psychling78

I have an old triple Shimano Octalink crankset. The service instructions state that ONLY SG-53 FC-6503 chainrings may be used on this crankset. Are there truly no alternatives?

Iride01 

Do you remain stopped at stop signs? They never say go.

That's probably their concern. I'd look to see why they had that concern and then see if the ring I want to replace it with addresses that. Sounds like it's something with the way one mounts on the other.

psychling78

Yep, that's the same service bulletin I have. Can't find anything at Sheldon Brown that contradicts this, so I'm a bit flummoxed.

OTOH, given how persnickety the front shifting is, I have a difficult time believing that a chain will "get stuck" between two rings, as the bulletin warns.

dsbrantjr

Another problem might be that if you buy chainrings from someone else Shimano won't make any money.

Crankycrank

You can use most chainrings of the same BCD and 5 arm. IMO Shimano's are the best as they have the best shifting ramp setup for quicker shifting to another ring. Stronglight and Specialties TA are 2 very good quality mfrs that make durable CR's and are not much noticeably slower in shifting speed and might not even bother most people. Make sure to get their top tier versions. Lately there have been quite a few aftermarket mfrs. that get good reviews and are less expensive and other posters may have some experience with them to comment on. If you want to change the number of teeth on each sprocket for different gearing most offer different sizes too.

Iride01 

Well most of it is probably because when Shimano introduced this new tech that a lot of the other stuff had the potential to be an issue. Chains and everything were changing at the time period I'm imagining your bike was made.

If you haven't already, take the rings off and look to see how everything attaches and whether there is any thing about they way they are shaped... if not completely flat, or if the mount for the spider or other rings is half lapped or something.

If this is an old Shimano component, then someone probably makes stuff that fits by now. Unless you are too far in the past and these are just too different to make it worth selling one ring every 20 years to the only persons that want them. But I doubt that's your case.

dedhed

I suspect the warning has more to do with using 6/7/8s chainrings as they used the wider chain and 9s spacing was new. YOu probably won't have any issue running 9/10 chainrings.

KCT1986

There is nothing unusual about these cranks. Measured a set of FC-6500 crankarms. The thickness of the mounting point, where the rings sit is about 3.5mm. Measured some Shimano from the 6,7,8 speed era and had the same measurement. The chainrings may align the teeth slightly closer together to compensate for the narrower chain.

With a 53/39 setup, certain OEMs added a thin spacer on the mount separate the rings a little. With short chainstay designs, the chain would rub against the large ring when using the small ring and smallest 1 or 2 cogs in the rear.

So most 9/10 speed rings would probably work. Depending on combo of rings and chainstay length, thin spacer might be needed to avoid the rub problem.

curbtender

I put a Salsa middle ring without ramps and, yes, the chain got stuck between the rings. So there is some truth there.

psychling78

Mine's a triple -- which is why I got the Octalink crank in the first place. I do have a decent caliper, so I can do some measuring to see if the spacer might be an issue.....

KCT1986

Sorry about not catching that you have a triple, the mention of 53T (which was double only), made me think that it was a double.

Regardless, at this point, you'll probably have a hard time getting original replacements. 105, 550x series triple would be the closest options. Other mfg rings would also be possible but shifting may not be quite as good. The positioning and design of the shift aid may be different. It all depends on your expectations.

If you go to 10 speed rings, then thin spacers may be needed to properly 'gap' the rings. Different mfg offset the teeth differently.

oldbobcat

Ah, 9-speed triple chainrings with a 5-arm 130 mm BCD spider. The only triple road crankset by Shimano that fits that description is Sora CG3030, and I haven't been able to find the chainset or the crankset in stock. There is also a model just called Sora 3x9, with the new asymmetrical 4-arm crank spider. But for your 6503 cranks you need paired outer and middle rings with a 5-arm 130mm BCD, plus a 104 mm BCD inner ring.


I know of two alternatives. First, FSA makes a chainring pair for triples, 50-40 or 50-42. Your local bike shop can order these from QBP. These are milled for 10- and 11-speed but I've never seen them not work for 9. Q also has a 30t inner by Dimension that will work. The other alternative is to replace the crankset with new Sora 3x9, plus a BSA-threaded outboard bottom bracket, also available at QBP. This won't be a whole lot more expensive than replacing three chainrings and it might get you some insurance against more obsolescence.

