I've recently purchased some Fibre-Lyte standard 2 chainrings in a 53/39 for my Clavicula cranks. The good news is that these are super light and pretty stiff (noticeably stiffer than the Tune rings they replaced), however I'm experiencing an issue with shifting from the big to the small ring.

The problem is that when shifting from big ring to small, the chain quite frequently drops so that it rests with the outer plate of the chain on the top of the teeth of the inner ring, rather than shifting onto the teeth of the inner ring.

The Fibre-Lyte rings are machined with the teeth spaced to the inside (bottom bracket side) of the inner ring. Flipping the ring round the other way (so the teeth are spaced towards the big ring, effectively reducing the gap between the rings), solves the shifting problem, but means that the chain catches on the lift pins from around gear 7 at the rear cassette.

Has anyone got any ideas or experienced any similar problems?

I've spoken at length to Stephen at Fibre-Lyte, who has been very helpful, but we've not hit on a solution yet and he wasn't aware of similar issues with other customers. He suggested I tried a forum post.

The rest of my set up (which may obviously be a contributing factor or a cause) is:

Storck Fascenario
SRAM Red (2011, the one they've supposedly hardened) front mech
KNC X10SL chain
Clavicula cranks

The set up did work fine with the Tune chainrings.

Any feedback appreciated.

Cheers,

Did Stephen say which the "correct" rotation direction is?

If I had to guess I'd say they are supposed to have the teeth towards the big ring, and I'd also guess the shortish chain stays on the Storck aren't helping. I'm not blaming the frame, just showing that there are many combinations that are beyond the control of a single manufacturer.

There are two solutions I can think of:

1) is using very thin washers to get the desired spacing where you don't get chain skating but get to use more cogs in the rear. If your crank/bb setup allows for this, you could move the entire thing to the right to alter the chainline, too, but I'm not sure if you can do that with the Clavicula. Doing a bit of both would probably give you the best result with the least compromise. I'd definetly contact THM to check if those modifications are ok with their crank, they are great guys there and with the really light and expensive stuff you gotta be aware that you have to be extra careful before fooling around.

2) Flip the chainring around and try the following tip from the master:

_________________
"Nothing compares to the simple pleasures of a bike ride," said John F. Kennedy, a man who had the pleasure of Marilyn Monroe.

I've had the same problem; while shifting from big to small ring, the chain would drop between both rings.

My setup is:

DA7900
Zipp Vumaquad crank
50-34 Fibre-Lyte rings

The straight-forward solution was to have the FD move more towards the frame by unscrewing the low limit.
Problem solved (90% of the time)

Thanks.

_________________
My Parlee Z1

Hi da123

My Fibre-Lyte 53/39 rings are attached to a a SRAM Red crank with the machined step in the rings facing each other and I have not experienced this problem any time during the 12 months of use.

From you comment about turning the inner ring around I suspect that maybe the thickness of the Clavicula crank ring mounting is greater than that on a SRAM crank. Have you compared the thickness of this part of the crank with other cranks? (I just tried to measure my ring back to back distance but my dial calliper will not reach into the rings that far - maybe someone has a disassembled SRAM crank they can measure?)

That was one of my first thoughts Oberon but we've done countless sets of chainrings for the Clavicula without any problems.

After our conversations it sounds to me as if the chainrings are set up correctly and he's checked the chainring thicknesses and the crank spider feet thickness and all are what they are supposed to be so all I could think of was the front derailleur set up or a chain line issue. I know that da123 has tried flipping the inner chainring to reduce the spacing, which I wasn't keen on as I knew it would affect the chain line/lift pins catching. The only other thing I could think of, which I hadn't mentioned yet, is if the lower pulley in the rear derailleur cage is toward the outside of the bike a little too much (bent?) and is pulling the chain out over when shifting down. It's unlikely though. Trouble is, we don't have access to the bike so we can't really see what's going on, everything is discussed over the phone whcih is quite difficult when setting up a bike.

As da123 mentioned, the set up did work fine with Tune chainrings. He also mentioned in conversation that he thought the front derailleur hanger flexed a little more than his old bike. From what I'm told theTune chainrings are flexier than ours, which made me wonder if the combination of more flexy chainrings, the Sram Red fd and a slightly flexy hanger enabled better shifting but once our slightly stiffer chainrings were fitted, whether that affected things. Seems unlikely but...

