by Rush on Fri May 03, 2013 7:52 am
Well I've taken it out for a few short rides and it had its proper hit-out last Sunday.
It's funny the little things you notice first. One the short test rides one thing that immediately stuck with me was the sounds it makes were very different to my old bike. All those bigger tube diameters affect the acoustics a lot. There also appears to be a resonant frequency out of the saddle at about 28 km/h, and which point it sounds like the bar cages or rear derailleur are rattling loose.
The first long ride was cut short due to the seat post coming loose. I wasn't sure how much to tighten it and evidently it wasn't tight enough, so I had to stop every few kms on the way back and tighten it by the side of the road. I didn't want to overtighten it (first bike with a carbon seatpost!). Rang Darren and asked him about it and he said I should grease the collar and seat bolt and don't worry about over tightening it as the post and collar arrangement can take a fair amount of torque.
Started the 2nd ride with 5 N.m of torque on the post. This started slipping after about 15 km, so I tightened it as much as my small Allen key could and then it had no issues for the rest of the ride. I checked the torque when I got home and it was about 7 N.m.
In any case, the bike is ludicrously fast on the flats and on small inclines. The old bike always took a few pedal strokes to wind up and really get going, this bike responds with the first pedal stroke. The speed differential drops once the gradient approaches 10%, which you'd expect as by that point my body weight (I'm 88 kg) outweighs advantages in bike weight and stiffness. Although this also may be a technique issue as I'm also learning to use a compact crank for the first time. On my old bike, I'd run out of gears at about 7-8% so I'd become quite used at climbing out of the saddle for long periods. I'm beginning to find that I can sit and spin at gradients of 10% with this bike and I can ascend much faster.
The bike feels stronger and more secure on the descent as well. This is probably due to the stiffer front end than geometry, as the bottom bracket drop and wheelbase is almost the same as the old bike. The major geometry changes are the seat tube angle (73 vs 74-ish), longer chainstays (412 mm vs 400 ish) and shorter front centre.
This has a major affect on the bike fit, which is a very good thing as in late December last year I tweaked my neck at Kung Fu. Subsequent appointments with the physios have shown that I have very poor posture and I don't activate my deep neck flexors enough (quite common for tall guys apparently). It's highly likely that the old bike exacerbates this issue, as I have more weight on my hands and through my neck and shoulders due to the steeper seat tube angle. I'm also more stretched out when on the hoods. After about 4 hours on the old bike my shoulders and neck would become very painful.
With the new bike, my sit bones are much more stable on the saddle and my spine curvature is much better. My ribs are closer to my hips and its much easier to pull my chin closer to my chest and extend the back of my neck. Four hours on the Baum and my neck and shoulders are fine. I have some pain in my middle back, but this is due to my stiff back getting a nice stretch (I've always had a stiff middle back since I was a teenager).
Darren has said that one thing he takes a lot of pride in his bikes is a great fit. That after doing 8 hours in the saddle, you should be able to wake up the next morning, feel fresh and do it all again.
So the bike is a quantum leap, as well it should be! Ideas about bike design and construction have changed a lot in 20 years.
SRAM Force is quite nice so far. The upshifting (shifting to a higher gear) is fantastic compared to Shimano STi, the downshifting takes a bit of getting used to, especially with single downshifts. Making sure you are 'past the gate' on the ratchet takes a little while to adjust.
I think I've cut the rear brake housing too short near the rear brake, so I'll redo that again. I may redo the last bit of shifter housing on the rear derailleur as well, as Yokozuna supply a 340 mm section for this but everyone says that SRAM needs a longer loop. I've bought a new Yokozuna kit for my old bike and I'll cut off a longer section from that kit (it's the CX/Disc set) and put it on the Baum and see if it makes any difference. Some have suggested using the Shimano SP41 housing but I presume the Yokozuna housing is just as good.
If the sun comes out on the weekend I'll take some nice pictures.