Racer Tech Thread
12-09-14, 03:40 PM
#826
commu*ist spy
when i first got di2 i was so blown away by the front shifting that i spent a long time thinking about the reasons i found it better.
i've written this before, but in some ways di2 front shifting (i'm talking 7970) felt slower to me than 7800 and 7900 mechanical. however, it shifted perfectly every single time.
too much time on my hands/lots of solo time on the bike made me realize that the reason mechanical gives the impression of a faster front shift (sometimes) is that when you push the lever to shift to the big ring, the chain is immediately jammed into the big ring. the actual shift doesn't happen until the chain hits the ramps, but there's noise and that jamming is something you can really feel, immediately.
with di2, there is of course the disconnect we have with a button press in an electronic system vs a lever that pulls a physical cable. it responds in a very controlled way (i'd say "perfect") that is the same every single time. as mentioned above, there's a slight overshift before it settles into position. the system knows where the chain is based on the positions of the front and rear derailleurs and can adjust the amount it overshifts and corrects for any combination.
it's hard to call di2 slow, and i only do so in comparison to the noise/impression that the mechanical system is doing something quicker when in reality the shift itself is not happening faster at all.
as doge's kid experienced, di2 still requires proper setup, and there's no excuse for not running a catcher, but a properly setup di2 system allows one to basically abuse the shifting in a way most of us wouldn't even attempt in a properly setup mechanical system.
@Ygduf -- i was just explaining this to a friend a few hours ago who just switched his bikes to di2. (his first comments were about how he was blown away by di2 for his TT rig.) i often swap between wheels with hubs from 4 manufacturers without any adjustment at all. the method shovel described for initial system setup definitely isn't necessary when swapping most wheels...you can often do the on-the-fly method described by globe -- the di2 equivalent of 1/8 turn in a mechanical system. if i've gotten a neutral wheel, i occasionally might need this adjustment. i happen not to need it with my own wheels.
although hub widths are supposed to follow a standard, in reality there's always a chance that a cassette on one wheel is offset just a bit relative to what your system is setup for. most commonly, it's just a slow shift that is noticeable in a gear or two and fixed by globe's method.
i know some otherwise intelligent people who cannot seem to figure out whether to add or release tension to make the proper adjustment in a mechanical system yet the di2 adjustment is more intuitive. (when in adjustment mode, the buttons work in by moving the pulleys in the same direction as regular mode, but instead of moving a full step (2.2mm), the RD moves 0.1mm--in the same direction.)
all else equal (FD, RD, chain, cassette, crank arms, spider), i haven't been able to tell the difference between ultegra and DA rings (7900/6700 & up), but i can tell the difference between shimano rings and others when shifting under load.
i've written this before, but in some ways di2 front shifting (i'm talking 7970) felt slower to me than 7800 and 7900 mechanical. however, it shifted perfectly every single time.
too much time on my hands/lots of solo time on the bike made me realize that the reason mechanical gives the impression of a faster front shift (sometimes) is that when you push the lever to shift to the big ring, the chain is immediately jammed into the big ring. the actual shift doesn't happen until the chain hits the ramps, but there's noise and that jamming is something you can really feel, immediately.
with di2, there is of course the disconnect we have with a button press in an electronic system vs a lever that pulls a physical cable. it responds in a very controlled way (i'd say "perfect") that is the same every single time. as mentioned above, there's a slight overshift before it settles into position. the system knows where the chain is based on the positions of the front and rear derailleurs and can adjust the amount it overshifts and corrects for any combination.
it's hard to call di2 slow, and i only do so in comparison to the noise/impression that the mechanical system is doing something quicker when in reality the shift itself is not happening faster at all.
as doge's kid experienced, di2 still requires proper setup, and there's no excuse for not running a catcher, but a properly setup di2 system allows one to basically abuse the shifting in a way most of us wouldn't even attempt in a properly setup mechanical system.
@Ygduf -- i was just explaining this to a friend a few hours ago who just switched his bikes to di2. (his first comments were about how he was blown away by di2 for his TT rig.) i often swap between wheels with hubs from 4 manufacturers without any adjustment at all. the method shovel described for initial system setup definitely isn't necessary when swapping most wheels...you can often do the on-the-fly method described by globe -- the di2 equivalent of 1/8 turn in a mechanical system. if i've gotten a neutral wheel, i occasionally might need this adjustment. i happen not to need it with my own wheels.
although hub widths are supposed to follow a standard, in reality there's always a chance that a cassette on one wheel is offset just a bit relative to what your system is setup for. most commonly, it's just a slow shift that is noticeable in a gear or two and fixed by globe's method.
