talk to me about bicycle gear shifters/dereilleurs

Discussion in 'Shiny Things' started by shores, Jun 11, 2018.

  1. shores

    shores ElBandido

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    ps, i live in a small town with one bike shop with ridiculously overpriced bikes
    otherwise walmart/cdn tire is the only thing within about 3 hrs driving
    #21
  2. RVDan

    RVDan Long timer

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    I take care of a small fleet of Canadian Tire bikes belonging to a rental company. They're absolute crap but not hopeless.

    First take the wheels and crankset apart and grease the bearings and set correct preload.
    Then lubricate the hell out of the derailers.
    Then the tricky part. Pry those grip shifters apart and grease them internally. So far none of them have had anything in them, and a lot of them actually had the cable routed incorrectl. Yours might be better if they're the actual Shimano brand, I deal with the Chinese "Flower" and "Sunshine" brand names on these cheap bikes.
    Ive also had some really bad freewheels that had a serious amount of wobble in them causing a gear jump frequently. Spin the rear wheel forward while keeping the chain stationary and see how much the gears runout.
    Expect to replace some parts, but don't worry, parts are cheap, but you may have to drive to the next town.
    #22
  3. Gummee!

    Gummee! That's MR. Toothless

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    You need to define 'ridiculously overpriced' here.

    My definition of ridiculously overpriced starts at about $10k...

    M
    #23
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  4. Flipflop

    Flipflop Been here awhile

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    One of the more surprising things I've seen in a bicycle shop, is that the first time you drop a shitty bicycle and bend the derailleur hanger... Bending the derailleur hanger to align the derailleur isn't a terrible way to go about making an adjustment. Some of the more ham fisted folks start there and fine tune the cable adjustments. On cheap stuff, at times, the cable adjustment and spring tension serves no real useful purpose. Bulls have tits, and derailleurs have adjustment screws, not all of them work.

    On the real cheap stuff the cable length matters more than anything. They've got too soft of spring tension to do a damn thing other than make suggestions and get it into the ball field. Loosen up the clamp screw on the end and make sure the cable isn't set too short from the start and it will fully retract without trying to cross chain into the smallest cog.

    A lot of hardware stores carry chains, cables, and chain breakers... Cheap shit that is the right length, is better than good stuff installed wrong.

    You'll also never get the thing to shift right in the big ring unless they put a long enough chain on it to start with... and the front deraileur doesn't touch the chain once its up on the big ring. If it is touching then the driveline slack throws things all out of whack if you pedal out of the saddle up a hill. Touching it is already wanting to move the chain somewhere else... Loosen up, twist the clamp and adjust as needed. Up and down works on the tube too... Just make sure it has enough clearance not to hang up on the flat bar in the small ring. Sometimes the bottom brackets are the wrong width if you've got a cartridge style bottom bracket and there is no possible way to use the small ring on the front in any possible configuration.

    I like friction shifted bar end shifters or frame shifters just because you put it where it needs to go to be smooth. Indexed shifting is great if you spend a few hundred bucks, but the POS factor is high on anything below Shimano 105 hardware...
    #24
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  5. shores

    shores ElBandido

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    your idea and my idea are notwhere near each other
    i can see a few k if you race or ride a lot though
    #25
  6. Gummee!

    Gummee! That's MR. Toothless

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    You can get a great bike for $3-500. You don't HAVE to ride $6k bikes. ...or even $1k bikes.

    I'm willing to bet that that LBS has lower end bikes as well as the spendy stuff.

    M
    #26
  7. Flipflop

    Flipflop Been here awhile

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    Used, lower end bikes are where it is at for me...

    A $500 new machine for $200 used, is a bargain compared to a new one at $165.
    #27
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  8. shores

    shores ElBandido

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    they are brand name shimano but not sure what model
    will pull the specs tonight or tomorrow
    the chain came off while pedalling with the kid trailer, and wrapped around the frame on the outside (was in gear 6, smallest rear sprocket).
    i have to loosen the hub to get it off anyways, and will clean/lube the chain and check for kinks in it, and then check all the alignment of the gears with the adjustment nut, and then set the H and L limits on it.
    will take the shifters off and clean/dry lube them before i do all that.

    no sense getting it all setup and then remove the shifters to clean/lube and slap them on after aligning it all.

    could be cable is a bit loose or tight but doubt it, more likely alignment and/or cable is gimpy

    what's a good online place for good bike replacement parts?
    do you just cut the control cables to fit yourself with side cutters or get them professionally done?
    #28
  9. Gummee!

    Gummee! That's MR. Toothless

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    Sounds like your limit screws were off and/or the derailleur hanger was bent. Bent hangers are notorious for throwing chains off the ends of the sprockets. Limit screws are rarely right from the factory.

    Chains are cheap. Plan on replacing that one 'cause I'll bet there's a bent link.

