Di2 10spd compatibility with 11spd crank

[grappa larks]

Currently running D-A 7970 Di2 53-39 with 12-30 on rear cassette. It's mountainous here with significant long ramps of 12-15%.
I have a D-A 12-28 cassette waiting to be used.
The dinner plate 30 feels a little out of bounds, sometimes.

Has anyone mixed an 11spd crank (da9000) with 7970 10spd drivetrain?

Previously I found the compact option span out on long descents, so considering a change is coming has anyone experience with using a 52-36, and was stiffness lost with a smaller BB?

Has anyone tried the praxis 52-36 option?

Is it advisable to stick with a 10spd setup throughout and get a compact +11-25/7 cassette? What would the perceived difference be?

Advice welcomed. Thanks

 

[Bustedknuckle]

Currently running D-A 7970 Di2 53-39 with 12-30 on rear cassette. It's mountainous here with significant long ramps of 12-15%.
I have a D-A 12-28 cassette waiting to be used.
The dinner plate 30 feels a little out of bounds, sometimes.

Has anyone mixed an 11spd crank (da9000) with 7970 10spd drivetrain?

Previously I found the compact option span out on long descents, so considering a change is coming has anyone experience with using a 52-36, and was stiffness lost with a smaller BB?

Has anyone tried the praxis 52-36 option?

Is it advisable to stick with a 10spd setup throughout and get a 11-25/7 cassette? What would the perceived difference be?

Advice welcomed. Thanks

Unlike a 10s crank onto an 11s system, a 11s crank works just fine with a Di2, 10s setup. You cannot tell stiffness difference..becsides, 7900 and 9000 cranks/chainrings are stiff specifically for Di2.

Stay away from praxis..poor chainrings by comparison.

Perception is exactly that, personal...

 

[grappa larks]

Thanks for reply BustedKnuckles.

If there is no real (or perceived )difference then I am grateful that others have tried options contrary to Shimano official advice.

So have you tried this setup yourself, or know others who have? Moreover has the setup been proven over a reasonable amount of miles and under stress?

I note that 11spd and 10spd chains are different widths, but I think I the difference is not on the internal width. So am I right to conclude that, in this case, a standard 10spd chain runs smoothly?

Praxis cold forge also, and I guess they have their measurements calculated to many decimal places, I suppose they hack out the shape pretty accurately. Anyway, that was a little frivolous to arrive at the request for precise reasons regarding the inferiority of praxis, in this case. Is there skipping, flex, unreasonable wear?

We get what we pay for, and I don't want to hedge away from praxis without good reason.

Ta

 

[Bustedknuckle]

Thanks for reply BustedKnuckles.

If there is no real (or perceived )difference then I am grateful that others have tried options contrary to Shimano official advice.

So have you tried this setup yourself, or know others who have? Moreover has the setup been proven over a reasonable amount of miles and under stress?

I note that 11spd and 10spd chains are different widths, but I think I the difference is not on the internal width. So am I right to conclude that, in this case, a standard 10spd chain runs smoothly?

Praxis cold forge also, and I guess they have their measurements calculated to many decimal places, I suppose they hack out the shape pretty accurately. Anyway, that was a little frivolous to arrive at the request for precise reasons regarding the inferiority of praxis, in this case. Is there skipping, flex, unreasonable wear?

We get what we pay for, and I don't want to hedge away from praxis without good reason.

Ta

I owned a bike shop and have put many 11s cranks onto 10 systems, both mechanical and electronic. A 10s chain will work fine. The rings are closer on 11s but you can adjust the limits to work fine on a 10s system.

I have also put other than shimano, 11s cranks onto Di2 and EPS..and the shimano or Campagnolo cranks are just better, in terms of CR longevity, BB reliability..overall quality. Praxis, in spite of their copy, don't shift as well as shimano cranks/CRs, IMHO.

 

[grappa larks]

Thanks busted. I'll give it a go and report back in a few thousand km, with special attention paid to chain wear, audible differences, shifting fluidity.

In the meantime if anyone has used this option under stress for a significant period of time a report would be helpful for the community.

Cheers

 

[Fat former racer]

I've been running Di2 7900 53/39 cranks with a 12-28 cassette without any problems. Just like you, the terrain around here is brutal so I swapped the DA crankset over to an 11-spd Ultegra 6800 compact 50/34. Not one problem. Other than lowering the front derailleur, I didn't make any adjustments. The compact helped a lot last fall when I was really struggling up some of the climbs around here but I've improved enough to switch back to the DA 53/39. Again, the DA crank is 7900 10-spd and didn't require any adjusting of the shifters.