Don't take me as a hater; I did the bike shop thing for 10 years, I am still one of their biggest advocates, andI run my own independent operation. However - unless you're one of the rare folks who frequents a bike shop staffed by cyborgs - the mechanics are human and even the good ones make mistakes from time to time. So, this post is not meant as a knock to bike shops; but a guide to help us all stay safe and comfortable.
Here's what I see most frequently:
- Handlebar and shifter position: I saw it again yesterday during a fitting with a new client. The bike had even been "fitted" and the bar was rotated down in such a fashion that I cannot see how he continued riding it as it was (which he isn't any longer; since we fixed it...) Check my post on this topic to learn how you can see if your bike has the same problem.
- Wheel Hub Adjustment: If they get adjusted at all... This is most often missed during assembly - as a lot of assemblies are paid by the bike and it's a seemingly harmless step to skip that can take quite a while on a tough wheel. When you remove your wheel from the frame, the axle should turn smoothly without any rough feeling and without any wobble or "play" which indicates looseness. Properly adjusted hubs not only turn easier and smoothly but will last longer with less maintenance.
- V-Brake Spring Setup (Mountain/Cyclocross Bikes): Also happens most often during assembly and can be missed or skipped in a tune up. The tension springs on the sides which pull the brake arm away from the rim are adjustable and often done wrong in order to center the brakes to the rim. I commonly see the springs tightened until the brakes are centered which results in brake levers that require more effort to engage the brakes and a "stiff" feel overall .
I find better results by backing off the spring tension from the side that is pulling too hard - even off both springs if necessary - to the point where the result is the least amount of spring tension needed to center the brakes. This results in a light and smooth lever feel with nicely centered brakes (which also tend to hold their adjustment longer).
- Derailleur Limit Screws: To be frank; if you find a mechanic who can get this right - stick with them. This skill seems to be getting more and more rare.
The limit screws are the two tiny screws on your derailleurs that determine - or limit - how far inward and outward your derailleur can travel during shifting. And, honestly, unless you know what you're doing you should never touch them. Improper adjustment can lead to damage of wheels, frame, or other components. I most commonly see the front ones improperly adjusted the back is just as susceptible.
Common symptoms are inability to shift to outermost or innermost gears or chronic shifting off the inside or outside of the gear cluster or chainrings. Poor shifting in general may be a symptom as a mechanic may use high cable tension to compensate for shifting off the gear cluster resulting in improper shift indexing (the derailleur won't line up with the gear correctly).
- Cable routing, adjustment, or general setup: Maybe I'm getting lazy for this last one; but this is sort of a catch-all for myriad other problems I see - and this isn't "Friday 8 or 9..."
~ Shift cables routed to the wrong side of the clamp bolt resulting in incorrect cable pull and poor shifting performance. There is usually a groove under the bolt where the cable should run.
~Cables run with a kink in them will result in excessive friction and sloppy performance in braking or shifting.
~Poor cable routing in the form of too much or too little cable housing increases friction as well. Too long of a cable run increases the amount of housing and the number of "curves" the cable must navigate and increases friction. Too short of a run steepens the radius of the curves in the housing and increases friction. Ideal: the fewest number of gentle and natural curves on the way to the clamp bolt.
~Wrong kind of housing used - most commonly seen when brake housing is used for shift cables. This results in sloppy and often sluggish performance. Brake housing has a radial winding you can usually see under the plastic outer coating while shift housing is linear and often appears perfectly smooth.
~Similar to what's mentioned in #4 above; cable tension that is set too high or too low to compensate for another set-up issue will result in poor shift indexing or braking that is either vague and sloppy or has no modulation.
Anything you've commonly seen done that you were relieved to finally have fixed? Tell us about it and leave a comment.