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Thread: Diet Rush Build

  1. #1
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    Diet Rush Build

    I picked up this XL 2008 Rush 4 SL on eBay. I was looking for a Caffeine frame, as I live in Flat Ohio, but when I ran across this it was just too pretty to pass up for the price.

    Diet Rush Build-0152e89e6f7e0c0f1f45557b0467f8423fb4613d79.jpg

    "Before" Specs
    • XO 3x9 Twisties
    • Deore FD
    • LX 3x Crankset
    • X5 9x Long RD
    • Juicy 7 Brakes
    • Lefty Speed
    • Fox Float RP23
    • Mavic CrossMax SL Wheelset
    • Maxxis Ardent 26x2.25 Tubeless Tires
    • Cannondale Competition Alloy Seatpost
    • Easton EA30 Alloy Handlebars



    Surprisingly for an eBay bike, everything works flawlessly- so I've decided fix that by seeing how light I can get it, without spending more than I paid for the bike.

    I also wanted to go single chainring. A new SRAM GX 11-speed group would have fit the bill, but the rear hub on the Mavic wouldn't handle an 11 or 12-speed (without a $100 adapter that no one seems to carry), and piecing together a 10-speed was more expensive than the 11 speed kit. So I decided to go with a SunRace 11-40 9-speed cassette that would let me slowly upgrade the rest of my existing drivetrain as needed or as parts were found cheap. ...And then I promptly bought replacements for everything but the XO twist-shift over the course of a week- including a BB30 XO crank, which was super cheap and light, but which probably has the fewest bottom bracket options for a BSA 68 threaded frame possible. Research is your friend.

    Planned Changes
    • XO 1x9 Twisty (stock)
    • XO BB30 Carbon Crank (used)
    • Shady no-name BSA30 BB from eBay
    • Absolute Black 34t Oval Direct Mount Single Ring
    • SunRace 11-40 Cassette
    • x0 9x Short RD (used)
    • SRAM PC-1071 Hollow Pin 10 Speed Chain (Absolute Black ring requires a 10-speed chain on 9-speed setups)
    • Easton Carbon Monkey Bars (used)
    • Enough Titanium bolts to build a fighter jet, because RAINBOWZDiet Rush Build-0151e98a9896174b407203d54cdd54475613716c1e.jpg


    I'm still waiting on the XO rear mech and for some of the Ti bolts to arrive from the Mysterious Orient, and I still need to figure out the bolt sizes for the Juicy caliper clamshells and lever reservoirs, but the bottom bracket finally arrived by slow boat yesterday, so now it's time to get started. I'll post weights and bolt sizes as I go.

    Diet Rush Build-012c07845c29360866ba62c80dfccc285fafba8e8e.jpg

  2. #2
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    Love the old Rush! Definitely consider the 650b/27.5 wheel conversion, really works quite well on the Rush and can be done without adding weight. See the 650b Rush posts on these forums.

    You should be able to get that XL alloy bike to 26lbs or less without much effort. I still enjoy riding a 2009 Carbon Rush, 24.5lbs with a 2.6 Nobby Nic on the front!

  3. #3
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    Hope

    Thanks! Yes, I would like to go 27.5 eventually.

    Made a little more progress last night. Can't get over how much lighter the XO mech is than an X7 I had laying around- should be waaaay lighter than the X5 on the Rush now. Next step is to sneak the wife's bathroom scale out to the garage for a Before weigh-in, and then I start the overhaul...

    Diet Rush Build-0127713127ee532c5208a02af300fb884a894a70ac.jpg

    Diet Rush Build-0124f34f4c88c3139beb647b4fbf2f83e285012c24.jpg

  4. #4
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    To get ready for the build, I did a weigh-in by taking my weight on the digital bathroom scale, then taking it again while holding the bike. Tried it 4 times and triple-checked my math because I didn't believe the results, and got the exact same weight every time - 26.0 lbs, dirty and with the Mallets on. Can it really be that light already? I figure the drive-train upgrade will shed at least a pound.

  5. #5
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    Looking forward to an update on your build. I still ride an '07 Rush.

  6. #6
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    Good news: Got everything swapped out and dropped 1.5 lbs on the drivetrain alone!

    Bad news:
    Accidentally broke the chain too short because I was moving it between the big and middle ring to check length and chainline,
    and then cut it with it in the middle ring. Popped an extra master link in and fixed that.

    Then I was trying to clamp my stem to the fork with a 15mm Ti bolt when it needed a 20, and managed to strip the threads out of the stem.
    Fortunately I have 3 or 4 spare stems- though not the angle/length combo of the one I wrecked.

    I also seem to have misplaced the m4x25 Ti bolt I bought to make the rear mech reach the 40t ring.

