# Hotrock Replacement parts size?



## panamamike (Sep 11, 2008)

Wanting to know how I determine the right size for replacement parts.
For example. The bike has 20x2.125 tires can I replace those with a different size
say 20x 1.95 or 20x2.1 on the same rim?

As far as grips, I saw a recommendation for ODI grips. I can't seem to determine which are the correct grips. I saw a 90mm that looks to fit the short grip, but how about circumference of the bar. Is that standard from adult to kid sizes?

Any help is much appreciated.

Regards,

Mike


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## indianadave (Apr 27, 2010)

The tire should work fine.
The grips should be the same as adult bikes.
Get the thinnest grips you can find. I bought some Ritcheys and they are too fat for my little girls hands.


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## TwoTone (Jul 5, 2011)

panamamike said:


> Wanting to know how I determine the right size for replacement parts.
> For example. The bike has 20x2.125 tires can I replace those with a different size
> say 20x 1.95 or 20x2.1 on the same rim?
> 
> ...


My son is on the smaller size and did not like the ODIs I put on for him, to large of a diameter. He liked standard lizard skins that came on my Tallboy a lot more.


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## panamamike (Sep 11, 2008)

Does anyone know the proper stem size of the hotrock? I saw one mention it's 25.4
The info. I've read on the web says threadless 1 1/8 those are supposed to normally take a 31.8 handlebar, but I read on another site that the bar is 25.4 mm. 

From my rough measurements I see the handlebar looks to measure 25.4 mm in diameter, but I want to be sure.

Is that correct for all hotrock 20 inch mtbks? I'm asking since I have a 2008.

Also, can the existing stem accept a carbon fiber handlebar or would I also need to replace the stem?

Regards,

Mike


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## pcmark (Jul 10, 2010)

The stems take a 25.4 bar, and you can put a carbon fiber bar on there assuming it's 25.4 as well.


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## Surfpoodi (Sep 14, 2011)

The steer tube on an 08 HR is 1 1/8. The bars are 25.4. The stock stem and bars are quite heavy, so I swapped out the stem for a mini 30mm and put some old carbon fiber bars on. Dropped a lot of weight there, and helped the sizing for my 4 year old.


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## panamamike (Sep 11, 2008)

Surfpoodi said:


> The steer tube on an 08 HR is 1 1/8. The bars are 25.4. The stock stem and bars are quite heavy, so I swapped out the stem for a mini 30mm and put some old carbon fiber bars on. Dropped a lot of weight there, and helped the sizing for my 4 year old.


Thanks for the info., funny thing is your answers end up resulting in more questions  If the steer tube is 1 1/8 and I decided on getting a new handlebar and stem. Would it make more sense to get a 31.8 stem and handlebar or do I need to stick to the 25.4 due to the steer tube and bike design?

Also, I was thinking I'd just get something similar as far as specs. to what's on the bike, 20 degree 90mm stem. However, I'm not having much luck with finding such a stem. I also wasn't able to find that mini 30mm, at least not in stock and it looks quite a bit different from the stock stem. How will I know if the fit will be right?

That's a bit of a different topic. I did get an idea of the frame size, tube length and height of the bike. However, I'm not sure how you determine the proper lean over the handles.

Any help would be much appreciated.

Mike


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## marmoset (May 1, 2007)

I'd stick with a 25.4mm bar & stem combo, not because the 31.8 won't fit but because the o/s bars might have a wider bulge than the standard 25.4 and if you're cutting down to width it will restrict the distance the controls can move inboard. I'd also imagine that 25.4mm is cheaper as well.


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## panamamike (Sep 11, 2008)

marmoset said:


> I'd stick with a 25.4mm bar & stem combo, not because the 31.8 won't fit but because the o/s bars might have a wider bulge than the standard 25.4 and if you're cutting down to width it will restrict the distance the controls can move inboard. I'd also imagine that 25.4mm is cheaper as well.


Cool, that sounds reasonable. On the topic of cutting down, I've read that some handlebars are designed to be reinforced in certain areas to deal with compression, I'm assuming this is for gripping the breaks ect... Is this a real issue or should it be o.k. with some end plugs?

I'm currently looking at second hand Easton monkey light bars...

