#1
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8 speed STI levers
I recall in an earlier thread a poster requested information on
replacing an 8 speed Shimano Ultegra STI lever. These are no longer manufactured - only 9 speed is available. His concern was the cost of an upgrade to a complete 9 speed setup and was quite happy with his 8 speed casette, front & read derailleur and so on. The general concensus was that his only option was the 8 speed Sora STI lever. I would like to suggest that you can use an 9 speed STI lever with an 8 speed cassette and rear & front derailleur set up with the following reasoning: It is the cable tension connecting the STI lever to the rear derailleur that governs the amount of travel associated with the rear derailleur for each click of the STI lever. Once you have adjusted the rear derailleur adjustment bolt to give the correct cable tension so that the chain moves from the 8th (top sprocket) to the 7th sprocket then everything should be ok. Each subsequent click of the lever will move the chain up to the next sprocket. When the chain reaches the 1st sprocket (lowest sprocket) you still in theory have one click left on the 9 speed STI lever. However you will not be able to click the lever as the rear derailleur is prevented from travelling any further by virtue of the inward adjustment bolt and this prevents you from using that extra 9th click. Now I have not verified this with a 9 speed STI/8 Speed cassette combination as I still only use 8 speed STI levers but I previously used an 8 speed SIS down tube lever with a 7 speed cassette using the same principle without any problems. Can anyone suggest why my theory on 9 speed STI/8 speed cassette would not work ? R |
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#2
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8 speed STI levers
It will work okay with the 7/8 spd combo as the spacing between the
individual gears on the cassette is the same (the 8-spd cassette is one gear wider) but not an 8/9 combo as the spacing is smaller with the 9 spd. Basically the 8-spd cassette and 9-spd cassettes are the same width, it's just the spacing between gears which differs - this is why the 9 spd chain is narrower etc etc. The 9 spd STI levers are designed to index the smaller distance between gears. It's a pain but that's life....!! FWIW - you an use many 8-spd components with 9-spd set-ups but not the STIs. Boz "Rik O'Shea" wrote in message om... I recall in an earlier thread a poster requested information on replacing an 8 speed Shimano Ultegra STI lever. These are no longer manufactured - only 9 speed is available. His concern was the cost of an upgrade to a complete 9 speed setup and was quite happy with his 8 speed casette, front & read derailleur and so on. The general concensus was that his only option was the 8 speed Sora STI lever. I would like to suggest that you can use an 9 speed STI lever with an 8 speed cassette and rear & front derailleur set up with the following reasoning: It is the cable tension connecting the STI lever to the rear derailleur that governs the amount of travel associated with the rear derailleur for each click of the STI lever. Once you have adjusted the rear derailleur adjustment bolt to give the correct cable tension so that the chain moves from the 8th (top sprocket) to the 7th sprocket then everything should be ok. Each subsequent click of the lever will move the chain up to the next sprocket. When the chain reaches the 1st sprocket (lowest sprocket) you still in theory have one click left on the 9 speed STI lever. However you will not be able to click the lever as the rear derailleur is prevented from travelling any further by virtue of the inward adjustment bolt and this prevents you from using that extra 9th click. Now I have not verified this with a 9 speed STI/8 Speed cassette combination as I still only use 8 speed STI levers but I previously used an 8 speed SIS down tube lever with a 7 speed cassette using the same principle without any problems. Can anyone suggest why my theory on 9 speed STI/8 speed cassette would not work ? R |
#3
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8 speed STI levers
Rik O'Shea wrote:
It is the cable tension connecting the STI lever to the rear derailleur that governs the amount of travel associated with the rear derailleur for each click of the STI lever. No it's not. It is the ratchet or cam or whatever mechanism is used inside the shifter that governs the amount of cable pulled per click. Altering cable tension only tunes the position of the derailleur. It doesn't alter the amount it moves per click. So even if you get it in the correct position for one gear, it will be out with the next click. 9-speed spacing is different to 8-speed so either different shifters are required or some alternative solution. It can't be done simply by adjusting the cable. ~PB |
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8 speed STI levers
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#5
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8 speed STI levers
"Rik O'Shea" wrote in message om... I recall in an earlier thread a poster requested information on replacing an 8 speed Shimano Ultegra STI lever. These are no longer manufactured - only 9 speed is available. His concern was the cost of an upgrade to a complete 9 speed setup and was quite happy with his 8 speed casette, front & read derailleur and so on. The general concensus was that his only option was the 8 speed Sora STI lever. You don't need a "complete 9 speed setup." The derailers work the same. All you need is a 9sp shifter, a 9sp cassette, and a 9sp chain. The shifter is the expensive part. When it comes time to replace a shifter, spend the extra 30-40 bucks for a 9sp cassette/chain at the same time, and be done with it. I would like to suggest that you can use an 9 speed STI lever with an 8 speed cassette and rear & front derailleur set up with the following reasoning: It is the cable tension connecting the STI lever to the rear derailleur that governs the amount of travel associated with the rear derailleur for each click of the STI lever. Once you have adjusted the rear derailleur adjustment bolt to give the correct cable tension so that the chain moves from the 8th (top sprocket) to the 7th sprocket then everything should be ok. Each subsequent click of the lever will move the chain up to the next sprocket. When the chain reaches the 1st sprocket (lowest sprocket) you still in theory have one click left on the 9 speed STI lever. However you will not be able to click the lever as the rear derailleur is prevented from travelling any further by virtue of the inward adjustment bolt and this prevents you from using that extra 9th click. Now I have not verified this with a 9 speed STI/8 Speed cassette combination as I still only use 8 speed STI levers but I previously used an 8 speed SIS down tube lever with a 7 speed cassette using the same principle without any problems. Can anyone suggest why my theory on 9 speed STI/8 speed cassette would not work ? It very well might, but there's usually no reason to do it. People ran 7sp cassettes with 8sp setups because 8sp cassettes wouldn't fit on 7sp wheels. But 8sp and 9sp wheels are the same. If you have an 8sp wheel you can just slap on a 9sp cassette and have everything work perfectly. Cassettes are available as cheap as $15-16. Shimano HG50, and SRAM cassettes work just fine. Nashbar/Performance usually have a few on sale, and package deals with chains as well. Matt O. |
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8 speed STI levers
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#8
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8 speed STI levers
The space between the center of each sprocket is more or less the same for 7 and 8 speed,
but for 9 speed, it certainly is less. You cannot use a 9 speed STI lever with an 8 speed cassette using your example. Dave |
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