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  1. #1
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    Specialized Hotrock 24

    I'm still in the process of building it up, but here it is so far. This is my sons Hotrock 24. The goal is to drop some wieight off of the bike initially and eventually I will convert it to 1X8 or 1X9 with a new rear wheel build. Mods so far:

    Replaced heavy stock steel bar with an alloy bar from the parts box
    Removed chain tensioner, stock bottom bracket and crankset
    Added a set of AC Mini LE cranks I got off Ebay with a 36T RaceFace sprocket and an Origin8 bottom bracket. Added a set of alloy mini platform pedals.
    Those mods shaved about 1 1/2 pounds. I will probably need a chain guide.

    I am looking to order a set of Small Block 8's and maybe throw on a 'MegaRange' cassette since my LBS has a new takeoff for $15. That may help delay the need for the 8 or 9 speed upgrade for awhile.
    Attached Thumbnails Attached Thumbnails Specialized Hotrock 24-img-20120819-00032.jpg  


  2. #2
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    What's the weight on the SB 8's? For 24" I've found the Schwable Moe Joes (420g) or the Schwalbe Rocket Ron (445g) to be the top choices for offroad. Loads of grip, fast rolling, lightweight, work well ghetto tubeless. Only drawback is they are expensive.

  3. #3
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    Quote Originally Posted by TigWorld View Post
    What's the weight on the SB 8's? For 24" I've found the Schwable Moe Joes (420g) or the Schwalbe Rocket Ron (445g) to be the top choices for offroad. Loads of grip, fast rolling, lightweight, work well ghetto tubeless. Only drawback is they are expensive.
    The SB8's are supposed to be around 550G or so. I think the stock Specialized Rollers are around 700G+. I've looked at the Moe Joes, but I want something wider. I'll check into the Rocket Rons.


    I'm bummed I just missed out on a 2001 Specialized Rockhopper Pro for $40 on CL this weekend. I would have used the XT rear derailleur, LX rear shifter, 9 spd 11-32 cassette and had the wheels re-laced for the Hotrock. I could have sold the frame and fork and come out ahead.

  4. #4
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    pcmark,
    Going through something similar that I posted yesterday. The seatpost is another area that you can really lose some weight. Luckily, I had an spare carbon fiber one laying around.

    I second the Rocket Rons - great mountain bike tire and light weight. Only problem is the price.

    I've heard the bottom bracket is heavy and the cranks and chain tensioner look beefy as well. I may consider going to a 34 tooth front chainring to make it a little easier to climb.

  5. #5
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    Quote Originally Posted by CrashCanipe View Post
    pcmark,
    Going through something similar that I posted yesterday. The seatpost is another area that you can really lose some weight. Luckily, I had an spare carbon fiber one laying around.

    I second the Rocket Rons - great mountain bike tire and light weight. Only problem is the price.

    I've heard the bottom bracket is heavy and the cranks and chain tensioner look beefy as well. I may consider going to a 34 tooth front chainring to make it a little easier to climb.
    Stock BB is a tank and is open bearing. The tensioner is about 3/4 lb alone.

  6. #6
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    Weight vs durability vs price...an issue with all kids' bikes. After years of trying to modify (lighten) my own kids' bikes, I just gave up and accepted the situation. Plus, they'll outgrow the frame in a mere 6 months. Thus, the person actually benefiting from your effort is the NEXT owner! ;-)

  7. #7
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    Ended up ordering some Small Block 8's. I found some for $24 each so I figured that'll do for now. I found an IRD 13-32 7 speec freewheel on Ebay. Keping an eye on the bids.

  8. #8
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    chain guide?

    you mentioned you may need a chain guide/...are you seeing problems? or guessing problems when going to 1x9....Im in process of a 20" Hotrock build and was thinking of removing the chain guide...

  9. #9
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    Just picked up an older model hotrock 24 for my nephew and changed the bars to a flat bar because he is a little small for it at 7 it it brings to reach in and saves weight. I figure he can go to risers when he's on the top of the age range at 10-11. The bottom bracket on his was wobbly and I had a new sealed shimano unit on the shelf that installed good. I used the stock cranks and noticed the chain tensioner used the old BB to mount to so that went in the parts bin. Seems ok, chain is a little close to the rear tire but seems to work good. Also changed out his brakes with some avid / cane creek v-brakes I had which makes it stop better than the stock units. Made sure to cinch up the bolt to make the lever move closer to the bar for smaller hands, but they worked good. The rest is a 1x7 speed grip shift setup that seems simple for him to use because sometimes a front deraileur is confusing for the novice. New pedals, cables, BB, flat bars and it's ready to go. He'll be stoked for his B-day coming up.

  10. #10
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    Quote Originally Posted by sledz View Post
    you mentioned you may need a chain guide/...are you seeing problems? or guessing problems when going to 1x9....Im in process of a 20" Hotrock build and was thinking of removing the chain guide...
    Mostly anticipating the chain jumping off occasionally. No problems yet, but only short test rides so far.

    I picked up a 13-32 7 speed freewheel off of Ebay. It should be here in a few days. This is way better than the Mega-Range cassette, because it's wider ratio all-around and not just a 10 tooth jump on the end. The range is:

    13 15 17 21 24 28 32

    I know an 8 or 9 speed cassette would make more sense, but I can't justify the additional cost for a wheel build, shifter, and derailleur at this point just to get another one or two gears when I can get more usable gears now. I think i'll also get a 34 tooth chainring for the front. A 34-32 low gear isn't great, but we're not going to be doing any big climbs for awhile.

