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On 22 Mar 2005 04:23:06 -0800, "dkahn400"
wrote:

Martin Wilson wrote:

Its well documented that the GT triple triangle frame design is
more rigid because it supports the seat stays at both the seat
tube and top tube with welds. As a heavier rider I'm obviously
going to get more movement there.

Really? Where is it so documented? This is the design that Sheldon
Brown has described in the following terms.

: This is not sturdier, it is a bogus design used for cosmetic
: purposes, to build brand differentiaton. It is based on
: marketing, not engineering. It makes the bike heavier, but has
: no functional value.

And from Sheldon's glossary (under Hellenic):

: It is of no practical value, and often causes un-necessary
: complication to brake cable routing, luggage rack attachment
: and installation of frame pumps. It is also slightly heavier
: than normal frame construction.

So your basically saying sheldon brown doesn't like them so the extra
welded length of stays to the top tube has absolutely no improvement
in strength at all. The fact the seat stays have two welded/anchor
points does not add any strength what so ever. Admittedly the well
documented statement is referring to mainly GT's own information but
real world users seem to accept GTs on this level and they have an
excellent reputation for strength. After reading various postings
about the unbreakable quality of GT's old triple triangle chromoly and
unbutted frames I picked up a GT Timberline FS on ebay to muck about
with offroad. The story goes that GT famous for bmx produced early
generations of mountain bikes with well over the top strength. There
are a few stories of near total abuse and still surviving.

It seems everything is open to debate on this forum. I'm not sure I
even care anyway but I've read lots of postings where the GT triple
triangle was discussed as having a harsher ride and as this would link
to GT's own statement regarding strength and more rigidity I perhaps
unfairly took it to be true.

Anyway my original point still stands the high tensile frame is more
comfortable and seems to have more flexing and seems to soften the
impact of potholes etc. I had in mind that the oversized main tube
created a more rigid main triangle and the chain and seat stays were
forced more to flex because of it. The reason I have discounted the
saddle from the equation is because often when I see bumps I obviously
lift off the saddle to go over them and even then there seems to be a
reduction in the impact as the rear wheel goes over it.

Where are the hordes of people who buy these cheap bikes?
Shouldn't we be seeing a massive increase of cyclists on the roads?

Ah well, shouldn't feed the Trolls.

Cheers
Dave R


This is what I don't get and perhaps it a local thing but where I live
the vast majority of bikes ridden are low cost bikes. Maybe for every
20 bikes I see one will be a fairly new well regarded brand. The other
19 will be low cost bikes are very old bikes like Raleighs. The only
Kona or Giant I've seen on the road are my own. Close enough to make
out the brand that is as I've perhaps seem them from a distance and
not been able to make out the brand. Then again if I think about whose
actually riding bikes the vast majority are teenagers or younger.

If I was guessing where these bikes are bought from I would say
Halfords, supermarkets and mail order catalogues.

Then again where I live we never have much in the way of traffic jams
or car commuting problems.

Assuming that people in this forum are correct and the vast majority
of cheap bikes aren't ridden then here that would probably equate to
about 200 cheap bikes sold for every 1 high quality brand.

On Mon, 21 Mar 2005 23:51:36 +0000, Jon Senior
jon_AT_restlesslemon_DOT_co_DOT_uk wrote:

Martin Wilson wrote:

So lets get this straight. They have a large collection of high
tensile steel frames that have broken in use either the welds or
tubeing. What is their motivation to keep these frames?

Because we recycle stuff. Those bikes that can be made usable are, and
those that can't are collected, sorted by material and sold as scrap.

It doesn't surprise me about tourney gears. They are ok and workable
but the shimano models higher up in the range have a crisper and
faster gear change. While tourney gears are widely used on sub £100
bikes they also feature on higher end models upto £400.

I find that disturbing. They are somewhat shaky and when I was budgeting
around £400 for a new bike (Ended up revising upwards somewhat!) I was
looking at Sora or Sora / Tiagra mix.


