# 2x9: Middleburn RS8 ISIS Duo = 522g (no BB)



## Cheers! (Jun 26, 2006)

Here is my 2x9 choice.

Middleburn Duo RS8 ISIS. Purchased from https://chainreactioncycles.com

Hardcoat 42T and 29T rings. 
175mm length
Bottom Bracket choice not made yet. Probably 108mm Token TK872CT or KCNC Scandium ISIS.

Choice were between:
-Extralite E-Bones 68mm BB, 30T + 44T 
(lightest, most expensive, some hate the bearings, some say too flexy... in the end it was the price that turned me off to try them)

-Rotor Agilis 2x9 
(kinda heavy, and from an engineer's point of view the DTT thing is stupid)

-Raceface Next LP w/ Phil Wood BB 
(I couldn't find a nice example of Compact 5 arm on ebay, I didn't have the phil wood BB, so the price was not goign to be cheap)

-XTR M952 NOS w/ 94 BCD spider used for Single speed guys 
(found several nice examples on ebay for good price, I also found a compact spider for it, but the weight was going to be 700+g heavy)

-TA Specialities Carmina crank 
(ok price, heaviest choice, hard to find... https://weightweenies.starbike.com/forum/viewtopic.php?t=27852&highlight=carmina)

Here are the pics. Enjoy.


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## BruceBrown (Jan 16, 2004)

Cheers! said:


> Here is my 2x9 choice.
> 
> Middleburn Duo RS8 ISIS. Purchased from http://chainreactioncycles.com
> 
> Hardcoat 42T and 29T rings. Bottom Bracket choice not made yet. Probably 108mm Token TK872CT or KCNC Scandium ISIS.


Congrats!! Nice choice. I've got the _heavier_ Middleburn 2x9 (RS7 180mm custom black anodized arms with the hardcoat 29/42T rings). Add in the Crank Brothers ISIS 113mm spindle BB and it all works out to a decent set.

I should list my Next LP cranks (I've got shred red square taper and black ISIS - both in 175mm) on eBay and or here in the classifieds at some point since I don't use them any more. I moved to 180's a while back and have a lot of 175mm stuff sitting around in the parts bin. All the Race Face cranks can be refurbished either with a polish or a sandblast and powdercoat to take on a "new life".

My new JET 9 will be sporting refurbished color Race Face Turbine 180mms(425g) with a Taperlock Ti 110mm bottom bracket (166g) and the Rotor 2 x 9 Q rings (95g). That set up should end up with a decent weight depending on the final weight of crank bolts and chainring bolts. I've raced the Middleburn 29/42 with a 11/34 cassette on my 29"er for the past two seasons. I made every climb, but was on the teather a few times on the steepest stuff. I'm hoping the 27T up front will help my climbing with the big wheels on the steepest stuff of XC racing and will be a nice combination.

Middleburn used to have the Duo in 27/40 combo back during the RS1 days. I wish they would bring that combination of Duo rings back - especially so one could run a lighter cassette in the rear or for the big wheel crowd, allow 29"er's to enjoy a more appropriate 2x9 combination than the 29/42 affords. Join me in emailing them if you agree....;-)

BB


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## Cheers! (Jun 26, 2006)

BruceBrown said:


> Nice choice. I've got the heavier Middleburn 2x9 (RS7 180mm custom black anodized arms with the hardcoat 29/42T rings) that comes in around 560g for everything. Add in the Crank Brothers ISIS 113mm spindle BB and it all works out to a decent set.
> 
> I should list my Next LP cranks (I've got shred red taper and black ISIS - both in 175mm) on eBay and or here in the classifieds at some point since I don't use them any more. I moved to 180's a while back and have a lot of 175mm stuff sitting around in the parts bin.
> 
> ...


Thanks! I thought about getting my anodized too. But looking at the finish I think I'll wait till they are banged up a bit then get them anodized. I hope I didn't make a mistake going for ISIS... (fingers crossed)


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## BruceBrown (Jan 16, 2004)

Cheers! said:


> Thanks! I thought about getting my anodized too. But looking at the finish I think I'll wait till they are banged up a bit then get them anodized. I hope I didn't make a mistake going for ISIS... (fingers crossed)


You didn't make a mistake. If you want to talk about a solid ISIS bb, the Crank Brothers (with 5 year warranty) has been a champ the past 2 years. The Ti version weighs 180 which might be more weight than you want to go, but it's a work horse. The chromo is 220 and equally good.

