[Closed] Converting XTR cranks to double 9x2 what do i need to do?

http://clee-cycles.co.uk/cc/catalog/product_info.php/cPath/24_34/products_id/481?osCsid=0503df51b92cad81ed28e5ca8bf6e25e

short bolts, thats all

If it's M970's you will need:

- Tools (25 and 30 torx for the rings unless I remember incorrectly, Shimano special tools to get the left crank arm off)
- The new chainrings
- Bash Ring
- Either shorter bolts for the bigger ring / bash or spacers for under the bolt

And then maybe a chain tool to shorten the chain a bit if you feel like it.

That's exactly what I have. Bashring not needed.

Shorter chainring bolts for the middle ring (singlespeed chainring bolts)

If you're changing the granny ring (and I assume you will since XTR is 22 as standard), you'll need four 2mm washers to space out the granny ring from the cranks (the XTR ring has this built into it).

It's M970 so from above i gather i need:

1. New rings (any preferred choices out there keeping black theme?)
2. The bolts from KCNC that dirtyrider sent and gather i do not need washers to space out as XTR has these built in?

I have the tools to get the crank off and in peices, just putting everything together that i need to make sure i have.

XTR has the washers built into the granny ring. If you fit a non-shimano XTR granny ring then you'll need the 2mm washers/spacers.

Also do i need to change my front mech? or just adjust the low, highb and tension?

Looking at these for 36 ring maybe just keep my XTR 22 for bailout instead of going for 24?
http://www.leisurelakesbikes.com/product/mrppodiumchainringset.aspx?&id=11744

I found that swapping to a double specific mech worked much better - stopped the chain dropping - mine's an SLX

on both my bikes ive found that the standard front mech works perfectly.

adjust the top limit screw to prevent overshifting and possibly move the mech downwards on the seatpost a touch.

used a normal 3 ring mech but move it up, so that the middle section lines up with the 36T ring.

Thanks for advice people. Gonna go for MRP 36 front chainring, keep XTR 22 as a bail out option and swop to a double specific front mech, maybe even a road one SRAM Force/Dura Ace or opt for SLX as clubber said.

Hell of a lot easier to go for a 1x9 isn;t it! New MRP 1 guide http://www.leisurelakesbikes.com/product/mrp1xchaindevice.aspx?&id=12658 and 36 chainring. hmmmmmm could the legs cope?????

personally, i dont think i could manage with a single 36

maybe if i got one of them girly cassettes with a 34t sprocket, also possibly if i dropped down to a 34t chainring, 32t chainring doesnt give me a big enough gear for the majority of my rides.

2x9 for now.

A road mech will shift worse than an MTB triple one, and I'm not convinced of the real benefits of the SLX double, I certainly wouldn't replace a perfectly good triple mech.

TA Chinook rings are good as an alternative, likely to be lighter than the MRP ones.

XTR triple lost the chain all the time, swapped to an SLX double and never had a problem again. Worked for me 😉

Fair enough, never had a problem with XTR triples in 3 years myself!

Just to hijack, I use mine with an XTR triple and occasionally on rocky descents it drops the chain from the big ring onto the crank arm, any ideas? Should I lower the mech or adjust the limit screw?

I'd see if you need to lower the mech first, it should be 2mm above the big ring, although you may need to tweak your stop screw too!

I'd like to keep my xtr triple of course, may play around and if it does drop it consider slx. They use SRAM force for Paris roubaix that's why I thought to keep it as an option?

I like the chunky look of the mrp 36 ring

cheers

Njee - you run bigger rings so it's less of an issue for you.

See I always thought you should keep the mech at the original height ie for a 44T, I'll lower it a little and see what happens.

I just did the SDW on a Stumpy with 3 x 9 and used everything from 22-34 to 44-11. There are some quite fast road sections I needed the big ring for and I was on the granny and 34t rear going up Butser Hill (from the Eastbourne end) in 25 degree heat.

Njee- what rings are u running then?

Njee - you run bigger rings so it's less of an issue for you.

Fair point actually! I'll be quiet.

Edit: when I had 9 speed I was running 28/40 and 11-34, for me that was more than enough, but that was on a light XC race bike.

Shedful - as always, the question is how much would you really lose by losing the top couple of gears. Long DH sections on road will clearly spin out on a 36x11 but how much time do you lose through not pedalling? a minute? Even that may well be overstating it for most people unless they're descending proper mountains since if you're really needing 44x11 it must be a pretty big hill meaning high speed and less benefit (since drag goes up exponentially) of being able to actually push the bigger gear.

Unless you're racing seriously or really like to grind big gears, it makes very little real difference.

Shedful. Thanks for that background on gearing as SDW is on my cards so I think even more a 36 22 set up is spot and means I only have to fork out for one new chainring.