frogbiscuit

I had to do a little tweaking on my Specialized Sirrus rear derailleur and the 8 speed Shimano Altus seems a little cheesy. Not 100% familiar with the Shimano hierarchy, what would be considered an upgrade for an 8 speed rear? I would like to stay Shimano so all I would have to do is change the rear derailleur.

Eric S.

A Shimano Sora derailleur would work fine and looks as good as many others higher up Shimano's line. I just checked eBay and you can get a new one for about $25.

Iride01 

Why do you think it cheesy? Altus is fine for an 8 speed. I suppose you could move up to a more expensive line of Shimano, but realize the higher you go in the line, probably the more speeds they were intended for.

I assume this is for a mountain bike. So it's a little out of what I'm used to, but if you do go for an different model or newer model of the same then be certain the pull ratio's for the DR aren't different. Usually not, but I think at some time on the road bike DR's shimano changed the amount of cable pull needed to traverse the cassette stack. They may have done similar with the mtn bike line. So a newer or different model DR might require a different shifter too.

Shimano's line up of components is here...................... https://bike.shimano.com/en-US/components/mtb.html

Bill Kapaun

Altus shifts my 9 speed just fine.

Lemond1985

I just replaced a bent 8 speed RSX RD with an Altus one a couple weeks ago. The Altus shifts great, takes a 34t cassette and was only $20. My only gripe is it's a little heavy, but for $20, I won't complain.

frogbiscuit

See my Altus doesn't look like that. It's black and mostly plastic. Are there different grades of Altus? I am just wondering if maybe I bent it in the fall, I should replace it? It seems to work fine, but took a bit of a beating.

Iride01 

I don't know that there are different grades, but Altus is just a name of the product line/tier level. So the design periodically changes over the years. Someone else once described it like car models..... Same name, but different every year.

Thankfully bike parts are a little slower to change.

And if things are working fine. Don't be in such a hurry to spend money. Save for another bike.

fietsbob

Those Big Bottom Pulleys Do a good slack take up without such a long cage ..

Lemond1985

Yes, I agree, they do. Plus it has nice strong springs, so you don't end up with a weak RD with worn out springs that refuses to drop into the smallest cog.

HerrKaLeun

Unless the RD is worn out or not adjusted properly, all shifting quality is a function of the shifter.

Also check hanger alignment.

Kapusta

Any Shimano 7, 8, or 9 speed RD will work with your shifters and an 8 speed cassette.

Whether you need a mountain or road RD depends on the largest cog you are running, but I assume that since there is an Altus on there now that you need a mountain derailleur.

That said, unless your RD is worn out or broken, upgrading it is one if the least useful ways to spend money on your bike.

Lemond1985

Or bent like mine was.

Bill Kapaun

If it ain't broke....

frogbiscuit

Yeah, the hanger was bent and so was the cage that holds the pulley. Did a couple of 15 milers, after some adjustment, seems to work fine. Just wondering what would be an upgrade, if there is one.

Wilfred Laurier

I believe the hierarchy in MTB and hybrid components is:

Altus -> Acera -> Alivio -> Deore -> SLX -> XT

In my experience, when new, the cheaper stuff works 99% as good as the more expensive stuff. I don't know if all the groups use the same 'pull ratios' - an SLX derailleur might not index properly with the shifters that originally came on your bike.

robert schlatte

I needed a new derailleur on old foul weather beater bike. I bought a Shimano Tourney (lower in the hierarchy than Altus) for $12 on Amazon. It works flawlessly. It is a little ugly and heavy but I could care less. You could go up a grade or two and be very happy but maybe not necessary? Is there a bike co-op in your area. I have found beautiful used parts for next to nothing at my local co-op.

Lemond1985

Co-op idea seconded. I like experimenting with different-sized stems, and the co-op sells them for like 5-10 bucks. Forks, seats, and pedals I've gotten there. One good thing you can really save big on at co-ops is crankset chainrings, for trying out different gear ratios. Those cost a fortune new. Also, used cassettes are cheap.

bakerjw

FWIW, our road tandem came with Claris shifters and a 3x8 drivetrain. I swapped out the front and rear derailleurs with 105's and it worked quite well.
IIRC, 8 and 10 speed chains are the same inner width, it is the outer width that changes.
I have since upgraded the shifters to 105s and it shifts even better now.