# Hotrock Upgrades...?



## Dad (Jul 4, 2008)

To all the dads out there...

My son rides a 24" Hotrock and it's time for upgrades. He's getting hydraulic discs and more gears (two front chainrings) - lucky little spud.

Trouble is, I've no idea what goes on kids bikes. I know what I'd like on my bike, but on a kid's?

Please advise/recommend/help.

Thanks


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## bme107 (Jul 23, 2008)

Put anything on your son thinks looks cool or will make him faster. If he has no opinion on a specific item put on a lighter one of them, thus making him faster. Your only limitations are what physically fits the bike and your son. Other than that, have at it.


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## beece (Apr 17, 2006)

I upgraded a 21 speed hotrock. Here's what I ended up with (mostly spare parts floating around the garage):

Xtr hubs, relaced using the same spokes and new alloy nipples to the alex rims it came with.

XT square taper BB, using the same TruVativ Crank it came with, new raceface rings.

Avid Ti levers, XTR V-Brakes.

Sram x9 rear der and shifters.

Truvativ seatpost in red (superlight model - easy to find on ebay for $25)

New tires/tubes. Ritchey WCS flat bars, very short salsa stem.

Judy SL 63mm travel fork for 26" wheel. Still need a new headset, front der, cassette, and brake adapter for the fork.

Total right now is 23.1 pounds. After the last few upgrades I should be about 22.5. Plus, the thing rides great.

So you can go pretty far with the FS-A1 hotrock frame. Good luck.


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## EBasil (Jan 30, 2004)

Our son's A1 FS Hotrock sports a narrowed EC90 bar, Sette Stem, Avid 7 brakes w/combo pads, Sette seatpost, Cane Crk bar ends, skull valve caps and a seat stay mounted reflector (wheel reflectors, too...) instead of the one on the post.

Everything else is so dialed on the bike, and he's hammering it so well, there's no reason for us to change things more before moves up to 26" wheels.


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## lucifer (Sep 27, 2004)

My kids had a 20" hotrock. You can loose a good bit of weight just by swapping the saddle and handlebars for anything decent.


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## EBasil (Jan 30, 2004)

Well I don't know if it will _loosen_ anything... but the oem aluminum bars on the HotRock are a great place to save weight, for sure! I was surprised how heavy that pipe was! The saddle is just so good in terms of size and shape that we chose to stick with it. The seatpost however, is another simple swap that nets serious gram savings.


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## texacajun (Jan 20, 2004)

yep, bar & seatpost are two easy weight savors and they're the same size as adult components. The stem also. Hit up your friends or your own parts bin, or a local swap meet. Like the hydro brakes, these can move up to the next bike and the next...just be careful not to cut them down too far. 

The other quick & easy upgrade that has the best performance bang for the buck is tires. Reducing rotating weight is going to produce the most noticeable results for the kid. Unfortunately these can't move up to the next bike so I bargain shopped hard. And don't forget the tube...those OEM ones are thick & heavy.


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## EBasil (Jan 30, 2004)

Since the HotRock FS has a radial-laced front wheel, you might not want to add the weight of hydro brakes... bad things to follow such a maneuver. You can dial in a nice set of vees to really work well, though. 

The 24" tires are also hard to replace with upgrades from the Specialized rubber, since lighter tires (ie kevlar bead) tend toward $60/tire...just brutal.

Tubes are quick, easy and readily-available, of course. That bottom bracket is a heavy one, too... worth checking your parts bins for old Ti stuff you've become to heavy to enjoy.


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## texacajun (Jan 20, 2004)

Ebasil, I've never really shopped for the 24's (my kid's still on 20") but I saw from their site that Kenda does make the Small Block 8 in a 24". It's a great hardpack/rock tire and it's light.

http://kendausa.com/bicycle/JohnTomac.html#smallblock8

I have no idea who would stock them, but they do exist.


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## EBasil (Jan 30, 2004)

I think that Kenda is a good call, and I bet we can special order them for full-pop from any store that stocks Kenda, I hadn't seen or found that one before! They're 470-550g, wire bead, though. The uber-weight guys in here are talking about the 330g, kevlar bead 1.96 Schwalbe Mow Joes... 64 bucks each. 

