"

Yes, that is what I meant.

 

[Tony B]

Membrane wrote:
> I now think that in practice the only stresses exerted on the top tube in the
> main triangle on a bicycle frame that affect ride characteristics are
> torsion forces.

> I have no real knowledge of mechanical engineering,

er, quite - however, I think it is safe to say that bike top tubes
(indeed, all the tubes) are subject to a variety of loads from various
directions that stress them in rather complicated ways. Whether or not
these loads are best handled by square or round (or even round that
become square) tubes is prolly a moot point, "best" being a bit
subjective. I guess for a racing bike we are talking best=light? But it
has to be stiff enough to handle the loads. No-one wants to ride a bendy
bike (except maybe me on long audaxes . For racing bikes, best=first!

The biggest driver (after various UCI rules of course) is most certainly
the bling factor. If it looks right it will sell, and bicycle companies
exist to make £££.

If ICBA I may go away and have a look in "Bicycling Science" ce soir to
see if there are any clues in there about frame loading. Then again, I
may just hit the couch with a Kronenbourg and today's TdF highlights

Tony B

 

[Ian Smith]

On Wed, 25 Jul, Peter Clinch <[email protected]> wrote:
> Rob Morley wrote:
> > In article <[email protected]>, Ben C
> > [email protected] says...
> >> On 2007-07-25, Rob Morley <[email protected]> wrote:
> >
> >>> I should have been paying more attention, but the same applies to alloy
> >>> as to plastic - varied wall thickness around the tube results in
> >>> different ride characteristics, and that's more easily done with a
> >>> square section tube.
> >> Why?
> >>
> > Why what?
>
> I'd guess he meant "why is it easier to vary tube thickness in a square
> section than a round one?"

Well, Pace used to (maybe still) do it by machining out parts of the
wall thickness. That is much easier on properly square tube than any
rounded shape, because you can do it with a milling machine moving one
axis at a time, rather than needing a CAM machine tracking funny
profiles in 3D space.

If you're drawing the tube, I can't see why it would be easier with
square than round, but it would probably be easier to assemble the
tubes - if your tubes were externally circular, you'd need some
special measures to make sure they are oriented correctly. If they
only fit in the assembly jig the right way round, that's easier.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

 

[Rob Morley]

In article <[email protected]>, Ian Smith
[email protected] says...
> On Wed, 25 Jul, Peter Clinch <[email protected]> wrote:
> > Rob Morley wrote:
> > > In article <[email protected]>, Ben C
> > > [email protected] says...
> > >> On 2007-07-25, Rob Morley <[email protected]> wrote:
> > >
> > >>> I should have been paying more attention, but the same applies to alloy
> > >>> as to plastic - varied wall thickness around the tube results in
> > >>> different ride characteristics, and that's more easily done with a
> > >>> square section tube.
> > >> Why?
> > >>
> > > Why what?
> >
> > I'd guess he meant "why is it easier to vary tube thickness in a square
> > section than a round one?"
>
> Well, Pace used to (maybe still) do it by machining out parts of the
> wall thickness. That is much easier on properly square tube than any
> rounded shape, because you can do it with a milling machine moving one
> axis at a time, rather than needing a CAM machine tracking funny
> profiles in 3D space.
>
> If you're drawing the tube, I can't see why it would be easier with
> square than round, but it would probably be easier to assemble the
> tubes - if your tubes were externally circular, you'd need some
> special measures to make sure they are oriented correctly. If they
> only fit in the assembly jig the right way round, that's easier.
>
I couldn't have put it better myself.

 

[[email protected]]

On Jul 25, 9:10 pm, Ian Smith <[email protected]> wrote:
> On Wed, 25 Jul, Peter Clinch <[email protected]> wrote:
> > Rob Morley wrote:
> > > In article <[email protected]>, Ben C
> > > [email protected] says...
> > >> On 2007-07-25, Rob Morley <[email protected]> wrote:
>
> > >>> I should have been paying more attention, but the same applies to alloy
> > >>> as to plastic - varied wall thickness around the tube results in
> > >>> different ride characteristics, and that's more easily done with a
> > >>> square section tube.
> > >> Why?
>
> > > Why what?
>
> > I'd guess he meant "why is it easier to vary tube thickness in a square
> > section than a round one?"
>
> Well, Pace used to (maybe still) do it by machining out parts of the
> wall thickness. That is much easier on properly square tube than any
> rounded shape, because you can do it with a milling machine moving one
> axis at a time, rather than needing a CAM machine tracking funny
> profiles in 3D space.
>
> If you're drawing the tube, I can't see why it would be easier with
> square than round, but it would probably be easier to assemble the
> tubes - if your tubes were externally circular, you'd need some
> special measures to make sure they are oriented correctly. If they
> only fit in the assembly jig the right way round, that's easier.
>
> regards, Ian SMith
> --
> |\ /| no .sig
> |o o|
> |/ \|

