Truvativ cranks? Opinions
Biot
The little I could find of old postings on this newsgroup didn't sound too
postivie. Any experiences would be appreciated.
Thanks,
Jim
S. Wood
issue; sometime in the past 3-4 months.). They said they were good as far
as aftermarket cranksets go. Truvativ does have a "splined" BB spindle that
gets around Shimano's patents, and I think they rated 3 1/2 or 4 stars. But
the bottom line was that like most aftermarket cranksets, Truvativ cannot
compare to Shimano's hollowtech technology. Shimno XT is lighter, stronger,
stiffer, and cheaper - The expensive technology needed to make these
cranksets keeps other manufacturers from doing the same.
S. Wood
"Biot" <bi...@aol.com> wrote in message
news:20001008172048...@ng-fh1.aol.com...
Jobst Brandt
> I read an article in a recent issue of Bicycling about them (Not
> sure which issue; sometime in the past 3-4 months.). They said they
> were good as far as aftermarket cranksets go. Truvativ does have a
> "splined" BB spindle that gets around Shimano's patents, and I think
> they rated 3 1/2 or 4 stars.
I would be interested in hearing what they found lacking in the design.
What was the 1/2 point loss in the rating for?
> But the bottom line was that like most aftermarket cranksets,
> Truvativ cannot compare to Shimano's hollowtech technology. Shimano
> XT is lighter, stronger, stiffer, and cheaper - The expensive
> technology needed to make these cranksets keeps other manufacturers
> from doing the same.
Well that list of comparative assessments should be accompanied by
some data. I am aware that Shimano is neither stronger nor stiffer,
that being a function of the elasticity and strength of steel, the
spindles being the same diameter. Besides, the ISIS comes in two wall
thicknesses. In fact the Shimano spline has backlash in contrast to
the ISIS. Aside from that, the Shimano spline has failed enough to be
a subject of discussion here. It seems once again that Buycycling has
taken its newsfeed from a principal advertiser.
Jobst Brandt <jbr...@hpl.hp.com>
John Red-Horse
>
>I would be interested in hearing what they found lacking in the design.
>What was the 1/2 point loss in the rating for?
>
I think that Bicycling does its ratings on a five chainring scale.
Apparently, they liked the cranks even less than you're thinking.
>
>Well that list of comparative assessments should be accompanied by
>some data. I am aware that Shimano is neither stronger nor stiffer,
>that being a function of the elasticity and strength of steel, the
>spindles being the same diameter.
But it's also a function of the geometry...
> Besides, the ISIS comes in two wall
>thicknesses.
...one example of which you note here.
>It seems once again that Buycycling has
>taken its newsfeed from a principal advertiser.
>
That certainly doesn't seem to be out of the realm of possibilities, but
wouldn't you have to support this statement with data? <g>
cheers,
john
Stephe Thayer
"Jobst Brandt" <jbr...@hpl.hp.com>
> Aside from that, the Shimano spline has failed enough to be
> a subject of discussion here.
Well the failure of the old square spindle has had MUCH more discussion here
than the shimano spline has. We know that -you- don't like the design but in
practice, the people I've talked to that works on hundreds of bikes a week,
haven't seen the failure rate you imply is the norm. Quoting you "Well that
list of comparative assessments should be accompanied by some data." Lets
see the numbers Jobst if these cranks have such a high failure rate as you
imply.
That's what I thought.
--
Stephe
Mike Wright
wrote:
>I read an article in a recent issue of Bicycling about them (Not sure which
>issue; sometime in the past 3-4 months.). They said they were good as far
>as aftermarket cranksets go. Truvativ does have a "splined" BB spindle that
>gets around Shimano's patents, and I think they rated 3 1/2 or 4 stars. But
>the bottom line was that like most aftermarket cranksets, Truvativ cannot
>compare to Shimano's hollowtech technology. Shimno XT is lighter, stronger,
>stiffer, and cheaper - The expensive technology needed to make these
>cranksets keeps other manufacturers from doing the same.
>
>S. Wood
>
>"Biot" <bi...@aol.com> wrote in message
>news:20001008172048...@ng-fh1.aol.com...
>> Mountain Bike Action magazine mentioned Truvativ cranks as a popular add
>on?
>> The little I could find of old postings on this newsgroup didn't sound too
>> postivie. Any experiences would be appreciated.
