Spline compatibility on Shimano two-piece cranks

All,

My question is: among the various Shimano two-piece cranks - the ones
with spindle and right-side permanently connected - is there
inter-compatibility of the left-side arms at the spindle spline?

**leaving aside issues of Q factor, chainstay clearance, etc** - I just
want to know if it is possible to safely attach, say, a GRX left arm on
a 105 crank? Are the current Shimano splines all the same?

Reason: I'm looking to retrofit my gravel bike with a GRX RX-600 crank,
available in 30/46, which fits my needs.
But I'd also like to consider a Stages power meter, only available with
*other* left arms, e.g. a GRX RX-800 (whole crank only available in
31-48, not quite what I wanted) or an Ultegra or 105.

Chainstay clearance, esp. with the Stages pod attached, will definitely
be an issue, just want to know if the arm will even attach at all.

Mark J.

On Monday, January 25, 2021 at 12:43:13 PM UTC-8, Mark J. wrote:
All,

My question is: among the various Shimano two-piece cranks - the ones
with spindle and right-side permanently connected - is there
inter-compatibility of the left-side arms at the spindle spline?

**leaving aside issues of Q factor, chainstay clearance, etc** - I just
want to know if it is possible to safely attach, say, a GRX left arm on
a 105 crank? Are the current Shimano splines all the same?

Reason: I'm looking to retrofit my gravel bike with a GRX RX-600 crank,
available in 30/46, which fits my needs.
But I'd also like to consider a Stages power meter, only available with
*other* left arms, e.g. a GRX RX-800 (whole crank only available in
31-48, not quite what I wanted) or an Ultegra or 105.

Chainstay clearance, esp. with the Stages pod attached, will definitely
be an issue, just want to know if the arm will even attach at all.

Mark J.

From Stages: https://tinyurl.com/y52quveo

Shimano Hollowtech II

While we offer current model left crank options for Dura-Ace, Ultegra, and 105, additional component levels and many older groups are also compatible. Shimano road cranks are interchangeable between other component levels that utilize the dual pinch bolt. Nearly all pinch-bolt style Shimano road cranks are able to be interchanged in equivalent lengths. Stages Power R right-side Shimano road power meters can also be used with any Hollowtech II compatible left crank arm.

For Shimano Hollowtech II mountain bike cranks, only XT and lower cranks are interchangeable. XTR cranks must be matched up with the equivalent XTR left crank model in either the "race" or "trail" style. Road and mountain bike cranks are not able to be interchanged due to the extreme difference in offset.

Other Questions?

If you're still unclear if your existing crank will work, please open up a support ticket with Stages Cycling or Stages Cycling Europe including information regarding your current cranks.

----------------------

My understanding is that GRX is compatible with any HT2 road crank arms. e..g. https://www.trainerroad.com/forum/t/...tibility/19369

My son did customer service at Stages for over a year before going to Specialized, and he was a real responsive guy -- so I'd bet customer service is still responsive. E-mail them a question.

Fun fact -- my son smashed both ankles in a skiing accident on Christmas eve while visiting three years ago. He ended up moving in with us post surgery and giving up his place in Salt Lake -- and his job. He interviewed at Stages in a wheelchair with both legs in casts. He got the job and worked his first few months in a wheelchair. They were really good to him -- so support Stages!

-- Jay Beattie.

On 1/25/2021 1:25 PM, jbeattie wrote:
On Monday, January 25, 2021 at 12:43:13 PM UTC-8, Mark J. wrote:
All,

My question is: among the various Shimano two-piece cranks - the ones
with spindle and right-side permanently connected - is there
inter-compatibility of the left-side arms at the spindle spline?

**leaving aside issues of Q factor, chainstay clearance, etc** - I just
want to know if it is possible to safely attach, say, a GRX left arm on
a 105 crank? Are the current Shimano splines all the same?

Reason: I'm looking to retrofit my gravel bike with a GRX RX-600 crank,
available in 30/46, which fits my needs.
But I'd also like to consider a Stages power meter, only available with
*other* left arms, e.g. a GRX RX-800 (whole crank only available in
31-48, not quite what I wanted) or an Ultegra or 105.

Chainstay clearance, esp. with the Stages pod attached, will definitely
be an issue, just want to know if the arm will even attach at all.

Mark J.