Our son's just about through his Spec tires... we'll do them or the Kenda (thanks!) rather than the Schwalbe. Saving 10 ounces off the bike would be nice, but there has to be a limit, eh?


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## texacajun (Jan 20, 2004)

Ouch...the Scwalbe's are pricey. A pair + shipping is almost what I paid for the bike!

You can easily get the kenda's for half that. Tires are the only thing I really bargain shopped. My daughter hasn't been hard on tires so I think they'll make the life of the bike. 95% of our riding is on crushed granite or singletrack.

I've got all the other oem stuff that's going back on the bike when we move up. I got her pink custom end caps and a custom stem cap w/her name as a reward recently so all that is planned to keep moving to each new bike. She insists she wants her stem cap on EVERY bike she has.


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## BunnV (Sep 7, 2005)

beece said:


> I upgraded a 21 speed hotrock. Here's what I ended up with (mostly spare parts floating around the garage):
> 
> Xtr hubs, relaced using the same spokes and new alloy nipples to the alex rims it came with.
> 
> ...


We just got a Hotrock FS-A1 and yours sounds awesome! Please post some detailed pictures!


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## beece (Apr 17, 2006)

Pictures as requested. 

Haven't dealt with the brake adapter for the Judy shock yet, so this is the original RST capa. I yanked one of the springs out and rebuilt it with some lube and oil, and now it's working well for a 65 pound kid. Also, I had Ritchey WCS flat bars on it, but they had been cut narrow and didn't work as well as wider bars, so these are some reasonably light weight no names I had lying around. Will replace with a used carbon riser at some point. Other than that, it's working really well.

Can you tell he likes Bob Marley?


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## xc71 (Dec 24, 2008)

Thats a cool little Hot Rock beece.X2 on the wider carbon riser bar,it makes a huge handling difference for the little guys.I would ditch the big ring for a nice light BBG guard.


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## Cros (Nov 23, 2009)

Dido . Ditch big ring for BBG bash guard. with big ring gone My son now rides over most logs/ rocks etc


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## tamjam (Jan 23, 2004)

I just picked up a used A1 FS 24" HotRock for my son yesterday. I haven't put it on a scale yet, but without any upgrades it already feels lighter than his 20" Kona Makena. Things I plan to upgrade to cut weight/increase performance from my parts bin include:

1) Bar - I have an old Monkeylite riser that's about 25" wide. The stock bar that comes on the bike is about 22-23" IIRC. What's a good width for an 8yr old?
2) Seatpost - I have an EC70 not currently being used. How trick is that? Carbon post on a kid's 24". 
3) BBG bashguard - Ordered and on the way.
4) RD - To choose from I have the long cage XT (M735) from my old Bonty Racelite, a a short cage 105 and a short cage Ultegra. Without the big ring, I think I could get away with one of the short cage ones, no problem. 
5) FD - Found a 31.8 Deore in the bin, and might have an XT that would work too. 
6) Brakes - Are the Tektro v-brakes that come stock on it ok stoppers? I have some old LX v-brakes that I could install, but I am not sure if that is a performance upgrade or not. 

With the above changes, and new cables/housing, I expect this bike will ride really well. Any comments/suggestions about items I am on the fence about are welcome.


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## BunnV (Sep 7, 2005)

*So far, nothing...*

...as far as upgrades go. All we did was take off the front and rear reflectors. I'm just happy that he likes to ride and has been doing bigger and more technical rides each time we go out.

In my opinion the HotRock's weakest part is the fork by far! I think after he has significant time on the bike we'll tune and/or replace the stock fork. Everything else seems to work pretty well but I do agree that a bashguard is a good place to make a change. :thumbsup:


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## beece (Apr 17, 2006)

So, some responses:

Bar width - full bar width might be a little wide, but I tried narrower ones and they don't work as well - radically cut down bars are working well on my daughters 20" bike, but not on the 24" I'd maybe go 24"ish. I don't think 25" is a big problem. My 8 year old is on a 25".

