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Gears skipping under a load

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Gears skipping under a load
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flag scottvt
Posted: Oct 15, 2011 at 19:22 Quote
rolto1822 wrote:
scottvt wrote:
Another suggestion is that your chain is too short. When in the biggest cog in the rear, and obviously only one ring in the front is going to take up the most length of chain. When the bike is at rest, what does the rear derailleur look like? It is pointed towards the front of the bike at an extreme angle? If so, when your suspension compresses, (which will make your chainstays "grow") you need a little slack in the chain to make up for it. Put the chain in the big front big rear combo, take the rear shock off, and cycle the suspension, and see what happens.
Good point, was thinking that assuming its the original drivetrain though, it should have been properly set up at the shop. usually if it's loose enough to skip i'tll actually visually sag a bit compared to how it should look.
I suppose if it really is the original drivetrain, it could simply be worn out. But at the same time, we don't know if the previous owner wrenched on it himself or if a shop did the work. We don't really know for sure it is all original either.
flag rolto1822
O+
Posted: Oct 15, 2011 at 19:29 Quote
true - worth checking it out fo sho.
flag taskmgr
Posted: Oct 15, 2011 at 19:32 Quote
if you dont know.. take it to a bike shop. we can all take guesses i.e. could be cassette, the chain, both, or the front chainring. any of these can cause this and in lots off diff ways. could be as little as a bent cassette ring.
flag tortoracer
Posted: Oct 20, 2011 at 7:51 Quote
Thank you all for replies...I cleaned, lubed, and inspected it all. What I found was my chain might be a little stretched, the cassette has a few chipped teeth towards the higher gears, an I assume between the cable stretching under a load and the teeth, it is probably the cause.

For replacing the casette, what do I have to keep in mind when buying? If I only have one sprocket in the front, does it matter much if any teeth are chipped?
flag superbikes
Posted: Oct 20, 2011 at 8:01 Quote
keep in mind what cassette you allready have 9 speed 10 speed 11 /32 TEETH OR 11/34 TEETH . just check the numbers on your old cassette . if your front ring is single you might be ok but if i was going to get a new cassette and the front ring was damaged id get a new front ring . All will run nice and smooth then
flag rolto1822
O+
Posted: Oct 20, 2011 at 12:29 Quote
Yeah it depends how long it's been ridden with a stretched chain. Chipped teeth on the cassette isn't a good sign with regards to that. Take a good look at the front ring and see what you think - if you can, compare it to a good condition one (on a mates bike, or another of yours/parent's etc.) if you can. If in doubt, and you would rather do the work yourself, then i would replace it just in case. If you ended up not replacing it and it turned out also to be quite worn, you'll knacker the new chain and cassette out much quicker!
Note: you will need a few specialist tools for the cassette. Ideally a chain splitter as well. If it's a big ring you should be able to work that off the crank/rh pedal ok but if its the equivalent of a middle size then you'll probably have to take your pedal off (6/8mm alan key or pedal wrench depending on the pedal)
flag tortoracer
Posted: Oct 20, 2011 at 17:15 Quote
where are the numbers on the cassette? how much will this set me back in the end?

what tools will i need? if i need to go to a shop, any idea of an estimate?
flag rolto1822
O+
Posted: Oct 20, 2011 at 19:24 Quote
there may not be numbers printed on it but count the smallest and biggest rings (for number of teeth)
you'll need one of these
and one of these
flag scottvt
Posted: Oct 20, 2011 at 21:41 Quote
Yes to what rolto1822 said, but I would get the lock ring tool without the center guide pin so it will work with a bolted axle hub without having to remove the axle. Also you can find them for cheaper than that. I got a Park Tools one at my LBS for about $12 I believe. And if your really on a budget, but are determined to do it yourself, you could make your own chain whip with some spare chain and a piece of steel flat bar.
flag taskmgr
Posted: Oct 30, 2011 at 12:10 Quote
scottvt wrote:
Yes to what rolto1822 said, but I would get the lock ring tool without the center guide pin so it will work with a bolted axle hub without having to remove the axle. Also you can find them for cheaper than that. I got a Park Tools one at my LBS for about $12 I believe. And if your really on a budget, but are determined to do it yourself, you could make your own chain whip with some spare chain and a piece of steel flat bar.
old chain and vise grips work every time..
flag rolto1822
O+
Posted: Oct 30, 2011 at 14:32 Quote
but if you dont happen to have those things a vice grip will cost you just as much if not more than a basic chain whip lol
flag tortoracer
Posted: Oct 31, 2011 at 18:39 Quote
i have vice grips, and i could dig up an old chain probably, but its winter....im seeing this as pointless...how bad is it for a bike to stay outside under a roof, but with the very cold temperatures?
flag KEEPitSTUPID
Posted: Nov 2, 2011 at 5:54 Quote
Once your all built up check chain tension, put in the largest 2 gears, so chain is doing its maximum journey, the bottom jockey wheel should be forward about 45 degrees, similar point to made earlier, but is a noce rule of thumb, i had jumping gears after throwing on a new chain after i blew one up, and it was this tension that was wrong.

Get your bike inside! Nothing worse for a bike than a winter to look after itself.
flag rolto1822
O+
Posted: Nov 2, 2011 at 13:42 Quote
KEEPitSTUPID wrote:
Once your all built up check chain tension, put in the largest 2 gears, so chain is doing its maximum journey, the bottom jockey wheel should be forward about 45 degrees, similar point to made earlier, but is a noce rule of thumb, i had jumping gears after throwing on a new chain after i blew one up, and it was this tension that was wrong.

Get your bike inside! Nothing worse for a bike than a winter to look after itself.
correct in terms of the chain tension but he may need more slack (MAY) depending on the suspension and how it moves through its travel, which affects chain growth

 


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