SlowCrank

Hey gang,

I'm looking to swap out my 7 speed freewheel and 105 RD for an 8 speed set up. My LBS says I should get a new Deore 8 speed RD (long cage).

Is this a good suggestion, and are there other options out there?

I've got a 53/39 crank and Ultegra 8 speed bar end shifters.

CACycling

What is the range of the cassette? You need an RD capable of handling the 14 tooth crankset difference added to the difference between the smallest and largest cogs on the cassette. That will determine if you need a long, medium or short cage RD. And number of speeds isn't really an issue. You can use an 8, 9 or 10 speed RD as long as it can take up enough chain for your application.

shelbyfv

What size cassette are you using? If it's 32t or more you will probably want a mountain rd such as Deore or LX. If 28t or fewer, a 105, Tiagra or other road rd. A 9 speed may be easier to find and will work well. Just don't get a 10 speed mountain rd (Dyna-something.)

SlowCrank

I haven't picked up the 8 speed freewheel yet actually. So if you know of a good 8 speed freewheel RD combo that would be helpful Thanks for the suggestion on the crankset tooth difference, I'd wondered about that but wasn't sure how it played in.

shelbyfv

Since your LBS mentioned Deore, I'm guessing that you are looking for easier gearing than what you have. If so, Jenson has 11-32 SRAM cassette for $25, 8 speed SRAM chain for $18 and a nice LX rd for $39. Those are fairly normal online prices, your LBS will be higher. Maybe they will install for free to offset some of the difference.

SlowCrank

Hrm... that RD looks nice. I'm guessing you mean this one -

https://www.jensonusa.com/Shimano-LX-...ear-Derailleur

Will it work with the Ultegra bar end shifters? I think it will but I keep seeing that the Deore RDs work best with the Rapidfire trigger shifters so I want to make sure.

Also, to clarify, I do need a freewheel and not a cassette, my rear wheel has a Phil Wood freewheel hub and I'm loathe to swap that out

FastJake

Depends what gearing you want. First look at what gears you have now, and get a freewheel that either matches those or doesn't depending on what you want. Although you might not have many choices in 8S freewheels.

Good that you mention this. It's a common mistake, and I'd initially assumed you were mistaken.

shelbyfv

Yes that's the one. I've used it with brifters but not bar ends. I think index is index, either method. Oops about the freewheel/cassette. You DID say freewheel, I just missed it. Didn't even know they made 8 speed freewheels!

SlowCrank

Yeah, I'm definitely looking to ease the gearing, I'm coming off of some tendonitis and this bike will be my commuter/back-up roadie/beer run bike once it's all set up.

8 speed freewheels are a not too hard to find, more like odd to find, and there aren't a lot selections.

So... it sounds like I just need to find an indexed RD that can handle the gearing on the freewheel that I end up getting while taking into account the difference in chainrings on the crankset... is that my lesson for the day?

davidad

Your 7 speed der. will work with an 8 up to about a 28 to 30 tooth cog.

SlowCrank

I guess I should add this is the RD that's on my Centurion currently -

https://velobase.com/ViewComponent.as...3-45ebc7fe703f

And when I say it's hard to find a freewheel, I mean I haven't found one that only goes up to 28T that isn't overpriced.

CACycling

I saw the FW comment but assumed when you said you were going to an 8s setup you were changing out the wheel or, at least the hub. There are inexpensive 34T 8s freewheels out there but don't know anything about the quality:
https://www.niagaracycle.com/product_info.php?products_id=729765

SlowCrank

Alright! So I'm getting closer. How does the math work to determine correct cog options, with crankset, and RD? I'm assuming there's an amazing sheldownbrown.com article out there, but I'm not even sure how to begin to searching for it.

CACycling

One way is to use a gear calculator (I like this one as it is easy to use and it takes everything into account: https://www.gear-calculator.com/# ). Run the numbers with your current set up (chainrings, cogs, tire size, cadence) then figure out what you are trying to accomplish with the new set up and play with the components till you get what you are looking for.

SlowCrank

Awesome. Thanks for all the tips and help folks!

Bill Kapaun

That's a cheap Chinese made FW. Problem may actually be is when one wants to remove it.
It appears you need a special FW tool that may not be readily available??

DCB0

The Deore rear derailleur will work 100% perfectly with the Ultegra bar end shifters.

The only shimano rear derailleurs that won't work are pre-9 speed Dura-Ace (which wouldn't work with the larger cogs anyway) and new 10 speed 'Dyna Sys' MTB derailleurs.

SlowCrank

So I've been researching this a bit over the intervening days. It looks like the Shimano RD-1055 I'm using can hold up to 28T for max cog size and chain wrap. If I can track down a 8 speed 13-28T RD, would the RD-1055 still work even though it's designated as a 7 speed RD?

I'm hoping yes, just to save some cash, but it also looks like I can find some Shimano 600 RDs on ebay for the 13-28T freewheel.

As always, thanks in advance.

Kimmo 

FTFY

Not to mention pre-SIS stuff.