Chainring questions; ramped or unramped?
09-14-09, 07:33 PM
#1
Jet Jockey
Thread Starter
Chainring questions; ramped or unramped?
I currently run a 50/34 Shimano 105 outboard bearing compact double on my cross bike. 110 BCD. I think, based on my usage, that I'll get more efficient use out of this crank changing out the chainrings for 48/36.
I've found two 48 tooth chainrings that fit the bill. One is a Sugino unramped and unpinned chainring available at a great many places, in the neighborhood of $35. The other is an older 5 bolt 110 BCD Shimano XTR for around $75.
My question is this: I've never used "plain" chainrings. I know that ramped/pinned are better for shifting, but is that XTR chainring over $40 dollars better performing? Will my shifting get all kludgy with a plain chainring. Bear in mind that I'm using STI shifters, so it doesn't exactly have all the crude adjustment capability of a friction shifter.
I've found two 48 tooth chainrings that fit the bill. One is a Sugino unramped and unpinned chainring available at a great many places, in the neighborhood of $35. The other is an older 5 bolt 110 BCD Shimano XTR for around $75.
My question is this: I've never used "plain" chainrings. I know that ramped/pinned are better for shifting, but is that XTR chainring over $40 dollars better performing? Will my shifting get all kludgy with a plain chainring. Bear in mind that I'm using STI shifters, so it doesn't exactly have all the crude adjustment capability of a friction shifter.
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09-14-09, 07:57 PM
#2
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unramped and unpinned chainrings have been around for a long time.
that said, they usually didn't have big jumps between teeth count, like the classic 42/52 road setup or the 30/40/50 triple setup.
Your 12T jump with 36/48 shouldn't need pins or ramps.
that said, they usually didn't have big jumps between teeth count, like the classic 42/52 road setup or the 30/40/50 triple setup.
Your 12T jump with 36/48 shouldn't need pins or ramps.
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09-14-09, 08:15 PM
#3
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I had a "plain" SR crank on one of my older bikes with 52/42/26 unramped rings and I changed it for a 105 triple with exactly the same chainrings. Even used with a barend (friction) shifter, the shifting improvement was dramatic. Shifting under load was particularly much better but even under low load conditions the shifting was superior.
It's your money but, if it were mine I'd spend it. BTW, Harris Cyclery has 48T 110 mm bcd TA rings for the same cost.
It's your money but, if it were mine I'd spend it. BTW, Harris Cyclery has 48T 110 mm bcd TA rings for the same cost.
09-14-09, 08:37 PM
#4
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What used to be perfectly acceptable shifting in pre-R&P days is no longer acceptable to many.
That said, I replaced the Shimano rings on my tandem's triple with plain Jane Sugino rings to get just the right gearing (lower) and to save a few bucks. The shifting is perfectly OK (by my standards).
That said, I replaced the Shimano rings on my tandem's triple with plain Jane Sugino rings to get just the right gearing (lower) and to save a few bucks. The shifting is perfectly OK (by my standards).
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09-14-09, 09:00 PM
#5
Jet Jockey
Thread Starter
I had a "plain" SR crank on one of my older bikes with 52/42/26 unramped rings and I changed it for a 105 triple with exactly the same chainrings. Even used with a barend (friction) shifter, the shifting improvement was dramatic. Shifting under load was particularly much better but even under low load conditions the shifting was superior.
It's your money but, if it were mine I'd spend it. BTW, Harris Cyclery has 48T 110 mm bcd TA rings for the same cost.
It's your money but, if it were mine I'd spend it. BTW, Harris Cyclery has 48T 110 mm bcd TA rings for the same cost.
I just found that IRD offers a ramped 48t chainring for $60. However, I hear mixed reviews on IRD components; some are fantastic, and others are garbage.
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09-14-09, 11:47 PM
#7
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FWIW: I have older non-ramped and non-pinned chainrings on my Ultegra triple crank, shifted with Shimano Deore LX "Rapidfire" trigger shifters and a FD-R443 front derailleur. They work fine- probably a little slow on the upshifts, but not what I'd call objectionable. Of course, I've been playing around with triple cranks since the early '80's, so I know how far things have come.
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09-15-09, 05:45 AM
#8
Jet Jockey
Thread Starter
Keep in mind that with my chainring changes that the "gap" I'll need to cover is less than with a standard 39/52.
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09-15-09, 06:58 AM
#9
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I've never tried these but if the price certainly seems right even if they aren't quite as smooth as Shimano rings: https://www.universalcycles.com/shopp...8&category=650
09-15-09, 08:20 AM
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Yes, the TA rings are ramped and pinned. You are paying for both shifting performance and bling. 
09-15-09, 08:34 AM
#11
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Are you sure that the XTR chainring that you are looking at is a 5-bolt 110mm BCD?
Personally, I go for TA rings whenever I have a choice. They are ramped and pinned.
Personally, I go for TA rings whenever I have a choice. They are ramped and pinned.
09-15-09, 11:00 AM
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Here's a ramped FSA for a little less.
https://aebike.com/page.cfm?action=de...=30&SKU=CR3952
(ETA: never mind, it's out of stock)
Note that ramps and pins work best when the inner ring has the right alignment to the outer, which is why they're designed to match specific rings from the same manufacturer. For a custom choice of chainring you will have to determine the best alignment for yourself:
Before putting the crank on, take a length of chain and loop it over the inner ring, with the outer plate of the chain catching on a pin of the outer ring and then flowing up the ramp onto the outer ring. For a good shift the chain should should be able to fit snugly on both rings without riding up on top of the chainteeth.
Check this at each pin on the outer ring -- with a non-matching set some of the shift points will be better than others. If you don't have 2 or 3 working shift points then rotate the inner ring by one bolt and try again.
https://aebike.com/page.cfm?action=de...=30&SKU=CR3952
(ETA: never mind, it's out of stock)
Note that ramps and pins work best when the inner ring has the right alignment to the outer, which is why they're designed to match specific rings from the same manufacturer. For a custom choice of chainring you will have to determine the best alignment for yourself:
Before putting the crank on, take a length of chain and loop it over the inner ring, with the outer plate of the chain catching on a pin of the outer ring and then flowing up the ramp onto the outer ring. For a good shift the chain should should be able to fit snugly on both rings without riding up on top of the chainteeth.
Check this at each pin on the outer ring -- with a non-matching set some of the shift points will be better than others. If you don't have 2 or 3 working shift points then rotate the inner ring by one bolt and try again.
Last edited by zzyzx_xyzzy; 09-15-09 at 11:04 AM.
09-15-09, 03:52 PM
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I'd go with the TA rings. If Harris (Sheldon Brown) doesn't have the ones you want try Peter White Cycles. TA offers "10-speed" chainrings now.
Al
Al
09-15-09, 04:53 PM
#15
Jet Jockey
Thread Starter
AEbike has them here for about $71. Tree fort did yesterday, but I can't find them today. I'm either not searching the same, or they've sold out.
So I guess it's the "NOS" XTR, or the TA...
I'll just go with a plain jane Sugino inner. Obviously no reason for anything fancy there.
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