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Always Learning
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Discussion Starter · #1 · (Edited)
Okay, I know it's got to be 34.9mm clamp, bottom pull, bottom swing (traditional). I've got the XT M761 dual pull in the right size - but it's a pig. 178 friggin' grams for this porky. No way.

And I don't want to pony up for an XTR dual pull or the new XT dual pull at 155 grams. Can I use an older XT FD M751 (34.9 clamp, bottom pull bottom swing)? No dual pull on that critter and it is around 134 grams if I can find one on the net.

Any other lighter incarnations around that will work on the JET 9 frame. Remember, I'm going XC race light and consider the XT dual pull I own at 178 grams as kicked out of the game.:nono:

BB
 

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I personally wouldn't use anything other that the M771

BruceBrown said:
Okay, I know it's got to be 34.9mm clamp, bottom pull, bottom swing (traditional). I've got the XT dual pull in the right size - but it's a pig. 178 friggin' grams for this porky. No way.

And I don't want to pony up for an XTR dual pull or the new XT dual pull at 155 grams. Can I use an older XT FD M751 (34.9 clamp, bottom pull bottom swing)? No dual pull on that critter and it is around 134 grams.

Any other lighter incarnations around that will work on the JET 9 frame. Remember, I'm going XC race light and consider the XT dual pull I own at 178 grams as kicked out of the game.:nono:

BB
I had an X9 on there with my initial build but ordered the M771 model as recommended by Niner. The clearance on the rear brace was a little too close for my comfort. I could just see it hitting and breaking that brace and Niner saying "we told you so". If you do use some thing other than the one that is recommended, make sure there is plenty of clearance when the shock is FULLY compressed. I think this would be especially important since you bought the frame second hand and would have a hard time getting it warrantied anyway.

BTW, when are we gonna see some pics of how that build is coming?

another BTW BB, you will soon learn that the propedal on this bike is useless. I am totally convinced that the bike pedals so good that if I ever have to replace the rear shock, I will probaby look at something without a platform.
 

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Bruce, as Cruso said, look to use the 771 so you don't have to worry. I tried several different FDs on my new RIP9 with the same routing and only the new FDs worked. best bet, e-mail Niner and ask if with some finagalin you could get an older FD to work - doubt it , but worth an e-mail.
 

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Discussion Starter · #4 · (Edited)
cruso414 said:
I had an X9 on there with my initial build but ordered the M771 model as recommended by Niner. The clearance on the rear brace was a little too close for my comfort. I could just see it hitting and breaking that brace and Niner saying "we told you so". If you do use some thing other than the one that is recommended, make sure there is plenty of clearance when the shock is FULLY compressed. I think this would be especially important since you bought the frame second hand and would have a hard time getting it warrantied anyway.
This is starting to sound more difficult than the front derailleur situation on a Karate Monkey!:madman: (Which, by the way, is a Shimano FD M751 with a button head screw to replace the cable bolt.)

I've got to get out in the garage and put my FD M761 on there to see what this clearance and rear brace issue is all about so I can stop thinkering so much.

So no Shimano FD M511 (128 - 141g), no Shimano FD M751(134g)? Both are cheap and light and durable. And the M511 fits my stealth black mode.:D Heck, a true weight weenie would throw a road derailleur on the JET 9 in the right clamp size and make it work.

What about the XTR FD M971? The 2008 at 128g and can be had on the 'net for a reasonable cost - especially over in England due to the dollar to pound currency exchange. So I'll retract my earlier comment about not tossing cash at it as it's 1/2 the price over in the land of best English beef than the US of Anguish. I've got to order fast as the Fed's interest rate decision yesterday will slowly tank the dollar even more....

Edit: I just reviewed the JET 9 picture and set up thread and there are several folks running the XTR front mechanical. So it must work....

I guess the new XT FD M771's do come in at 155g (for the 2008 and 152g for the 2009) which is a tad lighter than my porky pig older version at 178g. I'll have to look through people's individual builds, but surely somebody is running the XTR on their JET 9 without problems... I'll be running 2 x 9, so that derailleur is not going to be sitting in close like a traditional triple granny spot. It will be a little more to the driveside for the inner ring on the 2 x 9 and will not extend as far for the outer ring as a triple. I will also be running 27T and 40T for my 2 x 9 - so the cage doesn't have to be a gigantic thing capable of handling 46-48T rings.

cruso414 said:
BTW, when are we gonna see some pics of how that build is coming?
Patience, Grasshoppers.

