K2 / Proflex Riders Group
General => Tech Forum => Topic started by: kondilemma on March 23, 2006, 01:35:04 pm
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I've been lurking around the Shimano site, trying to answer some questions about building up the drivetrain on my 857 frame. Think I have it cased, with one exception.
--With the following drivetrain combo, what model of rear derail'r do I need--the short or long cage?
Cranks-- XT M760, 44-32-22T
and
Rear cogset M760 aq (11-32T)
I'm leaning toward the long cage model, but would like to poll the expertise out there. Haven't had time to get down to my LBS to pick their brains.
My brakes arrived in the mail today, so I'm itching to put this thing together ASAP. Now if the 3ft of snow outside would just melt...
thanks,
--brad
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the long cage is gonna give you more "cross chaining" options.You wont be able to ride in Big _ big.Not that you should :o
edit...you wont be able to ride big big with a SHORT cage..so yeah Long cage
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Long cage,
you only want a short cage if you run single front ring
and your main riding is Dh.
Simon.
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long cage -
our setups are why they make them -
OP
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Yep, long cage. Only drawback tendency for increased chainslap.
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Hehe, always one in the bunch. I run nothing but short cage old DX rear deraileurs without any problems on my Oz and my 5000. I run an 11-32 Tooth(T) 8-speed cassette on the rear. Up front I am running a 44T 32T and 20T. I never run my inner chainring past the middle gear in the back and never the large chainring past the middle from the outside in. I run the middle chainring on all gears 11-32.
Thunderchild
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never
thats a big word brotha....
thats wot i did too,untill racing along a road next to a stop bank(levee?) with a group of mates someone took a detour and shop up the bank....without thinking i hit the downshift stood up and bang....first broken chain,i had shifted big-big..... [smiley=diaper.gif]
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You gotta keep in mind that Thunderchild is a die-hard "they don't make 'em like they used to" guy. New and improved just doesn't seem to sink in very well - especially when it comes to drivetrains and tires.
;)
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Amen Matno! I'll pedal to that...[smiley=yawn.gif]
OK Kiwi, 99.9% of the time instead of never;D
Note on the short cage. It is interesting that the derailleur lists 28 tooth as the max, but it works on a 32 if you set it up correctly.
Thunderchild
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ummm Matno,taken a look around the room lately???
You gotta keep in mind that Thunderchild is a die-hard "they don't make 'em like they used to" guy. New and improved just doesn't seem to sink in very well - especially when it comes to drivetrains and tires.
;)
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HaHa. You're right. I guess he's not the only one, eh? Then again, I don't think I'm the only one who would balk at the idea of having thumb shifters on an Oz frame. (Not RapidFire, but rather the old kind that have a single lever on TOP of the bars...)
I guess we probably mostly fall into two groups: those who think like Thunderchild, and those who, like me, can't afford to buy something newer... Fortunately, we all have the common bond of liking to do things ourselves, improve what we have, and ride as much as possible!
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HaHa. You're right. I guess he's not the only one, eh? Then again, I don't think I'm the only one who would balk at the idea of having thumb shifters on an Oz frame. (Not RapidFire, but rather the old kind that have a single lever on TOP of the bars...)
I guess we probably mostly fall into two groups: those who think like Thunderchild, and those who, like me, can't afford to buy something newer... Fortunately, we all have the common bond of liking to do things ourselves, improve what we have, and ride as much as possible!
Nice bedside manner! ;)
Terry
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Thanks to all for the advice--and the bonus entertainment! [smiley=nod.gif]
Found an interesting tidbit about the XT crank I quoted above--my LBS says I'm better off with a RaceFace X-type Evolve XC crank. Better bang for the $$, to quote. Seems the Shmannos' bolt-on crank likes to sing, and the bearings go south in a hurry. Other than the M760 crankset, they like the rest of the XT components from that series.
