Bnystrom

The crankarm measures 50mm at the center of the spindle, but it tapers to 47mm at the point where the recess in the chainring ends.

Bnystrom

I'm not that desperate yet, but I'm getting close!

Schadenfreuder

Ordered up a set of SL-K rings 46 and 30T from Italy (The German supplier had ran out).

Many thanks to Bnystrom and xraydog for getting me the sizing information - much appreciated.

I'll post a pic or two when (if they fit ) installed...

Could be a good way for Cannondale crank owners to drop down to 46/30 ~ 48/32 without having to fit an entirely new crankset.

1Mule

Have you considered a Goat Link and running 11-40 rear?

https://www.wolftoothcomponents.com/...ts/goatlink-11

Cyclist0108

Yes.

Bnystrom

I've encountered a pretty serious problem with this combination, though it should primarily be an issue when used off-road or on rough gravel roads. In fairness to FSA, it has the potential to be a problem with any BB386EVO crank that's used with a PF30 or BB30 bottom bracket.

Here's what happens:

1. The chain pops off the bottom of the inner chainring due to bouncing.
2. It slips past the heads of the chainring mounting bolts, which are not recessed into the inner ring.
3. When you start pedaling again, the shoulder of a mounting bolt catches the chain and drags it up toward the chainstay (similar to chain suck). This also drags the chain down onto the bottom bracket spacer and jams it between the bottom bracket and the inner ring attachment points.

At this point, pedaling in either direction is impossible without serious damage to the chain, rear derailleur and/or frame. It requires flipping the bike over and carefully pulling the chain back out, then re-seating it on the chainring. If you have a chain catcher on the bike, the chain may get pulled past it, requiring even more effort to get it back in place.

The good news is that this could be prevented by a simple add-on plate that recesses the chainring bolt heads and fills the gap between the chainring and the spindle adapter. The bad news is that I don't know of anyone who makes such a thing. I'll feed this information back to FSA and see what they have to say.

UPDATE:
FSA is aware of the issue and we're discussing it currently.

This is not a problem for frames that accept their MegaEVO BSA threaded bottom bracket. I've tested it and there isn't any way for the chain to jam with that combination.

UPDATE 2:
I machined a plastic collar (70mm diameter x 10mm thick) that press-fits over the FSA spindle adapter and prevents the chain from jamming. It sits slightly proud of the chainring bolt heads and prevents them from grabbing the chain. Now, if the chain bounces off the chainring on the bottom, it falls harmlessly on the BB shell and re-engages as soon as I start pedaling. If anyone wants to see pics of it, let me know.

I've passed this information on to FSA, so hopefully they'll come up with their own solution.

Schadenfreuder

Oh no! I fear the worst!

Reading Bnystrom's last post has just made something occur to me...
As the FSA SL-K uses a BB386EVO spindle and the Cannondale slate has a BB30a BB - both of which I was all perfectly aware of prior - there's every chance that the SL-K modular outer ring will not be "dished" as much as a Cannondale Spidering.
That is a Cannondale Spidering maybe dished outward 5mm (my estimation) more than the SL-K modular outer ring. So a SL-K modular ring mounted on a Cannondale Si crank may give a chainline 5mm closer to the frame than a Cannondale Spidering would.

I came to this realisation when I considered that if I were to install a SL-K crank (like Bnystrom) on a Slate I would need a drive side adaptor / spacer to increase the BB30a 73mm BB upto a compatible BB386 EVO width of ~86mm.

And here's me thinking I was being so clever eh?!

ArDachaidh

I fitted the IRD 12-36 cassette and find the extra low gear a help on the hills, as expected. I feel a compact + (or ++) would be useful but the cost/benefit doesn't seem worth. The Sugino would fit the Ultegra but at £350 for one extra low gear from a 46/30 I can't justify it at the moment. An even smaller inner ring might make me think again, but I don't think it's available in the UK.

Bnystrom

The Sugino will accept down to a 24tooth or possibly a 22tooth inner ring. Finding one configured that way could be a challenge. You can customer build one online, but it's really expensive.

ArDachaidh

Thanks, Brian. As you say "expensive" - I'll keep thinking and looking. Regards, Graham

Cyclist0108

That's the really nice thing about the White Industries crank I wound up getting. You can put on whatever chainrings suit you.

Inner ring: 24- 38 even increments

Outer ring: 38-52 even increments


VBC RINGS ? White Industries

ArDachaidh

I had looked at the WI and priced it up from Germany, but it also meant a new BB, whereas I believe the Sugino is direct replacement. Not much difference in price either, unfortunately, but as you say highly versatile. Regards.

Bnystrom

Correct, the Sugino crank would fit your Shimano BB. While the White Industries crank is certainly versatile, I couldn't bring myself to go back to a heavy flexible, square-tapered bottom bracket. If you're willing to make that sacrifice, there are other alternatives that are made it Europe, such as TA and Rene Herse. Perhaps you can get a better price on them.