I'm also wondering if it matter that I get a straight vs. rise style handlebar. From what I've read, it seems the rise style bars are easier to control and more comfortable? Straight bars are for speed and hard climbs?

Regards,

Mike


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## veelz (Jan 12, 2004)

panamamike said:


> Cool, that sounds reasonable. On the topic of cutting down, I've read that some handlebars are designed to be reinforced in certain areas to deal with compression, I'm assuming this is for gripping the breaks ect... Is this a real issue or should it be o.k. with some end plugs?
> 
> I'm currently looking at second hand Easton monkey light bars...
> 
> I'm also wondering if it matter that I get a straight vs. rise style handlebar. From what I've read, it seems the rise style bars are easier to control and more comfortable? Straight bars are for speed and hard climbs?


You're right that some carbon bars have reinforced areas for clamping, and therefore have restrictions on how far down they can be cut. Remember though, it is designed for a full size adult male. Clamps on brakes, shifters, and grips should only be tight enough not to slip, that threshold is generally lower for a kid. By the time we cut down bars, the material doesn't matter that much in weight, so long as it isn't steel. Riser bars vs. straight is a personal choice. You can use higher rise stems to move the controls higher, but with super short stems, not going to affect much (a reason not to cut down steerer tubes). Riser bars will limit the amount of space you have for controls too, and then you can't cut them down. For super short stems, BMX ones might work, and they usually have a drop that can be flipped over for rise, so long as you have the right steerer tube length. Getting your kid out there is the most important thing, heavy bike or not; make it fun.


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## panamamike (Sep 11, 2008)

veelz said:


> You're right that some carbon bars have reinforced areas for clamping, and therefore have restrictions on how far down they can be cut. Remember though, it is designed for a full size adult male. Clamps on brakes, shifters, and grips should only be tight enough not to slip, that threshold is generally lower for a kid. By the time we cut down bars, the material doesn't matter that much in weight, so long as it isn't steel. Riser bars vs. straight is a personal choice. You can use higher rise stems to move the controls higher, but with super short stems, not going to affect much (a reason not to cut down steerer tubes). Riser bars will limit the amount of space you have for controls too, and then you can't cut them down.


I plan on getting one of the shorter bars, 610 mm, hopefully taking an inch off will be o.k.



veelz said:


> For super short stems, BMX ones might work, and they usually have a drop that can be flipped over for rise, so long as you have the right steerer tube length.


Plan on using stock stem.



veelz said:


> Getting your kid out there is the most important thing, heavy bike or not; make it fun.


I agree, we've actually been out riding some, but the steel BMX style bike isn't ideal. We'll see how it goes with the Hotrock. The gear thing and breaks are going to be a fun learning curve.

Mike


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## Surfpoodi (Sep 14, 2011)

panamamike said:


> I plan on getting one of the shorter bars, 610 mm, hopefully taking an inch off will be o.k.
> 
> Plan on using stock stem.
> 
> Mike


I found the stock stem on the HR was rather heavy, and since I wanted to shorten the reach, and lighten the bike, I bought a new 30mm stem - you can find it if you search "ruben 30mm" on EBay.

One factor to consider with bars, which in my opinion, is more important than rise, is the sweep. The rise dictates how high the bars are, but that can also be adjusted with spacers, reversing the stem, or getting a stem with more rise.

The sweep will do two things. Sweep tends to put the hands in a more "neutral position" as compared to a pure straight bar. Also more sweep will shorten the effective reach, bringing the bars closer to the rider.

So, in my case, as I was trying to make a HR 20 work for a 42" boy, I used a very short stem (30mm), and bars with a fair amount of sweep to do everything I could to shorten the cockpit.

Hope that helps.


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## panamamike (Sep 11, 2008)

*Questions about some recommended parts...*

I've been doing some reading/research on bike build parts used by forum members. I did some reading about a few of these parts and was a bit surprised to find some potential issues. I wanted to see if people with experience could provide some insight.

1: Kenda Small Block 8 tires: Apparently more of a BMX tire, not a concern but read that they are prone to punctures as well as potentially comming off the rim. I know some reviewers can be a bit dramatic, I'd like to get some feedback on these issues. I also noted that there are some tire thorn guards, maybe that would help avoid the issue?
Any other tire recommendations? Also noted they do poor in wet weather...

