Thursday, May 08, 2008

Similar, But Different

As you may recall, Jon and I have been working on the XT/X.9 comparative review for quite some time now. It hasn't been easy. For one thing, both groups work very, very well out of the box. So, we've been dragging it out, beating up the parts, waiting for something to fail. Nothing has.

For most of this time, Jon has had the X.9 and I have been thrashing the XT. Last month, that all changed, as I pulled the XT and shipped it to him, and he shipped me the X.9. I've now ridden the X.9 a little bit, and while the ends are the same--shifting, braking, getting power to the wheels--the means are different. Here are just a couple of examples.

Shifters:
Both of our review groups use a trigger-type shifter. Shimano does offer their integrated brake/shift levers, but we aren't using that one. SRAM, likewise, offers their Gripshift shifter, but, again, we aren't using that one either. The XT shifter uses a thumb paddle to shift to a lower gear and a trigger that can be operated by either your finger--pull--or thumb--push--to move to a higher gear. SRAM's shifter has two paddles as well, but both are thumb operated.

Brakes:
Both Shimano and SRAM use hydraulic brakes--Juicy 7's from SRAM and XT from Shimano. The Juicy's use brake fluid, while the XT's use mineral oil. There are some performance advantages to using brake fluid--like higher boiling point--but when it comes to maintenance, mineral oil is nicer to work with.

Cranks:
Both the TruVativ Stylo--SRAM--crank and Shimano's XT crank use oversize external bearings. The Shimano bottom bracket (BB) has three spacers, two for the drive side and one for the non-drive side. This allows it to accommodate two sizes of BB shells--68 and 73mm--as well as allowing extra space for an E-type front derailleur. The TruVativ has only two spacers, so it works with a 68mm BB and E-type derailleur or a 73mm BB, but is not compatible with a 73mm BB and an E-type derailleur.

Additionally, both have the BB spindle affixed to the drive-side crank arm, but their method of attaching the non-drive are distinctly different. The Stylo uses a modified ISIS attachment, while Shimano sticks with it's pinch bolt arrangement. Both work, but the Stylo looks a little cleaner.

I'm sure that stepping around patents has led to some of the differences seen here, but some of it has to be due to different schools of thought about how things should be done--how the rider interacts with the equipment and so forth. What this gives us, as consumers, is quite a bit of choice, both within the same company--Gripshift or triggers?--and from company to company. The fact that both systems are holding up to abuse shows that, at this level at least, it's hard to pick the wrong group.

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