HillRider

That's it exactly. FC-6500 was the first of the 9-speed groups and older 6/7/8-speed chainrings were indeed spaced a bit further apart and a 9-speed chain could slip between them. Any 9 or 10-speed chainring (FC-6600, FC-6700 or their 105 and Dura Ace equivalents) will work fine.

KCT1986

The FC-x700 series was the beginning of the spider with the integrated hollow spindle and had a different chainring attachment. No bolt hole on the outside of the spider, and different attachment of the smallest ring. Need to check the BCD/PCD of the 3 rings. The 9 speed cranks used 130/74 BCD.

curbtender

When we get some swap meets back you can usually find them. A lot of riders switched out to compact so there are usually a few laying around.

davidad

I think that this is the main reason.

davidad

TA rings are expensive, but they last and have **** pins so they should work.

HillRider

Not exactly. Yes, the FC-X700/03 did have hollow spindles built into the drive side crankarm and used HTII external bearing bottom brackets. However, the 10-speed 105 FC-5700/5703 had a standard symmetrical 5-arm spider and standard through bolted chainring bolts. T30 heads, not 5 mm hex but standard type nevertheless. The triples also had 130/74mm BCDs just like earlier triples. The 10-speed Tiagra FC-4603 triples also had standard 5-arm spiders, standard T30 chainring bolts and 130mm BCD for the two larger rings and a nonstandard (and unfortunate) 94mm BCD for the granny ring that bolted directly to the middle chainring.

70sSanO

You can get TA’s or even Vuelta SE Plus. I’m running 48/38 Sugino flat rings on my 6503 crank. The 6503 30t is still available on eBay.

It’s not that tough.

John

Iride01 

When you finally do find your chain ring make certain to compare the cost to just getting a entirely new crankset and maybe even new BB. For me, that's been a better option every time.

I'm willing to spend a little more for completely new, than just putting a new part on an old component.

psychling78

Thanks to everyone. My faith in this forum has been rewarded. The bike in question is a 1997 Cannondale R300 with a 3 x 8 drivetrain. I'm getting it repainted soon, since I'm a little long in the tooth to justify upgrading. I'm also a little sentimental and frugal, so I'll run the setup I have until it can't be done any more. I do 3-4K a year on this bike, so that may be sooner than later. Again, thanks to all of you. I appreciate the wealth of information and perspectives you provide.

I'll let you all know what happens!

Roadies_Rok

If someone is having issues with the chain coming off the chainrings or potentially getting jammed between the small and large chainrings that is an adjustment and setup problem and not an equipment compatibility problem. For most of my life I have run Shimano groupsets only for the reason that they came on most bikes I wanted not because they were good or better or even worth buying. I much prefer Campy but that's my opinion. The chainring "spacers" that were mentioned they are micro thin about the thickness of a piece paper. Every time I tore down a crank to clean the rings they would drop onto the floor and I could never figure out where they went so into the bottom of my tool box they would go and I never had shifting issues without them. I have a strong feeling the spacers are a classic case of engineers trying to justify their existence.

Unless someone has a very old crankset like 20 years old or older all chainrings come with pins and ramps. The last race bike I had I took off the 53 tooth and put a 50 tooth chainring on because I wanted to get the chain closer to the middle of the cogset when I was on the big ring. This was the 1st generation Shimano DuraAce 10 speed that had the exposed shift cables. The "official" Shimano chainrings were $100 each so I bought an FSA chainring for $45 and lived happily after. 5,000 miles after I put the FSA 50 tooth chainring onto my bike it was shifting as smooth as ever.

Just as an FYI the "03" as in 6503 is the designation Shimano uses for a triple chainring. "00" and "01" as in 6500 or 6501 designate a double chainring. Hope this helps.

oldbobcat

3x8, that's a horse of a different color. QBP has a few Shimano Claris R2030 3x8 cranksets with 170 mm crank arms. These should retail for under $110, US. You would need a BSA threaded Hollowtech II bottom bracket, about $20, currently out of stock, but I'm sure there are a few lurking around Amazon and Ebay.