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  1. #1
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    Changing gear questions

    I was wondering if there are particular situations when you're better off switching the front or rear gears to change speed? I normally change the front gear speed when I want a big speed change rapidly such as if I'm on flat pavement and a sudden steep hill appears, and change the rear gear for more subtle changes like a slight change in the path's inclination.

    Am I using them right?

    Thanks

  2. #2
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    Not necessarily right. Every chainring is supposed to work with 5 rear cogs - the big chainring with 5 smallest cogs and so on (provided, you have 9 gears in the rear). Chain crossing is not a good idea.

  3. #3
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    What's chain crossing? And this is the first time I hear of this, you mean if I'm on a certain gear on the front I shouldn't use certain gears on the back? Is that why my chain sometimes rubs against the front derailleur?

    So which gears work with which?

  4. #4
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    I mean, using, say, the big chainring with big rear cog. Then the chain may rub against the FD cage.
    Yes, the more straight the chain line is, the better. That is, you will be better off, using the middle ring with 4-5 middle cogs, big ring with 4-5 smaller cogs and the small ring with 4-5 larger cogs in the rear. Otherwise, you may have problems with shifting, and the rings get worn out much faster.
    Edit: I am sorry, I forgot the right English term - it is rather "cross-chaining", or "cross-gearing", but I hope, you got the idea anyway. My bad.

  5. #5
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    each chainring uses a proportion of the rear cassette. the large chainring will use the smallest 3rd of the cassette, the middle chainring the middle 3rd and the smallest chainring the largest 3rd, this way you will avoid stressing the chain by bending it laterally or against the links, this is "chain crossing".
    you may find there are situations where you will need to change, say, to a smaller chainring while simultanoeusly changing to a larger cog on the cassette.

  6. #6
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    Thanks I had no idea. So when a bike is advertised as 24 or 27 speeds it's not really true?

  7. #7
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    Quote Originally Posted by ch2s
    Thanks I had no idea. So when a bike is advertised as 24 or 27 speeds it's not really true?
    In terms of pure maths it is true, 3 in the front multiplied by 9 in the rear makes 27 in theory. But actually, some combinations give you the same ratio, and others are not desirable - I mean, the cross-chaining. I actually use some 10-12 combinations out of 24 available.

  8. #8
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    I always thought that some combinations would be the same or very similar. Which two combinations would give the same ratio for example if you don't mind? I guess I could figure it out but I don't feel like doing maths right now and don't know by hart the number of teeth on each gear.

  9. #9
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    I didn't know about the large ring using the smallest rear & so on. I stick to the smallest ring in the front with cog 2-4 on the rear when I'm on trails. 1:2 on most climbs, 1:4 when I'm on the bottom trail.

    Not too long ago I found out you have to hold the shifter in when you upshift for the front. That isn't mentioned in the bike manual or anywhere else! I thought my gears were out of whack. Obviously this is my first geared bike...

    What riding conditions would you use the largest front ring for?!? Seems totally unnecessary to me as far as mountain bikes are concerned.

    thanks!

  10. #10
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    What do you mean by hold the shifter in when you upshift? What kind of shifters do you use?

    And about the large chanring when I'm on road I'm always on the largest chainring and almost always on the smallest rear gear (hardest possible combination) or just 1-2 up on the rear gears if I'm getting tired (I often even go up hills on road on the hardest possible combination).

  11. #11
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    I have Sram shifters. When I upshift from smallest to middle ring, I have to hold the shifter in until chain makes it up. It isn't near-instant like the rear. It was just me being a newbie learning that..

  12. #12
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    Someone correct me if I'm wrong but it sounds like your shifter needs to be adjusted, the cable may have stretched which is normal and can cause exactly that type of shifting problem. Your LBS normally offers free tune ups for a while after you buy the bike, maybe you should get them checked or adjust them yourself if you know how because it really sounds like it's out of alignment to me.

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    If you're not supposed to use all the gears on the cassette with the center ring then what's a 1x9?

    Bob

  14. #14
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    Mathematically its a 1 X 9. Really only a 1 X 3 though

  15. #15
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    I have the same problem as bitewerks but with Shamino Deore. I think my problem is I am trying to shift from the small sproket to the middle while in 1st gear. I did notice that it does shift better when I shift the front while in 3 or 4 gear. I had taken the bike back twice to the bike shop and still felt it wasn't right. At what point on the hill do you make the shift from the Granny to the middle chainring?

