Jackshaft cassette wear and single cog replacement for shifter bike

Discussion in 'Transmission / Drivetrain' started by sactownie, Oct 21, 2013.

  1. sactownie

    sactownie Member

    Got my new motor a month ago and have put some serious miles on it in that time.
    Took a 23 mile ride over the weekend and near the end my main chain started jumping teeth from the worn chain.
    It started doing it in 8th gear (8 speed cassette) then started doing it also in gears 5-on down so I had to go slow in 4th gear to make my destination.
    I replaced the chain and it works perfect except for 8th gear. It was still jumping teeth. I took the cassette off and ground out the "hook" especially on the last tiny 11 tooth cog but it still does it sometimes in that gear.

    My question, is it possible to find a 11 tooth cog for shimano cassette anywhere or should I just pay the $20 for the full replacement?
    I'm thinking that only motor bikers wear out that last gear so shimano probably doesn't bother with a replacement for it?
     

  2. sactownie

    sactownie Member

    lol I ALLREADY TRIED LOCAL BIKE SHOP. they dont sale single cogs anymore since the 80s, they said everything made in china now china cheap, you buy whole cogs now!
    I guess im screwed i have to buy the whole thing the little 11 tooth cog is going to wear out every 500 miles
     
  3. Fabian

    Fabian Well-Known Member

    No one sells individual sprockets for cassettes. You have to purchase a complete replacement cassette just to get the precious 11 tooth, 12 tooth, 13 tooth sprockets.

    Generally the chain will start jumping teeth on the smaller cassette sprockets when chain wear reaches 80% or greater.
     
  4. sactownie

    sactownie Member

    yea this sucks. 11 tooth cog isnt going to last very long under 2 stroke power. so is everyone else with a shifter bike having the same problem???? I put maybe 200 miles on mine before is started skipping gears in 8th gear!
     
  5. Fabian

    Fabian Well-Known Member

    I use 9 speed chain (because my application has a specific requirement to use the narrower 9 speed chain width) and typically get 1,000 kilometers (600 miles) out of the right hand side drive chains and rear cassette when they measure in at 100% stretch, upon which i replace the right hand side chains and rear cassette with brand new items.

    I usually get around 3,000 kilometers (1,900 miles) out of the right hand side 9 tooth and 36 tooth and 48 tooth jackshaft sprockets, and get around 6,000 kilometers (3,700miles) out of the left hand side jackshaft and engine sprockets.

    I tend to haul a lot of weight towing bicycle trailers on unpaved tracks and bicycle trails, which adds significantly more chain and sprocket wear than the average person will experience.
     
    sactownie likes this.
  6. sactownie

    sactownie Member

    I guess I should have replaced the chain when i put the motor on it. I got the bike 2nd hand so who knows how the original owner rode/maintained it.
     
  7. sactownie

    sactownie Member

    The weight you pull is probably about = to what I weigh so I guess 600 miles per chain is about right what I got out of mine before it started jumping teeth. bike had very low miles on it when i got it but it was 13 years old.
    New problem i have now is the rear wheel has broken 4 spokes in 2 weeks.
    I have a decent wheel that the bike came with but it seems to be failing now trying to pull my weight and the torque of the motor is just to much i guess.
    Should I buy a different wheel or have the LBS rebuild mine for $100+?
     
  8. Fabian

    Fabian Well-Known Member

    I hear of people breaking spokes, but in 50,000 kilometers of riding (30,000 miles) the only time that i've broken spokes was is in the very early days, when the bike was suffering from repetitive chain suck issues; ripping out the rear derailleur, then sending it into the rear wheel; tearing out spokes in the process, actually, tearing up everything in the process; including the front derailleur as well.

    In every other mode of operation (over the last 49,000 kilometers), i have """never""" broken a spoke through torque or weight related issues, and i've been known to haul heavy loads.

    Interestingly, the original wheels were 'Quando', typically found on lower end mountain bikes, but the rear wheel and hub lasted just shy of the 50,000 kilometer mark, with the hardening wearing away on the internal axle bearing area.
    That particular wheel has been replaced with a lower end Shimano item (because it was a cheap buy at $50) and it is the very wheel you can see in the photos of my Heavy Haul thread.
    I can report that it has not broken a spoke.
     
    Last edited: Oct 23, 2013
  9. Uncle B

    Uncle B New Member

    Also make sure you keep them lubed! I had chain jumping and wear issues before I regularly lubricated everything.
     