I could slap on what I do have (from my Sugar build) for instant photo gratification, but I've decided to juice the build in the weight weenie direction and that takes time. A lot of time to hunt everything down and get it just right. That's the fun part - so let me have some fun. Not to mention - it's winter. Ice, snow, -11 Monday, a balmy 8 yesterday and today looks like it might get up to 12 before it snows again. I'm riding my routine XC training in the basement on the exercise bike until March.;)

My parts are arriving for the build one by one, but considering the highest temperature we've had in the past few days is 8 degrees - I'm not about to stand out in the garage trying to piece anything together. I do have a 1500 watt space heater, but that would only get the temp up to 10 degrees after several hours.:cool:

Formula R1's won't even be out until February-March of '09 and ditto for the NoTubes ZTR Race 29"er wheelset. So don't expect to see those goodies on the bike until spring. I guess I could snap a few shots of where the bike stands at the moment to let you know it does exist. Bottom bracket (won on eBay), crankarms (snagged on eBay) and 2 x 9 rings (from Rotor) should arrive this week or next.

But I've got work to do on the crank arms. I've got to strip the hideous blue powder coating off and polish 'em up myself (again the problem of cold temperatures in the garage) - or send them off to Spectrum in Colorado for a sandblasting and refurbish to a stealth color.

Here's the before Fugliness I've got to deal with...



Thanks God these crank arms are thee Holy Grail of XC. I've got two pair of Next LP's, but the Turbines are the ticket to the kingdom and they are my chosen length of 180mm. So that makes the elbow grease work with the paint stripper, sand paper, Dremel, grinding wheel and of course a vat of Mother's all worth it.

I'm torn between going with silver arms or black arms for the final color. And of course, I have yet to order the best weight weenie chainring bolts in the right color for my needs. I could offset the entire crankset with a touch of anodized red to match the red bits on the frame - or I could go silver or black. I've got to see it all together before I decide.

In the end, Race Face refurbs look sharp. Here's a photo of Burner's Race Face Next LP's all stripped of their original shred red and polished up:



cruso414 said:
another BTW BB, you will soon learn that the propedal on this bike is useless. I am totally convinced that the bike pedals so good that if I ever have to replace the rear shock, I will probaby look at something without a platform.
Hmmmm....I'll have to experiment once I am up and running on something besides my driveway and the ice/snow covered streets around my house.

I appreciate the replies, but wonder if there is anyone out there who has made something lighter work on the JET 9. Chime in, if you have...:thumbsup: :thumbsup:

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you said a 2 x 9 - so why not use a DA or SRAM Force front. Super light. I am working on almost the same build - thinking full Rotor cranks, and avid ult. but everything else is about the same. Nice build.
 

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BB -

I am also going to the gripshift - have always loved them.

I am going to use a DA front or a SRAM force - super light and really made for 2 rings :thumbsup:

I am still going back and forth between the FSA 2 x 9 and the Rotor. I have a XTR 970 set on the shelf, I guess I could get some rings for it??

Why the rings on middle and outer on the cranks for you? Does that not give a bad chain line?
 

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Discussion Starter · #7 ·
chpfly said:
you said a 2 x 9 - so why not use a DA or SRAM Force front. Super light. I am working on almost the same build - thinking full Rotor cranks, and avid ult. but everything else is about the same. Nice build.
That's the question. Going 2 x 9 might make the Dura Ace with the 34.9 clamp a viable and light weight choice. I'll be trimming the front derailleur with a SRAM twist grip.

Although this is probably not the crankset I will run on the bike (I'll run the Turbines with the Q-Rings 27T/40T), it represents a good model for spacing to view:



That's a Stronglight 29T inner ring and a Race Face 42T outer ring (granny slot is empty).

Here's the "room" with my Shimano XT FD M761 (the porky pig at 178 grams!!!):



No cable hooked up to the derailleur yet, just checking the spacing. I can see if I was running a granny that a wide tire in the rear may have a chance to come into contact with the derailleur cage (same problem on the Karate Monkey with the short chainstays unless one uses the Monkey Nuts or runs 2x9, 1x9 or SS). But my cage will be moved out due to the 2 x 9 configuration - so not a problem.