I've got the RS7 in ISIS and using a 113 spindle on my Dos Niner - the shifting is perfect!! I can use every gear on both rings (I use the X.0 twist to trim the front derailleur). At least on my Dos Niner with the 68mm bb shell, I don't see any way I could use a shorter spindle on the drive side, so 113mm is dandy. On the left, there looks to be a pair of mm's to play with by bringing the crank arm in towards the frame for Q factor.

As far as anodizing....it would rub off anyway. My black arms have shoe rub marks. It looks nice when new, but unless your shoes don't rub it's probably not worth it. If you do ever anodize - it's nothing a sharpie can't take care of up to a certain point....

Enjoy your new 2 x 9.

BB


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## BruceBrown (Jan 16, 2004)

Cheers! said:


> Thanks! I thought about getting my anodized too. But looking at the finish I think I'll wait till they are banged up a bit then get them anodized. I hope I didn't make a mistake going for ISIS... (fingers crossed)


Dang. I forgot to ask. Is this new 2 x 9 for the Kona or another project?

BB


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## Kris (Jun 15, 2004)

Sweet, I love my RS7 Duo, something about the setup screams "hammer me"! I got mine from CRC a couple of years back, they mounted the spider ring before shipping which made me happy as I didn't have the tool. I wonder why they stopped doing this?


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## BruceBrown (Jan 16, 2004)

Kris said:


> Sweet, I love my RS7 Duo, something about the setup screams "hammer me"! I got mine from CRC a couple of years back, they mounted the spider ring before shipping which made me happy as I didn't have the tool. I wonder why they stopped doing this?


The Shimano Spider lockring tool is not a bad thing to own as it's nice to have around to tighten things up if need be. I think they run about $10 - 15 and can be picked up at your LBS (or ordered). I bought one and have used it several times on my Middleburn. You never know if you might have to take your rings off and true them after a log hit or cleaning or replacing, etc... .

I didn't know they used to mount the spider with the lockring before they shipped. Is it easier to pack and ship things unmounted? Who knows?

BB


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## Cheers! (Jun 26, 2006)

BruceBrown said:


> Dang. I forgot to ask. Is this new 2 x 9 for the Kona or another project?
> 
> BB


Something else... It will be even lighter.


What can I say... The chase is better than the catch.


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## chpfly (Oct 22, 2007)

Cheers - 

Why did you not look at the FSA 2 x 9 set up?

And what is the DTT on the Rotor that you don't like. I am looking at the FSA or Rotor for a 29er I am building.


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## Cheers! (Jun 26, 2006)

chpfly said:


> Cheers -
> 
> Why did you not look at the FSA 2 x 9 set up?
> 
> And what is the DTT on the Rotor that you don't like. I am looking at the FSA or Rotor for a 29er I am building.


FSA one is too heavy... And someone posted a picture of a failed FSA crankarm over on the weight weenie forums (the other forum). Also the fact that the BCD is not a standard one and you are forced to run FSA rings.

DTT is a double threaded bolt.










http://weightweenies.starbike.com/forum/viewtopic.php?t=37845&highlight=fsa*


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## limba (Jan 9, 2004)

Have you tried these cranks yet? I know you had clearance problems and trouble with your front derailleur. Have you used the bike yet? How's the shifting compared to Shimano or Race Face?
Can you feel any flex?


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## Cheers! (Jun 26, 2006)

limba said:


> Have you tried these cranks yet? I know you had clearance problems and trouble with your front derailleur. Have you used the bike yet? How's the shifting compared to Shimano or Race Face?
> Can you feel any flex?


I have ridden the bike on pavement only. The trails are off limits for spring melt.

Can you define clearance problems? If you are asking if I can make the front derailleur shift the chain from the 29T to the 42T and back to the 29T the answer is yes. I can also ride 42T front chainring and 32T cog in the back. I can also ride 29T front chainring and 11T cog in the rear without any rubbing. This is true of both the Dura-Ace 7800 FD w/ The speen.de top pull converter. It is however not a very good setup as the force required by your thumb to shift the Dura-Ace derailluer is extremely high. I have since installed a XTR FD-M970 derailleur on the bike. The force required by my thumb is 10X less.