2: Ruben 30mm stem: Again, designed for BMX, also didn't find any reviews, I'm guessing this is a new company? Anyone have positive feedback on how it compares to other quality BMX stems?

3: Seatpost 0 vs setback: I found a couple cheaper carbon seatposts but most are 0 degree no setback. I know ultimately it's about fit, but wanted to know if it's possible to add a setback to a 0 set post. I saw a video that mentioned something called "butt buddies" but had no luck doing a search, not to mention the alternative meaning to this phrase. I noticed setback varies quite a bit from post to post, hoping there was a way to address this when fitting the bike.

4: Grips: I tried some ODI's as listed in one of the builds. They didn't exactly fit, The lock didn't match the stock 7 speed shifter. I don't see an obvious way of making sure the grip matches the shifter lock. Also having trouble finding the right size grips. Being one long one short.

Mike


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## Surfpoodi (Sep 14, 2011)

Those are all parts I've run.... So I'll give a quick rundown.

I ran the SM8 for years as a semipro XC racer in tons of races, including some serious super D races as tubeless tires, and they worked great. I got my boy the wire 1.9" for his Hot Rock. They weigh just under 400g, and they seem like a good price point for a tire for a little guy. Light and decently supple, so I think they are a good choice if you are looking to upgrade rubber.

I got the Ruben 30mm stem on eBay. The seller was good to work with, and they shipped fast. The stem seems plenty burley for a little rider (or frankly a big rider). It weighs about 150g, and they will ship other colors that they don't currently have listed on eBay, just write them.

A 0 setback seat post would be perfect IMO for a small rider. I have a light carbon setback post on my boy's HR, and have it set all the way forward. My boy is mini, but with the setback, I need to do everything possible to get the seat forward to keep the seat in a reasonable position.

There are specific grips for Gripshift set ups. They are not symmetrical. You can cut a standard grip, but they won't quite mate up with the grip shift perfectly. Biggest thing for small hands is a thin and narrow grip, IMO.

Good luck....


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## m-dub (Apr 22, 2005)

AME Mini grips are the thinest I have found and cheap on e-bay. You can cut the flange off if you need shifter clearance. The ODI's are real thick for little hands.


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## rkt88edmo (Mar 28, 2004)

Surfpoodi said:


> So, in my case, as I was trying to make a HR 20 work for a 42" boy, I used a very short stem (30mm), and bars with a fair amount of sweep to do everything I could to shorten the cockpit.
> 
> Hope that helps.


So which bar did you go with? My girl is petite so I'll need to do everything I can to reduce the effective length. She's still opting to ride the 16" just because the 20" is so heavy.


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## panamamike (Sep 11, 2008)

Surfpoodi said:


> Those are all parts I've run.... So I'll give a quick rundown.
> 
> I ran the SM8 for years as a semipro XC racer in tons of races, including some serious super D races as tubeless tires, and they worked great. I got my boy the wire 1.9" for his Hot Rock. They weigh just under 400g, and they seem like a good price point for a tire for a little guy. Light and decently supple, so I think they are a good choice if you are looking to upgrade rubber.
> 
> ...


O.K. found some SRAM grips that should be the right size. I'm having trouble finding the Kenda Small Block 8 with Kevlar as well as associated intensity tubes, anyone know of a good place to find them?

Regards,

Mike


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## Surfpoodi (Sep 14, 2011)

rkt88edmo said:


> So which bar did you go with? My girl is petite so I'll need to do everything I can to reduce the effective length. She's still opting to ride the 16" just because the 20" is so heavy.


I have a lot of old 25.4 bars kicking around the place. I put some no name carbon fiber bars on his bike, and cut them down a bit.


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## Surfpoodi (Sep 14, 2011)

panamamike said:


> O.K. found some SRAM grips that should be the right size. I'm having trouble finding the Kenda Small Block 8 with Kevlar as well as associated intensity tubes, anyone know of a good place to find them?
> 
> Regards,
> 
> Mike


I ordered the SM8 from Universal Cycles. Light tubes from JR's.

There was a terrific post here a few months ago with weights, costs, and sources for a bunch of tires. I don't know how to search the archive, but it was a great summary of the options.