Last time I googled a womans hybrid came up at £400 with a shimano
tourney rear derailleur but can't see it now. There are a few bikes at
£400 with tourney front derailleurs. The annoying thing is that if
they fit a tourney to a higher priced bike they often won't mention it
by name for obvious reasons. They just say shimano gearing etc. Anyway
here's a £300 bike with tourney style steel pressed type derailleur

Its the silverfox knarly

http://www.grattan.co.uk/Web/images/...rge/89W574.jpg

I'm sure there are dearer bikes with them fitted it just takes more
than a casual search to find them. However there are masses of bikes
at around £200-250 with rear tourney derailleurs. The point is these
are identical derailleurs to those fitted to the £40 sterlinghouse
bikes etc. You don't like them and I don't like them but a massive
amount of people are using them. Raleigh seem to fit them to almost
every bike they do. I think halfords wanted £15.99 for a tourney rear
derailleur when I overheard a conversation from a customer needing a
new rear derailleur when some kids had stepped all over his kids bike
breaking it. Not sure if this included fitting. It was the only option
he was given I think probably because of no gear hanger on the bike.
Makes you wonder how a £40 bike can have a rear derailleur that sells
for £15.99.




I think I've already answered that elsewhere.

Sorry. I'll read through the rest of the posts and find out your
justification.

Jon

On Sun, 20 Mar 2005 20:05:19 -0000, "Clive George"
wrote:

"Martin Wilson" wrote in message
.. .

I've never seen a cheap bike with terrible alignment or substandard
components.

You've described the tourney rear mech (common on cheap bikes) as
substandard...

clive


I see substandard and workable but not brilliant as different. The
tourney is usable, its slow to change and for this reason not ideal.
the spring is a bit lightweight. Its not unsafe. Its low performance.
I see substandard as unsafe and unusable which is different. I'm
certainly in 100% agreement though that the higher end shimano's are
better. Crisper gear change and faster.

On Tue, 22 Mar 2005 18:40:55 +0000, Martin Wilson
wrote in message
:

So your basically saying sheldon brown doesn't like them so the extra
welded length of stays to the top tube has absolutely no improvement
in strength at all.

Seems fair. Sheldon is a guru, after all.


Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken

On Tue, 22 Mar 2005, Martin Wilson wrote:

So your basically saying sheldon brown doesn't like them so the extra
welded length of stays to the top tube has absolutely no improvement
in strength at all. The fact the seat stays have two welded/anchor
points does not add any strength what so ever.

Absolutely. In fact, by adding local bending top teh tubes by loading
them other than at teh node points of the truss, if anything, you'll
weaken teh frame. They've taken a nice tidy shape that is
intrinsically rigid without introducing local bending in teh elements
of teh frame, then converted it to something that relies on local
bending.

real world users seem to accept GTs on this level and they have an
excellent reputation for strength. After reading various postings

So they make teh tubes thicker to compensate for poor design - doesn't
make teh design good, and especially doesn't make it efficient.

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

On Tue, 22 Mar 2005 19:39:50 +0000, Martin Wilson
wrote in message
:

silverfox knarly

I did a quick Google on that. Sterling house sell it (always a bad
sign) at £225, much less than the price you stated. A full-sus bike
for £225? I'd expect it to be pretty poor. A decent rear shock costs
twice that, I know because I can't afford to upgrade my cheap Ballista
to a decent airshock.

Lots of other generic mail order shops seem to sell the same model.
But it's not on places like Bonthrone Bikes. My local MTB specialists
don't stock that brand at all (they do Trek, Marin, Gary Fisher,
Whyte, Rocky Mountain and Cove). My LBS stocks the following brands
(takes deep breath): Bianchi, Cervelo, Colnago, Dahon, Dawes, De Rosa,
Electra, Fit, Fuji, Gary Fisher, Giant, Hoffman, Isaac, Kestrel,
Klein, Kona, Lemond, Litespeed, Mezzo, Mongoose, Mountain Cycle,
Orbea, Pashley, Perv(!), Pinarello, Principia, Quintana Roo,
Ridgeback, Saracen, Tifosi, Trek, Vario and Viking.

Of these I know that Dawes, Trek, Gary Fisher and Saracen all do
competent bikes at the £200 mark, and that's at bike shop prices.
£200 should get you a reasonable rigid MTB-style bike. With luck you
might even get front sus for that, although it might not be very good.
The bike you saw? That's being offered by Sterling House for the same
price as a Dawes Tekarra with front sus in my LBS. I would have the
Dawes.

http://www.awcycles.co.uk/products.p...d=m1b47s2p3632

You can get a full-sus bike from my LBS for that sort of cash:
http://www.awcycles.co.uk/products.php?plid=m1b8s1p3127 but I don't
really fancy it.

Most of the cheap bikes seem to have (Tourney) TX50 rear mechs. These
are *not* the same as the old "Shimano SIS" crap seen on early low-end
indexed bikes. We have bikes with both sorts; the Tourney style have
in my experience two main faults: one, they have plastic adjuster
barrels, which tend to strip, and two, the cages bend rather easily.
Apart from that they are functional.