Shifting is fine. It is not as smooth or seemless as Shimano Chainrings, but then again Shimano chain rings shift the best out of all chain rings on the market. I'm also use a 10 speed chain. KMC X10SL chain to be exact.

I do not feel any flex. Mind you my whole bike isn't exactly the stiffest bike out there. Titanium spoked wheels on ultra light weight rims. Titanium frame, flexy light weight stem... everything on the bike flexes a bit. It is not a Cannondale or Klein aluminum hardtail from the 90s, nor is it a modern carbon fibre ultra stiff frame.


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## limba (Jan 9, 2004)

The clearance problems I brought up were your chainrings. I remember your chainrings were too close to your frame. What bottom bracket did you end up using?


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## Cheers! (Jun 26, 2006)

THe original BB I tried was a 108x68mm road bottom bracket. Everything fit, but everything was too close for comfort. I ended up with a 113x68mm American Classic Bottom Bracket.


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## 743power (Sep 25, 2007)

no luck with that 952 on ebay cheers?

The more I research 2x9, the more it looks like the middleburn is the way to go.


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## Cheers! (Jun 26, 2006)

743power said:


> no luck with that 952 on ebay cheers?
> 
> The more I research 2x9, the more it looks like the middleburn is the way to go.


None. I bidded on one, but when I talked to the seller I asked if it was top pull. The box in the picture he/she had said it top pull, but his reply was bottom pull. The picture of the FD hinted it was bottom pull but I couldn't tell because of hte fuzzy image. I decided not to re-bid when someone beat my bid.

I'm still on the hunt though... I see a lot of M950 derailleurs but the 952 TP, 34.9mm clamp is rare.


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## JaLove (Dec 24, 2006)

May be a silly question but are the chainring bolts standard (double) size bolts as they seem to be from the pictures, or are they shorter than normal bolts--as in BMX or single-speed size?


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## Cheers! (Jun 26, 2006)

JaLove said:


> May be a silly question but are the chainring bolts standard (double) size bolts as they seem to be from the pictures, or are they shorter than normal bolts--as in BMX or single-speed size?


To be honest. I don't know. I have not really had to play around with cranksets and chainrings much. This was actually the first time I put a crankset together. Prior to that the XTs and XTRs all came pre assembled in a box and I just installed it onto the bike.

I did follow the Middleburn instructions and added Loctite 222 to the alloy chain ring bolts and torqued them to 80 inch-lbs.

Here are the bolts that were supplied with the Middleburn DUOs


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## JaLove (Dec 24, 2006)

Cheers! said:


> To be honest. I don't know. I have not really had to play around with cranksets and chainrings much. This was actually the first time I put a crankset together. Prior to that the XTs and XTRs all came pre assembled in a box and I just installed it onto the bike.
> 
> I did follow the Middleburn instructions and added Loctite 222 to the alloy chain ring bolts and torqued them to 80 inch-lbs.
> 
> Here are the bolts that were supplied with the Middleburn DUOs


I appreciate you taking the time to measure! I'm still on the fence between these and a set of Race Face Deus with King BB and TA rings. I'm wondering how much different the 42-28 combo will be from a 42-27 combo.


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## Cheers! (Jun 26, 2006)

I'm not a fan of the RaceFace Deus crankset where it has the so called "X type" bottom bracket setup. The chainline is adjustable via plastic washers and such. It's not an easy system to setup correctly. A lot of people fail to setup the spindle and bottom correctly and as a result the crank arm gets loose and the threads and splines of the axle/spindle get damaged and the crankset is junk.


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## limba (Jan 9, 2004)

I've been reading and saving every 2x9 thread I found over the last couple of weeks. If you're thinking about the Middleburn this thread is worth a read.

http://forums.mtbr.com/showthread.php?t=496792&highlight=Middleburn+duo


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## Cheers! (Jun 26, 2006)

Here is how they look installed. Ignore the Dura-Ace Front Derailleur. It has been replaced with a Shimano XTR M970 FD as the Dura-Ace 7800 won't shift the chain to the Big Ring with a 113mm ISIS BB. The Dura-Ace FD could do it with a 108mm ISIS BB, but the clearance was too tight betwen the crank arms and the chainstays.