>>
>> Thanks,
>> Jim
>
>
I have a Truvativ (I think it is Firex?) for square bb, paid like $89,
like it a lot. Cheap and good, a good value.
ttur...@my-deja.com
Hard tail. So far I have had no complaints on them. I do have some not
so crisp shifting from the middle chainring down to the granny gear. I
put most of the blame on my XT Mega 9 FD. The cranks work fine for me
(180lbs), and have been worth it to me. I've heard that the splined BB
and Crank combination is pretty bomb proof as well. I've yet to try
them myself though. Hope this helps.
RUBEN
Sent via Deja.com http://www.deja.com/
Before you buy.
mchou
money. No complaints. About the only disappointmont was the 170mm
cranks I got (via mail order) was obviously a 175mm crank with the
pedal eye drilled 5mm closer to center of crank. Truvativ obviously
cut a corner and saved some tooling costs.
Cheers,
Mark
In article <20001008172048...@ng-fh1.aol.com>,
bi...@aol.com (Biot) wrote:
> Mountain Bike Action magazine mentioned Truvativ cranks as a popular
add on?
> The little I could find of old postings on this newsgroup didn't
sound too
> postivie. Any experiences would be appreciated.
>
> Thanks,
> Jim
>
Helmut Springer
> spindles being the same diameter. Besides, the ISIS comes in two
> wall thicknesses. In fact the Shimano spline has backlash in
> contrast to the ISIS. Aside from that, the Shimano spline has
is there some URL for a spec of ISIS?
TIA,
--
MfG/best regards, helmut springer
de...@FaVeVe.Uni-Stuttgart.DE
"Freedom's just another word for nothing left to lose"
James Thomson
> is there some URL for a spec of ISIS?
James Thomson
A Muzi
all that excited about these cranks, but there's nothing wrong with the
way they do this.
mchou wrote:
--
Yellow Jersey, Ltd
http://www.yellowjersey.org
http://www.execpc.com/yellowje
Open every day since 1 April, 1971
Todd Kuzma
> Well the failure of the old square spindle has had MUCH more discussion here
> than the shimano spline has. We know that -you- don't like the design but in
> practice, the people I've talked to that works on hundreds of bikes a week,
> haven't seen the failure rate you imply is the norm. Quoting you "Well that
> list of comparative assessments should be accompanied by some data." Lets
> see the numbers Jobst if these cranks have such a high failure rate as you
> imply.
Your figures are anecdotal as well. Frankly, it would be hard to get good
figures or even good anecdotes as there are very few splined BBs in use
compared to the square taper design. If your friends that work on "hundreds of
bikes a week" (apparently only averaging a few minutes per bike - must be fast
mechanics) would probably wait a several weeks before working on one bike with
a splined BB.
Even then, most bikes are in for flat tires, derailleur adjustments, etc. and
not BB or crank failures which are relatively rare for any BB type. Even if
splined BBs had a high failure rate, most shops would not see it very often if
at all.
Todd Kuzma
Tullio's Big Dog Cyclery
LaSalle, IL 815-223-1776
http://www.tullios.com
Raleigh-Schwinn-Specialized
Bianchi-Waterford-Heron
GT/Dyno-Burley-Co-Motion
Jobst Brandt
>> Aside from that, the Shimano spline has failed enough to be a
>> subject of discussion here.
> Well the failure of the old square spindle has had MUCH more
> discussion here than the Shimano spline has. We know that -you-
> don't like the design but in practice, the people I've talked to
> that works on hundreds of bikes a week, haven't seen the failure
> rate you imply is the norm. Quoting you "Well that list of
> comparative assessments should be accompanied by some data." Lets
> see the numbers Jobst if these cranks have such a high failure rate
> as you imply.
I didn't suggest that they have a high failure rate and stated clearly
that from my perspective, the failures that have been reported could
be expected from my assessment of the interface. The repeated
loosening of retaining bolts and backlash buildup in the spline are
what I expected before users brought them up in this forum. I think
that a predictable failure that subsequently occurs is adequate proof
that the assessment of the design was correct.
In contrast, the ISIS standard has addressed these problems in what
appears to me to be a credible way. At first inspection I see a
better chance at success than other designs that have been proposed
and built.
> That's what I thought.
What did you think?
Jobst Brandt <jbr...@hpl.hp.com>
mchou
In layman terms, can you please elaborate why you think the ISIS design
wouldn't be subject to the same loosening and backlash issues that
the "other" splined interface suffers?
I'm not an ME, went over to the ISIS site and downloaded (and read)
their spec., but aside from positioning benefits I was at a loss why
the ISIS spline design would be any "better/less prone to failure" than
the existing ones.
