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  1. #1
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    Downtube FS Gearing Upgrade Questions

    I’m new to cycling especially folders, I purchased a Downtube 8FS and have been commuting for 2 weeks now. I like the downtube but already feel the need to upgrade some components. My ride is between 8-10 miles a day and a little hilly. The gearing is useless (slips and is cheap)

    Not knowing much about bikes I was wondering if anyone could help me out…

    I want to upgrade the gears and was thinking of getting the following:

    1. SRAM PG-950 9-Speed Cassette (11-34)
    2. SRAM X.5 Rear Derailleur
    3. SRAM X.5 Trigger Shifters - 9-Speed
    4. SRAM PC971 Chain - 9 Speed

    I can get all this for around $150. Will this all fit a downtube FS? What else would I need to get?

    Can anyone recommend anything else? Should I upgrade with a crank crank set as well?

    Thanks

  2. #2
    The Legitimiser Sammyboy's Avatar
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    You could probably fit all of that, but a tune-up should solve the slipping. I'll make my apologies if you've already done this, but a bit of tweaking on the adjusters should get it shifting just right.

  3. #3
    Wheelsuck Fat Boy's Avatar
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    Your changes will make a _huge_ difference in the shifting and overall happyness of your bike. No amount of tweaking would help my bike to shift, ghost shift, skip, throw chains, etc. I would say that a crankset change will probably help life a little as well. The stock crankset is really crap. The stamped spider deflects like crazy if you try to put any torque on it. 175mm is your max on crank arm length, and that's a little too long, IMO.

    On my bike I changed the crankset to an FMF BMX crankset with a 53 tooth chainring. That gearing is actually a little tall, and I'm a reasonably good climber. A 50 would be about perfect. Everything else you have spec'd out is good stuff. While you're there, you might think about changing the derailler cable housing to something that is nicer. The stock stuff is pretty flexy.

    If you do these changes, you'll have a really nice folder. I know it seems like a lot of stuff to change over, but it makes the bike _so_ much nicer that you'll wonder why you didn't do it soon. Been there, done that.

    Once more I'll say for any Downtube prospective customers. The components are crap. Plan on replacing them as soon as you buy the bike. Sad, but true. When you put the rear derailler on, make sure the hanger isn't tweaked. If it is, bend it back straight.
    Austin doesn't have hippies. They have slightly rebellious Methodists. - Racer Ex

  4. #4
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    I'm no bike pro but I just got my Downtube 8H with the SA 8-speed hub and I have a similar distance commute and it's a dream. Being able to come to almost a complete stop while in 4/5th gear and to be able to shift down to first gear and pick right back up in an instant is such a nice benefit.

    I know they make a 3-speed SA hub, though I don't know if that would be enough gearing for you but I've found I barely ever go 4th gear on my flat route.

    I would highly recommend the SA on the Downtube.

    Aside from that I can't contribute much else, this is the first bike I've owned in many, many years So I'm not very knowledgeable with the gear mechanism.

  5. #5
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    [QUOTE=Fat Boy;6641410]On my bike I changed the crankset to an FMF BMX crankset with a 53 tooth chainring. QUOTE]

    Fat Boy can you direct me to any sites that supply the FMF crankset or simular at reasonable prices? What bottom bracket are you using?

    I'm thinking the SRAM x.7 now cause the x.5 looks a big long.

    I like my downtube and expected the parts to be not so great, i didn't expect them to this bad. I tried tuning it myself (didn't work) sent it to my local shop for a tune up and with in 2 days it was back to normal. No i don't want to waste my time anymore I want to upgrade to some decent parts sink maybe $250 into the bike and have something thats going to last.

    Another thing I dont understand why downtube don't add to their product line is some sort of guard to stop the bike scratching where it meets on the fold!? Mine is now covered in electrical tape... And another thing why not include a magnet or nice looking strap to hold the fold?

    Don't get me wrong for the money compared to other folders the downtube is a nice bike, I had the chance to get a Birdy White 9 Speed for $750 wish I went with that now.

    Thanks for your replies!

  6. #6
    Senior Member psykoocycle's Avatar
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    GIZ: A lot of people have changed the drivetrains on their DT's...

    If you have already done a tune up and it went back to slipping in 2 days, then it could be the bolt attaching your derailleur hanger to the frame has loosened... tighten it, retune, and if the problem persist or you are still unsatisfied, then proceed with the drivetrain change...

