1994 Burley Bossa Nova Gear change Qs???
My wife and I have been riding some long rides (ridden 115 and 85 milers after having the bike for 3 weeks) and have not had to dismount on any hill so far...We foresee that our adventures will take us above 2000 feet in elevation and would like a bit more climbing ability at the 4 mph speed. We currently have the stock Suntour XC Pro 12/28 freewheel cogs and front chainrings of 54/44/28. What are our best options for getting gearing on this vintage gear set? Ideas???
Our LBS mechanic says that we probably will need to change over completely to a Shimano cassette and if doing so will it make sense to change to a 8/9/10 speed cassette when doing so? Are there 11/30~32 or 12/30~32 Cogs available for this 7 speed vintage Suntour freewheel assembly? Does it make sense to do this with the old equipment or just change it all out for something new?
We are in NE Tacoma, WA.
I think you can pull stumps with a 28x28. I certainly can't imagine anything lower being of use.
Look on the Harris Cyclery web site. They are available. As an alternative you might also look at the chainring sizes. We regeared our tandem for more grunt and less speed on our 2000-ish Santana when we realized that we rarely used the large 52 tooth ring. I left the 12-32 8 speed cassette/rear derailer/front derailer in place and installed new chainrings (26-36-46) on the existing cranks. Much, much more useful for us in the hills and when hauling camping gear and we can still spin up to about 28 mph when conditions warrant. Any faster and we just coast. If you do change to a larger freewheel you'll probably have to spring for a new rear derailer with more capacity
pan y agua
Originally Posted by jgg3
well if your climbing something at 4mph, that gear puts your cadence in the 50's. I can see why you'd want to spin faster than 50rpm on a steep climb.
And I can think of a few climbs where 4mph is actually a pretty good clip.
I broke a tooth on my Suntour freewheel. When I tried to replace it I found that the spacing between the cogs was custom for my tandem. That spacing was no longer available. The cogs on the replacement freewheel were closer together. This required a new thinner chain. The new chain would skate/slip when changing chain rings. This required me to replace the cranks. The new cranks required new bottom brackets. I then found that the front derailleur wouldn't shift. It was too wide and would hit the crank before it pushed the chain onto the large chain ring. It had to be replaced. The cable for the old FD attached to the frame, the cable housing actually shifted the FD. I had to go to a junk bicycle shop to get a cable stop for the new FD.
We are at 12 28 and would love to have a 12/32 on that 7 speed. I will look into Harris and see what they have. Thank you very much.
We are total weight of 365~70 without bike and (I am 220 and used to be 270 with high BP) my wife is a great partner on the bike and really likes the activity. I had a complete ankle replacement and would like to spin more and apply less pressure to my appendage as I am not capable of standing up in the saddle like I once was. We are doing great and just want to have a bit more pleasure going up the big hills and not be dead by the top. We have no problem of going slow and geting there, but cannot handle just being totally depleted by the top and want to pull no stumps with my little tractor. We have our eyes on some 4000 elevation climbs and with living near the Cascades and Coastal range we have the opportunity to hit so many around the sound. We are having a great time doing this and I am just trying to get the proper tools for the job.
Please keep the thoughts coming.
I prefer to spin up hills. To climb long, steep hills like Mount Evans in Colorado on my single (7500 feet of climbing finishing at 14,100 or so), I switch the chainrings for 24-36-50 and the cassette to 12-27. This keeps the gear splits for RD shifts a little closer than with the wide-range cassettes. The stock Ultegra derailleurs handle that without difficulty, though it seems to me that I recall that I needed to avoid using the large-large combination owing to insufficient chain--I would just switch the chainrings and cogs w/o adjusting the chain length. I found plenty of use for the 27, 24, and 21 cogs on the inside of the cassette.
The nominal Shimano FD capacity is usually 22T. Lots of people stretch this some, with varying degrees of success.
It seems to me that you have about three choices worthy of consideration:
1) gear the tandem you have for your needs,
2) make more power to get the cadence up,
3) keep an eye out for a MTB tandem or frameset. Putting skinny tires on MTB rims can be a gear or more lower (about 10%) than the same size tire on a 700C rim.
Last edited by SDS; 05-22-08 at 06:49 PM.
Agree that lighter/smoother tires would increase climbing ability a bit. When present tires wear out get some lighter/smoother ones.
Check Bike Nashbar/Performance for older freewheels with larger gear range than you currently have if Harris Cyclery does not have what you want.
Agree, it's no fun to get on top of a hill/mountain totally exhasuted.
Sounds like U-2 you're doing great!
Pedal on TWOgether!
Rudy and Kay/zonatandem