I wouldn't remove the big ring. Weight savings is minimal, and my son uses his big ring all the time. Keep in mind that with 24" wheels the gear inches are lower than on your 26". For example, we rode buffalo creek in Colorado a couple of weeks ago - fairly serious climbs, some somewhat technical downhills - and he spent the whole day in his middle ring.

Watch out for the EC70 - it's a setback post. For little kids you want to compress the cockpit as much as possible, so a non-setback post is considerably better. Also, use a short stem - 80mm tops. On our 20" bike we have a 50mm. Huge difference.

The stock tektro brakes are fine, but the levers aren't very ergo for little hands - though that depends on which year you have.

The shock isn't bad, it's just too firm for a 60-70 pound person. I just removed the spring from one leg, now it moves fine for my 65lb son. Do this at your own risk, but in my experience it hasn't changed the handling - and we hit some very, very techinical stuff on his - stuff that alot of skilled adults will walk. The kids really aren't screamign fast down the downhill, and that high speed is where the lack of compression dampening hurts. At slower speeds, with a much lighter single spring pushing back, the shock is moderately damp anyway. I was very surprised. Though I do have a Judy SL that I will retrofit when he gets bigger, and that will save a pound.

If you do remove the big ring, I'd use one of the short cages you have. It'll help with rock smashing.

Good luck, and have fun!


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## tamjam (Jan 23, 2004)

Thanks for the suggestions. Removing the big ring is not so much about cutting weight, but safety, and the fact that I doubt he'll use it much. The safety concern is after seeing Francis' thread from the other day...

http://forums.mtbr.com/showthread.php?t=641287

I was thinking the same about the EC70. It might be too long for the 11" frame as well, so I might try something different.

The fork is bouncy. Like in a pogo stick kind of way. Rebounds very quickly. Might need to fiddle with it some. Which leg did you remove a spring from? I am hesitant to open it up, with me, things like that have a way of going very badly.

It's a 2007 model, black with red/white accents. I'll leave the brakes alone for now.

Thanks again!


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## dragbike (Jun 10, 2005)

ORiGIN 8 155MM CRANKS, BUT ONLY TAKE ONE CHAIN RING. MY SON DOESN'T NEED A GRANNY RING WITH THE 13-34 REAR FREEWHEEL THAT I FOUND. SINCE ADDED SOME CARBON BARS. I WAS THINKING OF BUILDING UP SOME LIGHT 24" WHEELS BUT ITS BEEN IMPOSSIBLE TO FIND LIGHT 24" RIMS. HE'S A TALL 8YR OLD. I'M ALREADY PLANNING HIS 1ST 26ER SO i DON'T THINK I'M GONNA SINK ANYMORE $$$ INTO THIS ONE.


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## yzblue242 (May 3, 2008)

EBasil said:


> I think that Kenda is a good call, and I bet we can special order them for full-pop from any store that stocks Kenda, I hadn't seen or found that one before! They're 470-550g, wire bead, though. The uber-weight guys in here are talking about the 330g, kevlar bead 1.96 Schwalbe Mow Joes... 64 bucks each.
> 
> Our son's just about through his Spec tires... we'll do them or the Kenda (thanks!) rather than the Schwalbe. Saving 10 ounces off the bike would be nice, but there has to be a limit, eh?


Any comments on the Kenda SBEs? I found a 2010 Forum Raven Rookie that I'm going to pick up for my 8 year old this week and am planning on swapping out the stock tires for the SBEs.


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## TigWorld (Feb 8, 2010)

EBasil said:


> ...The uber-weight guys in here are talking about the 330g, kevlar bead 1.96 Schwalbe Mow Joes... 64 bucks each...


The two Moe Joes in 24" kevlar bead that I got weighed 407g and 425g. Claimed weight on the box is 420g. The 330g weight is for the 20" versions.


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## 4mula1 (Oct 31, 2008)

I bought Small Block 8's for my daughter (20"). Well, Santa did. "Santa" was on a budget so they are the wire bead but they've been really good for her. I was able to get one at the LBS and the other came from Amazon.


