CT 1x11 crankset - have I been sent the correct item?

[tjdixon911]

Just received my new crankset today, ordered a 1x11 XT item, the box is marked as 1x11 (has tick boxes for 2x, 3x etc.

The crankset has 2 sets of bolt holes for the chain rings, I.e a main chain ring and granny ring as below, is this correct or have I got the wrong item?

[gazza285]

1x or 2x, choice is yours. It's probably not worth the retooling to make a single ring spider.

[tjdixon911]

I was thinking as long as the chain line is correct then I may as well keep it - it gives me the option of running a 2x at a later date - just confused as to why, if it is correct they mark the box and sell them as a 1x set (I purchased cranks only without chainrings)

[paulmon]

Different chainlines for different cranksets on the new XT range. The single has a 50mm whilst the double is 48.8 unless you have a boost hub in which case its 52ish. Personally if I'd bought this new I would be sending it back because they are different and if you ever want to sell it you will only be able to sell it as a 2x or 3x.

[tjdixon911]

paulmon said:

Different chainlines for different cranksets on the new XT range. The single has a 50mm whilst the double is 48.8 unless you have a boost hub in which case its 52ish. Personally if I'd bought this new I would be sending it back because they are different and if you ever want to sell it you will only be able to sell it as a 2x or 3x.

Thanks that's what I needed to know.

I will get it returned and replaced.

(just noticed the thread title should be XT not CT)

[gazza285]

See here.

http://www.bikeradar.com/mtb/news/article/shimano-...

Same chainset for single and double...

[tjdixon911]

gazza285 said:

See here.

http://www.bikeradar.com/mtb/news/article/shimano-...

Same chainset for single and double...

bikeradar said:

"Just like XTR, XT M8000 will continue to allow options, with 1x11, 2x11 and 3x11 drivetrain configurations available. The standard crankset is the same for both 1x and 2x setups, although it’s to be confirmed if the 3x crank is different again."

That confuses things but how does the double and single have different Chain Lines? 50 & 48.8 as paulmon says above? is this changed with the different chain ring?

Also, the box has various tick options for content, these being along the lines of 1x w/o cranks, 2x w/o cranks and 3x etc.

[paulmon]

gazza285 said:

1x or 2x, choice is yours. It's probably not worth the retooling to make a single ring spider.

Looks like this is correct. Looking around it looks like you can only buy the crank arms (no rings) as a 1x11 setup which has the correct chainline.

http://www.jensonusa.com/Shimano-XT-FC-M8000-Singl...

[gazza285]

You can adjust the chain line either out using bottom bracket spacers, or in using chainring spacers. I wonder if the single and double chainrings have different offsets to compensate.

[tjdixon911]

paulmon said:

gazza285 said:

1x or 2x, choice is yours. It's probably not worth the retooling to make a single ring spider.

Looks like this is correct. Looking around it looks like you can only buy the crank arms (no rings) as a 1x11 setup which has the correct chainline.

http://www.jensonusa.com/Shimano-XT-FC-M8000-Singl...

That's the first ad I've seen with the inner part of the spider pictured, looks like I do have the correct ones on that basis.

I did send the image to Shimano via FB so will see what response I get there.

As I did a click and collect, the store (Evans) are getting another set in to swap over but I'll have them check before making the trip across town...

[paulmon]

gazza285 said:

You can adjust the chain line either out using bottom bracket spacers, or in using chainring spacers. I wonder if the single and double chainrings have different offsets to compensate.

I think its the spider that has the offsets because the same chainrings with the same part numbers are available for all three chainlines.

[tjdixon911]

paulmon said:

gazza285 said:

You can adjust the chain line either out using bottom bracket spacers, or in using chainring spacers. I wonder if the single and double chainrings have different offsets to compensate.

I think its the spider that has the offsets because the same chainrings with the same part numbers are available for all three chainlines.

The single ring will be different to any 2x or 3x as the single has the narrow wide (Shimanos equivalent) teeth.

I've had a response from Shimano, the unit is correct and the chainline figures are different because of the different offsets on the chainrings essentially - the message said he could give me all the technical details as to why but it would be a long message!