XG-1090 vs CS-7900

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

I am looking for a cassette 10 spd 11-23..

the XG is lighter by a bit, and I read vs the previous OG it's got quieter, all steel durability so leaning towards the XG1090

XG cost a little more, how long does the Ti cogs on the CS-7900 last?

rijndael
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by rijndael

The XGs got a bit quieter, but IME they're still not as quiet as Shimano cassettes.

by Weenie


RussellS
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by RussellS

The largest four titanium cogs (17-19 and 21-23) on the 7900 series 11-23 ten speed cassette should last almost forever. How often do you ride in the big cogs? There is zero wear if you never shift into the big cogs. Where I live the big cogs are still brand new after the cassette's middle cogs are worn out.

PoorCyclist
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by PoorCyclist

I would say a lot in the 23 for climbing but I don't think the larger cogs skips or wear that fast, it's the mid cassette that gets hammered that starts to skip when worn for my cassette.

The thing that seems attractive to me with the SRAM is like -30g if I am correct, which is quite a bit. Also I am running the 7900 group if that matters. The SRAM chain shifts and fit sloppy on the front and rear I would like to put back on CN-7901 soon

rijndael
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by rijndael

The cn-7901 is probably the best 10 speed chain for shimano/sram users. Not just in shifting, but also from a friction/efficiency perspective.

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mpulsiv
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by mpulsiv

How does SRAM get down to ~140 grams on OG and XG cassettes using steel? Correct me if I'm wrong but these should outlast CS-7900 (steel + Ti)?
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n808
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by n808

Except the largest cog (and possibly smallest), the XG-1090 is machined out of a single piece of steel. Excerpt from SRAM description: "The whole cassette requires a machining process so complex and precise that each piece takes around seventy minutes to produce."

My version, 12-27T (155g), without the elastomer StealthRings is quite noisy.
Update: Fine-tuning cable tension for the rear derailleur seems to have reduced the noise level quite a bit. And gear changes are pretty flawless.

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Last edited by n808 on Sat Aug 02, 2014 2:36 am, edited 1 time in total.
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Imaking20
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by Imaking20

On my 2012 RED group I have run everything SRAM, a 7900 cassette, and a 7900 chain. The quietest setup was everything SRAM. The 1091R chain on 7900 cassette was never as quiet (and it was fussy) and the 7900 chain never remotely impressed me.

So my vote would be 7900 cassette if you're running all Shimano now. I doubt the XG will shift as smoothly or quietly in that arrangement.
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mpulsiv
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by mpulsiv

Ah, I missed the fine print https://www.sram.com/sram/road/products ... 0-cassette
Largest cog is made out of aluminum. Longevity it out of question for those of us who spend majority of time dancing on pedals.
From what I hear titanium cogs on CS-7900 can last up to 5k miles. Again, it all depends on terrain.
Racing is a three-dimensional high-speed chess game, involving hundreds of pieces on the board.

:arrow: CBA = Chronic Bike Addiction
:arrow: OCD = Obsessive Cycling Disorder

n808
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by n808

Hmm, I did not realize the big cog was aluminum either. It looks and feels like the matte gray steel on my old 2004 11-23 Dura-Ace cassette. Hopefully it will last a while.

Fine-tuning cable tension for the rear derailleur seems to have reduced the noise level quite a bit. And gear changes are pretty flawless, compared to my previous PG-1070, which was bought used with more miles on it than the seller claimed.
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eric
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by eric

The large cog spreads the wear across more teeth than any other cog. You'd have to ride in it for most of most of your rides to wear it out. Most people wear out the smaller middle cogs first, like the 16t, even on cassettes with the larger cogs made from ti.

Supposedly the Sram red cassette large aluminium cogs are individually replaceable but they seem to be difficult to find.

kulivontot
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by kulivontot

I had recon all alloy cassette. I'd get wear and chipped teeth only in the smallest cogs. I think the stress is greatest in that range since you're applying force over a smaller amount of teeth and you're most likely to lay down a 1500W sprint in your 11 cog than your 25T.
That said, I switched to XG 1090 last January and have had no issues with it. It worked both when I had Shimano and sram shifting.
IMO, the SRAM cassette is a better buy. Lighter, about the same cost, plenty quiet, shifts great, durable, and won't spontaneously explode because of a defective carbon carrier design.

rijndael
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by rijndael

kulivontot wrote:won't spontaneously explode because of a defective carbon carrier design.
There's no carbon carrier in the 10 speed designs.

pdlpsher1
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by pdlpsher1

I have read some people have had their X Dome getting stuck on the freehub. I don't know if this is a common problem or not. Here's a post by a user on BikeRumor.

"I have had 2 XX cassettes get stuck on a Mavic body. Luckily, the the LBS and SRAM waranted the first, but now the replacement is stuck. The concept of these machined out cassettes is interesting but the interface is worthless. I am hoping that the interface of the XX1 is an improvement as I would like to switch to that group soon."

by Weenie


RussellS
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by RussellS

kulivontot wrote:IMO, the SRAM cassette is a better buy. Lighter, about the same cost,


Same cost??? Performance Bike, a pretty big internet/mail-order parts supplier, has the 7900 cassette for $180 on sale and $250 MSRP. The SRAM XG 1090 Powerdome 10 speed cassette is priced at $335 and a MSRP of $335 too. The SRAM is not too far from being double the price.

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