Regardless, I don't see why another front derailleur model would not work. What do you think? A Dura Ace at sub 100 grams? Otherwise, why not the older XT M751 or the Deore M511?

Here's the M511 which is on closeout all over the 'net for $9 - $18:

 

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Discussion Starter · #8 · (Edited)
chpfly said:
BB -

I am also going to the gripshift - have always loved them.

I am going to use a DA front or a SRAM force - super light and really made for 2 rings :thumbsup:

I am still going back and forth between the FSA 2 x 9 and the Rotor. I have a XTR 970 set on the shelf, I guess I could get some rings for it??

Why the rings on middle and outer on the cranks for you? Does that not give a bad chain line?
One: Not with the right spindle length. Pictured is a 113mm spindle. I would get a BB with a shorter spindle if I were going to run this crankset on the JET 9. That and spacers would dial the 2 x 9 in so I could use all gears.

Two: Do you know of a 29T ring that fits the granny holes of a compact 5 arm 58/94 BCD crank? I could get a 27T from Action-Tec for $105 or have a custom 27T made for that BCD, but I think anything larger than that doesn't exist. Or I am unaware of it (which is quite possible).

In the case shown in the pictures, these cranks/rings are only shown as an example of 2 x 9 while I await my Turbines and Q-Rings (the 110/74 standard BCD pattern). Just pull in the cranks with a shorter spindle and chainline issues resolved as well as a better Q-factor.

The Turbines are square taper and the rings will be mounted on the granny and middle slots - so I will have to "push out" the cranks with a longer spindle and/or adjustable chainline with the Taperlock BB I'll be running. Square Taper is easier to do this with, but it can be solved with ISIS using spindle length and spacers if need be to a certain degree. I run the Middleburn Duo 2 x 9 in ISIS on my Dos Niner. But the Middleburn Duo spider is designed to take care of the chainline "problem" - so it's the easiest interface. They just need more choices in the rings than 29/32 and 42/44.

My worry on the road front derailleur running 2 x 9 is the range of cage movement available once you mount it on a mountain bike. Q-factor is narrower on a road bike, and running my rings "pushed out" for chainline performance may or may not work. I've never tried it with a road derailleur on a mountain bike full suspension frame before, so maybe I'm over-thinking again... Then again, the Holy Grail of XC race cranks (Turbines) have a narrow Q-factor which is why I wanted them. I will lose some of that pushing them out for dialing the drive side chainline for the best 2 x 9 performance, but certainly a lot better than external bearing set ups.
 

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I don't nor haven't done it yet, but I would say one huge advantage to not running a double setup using the granny would be to avoid all the trouble you can experience using the granny "space" - chain rubbing the tyre in muddy situations, gunking up your chain and possibly causing it to lock up completely and break something. It's something I guess I never though of before, but makes great sense, yes you'd need to bring the chainline in some to get a better line for the outer position, but would not need to bring it in nearly so far as to cause the middle to have the "Granny" situations.
 

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Discussion Starter · #10 ·
LyNx said:
I don't nor haven't done it yet, but I would say one huge advantage to not running a double setup using the granny would be to avoid all the trouble you can experience using the granny "space" - chain rubbing the tyre in muddy situations, gunking up your chain and possibly causing it to lock up completely and break something. It's something I guess I never though of before, but makes great sense, yes you'd need to bring the chainline in some to get a better line for the outer position, but would not need to bring it in nearly so far as to cause the middle to have the "Granny" situations.
Right. I use the Middleburn Duo as my guide for a 2 x 9 and chainline. Inner chainring on the Duo sits out a bit more than a granny on a triple and the outer ring sits in a bit more than on a triple. Great chainline so you can use all gears with both rings, no chainsuck issues and as you mention - the derailleur cage sits out far enough to avoid any tire/mud rub issues. I can easily see that being an issue on the JET 9 using a triple and a larger volume rear tire. Reminds of the Karate Monkey. I imagine outboard bearing set ups with wider Q-Factors have changed this a bit, but I wouldn't know from experience.

The good ole square taper BB allows one to get a variety of spindle lengths and adjust the chainline to dial it all in - clearance and line. You can do this to an extent with ISIS bb's using spindle length, spacers and some adjustment - but square taper wins the adjustment game. I've got both and I'm probably one of the few who have never owned any outboard bearing cranks to date.

