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· Fini les ecrase-"manets"!
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Discussion Starter · #1 ·
My wife asked me about this, and I wasn't sure how to answer.

She almost never uses the large chainring (52) and occasionally, on a really bad hill, will resort to the granny gear on her triple. As she's already succumbed to the "triples are for sissies" pressure from my cycling friends, she's wondering if there's a way to get more useable gearing while staying out of the granny. We don't ride particularly fast--her top cruising speed is 21, if she's second wheel, but she can do 16-18 all day--so she doesn't need a huge top gear.

What she's thinking is to get a 50 tooth large chainring to replace her 52, and maybe replace her 42 tooth middle ring with something like a 39 or even a 38. And she'd probably ditch the granny gear, just for cosmetics.

She's got a nine-speed 12-25 Shimano cassette--I'm not sure what the tooth counts are on the various cogs.

So here are the questions:

1. Is the 50/39 or 50/38 combination going to have tons of gear overlap, leaving her with a gear selection that's too narrow?

2. We've only found Salsa rings so far, without shift ramps. Is her shifting going to go completely to hell, or can we make it work OK? (she's got Tiagra shifters/deraillers).

3. If not having ramps is an issue, how about staying with the existing 52 with ramps, and putting on an unramped 39/38. Is that too big a drop?

My own take is that she should just ride through it--she's climbing better every week, and will eventually have better strength on the flats, so the 52 won't seem quite so big. She's OK with that answer, but I'd like to know if there are other reasons not to do this.
 

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Aftermarket Triple Chainrings

I think smaller rings would be a good idea but recommend that you find some that are designed to run in a triple. TA Specialties Allez rings are for triples with ramps and pins. Others are FSA and IRD. You may have problems getting the front derailleur adjusted low enough if it is a "braze-on" type, if clamp-on this won't be a problem.
I replaced the chainrings on my wife's Ultegra triple with TA Allez 49-39-28 rings. It was necessary to grind down the slot in the derailleur hanger to get the FD low enough. The teeth on the TA rings are thicker than the Shimano rings and I had a problem with the big ring to middle ring shift when the chain was on the smallest two rear cogs. The chain was riding on the ends of the teeth instead of dropping over them. This was solved by moving the chainline out with a 1.5 mm bottom bracket spacer and by filing a slight bevel on the inside of the middle chainring teeth. Now the shifting is good and she can use all 9 rear cogs from the middle ring. TA rings are sold by Sheldon Brown and by Peter White.
 

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A compact is a 34 or 36/50

What are you trying to avoid? Buying a new crank? 110 bolt pattern cranks make life alot simpler when trying to mix up rings. Lots of compacts on ebay. It does get into more problems like spindle length for the BB etc when going triple to double.
 

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I run a 38 (Salsa) inner with 50T TA outer on Ultegra 9sp cranks, with 13 - 26 on the back - the cassette's a mix of Ultegra, 105 and SRAM cogs, BTW. Works fine for me and the hills around where I ride.

Got the TA from Branford Bikes - they do online. Shifting is fine, as good as with the 39/53 I started with. Not sure how you'd fare with the Salsa or TA 38 in a middle position - they aren't ramped for upshifting to from a smaller ring. Plus you could run into snags with the front der not liking the new ring spacing and sizes.

As above, be prepared to work at getting a decent shift from new, mixed components.

I started with a triple four years back, eventually got fed up with the complication, didn't really need it, so went double and eventually backed off to 38/50. My new toy has a Shimano compact 34/50 rig which is a delight for shifting gears, but the 12T cog is pretty much a passenger - can't use it at all for cross-chain case on the 34 and can't use it but for show on the 50 because my legs don't seem up to it ;)

Most of us non-racing riders, even some of pretty good ability, ride around on heavily over-geared bikes - if 53 x 11 or 12 is good enough for pros, it's unlikely to a limiting factor for we mortals

Hope that helps

Dereck
 

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50/39 is farther apart than 52/42, not closer together. There is less overlap. See www.sheldonbrown.com/gears

You can get ramped and pinned 9sp 39t middle rings from FSA. I put one on my wife's Ultegra 9sp, replacing the 42t middle ring. The derailleur needs a bit more trimming but works fine other than that. I think I got the ring from Branford.

As far as triples being for sissies, she should try passing her friends up a hill while using the triple. That demoralizes them much more effectively than passing them while struggling on the middle ring.