    ESSENTIAL: Derailleur, chain (or adding more chain, depending on the chain ring you mount on), and chain ring.

    IF YOU WANT: Triggers (you can only do 1:1 with the xo, x9, x7... so if you are going with one of these... you definitely need SRAM triggers), if you are going with a shimano derailleur then your twister is fine... changing the cassette (unless you have bent or chipped teeth) won't do much to change things, and is cost prohibitive... the BB if you have =/< FS 2007 may be necessary (I forgot which one had the sealed bearings)...

    try this... for parts...

    www.bestbikebuys.com

    happy modding!

  7. #7
    Wheelsuck Fat Boy's Avatar
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    Here's the cranks.

    http://fmfbmx.com/Merchant2/merchant...ategory_Code=C

    They are square taper cranks, so you can use your present bottom bracket. At $25 they don't break the bank, either. I recommend greasing the BB, though, because it could have come from the factory dry. The bolt pattern lets you use any 'compact' chainrings. I recommend a 50 tooth.

    I used a short cage X.9 derailler and a the X.0 twist shift. Because of the clearance issue, I would only use a short or medium cage derailler, a long cage (like X.5) would be very close to the ground. Like someone else said, if you use a Shimano derailler, you can stick with your shifter, but only if you want to keep it to 8 speeds. If you want to get nine speeds you have to change shifters, chain, and cassette (which is what I figured you were interested in). The good news is that once these parts are dialed in, you can forget about it and you'll have a much more reliable bike.

    I used 'heli-tape' on the frame to keep it from chipping. Electrical tape should work just as well. It should be this way from the factory....a common statement about the Downtube.

    If you have any more questions, let me know.
    Austin doesn't have hippies. They have slightly rebellious Methodists. - Racer Ex

  8. #8
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    Thanks for your help guys, gonna order the SRAM x.7 RD and shifter tomorrow!!!

  9. #9
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    Hey Gilzean,

    its been a while since you posted this thread, but any comments on how the upgrade went? I'm looking to change my shifter, cassette and rear derailer as well, as I have some issues with the gearing, like when i'm in the 9th gear it just doesnt feel smooth, and the skipping from one gear to another.. but also, i got some new handlebars that i want to put on, and the stock juju grip shifts dont fit!! doh!

    so any advice on how it went? which components to get, etc? If you can, can you tell me which exact components to get so they get installed correctly? i'll most likely get it done at my LBS. I just want to know which shifter, cassette, chain and RD will work with the bike as I hate getting this stuff, and finding that I need to change something else for it to work! (like my nice new handlebars that are sitting in a closet for now)

    anybody else got some feedback? fat_boy you seem like a good person to talk to about this stuff. Thanks in advance!

  10. #10
    Senior Member iamstuffed's Avatar
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    Quote Originally Posted by odang11 View Post
    i got some new handlebars that i want to put on, and the stock juju grip shifts dont fit!! doh!
    What do you mean the JuJu shifters didn't fit? What handlebars did you get?

    From the sound of it, it seems you just need to adjust the cable using the barrel adjuster or the limit screws. Also check to make sure the rear derailleur hanger is not bent and if it is, either email Yan for a replacement or bend it straight.

    You should just get the parts that are compatible with each other. If you have a 9spd cassette already, you can just leave it, and buy a shifter and derailleur combo that works (like SRAM shifter, SRAM derailleur, or Shimano shifter, Shimano derailleur). You'll probably have to get new cables.

    You should also just try to install them yourself! It's not that hard, and you can ask all the questions you want here or research online. The components themselves are not that intricate, and if you play around with them enough, you'll figure out what everything does and how they work. If all else fails, you could still take it to a bike shop for the final adjustments of everything. Bike maintenance is much easier after you've replaced components and learned how to adjust everything.

    The shifters and derailleur that come with the bike are crap. Replace them.

  11. #11
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    Quote Originally Posted by iamstuffed View Post
    What do you mean the JuJu shifters didn't fit? What handlebars did you get?
    I got these bars: http://store.somafab.com/sourpubar.html and the matching brake levers.