  10. sactownie

    sactownie Member

    I was using dry type lubes on the chains. Since this happen I have gone to more conventional oil type messy lube. I couldn't see how the dry type was lubricating the cassette gears.
    I have found this 10 pack of 11 tooth cogs for 9 speed cassette on ebay. http://www.ebay.com/itm/NEW-Set-of-...Cassettes_Freewheels_Cogs&hash=item1c295b6846
    Does anyone see any reason this wouldn't work on an 8 speed cassette? They come out to about $1.60 a cog which isn't bad if you even had to replace it every 300 miles.

    As for my broken spokes, I believe I missed an important step when i replaced that 1st spoke. I didnt know you had to release tension on the surrounding spokes. Im going to try to sort that out today. haven't rode in a few days, needed a break from it LOL.
    If this dont work ill just purchase a 36 spoke wheel off ebay for $50 delivered and see how far that gets me.

    Oh and by the way I want to run a way bigger tire on the rear to cushion the bumps in the road, I was looking at the cst cyclops in a 26x2.4 size. I have chainstay clearance but looks like my jackshaft gear to engine output sprocket is going to interfere! what to do with that? put some spacers on it to shift the sprocket more to the left?
     
    Last edited: Oct 25, 2013
    Fabian likes this.
  11. KCvale

    KCvale Motorized Bicycle Vendor

    If I may make a recommendation...

    Just replace the wheel with an internally geared hub so you can use a nice HD 410 or even 415 drive chain that doesn't have to move from sprocket to sprocket laterally tearing itself up at least a little bit on every shift.

    Heck you can get a new 26" coaster brake 3-speed Shimano back wheel with the cable and shifter for like $50 and though the coaster brake is useless with a jackshaft you have your bikes dual V brakes which is why for many shifter builds especially 4-strokers I go with a steel 7-speed bike and swap the hub or whole wheel for an internal.

    [​IMG]

    Your bike is a fix but I routinely have the local bike shop I get my new bikes from let me swap out a 7 speeds whole system for an internal 3-speed for like $30 if I pull all the 7-speed stuff off and install the new wheel and shifter.

    I have the parts for my next Big Red 4-stroke 3-speed shifter sitting here waiting for it's turn in the build bay.

    [​IMG]

    Other than NuVinci's I have yet to see a trashed internal shifter and they are a joy to ride ;-}
     
  12. Fabian

    Fabian Well-Known Member

  13. sactownie

    sactownie Member

    So these 11 tooth should work for 8 speed since its the last cog on the set, correct?
     
  14. sactownie

    sactownie Member

    I Re-trued my wheel with stress relieving the spokes at the same time, took it for a ride, no broken spokes as of yet.
    I need a rear tire bad, its so bald i'm picking up little slow leaks from glass.
    Think ill scrap the 2.4 tire idea and try to find a 2.2. If i break a spoke with a 2.4 tire on there it will rub the chain stays for sure and ill have to lift and walk the bike home!
    I just wish i could find a slightly smaller tire for the same price as the cyclops ($34 delivered for 2 tires)
     
  15. Fabian

    Fabian Well-Known Member

    No it will not work properly because the centre to centre sprocket spacing is less on 9 speed cassettes, hence the reason why you need to run narrower 9 speed chain.

    My personal preference is to run 9 speed chain on an 8 speed cassette because the increased gap between the outer chain plates and adjacent larger sprocket reduces ghost shifts if the bike is in an off-road situation; bashing and crashing over obstacles at speed.

    I would like to get a bunch of 11, 12 and 13 tooth replacement sprockets for 8 speed cassette spacing.
     
  16. Fabian

    Fabian Well-Known Member

    The indexing of the shifter is calibrated to the centre to centre sprocket spacing of the cassette. So long as the rear derailleur and the shifter are of the same manufacturer and are designed for each other, the rear derailleur doesn't know that it is operating an 8 speed or 9 speed cassette.

    The individual sprocket width of 8 speed and 9 speed cassettes is virtually identical and virtually identical between SRAM and Shimano, so you can mix and match sprockets to make a custom cassette. You just need to use the correct spacers for the flat sprockets, however the smallest sprockets have a built in spacer, so you can't easily use those sprockets on an alternative cassette system.

