Cannondale SRM differences?

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itsacarr
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by itsacarr

I had heard there was no difference between the SRM hardware but does anyone have any more information on why the difference between last year and this year (the spiders)?

http://www.srm.de/components/com_virtue ... 0265f6.jpg

http://www.bikeradar.com/gallery/articl ... %2Farticle
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ms6073
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by ms6073

I cannot say for certain but I do know that the newer SRM Hollowgram has a bevelled edge at the center hole on the back cover for compatibility with PressFit30 (PF30) framesets. If the back cover of your Hollogram SRM does not have a bevel at the center hole and the cover is held on by slotted screws around the perimeter of the cover, that model will likely be problematic if attempting to fit on a PF30 frameset like a Cannondale SuperSix EVO or 12' Ridley's.
- Michael
"People should stop expecting normal from me... seriously, we all know it's never going to happen"

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itsacarr
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by itsacarr

Hmm mine certainly does not have a bevel on the inner edge on the back plate ... a shame there isn't more clear information on this because I have heard conflicting things from forums yet srm and cannondale say it should be fine lol.
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clingenpeel
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by clingenpeel

looks like my SISL SRM has the bevel and flat screws...it was orderd in Oct 2010...the bevel is very small...I just took my SISL SRM off my BB30 SL3, and bought an SL4, which has PF30...the conflicts I have read about appear to pertain to the SRAM PF30 BB, which does not look like the same as the PF30 BB that comes with the SL4...we'll see once the Frame comes in.

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itsacarr
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by itsacarr

I think I agree - ill have a verdict next week as well - SRM told me to get ahold of a pf30BB that they make which has a wider ridge on it I guess that works vs the SRAM one which will create problems.
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itsacarr
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by itsacarr

And by they I mean Cannondale:

KP197/SRM (part number for the specific pf30 bb and presumably sleeve)
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clingenpeel
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by clingenpeel

Are you putting the crank on a Cannondale EVO?

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itsacarr
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by itsacarr

Yes I am :) Thoughts?
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thisisatest
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by thisisatest

clingenpeel wrote:looks like my SISL SRM has the bevel and flat screws...it was orderd in Oct 2010...the bevel is very small...I just took my SISL SRM off my BB30 SL3, and bought an SL4, which has PF30...the conflicts I have read about appear to pertain to the SRAM PF30 BB, which does not look like the same as the PF30 BB that comes with the SL4...we'll see once the Frame comes in.

that is because specialized does NOT use PF30. they use their own system, similar to, but not, PF30. the difference is in the details, and the overall width, INCLUDING the lip on the plastic cup, is 68mm on specialized's system, unlike pf30.
that said, i know srm has a mod for the sworks crank SRM, basically moving their wavy washer from the left side to the right, to give the SRM just a little more clearance. since they need to do that, it is likely you would need to do something for an SISL on the same frame.

clingenpeel
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by clingenpeel

Wow, that's extremely interesting stuff. I did check back on the Specialized website for the Tarmac, and indeed they call their SL4 BB a "press-in OSBB"...I had assumed that meant PF30, but sounds like that's not the case.

Can you expand on the differences: for example, you say the specialized BB width is 68mm, unlike PF30...what is PF30, bigger or smaller? I'm guessing PF30 is bigger, based on your next comment.

Can you clarify this comment: that said, i know srm has a mod for the sworks crank SRM, basically moving their wavy washer from the left side to the right, to give the SRM just a little more clearance. since they need to do that, it is likely you would need to do something for an SISL on the same frame.

Why would that Sworks SRM mod imply I would not need to do anything for the SISL..Is it because the wavy washer on the SISL is already on the right side? Any guidance would be appreciated.

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itsacarr
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by itsacarr

On the road frames bb30 and OS30 are perfectly compatible.

