Old 01-09-19, 03:35 PM
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Join Date: Oct 2018
Location: SE USA
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Bikes: 2018 Fuji Jari 1.5, 2019 Trek Domane SL5

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A few issues with indexing Shimano 105 5800

Hey Everyone,

First off, a big thanks to everyone who's responded to my previous threads. Being that the place we purchased our bikes (Performance) is no longer willing to help any of their customers with issues with their bikes I'm taking this as an opportunity to learn more and tweak the bikes we have myself. Of course that means many more questions from a newb such as myself.

With that said, I've been trying to figure out a weird issue with my wife's Fuji Cross. First a few specs, it has 105 5800 front/rear derailleurs and shifters but the cranks are Oval with Praxis chain rings (46/36). It's supposed to have a Shimano 105 11/28 cassette but I haven't been able to verify that exactly but for now I'm going to assume it's also 105 5800 (being that it's 11/28 which it appears the R7000 doesn't offer).

Now to the issue... shifting into higher gears seems a little clunky while shifting back down is much smoother. The issues are worse when in the larger chain ring where it barely shifts up at all unless I continue to click the shifter up and down. I spent a few hours today reviewing a number of youtube videos to see how to index the rear derailleur and I have it working beautifully on the bike stand but when we take it on the road it's still very clunky on the up shift (into smaller cogs). It seems to perform best when in the smaller chain ring but on the larger chain ring it's a nightmare to get consistent shifting. Sometimes it will go into the gears just fine but other times it appears it catches on one of the teeth on the cassette and it sort of skips for a moment making it a rather clunky shift. This isn't what I would expect from a 105, even if it's the older model. I also understand this isn't their top of the line stuff but I expect it to at least shift and not skip gears etc.

Having done a little research on the 105 5800 groupset I noticed they don't offer a 46/36 chainset but the true 105 starts at 50/34 and goes up from there. I was wondering if changing the chainset would help the shifting at all. I would go to the R7000 chainset but I ready that would require a new front derailleur at the very least and I'm not sure if the R7000 would be compatible with the existing shifters/cassette (the R7000 doesn't seem to offer an 11/28). Or am I looking too deep into this and should I continue to focus on indexing?

As it stands, she can use the bike when in the smaller chainring and deal with the clunky up shift for a little bit but being these bikes are just a few months old it's a bit of a bummer that it's all not working as expected. All help/advice is greatly appreciated!
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