I believe that the frame tubes' varied wall thicknesses are created by
hydraulic expansion. This is where high pressure is applied inside the
pipe to expand the inner dimension (and increase length slightly) but
maintains the outer dimension due to the tube being held in tooling
that prevents change. This only works on round extrusions, however,
with final forms, like a diamond or elliptical section requiring
rework after the tube has been hydraulically altered as above.

At least, that's how I have changed tube section thicknesses in my
engineering years.

Russtler

 

[Ian Smith]

On Thu, 26 Jul 2007, [email protected] <[email protected]> wrote:
>
> I believe that the frame tubes' varied wall thicknesses are created by
> hydraulic expansion. This is where high pressure is applied inside the
> pipe to expand the inner dimension (and increase length slightly) but
> maintains the outer dimension due to the tube being held in tooling
> that prevents change. This only works on round extrusions, however,
> with final forms, like a diamond or elliptical section requiring
> rework after the tube has been hydraulically altered as above.

As written, that sounds like bollocks to me.

Not least because it requires hydraulic fluid inserted into a circular
tube to exert greater pressure on one part of the wall than on an
adjacent section. Fluid doesn't do that.

It could possibly work to vary wall thickness along a tube, but the
situation under discussion is varying thickness around a tube. (At
least, that's how I understand it). I just can't see how the
described process can possibly achieve that.

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

 

[Lord Turkey Cough]

"bugbear" <bugbear@trim_papermule.co.uk_trim> wrote in message
news:[email protected]...
> Membrane wrote:
>> Who would buy a mid to high end bike
>> from Halfords?
>
> I think that's the key question.


Becaue neither Sainsburys nor Tesco sell them.

>
> BugBear

 

[Ben C]

On 2007-07-25, Ian Smith <[email protected]> wrote:
> On Wed, 25 Jul, Peter Clinch <[email protected]> wrote:
>> Rob Morley wrote:
>> > In article <[email protected]>, Ben C
>> > [email protected] says...
>> >> On 2007-07-25, Rob Morley <[email protected]> wrote:
>> >
>> >>> I should have been paying more attention, but the same applies to alloy
>> >>> as to plastic - varied wall thickness around the tube results in
>> >>> different ride characteristics, and that's more easily done with a
>> >>> square section tube.
>> >> Why?
>> >>
>> > Why what?
>>
>> I'd guess he meant "why is it easier to vary tube thickness in a square
>> section than a round one?"
>
> Well, Pace used to (maybe still) do it by machining out parts of the
> wall thickness. That is much easier on properly square tube than any
> rounded shape, because you can do it with a milling machine moving one
> axis at a time, rather than needing a CAM machine tracking funny
> profiles in 3D space.
>
> If you're drawing the tube, I can't see why it would be easier with
> square than round, but it would probably be easier to assemble the
> tubes - if your tubes were externally circular, you'd need some
> special measures to make sure they are oriented correctly. If they
> only fit in the assembly jig the right way round, that's easier.

Thanks for the info.

My bike actually has an oval down-tube and a quasi-triangular cross-bar
but a round seat tube. The seat tube _is_ in slightly the wrong
orientation because the bottle cage points slightly to one side.

 

[D.M. Procida]

Ian Smith <[email protected]> wrote:

> > I believe that the frame tubes' varied wall thicknesses are created by
> > hydraulic expansion. This is where high pressure is applied inside the
> > pipe to expand the inner dimension (and increase length slightly) but
> > maintains the outer dimension due to the tube being held in tooling
> > that prevents change. This only works on round extrusions, however,
> > with final forms, like a diamond or elliptical section requiring
> > rework after the tube has been hydraulically altered as above.
>
> As written, that sounds like bollocks to me.
>
> Not least because it requires hydraulic fluid inserted into a circular
> tube to exert greater pressure on one part of the wall than on an
> adjacent section. Fluid doesn't do that.
>
> It could possibly work to vary wall thickness along a tube, but the
> situation under discussion is varying thickness around a tube.

"but maintains the outer dimension due to the tube being held in tooling
that prevents change."

Daniele