The cranks arrived yesterday as I got a slip from the USPS to come to the post office and sign for them. I'll probably be shipping them off for sandblasting and a new color to Spectrum, but I might strip them myself and let 'em run polished silver.

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Oh come on Bruce, you know that's the way to go, it'll shave prob a whole 20g off them if you don't paint or PC them :D :p

Still are issues with external BBs and clearance, although I haven't loast a RD yet because of it I did on the trance before which had a very similar setup to the RIP clearance and pivot wise.
On the external BBs there is some adjustability if you're willing to do some work with them. I've done a bit of tuning and checking and got my XT's down to a 47.5mm chainline and can go even to a 45mm, but I don't like what I have to do to get it and also don't like it anyway.

Oh and one small FYI which you'll probably never need to use/know............if you break off your RD you cannot SS the CVA bikes, it's the one flaw in there design since the rockers go under the BB. I did this once and tried my best using all kinds of gear combos and if it weren't for my old rubber tube wrapped around the chainstay I would have eaten into the stay before I realised exactly what was happening - had to walk a good few miles because of that one.

BruceBrown said:
..........................................The cranks arrived yesterday as I got a slip from the USPS to come to the post office and sign for them. I'll probably be shipping them off for sandblasting and a new color to Spectrum, but I might strip them myself and let 'em run polished silver.

BB
 

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BB,
I have seen threads in the weight weenies forum showing use of DA fd's on triples so they should work OK in any position for 2x9 methinks...
Force and Rivals seem to have enough travel in them to cover 3 as well. At least it seemed that way when I was setting up mine for 2x9 (granny and mid).

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Vortechcoupe said:
I'm going to put a campy chorus CT (compact) front on my jet in the next week or two. This will be with a 960? XTR crank with just the granny and middle ring. 22/32. I'll report back.
Please report back once you have tested it out....have a spare Record CT front der I would like to do the same thing with
 

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well, my jet has not arrived yet but i was looking at a buddy's jet. I think the cable stop might be too high for it. The derailleur cage might not be able to sit low enough since i'll be trying to use the granny and middle ring. I'll report back. Frame should be here the 5th. I throw the cranks in and the front der 1st thing. That way i know if i need to go buy a xtr.
 

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update. the campy chorus front derailleur works ok....I need to get it to mount lower to shift to the middle ring better, but i'm using a xtr m960 crank and the 4 spider arms extend further then the middle ring. so i can't lower if any more with out hitting the spider arms. Also, the cable does come out at a pretty sharp angle (to the drive side) and it's rubbing the edge of the cable stop a little. But i think if i get a m970 or other normal spider cranks i could lower it a little 3-4mm and it would help.

I'll probably run it for a while as is. It will shift to the middle ring, just not as fast as it should but it's rare i put it down in the granny anyway.

I can post a pic if wanted.
 

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I'll get better pics later but here is an over all pic of the bike. I rode it today, 1st ride, for 4 hours and it shifter better then i thought it would. Never came over the middle ring between the spider either. Grip shift is a must since the cage is a little narrow for a 9 speed chain. But to sum it up, it works but a regular spidered crank would be much better, could mount the derailleur lower.

Now please keep in mind that this bike was slapped together in a day with parts from other bikes and friends so it's not the prettiest setup right now. But it rides great!

edit: weight is 26.58 lbs

https://farm4.static.flickr.com/3302/3189522700_1981a55ae0_b.jpg
 

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Looks pretty decent to me, although the silver stem doesn't work IMHO.

With regards to the FD,it should be at that height NO? I always though that you didn't really lower it when you went to a dual ring setup. Not sure who the crankset belongs to, but if they're yours and you plan on running it as a 2x9, then consider going to work on it and saw off the extra spider arm length and then polish then up nice and shiny :D

Vortechcoupe said:
I'll get better pics later but here is an over all pic of the bike. I rode it today, 1st ride, for 4 hours and it shifter better then i thought it would. Never came over the middle ring between the spider either. Grip shift is a must since the cage is a little narrow for a 9 speed chain. But to sum it up, it works but a regular spidered crank would be much better, could mount the derailleur lower.

Now please keep in mind that this bike was slapped together in a day with parts from other bikes and friends so it's not the prettiest setup right now. But it rides great!

edit: weight is 26.58 lbs

 
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