Replacing Sugino chainring on an old Fuji
 

I have an old Fuji Boulevard, from about 1984, I'd like to replace the large chainring.
Chains keep wearing out too fast, around 500 miles. Have changed the freewheel but
that doesn't help much. The chainring does appear to be slightly worn so hopefully
changing this will help.

The bikes specs show the crankset as follows:
Sugino Aero No. 5 36 x 46T
satin finish chainring. 170 mm
alloy cranks with chainguard.

Any suggestions for a bolt on replacement ? I've found a few NOS Sugino chainrings on the
auction site, but I think the mounting holes spacing is critical.

mikey89, Search the web for "chainring bcd". Wolf Tooth has an easy to use tutorial and charts.

Brad

sheldon brown has a bold circle measuring guide https://sheldonbrown.com/cribsheet-bcd.html


but actually you may be able to find a whole crank set for the price of a couple new chainrings..

because bike factories buy cranks not individual chain rings so manufacturing volume favors the whole assembly costs..


guessing they're steel, got a magnet?



....

Chainring looks fine to me, and replacing it won't fix your chain wear issue. What are you using to determine when to replace your chains?

Park Tool chain tool ...... once it gets beyond the .75 mark its about time to replace.

+1. Additionally this crank has a different ring/arm relationship then the usual. Note how both rings mount on the arms' backsides, also look at the ring bolt and how it might be a different design then the common ones are. If the OP really wants easy future availability, a range of tooth counts, the nicer shifting that comes with pins and gates I suggest just replacing the crankset as a unit with a more current/common design.


Have you tried a different chain brand? Andy

I've used a few KMC Z50's and also some NOS Black Izumi (Japan) I found on the auction site.
Izumi seems to last a little longer. Might try an SRAM next to see if it lasts longer.


Also, I think the larger ring which I use more....... shows somewhat more wear than the smaller one.

Agree with the others that those chainrings look in good shape from what I can see in the photos. Not likely to make any difference in chain wear if you get new ones. Wish my rings looked that good. Your chain looks pretty dry. If that's how it normally looks you're probably not lubing it enough.

I'm pretty sure that large ring isn't removable or replaceable. Can you post a pic of the back side of the chainring?

IIRC correctly, that crank has steel chainrings, which ought to last the lifetime of the bike.

Agreed. Those are pressed steel and the inner doesn't look particularly worn.

IMO, I think you should try a SRAM chain, perhaps a PC-870:
https://www.universalcycles.com/shop...13&category=61
SRAM chains have been good to me.

Chain checkers can indicate excessive wear that doesn't exist.
Use a steel ruler and measure to check your checker.

The outer chainring is removable, it has five allen head screws holding it on.
This is the best picture of the other side I have on my laptop....

For now I think I'll just try a different brand chain like SRAM.

The fenders I added last weekend will definitely help the chain life :-)
Lots of grit and sand all over the paths where I ride.

+10 those steel chain rings last just about forever. Your problem is elsewhere.

Forget the Park chain wear tool. Use a ruler instead. Much more accurate. KMC Z50 chain is $6.50 at Walmart.com, local store pickup. Handles up to 7 rear speeds, I'm guessing you have five.

500 miles on a chain is way off. What lube are you using?

[QUOTE=mikey99;20127343]Park Tool chain tool ...... once it gets beyond the .75 mark its about time to replace.


Use a ruler or this tool to check chain wear. https://www.amazon.com/Pedros-Chain-...n+checker+plus


Chain life is a function of maintenance. Chain care, wear and skipping by Jobst Brandt

The large ring on that crank is riveted in place and cannot be easily changed. While the small ring unbolts you might have trouble finding a replacement due to the BCD (Bolt Circle Diameter). If you are happy with the current crank's gearing, then fix your chain problem and keep riding; those rings appear to be okay.