Raceface Cinch Spindle

[Traveler]

Been looking to take the plunge on a power meter. Being MTB, you are basically limited to the RF Cinch, Quarq-D or Rotor INpower. All the others have proven themselves very unreliable on MTB's, and then you have the vibration effect which just destroys accuracy. No matter what the manufacturers claim, real world tests all yield the same results.

 

So..... Out of that list, the Cinch Spindle looked like a nice option, but I am not yet ready to chuck my SRAM BB30 Crank, as I need 170mm crank arms, and RF only makes as short as 172.5mm crank arms.

 

After some further research, it is possible to fit a Cinch spindle to a carbon SRAM crank. Below is a picture of a test fit of a standard Cinch spindle which I borrowed to test the theory. I tried to take the attached picture to show it really is an RF spindle on a SRAM Crank.

 

Has any Hubbers yet gone this route of fitting a Cinch PM to SRAM crank arms?

[NicoR]

Plenty admin for 2.5mm difference

[Traveler]

Plenty admin for 2.5mm difference

 

Friday sarcasm.....

 

If you include the RF arms it moves the price from R8k for the spindle to R12k for the complete set.... Let alone the R460 per week for the treatment of my sciatic nerve.

[BikeisLife]

Are cinch PM spindles available locally yet? Last I heard they were still trying to obtain safety documents from RF for approval from ICASA...

[Traveler]

Are cinch PM spindles available locally yet? Last I heard they were still trying to obtain safety documents from RF for approval from ICASA...

 

They are available now. The first shipments arrived about a week or 2 ago.

 

That is how I managed to get my hands on the non PM version of a Cinch spindle, as 2 friends received their PM spindles mid last week and are already using them.

 

They however went the whole hog, and they bought the NEXT SL arms also.

[NicoR]

Friday sarcasm.....

 

If you include the RF arms it moves the price from R8k for the spindle to R12k for the complete set.... Let alone the R460 per week for the treatment of my sciatic nerve.

Apologies. First thing that came to mind...

[MTB-More]

Awesome. Friday thread found. 

 

I personally think if your legs can feel a 2.5mm difference you should sign up for testing with NASA. In all fairness when I went from 170 to 175mm on crank arm length it felt a lot better and more natural for me.

 

If it really is a issue get XTR Shimano pedals as they are 3mm thinner than the M520 and XT pedals that should balance out the difference. 

[Spoke101]

In theory it should be possible.

 

Just check all the friction fit dimensions and bolt threads. Other than that spindle length can be compensated for if a bit longer.

[JA-Q001]

Awesome. Friday thread found. 

 

I personally think if your legs can feel a 2.5mm difference you should sign up for testing with NASA. In all fairness when I went from 170 to 175mm on crank arm length it felt a lot better and more natural for me.

 

If it really is a issue get XTR Shimano pedals as they are 3mm thinner than the M520 and XT pedals that should balance out the difference. 

 

Sorry, not personal, but first you contradict yourself by saying its strange if he feels a difference, but then saying it was better for you when changing.

 

And then pedals stack height works differently than crank arm length. Stack height keeps pedal circle diameter the same, but lifts your saddle, crank arm length changes your pedal circle diameter.

[Traveler]

Awesome. Friday thread found. 

 

I personally think if your legs can feel a 2.5mm difference you should sign up for testing with NASA. In all fairness when I went from 170 to 175mm on crank arm length it felt a lot better and more natural for me.

 

If it really is a issue get XTR Shimano pedals as they are 3mm thinner than the M520 and XT pedals that should balance out the difference. 

 

Ok, here we go again that crank arm lengths is pointless.....   

 

Sounds like the reason why most bike fitment "specialists" in South Africa ignores crank lengths when they do bike fitments. "Your legs will not know the difference in a 5mm, lets us just drop or raise your saddle...."

 

What is the average intervertebral disc space in your back? For the average male of 1.8m tall it should be around 9.19mm. As you age the intervertebral disc space starts to reduce as well. Therefore if you increase the sideways tilt due to cranks which are too long and you deal with 2.5mm either way, it is 2.5mm + 2.5mm, this places at least 5mm sideways movement on your. Intervertebral disc space, that is more than half the available space which is now consistently compressed from side to side.