But who knows what I'll end up with. Like Matno said above, I may not have the $$ to go XT and might have to resort to ebay, scrounging for castoffs. I've been shopping around for wheelsets lately, and nearly pooped my pantaloons at the prices. Suddenly those Sun Rhyno Lites on Deore Disc hubs look pretty good...which leads me right into my next new post.... ::)
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"Advances" in crank technology are not that great. Sure, the newer designs with the bearings outside the frame are stiffer and lighter, but do you think most people can tell the difference? I still have a SQUARE TAPER bottom bracket/crank on my single speed and I guarantee I can't tell the difference in stiffness between those and my Shimano Octalink BB's. The only real difference is a few grams of weight. Rode a new XT setup a few months back and couldn't tell the difference there either. As for bearings wearing out prematurely, no Shimano BBs have ever had a problem with that. ISIS bottom brackets, on the other hand, (including Race Face) have a reputation for nearly universally short life. A lot of people say they've had to replace them annually (which is WAY too short, in my opinion - unless you ride 10,000 miles in that year!)
As for my favorite choice, I'm still happily riding the first generation of Shimano LX Hollowtechs with the ES-70 BB (XT level BB). Shimano subsequently changed the compatibility of their BBs and cranks so that you couldn't mix and match LX and XT. I guess a lot of people were doing what I did and saving money on the crank (which was nearly identical to XT, but looked better - XTR gray) while still getting the nicer BB, which was significantly better than the cheaper ES50...
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Hey there!
Just thought I’d add my 2 cents worth. [smiley=laughing.gif]
Two of my Buddy’s run Race Face BB and both have had a problem with them staying tight. After applying some removable thread locker the problem was solved. But It’s a hard lesson to learn when out on the trails. As for me, I use the new Hollowtech II LX set up with a large 48t XTR ring. However I’ve learned that its great for building up speed on some sweet flat single track but a pain in the @ss when you have to ride over larger obstacles. Can I notice difference in smoothness, stiffness or what ever between my buddy’s Race Face and my Shimano? Nope. So I'd look for the deal when shopping.
As for my cassette I run a SRAM 11–34 for hill climbing. My bike (TREK Fuel 90) is a tad heavier so I opted for the larger granny gear. My rear derailleur is a long cage XT and I have only had one problem with a chain braking…and that was my fault for trying to ride in that super muddy mess…you could barely walk let alone ride! LoL :o
On a side note I still haven’t built up the 856 yet…but I do have all the parts so very, very soon I’ll have some pics of the beast.
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Love my hollowtech external type BB. Elegant simplicity, light, and rugged.
Hate the expensive tools required. [smiley=disbelief.gif]
Be vewy vewy careful not to crosstread these [smiley=doh.gif]
With one 856 using a medium Sheemano square/taper BB and one 856 using the XBB, I gotta say I can feel the difference under heavy load. The XBB is pretty darn stiff... (When I say heavy load, I mean 210#... [smiley=dead.gif])
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I've currently been riding the same old cast-iron hardtail for over a decade now, and haven't known anything else besides my Schmanno LX cranks with square tapered BB. Think I'm on my 3rd BB now.
I think it's time to upgrade! :)
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I have a Race Face Ti ISIS BB with Next LP cranks. RaceFace thought the cracks would be flexy for my weight (215+lbs), but the BB is stiff and soo smooth I never think about it. But I don't feel the swingarm on my 5500 is flexy either. Or maybe its the right amount of flexy for me. Who knows.
Rich
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I don't feel the swingarm on my 5500 is flexy either. Or maybe its the right amount of flexy for me. Who knows.
Rich
If you don't feel that the swingarm is flexy, you either have Simon's aluminum swingarm with sealed bearing conversion, or you really like side to side "give." I weigh 140, and if I could afford it, a frame with a stiffer swingarm would be high on the list. I'm used to it after 6 years, but that doesn't mean that I like it. Mostly it bugs me because every time it flexes sideways, I think about how that's side-loading my rear shock and prematurely wearing it out... On the other hand, I've landed some drops at scary sideways angles, and hardly noticed hitting the ground thanks to that rear carbon "sideways softtail"!
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In my experience it is difficult to separate tire and wheel lateral movement from swingarm movement. Wheels can flex very differently depending on cross pattern, spoke diameter and butting, rim type, tension, etc. Every rotation causes rim/spoke movement. If the swing arm is flexing from side to side it should affect the rolling line of the rear wheel as the wheel is clamped in with the quick release. Also, side to side should cause the main pivot and the shock pivot points to wear out. I have been impressed with how little the pivot bearings have worn on my Oz and 5000. Both have seen many years of year round riding with my 185 pounds. I would like to have an aluminum swing armed EVO to compare.