Actually I have SIS, Tourney, Acera, Deore, Deore LX and Deore XT. Of
these the only one which is actually crap is the SIS. Oh, and I had
some trouble with the Deore but that was 9-speed job and on the
recumbent with very long cable runs. After I'd replaced it I found
that the real problem was simply that the hanger was too thick - I
ground 1/16" off it and it's fine now, so I think even base spec Deore
probably works OK.

My experience with Tourney is that if they (and the chain) are kept
well lubricated they work as well as anything else, but they are
intolerant of abuse, especially mechanical abuse. On the plus side,
the cages are made of cheese so straightening them out is a job for
fingers not the vice.

The most dependable bike in our house is my wife's 2001 Dawes
Saratoga, Tourney rear mech, Cr-Mo frame. I put Alesa XPlorer rims
and a Deore XT rear-end on because the trailer bike was taking its
toll. Cassette rear end - there's a must for the heavier rider.
Avoid screw-on blocks! That's the same price now in aluminium with
front sus as it was then in Cr-Mo with a rigid fork. Incredible,
really.


Guy
--
http://www.chapmancentral.co.uk

"To every complex problem there is a solution which is
simple, neat and wrong" - HL Mencken

Martin Wilson wrote:
[snip several paragraphs about cheap bike frames, one of several posts
in this thread on the same subject by Martin, and it's not the first
thread where he's engaged on the subject]...
I'm not sure I
even care anyway
....[snip another couple of paragraphs]

I can hardly wait to see what you'll do for a topic you really care about.

--
Joe * If I cannot be free I'll be cheap

JLB wrote:

Martin Wilson wrote:
[snip several paragraphs about cheap bike frames, one of several posts
in this thread on the same subject by Martin, and it's not the first
thread where he's engaged on the subject]...

I'm not sure I
even care anyway

...[snip another couple of paragraphs]

I can hardly wait to see what you'll do for a topic you really care about.


Do you think he might...gulp....contribute to the FAQ?

Naaaah, too much bother.

James

in message , Martin Wilson
') wrote:

On 22 Mar 2005 04:23:06 -0800, "dkahn400"
wrote:

Martin Wilson wrote:

Its well documented that the GT triple triangle frame design is
more rigid because it supports the seat stays at both the seat
tube and top tube with welds. As a heavier rider I'm obviously
going to get more movement there.

Really? Where is it so documented? This is the design that Sheldon
Brown has described in the following terms.

: This is not sturdier, it is a bogus design used for cosmetic
: purposes, to build brand differentiaton. It is based on
: marketing, not engineering. It makes the bike heavier, but has
: no functional value.

And from Sheldon's glossary (under Hellenic):

: It is of no practical value, and often causes un-necessary
: complication to brake cable routing, luggage rack attachment
: and installation of frame pumps. It is also slightly heavier
: than normal frame construction.

So your basically saying sheldon brown doesn't like them so the extra
welded length of stays to the top tube has absolutely no improvement
in strength at all.

Martin, I am _not_ deliberately having a go at you. But it doesn't seem
likely. The conventional diamond frame geometry makes each element
either a relatively pure compression element (the seat stay, seat tube,
top tube) or a pure tension element (the chain stay, down tube).

Bonding the seat stay to the seat tube at 75% of its length and to the
top tube at about 70% of it length means you are inducing bending loads
in both the seat tube and the top tube, and thin-wall tubes are not
particularly good at resisting bending. Also, the tubes need to be
thickened around the joins so that the heat effects of welding don't
unduly weaken the tube. So at a first analysis I would expect it to be
weaker, heavier and/or less rigid.

It seems everything is open to debate on this forum. I'm not sure I
even care anyway but I've read lots of postings where the GT triple
triangle was discussed as having a harsher ride and as this would link
to GT's own statement regarding strength and more rigidity I perhaps
unfairly took it to be true.

The harsher ride might simply be the thicker tubes needed to stand up to
the extra welds.

--
(Simon Brooke) http://www.jasmine.org.uk/~simon/
Das Internet is nicht fuer gefingerclicken und giffengrabben... Ist
nicht fuer gewerken bei das dumpkopfen. Das mausklicken sichtseeren
keepen das bandwit-spewin hans in das pockets muss; relaxen und
watchen das cursorblinken. -- quoted from the jargon file