From Stages: https://tinyurl.com/y52quveo

Shimano Hollowtech II

While we offer current model left crank options for Dura-Ace, Ultegra, and 105, additional component levels and many older groups are also compatible. Shimano road cranks are interchangeable between other component levels that utilize the dual pinch bolt. Nearly all pinch-bolt style Shimano road cranks are able to be interchanged in equivalent lengths. Stages Power R right-side Shimano road power meters can also be used with any Hollowtech II compatible left crank arm.

For Shimano Hollowtech II mountain bike cranks, only XT and lower cranks are interchangeable. XTR cranks must be matched up with the equivalent XTR left crank model in either the "race" or "trail" style. Road and mountain bike cranks are not able to be interchanged due to the extreme difference in offset.

Other Questions?

If you're still unclear if your existing crank will work, please open up a support ticket with Stages Cycling or Stages Cycling Europe including information regarding your current cranks.

----------------------

My understanding is that GRX is compatible with any HT2 road crank arms. e.g. https://www.trainerroad.com/forum/t/...tibility/19369

My son did customer service at Stages for over a year before going to Specialized, and he was a real responsive guy -- so I'd bet customer service is still responsive. E-mail them a question.

Fun fact -- my son smashed both ankles in a skiing accident on Christmas eve while visiting three years ago. He ended up moving in with us post surgery and giving up his place in Salt Lake -- and his job. He interviewed at Stages in a wheelchair with both legs in casts. He got the job and worked his first few months in a wheelchair. They were really good to him -- so support Stages!

-- Jay Beattie.

Thanks, Jay, that's very helpful.

Mark J.

On Monday, January 25, 2021 at 1:30:03 PM UTC-8, Mark J. wrote:
On 1/25/2021 1:25 PM, jbeattie wrote:
On Monday, January 25, 2021 at 12:43:13 PM UTC-8, Mark J. wrote:
All,

My question is: among the various Shimano two-piece cranks - the ones
with spindle and right-side permanently connected - is there
inter-compatibility of the left-side arms at the spindle spline?

**leaving aside issues of Q factor, chainstay clearance, etc** - I just
want to know if it is possible to safely attach, say, a GRX left arm on
a 105 crank? Are the current Shimano splines all the same?

Reason: I'm looking to retrofit my gravel bike with a GRX RX-600 crank,
available in 30/46, which fits my needs.
But I'd also like to consider a Stages power meter, only available with
*other* left arms, e.g. a GRX RX-800 (whole crank only available in
31-48, not quite what I wanted) or an Ultegra or 105.

Chainstay clearance, esp. with the Stages pod attached, will definitely
be an issue, just want to know if the arm will even attach at all.

Mark J.

From Stages: https://tinyurl.com/y52quveo

Shimano Hollowtech II

While we offer current model left crank options for Dura-Ace, Ultegra, and 105, additional component levels and many older groups are also compatible. Shimano road cranks are interchangeable between other component levels that utilize the dual pinch bolt. Nearly all pinch-bolt style Shimano road cranks are able to be interchanged in equivalent lengths. Stages Power R right-side Shimano road power meters can also be used with any Hollowtech II compatible left crank arm.

For Shimano Hollowtech II mountain bike cranks, only XT and lower cranks are interchangeable. XTR cranks must be matched up with the equivalent XTR left crank model in either the "race" or "trail" style. Road and mountain bike cranks are not able to be interchanged due to the extreme difference in offset.

Other Questions?

If you're still unclear if your existing crank will work, please open up a support ticket with Stages Cycling or Stages Cycling Europe including information regarding your current cranks.

----------------------

My understanding is that GRX is compatible with any HT2 road crank arms.. e.g. https://www.trainerroad.com/forum/t/...tibility/19369

My son did customer service at Stages for over a year before going to Specialized, and he was a real responsive guy -- so I'd bet customer service is still responsive. E-mail them a question.

Fun fact -- my son smashed both ankles in a skiing accident on Christmas eve while visiting three years ago. He ended up moving in with us post surgery and giving up his place in Salt Lake -- and his job. He interviewed at Stages in a wheelchair with both legs in casts. He got the job and worked his first few months in a wheelchair. They were really good to him -- so support Stages!

-- Jay Beattie.
Thanks, Jay, that's very helpful.

All of the upper end Shimano cranksets that are made in Japan are interchangeable as far as I can remember.