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## IAmHolland (Jul 8, 2010)

dragbike said:


> ORGIN 8 155MM CRANKS, BUT ONLY TAKE ONE CHAIN RING. hE DOESN'T NEED A GRANNY RING WITH THE 13-34 REAR FREEWHEEL THAT I FOUND. SINCE ADDED SOME CARBON BARS. I WAS THINKING OF BUILDING UP SOME LIGHT 24" WHEELS BUT ITS BEEN IMPOSSIBLE TO FIND LIGHT 24" RIMS. HE'S A TALL 8YR OLD. I'M ALREADY PLANNING HIS 1ST 26ER SO i DON'T THINK I'M GONNA SINK ANYMORE $$$ INTO THIS ONE.


What frame is this? s-works? it doesn't look like a hotrock.

@Dad, I don't believe the Hotrock 24" frame is disc ready.


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## dragbike (Jun 10, 2005)

IAmHolland said:


> What frame is this? s-works? it doesn't look like a hotrock.
> 
> @Dad, I don't believe the Hotrock 24" frame is disc ready.


It's a previous gen Hotrock. Like 2006 ish I think. Bought the bike off craigslist for $100, like new practically but frame was yellow.. Stripped the frame and my son chose gold for his color choice. Used rustoleum gold plus a clearcoat. Found the stickers on ebay. turned out real nice.


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## IAmHolland (Jul 8, 2010)

dragbike said:


> It's a previous gen Hotrock. Like 2006 ish I think. Bought the bike off craigslist for $100, like new practically but frame was yellow.. Stripped the frame and my son chose gold for his color choice. Used rustoleum gold plus a clearcoat. Found the stickers on ebay. turned out real nice.


nice work! it looks awesome, and must have been some hard work to strip it down.


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## tamjam (Jan 23, 2004)

IAmHolland said:


> I don't believe the Hotrock 24" frame is disc ready.


The 2007 Hotrock A1 FS 24 I just picked up for my son does have disc tabs on the fork and frame.


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## IAmHolland (Jul 8, 2010)

tamjam said:


> The 2007 Hotrock A1 FS 24 I just picked up for my son does have disc tabs on the fork and frame.


i stand corrected. i just took a look, and sure enough you're right.


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## tamjam (Jan 23, 2004)

So far I have swapped out the stock flat bar for an Easton Monkeylite aluminum bar, installed new twist shifters (the gear indicator windows were cracked/missing on the original ones) with new cables/housing, swapped out the stock RD for a spare Ultegra, put on the BBG guard in place of the big ring, and installed a new/shorter chain. That cut the weight from 28.1lbs in stock condition down to 26.4lbs. Only thing left on the immediate agenda is getting back an old no-name carbon fiber seatpost that I loaned to a friend a long time ago. That should put it under 26lbs for a total cost of ~$30. 

I'll add a pic to this thread once I am done.


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## mmmm (Aug 14, 2006)

Four years ago bought a Specialized HR 24" for my daughter. My goal was to make it a little lighter and more fun to use. Main problems were:

Shifters were hard to use (revo)
Brakes were ok at best with lousy reach on the levers (tektro)
Gearing worked barely (7 speed shimano system)
tires were lousy (specialized baldy)

Final rendition of the bike is as follows


Easton Monkey lite sl handle bars cut to fit
cane creek headset
shimano xt front and rear hubs -8 speed
dt comp spokes and brass nipples
 kept the alex rims
shimano xt rear mech
magura hs 33 rim brakes
raceface ti tapered BB
race north shore 160mm cranks
race face 8 speed rings
xtr rear cassette
sram pc 68 8 speed chain
deore shifters
tioga comp III front
maxxis holy roller rear
generic 80mm stem
stock seat
stock seat post
stock front derailliuer
stock front fork
dangerboy pedals

lost roughly 4 lbs off the bike. Biggest savings was the crank and bb. Remember to keep the crank short as a longer crank will affect the turning and lean of the bike. No fun jamming a pedal into the dirt. 
Most of the parts were from the spare parts bin in the garage. 
Magura HS 33 rim brakes are great for kids bikes. the levers can be moved close to the hadle bars for there much smaller hands. Great power and easy to adjust.


