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Discussion Starter · #1 ·
I posted this on MTBR.com, but it may have application for road bikes.

I have an old ’04 Specialized Enduro that I just love to death. I was upgrading the trigger shifters from the original Deore OEM to new XT models. The OEM ones were fine, but I wanted to upgrade after 4+ years of use. When I finished, the shifting was very stiff and shifting into the two lowest gears demanding more pressure from my thumb than I thought was appropriate. Major Disappointment. And I had already sold my old shifters.

The existing cables were probably less than 9-months old, as I buy small rolls of housing and replace often, and was shifting fine before the upgrade. I use Jagwire L3 4mm housing. I use 4mm over 5mm because I run full-length housing and had to drill-out some of the original cable stops to allow me to thread the housing though. I read somewhere that the inside diameter of the 4mm & 5mm are the same, but any feedback is appreciated. Full length housing has always worked much better for me; keeps the muck out of my cables and all the ferrule and nipple interfacing have to add friction.

I use generic SIS shift cables that I pick-up when I see a good price from Jenson, ProbikeKit, etc. Just your standard stainless cables, no gore/Teflon cables, never had the need to experiment as shifting has always been good.

So I swap out the shifters, run new cable and housing, feed into my old-style XT derailleur (not the original, but this one was probably two years old). Shifting is stiff and a real disappointment. I assume that the new shifters are the culprit, and start flushing with WD-40 and Silicone spray. No help.

Well, maybe that 2 year old derailleur is long in the tooth and a new XT Shadow would be a cool upgrade. Not hard to talk myself into buying one off E-bay. New shadow arrives, I mount it on the bike…. Shifting still sucks.

OK, I’m getting pissed. I’m no bike store mechanic, but I do OK. I build my own wheels, replace headsets, press suspension bearings, bottom brackets, have a Park derailleur hanger straightener tool (damn I’m cool), etc. What is the deal!!

Time to slay this beast. I decide to un-route the entire length of the cable housing and run it from the shifters to the derailleur, just letting it hang while I’m diagnosing in the garage to see if I have created hot-spots / pressure points in my routing. Shifting is improved a little bit, but still sub-par. PISS! Guess I’ll cut & run a new length of housing, maybe this section has a blemish in the sheathing.

I cut a new section of housing and get out my roll of spare shifting cables. HEY! What is this! These spare cables are not all the same diameter!! WHAT!?! Light-bulb goes off….

So apparently derailleur cables come in different diameters. I choose the smaller one of the group. Sorry I do not know the size, as I don’t have a micrometer available. I can see and feel the minute difference, and the smaller one is MUCH more pliable. I route the new smaller cable, VIOLA!!! Shifting is PERFECT!!

Lesson learned. So I guess I need to figure-out what the smaller diameter is and only order those spares in the future. Also, if anyone can validate that there is no inside diameter difference between 4 & 5mm housing, that would be great. Maybe my initial assumption was wrong and there are specific cables to use in each?

Sorry so long of a story, but I thought it may help someone. Don’t spoil it by saying I’m the only idiot to make this mistake.
 

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Militant commuter
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It might be a difference between "drawn" cables or simple wound cables. I don't think the drawn ones have a very measurable diameter difference, but they ARE smoother and function better, especially tight bends in the casing.
 

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The gear-cables I'm running measure at 1.09mm on my digital-calipers. They are round-wound coated stainless-steel. Unsure of the manufacturer/seller. I buy them through my LBS. They state they are top-end.
 

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Rub it............
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There are 4 different sizes with derailleur cables

1.1 mm, 1.2 mm and 1.5 mm, and 1.6 mm
 

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Discussion Starter · #5 ·
1.5 and 1.6? Wow, I doubt those would have fit in the 4mm housing sheath. Are all four sizes available with the standard Shimano SIS end on them? Maybe some of mine are 1.1 and 1.2mm. My larger one was definitely not 50% bigger than the other. I'll have to mic them and find out. Thanks!!
 

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info...

The only common diameters are 1.1mm for SRAM and 1.2mm for all others. Anything larger would be some ancient and/or cheap cable.
 

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'brifter' is f'ing stupid
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frdfandc said:
There are 4 different sizes with derailleur cables

1.1 mm, 1.2 mm and 1.5 mm, and 1.6 mm
1.5 and 1.6 aren't derailleur cables, they're brake cables. the ends are a dead giveaway...:D
 

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1.1 for SRAM and campy, and some aftermarket brands in this spec. Putting the 1.2 cable into a housing made for 1.1 cable sometimes works and sometimes doesn't in my experience. Also check that you don't have an obstruction at the end of the housing due to how it was cut - that's a pretty common problem.
 

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cxwrench said:
1.5 and 1.6 aren't derailleur cables, they're brake cables. the ends are a dead giveaway...:D
Not always. Think Vision Tech aero TT brake levers w/the shifter cable end and 1.5mm wire. Yer slippin' old man!
 

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'brifter' is f'ing stupid
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wunlap togo said:
Not always. Think Vision Tech aero TT brake levers w/the shifter cable end and 1.5mm wire. Yer slippin' old man!
dohhhhh...you're right. and some of our girls use those levers!
 

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cxwrench said:
dohhhhh...you're right. and some of our girls use those levers!
Ha ha, I couldn't let that one slide! We should go ride mtb, I've got my brother's blur to pound on!
 
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