# changing shifters on kids mountain bike



## gene22 (Feb 14, 2008)

Hello,

My son has a Trek 20" mountain bike with a 6 speed grip shifter. Can this shifter be replaced with a rapid fire shifter?

Thanks


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## Call_me_Clyde (Oct 27, 2004)

*Probably not*

Wow, a six speed? That's going to be tough to find. Keep your eyes peeled on ebay, craigslist, etc., but my guess is you're going to have a difficult time fidning it, if indeed there is such a thing still in existence.


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## laurenlex (Sep 13, 2006)

Rapidfire shifters started out 7 speed. So you need a new cassette or freewheel, which MIGHT not fit on the hub.

I think they put gripshifters on kids bikes because they might not have long enough fingers to work the triggers.


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## Arkon (Apr 27, 2004)

Yes they do make 6 speed trigger shifters. You'll have a hell of a time finding them in a quality good enough for adults but for kids bikes they are easy enough to order. I actually purchased a 7 speed trigger shifter on for my son's bike today and in the bin were 2 six speed shifters.


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## mtnbiker72 (Jan 22, 2007)

Never even when working as a mechanic in bike shops from 1995-2003 did I see 6 speed rapid fire+ shifters. I recall seeing Suntour Accushift 6 speed shifters (not Shimano spacing compatible) and there might have been some 6 speed original Shimano Rapidfire (two thumb levers). But that stuff would be pushing 15-20 years old these days. Grip shift and Shimano Tourney 6 speed top mounts are your choices


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## Tony G UK (Dec 11, 2006)

Converted my younger boys 20" trek just a couple of weeks ago. Its a trek MT60.

Couln't find suitable 6-speed shifters, so went for a 7 speed setup. The cassette fits no problems.

My youngest boy can now easily shift gears, and is doing some quite serious MTB riding. So, a worthwhile upgrade.


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## Razorfish (May 9, 2008)

Good work. I just changed my daughter's last night.


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## daleksic (Aug 26, 2007)

What age are your kids? My son is about to turn 7 and he wants (me) to upgrade to a Mountain Bike with gears (just like Daddys'). My LBS has a Giant 20", but i wasn't sure if I should go with something else. The Giant feels so much heavier than his current 20" Hotrock. I want to get him something really light if possible.


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## dh1 (Aug 28, 2004)

daleksic said:


> What age are your kids? My son is about to turn 7 and he wants (me) to upgrade to a Mountain Bike with gears (just like Daddys'). My LBS has a Giant 20", but i wasn't sure if I should go with something else. The Giant feels so much heavier than his current 20" Hotrock. I want to get him something really light if possible.


There are lightweight kids MTBs. Scott, Marin, Fisher, etc. I can't comment on the 20" hotrock. I bought my son (now turning 11) a Marin Bayview Trail when he turned 7. His younger brother is now using it, and about to pass it to his younger sister. The bike is lightweight and built like a MTB, not a kids toy. Nothing gimicky about it, although the components are not all that great.

My only complaint is that the Alivio shifters, especially the front shifter, are hard for kids to operate with their thumbs. I have actually had to replace the shift housing because my older son actually had the housing split when he was trying to shift.

If you don't like the Giant, keep looking. I really like my son's Marin, but we saw a guy with his son at the trailhead last Friday....they had a youth sized Scott that was real nice.

At your son's age, I would consider a 24" wheeled bike...unless he is really short. The 20 will be to small for him within a year.


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## fritZman (Jan 9, 2004)

daleksic said:


> What age are your kids? My son is about to turn 7 and he wants (me) to upgrade to a Mountain Bike with gears (just like Daddys'). My LBS has a Giant 20", but i wasn't sure if I should go with something else. The Giant feels so much heavier than his current 20" Hotrock. I want to get him something really light if possible.


My @ 7 y/o son went from a 20" Hotrock to a Brodie Menace.

Awesome rig.


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## daleksic (Aug 26, 2007)

Now that's a cool bike. It's actually a bike, not a toy. Not that my sons 20" is a toy either but it's BMX style and not MTB style. I'll check the websites, as the LBSs only carry Specialized or Giant, and I wasn't thrilled with any of them. I guess he's going 24"...


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## barelfly (Jun 27, 2008)

I also was thinking of switching out the grip shifter on my daughters bike. It seems like you have to get just perfect or it chatters a bit. We got this for her about a month ago, she loves it! Already done a few 15 mile rides with her at 7y/o.

Is switching out the grip shifter an easy task, considering I don't have experience with bikes? or is this something the LBS should do?


