Wednesday, May 18, 2011

More on the New Bike

As you may or may not know, I purchased a spiffy new Specialized Epic Expert Carbon 29er MTB from the folks at the Cycle Loft a couple weeks back. Over that time, though I haven't yet had the opportunity to race it, I've been able to ride it a number of times and have gotten in a couple of good, long, fast group rides on it. So far, so good and I really do like the bike. From the additional time in the saddle, I have some additional feedback and notes on the bike and it's evolutionary setup.

The handling on the bike is excellent. The wheelbase was actually shorter than my previous Specialized Epic and despite the bigger wheels, the bike handles crisply and cleanly in the tight technical stuff. The bottom bracket height is on par with that of my old Epic, which is to say on the low side for technical New England terrain but great for high speed, smooth trails. The big wheels carry momentum really, really well and float over bumps, roots and baby-heads that trig smaller wheels. The difference really is very perceivable.

There is, however, a noticeable difference in effort required to get these wheels moving vs. my old ones. I'm virtually positive that this is because the bikes stock 29er wheels, tires and tubes equate to a couple of additional pounds as compared to my previous, ultralight 26er wheelset. I have some ways to shed some rotational weight in mind such as the drastic step of moving to tubeless (yes, I still do and always have run tubes in my tires), lighter weight rotors and I may just upgrade to a different, lighter set of wheels all together if I can figure out just what those wheels would be. Specialized runs a standard 9mm x 100mm front QR hub but on the rear it runs a proprietary (as in only Specialized makes it) 12mm x 142mm Plus through axle. The Plus is that Specialized pushed the hub flanges out from center a few mm vs. a standard 142mm flange spacing, which is the same as a standard 135mm hub, in order to get a stiffer and stronger wheel. What this translates to is the freehub being a couple mm farther outboard on the 142mm Plus than the 142mm standard. The current wheelset has had a minor issue with the rear hub where by the axle locking nut loosened and allowed the axle nuts to self tighten against the bearings to the point where the rear wheel wouldn't spin. Firmly securing and adding Loctite on the locking nut seems to be holding it in place.

As I mentioned previously, I've made a number of modifications to the bike, beyond simple suspension setup and tuning, in order to make the flavor and feel more familiar to me. The first of these changes were to swap the Thomson 2 bolt layback seatpost (I only run two bolt posts because they almost never fail, unlike single bolt posts, and Thomson just plain work) and Thomson 120mm x zero rise stem over from my old bike. The stock cassette was a lower end Shimano 11-36 10spd which I switched to a Shimano XT 11-34 10spd I had in the parts bin which I'd planned to use for my tandem. I later swapped the alloy flat and super wide 685mm wide handlebars for my carbon Easton EC90 low rise bars, which are 235mm wide and the same as what I was using before on the old bike. I then swapped spacers from under the stem to above in order to compensate for the slight rise in the bars. The last change I've made thus far is to get a Specialized SWorks Captain 2.0 tire for the rear, which is a match to the front, in order to afford some additional traction. This came at a slight weight penalty over the stock, semi-slick Renegade 1.95 tire. The bike is now setup almost identically to my old bike and I like it, a lot.

The only real problem I've seen has been with the SRAM X-9 10spd rear trigger shifter, which is mated to an X-0 rear derailleur. It just isn't as smooth and the shifters are not as reliable as the old SRAM X-0 9spd that were on the old bike. Initially I had issues with a defective rear shifter, which the Cycle Loft took care of post haste by replacing with another new shifter. Unfortunately, an hour into the first ride on it, that one failed as well. Again the shop replaced it with a new one, which I now have a couple of rides on.

I've got to admit thought that despite some cleaning up of the casing and ferrules and making sure the cable is good, clean and kinkless, the rear shifting still has a much heavier throw on the downshift than the old X-0 or even the X-7 I have on another bike. I have a set of Gore Ride-On cables that I have considered switching to but I'm still not 100% confident in the reliability of the shifter. This is in part because I'd noticed that the downshift paddle wasn't springing back all that well when I had it on the stand this weekend. I'm thinking that I will switch over to 9spd with the new chain, cassette and X-0 twist shifters that I have in the parts bin. This would also shed some weight as the shifters are super light and the cassette is also lighter as well.

The real test will come this weekend, when the bike gets to see it's first round of competition. This will be at the Weeping Willow MTB race at Willowdale in Ipswich, MA. I did the race last year with pretty good results and although it was a very physically demanding race where you were constantly on the gas the whole time with little or no reprieve, it was an excellent course. Hopefully things will all go well this year. It has been raining all week as well so I'm hopeful that that comes to an end and that the conditions are reasonable. We will certainly see though and if nothing else, it will be the same thing for everyone.


Tyler E. said...

Re: the 142+ spacing. Only the flange spacing is proprietary to the Specialized set up. 142 X 12 is a Syntace developed open standard named X12 that you have plenty of options for. So you can chose a 142 spaced hub of your choice and lace any rim to it. You will need to adjust your rear der. accordingly, basically a few turns of a barrel adjuster and your limit screws. You won't be able to swap between the 142+ and 142 wheels without making this adjustment, but if you go with only 142 or 142+ hubs you'll be all set. Basically your choosing your cassette location.
There has been a lot of confusion regarding this 142+ stuff IMO, there are options out there beyond the 1500 carbon Rovals if you lose the + flange width. Hope, King, I9, Hadley, all make 142 spaced hubs.

CB2 said...

You could just take the Specialized hub and lace it to a lighter tubeless ready rim.

mkr said...

Right. My concern was simply how well the rear derail could handle the inboard travel required if I go with the 142/135 standard spacing. Specialized didn't spec a wider BB so the change would actually improve chainline, as you say, I'd just need to move the rear derail low limit in and readjust tension. I'm thinking about the Easton Haven wheelset as I can get them fairly reasonably. The I9 are nice as they can be converted to fit any format easily but they are HUGE money. The Roval I had before were the nicest wheels I'd ever owned but over the top expensive.

mkr said...

So far I'm not totally smitten with the Specialized rear hub. It is 32 hole and built 3x with Revo spokes on a fairly light DT tubeless ready rim with alloy nips so it would be hard to save more than maybe 50g on a rebuild. Will see after some more miles but the freehub sounds a little rough all ready and the axle nut lockup happening again in the wrong situation could lead to a bike wrapped around a tree :)

Hill Junkie said...

Even if you got your wagon wheels down to the same weight as your 26" wheels, they would still take about 25% more effort to wind them up. Inertia is proportional to radius^2. Rotors, which are so close to the axle, would contribute negligibly to this effect. Count them as ordinary bike weight.

Jonny Bold said...

You guys sound wicked smaht.
I found the range on my new 29er set up much too wide, it seems like TREK was trying to achieve the range of a triple on a 2x10. I have a 26/39 with 12/36 on the back. Do any of you run bigger chain rings on the front? It seems like it would be a lot more versatile with something like 28/40 on the front????

mkr said...

On my old 26er I ran 11-34 with a 22/32/44 and spent +95% of the time in the 44. So far, I'm finding the 39x11 with the big wheels to be plenty of gear. I run a 40T on my cross bikes with an 11 out back and find that fine also. On the low end the 26x34 seems fine. The only time I ever used my granny on the old bike was at Mt Snow Nats on that wicked steep section as you turned and headed upslope in earnest.