i know some otherwise intelligent people who cannot seem to figure out whether to add or release tension to make the proper adjustment in a mechanical system yet the di2 adjustment is more intuitive. (when in adjustment mode, the buttons work in by moving the pulleys in the same direction as regular mode, but instead of moving a full step (2.2mm), the RD moves 0.1mm--in the same direction.)
all else equal (FD, RD, chain, cassette, crank arms, spider), i haven't been able to tell the difference between ultegra and DA rings (7900/6700 & up), but i can tell the difference between shimano rings and others when shifting under load.
also, what are types of situations where someone would upshift on a di2 that would derail a mechanical chainring? the only scenario I can think of is climbing and getting over the hump.
also, are shimano chainrings still the best for front shifting? My training bike has a FSA crankset with shimano shifters, and does a really good job. My sram force on the racing bike sucks donkey dick at front shifting.
Last edited by spectastic; 12-09-14 at 03:43 PM.
12-09-14, 04:35 PM
#827
Senior Member
That rule applies to only regular threads following the right-hand rule, and people should try it on a left side pedal or a right side threaded bottom bracket cup to see where it gets them. The inability to understand regular thread vs reverse thread and having to rely upon a meme is a sign of the failure of the secondary education system as apparently no one paid attention in physics class. If there's one takeaway from physics class that's actually useful in real life, it'd be this.
12-09-14, 06:18 PM
#828
Senior Member
Join Date: Sep 2008
Location: ?
Posts: 2,300
Bikes: i may have bike(s)
Mentioned: 6 Post(s)
Tagged: 0 Thread(s)
Quoted: 46 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
There is no exception to Roy G Biv. Exception to the right hand rule are abound in real life, especially cycling. Or say when you try to weld or use H2 gas.
that and the fact that righty-loosey is a bit more complicated. Righty? Right of what? If i'm looking head on at a screw what does it mean to turn it right? There's only cw and ccw
that and the fact that righty-loosey is a bit more complicated. Righty? Right of what? If i'm looking head on at a screw what does it mean to turn it right? There's only cw and ccw
), cw and ccw are a matter of perspective as well. Imagine looking at a clock from the reverse side, or if it was "see through." It would rotate ccw from this perspective, hence physicists use a right hand rule to describe rotations. (axial vectors, etc.) A clock when looking at it from the usual side is said to rotate "into the plane of the clock." Someone looking from the other side, using the same rule (which I will not get into) would agree. Hence, it is now universal.
12-10-14, 10:46 AM
#829
Member
Join Date: Jun 2014
Posts: 46
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 11 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
There is no exception to Roy G Biv. Exception to the right hand rule are abound in real life, especially cycling. Or say when you try to weld or use H2 gas.
that and the fact that righty-loosey is a bit more complicated. Righty? Right of what? If i'm looking head on at a screw what does it mean to turn it right? There's only cw and ccw
that and the fact that righty-loosey is a bit more complicated. Righty? Right of what? If i'm looking head on at a screw what does it mean to turn it right? There's only cw and ccw
Obviously it's based on looking at the head because that is how you drive the vast majority of fasteners. Not to mention that the actual manufacturing/machining of threads is based on right/left, so that is where the definition came from in the first place.
Yes, there are times you access them from behind. But you just reverse the direction and everything works fine.
As to the exceptions, they are just that... exceptions. Far easier to learn those few oddities and apply the general rule to everything else.
I always think of drive-side BB threads as goofy and do them "backwards" of the Right-Tight.
Pedals are easy with "Forward/On, Back/Off" meaning rotating the wrench/thread forward or backward with respect to the bike.
12-10-14, 02:47 PM
#830
These Guys Eat Oreos
Join Date: Jun 2010
Location: Superior, CO
Posts: 3,432
Bikes: Yes
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 13 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
So I have about 750 miles now on swisstop black prince pads. My review? They suck. In all conditions. I'm going back to yellow. Even though they make my wheels yellow.
12-10-14, 03:09 PM
#831
soon to be gsteinc...
Join Date: Oct 2010
Location: Nayr497's BFF
Posts: 8,564
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I've got some Grey Zipps on now. THey work pretty well. Swisstop Yellow were really good but didn't last me all that long.
12-10-14, 03:44 PM
#832
Senior Member
I should probably think about getting new brake pads. Been using the same set for 3 years now.
12-10-14, 03:59 PM
#833
OMC
Join Date: Oct 2010
Location: South Louisiana
Posts: 6,960
Bikes: Specialized Allez Sprint, Look 585, Specialized Allez Comp Race
Mentioned: 199 Post(s)
Tagged: 0 Thread(s)
Quoted: 461 Post(s)
Liked 116 Times
in
49 Posts
I recently transferred my carbon wheels to my new (to me) TT bike and put the aluminim wheels and pads back on the Look. So much nicer...
