Bicycle Mechanics - upgrading a 27 speed road bike

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chewyoreo
02-21-12, 07:36 PM
I currently have a 27-speed road bike - 3 chain rings on the crank, and an 8 speed cassette. Can the cassette be replaced with an 11 speed cassette so I can climb hills easier? However, will I not be able to pedal and ride faster because the smallest cog on an 11-speed cassette is the same size as the smallest cog on an 8-speed cassette? If the modification can be done, besides getting a bigger chain and different shifters, will any other modifications have to be made, too?
FastJake
02-21-12, 08:01 PM
1. 3x8 = 24
2. Only Campy currently makes 11S cassettes. Going this route would result in a complete drivetrain replacement.
To climb hills you don't want more gears. You want lower gears. You already have a triple which is a good start. Your options now are an 8S cassette with a larger-largest cog, or a smaller granny ring, or both. What is your setup now?
fietsbob
02-21-12, 08:20 PM
3x3x3? =27, too.
Delmarva
02-21-12, 09:08 PM
I currently have a 27-speed road bike - 3 chain rings on the crank, and an 8 speed cassette. Can the cassette be replaced with an 11 speed cassette so I can climb hills easier? However, will I not be able to pedal and ride faster because the smallest cog on an 11-speed cassette is the same size as the smallest cog on an 8-speed cassette? If the modification can be done, besides getting a bigger chain and different shifters, will any other modifications have to be made, too?
Don't bother with more gears...you have plenty now. Just get the widest range 8 speed cassette that your rear derailleur will handle. Your choices will likely be 30 to 34 teeth on the low end. What is the tooth count for the largest sprocket on the current cassette?
HillRider
02-22-12, 08:54 AM
3x3x3? =27, too.
Thank you for the arithmetic lesson. That was most helpful. :)
cycle_maven
02-22-12, 10:04 AM
I wouldn't upgrade an 8-speed drive train unless it was completely worn out and I had bad case of "upgradeitus". Best choice is to get a larger cassette for the rear and a mountain bike rear derailleur to handle the extra gear size. If that isn't enough, you can get a smaller inner ring for the crank, but a 30-32 or 30-34 ratio is enough to climb most anything.
fietsbob
02-22-12, 10:24 AM
I had built up a 3 speed, 3 cog cluster, on the Sturmey, and a triple crank ..
early 60's built based on my Puch-JCHiggins bike. all steel ..
27 speed. 3 friction levers a reliable bike, still on the 26 - 1 3/8 tires.
jimc101
02-22-12, 10:31 AM
Shimano Dura Ace will be 11 speed for 2013 (should be in the shops later this year) but with others, upgrading from 8-10/11 speed isn't that good on an idea, due to the need to replace so many parts.
You don't mention what cassette you are currently using, but you can get 11-28t 8 speed cassettes, and with the appropriate RD this should allow you to climb most hills especially as you have a triple up front.
chewyoreo, What brand of drivetrain do you have? Shimano? Compagnolo? SRAM? If other, what?
What is the tooth count on your largest and smallest chainring (front gears)? What is the tooth count on your largest and smallest cassette gears (rear gears)?
There are alot of bicycle gurus that can help, but more info is required.
Brad
Monster Pete
02-22-12, 02:01 PM
Wider range 8-speed cassette and/or smaller granny ring=job done. No need for increased complexity.
HillRider
02-22-12, 02:55 PM
Shimano Dura Ace will be 11 speed for 2013 (should be in the shops later this year)....
That's been in the rumor mill for awhile and has been confirmed from several sources recently.
What isn't certain is will the 11-speed cassettes fit on current 8/9/10-speed freehub bodies or will a new wider 11-speed design be needed. I believe the current conclusions are the 11-speed body will be wider but will take 8/9/10-speed cassettes with a spacer (sort of like 7 on an 8/9/10-body) but 11-speed cassettes won't work with earlier hubs.
So, will it be compatible with Campy 11-speed spacing? Could be but not real likely considering Shimano and Campy's refusal to be compatible with each other's drivetrains in the past. Jtek seems safe for a while.
Fietsbob just reminded me of when I was a young lad about 1960. One of the (slightly) older guys had a bike with a 4 speed Sturmey Archer,3 speed freewheel and triple crank. I believe he was on the lookout for a 2 speed bottom bracket (if such a thing existed). This was in the days before 5 speed freewheels were heard of. He only built it because he had a load of spare parts to play with - and because he could. Of course we all laughed like drains, after all who wanted more than 8 gears? What did we know? I can't remember if he cobbled bits together or found parts that fitted correctly (I doubt that), I must ask him next time I see him. Those were the days - real steel......
Delmarva
02-22-12, 08:36 PM
Fietsbob just reminded me of when I was a young lad about 1960. One of the (slightly) older guys had a bike with a 4 speed Sturmey Archer,3 speed freewheel and triple crank. I believe he was on the lookout for a 2 speed bottom bracket (if such a thing existed). This was in the days before 5 speed freewheels were heard of. He only built it because he had a load of spare parts to play with - and because he could. Of course we all laughed like drains, after all who wanted more than 8 gears? What did we know? I can't remember if he cobbled bits together or found parts that fitted correctly (I doubt that), I must ask him next time I see him. Those were the days - real steel......
Your story reminds me of the local bike shop in SoCal where I grew up in the early 1960's. The owner combined a 4 speed hub with the then exotic 5 speed free and 2 speed chain wheels. He built it for the challenge and never sold it. I was fascinated but remained satisfied with my Dunelt 10 speed.
HillRider
02-22-12, 09:08 PM
Combining an IGH with a freewheel/casette has been done commercially. Sachs (before their aquisition by SRAM) made a 3x7 hub that combined a 3-speed IGH with a freehub body that took a 7-speed cassette. Bike Friday fitted this hub to several of it's models along with a single chainring.
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