  11. #11
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    cassette range

    great...I'm in process on a 20" build... i have a old 11-34 9speed SRAM 990 casette and X9 derailer..I made the jump on a rear wheel build...expensive !! even though I had a hub and cassette!! $50 wheel build, $32 for spokes, $10 for RED alloy nipples and a new rim at $26
    out of the shop for $120....but Im in Colorado and the range helps on all the different terrain

  12. #12
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    Specialized Hotrock 24, Specialized Hardrock 20, Schwinn Chameleon 12

    Here's the Specialized Hotrock 24 that I changed the bottom bracket, bars, pedals and brakes on. Also picked up Specialized Hardrock 20 if the 24 is too big by my 7 y/o nephew. Also a cool Schwinn Chameleon 12 for my niece who's getting ready to go off training wheels. Good size to put her legs down, not too tall and it has a removable crossbar for double duty. Seems like cool bikes abd I like the little hard rock 20 from the 90s with the dia comp brakes + my suntour xc stem and ritchey race light bars. Too cool for school.
    Attached Thumbnails Attached Thumbnails Specialized Hotrock 24-specialized_hotrock_24.jpg  

    Specialized Hotrock 24-schwinn_chameleon.jpg  

    Specialized Hotrock 24-specialized_hardrock_20.jpg  


  13. #13
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    My son has a hot rock 20 and he droped the chain tonight on our ride. The stock chain keeper was bent just enough to let it out. I think I'm goin to scrap it and buy a cheap seat post mount type. Other than that its a great bike! I am looking at 24's for him now but think I might just wait until he can fit a XS 26er. His bike handling skills have really come a long way this summer! Here is a pic from tonights ride it was his bday today! 9yrs old!! I'm 6'1" I think he is almost 5'.

  14. #14
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    I got the new freewheel on there and its great except that the derailleur cage hits the 28 tooth cog when I'm up on the 32 tooth. The Tourney doesn't appear to have any type of B tension adjustment to try to move the cage down a bit. The newer model Tourney's have some 'smart cage' design that supposedly solves this problem. I hate the idea of buying another 7 spd derailleur but I can grab one for under $20. I also got my Small Block 8's but no pics of those yet,
    Attached Thumbnails Attached Thumbnails Specialized Hotrock 24-img-20120903-00034.jpg  


  15. #15
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    Quote Originally Posted by pcmark View Post
    I got the new freewheel on there and its great except that the derailleur cage hits the 28 tooth cog when I'm up on the 32 tooth. The Tourney doesn't appear to have any type of B tension adjustment to try to move the cage down a bit. The newer model Tourney's have some 'smart cage' design that supposedly solves this problem. I hate the idea of buying another 7 spd derailleur but I can grab one for under $20. I also got my Small Block 8's but no pics of those yet,
    Maybe shorten the chain?
    Work to Ride - Ride to Work
    There's no such thing as bad weather, just bad clothing...

  16. #16
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    Quote Originally Posted by Asmodeus2112 View Post
    Maybe shorten the chain?
    I suppose I could try that. I'll grab a picture for you guys first and maybe you could tell me if you think the angle looks OK. If I take out a link or two the cage will be nearly horizontal in the low gear.

  17. #17
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    Quote Originally Posted by brushman View Post
    Weight vs durability vs price...an issue with all kids' bikes. After years of trying to modify (lighten) my own kids' bikes, I just gave up and accepted the situation. Plus, they'll outgrow the frame in a mere 6 months. Thus, the person actually benefiting from your effort is the NEXT owner! ;-)


    Couldn't you always revert it back to stock to sell it???

    Keep the aftermarket parts for later or part them out?

    Seems like a win-win, unless you are selfish and only like spending money
    on your own bike! j/k

  18. #18
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    I put an older XT Derailleur on the one I had and it shifted fine. Had a few things in the parts bin for it like the derailleur which helped. The R Der and the Bottom Bracket and the brakes were the weakest links on the stock bike. Don't think it has to be a 7-speed, maybe an older STX or LX would work too.

  19. #19
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    I ended up ordering a newer model Tourney rear derailleur off of Ebay. It should be here in a few days. I think it will work. The upper pulley is larger, which will push the cage away from the sprocket. It also has a B tension adjustment, which the current one lacks. That should solve the problem. After that, I'll be done with the bike for awile,

  20. #20
    turtles make me hot
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    I just built my son a 24" GF Tyro very similar to your Hotrock.
    I ended up with a 1x10 X7 drivetrain with a Shimano cassette. Didn't cost any more than the 9 speed stuff. I used a Sinz Crankset, Salsa 34 tooth chainring, Salsa Tooth Fairy chainguard and an N-Gear Jumpstop on the inside. He hasn't dropped a chain yet.
    I like turtles

  21. #21
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    Quote Originally Posted by NYrr496 View Post
    I just built my son a 24" GF Tyro very similar to your Hotrock.
    I ended up with a 1x10 X7 drivetrain with a Shimano cassette. Didn't cost any more than the 9 speed stuff. I used a Sinz Crankset, Salsa 34 tooth chainring, Salsa Tooth Fairy chainguard and an N-Gear Jumpstop on the inside. He hasn't dropped a chain yet.
    Sounds awesome. Lets see some pics. I'd like to se the Jumpstop too.

  22. #22
    turtles make me hot
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    I'll try. I've been on here for a few years and I've never had success posting pics.
    I like turtles

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