[misterchrisso]

Hi All. I have a 2014 Cannondale Trigger Carbon 2 29er and want to convert to a single chain ring. The frame has an ISCG/ISCG-03 mount and I found a suitable chain ring and guide. I’m guessing I’ll need a new, shorter BB to align the single chain ring and guide. There’s not much information out there on this particular conversion. Can someone please provide advice on which BB product/part number would suit? Thanks. Chris.

 

[Josh_W]

Your BB is probably fine - most direct-mount single chainrings will be offset to match your BB/crank type, so the chainline stays optimal. If you have a crank with a double spider, rings for the spider can usually be mounted on the inside or you can get a single-ring spider. At worst you'll have the same chainline as your outer ring has now, and can take some time to figure out what changes are needed, if any.

 

[Cannosseur]

The best conversion would be to a Cannondale Hollowgram Si crankset with single AI offset chainring. You will need the MTB Si Spindle 137mm length and the correct spacers 9mm on drive side, two or three thin spacers and wave washer on non-drive side. The Bottom Bracket, if BB30 or PF30 remains the same.

 

[misterchrisso]

Photo of setup

Thanks Guys for the feedback.

Here's the setup - embarrassingly unkempt.

Cannosseur, you suggested purchasing a new crankset and an offset chainring.

Would that successfully align the chainring, so that I can make use of a Fouriers chainguide, which attaches to the ISCG mounts, as shown in the photo?

Is there a cheaper way to do this? Can I simply purchase a shorter spindle that can fit the existing SRAM cranks?

Apologies, I've done DIY on everything else on my bikes over the years, other than the BB end.

 

[Cannosseur]

If it is BB30 then Cannondale Si Spindle, Crankarms, and Chainring will fit or sets from FSA, etc. are compatible or if you have Shimano compatible BB then several choices from Race Face, SRAM, etc. You just need to confirm your exact BB, spindle type and length for chainline offset, and your budget and make sure you get the correct spacers for each side. Good complete setup could start around $250, Cannondale Hollowgram Si complete set could run $600. Chain keepers from Shimano, MRP, Absolute Black, etc. fit the ISCG mounts.

 

[misterchrisso]

Bb30

If it is BB30 then Cannondale Si Spindle, Crankarms, and Chainring will fit or sets from FSA, etc. are compatible or if you have Shimano compatible BB then several choices from Race Face, SRAM, etc. You just need to confirm your exact BB, spindle type and length for chainline offset, and your budget and make sure you get the correct spacers for each side. Good complete setup could start around $250, Cannondale Hollowgram Si complete set could run $600. Chain keepers from Shimano, MRP, Absolute Black, etc. fit the ISCG mounts.

Hi Cannosseur. Thanks for your help, it's really appreciated. It's definitely a BB30, I believe the cranks are Truvativ and so is the new chainring, uses a Race Face "bash plate" on the face of the chainring, as per original parts. I'd like to try and use as many of the original parts as possible, as they're still well and truly serviceable. Can you provide the details for an online supplier for a Cannondale SI spindle/spacers? I'm in Australia and getting Cannondale parts is sometimes difficult. Thanks again.