Thanks,
Mark
In article <8s280l$ov5$1...@hplms2.hpl.hp.com>,
A Muzi
spindle snapped in half? I've seen 2 or 3 in my lifetime. Do you mean customer
assembled cranks lightly with no lubricant or torque and the crank tapers/splines
were damaged? all the time. Do you mean there's some design failure involved in
square or splined systems? What exactly goes wrong?
Todd Kuzma wrote:
> Stephe Thayer wrote:
>
> > Well the failure of the old square spindle has had MUCH more discussion here
> > than the shimano spline has. We know that -you- don't like the design but in
> > practice, the people I've talked to that works on hundreds of bikes a week,
> > haven't seen the failure rate you imply is the norm. Quoting you "Well that
> > list of comparative assessments should be accompanied by some data." Lets
> > see the numbers Jobst if these cranks have such a high failure rate as you
> > imply.
>
> Your figures are anecdotal as well. Frankly, it would be hard to get good
> figures or even good anecdotes as there are very few splined BBs in use
> compared to the square taper design. If your friends that work on "hundreds of
> bikes a week" (apparently only averaging a few minutes per bike - must be fast
> mechanics) would probably wait a several weeks before working on one bike with
> a splined BB.
>
> Even then, most bikes are in for flat tires, derailleur adjustments, etc. and
> not BB or crank failures which are relatively rare for any BB type. Even if
> splined BBs had a high failure rate, most shops would not see it very often if
> at all.
>
> Todd Kuzma
> Tullio's Big Dog Cyclery
> LaSalle, IL 815-223-1776
> http://www.tullios.com
> Raleigh-Schwinn-Specialized
> Bianchi-Waterford-Heron
> GT/Dyno-Burley-Co-Motion
--
Jobst Brandt
> Can you elaborate why you think the ISIS design wouldn't be subject
> to the same loosening and backlash issues that the "other" splined
> interface suffers?
The ISIS spline has a one degree taper per side that has a preload on
a 16mm long spline on which the crank sits on the spindle. The spline
diameter in the cranks has a major diameter of 22mm and a minor
diameter of 18mm diameter. Made with the precision that is specified,
something that is practical with current machines, the crank will
achieve its press fit before stopping against a fixed shoulder that
prevents lateral creep that is the bane of the square taper and it has
sufficient engagement so it does not suffer from spline overload or
elastic and clearance backlash that the Shimano design has.
Because the Shimano spline allows no significant press fit, having
only 3mm engagement, it has clearance that together with elastic
compression of the spline teeth, under pedaling load, cause enough
backlash to move the retaining bolt.
> I'm not an ME, went over to the ISIS site and downloaded (and read)
> their spec., but aside from positioning benefits I was at a loss why
> the ISIS spline design would be any "better/less prone to failure" than
> the existing ones.
The cranks is firmly seated on the spindle, something the Shimano
design achieves with a conical seat on a smooth bore. Because the
torque is transmitted by the end of the shaft into the far end of the
crank, this conical bore is subjected to torsional movement comprised
of deformation of both spindle and crank. To visualize this, metal
parts can be seen as varying harnesses of rubber. The distortions you
visualize are real and have fretting effects on the interface. I
think it is evident that the ISIS interface is more stable than any
others that have been proposed, the two elements, crank and spindle
having no areas where the creep or slide.
To see the results of such fretting motions, a square taper hardened
steel spindle shows erosion and rouge in the center of its flat faces.
Jobst Brandt <jbr...@hpl.hp.com>
Jobst Brandt
> This thread is opaque to me. When you guys speak of BB failure do
> you mean a spindle snapped in half? I've seen 2 or 3 in my
> lifetime. Do you mean customer assembled cranks lightly with no
> lubricant or torque and the crank tapers/splines were damaged? all
> the time. Do you mean there's some design failure involved in
> square or splined systems? What exactly goes wrong?
Well the ones that I caught were cracks in the corners of the square
and ones that I didn't catch were one spindle failure where the square
end broke off just inside the crank fit, there where the stress is
highest. Most of the dozens of cranks that I broke failed at the
small end, mainly in the pedal threads but also in the neck. The
spider cracks never did anything because these cranks broke elsewhere
first. The result is that the pedal attachment needs to be fixed and
the spindle attachment needs a redesign. The pedal end is simple and
I have done that but the spindle end is more difficult and I think the
ISIS is the best proposal yet offered.