__________________
Regards,
Chuck
Demain, on roule!
Regards,
Chuck
Demain, on roule!
12-10-14, 07:53 PM
#835
Senior Member
Join Date: Jun 2010
Location: Western MA
Posts: 15,669
Bikes: Yes
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
12-10-14, 09:17 PM
#836
Senior Member
Thread Starter
Join Date: Aug 2007
Posts: 4,449
Mentioned: 64 Post(s)
Tagged: 0 Thread(s)
Quoted: 693 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
any discussion of brake pads (esp carbon-specific) is incomplete without mentioning the wheels.
e.g., HED wheels respond better to different pads than zipps, IME.
anyone find anything better than zipp platinums for zipps (that are still recommended by zipp)? i've found the platinums to be good enough that i never experimented with others lately. the older (hard to find) black zipp carbon pads were really, really good but wore down quite fast.
e.g., HED wheels respond better to different pads than zipps, IME.
anyone find anything better than zipp platinums for zipps (that are still recommended by zipp)? i've found the platinums to be good enough that i never experimented with others lately. the older (hard to find) black zipp carbon pads were really, really good but wore down quite fast.
12-10-14, 10:13 PM
#837
Senior Member
Join Date: Jan 2014
Location: Southern California, USA
Posts: 10,474
Bikes: 1979 Raleigh Team 753
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3374 Post(s)
Liked 371 Times
in
253 Posts
Fastest 16 metal spoke wheel for a flat 12 mile TT (cheap is good)?
No trolling or arguments her (always I have an opinion).
As posted earlier - and no one responded - Puppy has a TT on mass start bike and all the big boys (his age) show up. Wheels must have 16 metal spokes.
No trolling or arguments her (always I have an opinion).
As posted earlier - and no one responded - Puppy has a TT on mass start bike and all the big boys (his age) show up. Wheels must have 16 metal spokes.
12-11-14, 06:25 AM
#838
Senior Member
Join Date: Jun 2010
Location: Western MA
Posts: 15,669
Bikes: Yes
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
A Mavic Aksium would probably fit the bill but they suck in cross winds. Any wide flat bladed spoked wheel is going to suck in cross winds. Front wheels are extremely easy to build. I'd go custom with an offshore carbon 58-60mm Firecrest profile rim and CX-Ray spokes on any hub.
12-11-14, 08:09 AM
#840
Senior Member
Does the rim have to be metal or can it be carbon/faired?
__________________
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
12-11-14, 10:56 AM
#841
Senior Member
Join Date: Jan 2014
Location: Southern California, USA
Posts: 10,474
Bikes: 1979 Raleigh Team 753
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3374 Post(s)
Liked 371 Times
in
253 Posts
Good question. Last year carbon was fine. There is a world trend to disallowing larger profiles rims and talk about eliminating carbon for younger. There is generally some blurb about keeping the cost down and making it affordable. Announcing rule changes within a couple months of an event is not the best way to make things affordable. I don't expect Puppy to have anything different than his top competitors. If they had just left it to TT bikes - we all have those and would have saved some money. The year after we bought a TT bike USAC eliminated the use of TT bikes until U15.
2014 rules: https://www.wmrc.org/sites/default/fi...ntChange_0.pdf
I may do the build my own front.
Seems the pre-built non-name all have 20 spokes. Any links to an 88 with 16 spokes?
2014 rules: https://www.wmrc.org/sites/default/fi...ntChange_0.pdf
I may do the build my own front.
Seems the pre-built non-name all have 20 spokes. Any links to an 88 with 16 spokes?
Last edited by Doge; 12-11-14 at 04:29 PM.
12-11-14, 08:18 PM
#842
Senior Member
Join Date: Jan 2014
Location: Southern California, USA
Posts: 10,474
Bikes: 1979 Raleigh Team 753
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3374 Post(s)
Liked 371 Times
in
253 Posts
This one should get its own thread - but as its a Tech item ...
Anybody use one? This may be as useful as power to see your limits. Just a bit big and awkward. Might not be legal to race with.
BSXinsight lactate threshold monitor goes on sale - BikeRadar
Anybody use one? This may be as useful as power to see your limits. Just a bit big and awkward. Might not be legal to race with.