At this point, I don't know

Having had similar issues with different set up, i would certainly check the rear hanger alignment using park tool or similar.

This issue caused me a few weeks confusion as it had been confirmed at build then 2 months later with no crashes and storage in the heated and carpeted garage on a wall rack... no events which would bend it... turns out my 2 yr old daugther had knocked it over in the garage (carpetted floor so no scratches etc...), and her 4 yr old sister had picked up "because she knew daddy would be cross...." bless em.. little buggers....

Thanks for all the input - much appreciated. Lots of things to try, so fingers crossed I'll get it sorted.

I ll semi-hijack the thread to ask something about these chainrings. I really like those Fibre-lyte, they look awesome first of all and they are lightweight. My question is, are they designed for long distances? I am doing around 250miles per week and I don't really want to change them too often. What's the verdict in durability? Also what chainbolts are recommended for them?

_________________
Planet-X Nanolight HM - 6.19kg

To be honest they're not really a very high mileage chainring. My own sets usually get around 6-8000 miles but I do spend most of my time on the big ring. It does vary though. We have had customers get as little as 2500 miles and as much as 10,000 miles (both claimed).

Durability... as long as you're not 'on the power' when shifting at the front they should be fine. When I say 'on the power' I simply mean that you need to avoid chain slip from over zealous shifting. It's not good on alloy chainrings either but can cause more issues on carbon chainrings. If used as a single ring, you won't have any problems.

Chainring bolts, any you like that you would use for normal alloy chainrings. I use Shimano, Tune and I think T/A or Tiso (can't remember which they are without looking!)

da123 did you solve the problem somehow? I am experiencing the same issue with my SR11 crankset. 1 out of 2 downshifts end with the chain between the rings.

_________________
Planet-X Nanolight HM - 6.19kg

I have a SR11 setup with a Vumaquad crank and have the same problem.

Back to this as it's getting a bit annoying at this stage. Have tried spacers which made the shifting 20% better but it's still faulty, the chain ends in the middle lots of the time. Any other ideas before they go to the sales forum?

_________________
Planet-X Nanolight HM - 6.19kg

Hi Chaps,

Just to add my 2p. I found this when I built a Cervelo R3SL with new standard Campy SR (all standard rings no FL rings). I couldn’t understand why the chain kept slipping in between the two chain rings. When I looked into it in detail, it seemed like it was an ‘issue’ with the frame and front mech being somewhat incompatible. Basically the way the front mech braze on was set, it didn’t allow the front mech to move enough inside (to shift from big to small ring).

I built this bike for a friend and set it up the best I could but he occasionally still has this annoying issue. I think the fix that someone noted about ‘reshaping the outer cage’ will work – but if its carbon then you run the risk of this cracking.

I would conclude that it is an incompatibility with the frame shape / braze fitment and Campag fitment.

Not the answer you were after but hope this helps someone??!!

Cheers,
Lig.

_________________
3kbikes.co.uk
For best - Parlee Z3
For training - Colnago EPS AKBL
For the pose - 1980'ish' Basso Steely

I think that this is one of the problems with custom set ups. I remember not so long ago where a customer had a vuma quad set of chainrings from us and no matter what he tried he couldn't get them to shift right. The same set of chainrings were used by another customer who thought they shifted flawlessly. On that basis, we could only summise that the set up was to blame and not the chainrings. However, that doesn't help customers where the set up doesn't seem to work properly, especially where another set of chainrings appears to work ok. My own opinion on setups where the chain is dropping between the rings, regardless of the chainrings used, is that either the front derailleur needs adjusting for reach or the chain line is somehow incorrect. If the problem was a regular occurrence on similar cranksets/bikes then there could be a chainring issue but if some set ups work and some don't, I think that there could be other factors than just the chainrings.

Then again, I could be bias

I have the same problem every now and then I'm using praxis rings on m3 cranks on a parlee z5 with campag mechs...

After reading this I should be able to dial it out bringing the inner limit screw in a bit.. I like to run the front mech as tight as I can get away with, 3 clicks up I think now I or it set up a little too tight...

There is a work around that won't solve the problem but will stop it from happening...

Lead with the rear a bit more... It only occurs when you cross the chain towards the 11 or have the chain line straight with Reguard to the big ring. If you move up towards the 23/25 cog more before shifting down ( leading with the rear... ) it won't happen.

_________________
http://fairwheelbikes.com/cycling-blog/ ... ee-z5.html