26 February, 2009

Custom fabrication bits for the mtb

One of the nice things about being mechanically inclined, and also working with some talented machinists is that some options open up for fixing and customizing parts on the bike.

First, the background: my FSA Afterburner crank has been a bit of a sore issue since I got my 29er, as it did not turn out to be what I'd hoped for. It was priced similarly to the new XT cranks at the time, and since I was not running the stock triple rings on either I figured I'd give up the nice Shimano shift quality for the slightly narrower Q-factor that the Afterburners have (169mm, like XTR).

I installed some Middleburn 26t/36t rings with a Salsa ring-dinger outer guard and happily rode for the '08 season... mostly. The 26t had very little clearance with my chainstay and some occasional chainsuck was really doing some damage there. To prevent this from worsening I put a cheap Vuelta 24t ring on which solved that problem and turned out to be a very nice ring (shifted nicely, ran smooth), albeit a bit heavy.

The next problem was crunchy bearings. Typical of OEM outboard bearings. I popped the seals, cleaned them and regreased well, and have been running on those to this date. They're ok, but I feel that the plastic dust caps prevent a nice adjustment from being possible. Also, the preload bolt on these cranks is made of very soft aluminum and uses a 5 mm hex key instead of the splined tool that Shimano uses. The result is that even at the very low torque used, it feels like it will round out at any moment.

This brings us to the current situation ---> not really wanting to buy a new crank, and being fairly enginuitive, I have come up with solutions to the above problems:

  1. Preload bolt - solution: make the tool size larger so it is less prone to rounding out. I got some help opening the 5 mm hex to an 8 mm. A side benefit is a minor weight savings of a couple grams. Not bad for increased functionality and no cost.

  2. Bearings - there are a couple options here:
    a) buy new FSA cups (un-necessarily expensive, still crappy bearings)
    b) buy replacement bearings (the trouble here, is that Enduro only makes ceramic bearings to fit the FSA cranks because FSA decided to be silly and oversize their spindle by 0.05 mm or so compared to the Shimano/Race Face standard. This does not present interchangability issues with the plastic caps on the OEM cups, but with the larger Enduro bearings that fit directly on the spindle it won't work)
    c) the solution to (b): make the spindle fit Shimano spec bearings. Some 320 grit sandpaper then 1200 wet sanding, lots of elbow grease and a couple hours later I have a spindle that takes regular outboard bearings which I can get from Enduro for $12.

  3. a) Chainrings: I have decided I was not totally happy with the shift quality of the Middleburn 36t and the weight of the Vuelta 24t. I was going to get the 26/36 rings from the XT FC-M771 touring crank since they are matched and would shift best, but the 26t would have clearance issues, and they are not very light. Instead I will get 24t and 38t rings from Spécialités TA which are very nice, and though they are not matched 14t gap combined with my Shimano SLX compact (M667) front derailleur should shift well. (as a side note, though heavier than XT or XTR the M667 derailleur solves a tire clearance issue that regular derailleurs have with larger tires on my bike - it's convenient that I like to run a double ring setup). To account for the 24t ring, I will be buying 11-32 cassettes when I wear out my 11-34s, which will also save a bit of weight.

    Side note: in case it is not apparent, my reason for using this chainring setup is the inherently higher gearing of 29" wheels. My 29x2.25" rear tire diameter increases development by 1.115 versus a 26x2.0" tire, so 38t and 24t rings are equivalent to 42.4t and 26.8t respectively.

    b) Outer guard: to go with the TA rings, I did not want to use an outer guard because it will obscure the nice chainrings from view, and is not necessary with a front derailleur to retain the chain. I also did not want to use shorter chainring bolts alone because this would leave an ugly portion of the crank spider showing. The solution is to fabricate some very light and nice looking spacers for the spider tabs:

    I will update when these are done, probably in April when I am switching the bike over from winter training/Paris-Ancaster mode to the regular mtb mode with the new rings and custom bits.
So along with a nice looking crankset that should result from the new rings and spacers, I should also save quite a bit of weight in a few places, which along with some other initiatives (new grips, lighter chain and some bolt tuning) should make the bike over 1.1 lbs lighter than last year.