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## Limon (Jan 26, 2004)

Cheers! said:


> Here is how they look installed. Ignore the Dura-Ace Front Derailleur. It has been replaced with a Shimano XTR M970 FD as the Dura-Ace 7800 won't shift the chain to the Big Ring with a 113mm ISIS BB. The Dura-Ace FD could do it with a 108mm ISIS BB, but the clearance was too tight betwen the crank arms and the chainstays.


love those cranks and very good pics.


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## Jake Pay (Dec 27, 2006)

That's a sweet crankset, enjoy








~Jake


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## nino (Jan 13, 2004)

*instead...*



Cheers! said:


> The Dura-Ace FD could do it with a 108mm ISIS BB, but the clearance was too tight betwen the crank arms and the chainstays.


Instead of installing a 113mm axle which adds 5mm to the Q-factor i would have added a 1mm spacer to the right side cup to make more room for the chainrings. You won't notice a 1mm offset in cranks but you can feel 5mm...and most probably with the shorter 108mm axle the chainline would be better for 2x9 as well, right?

anyway - they look good.


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## Cheers! (Jun 26, 2006)

I tried a 2mm spacer on the drive side BB cup. I also tried a 1mm spacer on the drive side BB cup. 

Couldn't do it. If I added any spacer to the drive side cup the left crank pulled in. I could squeeze the non drive side crank arm and left side chainstay with my hands and have them make contact with each other. At that point I just fessed up and got a 113mm bottom bracket. I didn't want to damage my new Ti frame and my new crankset. 

In theory I could have gone with a 40T DUO chainring, but I couldn't find one easily, and I wanted the extra 2 teeth for double track speed between single track sections during races.


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## nino (Jan 13, 2004)

Cheers! said:


> I tried a 2mm spacer on the drive side BB cup. I also tried a 1mm spacer on the drive side BB cup.
> 
> Couldn't do it. If I added any spacer to the drive side cup the left crank pulled in. I could squeeze the non drive side crank arm and left side chainstay with my hands and have them make contact with each other. At that point I just fessed up and got a 113mm bottom bracket. I didn't want to damage my new Ti frame and my new crankset.
> 
> In theory I could have gone with a 40T DUO chainring, but I couldn't find one easily, and I wanted the extra 2 teeth for double track speed between single track sections during races.


you mean the arms made contact? I thought it was the rings therefore my suggestion.


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## chomxxo (Oct 15, 2008)

Excellent choices. I have almost the same thing except I went with RS7 Duo to get 180mm length and Eggbeaters 2 Ti for the greater rider weight limit, although I'm down to 186 lbs naked now  

I couldn't be happier with the cranks although loctite is a must with only 3 chainring bolts and a screw-on spider.


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## nino (Jan 13, 2004)

*Q-Factor?*

Cheers - what's the Q-factor on your setup?


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## Cheers! (Jun 26, 2006)

with a plastic ruler and me taking the left crank arm off and rotating it 180 degrees so it's above the drive side crank arm... and torquing it back down.

I'm measuring between 16.3 cm to 16.5 cm... sorry that is best I can do with the plastic ruler as the 6" vernier caliper is too small.

If I used the spacer on teh drive side BB cup the non drive side crank arm was about 1 mm away from the left side chainstay, and I could squeeze the arm and the chain stay together with my hand. So it was too close to comfort.


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## supaman03 (Aug 18, 2009)

what BB should i use? Ordering RS8's from crc and not sure about a BB size, how do i know what size?


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## russya (May 3, 2007)

what frame are you using? You may need a 68 or a 73. If you get a Crank Brothers isis bb then that part doesn't matter they do both. You'll be worried about clearance with the chainstay after you figure out the proper width. For light weight you can look at the Token and the American Classic. 

I prefer the Crank Brothers Cyan even though it's a little heavier than the other options, it's bomb proof and is the only one I found that is a 108 and fits a 73 shell. So first step is figuring out wether you need the 68 or 73 and go from there


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## supaman03 (Aug 18, 2009)

I'm running a scott racing comp, same frame and cranks as this: https://www.streek.org/ardennenkings/pictures/scott_comp_racing.jpg

Thanks for the help


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## snowdrifter (Aug 2, 2006)

ISIS = I need new bearings every few months!


