Canondale SI/Rotor SRM in an English threaded BB?

[Wayne77]

Hi,

My frame has an English threaded BB, currently using a Chorus 11sp crank. I'd like to see if I can get this Canondale/Rotor SRM to work. Sounds like something like this would fit the bill? --> http://www.rotorbikeusa.com/products/bsa_bottom_bracket.html

https://farm9.staticflickr.com/8626/16297834440_e341943158_b_d.jpg

[jdp211]

No, that won't work. The Cannondale (road) spindle isn't long enough for an English frame + BSA30, and the SRM spider extends slightly closer to the frame than one without a PM. I've heard of people using a mountain spindle and machining the lip off of it, but then you're left with a very wide q-factor. The BSA30 will work with a Rotor 3d+, and the SRAM BB/PF30 cranks (I run this combo on my Skeletor).

[Wayne77]

Thanks for the info. I'm not positive it has a Canondale spindle...is it possible that these Canondale SRM cranks had regular Rotor spindles? (in which case I assume the adaptor link I including in my OP would work). Or maybe they all had Canondale spindles? -in which case I'm probably out of luck...

[kramnnim]

Don't think a Rotor spindle would fit, and you'd still have the same problem of wide Q factor.

Is it a wired SRM?

[velomonkey]

Yea, can't see how that is gonna work, best I know it's the same spindle, but the Q factor on those cranks are really tight (which I like) and even with another spindle I don't see it working.

[Wayne77]

Thanks guys..I was hoping this would work, but I'm not surprised to hear that it won't. I'll look at some other options to get power measurement on my bike.

kramnnim - yes, that's a wired SRM. This is a unit I could potentially borrow for the season, but it doesn't look like it will work.

-I'll look at some other cost effective alternatives, Garmin Vector, Powertap, iBike, etc

[jdp211]

Not a rotor spindle, the SRM does have a unique spindle and bearing shield (made by Cannondale), but without pretty extensive work it won't mate. If you check out the Weight Weenies board, it's been discussed pretty extensively.


Sent from my spacephone

[kramnnim]

You should probably buy a new frame with a BB30 shell so you can use the crank. :hello:

I hate Hollowgrams for this reason. They're so nice and light, and I spent a bunch of money on one with a Quarq spider...but I'm stuck with BB30 frames now. :mad:

(First world problems, etc)

Oh...and used Quarqs are really cheap now. Used Powertaps even cheaper. iBikes do not seem to be on the same level...at all.

[Auk]

If I recall, the Cannondale/SRM has a slightly longer spindle as it is. I bought one inthe past and it came with two different spindles if you decided to remove the SRM spider and use the standard Cannondale spider.

[Wayne77]

If I recall, the Cannondale/SRM has a slightly longer spindle as it is. I bought one inthe past and it came with two different spindles if you decided to remove the SRM spider and use the standard Cannondale spider.

It would make my day if there is a longer axle that will work. I have one axle on hand - is there a way to tell whether the one I have is the right length? A specific measurement?

This one measures, as near as I can tell, a hair under 10.5 cm

Next question I guess would be whether these longer axles can be purchased somewhere...

https://farm8.staticflickr.com/7460/16471427116_1e0a6afc4e_c_d.jpg

[Look585]

The newest Hollowgram road cranks use a 109mm bb with no shoulder on the non drive side. It *might* have enough room to work.

http://www.cannondaleexperts.com/Cannondale-Hollowgram-SiSL2-109mm-Road-Spindle--KP250_p_2016.html

[kramnnim]

Even if you use a spindle meant for a triple MTB...your chainline is going to be shifted to the right the width of the Rotor BSA30 cup. At least...8mm? 12mm?

[Wayne77]

Even if you use a spindle meant for a triple MTB...your chainline is going to be shifted to the right the width of the Rotor BSA30 cup. At least...8mm? 12mm?

Thanks, I really appreciate your thoughts on this. It's crazy that a crank like this even causes one to ponder the question of getting a bike to fit it :rolleyes:

[jdp211]

Here's the discussion from WW with some detail on how you could make it work. Definitely an involved process and some major sacrifices as far as chainline and Q-factor weightweenies.starbike.com/forum/viewtopic.php?f=3&t=80636