Posted on 06/03/2022 7:46:41 AM PDT by Berlin_Freeper
Welcome to The Bicycle Thread. A monthly PING List for bicycle enthusiasts to share experiences, information and ideas.
Cycling season is now in full swing. We’ve just seen the Giro d’Italia & the next major is the Tour de France in July.
As for this humble cyclist, I’m doing a full-century ride this weekend in Brevard, North Carolina - the “WNC Flyer”. Just about a mile of climbs overall, but they’re concentrated in 2 sections at about 40 miles, and then again at 90 miles. Supposed to be perfect mountain weather, with temps in the low 60’s at the start, and mid-70’s at the finish.
Ride on!
Any bike mechanics out there? My bike has an issue where at certain points going up and down the cassette I have to shift twice, and then shifting often shifts two cogs going to a higher gear which I then have to shift back one cog. I have had the local bike shop work on it but they decided it is an issue with the frame.
Well, this week on a ride I was using the smaller chainring and noticed the rear derailleur shifted perfectly. When I shifted back to the large chainring the problem returned.
Has anyone ever heard of anything like this and can you tell me how to repair it?
Today is the day according to UPS that my new bike comes!!!
Could your derailleur be sticking at that spot and then pops too far? Lube the heck out it and see if this changes.
Take the chain off the derailleur and see if the movement is smooth.
Presumably the shifting had been fine, and then it got to its current condition. Have you changed out any parts in this time? Particularly, have you had a new chain, new shifter cables (assuming not electronic), new cassette? What group-set do you have?
The symptoms could be any of a number of things. I’d like to think the shop checked the easy stuff, and you should rule them out - but I’ve seen enough bad mechanics in shops to rule them out myself.
With shifting issues, the first things I usually check are the barrel-adjusters, making sure the rear derailleur pulleys are properly aligned with the cassette cogs. You don’t need any real expertise to try this out - just give a half-turn in one direction. If shifting improves, you’ve gone the right direction. If it’s worse, then go back to where it was, plus an additional half-turn in the other direction and try again.
Next I’d make sure I thoroughly cleaned the rear derailleur, and lube the pivot points with Tri-flo oil. Work the derailleur by hand to get the lube into the pivot points.
If you have one, use a chain gauge and determine how much the chain has “stretched” from use. They don’t really stretch, but they do wear, making them lengthen through time. A Park Tools gauge will tell you how far gone it is. I change my chain when the gauge says 50% gone.
Clean your cassette & chain thoroughly. The chain can be removed and you can then use a good de-greaser to get out all of the gunk. Then use a good lube that is specific to bike chains. Regular oils will attract and hold dirt & grit, causing shifting issues and premature chain wear.
The way the rear derailleur works is that the cable “pulls” the derailleur in one direction on the cassette, and the springs in the derailleur pull it back the other way when you shift the opposite direction. My recollection is that Shimano works in 1 direction, and SRAM works in the other direction - but maybe that was mountain bike gruppos. Regardless, figure out which way it’s going when you’re pulling in the cable, and which way when you’re letting out cable. If your shifting is good when pulling, and spotty or slow when letting it out, then it’s a good bet your shift-cable is ready for replacement.
The last 2 things are mechanical. The pulley-wheels in the derailleur (or “jockey wheels”) can have their bearings wear over time, and then get too wobbly. This allows the chain to stay on a track it shouldn’t (too much play in the bearings). Change them out - cheap, quick, easy. Also check the cassette itself and see if the cogs are worn. If the “teeth” are excessively rounded over, you’ll have all kinds of shifting problems, up and down. A rule of thumb is to change the cassette once for every 3 times you change the chain. That, of course, assumes you change the chain timely, as ignoring it will lead to pre-mature wear on the cassette & chain rings.
Pennies from Heaven X inflation
I used the mobile bicycle mechanic last year, reasonable rates.
I’m still thinking of putting an interrupter on the Surley LHT, for comfort.
I injured myself pretty good over Thanksgiving so I’m on the mend I should be on a bicycle maybe in July but it’s full-blown PT knee fest, and full recovery is a ways off.
But I am looking forward to peddling,it’ll be great exercise to incorporate into my PT routine.
Do you live in North Idaho? That’s where some amazing bike trails are located. Those are good, because they keep bikes off the roads.
Assuming you did not change your cranks or your bottom bracket, I will second chain wear, or cassette wear.
Thanks, that’s great advice. I got the feeling the bike shop didn’t really care about servicing my bike because I did not buy it from them. I am using older (ten speed) Shimano Ultegra components. I pretty routinely change the chain and usually change the cassette at the same time, and the bike shop changed the cables thinking that was the issue. But the pulleys on the derailleur are original, and the bike is ten years old.
This issue crept up on me and I didn’t notice how bad it was until I road my son’s bike and realized the shifting was much more assertive, and I found myself shifting more than I did on my bike.
I’ll take a look at the rear derailleur.
A few things to keep in mind:
- The derailleur springs can get weak with age, so won't pull as assertively on a 10-year old set.
- The jockey wheels are different top & bottom, so make sure when you get a set, you put them in the right spot. One allows more play (the one closest to the cassette) - this accommodates the lateral movement of the chain when shifting.
- A new cable will "stretch" over its first few rides. This may then require you to use the barrel adjuster to tighten it up again. Usually a half to 1-full turn is enough. You'll be turning the adjuster "out", effectively removing some slop from the cable.
- I didn't mention before, and again pretty basic for the shop if they tried any derailleur adjustments, but there is a small set-screw that keeps the top jockey wheel properly spaced from the cassette cogs. You'll have to screw this in (to push the pulley away from the cog) if it is riding on or too close to the cog. Of course, you'll un-screw a little if not close enough. There are some good YouTube videos that Park Tools put up on derailleur adjustments that might help you visualize better.
This deplorable family will be hitting Flatwoods Park if the weather cooperate. We might be getting a tropical storm tonight and tomorrow.
I haven’t ridden a bicycle in decades but my brother and I put many miles on our Columbia 26 inch one speeders we got for Christmas in 1962. Literally wore them out.
Panhandle?
Yep, Coeur d’Alene area.
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