Welcome to our Ask a Mechanic column where our expert mechanic Daniel Slusser answers your bike maintenance questions. If you have a question for Daniel, please post it on our Facebook Wall or e-mail Daniel directly at firstname.lastname@example.org.
Question: I have read your article about the best bang for buck set up for Shimano XTR, I was wondering what would you suggest if I go the SRAM path? What would be the best shifter and rear derailleur combination for SRAM XO that would give me the best performance without the excessive cost? Thanks and more power to you. From: Jubei
Answer: Great question Jubei! Anyone who knows me will tell you that when it comes to mixing and matching components, nothing is sacred. While that approach may not yield the most cohesive looking complete build, it can really save you money while producing a bike that will perform nearly as well as one with a complete component group.
My recommendations for a budget XO 10-speed build are quite similar to my XTR recommendations. In general, good rear shifters are more important than good rear derailleurs and front shifter quality doesn’t matter out on the trail. What that means is that you should pop for the XO rear shifter for sure, it has higher quality, more precise internals, and an adjustable billet aluminum thumb shifter that you can orient in the ideal location for your hand position. Plus, they feel great, shift faster, and execute those shifts more reliably while offering better feedback to let you know when a shift has been properly executed. On a side note, XO 10-speed shifters were redesigned for 2014 and the newest shifter offers a marked improvement over the older 2013 model, that didn’t feel as precise as the XO 9-speed shifter it replaced.
Because all front shifters seem to work just as reliably as the others, X7 is the budget choice here. It won’t feel anywhere near as nice as the XO rear shifter, but it will work just as reliably and will never miss shift. Another benefit of going with an X7 front shifter is that if you decide to go 1×10 later, you didn’t shell out a bunch of coin on a shifter that will end up in the spare parts bin.
For a rear derailleur, I think you will find that the performance of the X9 unit offers 9/10ths of the performance available with the XO rear derailleur. The main difference is that the XO rear derailleur has cartridge bearing pulleys, lighter aluminum and titanium hardware (including a titanium spring) and a lighter carbon cage. Plenty of riders kill rear derailleurs on a regular basis, so spending a lot on a rear derailleur doesn’t make sense for these folks, which is one more reason to go with X9.
SRAM front derailleurs seem to perform at very similar level regardless of the group they are from. X7 would be my budget choice here, but with that said, there is very little difference in price between the various SRAM options, so I would probably go with an X9 front derailleur to match your rear derailleur. The X9 will only cost you $15 more.
For cranksets, the carbon arms found on the XO crankset are sweet, but cost nearly twice that of the X9 crank. Weight difference between the two is only about 60-70 grams depending on chainring configuration and a few of those grams can be had by switching to alloy inner chainring bolts. Two great features found on the X9 crankset are the hollow forged aluminum arms and replaceable spider. This replaceable spider makes it future proof for new bolt circles and makes it possible for aftermarket companies like NSB to make chainrings that work with it. So my pick for a budget crank is X9.
My experience with SRAM chains is that they are all great, but you do get a few more miles out of the higher end offerings, although SRAM does not make an XO branded chain. Even the cheapest 10-speed PC-1031 chain works wonderfully out on the trail and does an admirable job of remaining corrosion free. I feel that SRAM’s best value chain is the PC-1051 for its balance of price, performance, and longevity. But, there are deals to be had on SRAM PC-1091R chains that make going this route very attractive. In addition to the longer life offered by the PC-1091R you save 25 grams of rotational weight, and get slightly better shifting performance. Given the overall expense of a new group, spending another $25-30 on a great chain is worth it in my opinion.
Like the chain, there no XO branded cassettes, but the XG-1080 is the cassette from that level. This cassette is one serious piece of equipment that is certainly lust worthy, but it comes at a dear price. A downside of this cassette is that it has an alloy large cog to save weight. This cog will wear quicker than the all steel cogs found on the PG-1070. If you put in big miles and/or are a heavier rider, the PG-1070 is the obvious choice at far less than half the price of the PG-1080. However, if you are itching to spend the money you saved on your derailleurs, front shifter, and crankset by forgoing XO on a “go-fast” part, I would consider shelling out for the PG-1080. You will save over 120 grams of unsprung weight, and I like the gear spread a little better on the PG-1080. Instead of skipping from the 11-tooth to a 13-tooth like the PG-1070, the PG-1080 goes from 11 to 12 for a smoother transition. Lastly, the pinned construction makes the individual cogs stiffer, which results in better shifting.
To sum it all up my budget SRAM mountain group build consists of an XO rear shifter, X7 front shifter, an X9 front and an X9 rear derailleur, X9 crankset, a PC-1091R chain, and depending on your riding style, a PG-1080 cassette.