    I took off the stock handlebar from the stem, pulled the grip off, and loosened the juju grip shift nut and took it off. Then I tried to slide it on the Soma bars, and the diameter of the bar was like 1-2 mm to big. I thought these were all standard and it would fit because the Soma bar is a 25.4mm clamp.. thinking it would allow for the stock parts on the DT to fit. Since i got the new brake levers as well, i didnt see if the stock brakes would fit. So thats why I either need to return the bar, or see if new shifters will work on the bar. And from what I've been reading, getting new shifters/RD is the better option. plus i like my new bars!

    But I guess another important question is, which system should I go with? Shimano/SRAM? the good old debate I guess. I've been reading up on both, and there's no real answer. However, I am worried about people's comments that SRAM's components are a bit wimpier, as in they brake with light-moderate bumps, and being lower to the ground, this would be more of a concern...?

    anybody have any opinions/experience with either? and i'm assuming I have to go with the short cage. and thanks for the advice of doing it myself! I do like tinkering with things, and its good to know that it's not as complicated as it seems (especially with all the help provided here!).

    Thanks again.

  12. #12
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    ahh i see my mistake now!

    "The bar diameter is 23.8mm, like standard road drop bars (and other bullhorn bars), so mountain bike shifters and brake levers do not fit."

    I didn't know that the DT came with this size. I guess I didn't pay enough attention and was focused on getting the 25.4mm clamp size!

  13. #13
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    wow, I wish I read more about the road vs mtb bars before I bought the bull horns!! i can't fit any new shifter setup on these, unless i get an STI or similar component... right?! And i have the brake levers to go with this bar. boo.

    anybody know of a shifter solution to fit onto a 'road' bar (23.8mm), without having to get an integrated shifter/brake system?

    geez i feel stupid now!

  14. #14
    Senior Member snafu21's Avatar
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    Well, since you asked:

    "I am worried about people's comments that SRAM's components are a bit wimpier, as in they brake with light-moderate bumps, and being lower to the ground, this would be more of a concern...?"

    That's 'break', right?

    SRAM v Shimano is the great geek debate. SRAM is favoured by the off-roadies, because the 1:1 cable ration seems to equate to dérailleurs and shifters continuing to operate when full of mud/horse poo/ gravel. The downside is that in the UK at least, SRAM stuff is more expensive.

    SRAM designed only for off-road until a couple of years ago.

    Saying that SRAM's components are wimpier is a vapid generalisation, not a fact. SRAM kit appears on top-end downhill race bikes, and does indeed win races. As does Shimano.

    Shimano finds favour with roadies, and half of the off-roadies, cable pull is 2:1 ratio.

    To throw more grist in your mill, I have a bike with Shimano 105 gears, one with SRAM X7 gears, and a Downtube with Juju gears. None of these bikes give me any cause for concern, although the impulse to fiddle with them to 'improve' them is irresistible. All of them needed a gear cable adjustment twice in the first couple of weeks.

    The JuJu gears are made by Sunrace, and work well for me, shifting issues then, seem to be often caused by cable stretch in the first few weeks of ownership, or a dérailleur or hanger out of adjustment, loose, or bent from new.

    The low dérailleur hanging off the back of a Downtube isn't really a concern for a roadbike, but limits the amount of ruts/mud you'll be able to play in..

    All this rotating stuff wears of course, and whatever you'll fit will need regular lube, maintenance and eventual replacement anyway..

    If you lube and clean regularly, Juju, SRAM and Shimano kit will last for a long time. Jockey wheels are replaceable etc.

    The only danger for tyros is listening to bike equipment snobs who describe this or that as 'crap' with no reference to price or market. A dérailleur or crankset on a $100 mountain bike is not likely to be of the same quality as one on a $2000 roadie, but you'll be surprised at the amount of cross-over in components up and down the range of either Shimano, or SRAM.

    Not everyone maintains their bikes either, then start yelling when something seizes, or when they can't get it back into adjustment.

    Ya pays ya money, and ya might get smoother shifting and longer life. 'Might'.

    My Juju's are fine now they've had a second careful adjustment and a lube, others swap them out a week after they get the bike.