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## panamamike (Sep 11, 2008)

Surfpoodi said:


> I ordered the SM8 from Universal Cycles. Light tubes from JR's.
> 
> There was a terrific post here a few months ago with weights, costs, and sources for a bunch of tires. I don't know how to search the archive, but it was a great summary of the options.


Yeah, I actually found their site, but they only had one tire available. Thanks for the tip on the previous post, I think I found it tire weight and cost

Regards,

Mike


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## SRALPH (Jun 27, 2008)

1: Kenda Small Block 8 tires: Apparently more of a BMX tire, not a concern but read that they are prone to punctures as well as potentially comming off the rim. I know some reviewers can be a bit dramatic, I'd like to get some feedback on these issues. I also noted that there are some tire thorn guards, maybe that would help avoid the issue?
Any other tire recommendations? Also noted they do poor in wet weather...

SB8 ARE A FAST ROLLING TIRE IN DRY/HARDPACK. THEY TERRIBLE IN LOOSE AND WET. NEVER HAD ONE POP OFF BUT THEY ARE SCETCHY IN THE WET

2: Ruben 30mm stem: Again, designed for BMX, also didn't find any reviews, I'm guessing this is a new company? Anyone have positive feedback on how it compares to other quality BMX stems?

I DON'T KNOW RUBEN, BUT I PICKED UP A 35MM STRAIGHTLINE PINCH STEM FOR MY DAUGHTER'S TREK (STOCK WAS 60MM). GREAT STUFF AND IT WAS PINK AND 1/2 PRICE

3: Seatpost 0 vs setback: I found a couple cheaper carbon seatposts but most are 0 degree no setback. I know ultimately it's about fit, but wanted to know if it's possible to add a setback to a 0 set post. I saw a video that mentioned something called "butt buddies" but had no luck doing a search, not to mention the alternative meaning to this phrase. I noticed setback varies quite a bit from post to post, hoping there was a way to address this when fitting the bike.
I WENT WITH AN EL CHEAPO NO SET BACK POST AND CUT IT DOWN AS SHORT AS POSSIBLE (ABOUT 2/3 OF THE POST REMOVED)

4: Grips: I tried some ODI's as listed in one of the builds. They didn't exactly fit, The lock didn't match the stock 7 speed shifter. I don't see an obvious way of making sure the grip matches the shifter lock. Also having trouble finding the right size grips. Being one long one short.
ODI LOCKONS IN THE TWISTER LENGTH STILL NEED THE RINGS ON BOTH ENDS. THEY DON'T MATE UP NEATLY TO THE TWISTER, BUT CLEAN ENOUGH. THE RUFFIAN VERSION IS THE THINNEST THEY MAKE. IF YOU ARE KEEPING A TWIST SHIFTER, DEFINITELY GO WITH A LOCKON OR GLUE/WIRE THE GRIPS ONTO THE BAR


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## haasberk (Sep 13, 2012)

*Stem/headset for Hot Rock*

Two years ago I bought an used Hot Rock Specilalized for my son (it may be from 2004 or so; the previous owner hardly used it). The wheel size is 20" (without tires; with tires it is about 23"), so I assume this is a 20" bike. Someone stole the parts that connect the steer to the frame (the steer, brakes etc are still in tact). I think that means a thread less (?) stem, a headset and maybe dividers. The local bike store told me it is a $ 100 to fix this. Does any one know what parts I need and how to fix this for less money? The outside diameter of the pipe that comes out of the frame is app. 30 mm / 1.18 inch.
Marya


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## Surfpoodi (Sep 14, 2011)

Hard to know exactly what you need based on your description, but it sounds like maybe all you need is a stem. Here is a stem that would work just fine as a replacement.

Amazon.com: Dimension Threadless Stem: 60mm; 83/97 Degree; 25.4; Black: Sports & Outdoors


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## NYrr496 (Sep 10, 2008)

Lizard Skins just came out with a new grip called the Bear Claw. It's their smallest diameter grip.


