Chainring position on crank?

[LollyKat]

I ordered some Spa XD-2 (triple) cranks, and Spa Zicral chainrings, plus the fixing bolts to put them together myself. They arrived today but I'm not sure how to position the rings, with all their ramps and funny cutouts. The anti-jam pin on the outer ring doesn't line up with the crank - it is 36 degrees out - and there is no option to change it.

The XD-2 uses a captive bolt behind the crank arm. The new TD-2 crankset has all five bolts visible, and it is clear that the anti-jam pin does line up properly with this model.

Is this going to cause problems with 1. shifting (Tiagra STIs) and/or 2. chain jamming? Will the ramps and pins be 36 degrees out from optimal? Should I just send them back and exchange them for Stronglight rings which have a choice of two pin positions? I accept that it serves me right for buying Spa's own-brand stuff. With hindsight I can see from their website picture that the rings aren't compatible with the XD-2 but it is not pointed out on the page.


I need to return the cranks anyway as they have sent me the wrong length - 165 instead of 160 . I would have chosen the TD-2 for looks but it only comes in 170.

TIA

[andrewjoseph]

Didn't bother my wife and I with same cranks.

[531colin]

Do you need the anti-jam pin? I can't remember when I last un-shipped a chain that side.
Have a look at the backs of your chainrings on a well-used chainset. Mine all have marks to show that I habitually change at a certain point in the cranks revolution......it doesn't seem to match up with where the manufacturers put their ramps and pins.......

[gaz]

.

[beardy]

You would position that ring at 180 degrees, so the peg is opposite the crank, keeping the symmetry.
The peg looks like the Stronglight one which unscrews with a spanner, if you could have a hole drilled and tapped in the right place (right through the Spa Cycles logo ) it would all be as you want it.

I did have one crankset that didnt sit right on the tapers and the chain was forever going in that gap, doesnt happen so often now.

The Stronglight one must sacrifice the ramp and pin position by 36 degrees on one of the cranksets when fitted. I can not say I have noticed any ill effects on mine.

[531colin]

.................The Stronglight one must sacrifice the ramp and pin position by 36 degrees on one of the cranksets when fitted. I can not say I have noticed any ill effects on mine.

Quite so!...
Can't say I notice any difference between new rings with pins and old rings with no pins, come to that!

[LollyKat]

Many thanks, everyone - it sounds as if I don't need to worry.

The peg looks like the Stronglight one which unscrews with a spanner, if you could have a hole drilled and tapped in the right place (right through the Spa Cycles logo ) it would all be as you want it.

I thought of that but unfortunately it seems to be riveted. Still, it sounds as if the lack of it isn't going to cause a problem.

[Mick F]

Do they not have timing marks etched on the faces?

My Campag triple has diamond shaped marks, so you line them up on all the rings when you assemble them.

This is a piccy of a double chainset.
A are the diamonds and B is the logo.

Screen shot 2014-05-09 at 11.13.02.png (12.65 KiB) Viewed 2739 times

[LollyKat]

No, they don't. Besides, looking at your picture I wouldn't necessarily consider the diamonds lined up, or at least the one on the inner could be rotated anti-clockwise and it would still seemed lined up to me .

I think I can see from the ramps how they go, though, and the marking for the number of teeth lines up so I'll use that for my guide. Life is so much easier with plain rings and DT shifters....

[andrew_s]

I put the anti-jam pin on mismatched outer chainrings where I figure it's least likely to bite my shoe, ankle or leg. That means just below the crank when the crank is forwards.

Stronglight chainrings have a screw-in pin that can go in either position, with the hole for a hidden bolt chainset located just clockwise from the hole for a 5 visible bolt chainset (looking at the outside face). That means that your fixed pin would go just above the crank, with the crank horizontal/forwards (i.e. the other side from where I'd put it).

I'd rather have the lower price than worry about pin location.

[MGate]

Funny that about your cranks because on Tues I ordered the same in 165mm and 160mm turned up on weds!

[LollyKat]

Mine are down as 160 on the enclosed invoice but clearly stamped 165 on the cranks - not clearly enough, obviously! You're not in Glasgow by any chance, so we can do a swap?

[MGate]

Mine were 165mm on the invoice and 160's were in the bag...

Glasgow - sorry - would have been easy to swop if I had! I'm in North Yorks. I'm sure we'll get the right size next week!

[LollyKat]

Or then again we may not....