Stuff for sale

I will use this post as a resource for selling some cycling related items. That way I can direct people here for pictures and info to avoid typing it often. Items will be removed when they sell, and more may be added later. If you're reading and find yourself interested in something, drop me a line at jeff.moote@gmail.com

Pictures will be added for most of the below items when I get around to it...

Item: FSA OS-115 stem
Price: $60

110 mm length, 0°, weight: 153g
Used <1 season (mtb)

Item: Easton EA90 top-lock stem
Price: $60
90 mm length, ±10°, weight: 132g
Lightly used, about 1 month

Item: FSA Pro chainring
Price: $35
50t, 110 BCD (compact), weight: 101g
Lightly used <1 season

Item: Salsa chainring (silver)
Price: $35
39t, 110 BCD (compact), weight: 66g
Lightly used, about 1 month

Item: BBG cyclocross chainguard
Price: $14
42t max, 110 BCD (compact), weight: 52g
Used about 1 month, looks new

Item: FSA mountain bike triple chainrings
Price: $50
44/32/22t, 104/64 BCD, weight: 136g
Outer & middle used <6 months, 22t used for a couple rides only
These look great and shift well.

Item: Rennen Rollenlager singlespeed tensioner
Price: $40
the best tensioner available - bolts in place with derailleur hanger (no springs)

(another) new blog template

I was not totally pleased with the last template I implemented as of this post, so I had been searching for something better. The look you now see is what resulted - basically a free template from the web with a bunch of tweaking to make certain things appear in english and to tweak the layout a bit.

I may make subtle changes to the layout over time, but I think this template is ultimately what I will leave in place for the blog, as long as it exists in its current form.

23 February, 2009

Falling into place

Last Friday I took the day off work (since I had worked on Monday – Family Day in Ontario) and headed up to a friend’s place to train all weekend. It’s a lot easier to put in the hours with nobody to distract you and with the motivation of someone else to train with. Over three days we put in about 12 hours of training, with about 8 on the bikes plus a hike and ample stretching. Mission accomplished as far as getting lots of base in a short period of time. Entertainment was in the form of the ’09 Cross Worlds and Star Wars Episodes VI, I and II. The legs are doing pretty well and I’m able to crank out the same wattage at a lower heart rate than two weeks ago, which is good.

My focus right now is shifting to force development and muscular endurance, as I feel those are probably my biggest limiters and will take the longest to develop. Tempo rides and slow seated hill repeats will make up many of the workouts, with some easy spinning in between for endurance and recovery.

Racing plans are coming together and soon I will solidify my calendar a bit more. I’ll be sure to post here when I do.

14 February, 2009

Checking in

It's been awhile since a post, so I felt I should write something.

Not too much is going on right now, but I can feel the upcoming season looming. The new road machine is in the works and should be ready just in time for some better weather. In the mean time I'm riding the 29er with 38c touring tires for some road time, the same setup I plan to race for Paris-Ancaster.

The training plan kind of fell apart when some returning injuries had me off the bike when I didn't plan to be, so I'm back to getting ride time in when I can, but I'm trying to be smart with it. I have to be very careful at this time of year to avoid injury, as my body isn't as strong as my will to ride hard. That will come later, so I have to tell myself to back off and put in the miles right now. I got out for a great ride today on the roads which have pretty much dried up. I'm debating between another road ride, trails or rest tomorrow - the road is sounding pretty good at this point.

I'm very much looking forward to another year of mtb and especially cyclocross racing, and I will definitely be doing a couple road races also for the experience and training. I'm looking for some consistency through the mtb season and some good results in cross before I move up to the 1 pm race and again experience some humility. All in the name of improvement!

That's all for now. More to come around the bike show when the new ride is done, and after that it won't be long before the race reports start flowing...

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