    Anyhow, everything is looking good- but the chain won't stay on the Absolute Black oval ring. Chainline is good - hops off inboard if I put it in the top gears, and outboard for the wee ones. Still jumps if I put it in the middle gears. It definitely has something to do with the oval, as I can see it go from fine to shifting off based on the spot in the pedal stroke. I have not yet stripped the packing grease off the chain and properly lubed it, since I have been building this in my office. Hopefully once I do that things will work smoother and it will stay on.
    Diet Rush Build-019450a2caf5d265dcd580d0ebfc968d2e4431b68c.jpgDiet Rush Build-01cd01a4f31eb33bdd1187d0341f1537a539375850.jpgDiet Rush Build-0184d0b654c701ee9aca868cb408e743aeb1556eca.jpgDiet Rush Build-01bfe24c4aa9f7c85336bb12af38dba8b1d818724e.jpgDiet Rush Build-01bdf3af4e8372cd98c352b2e62481c0aa582267aa.jpg
    Last edited by Josh_W; 06-21-2017 at 08:44 AM.

  7. #7
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    Also: holly cow - if you are selling a bike, why would you not at least rinse off the sand before you box it up?

  8. #8
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    Gave the bike a bath last night and lubed the chain. That definitely helped, and I think the front ring will be fine once I get the derailleur adjusted.

    The stem I put on looks goofy and makes my shift cable too short, but it sure is comfy. I'm going to either helicoil the other stem or re-tap it up to m7. Decided to order a fresh Jagwire Mountain Elite Sealed shift cable kit anyhow.

    So now I'm waiting on an m4x30 Ti derailleur adjustment bolt and the shift cable. I need to pick up the tools to repair the stem. I also need to pick up an m6 nut or two to use when I Dremmel down the m6x15 Ti mushroom bolts to 8mm for the Fox pivot mounts.

    I decided not to pick up Ti upgrades for the Juicy caliper and lever assembly bolts (I already did the mounting bolts) because I may swap the whole lot out for Ultimates or Elixirs (or ....?) at some point.

    And I will probably break down and get Ti spindles for the Mallets - if I don't just swap them for the Ti Candies I have on my F-Whatever.


    Diet Rush Build-01fbc4c2f0ce455348d2201033e7c14b45c79c575c.jpgDiet Rush Build-0197af8003b5fac2ec0c91529fb1ee2a2a1aee5c7a.jpg
    Last edited by Josh_W; 06-22-2017 at 01:39 PM.

  9. #9
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    Bonking ... not feelin' well

    The titanium 30mm B screw came in Friday, but the rear mech still won't clear the 40t cog. Hopefully someone in the drivetrain section can help...

  10. #10
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    Re-tapped the 100mm/20* stem to 7mm last night and installed it. Used a plain silver Ti bolt because I couldn't bring myself to spend $15 for one rainbow bolt.

    Replacing the 110mm/30* stem made my old shift cable fit, but I already ordered in a new Jagwire Mountain Elite Sealed kit that I'll be using once I get the rear derailleur fitted properly. Speaking of which, an Absolute Black RoadLink should arrive today and will hopefully resolve the derailleur clearance issue.

  11. #11
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    The RoadLink is magic - I ended up putting the stock B screw back in, and it still has room for adjustment. Finished up the shift cable install and derailleur tuning today and took it for a spin around the driveway.

    There is a little bit of clatter from the derailleur in the 40t, and the chain sometimes jumps off when on the stand, but not under load. A clutched derailleur might help, but the real issue is chainline. Not much I can do about that unless I want to get an offset GXP crank ring. For the couple times a year I expect to need the 40t, I'll live with the clatter.

    There is also some drag from the new pads on the rear Juicy. The pistons are all the way in, but I think the Clark pads I put on are just that thick. I've been assembling bikes for 30 years but am a total n00b with disc brakes, so if it doesn't wear in I'll take it to a shop.

    There may also be an issue with the eBay BSA30 bottom bracket. The bearings don't feel perfectly smooth to me, and when I torque the crank arms on it feels like it adds some drag- but it's hard to tell with the brake already dragging and the chain clattering. If it starts creaking I'll either drop real money on a brand name BSA30 BB or sell the XO crankset and pick up something with a more common BB, like Hollowtech II.

    Aside from working out the bugs, the only thing I have left to do is cut down four Ti bolts for the Fox pivots. Once I have those done I'll take some more pictures and put together a list of all the bolt sizes on the Rush in case anyone else wants to replace their bolts.

  12. #12
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    I'd like to try something like this on my Rush for the shock mounts. From what Ive found, they are 32,5 and 37.5 mm long.

    1 Shock Axle 32 mm + 2 Screws all in Titanium - 43% lighter - 4 colors on choice

  13. #13
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    Nice find! I couldn't find the axles in Ti, so I just picked up some mushroom-head bolts. I still need to bust out the Dremmel tool to cut those down.

    Rode the thing around my back yard, which is on a steep hill, yesterday, and I can tell the 34x40 gear combo will be fine for Central Ohio. Everything was working smooth, but I didn't really take the time to get a feel for how the BB is doing.

    I picked up a huffed set of Crank Bros. Candy 4Ti pedals on eBay super-cheap, and attempted to migrate the Ti bits into my like-new Candy Cs, but I'm not sure it's going to work out - as in I may have bricked both sets of pedals. Plan B is to see if I can use the Ti wings on my Mallets, and then pick up some Ti spindles for those.

    Once I get the last of the Ti bolts on and get the pedals sorted I'll do a final weigh-in.

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