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## BunnV (Sep 7, 2005)

I want to keep this thread alive...

This is not mine but I found a picture of a HotRock with disc brakes installed for those that are considering this mod...

source:http://www.singletrackworld.com/forum/topic/help-needed-re-fitting-discs-to-my-sons-hotrock


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## rockymtnrider (Apr 29, 2007)

tamjam said:


> The 2007 Hotrock A1 FS 24 I just picked up for my son does have disc tabs on the fork and frame.


How does the full suspension work? does it bog and rob power? Trying to figure if I should buy a FS or hardtail for my son. What is the weight of the bike stock? If you know.
Thanks.


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## BunnV (Sep 7, 2005)

rockymtnrider said:


> .... What is the weight of the bike stock? If you know.
> Thanks.


Our 2010 is a hardtail and currently weighs 26.41lbs. It's completely stock with the exception of removing the front and rear reflectors and the wheel reflectors.


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## BunnV (Sep 7, 2005)

*"New" wheels!*

Ok! We've finally started our upgrades! &#8230;.Custom hubs and spokes, an 8 speed SRAM cassette, and Crank Brothers "Smarty" pedals. The pedals were taken off my Mojo. All in all, we lost .75lbs and added an 8th gear (not usable yet with the stock 7 speed shifter).

I found some Novatec hubs on eBay for $79. The front hub and the skewers are 50 grams (total) lighter than the original parts. The new rear hub is actually a little heavier than the stock hub but the stock freewheel weighs over 500 grams! We replaced it with a SRAM PG-850 cassette from Price Point ($32) and saved 242 grams (including the weight of the dork disk).

We used black spokes and nipples with the original Alex rims for a custom look. I paid $110 labor to lace the hubs and spokes to the stock rims. I'm not happy with the red color of the hubs. It doesn't go as well with the red frame as I had hoped, and the skewers actually look pink. :madman: We're going to change the skewers to black later.

Total current weight is 25.66 lbs. Comments and criticisms welcome.


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## wycough (Mar 9, 2008)

Whatg size BB bracket did you guys use for a replacement on the 1x7 Hotrock?


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## mmmm (Aug 14, 2006)

68 x 113 BB shell. For 2003-2005.


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## wycough (Mar 9, 2008)

I think our new one is a 2007. The newer style frame 24"


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## mmmm (Aug 14, 2006)

68x128 for both boys and girls 1x7 frames 24"


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## wycough (Mar 9, 2008)

68 x 128 doesn't seem to be all that common. Especially in Ti square taper.


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## TigWorld (Feb 8, 2010)

128mm wide seems large for a kids bike. Are there crank arm / seat stay clearance issues on the frame?

I'd measure the chainline and decide on what bottom bracket width you can get away with from there. If you're not running a triple front you can probably get away with a 68 x 118 or even 113.


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## mmmm (Aug 14, 2006)

Specialized 2007 hotrock boys 1x7



> BOTTOM BRACKETVP, watersealed loose ball, square taper, 68 x 128mm


The 2007 3x7 takes a normal 68x113. My guess is it has to to with the crankset used.

specialized link


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## Jeffnrivercity (Aug 26, 2009)

Just replaced my sons BB with a Sinz BB..it was a 68x113


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## steve447 (Mar 18, 2009)

*RST Capa spring removal*

Just bought a barely used, never seen dirt 2004 HotRock FS for my 7 year old and need to soften the front spring on the RST Capa T4 fork. Can anyone confirm those plastic rebound knobs just push on? I am reluctant to lever on them too much in case there is a special technique

Thanks


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## BunnV (Sep 7, 2005)

Jeffnrivercity said:


> Just replaced my sons BB with a Sinz BB..it was a 68x113


That's a nice weight savings! Is that the Ti "Pro" version?


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## TigWorld (Feb 8, 2010)

Jeffnrivercity said:


> Just replaced my sons BB with a Sinz BB..it was a 68x113


Very nice.


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## Jeffnrivercity (Aug 26, 2009)

BunnV said:


> That's a nice weight savings! Is that the Ti "Pro" version?


Yes it is the Ti Pro version...
Trying to lighten his FSR up a bit..


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