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## Cheers! (Jun 26, 2006)

Look here for my difficulty in trying to use a 108mm ISIS BB.

http://forums.mtbr.com/showthread.php?t=493284&highlight=clearance


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## russya (May 3, 2007)

The crank brothers isis bottom bracket are a lot more reliable than the others. Bearings are sealed really well which is why I recommend that one in particular. 

As for clearance, you never really know till you try. 108 fit just fine on my epic, but I have the 40t and 27t so slightly smaller rings than cheers, but my arms cleared easily. I thought for sure with my frame begin FS that I would run into that same problems but that never happened


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## russya (May 3, 2007)

This is what you need to measure first on your frame to know what part you need. Except if you get the Crank Brothers bb. Since they work with both sizes it doesn't matter


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## bholwell (Oct 17, 2007)

Cheers, how's the American Classic BB been holding up for you? I hope you're not ticked, but it looks like I might be getting the same crankset for my M230.


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## Cheers! (Jun 26, 2006)

No issues. Still spins smooth. I've even submerged it in a river crossing. Mind you I have a drain hold on the bottom bracket shell.


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## bholwell (Oct 17, 2007)

Cheers! said:


> No issues. Still spins smooth. I've even submerged it in a river crossing. Mind you I have a drain hold on the bottom bracket shell.


Thanks for the info. The AC BB seems like a no-brainer, then.

It seems like the drain hole on my BB shell is actually a second tapped hole for the plastic cable guide (or whatever you call that thing.)


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## conrad (Jan 27, 2004)

*middleburn are doing 27/40 duo combos*

On their web site they are now listing 27/40 combos:thumbsup: 
I personally have ti 27/40 rings from Mattias on 180 RF turbine LP's. Best combo ever!!!!
ISIS bb's are a problem, as most don't seam to last too long. The SKF 600 series looks good but it is very heavy. Sort of neglates the light weight crank arms/rings. :madman: 
Middleburn will be coming out with an external crankset next year.....I hope it comes in a 180 duo format


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## bholwell (Oct 17, 2007)

conrad said:


> On their web site they are now listing 27/40 combos:thumbsup:
> I personally have ti 27/40 rings from Mattias on 180 RF turbine LP's. Best combo ever!!!!
> ISIS bb's are a problem, as most don't seam to last too long. The SKF 600 series looks good but it is very heavy. Sort of neglates the light weight crank arms/rings. :madman:
> Middleburn will be coming out with an external crankset next year.....I hope it comes in a 180 duo format


Yeah, the 27/40 is the combo I'll be going with. The SKF 600 ISIS BB's look ridiculously heavy. Supposedly the American Classic BB's have replaceable cartridge bearings- I won't mind if I have to replace these once per season. Still very light!

http://www.amclassic.com/products/components/isisbb.php


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## tileman (Nov 1, 2006)

*stiffness.................*

Ok, I'd love a set of these cranks (RS 8), but the stiffness things has me second guessing. I have in the past have a ss Voodoo Azian with front sus and the bike flexed a lot, and I found it un-nerving (i do not claim to be a great rider, but this was the first bike I felt it). From some reviews on RS8's it has not been a question of the cranks being bad, its just that when big riders push the cranks, you apparently could see them flex. I'm all for light, cool looking parts.......

Has anyone found this flex, has anyone moved on from the cranks because of this? Have any riders (of the bigger set) found this flex, and does it worry you?

Any thoughts?


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## Cheers! (Jun 26, 2006)

If your primary concern is stiffness these cranks are not for you. 

You should just buy a set of XTR CS-M970 and call it day. Best stiffness to weight ratio. Probably one of the stiffest mountain bike cranks available. Brilliant shifting.


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## russya (May 3, 2007)

I'm not a small guy, all geared up I'm around 210. The stiffness of these cranks has never been an issue.


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## Tibo971 (Jul 17, 2010)

Hello Cheers, I sent you a PM if you can answer them!


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## conrad (Jan 27, 2004)

*hve got my m980 duo cranks now*

Yes I stumped up for m980 180mm 28/40 cranks, since dropped the 28 for a mattias custom ti 27 ring:thumbsup: 
light, stiff & sweet shifting....with m980 triggers & GS mid cage rear D. 
I'm 6'2" & 95kgs.......so no light weight pounding on my cranks. 
A cheaper option is m770 180mm length set up with duo rings. 26/40 rings. These I have paired with m970 shifters & D's on my everyday training bike. Both run 11-34 cassettes. 
Conrad


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