Even though there are not many crank failures, they usually occur when
standing and usually case the rider to fall to the side where the
crank fails. This is seriously dangerous if it happened next to
traffic or at the edge of a cliff, so to speak. That is why even a
few rare failures are bad and that they occur at all is an indication
that the design is running near the limit.
Jobst Brandt <jbr...@hpl.hp.com>
Stephe
Jobst Brandt <jbr...@hpl.hp.com>
>
> I didn't suggest that they have a high failure rate and stated clearly
> that from my perspective, the failures that have been reported could
> be expected from my assessment of the interface.
The few failures that I have seen reported were more likely due to incorrect
instalation or perhaps a manufacturing defect than any design flaw, the same
thing that causes failures with the square taper interface. If there was
some sort of design flaw, I would think that there would be more that the
very occasional failure.
>> That's what I thought.
>What did you think?
That you have no data to back up your claim that there is a problem with
shimano's design while you demand data of others who post here. Typical was
all I was noting. Can you not admit that you may have been wrong about this
design having a problem? Of course you can't.
--
Stephe
Stephe
Todd Kuzma >
> Your figures are anecdotal as well.
>If your friends that work on "hundreds of
> bikes a week" (apparently only averaging a few minutes per bike - must be
fast
> mechanics) would probably wait a several weeks before working on one bike
with
> a splined BB.
>
> Even then, most bikes are in for flat tires, derailleur adjustments, etc.
and
> not BB or crank failures which are relatively rare for any BB type.
So we want to play a "data" game? 10 hours a day 5 days a week is 50 hours
correct? 100 bikes a week gives them 30 minutes a bike and if most just have
flats as you suggest, that's a pretty slow mechanic IMHO <G>
My point was at the bike shop I go to and know the guys at, they are the
highest volume bike shop in the state of GA (at least in sales if not
repairs as well) and they haven't seen the first one fail. Add all the guys
up (6 mechanics) and they do work on hundreds of bikes a week easily. I
frequent several local shops and haven't had one say they have seen a
problem. Seems like if there was a problem, the odds are someone would have
seen at least one don't you think?
> Even if
> splined BBs had a high failure rate, most shops would not see it very
often if
> at all.
>
Come on, if there was a high failure rate or there was a design problem of
any kind, as many bikes as are produced with them, we would have heard about
it by now. As sue happy as this country is they would HAVE to recall them as
well. The few posts that Jobst is refering to sounded like either a
manufacturing defect or an instalation error, the same thing that causes
problems with the square kind. He asks for data for someone's opinion but
gives none for his own while infering repeatedly that this design is flawed
yet it shows no signs of failures. All I wanted from him was to see the
data that supports there is a problem with this design. If they aren't
failing, how can someone say there is one? And why would you defend someone
saying there is one if there are no reports of failures to speak of? That
seems rather odd to me as well..
--
Stephe
Stephe
A Muzi <yell...@execpc.com> wrote in message
news:39e4e4f3$0$1584$3929...@news.execpc.com...
> This thread is opaque to me. When you guys speak of BB failure do you mean
a
> spindle snapped in half? I've seen 2 or 3 in my lifetime. Do you mean
customer
> assembled cranks lightly with no lubricant or torque and the crank
tapers/splines
> were damaged? all the time.
The latter is what is being discussed but Jobst seems to think a correctly
assembled/torqued shimano spline can fail in this fashion.
> Do you mean there's some design failure involved in
> square or splined systems?
No there isn't, but one engineers overactive imagination believes there is
and posts it regularly as fact...
--
Stephe
Helmut Springer
> up (6 mechanics) and they do work on hundreds of bikes a week
> easily. I frequent several local shops and haven't had one say
> they have seen a problem. Seems like if there was a problem, the
on since they have this annoying backlash'.
no statistic to be taken seriously as such, but it is noticed...
Grant
replaced the rings with XT rings and the very soft 7075 aluminium chainring
bolts with steel ones the shifting is better because the bolts don't come undone
or break like thge original ones and the XT rings seem to be harder than the
Truvativ ones. Even though i tried to get away from Shimano i couldn't simply
because their product is better. As for the bottom brackets that everyone has
already mentioned, i'm using the square taper version and as long as they are
done up right you don't have any problems. The arms seem stiff enough for me and
they look better than the Shimano ones. The self extracting crank bolts are
great too. Just make sure everything is loctited on and change the rings for XT
rings when you buy them and for steel or titanium bolts too.
Grant.