Correct me if im wrong :)
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clingenpeel
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by clingenpeel

For the sake of my SISL SRM, and this coming SL4 frme...I sure do hope so!

thisisatest
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by thisisatest

clingenpeel wrote:Why would that Sworks SRM mod imply I would not need to do anything for the SISL

you would, most likely. but because the wavy washer is already on the right side, you don't have that mod to use. so cannondale has used a special srm-specific bearing shield, and an offset spindle.
as for the difference between pf30 and road osbb, i dont want to stray too far off topic, so i'll type quickly...
specialized road carbon osbb frames= 61mm wide (really). with their plastic cups, the overall width is 68mm.
pf30 frames=68mm wide. with the plastic cups, the overall width is wider than 68 (i dont know how wide, probably about 70mm, the flange on pf30 is much thinner than the flange specialized uses.)
they both use a 46mm OD for the cups. there is a lot of confusion because of their similarities.

itsacarr wrote:On the road frames bb30 and OS30 are perfectly compatible.
Correct me if im wrong :)


for the most part, they are compatible, but there are little issues that come up. for instance, cannondale's own sisl crank will rub a pf30 cup if you dont use their newest spider (that has a relief) and lockring (that has the outer corners rounded off). this would not be needed on an sisl mounted on a specialized. and certain adapters (campy) do not fit carbon osbb (specialized), (there may be a workaround for that, check the forums for that)

and theres the whole srm thing, the purpose of this topic.

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ms6073
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by ms6073

clingenpeel wrote:looks like my SISL SRM has the bevel and flat screws...it was orderd in Oct 2010...the bevel is very small...I just took my SISL SRM off my BB30 SL3, and bought an SL4, which has PF30...the conflicts I have read about appear to pertain to the SRAM PF30 BB, which does not look like the same as the PF30 BB that comes with the SL4...we'll see once the Frame comes in.

Earlier this month I was dealing with trying to install an older Hollogram SRM on a Ridley PF30 frameset which did not work so I sold it and got a used '11 SRM hollowgram. In my case, I orginally tried to use the SRAM PF30 bottom bracket but later opted to use an FSA PF30 bottom bracket which has a slightly smaller OD of the PF shell as well as ~1mm less inset of the bearings comapred to the SRAM PF30 bb. Using the SRAM PF30, I was not able to get the SRM to turn freely regarldess of the number of spacers or whether or not I used the SRM Spindle and NDS bearing shield.

With the FSA PF30 BB, I used both the SRM spindle and nds bearing sheild resulting in what I consider pretty 'symetrical' ds/nds spacing, although the back of the SRM on the drive side is oh so close to touching the FSA PF30 shell. To help illustrate my point about the back cover, here is an image of the back cover of my SRM where you can see the bevel in the center hole where the crank is inserted onto the spindle is rather pronounced. Also, Cannondale also offers an EVO specific lockring where the tabs are beveled to help avoid interference with the PF30 shell:
Image
- Michael
"People should stop expecting normal from me... seriously, we all know it's never going to happen"

clingenpeel
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Joined: Sun May 14, 2006 5:01 am
Location: Tennessee

by clingenpeel

I wasn't sure where to post this, but since this discussion migrated beyond just Cannondales, I thought I'd continue it:

I recently installed my SISL SRM on an SL4 with the PF OSBB offered by Specialized. My SISL SRM was purchased in Dec of 2010, and it did NOT look like the one above...it did not have that large of a cutout.

The SL4 came with a Specialized specific bearing cup and loose ceramic bearings (it also came with some press in adapters used for a standard Shimano crank...this is what you see if you look at the Specialized website and zoom in on the frame). The Specialized instruction manual found online says the bearings are 6806 series with an OD of 42mm, ID of 30mm, and width of 7mm. The cups were installed in the frame (installation manual says to grease), and the bearings were installed in the cups (again, it was stated to grease the bearings, not to locktight as they recommend with the BB that the bearings press directly into).

The SL4 is noted as having a 61x42mm BB, but with the plastic cups installed, the width ends up at 68mm. The width was confirmed with calipers after cup installation.

I used the STANDARD bearing shields (not the SRM specific one) and used the STANDARD axle length (not the SRM specific one). I used two black spacers on the drive side, along with the wavy washer. The crank (SRM power plate) cleared the frame. It's close, but there is no rubbing. I have not ridden it yet, so maybe sprinting may be different. But, if it rubs, I can easily add another spacer. It appears there is enough distance from the power plate to frame to prevent rubbing even in high torque situation though.

Since with the Specialized BB cups installed, the BB width is the same as my previous SL3 (68mm), I wouldn't imagine there could be an issue that didnt' present itself with my SL3.

Maybe with the SRAM PF30 design, the BB Cup flange is wider than 68mm.

Anyway, the setup of the SISL SRM on my SL4 was successful, as described, and no special adjustments, modifications, or SRM specific pieces (bearings shields or axles) where requried.

by Weenie


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