    Millman

  16. #16
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    this is an awesome subject... i didn't know this either but it makes sense... i always thought that there is something wrong with the bike when i used to do cross-chaining and i would hear the chain touch w/e metal part

  17. #17
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    Another website I read advises using only the biggest three cogs (ie lowest gears) with the granny gear, any cog with the middle chainring, and only the smallest three cogs with the big chainring. That seems to work just fine. I rarely used the largest 3 cogs before but now I use the whole range when I'm on the middle ring, rather than changing gear using the front derailleur.

    Bear in mind also that big cogs spread force more evenly as they're engaging the chain with more teeth, so using the full range of your cassette rather than just the smallest ones helps to even out and reduce the wear and prolong the useful life of your cassette.

  18. #18
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    Quote Originally Posted by ch2s
    Someone correct me if I'm wrong but it sounds like your shifter needs to be adjusted, the cable may have stretched which is normal and can cause exactly that type of shifting problem. Your LBS normally offers free tune ups for a while after you buy the bike, maybe you should get them checked or adjust them yourself if you know how because it really sounds like it's out of alignment to me.
    Generally speaking, it is right, the gears should shift seamlessly, if tuned up properly, In reality, there may be other problems, like derailleur hanger bent a bit (yet not enough to justify replacement), or sprockets of cassette not in ideal condition. So it is not always possible to get it perfectly right. Then you usually can tune the cable tension so, that shifting up will be very good, but shifting down won't, or vice versa.
    Also, cables may rub against housings. The housings may be damaged, particularly if you have the cables routed under the downtube and full length housings. I lube the points, where the cables enter housings, with some dry lube (like Pedro's Ice Wax, but any dry lube will do, I think).

  19. #19
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    Quote Originally Posted by ch2s
    I was wondering if there are particular situations when you're better off switching the front or rear gears to change speed? I normally change the front gear speed when I want a big speed change rapidly such as if I'm on flat pavement and a sudden steep hill appears, and change the rear gear for more subtle changes like a slight change in the path's inclination.

    Am I using them right?

    Thanks
    I don't know where some of the info in this thread is coming from, but you can use all the gears in the rear with the center ring. Otherwise, 1x9 and 2x9 would not work.

  20. #20
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    I had all the gears adjusted a few days ago. I broke the front shifter in a crash & the LBS replaced it. Still shifts the same way but I keep it on the small ring all the time for trail riding. It's just easier that way. I rarely ride in the streets. If I ever need a new crank, I'm going w/2 rings & bashguard.

    Anyone know if some shifters are built stronger to withstand abuse & crashes? Seems like that's a pretty likely component to get damaged... Thankfully, it was a free replacement for me!

  21. #21
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    Not sure whether to start a new thread or continue this one since the latter replies seem to describe the issue I'm having. Since I got my bike I've never ventured with the front shifter as I found that it didn't shift quite as nicely as the rear, so I'm wondering if I'm doing something wrong or is there something wrong with the front shifter. I always keep the front in the middle ring, but today I decided to experiment with the front so I downshifted to the leftmost ring. Everything was fine until I wanted to upshift back to the middle ring. While pedaling I upshifted the front, but the chain wouldn't catch to the middle ring so the shifter was on 2, but the chain was still on 1. This created this rattling noise that was quite annoying so I downshifted again to make the noise go away. This happened a few times before I was able to get back into the middle ring. I believe I was pedaling forward not too fast and not too slow, but the damn chain just wouldn't catch. My rear was not on the leftmost ring, but was on maybe the second or third to the left. Should I have moved it all the way to the left?