BSXinsight lactate threshold monitor goes on sale - BikeRadar
12-11-14, 08:36 PM
#843
Senior Member
Thread Starter
Join Date: Aug 2007
Posts: 4,449
Mentioned: 64 Post(s)
Tagged: 0 Thread(s)
Quoted: 693 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Originally Posted by spectastic
also, what are types of situations where someone would upshift on a di2 that would derail a mechanical chainring? the only scenario I can think of is climbing and getting over the hump.
most upshift derailments i have experienced/seen have been due to improper setup of the FD (height, high limit screw). di2, IME, has a higher tolerance for bad setup here as the chain moves only as much as necessary. in a mechanical setup, if the high limit screw is too loose then it is easier to push the chain to the outside.
dropping a chain to the inside can be caused by poor setup. IME di2 does it less but is not completely immune. a chain catcher is still a good idea.
any shifts under heavy load (mechanical) create scenarios that cause either a slow upshift or a really abrupt reduction in chain tension (downshift). di2 remains very precise in both cases.
Originally Posted by spectastic
also, are shimano chainrings still the best for front shifting? My training bike has a FSA crankset with shimano shifters, and does a really good job. My sram force on the racing bike sucks donkey dick at front shifting.
the forged shimano chainrings are stiffer in a way that produces better shifting than any of the machined rings. most lighter (machined) rings i've tested, e.g. stuff like the specialized s-works SL rings, were flexy -- not in a way that meant power was not getting to the drivetrain but in a decrease in shifting performance under load. slower shifting, some vague front shifting, and more frequent (though still not common) derailments.
the sram red sprinter rings were a step up over the sram red non-SPR rings i tried. do they still make the 2 versions?
could also be related to shaman's tooth profile, too.
i haven't tried praxis forged rings in a controlled environment.
didn't realize there was more than a theoretical difference in rings until i tested them. in the past i could never isolate the effect of the rings vs the crankset (and often the bike/bb was different, too).
just my $0.02. YMMCAWV.
12-11-14, 08:53 PM
#844
Senior Member
Join Date: Jun 2010
Location: Western MA
Posts: 15,669
Bikes: Yes
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 9 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Not to my knowledge. That changed with Yaw. There is Red Yaw (10sp) and Red 22 (11sp). I am fitting Red 22 rings before sending my SRM in for service in a week or so.
12-11-14, 08:57 PM
#845
Senior Member
Thread Starter
Join Date: Aug 2007
Posts: 4,449
Mentioned: 64 Post(s)
Tagged: 0 Thread(s)
Quoted: 693 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
i've tested lots of rings against shimano rings, but i've not tested either of those rings. it's possible that they are better than the shimano rings i've tested.
12-15-14, 10:26 AM
#846
soon to be gsteinc...
Join Date: Oct 2010
Location: Nayr497's BFF
Posts: 8,564
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
I've run Red, DA, DA TT, Osymetric (new and old) and Q-Rings. I find that the 54T Aero Q-Rings are quite stiff and am quite happy with them. The aren't as quick on the upshift as the round rings but I don't spend much time in the small ring so it isn't much of a concern.
12-15-14, 10:54 PM
#847
Senior Member
Sort of relevant. I just saw an article that said that no ProTour teams on SRAM for next year. Is that relevant to the typical amateur racer? Wondering out loud.
__________________
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
"...during the Lance years, being fit became the No. 1 thing. Totally the only thing. It’s a big part of what we do, but fitness is not the only thing. There’s skills, there’s tactics … there’s all kinds of stuff..." Tim Johnson
12-16-14, 09:17 AM
#848
Senior Member
Maybe not this year, but it's kind of a problem for them if it continues. I guess the question is WHY there are no World Tour teams on SRAM. Is it less juicy sponsorship agreements? I guess that could be, but Campy is no more favorable, possibly worse. Maybe a perception of fewer options for teams? Shimano and Campy both have mechanical and electronic groups available. SRAM's electronic group probably won't be released until at least the 2016 model year. Maybe 2017 or later. So that could be. There's also a possible perception that SRAM has reliability and/or quality issues, and that could be a big problem, too.
12-16-14, 09:41 AM
#849
soon to be gsteinc...
Join Date: Oct 2010
Location: Nayr497's BFF
Posts: 8,564
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 2 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Interesting.
12-16-14, 09:46 AM
#850
Senior Member
Join Date: Jan 2014
Location: Southern California, USA
Posts: 10,474
Bikes: 1979 Raleigh Team 753
Mentioned: 153 Post(s)
Tagged: 0 Thread(s)
Quoted: 3374 Post(s)
Liked 371 Times
in
253 Posts
It was given as a reason it was so easy for junior teams to get SRAM stuff on their Specalized bikes, but not so much Shimano.