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## indianadave (Apr 27, 2010)

Haasberk.
Surfpoodi is probably correct.
You can shop Ebay and find a stem for 1-1/8 headset, (the size of the steer tube it attaches to) 25.4 bar diameter (diameter of the handlebars) 50mm-60mm long stem. Any longer may be too long and your kid will be stretched out likely. I got a 50mm for my daughters older Hotrock, and it works fine.
The nice thing about these Specialized is that anything from an adult bike will bot on to them. Very easy to upgrade.


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## Surfpoodi (Sep 14, 2011)

Incidentally, I put a 30mm stem on my son's HR, and it works great for him. He is not yet 5, so a smaller stem made sense. I seem to remember the stock stem I removed was 60mm.


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## haasberk (Sep 13, 2012)

*Stem / Headset HR*

surfpoodi/indianadave, thx for your replies. I think I need something to fixate the pipe that goes from the front fork / front wheel through the frame. See attached pic (hopefully that works). It also looks like if you can put a screw into that pipe. What do you think?


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## NYrr496 (Sep 10, 2008)

Dude... That pipe is the steerer tube. The top of the headset goes on and then the stem cinches it all together. 
Not trying to be mean, but if you're not skilled at this, take it to someone who is, like the bike shop. 
You don't want your kid to crash because he lost his or her steering.


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## Surfpoodi (Sep 14, 2011)

I'll second NYrr476's comments. Take it to a shop if this is unfamiliar terrain. I will say that $100 to get a cheap stem and installation seems out of line. I'd suggest a second opinion. Unless you are missing headset parts I'd think you should be out the door in 20 minutes with a total bill under $50.


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## haasberk (Sep 13, 2012)

That's the thing, the headset is gone too. Trying to figure out what parts I need (not familiair with the English terms) and where to get them for an affordable price. But if everyone tells me that 100 is normal in the US to get this fixed, I may have too.


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## NYrr496 (Sep 10, 2008)

I usually buy Cane Creek S-3 or now the 40 series headsets for kid's bikes. 
My son's latest bike has a blue frame and he wanted a blue headset... The bike shop got me a blue anodized one that was around 40 bucks. The brand is escaping me at the moment, but it has nice bearings and seals and spins silky smooth. 
I would think you could get a headset and a stem and get them installed for well south of 100 bucks.


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## logbiter (Dec 30, 2003)

haasberk said:


> That's the thing, the headset is gone too. Trying to figure out what parts I need (not familiair with the English terms) and where to get them for an affordable price. But if everyone tells me that 100 is normal in the US to get this fixed, I may have too.


You definitely need a new stem ($20-50), some spacers ($5) and at least new top half of the headset (bearings, cover & stem cap). A new headset runs ~$30 for a cheapo at the LBS. The should be a "star-fangled nut" inside the steerer tube of the fork, which a stem cap threads into, if not, factor in another $5-10 for a shop to put one in. Some headsets come with these nuts.

A decent local shop might be able to scare up the half headset needed out of spare parts. Sounds like everything should be 1 1/8" diameter threadless. The handlebar is probably 25.4 diameter where the stem clamps on, but could possibly be 31.8mm diameter.

For the uninitiated, the headset install/removal needs some specialized tools. A shop shouldn't charge more than $15-25 for install of a new headset & stem. Park tools website has a good repair area to show you how to work on stuff.


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## haasberk (Sep 13, 2012)

Thanks guys, that is very helpful!!


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## spyguy (Apr 18, 2006)

does anyone know what stem would fit the specialized hotrock 16"?


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## indianadave (Apr 27, 2010)

It's a 1-1/8" steer tube, and likely a 25.4 handlebar. I'd get the shortest you can find, likely a 50mm length. They are plentiful, and 25.4 stems are cheap since most all grownup bikes have gone to the 31.8 daiameter handlebars.
Old downhill stems are short, but usually pretty beefy.
I got one cheap, then "milled out" the sides to lighten it up. It's light, and plenty strong for my kid.


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## spyguy (Apr 18, 2006)

thanks!


indianadave said:


> It's a 1-1/8" steer tube, and likely a 25.4 handlebar. I'd get the shortest you can find, likely a 50mm length. They are plentiful, and 25.4 stems are cheap since most all grownup bikes have gone to the 31.8 daiameter handlebars.
> Old downhill stems are short, but usually pretty beefy.
> I got one cheap, then "milled out" the sides to lighten it up. It's light, and plenty strong for my kid.


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