XTR 2015

Discuss light weight issues concerning mountain bikes & parts.

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ratherbeintobago
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by ratherbeintobago

Electric XTR Di2 would most likely be expensive, hard for the home mechanic to maintain/ fix at the trailside and all without any real clear benefits


I'm not sure about that at all. An awful lot of people in the UK ride within short distances of civilisation (or in trail centres), and cables that can't get clagged up in the mud are quite attractive. Witness how Di2 seems to be flavour of the month in 'cross.

The thing I really object to about 2015 XTR is it looks like they've adapted the offset spider arms from Dura Ace, which means we have another BCD to contend with.

Yeah, the difference between having a 10 tooth vs 11 tooth available is huge!


It's only 10% :-P

wingguy
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by wingguy

Little bit less than 10%. But that's huge. It's close to changing two chainring sizes, and the corresponding benefits at the other end of the range.

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TheRookie
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by TheRookie

Given the gap between gears on most MTB cassettes is circa 12.5% (it's not consistent of course as we are stuck with whole numbers of teeth) it's less than one extra gear (as such). Of course it's not the size of the smallest that matters but the total spread (assuming the largest doesn't end up too big to be practical), so running an 11t smallest you get the same spread by making the largest circa 9% bigger than if you were running a 10t smallest.
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wingguy
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by wingguy

Ok, so how do you do that? According to the details on that leaked brochure Shimano's big cog is 2 teeth smaller than SRAM's big cog. Are you expecting an aftermarket company to bring out an 11-46?

trailgumby
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by trailgumby

The main advantage I see for Di2 XTR is in foul weather, so long as it's immersion proof.

The biggest single problem with half and full marathon events in muddy conditions is losung control of your drivetrain because of mud contamination.

I resolved that by using Gore Ride On sealed cables but now that Gore in their wisdom (bless them) decided to cease selling them except through SRAM they have been difficult to find locally. Most racers would just put up with diabolical drive trains.

Di2 resolves that nicely.

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hjb1000
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by hjb1000

So am I reading this right that XTR 2015 will have an 11-speed HG freehub like the 11-speed Shimano road? So obviously no 10T sprocket... :)
Also do we have a release date yet?

DanW
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by DanW

The main advantage I see for Di2 XTR is in foul weather, so long as it's immersion proof.

The biggest single problem with half and full marathon events in muddy conditions is losing control of your drivetrain because of mud contamination.

I resolved that by using Gore Ride On sealed cables but now that Gore in their wisdom (bless them) decided to cease selling them except through SRAM they have been difficult to find locally. Most racers would just put up with diabolical drive trains.

Di2 resolves that nicely.


It's a big assumption and hope that Di2 nicely resolves mud and water issues with cables etc.... just ask Wiggins after his infamous bike toss last year and several other high profile failures in road races featuring rain.

No issues with cables and a sh1t ton of mud here in the UK with XX1 :D The chain being absolutely covered in mud and starting to grind everything mid ride is a far bigger issue for me and not solved by Di2. What I don't like about XX1 is that it is made with SRAm materials and quality. Give me a Shimano version and I'm happy :thumbup:

jooo
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by jooo

@DanW - To counter your example (Wiggins), Di2 has been extremely well proven in CX, lots mud and frequent power washing...

Ypsylon
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by Ypsylon

I've been on Shimano Dynasys for a limited amount of time only, but I was extremely impressed with the front shifting. I can see why they think they don't have to get rid of it.

I'm not sure if 2x11 doesn't give you more options and a less severe chainline most of the time. I'm not a huge fan of the 10 teeth sprocket (in theory, at least) and on of my buddies claims he can feel the difference between the weight distribution as he changed from 2x10 to 1x11, with the lighter crank and heavier cassette.

I'm not sure if I should call BS on that one, but the cassette with the 42 teeth is pretty heavy and it's unsprung mass and stuff.

So far it's all in my head, but I'm curious about this one and will try my best to find a test ride.
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DanW
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by DanW

Feeling different weight distribution is BS IMO but the chainline is my only real criticism of XX1. At the extreme ends of the cassette the chainline is really being challenged. Pedaling does not feel smooth especially in the granny until the chain ring wears a little to accomodate the severe angle of the chain IME. I'm not convinced that 2x11 hold any advantages over 2x10 but it would be daft for Shimano not to make updates if going the whole hog with Di2 XTR I suppose.

wingguy
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by wingguy

Ypsylon wrote:...one of my buddies claims he can feel the difference between the weight distribution as he changed from 2x10 to 1x11, with the lighter crank and heavier cassette.

I'm not sure if I should call BS on that one, but the cassette with the 42 teeth is pretty heavy and it's unsprung mass and stuff.


Of course you should call BS on it. It's 50g. Tape a couple of AA batteries to his seatstay when he's not looking and see if he can feel it.

bm0p700f
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by bm0p700f

10T rear sprocket is pointless it will wear out too quickly. I ride in the U.K and use a double. Most people I see at races still use doubles the other half use single chainrings. Triples are non existant except on my retro's. I cannot see the issue with trimming but then again I have a thumb shifter for the front chainring, problem solved.

I prefer 12T start cassette's but that means road cassettes. I hardly ever use 40/11 40:12t would be fine even in races. But you can't buy a 12T 11 speed cassette from shimano, Miche do one but that is a fair bit heavier.

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743power
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by 743power

Bm0- shimano does 12-25 in cs6800 and cs9000 and 12-28 in cs9000
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bm0p700f
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by bm0p700f

They do but I can't climb alot of the hills in the race courses I do o 28:25T I have enough trouble on 28:28T. Have you done the olympic park course I have (MSG round 8) it scared me half to death but one of the hills is far too steep for 28:25T. I am not switching my rings to 38:26T as I need the 40:12T ratio to keep the pace up on straights.

jimborello
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by jimborello

A friend of mine saw it in Taipei and he says they are coming out with a 2x11 electronic groupset, no 10t cog. I guess they dont feel a 1x11 is wide enough for mtb use

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