My thoughts
Thunderchild
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An Oz with carbon arm will be be more flexy (laterally)than
an Evo with a carbon arm,
there's alot of flex in that arm but the carbon mainframe pivot mount flexes considerably more
than the Evo,
I would of liked to of tried an Evo with an
aluminium s/arm ,sealed bearings and a propedal
shock preferably one with large eyelet bearings
and large shaft bearings with alot of overlap,
think that would make a fast informative ride,
think the Evo frame gets unfairly overlooked because
the carbon looks so cool IMHO,
in hindsight I would of liked to of owned one to play
around with.
Simon.
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In my experience it is difficult to separate tire and wheel lateral movement from swingarm movement.
I did a little experiment -
First I flexed the rear wheel just by holding the frame in one hand and the wheel in the other - which gave me about an inch of lateral flex
Then I firmly clamped the frame in a vise (actually, a large very solid door) and did the same thing. There was about 1/8" less flex.
Therefore, I concluded that most of the flex was in the swingarm, and not in the wheel itself. Besides, if the wheel were flexing that much (or even a 1/4"), I'm pretty sure it would have made the brakes rub at some point, which it didn't. Subjective test, to be sure, but my experience nonetheless...
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Next Oz overhaul I will try the flex experiment. I wonder what a 4-bar would do with such a test.
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I wonder what a 4-bar would do with such a test.
Solid as a rock would be my guess... (Especially a faux 4-bar like most of them are).
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An Oz with carbon arm will be be more flexy (laterally)than
an Evo with a carbon arm,
there's alot of flex in that arm but the carbon mainframe pivot mount flexes considerably more
than the Evo,
I would of liked to of tried an Evo with an
aluminium s/arm ,sealed bearings and a propedal
shock preferably one with large eyelet bearings
and large shaft bearings with alot of overlap,
think that would make a fast informative ride,
think the Evo frame gets unfairly overlooked because
the carbon looks so cool IMHO,
in hindsight I would of liked to of owned one to play
around with.
Simon.
My Evo with alum swingarm and factory sealed bearings is very rigid. It is a spare to my Oz, but has lots of potential.
On the note of alum swingarms, a conversation with K2 late last year before they sold to Iron horse, yielded a tidbit. No longer do they have any carbon swingarms of any kind. But they did have stock of aluminum Evo swingarms, for sale at $175 each.
Terry
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My Evo with alum swingarm and factory sealed bearings is very rigid. It is a spare to my Oz, but has lots of potential.
Terry
Terry bet there's not much weight difference
between the 2 either ???
talking main frame and s/arm assemblies.
Oh before anyone buys an Evo aluminium s/arm for
a carbon bike, don't won't fit too narrow to clear
mainframe,unless you cut it about but thats quite
involved.
Simon.
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Terry bet there's not much weight difference
between the 2 either ???
talking main frame and s/arm assemblies.
Oh before anyone buys an Evo aluminium s/arm for
a carbon bike, don't won't fit too narrow to clear
mainframe,unless you cut it about but thats quite
involved.
Simon.
Carbons and the Evos share the exact same geometry. And all my Oz parts will fit, even the caboneous swingarmeous(ACME).
You are right that the alum swingarm would need to be modified to fit the carbon. I like your job. But don't you think it would be lazier to grind away the frame? I mean it is only a frame, right? [smiley=laughing.gif] [smiley=turtle.gif][smiley=laughing.gif]
Now here is the ticket. Put the Evo alum swingarm on the Oz, 957 swingarm and strut on the Evo, and the Oz swingarm on the 957. [smiley=bomb.gif] [smiley=bomb.gif] [smiley=bomb.gif] [smiley=bomb.gif] [smiley=bomb.gif] [smiley=nod.gif]
Terry
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Now here is the ticket. Put the Evo alum swingarm on the Oz, 957 swingarm and strut on the Evo, and the Oz swingarm on the 957. [smiley=bomb.gif] [smiley=bomb.gif] [smiley=bomb.gif] [smiley=bomb.gif] [smiley=bomb.gif] [smiley=nod.gif]
Terry
Eh my head hurts now [smiley=laughing.gif]
Simon.