    The width of the rollers on 8 speed and 9 speed chains are identical, but 9 speed chains have thinner side plates to make the chain narrower in it's overall width. For this reason you can use 9 speed chains on an 8 speed sprocket spacing but you can't use 8 speed chain on a 9 speed sprocket system.

    Single speed chain uses a roller width of 3.18mm or 1/8
    6 and 7 speed chain uses a roller width of 2.3mm or 3/32
    8 and 9 speed chain uses a roller width of 2.2mm or 11/128
    10 speed chain uses a roller width of 2.2mm or 11/128

    Single speed chain has an overall width of 8.8mm (determined by the pin length)
    6 and 7 speed chain has an overall width of 7.4mm (determined by the pin length)
    8 speed chain has an overall width of 7.2mm (determined by the pin length)
    9 speed chain has an overall width of 6.6mm (determined by the pin length)
    10 speed chain has an overall width of 5.9mm (determined by the pin length)



    Shimano 8-speed Centre to centre spacing = 4.8 mm
    ................................Sprocket thickness = 1.8 mm
    ...................................Spacer thickness = 3.0 mm

    SRAM 8-speed.....Centre to centre spacing = 4.8 mm
    ................................Sprocket thickness = 1.8 mm
    ...................................Spacer thickness = 3.0 mm




    Shimano 9-speed Centre to centre spacing =4.34 mm
    ...............................Sprocket thickness = 1.78 mm
    ..................................Spacer thickness = 2.56 mm

    SRAM 9-speed....Centre to centre spacing = 4.34 mm
    ...............................Sprocket thickness = 1.80 mm
    ..................................Spacer thickness = 2.54 mm



    It starts to get a bit messy with 11 speed chains.




    These spacers give you options.

    http://problemsolversbike.com/products/cassette_spacers
     
    Last edited: Oct 27, 2013
  17. sactownie

    sactownie Member

    good info on the cogs. Does anyone grind the hook off the worn ones to get some extra mileage out of them before replacing?
    I had pretty good success with the 11 tooth doing this, it skipped occasionally at first then i guess it kind of wore itself in with the new chain cause it doesn't skip teeth at all anymore.
    Really happy I don't have to spend money on new cogs right now so I found a tire and bought one.
    Walmart has this tire Hutchinson Lowrider 2.35 size for $16 when you purchase it online,
    http://www.walmart.com/ip/Hutchinson-Lowrider-26-Tire/20434424
    They sent me an email 2 hours later to go pick it up at the store. I believe I saved $10 on 1 tire doing it this way. I only got 1 so Im going to try it on the rear tomorrow and hopefully it doesnt interfere with the jack shaft sprocket, If it does Ill just run it on the front and find something a little smaller for the rear.
     
  18. sactownie

    sactownie Member

    You know I was considering this but it looked like the internal gear setups were way out of my price range. where do you get one for $50? I couldn't find any less then $125.

     
  19. KCvale

    KCvale Motorized Bicycle Vendor

    I'm sorry, around $100 with the shifter is about right and that is just the hub, that $50 or so I quoted is what I have worked out with the bicycle store around the corner.

    I have a long story about the Try Me Bicycle Shop but suffice it to say we have a symbiotic business relationship, I retail for a derailleur bike I intend to jackshaft and the parts to make it a 3-speed and they buy back all the shift parts on the brand new bike so my net extra is pretty low but it depends on the bike.

    The main reason for this is the dual V-brakes because with a shifter there is no coaster brake and most 3-speed beach cruisers don't have any front brake.

    There is a bicycle frame design for ya, a beach cruiser with 3-piece cranks, a 3-speed internal, and V-brakes or at least the bosses front and rear.
     
  20. sactownie

    sactownie Member

    I would like to have a beach cruiser type frame but I never seen any that look big enough for me. I am 6'4" 32 inseam. My bike I have now is actually a little to small for me if I were to ride it strictly pedal but works out fine for motorbiking.
    I just put the cruiser city type slick tires on it. they fit great but I only have 2-3mm clearance (correction, I only have about 1-2mm space) from the big gear on the jackshaft.
    As soon as I get a gear puller ill put some washer spacers on it to get it away from the tire, I tried to pull that gear off the jackshaft and it wont come off!
    Here is a pic of the tires on the bike, the ride is night and day, cant feel bumps at all and no more broken spokes but the bike does not take fast corners anymore is the only drawback. 2013bike.jpg
    tire2.jpg

     
    Last edited: Oct 29, 2013
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