no, but you can get a 30 gear bike, which has a triple front chainring and a 10sp rear.
2007-10-11 14:38:57
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answer #1
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answered by funknuggets 2
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The term "21 speed" means that there are 21 different ways to combine one of your 3 front gears with one of your 7 back gears. The term "21 speed" is really just multiplication. It does not mean that you have 21 different combinations that you can use. First, some combinations are equivalent. The ratio of gear sizes for two different combinations could be either identical or so close that there is no practical difference. Second, not all combinations are really useable. You don't want to be using the largest (outside) front gear in combination with the largest (inside) rear gear. The chain is likely to rub against the derailleurs. You will get the same effective gear ratio without the rubbing by shifting the rear a couple of gears smaller and the front to the middle gear. In any case, this all becomes automatic as you ride more with your bike. Don't worry about it too much. HTH
2016-05-22 00:10:53
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answer #2
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answered by Anonymous
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It is not about adding an additional cog to the rear. That is not possible in a practical sense.
A bike shop would suggest replace either the rear cassette/freewheel (the whole cluster) with one that begins at 11t. (Most cheaper bikes begin at 13). That would give you a more challenging gear.
Or you would change out the chainrings on the front crank to one with a chainring(cog) with more teeth. If you have a 44t you would go with a 48t.
You can probably keep the shifters (those levers on your bars) the same.
My question to you (to comfirm you need to do this) is when you are in the "highest gear" is the chain on your bike rolling on the largest cog in front AND the smallest cog in rear.
You cannot have a 28-speed bike, if you have 3 rings in front. It has to be multiples of 3. 21, 24, 27, 30.
Good luck.
2007-10-11 15:41:17
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answer #3
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answered by ciaobella 3
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Having custom work done to put 4 gears up front would cost more than a new stock bike with a better set of gear ratios. When I switched from a compact gear set like yours to Ultegra, I was amazed at how many more "fast" gears became available to me. With the new gears, I am riding much faster now.
Get a bike with a 52 or 53 tooth outer chain ring. You'll be happy.
2007-10-12 01:44:40
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answer #4
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answered by intrepidfae 7
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You can have a 63 gear bike by using a 9 speed Rohloff rear hub with a 7 speed cassette. If you want to go to 189 gears then just add a triple front. The hub and cassette will cost you about $2000.00
Using a SRAM i3 hub with a 9 speed cassette and 3 chainrings will provide 81 gears. The hub and cassette will cost you about $300.00
However, this doesn't mean you won't run out of gears. You actually just need a cassette with smaller cogs and a crankset with larger chainrings. I bet you are riding a mountain bike of sorts... get a road bike.
2007-10-12 02:25:56
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answer #5
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answered by bikeworks 7
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the gears go 12, 16, 18, 21, 24, 27, 30 all depends on the rear gears (except 16 which is 2 main and 8 rear)
2007-10-12 02:00:27
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answer #6
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answered by G-T Rider 3
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Everything is possible . In Australia one company build touring trikes , (3 main gear) 9 in rear + Rohloff hub on top of it . This wide gear range set up works really well .
2007-10-11 15:58:20
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answer #7
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answered by Vladimir 3
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Nah... I don't think it's possible, or necesary.
You would need a new crankset and probably a new front deraileur. It's not just going to a metalshop and have them done for you and expect them to work pretty well.
What you could do is probably change your current chainrings to provide with a wider gearing. Or change your mountain cassette for a road one, if you're riding a mountain bike.
2007-10-11 14:55:54
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answer #8
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answered by Roberto 7
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Yeah they are not that common but here is one
http://www.davincitandems.com/images/drive2.jpg
Here is another that combined with a double chain ring will give four at the front. With a triple six !!!!
http://www.schlumpf.ch/sd_engl.htm
The easier and common solution would be to either install a larger chainring on the front (53 tooth is common) or a smaller cassette on the back.(Down to 11 teeth.)
2007-10-11 23:46:40
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answer #9
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answered by Glenn B 7
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Yes, anything is possible, they are more rare than other gear combos, but you could probably just go to a metal shop and get someone to machine another chain-wheel for you then you could go and get a bike pro to install it for you.
2007-10-11 14:43:10
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answer #10
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answered by worstedcdogg 3
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