  22. #22
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    Quote Originally Posted by dimm0k
    Not sure whether to start a new thread or continue this one since the latter replies seem to describe the issue I'm having. Since I got my bike I've never ventured with the front shifter as I found that it didn't shift quite as nicely as the rear, so I'm wondering if I'm doing something wrong or is there something wrong with the front shifter. I always keep the front in the middle ring, but today I decided to experiment with the front so I downshifted to the leftmost ring. Everything was fine until I wanted to upshift back to the middle ring. While pedaling I upshifted the front, but the chain wouldn't catch to the middle ring so the shifter was on 2, but the chain was still on 1. This created this rattling noise that was quite annoying so I downshifted again to make the noise go away. This happened a few times before I was able to get back into the middle ring. I believe I was pedaling forward not too fast and not too slow, but the damn chain just wouldn't catch. My rear was not on the leftmost ring, but was on maybe the second or third to the left. Should I have moved it all the way to the left?
    Depending on what shifter you have, sometimes you need to push the shifter a little past where it clicks, until the chain catches, then let off.

    Do a search on how to set up a front derailleur.

  23. #23
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    It sounds like your cable is probably stretched or the derailleur isn't properly calibrated.

  24. #24
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    Quote Originally Posted by bitewerks
    Anyone know if some shifters are built stronger to withstand abuse & crashes? Seems like that's a pretty likely component to get damaged... Thankfully, it was a free replacement for me!
    Did the same with my SRAM X-5's. Given that they are plastic, I don't see how they won't break in the right crash situation. Easy solution is not to wreck. Cheaper too.

    Far as the gear question - it took me a while to get the hang of smooth shifting and the right gear combinations. I don't ever use my smallest chainring and rarely use my largest. There are 5 combos on my middle that i use almost exclusively. Even now my largest chainring shifts a little weird, it takes just the right amount of speed and torque (or lack of it) for my chain to jump to the largest.

    Like everything else, it's about practice and experience.

  25. #25
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    Quote Originally Posted by kapusta
    Depending on what shifter you have, sometimes you need to push the shifter a little past where it clicks, until the chain catches, then let off.

    Do a search on how to set up a front derailleur.
    How do I know if I have a shifter that needs to work in that fashion? I have the SRAM X-4 shifters and the rear shifting works nicely... it's just the front that's misbehaving.

  26. #26
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    I think there are some good points here. When assembling bikes out of the box, most come with assembly directions. In those directions, the manufacturer usually recommends certain chainring-to-cog combinations, because it avoids cross-chaining, which will prolong the life of the chain. That doesn't mean that you HAVE to pair these certain combinations, only that it is recommended for overall efficiency. I cross-chain fairly frequently, but on climbs I usually stick to second gear in the first cog, and on the rest of the trail I cross-chain any different combination in the second chainring. Also, when it comes to chain rub it's usually a matter of deraileur height, cable tension, setting the top and bottom limits, and aligning the deraileur to be paralell with the chainrings.

  27. #27
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    Smaller gear in the back=harder to pedal
    smaller gear in the front=easier to pedal

    try to keep the chain straight- cross chaining is bad

  28. #28
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    Quote Originally Posted by ch2s View Post
    I was wondering if there are particular situations when you're better off switching the front or rear gears to change speed? I normally change the front gear speed when I want a big speed change rapidly such as if I'm on flat pavement and a sudden steep hill appears, and change the rear gear for more subtle changes like a slight change in the path's inclination.

    Am I using them right?

    Thanks
    It is very situational, but this is how I use my 3x9 (3 in the front , 9 in the back). 44,32,22 Tooth count and 11-34 cassette (11 on small cog, 34 on the big)

    Middle chain ring for most terrain. Level ground to moderate climbs and descents. Just about every ride starts in the middle chain ring and use all 9 rear cogs with the middle ring. I use the big ring for street riding or for fire road descents. Last ride I had smooth fire road descent and hit 25 mph using my big ring and small cog giving max speed. I also used the big ring on 15-18 mph single track descent to minimize chain slap. No pedaling needed, but the bigger ring and corresponding bigger rear cog tightens up the chain some as compared to middle ring and small rear cog. I tend you use only the smallest 5-6 cogs in the back to reduce cross chaining. I never use the big ring and my 34 tooth large cog. There to severe of an angle between the front and rear gears putting side load in the chain. Plus a 44 /34 ratio is nearly duplicated by 32/ 26 or 32/23 combo. These are using the middle ring middle cogs. Same applies to using a 22/11 combo. That is very similar to 32/17 ratio. This the main reason why you can choose to not use certain combinations that might cause cross chaining.

