morgothaod

I have a 21 speed MTB. The left grip is 1-3 and the right is 1-7. I was told to try to avoid combinations where the chain is like \ or /. So, I guess that means?

Left grip 1 Right grip 1, 2
Left grip 2 Right grip 3,4,5
Left grip 3 Right grip 6, 7

If I'm in Left grip 2 and I want to move to 3, should my right grip be on 5 or 6? Also if I'm in 3 with the left grip and when to go back to 2, should the right grip be on 5 or 6? A few times from switching from left grip 2 to 3 my chain briefly locks (With right grip being on 5 or 6).

I would also like to know the same thing for going from left grip 2 to 1.

Thanks!

General Geoff

You can use ALL available gears on the right grip if you're in gear 2 on the left.

Avoid using gear 6 or 7 when in left grip 1.
Avoid using gear 1 or 2 when in left grip 3.

All the other gear combinations should be fine.

CliffordK

I'd give yourself some more overlap.

Using your numbers:
Front 1 ==> Rear 1-5
Front Middle ==> Rear 2-6
Front 3 ==> Rear 3-7

So you just avoid the big-big and small-small combinations, and maybe 1 more gear over from that.

fietsbob

Trolling gear ..

suspend the bike see what the gear levers do ..


Basically They are called derailleurs because like derailing a train, you have to be moving to change gears ..

Lowest gear Ratio* is the smallest one on the crank, turning the largest one on the back wheel..

get the bike Moving, the pedals turning, then force the chain off the sprocket its on , to another one.


try pushing over a rail car that is standing still ..

*A gear ratio is Math.. tooth count front turns tooth count rear by simple multiplication.

a 40T chain ring turns the wheel twice if the rear cog has 20 teeth ... that is a 2:1 Ratio.

VegasTriker

The technical term for what you are describing is cross chaining. If your chain is binding while you are trying to change gears something is wrong and it may be more than just cross chaining. What usually happens if you are in the large chainring (outermost) and the largest rear cog (innermost), the chain may rub on the front derailleur cage and ditto for the reverse where you are in the smallest chainring and the smallest rear cog on the cassette. If the chain starts to bind in the first case the chain may be a bit too short. Your bike has decent drive train components so it is probably not poor components.

You are making this way too complicated. Just shift and if you end up with cross chaining, then you need to shift the front derailleur to a different chainring and then adjust the back. I'm lucky enough to have a beast that has a decent set of gears in the middle range (center chainring) and that is where I stay most of the time. There is no indicator on thumb shifters so I couldn't tell you what number gear I was in except that if feels right. When it doesn't because I am starting out from a stop or the terrain is changing, I change to a comfortable gear.

AlexCyclistRoch

Don't over-think it too much. You can pretty much use EVERY gear when the front derailleur is in the middle ring, and you really only need to avoid the large-large and the small-small combo on a 7-speed.

Looigi

Agree. Don't inordinately overthink it excessively too much .

Milton Keynes

When I bought my new bike, the manual just said to avoid gears 1 - 7 and 3 - 1. Probably not a bad idea to avoid 1 - 6 and 3 - 2 as well, but probably isn't going to hurt anything other than cause a little bit more wear on the chain.

Retro Grouch 

"Don't over-think it too much." That's what I think too.

Think of your left (front) gears as 3 ranges: one for uphill, one for the flats, and one for downhill. Within those gear ranges, use your right (rear) shifter to keep your feet spinning at a comfortable rate. That's pretty much all that you need to know. If you do it that way you'll seldom or never get yourself into the cross chaining combinations.