[XRanger]

My sweet wife picked up a K2 EVO 4.0 bike at an annual bike swap for just under 600 $$. (She's bike crazy) She feels sorry for me because I've been riding a Schwinn MOAB hard tail for years. (Hey, I know...it's heavy, low tech and all but it works good and is consumately reliable.) Anyway, if you look at my attachment this K2 has a LOT of upgrades. It appears to have been well cared for but the cassette and free hub need replacing. Question: What cassette would you choose for this bike. Current one is a SRAM 11-34t. I'm considering the SRAM PG950 or the Schimano XT M770. There's good and bad press on both. I would appreciate any and all comments on my "new" bike. I've ridden it a bit and admit it's a whole lot easier ride than my old MOAB. I'm 70, super fit, do P90X every day and such so I can still be a kid on the hills but my knowledge base is in restoring antique auto's and such...not bikes. Thanks all. Cheers

 

[rlouder]

Congrats on the bike and welcome to mtbr.

There are subtle differences between cassettes, like the number of sprockets on the carriage, but the main difference is the weight. Either brand should work fine. An sram 970 usually doesn't cost much more than the 950 and is a good bit lighter. Don't know if you would notice the weight difference while riding.

 

[jeffj]

The SRAM 950 will work fine. They weigh about 340g for the 11-34 model where the SRAM 970 weighs about 305g. Slightly over an ounce of difference. You'll never feel that weight difference spinning so close to the center of the axle. Either one of those will be fine as would any number of Shimano 9 speed cassettes. The XT will be fairly light and the larger cogs are mounted to an aluminum spider which would be important if your freehub had an aluminum body, but the Shimano 475 has a steel freehub body so no harm will come from using a cassette without an aluminum spider to carry the larger cogs.

Here is a great deal on an 11-34 SRAM 950 cassette for $19.99:

http://wheelworld.com/product/sram-2008-pg-950-9-speed-cassette-32353-1.htm

or a Shimano HG-50 9 speed 11-34 for $21.99:

http://wheelworld.com/product/shimano-deore-9-speed-cassette-cs-hg50-4156.htm

Don't forget to get a new chain to go with your new cassette.

 

[Eville140]

The SRAM 950 11-32 weighs in at around 340.
The 11-34 version is a good bit heavier at close to 450.
I'm going to swap my 950 for a 970 whenever new wheel set time rolls around.

 

[XRanger]

The SRAM 950 11-32 weighs in at around 340.
The 11-34 version is a good bit heavier at close to 450.
I'm going to swap my 950 for a 970 whenever new wheel set time rolls around.

Thanks. The 970 sounds better to me. I think it has an aluminum spider and I need to replace the free hub also so whats the rule on hubs when using an aluminum cassettes versus steel?

 

[jpeters]

Nice bike maby some pics if you can.

 

[jeffj]

The SRAM 950 11-32 weighs in at around 340.
The 11-34 version is a good bit heavier at close to 450.
I'm going to swap my 950 for a 970 whenever new wheel set time rolls around.

Thanks. The 970 sounds better to me. I think it has an aluminum spider and I need to replace the free hub also so whats the rule on hubs when using an aluminum cassettes versus steel?

The pic above seems to disagree with Eville 140's claim.

Claimed weight of different SRAM cassettes (all in the 11-34 size):

PG-950: 382g
PG-970: 340g
PG-980: 304g

They will all work fine. The biggest nit I have to pick against the lower level SRAM cassettes is that the parts are 'loose' and while this makes cleaning easier to get everything super clean, you have to make sure all the parts/spacers go back together correctly. Not terribly difficult, but a little annoying to me.

As for Shimano, I have personally prematurely trashed three XT cassettes. I bent the 2nd gear cog on two of them and ripped four consecutive teeth from a cog on another. I am done with XT cassettes until major changes are made to them, but I am a good sized clyde. If you are of average size and strength, then XT should work fine for you.

I have had great luck with the LX (CS-M580) and the HG-61 from Shimano among others, just not a fan of XT for large/strong humans. I have also used several SRAM cassettes (950, 970 and 990) with no premature failures.

The SRAM 970 does not have an aluminum spider. See the pic below and you can see the separate cogs in the 'hole'. The 980 is the lowest level SRAM cassette that has an aluminum spider and the spider on the 980 has only the three largest cogs on the spider as opposed to the 990 which has a spider for the six largest cogs. The biggest benefit of an aluminum spider (aside from any weight saved) is that it will prevent damage to an aluminum freehub body from the cogs that are mounted to the spider. Shimano (the brand of the freehub the OP has) doesn't make any aluminum freehub bodies that I know of.

 

[Eville140]

Kinda depends on what year you have. Mine is close to 450 according to the post office scales.
http://weightweenies.starbike.com/listings/components.php?type=cassettes

 

[jeffj]

Kinda depends on what year you have. Mine is close to 450 according to the post office scales.
http://weightweenies.starbike.com/listings/components.php?type=cassettes

Quite possible.

SRAM could be trying to blow sunshine up our baggy shorts too. Hard to say for certain until you get one and put it on a scale you trust.

On the 'weight weenies' website, you see weights for the 11-34t PG-950 at anywhere from around 450g to as low as 386g.

Personally, I don't worry about the weight on my cassette a whole lot. It's not going to be any huge weight savings and it won't be noticeable when you ride your bike. I get the one that performs the best and lasts the longest for the riding I do at the lowest price I can find when I need it.

 

[XRanger]

Thanks guys. From what you have given me and a bit of searching I've pretty much settled on the SRAM PG990 and just getting a complete new Shimano FH M475 hub and canabalize what I want from it. (Price for the whole hub is less than just the free hub alone...go figure.)
I'll try to get a picture of the bike when it's back together.
Cheers.

 

[XRanger]

My wife has a super accurate gram scale. When I get my new cassette I will check it and post the results.

 

[jeffj]

Thanks guys. From what you have given me and a bit of searching I've pretty much settled on the SRAM PG990 and just getting a complete new Shimano FH M475 hub and canabalize what I want from it. (Price for the whole hub is less than just the free hub alone...go figure.)
I'll try to get a picture of the bike when it's back together.
Cheers.

I don't know how much you'll be paying for the 990 (excellent choice IMHO), but thought this was a pretty good price:

http://www.pricepoint.com/detail/13...ssettes/Sram-PG-990-Cassette-9-Speed-2010.htm

Just so you know (and in case you didn't), when you replace that freehub, you'll need to remove the bearing cone from at least one side of the axle which means you'll need to properly adjust the bearing cones when reassembling. Shimano has a bad habit of not tightening the jam nut to the cones tight enough so they don't come loose (especially on the drive side). Make sure you tighten those to each other pretty firmly. If you only remove the cone and jam nut on the non-drive to remove the axle to replace the freehub (which is possible), I would still tighten (very firmly) the drive side jam nut to the cone so it does not work itself loose in the future.

Also, make sure you snug the fixing bolt (the hollow bolt that attaches the freehub body to the hub shell) down pretty tight. It wouldn't hurt IMHO to put a little blue locktight on those threads. Ugly things can happen to your hub shell if that comes loose.

None of it is voodoo or rocket science, you just have to do it right.

Post back here if you want some more tips on that.