    Here's a little light reading on those old cog-swappers..
    Last edited by snafu21; 07-25-08 at 11:52 AM.
    - every mile of road has two miles of ditch -

  15. #15
    Senior Member JosephLMonti's Avatar
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    Quote Originally Posted by odang11 View Post
    anybody know of a shifter solution to fit onto a 'road' bar (23.8mm), without having to get an integrated shifter/brake system?
    try this:

    http://www.phred.org/~alex/pictures/...swift-bars.jpg

  16. #16
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    thanks for the reply snafu. yeah it is an over generalization that SRAM would be wimpier, I just read a lot of the reviews, however mostly positive about them, but a few had that problem, probably more likely having sustained heavier bumps.

    monti, thanks for the link, and for the one on the DT forum as well! I think i might try to get a different handlebar that doesnt need other addons.

  17. #17
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    for the past few months I've been toying with upgrading the standard JuJu on my NS with an X.9 short cage or X.7 (or X.5) medium cage. Various people have claimed that all their chain-jump and other shifting problems have disappeared. While I'm currently suffering with a missing '4th' gear and inability to use '8' and '9' since the chain jumps off the front chainring at the slightest bump (and yes, I've straightened the hanger and done the barrel adjustment) I'm very hesitant on spending $150+ on the upgrade on a $300 bike. Even though I use the bike virtually daily for an 8 mile commute.

    quick follow up question -- anybody put on a 'medium' cage and did you have to shorten/lengthen the chain?

  18. #18
    Senior Member iamstuffed's Avatar
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    Quote Originally Posted by JugglerDave View Post
    quick follow up question -- anybody put on a 'medium' cage and did you have to shorten/lengthen the chain?
    I used a spare SRAM DualDrive derailleur I had on my girlfriends Downtube and didn't need to shorten the chain. It looks like a medium cage derailleur.

  19. #19
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    I replaced all the drive components on my DT IX one year ago. The stock Juju shifter was skipping gears and shifting poorly. It might actually have been bent in shipping - it was hard to tell clearly.

    At any rate I switched everything to SRAM and have not looked back. Now it shifts like it really should, clean, crisp with no hesitation. I rarely drop the chain. That only happens if I try to shift through too many gears while pedaling under pressure(steep uphills). I ride the bike 5-15 miles daily and it is still as solid as when it was new. IMHO, this is the drivetrain the bike should be sold with.

    I wouldn't hesitate to do this again. I enjoy the bike much more and feel more confident in it now. Basically that translates to me riding and enjoying it more.

  20. #20
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    One thing I haven't seen mentioned on this site is to change to a friction thumb shifter(probably for a good reason). This would make it easier to adjust and wouldn't need it nearly as often. Also, if the cable stretches or the derailleur gets bumped and it needs tweaked, it doesn't have the same type of affect it would if indexed. With friction, a derailleur is just a derailleur. Just food(or junkfood?) for thought. Todd

  21. #21
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    I upgraded to Shimano Deore. See my thread:
    Upgraded (modded) Downtube FS 2007

    The juju gears are OK. Sometimes patient adjustment works and changing the cable tension too. However I have found a significant improvement in shifting with the Shimano Deore plus a trigger shift mechanism. SRAM would also be very similar in this respect. A very worthy upgrade as the Downtube FS frame really is very good and the main parts are a bargain. With an improved gearing set you really then have one very decent bike. I recommend upgrading the pedals to something like MKS in due course. The cranks are someting you could look at in the future but I find mine fine for now.

  22. #22
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    well I bit the bullet & ordered a X.7 medium cage dérailleur and matching twist shifter on ebay. I'll let you know how it goes once the parts arrive & I can get around to installing them some weekend...

  23. #23
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    OK, I put on the X.7 medium cage and twist shifter over the weekend. For the first time doing such a bike install it went quite smoothly, although I wasn't really able to tell if my dérailleur hanger was misaligned or not.

    Today I had my first ride with the new setup. The good news, I can now use the entire 9-gear range. The bad news, I'm still having some skipping in the 6-7 gear range and I also had the chain jump off the front chainring when in 9th gear! So I guess I still have to be careful and/or do some more adjustment to get things right. Or maybe I'll bring it into a shop to do an adjustment once the cable stretches a bit. The shifting action is very nice and precise now.

  24. #24
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    I totally concur with Snafu that the Juju gears are fine on the Downtube FS if cabling is checked and gears are adjusted out of the box. This can sometimes be a little stretched on the FS. However I've upgraded an FS with new MKS pedals, and a Shimano Deore 9 speed with trigger shift. I think you have also chosen some very nice components and this will add to the experience of what is a very good bike. See my thread:
    Upgraded (modded) Downtube FS 2007

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