 

A thinner pedal will have a lower stack height.... lower stack height increases the distance from the saddle to the bottom of the pedal stroke.... So, now I decrease stack height by 3mm on each side.... starting to get the picture. There is a whole science behind correct crank lengths, we just ignore the facts because all our bikes come standard with a 175mm XT Crank, that ain't because 175mm is the ideal crank lengths, that is because it makes the purchase arrangement the easiest for the bike manufacturer and the component suppliers.

 

After years of trouble with my back (resulting from a hit and run), I am not going to take another chance, 170mm cranks are what I am riding with.

[Traveler]

In theory it should be possible.

 

Just check all the friction fit dimensions and bolt threads. Other than that spindle length can be compensated for if a bit longer.

 

Thanks for a constructive response to the actual question....         

 

Bolt thread pitch is identical for the two (if you want to use the SRAM bolt). Measured that with a pitch gauge before I even tried.

 

The friction fit is the only part which I am not certain about, one might need to take all to an engineering company that can measure by laser to ensure exact/identical dimension in that perspective.

[sirmoun10goat]

I had a RF Cinch on my Stumpy HT - the crank kept turning lose. My bike shop replaced the crank and spindle - same issue. It was then replaced with a Sram GX crank - no problems since then.

 

For some reason the Cinch just did not want to work on my bike, whereas the Sram did. Not saying there will be compatibility issues, but there must be some difference between the RF and Sram spindles

[Spoke101]

Thanks for a constructive response to the actual question....         

 

Bolt thread pitch is identical for the two (if you want to use the SRAM bolt). Measured that with a pitch gauge before I even tried.

 

The friction fit is the only part which I am not certain about, one might need to take all to an engineering company that can measure by laser to ensure exact/identical dimension in that perspective.

 

Without having both in my hands I can't give you my guess as to whether it will work. I have done my fair share of Frankenstein component matches through the years.

 

I do know that the BB30 Stages crank arms come with a new blue spindle that you have to install and if memory serves it's made by FSA or FSA compatible.

[JA-Q001]

I have also fitted a cannondale hollowgram axle into a sram BB30 crank. No problems with interface. It would seem that almost all current BB30 spindles have adopted the same interface, which is great, but strange. The sram axles have the problem that the alignment of the splines are different at the left and right, where all others have it the same orientation on both sides. This is to make the FSA used left crank (for stages) compatible with the other BB30 cranks. I know of other people using the Raceface axle in order to space the cannondale cranks better on frankenbites, so I would believe that that axle should work.

 

Just make sure of one thing. The sram left crank does not support a self extracting nut, it has a hard stop. The INPOWER crank orientates the battery cap top the left crank. This could bean that the hard stop would not allow the axle to slot into the crank correctly. Maye you can attach it with battery to the right crank (drive side), but you would then need to change the rotation direction of the power calculation, something that I am not sure if you are able to do in the ROTOR app for the INPOWER.

[Traveler]

I have also fitted a cannondale hollowgram axle into a sram BB30 crank. No problems with interface. It would seem that almost all current BB30 spindles have adopted the same interface, which is great, but strange. The sram axles have the problem that the alignment of the splines are different at the left and right, where all others have it the same orientation on both sides. This is to make the FSA used left crank (for stages) compatible with the other BB30 cranks. I know of other people using the Raceface axle in order to space the cannondale cranks better on frankenbites, so I would believe that that axle should work.

 

Just make sure of one thing. The sram left crank does not support a self extracting nut, it has a hard stop. The INPOWER crank orientates the battery cap top the left crank. This could bean that the hard stop would not allow the axle to slot into the crank correctly. Maye you can attach it with battery to the right crank (drive side), but you would then need to change the rotation direction of the power calculation, something that I am not sure if you are able to do in the ROTOR app for the INPOWER.

 

Awesome thanks!!  

[OnTheRicky]

For the life of me I don't know what I need to read up on to understand if this will fit my crankset or if that's even how this works. 

Could someone please educate me 

 

I've got a Sram GX Eagle DUB Boost crankset.

Will the Cinch work with this, if not, what are my options?