If she really wants a double, you can use a 38t unpinned ring and a 52t outer ring and that will work fine. It's the same range as the standard 53/39 racing setup. With a double BB and derailleur and you can erase all traces of geeky tripledom.
 

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frankenbike

i've got a frankenbike that's been moded over the years from a triple up front with a 13/29, 7 speed in the back to a double running 38/52 rings in the front while still using a triple front derailleur. i'm also running 8 speed sora shifters up front connected to the original 7 speed rear derailleur.
needless to say i swore at this setup for 6 mos before i got it tweaked just right but since then it has been worry free and shifts quite well.

the lesson for the day is that you can make any setup work with enough patience and 4 letter words.
 

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39t

I'll agree with others and say the the FSA 39T middle ring is a relatively cheap solution. A 42T middle ring has never made any sense to me. Changing to a 12-27 cassette would provide a very modest improvement, making the 39/24 the lowest ratio that should be used before shifting to the little ring.

Before anyone protests the statement about the 39/24, remember that the middle ring on a triple is in nearly the same position as the big ring on a double and the chainline should be treated as such. The middle ring and largest cog isn't a smart combo to use for very long, just like the big ring and largest cog on a double.

The attached picture shows the forbidden combos with red lines.

http://cgi.ebay.com/FSA-Pro-Road-Ch...ryZ36133QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

http://aebike.com/page.cfm?PageID=30&action=details&sku=CR4028
 

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I've never been a fan of 52-42-30 gearing, because I tend to think of the little ring as a bailout gear that I should almost never have to use. I had such a crank but replaced the middle ring with a 38 from TA. I had to replace the Ultegra-9 front derailleur with one designed for the bigger jump (10 vs 14 tooth) because it was rubbing on the chain a lot in the middle gear. I ended up with an Ultegra-10 FD, but Dura-Ace 9 would probably work better.

I personally don't think it's worth it to replace the big ring with a 50. It would probably make more sense to look at a compact crank -- you can often find them (with external BB) on eBay for around $100, which won't be that much more than replacing two chainrings, and it would save a lot of hassle. In this case, you'd still want to replace the FD.
 

· Larry Lackapants
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I've just seen Truvativ Elita cyclocross offers 130 BCD and 39-46 chainrings. I'd definately try out one of those chainrings - actually both of them. Ok the 46 is small and won't look "cool". As i see on the picture on the site, the rings are pinned(mybe ramped too).
 

· Fini les ecrase-"manets"!
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Discussion Starter · #11 ·
Thanks everyone for the advice--very good thinking here.

I'm still not sure what we're gonna do. She's leaning toward a conversion to double, I think, so with the advice here, I'm going to swap the BB as well and make it a real conversion instead of just ditching the small ring. C-40's diagram shows it would be a much better idea to go at least that far.

Could be that she'll opt to get stronger, but she did seem really disheartened to discover that my lowest gear was actually LOWER than her middle ring's easiest combo, so we may go to a 38 or 39 middle at minimum.

Thanks to all who provided brands and sources for ramped replacement rings. I've dealt with Branford and Harris before and both have been good, so we'll go there.
 

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C-40..a question

C-40 said:
Before anyone protests the statement about the 39/24, remember that the middle ring on a triple is in nearly the same position as the big ring on a double and the chainline should be treated as such.
I have seen you make this statement numerous times and have often wondered why this needs to be the case. I'm sure you know that there are ways to position the middle ring such that the chainline produced falls in the middle of the cassette, thereby reproducing the same chainline as the double. I'm curious then why the prefered setup is the one you describe. Yeah, I know that when one follows the manufacturer's recommended combos, you are presented with very few choices. But if talking slightly old school (square taper BB w/ infinitly variable chainline), the possibilities are limitless.

I suspect issues of Q factor and/or front derailleur travel, but I can shoot down the latter. Not questioning your wisdom hear, just curious about the thinking.
 

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there are limits..

I thought the same thing, until I realized that most frames only have 3-5mm of clearance between the little ring and the chainstay. You really can't move the middle ring 6mm to the left, where it normally is.

There's also the matter of limited FD travel. With a Campy triple FD, there's an arm that will hit the seat tube, limiting the FD travel. On my bikes, this arm is a fraction of a millimeter from hitting the seat tube. If the middle ring was any further to the left, the shift from the middle to little ring would never execute. I guess owner of metal frames could put strategically located dents in the chainstay and seat tube, but with carbon that's not an option.
 
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