Ultegra 8000 chainring combination 39/50

Discuss light weight issues concerning road bikes & parts.
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rainerhq
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by rainerhq

Shimano suggest to combine 39/53; 34/50, but will it actually affect shifting performance if I put 39/50 together or even 42/50?
I mean, will the front shifting be slower or...?
Domane
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Delorre
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by Delorre

Shifting will be fine for 99%, but you risk (I have seen several cases) cracking your big ring after a while. While shifting from 39 to 50, the chain in pushed againt the flat part of the 50, instead of the 'ramp' part if you use a 34. I've used 36/50 on a 9000 for years without trouble, but 39/50 is a real risk. And when you see the price for a new outer ring, especially 9000/ 9100 :shock:

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rainerhq
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by rainerhq

I used 39/50 combo for at least two years without problems. Inner ring was Ultegra and outer TA Specialites.
Other option for me is to use single front ring, but these 3rd party rings like Garbaruk are noisy and also 11-32 cassette is needed.
I think I´ll take the risk with 42/50 and 11-25 or 11-28 cassette.
Domane
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IrrelevantD
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by IrrelevantD

Another option would be to see if you can find 3rd party rings made to work 39/50. Though that is kind of an odd combination.
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rainerhq
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by rainerhq

What is the so called Paris-Roubaix setup? 44/53?
Domane
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kdawg
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by kdawg

I’m just curious as to why you’d want this? Are you a flyweight super climber? Most folks who think they want a big inner ring also want a big outer to mash on the flat/downhill.
I'm left handed, if that matters.

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Frankie - B
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by Frankie - B

I think he lives in a flat area. The 50 is enough for speed riding, but the 34 is way to small to ride around in. I ride the exact same setup on my sram equipped bike.
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rainerhq
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by rainerhq

Exactly. Flat land.
Last two years my setup was 48oval front and 11-32 or 11-28 rear..
Domane
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Frankie - B
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by Frankie - B

Rainer, you might also want to try a 36 chainring. as with a 50-39 the chain can drop between the rings when you are in the highest or lowest cogs of the cassette. I just re read this topic and I have made a mistake. I use the 50-36 combo. It stoppped using 50-39 after the reported chain drops.
'Tape was made to wrap your GF's gifts, NOT hold a freakin tire on.'

scale29
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by scale29

with a 50-39 the chain can drop between the rings when you are in the highest or lowest cogs of the cassette.

This is very much the case. I've been trying the 39/50 combo and the chain gets repeatedly jammed in the gap between the two rings, very frustrating.

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rainerhq
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by rainerhq

OK. Do think it will be the same with 42/50?
This should be only with Shimano big ring, because with TA Specialities I never had this problem,
Domane
"Nothing compares to the simple pleasure of a bike ride"

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kdawg
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by kdawg

What’s your cassette? It feels like you could use 52/39 with something like a 12-25 cassette which would have basically the same range but without the front shifting problems.
I'm left handed, if that matters.

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rainerhq
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by rainerhq

Cassettes are 11-28 and 11-32.
Bike comes with 34/50 crank, so I thought, the easiest and cheapest way is to change inner ring.
Domane
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srshaw
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by srshaw

I'd definately get a closer ratio cassette if I lived in a flat area. I remember back in the day riding 12-19 or something (with 52/52 chainset). Useless really since I live in a hilly area, but on the flat you could always dial in the perfect gear. I'd go 11-23 or 11-25.

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vejnemojnen
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by vejnemojnen

totally fine, esp. with 12-25 cassette ratio. 50-12 is quite enough for flats, and a 39t inner ring makes one able to use 39-15 or 39-.16, which are very handy ratios in strong headwind or riding around in the city..

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