    Now.. Small ring... I use that for longer and tougher climbs. While I have the same exact gear ratio in my middle ring 32/34 = 22/23 the middle ring combo leaves me no place to drop a gear. The reason is the front derailuer works very poorly shifting under load. The rear does not work well under load either, but a slight pause and it will shift. The front will drag for 4-5 crank rotations and may never shift. So if I am on a long steep grinder of a climb I will use the small ring and smaller cog. So for example

    32/34 = Middle ring / 9 cog = So nowhere to go for more gearing other than big ring

    22/23 = small ring / 6 cog = I still have 3 more cogs in the rear to lower down to in case I need them at an easy turn.

    Once I finish the climb and start the descent I will change from the small ring to the middle ring bring the ratios up quickly for the higher speed stuff.

    The hardest parts are quick dips where the trail goes from descent to very steep up. If the path is smooth you can attempt to roll the up with momentum. Take the drop fast and hope you have enough speed to pull you most of the way up the hill in big gear (higher speed). You may need to stand and mash completed it. Or when it is really hard there might be turn at the bottom killing all your momentum. In these cases you need drop gears early and may over spin some parts have enough to make it over the top. I have also down shifted cogs in the back and pedaled a few turns while riding the brakes just to change gears to be ready for the climb out. If you need to put power down you rather not be having the derailuers trying to change gears as that increases the risk of breaking stuff. You want to already be in the right gear.
    Joe
    '18 Specialized Epic 29", 19' Vassago Optimus Ti SS 29", '19 Ibis Ripmo, XC, AM, blah blah blah.. I just ride.

  29. #29
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    Great thread, with all the different scenarios all my shifting questions were answered here , now I gotta put it on the pavement, thanks all

  30. #30
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    Quote Originally Posted by JoePAz View Post
    The hardest parts are quick dips where the trail goes from descent to very steep up. If the path is smooth you can attempt to roll the up with momentum. Take the drop fast and hope you have enough speed to pull you most of the way up the hill in big gear (higher speed). You may need to stand and mash completed it. Or when it is really hard there might be turn at the bottom killing all your momentum. In these cases you need drop gears early and may over spin some parts have enough to make it over the top. I have also down shifted cogs in the back and pedaled a few turns while riding the brakes just to change gears to be ready for the climb out. If you need to put power down you rather not be having the derailuers trying to change gears as that increases the risk of breaking stuff. You want to already be in the right gear.
    Great info in this thread. This last one in particular is interesting because one of the local trails I ride is exactly as this. I practically need to spin on the steep and pretty short uphills and then don't really have time to switch gears going down, but had I I might have been able to make it up the other hill.

    Either way I have yet to find a way to make it completely smooth lol.

  31. #31
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    Quote Originally Posted by ch2s View Post
    I was wondering if there are particular situations when you're better off switching the front or rear gears to change speed? I normally change the front gear speed when I want a big speed change rapidly such as if I'm on flat pavement and a sudden steep hill appears, and change the rear gear for more subtle changes like a slight change in the path's inclination.

    Am I using them right?

    Thanks
    Yup Pretty close shifting the front ring early to get into the right range...then trimming with the RD...

    Of course on the other hand...

    if you have a steep short gully to deal with...

    I put it in the big ring and small on the rear and blast down has fast as I can...then on the up hill I grab a handful of RD to get to lower and lower gears...

    No time to reliabley shift the front...Anyway I end up cross chained and able to clean the section....most I ride with can't get it clean, cause they either drop the chain trying to get into a lower front ring....or havn't blasted down fast enough to get up the other side.

  32. #32
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    very good point. Shifting while you are putting lots of power on the pedals could break your chain and/or derailluer
    Last edited by hocorider3700; 02-27-2013 at 05:26 PM.

  33. #33
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    Instead of focusing on putting power down between the ups and downs, shift into second and focus on lowering your center of gravity and picking the right line. You can start at a higher gear in the rear if you'd like, just be careful about peeling off gears. The only time I hammer a downhill in third is if it's a non-technical section and I know the next hill is short and steep. If you do that, attack early and mash the pedals. Select the right gear in the back and peel off as you get closer to cresting the hill and lose momentum.

  34. #34
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    Who knew...so much to learn...so there goes the saying "its easy as riding a bike"

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