Folowing on from this thread….

http://singletrackworld.com/forum/topic/help-please-front-mech-shifting-help

I thought there might be more people able to help (now that everyone’s gone back to work after the BH weekend)!

Basically, replaced Sora 50t ring with a Stronlight 48t ring and can’t get it to shift from outer to inner (34t) for love nor money. It will shift from inner to outer with no issue

I altered the mech/ring spacing (position on seat tube) to accommodate the (very slightly) smaller ring, re-tensioned the cable, checked the mech angle and checked the limit screws.
But still couldn’t get it to shift.

I put the original 50t ring back on and had it shifting fine within about 5 mins.
One thing/difference I have noticed is that the Sora ring is dished/offset slightly so on a flat surface with the spider arms down, the teeth are lifted off the surface slightly. The stronglight ring is completely flat. I wonder if is this lack of offset between the spider and the teeth is causing the problem?

Another thing that makes me think the offset might be something to do with it, is that with the Stonglight ring fitted and the chain in the inner ring, when shifting down the cassette to the smaller sprockets, the chain scrapes against the inner face of the outer chainring.
It doesn’t do this with the original Sora ring (making me thing that the offset moves the ring slightly further outboard so the chain misses).

I did wonder if I have got the ring the wrong way round, but don’t think that I can have. There are shallow counterbores on one side for the chainring bolts that if I turned the ring around would sit against the crank spider and wouldn’t be doing anything useful.

Is it a singlespeed/track chainring perhaps? Got a link to what you bought?

I am using Stronglight 53/39 Zicrals on my Campagnolo drivetrain, shift is perfect.

This may be of use though, I was reading that mixing TA and Stronglight rings may give less than brilliant shifting as the gates/ramps/teeth are aligned differently and that shifting will be better if you stick to one brand. I assume you are mixing Stronglight and Shimano, that may be the issue?

Can’t say I’ve ever had a problem – refreshed my 105 compact drivetrain this weekend with 50/38 Stronglight 5083 rings and all went together fine and worked as intended.

As Woody says – is it a track ring/does it have the shifting pins through the ring?

I run them on my cx bike & did do for most of last season 44/36 & haven’t had any problems at all.

Are there any ramps on the inside of it? Sounds like it might be a SS ring?
Is it a 10sp ring but on a 8/9 groupset? Clutching at straws TBH, as difficult without actually seeing it.

I have stronglight zircal 42/53t. They shift fine, but not as smooth as Shimano.

woody2000, this is the chainring I bought:

http://www.ebay.co.uk/itm/STRONGLIGHT-DURAL-SILVER-110BCD-SHIMANO-9-10-CHAINRING-48T-/271451234155?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item3f33c11f6b

Hmmm, I assume it is not a track/singlespeed ring as the description says it is Shimano compact compatible and the description says 9/10 which I guess refers to the 9/10 speed.

mrmo, yes I am using a shimano inner and a Stronglight outer ring. I did some searching online before I bought it though and found nothing to suggest it might be a problem.

bristolbiker, it has shift pins I think (the one I have bought is also the 5083 ring that you mention). There are a number of pressed steel pins around the edge of the ring. But, this is where I wonder if I have the orientation wrong. These pins are almost flush on one side and protrude a couple of mm on the other side. The side they protrude on is what I am assuming is the outer face of the crank, as this has counterbores for the crank bolts and the brand marking of the ring.

I need to check this, but it doesn’t seem to have any ‘short’ teeth that I think the original Sora ring has. I need to confirm this.

goldenwonder, when you say ramps….? Are they pins or machined cuts/profiles? It has steel pins (see my comment above) but not profiled cuts like you get on a cassette).

For those using these rings, can you confirm which way round you put them?
I fitted the ring with the “stronglight” logo and the “48t” marker facing outwards. This was because the holes for the chainring bolts are counterbored on one side and I figured these counterbores should face outwards. If they faced inwards then they would sit against the crank spider and there would be no purpose to them being there.

Thanks for your help…..!

Got my outer ring from the same place 😉

There should be two small threaded holes in the face of the outer ring – in the cardboard packet is a small plastic bag that contain a small screw to put in one of these holes, so it fits behind the crank arm and stops the chain dropping between the arm/ring and jamming. I’m not sure which of the two holes to orientate with the crank arm (doesn’t seem to make much difference to the shifting), but this does give a guide to the angular orientation. You are right, the recessed holes indicate the outer face to accept the chain ring bolts.

So, that pretty much ties down the chain ring orientation….. if it doesn’t shift then, er, guess we’re looking elsewhere….

bristolbiker – yeah, there are two holes for the little catch pin. I put it in the one that is at the mid-point of the curved arm faces…..rubbish description, but I’m at work and my bike’s at home 🙂

Looks like I’ve got the ring the right way round as you’ve confirmed the orientation of the counterbored holes.

The chaps I got the ring from hae been replying to a query I made through eBay.
I will try to see if I can take some pics this evening that might shed some light, but I am riding tomorrow so don’t wanna mess the shifting up, fiddling about with it.

Perhaps it is just my ham-fisted setting-up but it’s odd that I can get the original Sora one working within 5 mins, whereas this one just will not shift down to the inner ring.

/keeps eye on thread having just bought same 48t Stronglight outer ring to replace 50t Sora ring/

Clutching at straws a bit now, but I’ve found with these cheaper rings, playing around with the radial clearance between the front mech cage and the outer ring (closer seems to be better) helps and I also set the mech up with the ‘tail’ of the cage plates pointing slightly inwards (towards the inner ring), rather than completely parallel to the ring, so it ‘flicks’ the chain coming onto the ring, er, off.

Also, have you replaced the chain and/or cassette at the same time?

kcal, let me know how you get on. You’ll probably just highlight my ham-fisted spannering!

bristolbiker, not changed chain or cassette.
Funnily enough, I did try slightly toeing the mech in a bit (and out a bit) but it didn’t seem to help. The mech height was pretty close, but perhaps something else to try tweaking….

will do! though currently bike is set up SS so this is a backup for when it goes back to double.. My spannering past is littered with cack-handedness so I’m not sure whether it’s a fair test.

For me I opted for the black over silver ring, so who knows 🙂

just did a similar swop to stronglight and didn’t have a problem. The front mech should be 5mm max distance between the bottom of the mech and the top of the big ring teeth.

The shifting ramps etc are usually not as good on non shimano stuff.

Mmm, I had similar issues when I mixed manufacturers of chainrings.

If the two different manufacturers work to a slightly different offset from the chainring tabs on the crank, you can have issues.

e.g if the distance between chainring centre lines should be 8mm* but one manufacturer offsets their chainrings 1mm more to one side, then suddenly you might find you have 9mm between chainring centres. Replacing all chainrings with one manufacturer’s means they all have the additional 1mm offset, so the 8mm spacing is maintained.

Its difficult to explain, hopefully that makes some sense.

*figures pulled out of thin air.

13thfloormonk, I think that might be the issue. The distance between the centreline of the teeth and the crank tabs does appear to be slightly different.

I had another look yesterday evening, although didn’t take the rings off to measure and the offsets do look different.
Might buy an Stronglight inner ring too, and see how it goes.