FamilyMan007

WGScott

Just want to thank you for starting this thread - I ended up going with the Sugino for my new bike. The 46/30 crank seems to my inexpert eye to be well made (and delightfully packaged!), and operates flawlessly using Ultegra Di2 (perhaps something to do with the meticulous assembly by my bike fitter - Mark Dwyre - through whom I ordered the bike)

Amazing to see the number of views this thread has generated - perhaps Shimano will take note that there is a market for something smaller than a 'compact' chainring.

Best wishes
Peter

Cyclist0108

Although I made that "sacrifice," they also now have a 30mm spindle version (actually several). In my case, I couldn't quite fit it because I have a Di2 hose in the BB shell as well.

Cyclist0108

I still wonder if I should have gotten that one. Glad you like it.

TimothyH

@FamilyMan007, did you get the 901 or 601?

Was this a conversion from a Shimano crankset? If so then I'd be interested in hearing about how much the front derailleur had to be lowered to get it to work properly, or if it had to be lowered at all.

Any other info on getting it to work would be warmly welcomed.


-Tim-

FamilyMan007

I purchased the 901 - my new bike was an indulgence, so extra cost vs 601 was not a determining factor for me

fyi - It was installed as part of a new build with the 46/30 as a planned replacement on the Ultegra crank from the outset. (You can decide whether the answer should have been yes or no!)

N/A in my case as this was planned from start of a new build. (My understanding - but not definitive information - is that there is sufficient adjustment in the front derailleur to accommodate the smaller crank, but perhaps that depends how the derailleur is attached to the bike frame).

I installed Di2 on my new build - I heard from one builder that Di2 accommodates the 46/30 better than mechanical units, but I do not know if that is reliable as I ended up going with a Ti frame from a different builder.

Mark Manners has made some valuable posts on this thread, has had greater experience than most. You would be well advised to look up his posts.

Good luck

TimothyH

Thank your for the thorough and thoughtful reply. I really appreciate it.


-Tim-

Bnystrom

I don't know if it's better than mechanical, but the D12 front derailleur does shift the 46/30 well. A bit more chain wrap capacity for the rear derailleur wouldn't hurt.

Schadenfreuder

For Cannondale Hollowgram crank users I've had some information back from Dr Cannondale in Germany:

The Spider fitted to the Si cranks on the new 2018 CAADX 105 SE or SYNAPSE DISC 105 SE models use the FSA 120/90bcd 4 bolt arrangements, so can take FSA 48/32 (as fitted on these bikes) or 46/30 chainrings.

These rings are pretty easy to get hold of and 11 speed retail for about 30 / 15 Euros respectively.

Dr Cannondale are trying to get hold of these spiders.

ArDachaidh

Update to my 12-36 cassette. I adjusted the B screw to create more clearance between the jockey wheels and the cogs. Then I discovered the Ultegra has 2 Trim positions, so I adjusted the front derailleur cable as the chain was rubbing at times and all seems fine.

Re the FD adjustment for a smaller chainring, I see mine has no further adjustment but you can get a simple adjustable FD mount to sort that. So if I were to go Sugino at some point, I would need that too.

Bnystrom

That's interesting about the Cannondale cranks. However, that outer ring is not the same one that comes on the SL-K Adventure crank. The SL-K outer ring incorporates the spider and mounts directly to the crankarm. I'm not sure what FSA crank the chainring shown comes from. Are you sure that it's available in a 46 tooth size?

EDIT:
I just checked the FSA site and these are apparently the Vero Pro chainrings (based on the bolt circle and cutout shape), which appear to be available only in 48/32.
https://shop.fullspeedahead.com/en/di...chainring-3055

I have to question how good they are considering that they come on a $74.00 crankset.

Schadenfreuder

FSA's website is a labyrinth. If you don't have the exact part number you often can't find the item you're looking for.
OMEGA/VERO PRO chainring
This link takes you to the Omega / Vero Pro items.
As for quality? Cannondale have chosen to fit the FSA rings to their venerable Si crankset (same as my Slate) using a new Cannondale spider with the FSA 120/90bcd.
This setup is now on two of their (while not quite flag ship) more interesting 2018 models.

My Slate 105 has fairly basic FSA 52/36 rings and hasn't shifted badly on me yet. My older Arkose 1 had a FSA 9 speed crankset which worked well, and I only changed the it for a Sugino 601 because I couldn't get a small chainring less than a 33t with the road 110 BCD at the time.
But as you say you get what you pay for, and this option could get exist Cannondale users a 46/30 or 48/32 set up for maybe under €100/$100...

Bnystrom

"Labyrinth" is definitely an apt description!

Since the rings are available in 46/30, this would make a nice combination if you have a Cannondale crank or can get one at a good price. I've seen them on Ebay and other sites for reasonable money, so it's definitely an option. All you need is a source for the spider.