The Analyzer Presents: Top Fuel Diet Series – Cassette & Chain

One of my rules is “Don’t replace, upgrade”.  So when I was looking at some periodic maintenance of my drivetrain, I saw that as an opportunity to shave a little weight too.  Like many carbon bikes, the Trek Top Fuel 9.8 SL comes with middle of the road components in some areas to save a little cost, so there tends to be some weight to shave there.

The stock Cassette on the bike is the SRAM XG 1175, and like all SRAM XD 11 speed cassettes currently the range is 10-42t.  There are several compatible options in this range, but the main difference between the high end and mid to lower end cassettes is the construction.  Like the lower end cassettes, the XG 1175 is a pinned design, with each of the smaller cogs connecting to the adjacent cogs with pins.  A lot of pins.  One Hundred twenty three pins in fact.  Some people have issues with these pins creaking, fortunately I did not, but it is certainly not the most elegant design.  In this case, the largest 42t cog is aluminum and pressed onto the cassette, which saves a little weight.  Mine came in at 332g actual weight after nearly 2000 miles of use.  I will note that the overall condition of the cassette looks pretty good, probably aided by me staying on top of chain replacement when it was stretched beyond spec.  I’ll keep this cassette as a spare, for a backup set of wheels as it was surprisingly looking good.

As XG 1175  is a GX level cassette, looking at the higher ranges of cassettes like the XG 1195 and XG 1199 show a different construction method.  The first 10 cogs are machined from one piece of billet steel.  No pins, just one intricately machined piece of steel.  The largest cog is still aluminum and pressed onto the 2nd largest steel cog.  Looking into the different cassette options, I tried to figure out the differences between the top of the line XX1-level XG 1199 and the slightly less expensive X01-level XG 1195.  With the same listed weight and construction, it appears to me the only difference is that the XG 1199 has a raw finish on the steel cogs and the XG 1195 is finished in all black.  Since it weighed the same, I chose to save $40 and get the XG 1195.  Mine came in at 261g, a savings of 71g.  Not too bad, especially considering the cost difference over the XG 1175 is $65.

While I was changing out the cassette I went ahead and measured my SRAM PC1170 chain that I had replaced at the beginning of the summer.  One way to toast your entire drive train is letting the chain stretch out and not replacing it at regular intervals.  Once that chain gets long, it starts wearing everything it touches, putting slightly wider grooves in the system that it’s designed for.  All it takes is leaving a chain on for a few thousand miles once, and you’ll remember dropping $500 or more for a new cassette, chain rings, derailleur pulleys, and a chain.

Right now I use the Park Tool CC2 Chain Checker and it works well, though the cheaper Park Tool CC 3.2 does the same job for less.  Essentially it will tell you how much a fixed length of chain has stretched, with a guide of how far is too far.  One thing I try to do is pick up a spare chain when I see them on sale so that I’m not stuck on a trip or the night before a race scrambling to find an 11 speed chain at the last minute.  I had picked up a SRAM XX1 chain a while back so I went ahead and put it on with the new cassette.  Out of the box it was 259g, removing a few links got it down another 10g to 249g.  In comparison the old SRAM PC1170 was 242g, so slightly lighter, though that may vary from chain to chain as we’re only talking 7g difference here.  Both have worked well for me in the past, much better than other brands of chains which may be light but I’ve broken multiple times.  The chains look nearly identical, with solid plates and hollow pins on each, so I’m not sure what the purported difference is between the two different model numbers.  

Once I got it all buttoned back up I made sure my cable tension and limits were dialed and shifted through the gears.  The bike really had no issues before shifting, but now it was truly buttery smooth, rowing through the gears with instantaneous action.  Sweet!  Now this thing is race ready, and it did great at FSC round 1 at Hailes!

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