    Sounds to me like you really do need a 'bike shop bike' if you're hauling around a trailer. Among other reasons: the brakes will actually stop you and the trailer.

    M
    #29
  10. DriveShaft

    DriveShaft Long timer

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    I generally walk into my lbs as often as I can, and throw things like wheel builds at 'em. But they so rarely stock components I'm interested in, and maintenance/shop equipment, so...I've a fair history of orders with Universal Cycles.
    #30
  11. High Country Herb

    High Country Herb Adventure Connoiseur

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    My definition of overpriced is $1000, so I get it. I think I can help a bit. I used to assemble cheapo department store bikes for a living, and ride middle of the range stuff myself. I buy my bikes used and unrideable and fix & tune them back to health.

    It sounds like the front derailleur is adjusted OK, but I think Gummee is right about the rear. Start by looking at it from the rear. The 2 cogs on the derailleur should be in a straight line with your rear sprocket. If they aren't, carefully bend them with your hand until they are.
    [​IMG]

    Next, there are two screws (limit adjusting screws) that limit the derailleur travel in both directions. Adjust those so the derailleur can't go far enough to pull the chain off the sprocket.
    [​IMG]

    Finally, pick a gear somewhere in the middle (front and rear sprockets), and adjust cable tension (cable barrel adjustment) until it is on the money. You may need to adjust tension slightly to get it to shift smoothly in both directions.

    As a footnote, some brands use different spacing between gears, so an indexed shifter from Shimano may not line up with a derailleur made by Suntour (that dates me, eh?). Also, shifters may be set up for a 6-speed sprocket, so may not work with a 7-speed, etc.
    #31
  12. High Country Herb

    High Country Herb Adventure Connoiseur

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    Interesting timing on this thread, as my wife just destroyed her shifter. She was changing rear gears, and the handlebar mounted ratchet shifter housing just shattered. We were many miles from our starting point, right in the middle of a homeless encampment in Sacramento. :lol3

    I was able to make it work by adjusting the cable to its extreme, placing the rear sprocket on a middle cog. This at least gave her a 3-speed bike with the use of the front derailleur. Meanwhile she talked to a homeless guy with a blind cat that rode on his handlebars. :nod You meet the nicest people on a...Giant mountain bike?

    So now I need to get her a new shifter...or maybe a whole new "groupset" (young people these days with their new fangled terms). Anyway, she has never quite figured out the 2 button rapid fire shifters.
    [​IMG]

    She has requested something more simple. I thought about the old single button indexed units like Huffy bikes have, but those are pretty crude.
    [​IMG]

    Maybe one step up from that?
    [​IMG]

    Maybe some grip shifters. Those may be the most intuitive for those who can't picture gear ratios in their head.
    [​IMG]

    Looking on Amazon, 90% of the shifters are SRAM brand these days. They have different index spacing, so I'd have to switch everything over. No thanks. I need to find Shimano shifters.

    I may just wait until I can talk to my old buddy Kevin in Merced. He has been running Kevin's Bikes since I was a teenager, and still looks the same age. I think he may be a robot. Whatever. Anything I need, he seems to have it in stock and be willing to explain it.
    #32
  13. Motomantra

    Motomantra Registered Lurker

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    Oh good, a drive train thread.

    My MB chain will skip sprocket teeth under higher load, as in steep uphill. Should I throw a chain on it first? When/how do I know when to replace the sprocket assm? Any thing else cause this besides the chain/sprocket?
    #33
  14. clintnz

    clintnz Trans-Global Chook Chaser

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    Always skipping on the same front chainring? Yeah, you should do that cog plus a chain at least. Sometimes on the back some gears can be replaced separately but usually the higher ones so if the problem is there you probably need the whole cluster, chain & any worn front sprockets. Usually you can compare wear between the most & least used chainrings to get an idea of how shagged they are. (Check through the drivetrain tuning guide linked above too)

    No. Not side cutters on the cable housing, you'll crush it. I trim them with a cutoff wheel in the angle grinder then ream the liner with a little drill bit. Cable kits are pretty cheap, or good bike shops will have all the bits in bulk & will cut to match your old cables. If you are in a corrosion prone environment get stainless steel.

    Cheers
    Clint
    #34
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  15. shores

    shores ElBandido

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    Shifters are shimano revoshift with shimano tourney dereilleurs
    #35
  16. RVDan

    RVDan Long timer

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    I don't buy online so I wouldn't know. My local bike store stocks everything, even old style friction shifters and ten speed freewheels.
    I have correct cable cutters if I need to trim a cable but usually I just take the bike to the shop and he measures and cuts them for no extra charge. It was $22 on the weekend for a full set of brake cables inner and outer with the 90 degree end adapter, rubber boots for at the brake and the crimp ends to keep the loose end from fraying.
    #36