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## dh1 (Aug 28, 2004)

barelfly said:


> I also was thinking of switching out the grip shifter on my daughters bike. It seems like you have to get just perfect or it chatters a bit. We got this for her about a month ago, she loves it! Already done a few 15 mile rides with her at 7y/o.
> 
> Is switching out the grip shifter an easy task, considering I don't have experience with bikes? or is this something the LBS should do?


Don't bother changing the shifters. The problem you are experiencing is due to cable stretch and likely nothing more. THis happens after your bike has been in use for several hours, and when the cable stretches (even 1mm) the derailleur will not line up with the cog precisely. The rattling you hear is the side of the chain rubbing on the next smaller cog.

The fix is easy. You can do it yourself, or take it to the bike shop. I suggest trying it yourself first, and if you really botch it up the LBS can adjust it for you....and the cost for them to fix your botch job will be the exact same as fixing the current problem.

Here is my logic: cost of a tune up at the LBS = $55. Cost of making the adjustments yourself =$00. The first time I did it, I had to screw around quite a bit to understand how it worked, but now I can tune up my entire bike (shifting, braking, lubrication, simple truing of wheels) in about 20 minutes from tip to tail.

Here is how you do it. The rear derailleur cable will have an adjuster (called a barrel adjuster) at the end by the shifter and the end by the derailleur. If you turn either of these adjusters counter clockwise it will begin to tighten the cable. Tighten in 1/4 turn increments until the chain sounds smooth while pedaling briskly. Then to ensure proper adjustment, shift it up and down through each of the gears while pedaling at a steady pace. Once you get it dialed in, the shifting should be clean and responsive. If the shifting is sluggish, you probably tightened it too much, so relax the cable 1/4 of a turn.

What I listed here is the fast and dirty method, but read up on it. Here are a couple great links:
https://sheldonbrown.com/gearing/index.html
https://www.parktool.com/repair/byregion.asp?catid=53&imageField2.x=21&imageField2.y=1

The front derailleur typically only has one adjuster at the shifter. Both derailleurs have limit screws that set the high and low travel limits. These screws when set correctly will allow the chain to go the largest and smallest chainrings and cogs, without shifting off the top or bottom. Usually the set screws are set and forget....only needing adjustment if you remove or change the derailleur, or if something is forced out of alignment.


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## cristobal41 (Mar 25, 2004)

*Kid height*



fritZman said:


> My @ 7 y/o son went from a 20" Hotrock to a Brodie Menace.
> 
> Awesome rig.


Hi, Fritz,
Nice bike. 
How tall is your son? Mine is slightly under the average and at 6.5 yo a 24" wheeel bike is too big for him. On the other side, a 20" will be overgrown in one year. 
I want a bike properly fitted for him, but paying 325$ for a single year bike is hard to do.
Regards.


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## dh1 (Aug 28, 2004)

cristobal41 said:


> Hi, Fritz,
> Nice bike.
> How tall is your son? Mine is slightly under the average and at 6.5 yo a 24" wheeel bike is too big for him. On the other side, a 20" will be overgrown in one year.
> I want a bike properly fitted for him, but paying 325$ for a single year bike is hard to do.
> Regards.


My son is a short 6 year old and rides a 20" wheeled BMX. I don't think he will fit a 24" wheeled bike until he is 7 1/2 or 8.. My older sons were taller at this age.


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## Tjaard (Aug 17, 2007)

dh1 said:


> There are lightweight kids MTBs. Scott, Marin, Fisher, etc. I can't comment on the 20" hotrock. I bought my son (now turning 11) a Marin Bayview Trail when he turned 7. His younger brother is now using it, and about to pass it to his younger sister. The bike is lightweight and built like a MTB, not a kids toy. Nothing gimicky about it, although the components are not all that great.
> .


Specialized does make the Hotrock in 24" sizes. If he's tall enough you could get him the A1 FS in 11" frame size. The make 2 24" bikes the Hotrock7 speed and the A1 FS, the A1 FS is the lighter weight frame and 'real mtb' style bike, basic components but similar to an entry level adult mtb, including a lockout fork and double wall rims with machined sidewalls,


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## Harrier (May 5, 2008)

cristobal41 said:


> Hi, Fritz,
> Nice bike.
> How tall is your son? Mine is slightly under the average and at 6.5 yo a 24" wheeel bike is too big for him. On the other side, a 20" will be overgrown in one year.
> I want a bike properly fitted for him, but paying 325$ for a single year bike is hard to do.
> Regards.


I have to question the urge to buy new. Go on craigslist and look for a 20" from a reputable company. Don't stress that it is not the lightest bike on the planet. With the money you save, get a better bike when they are ready for a 24"

Spending $300+ on a 20" is nuts.


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## cristobal41 (Mar 25, 2004)

*Final solution*

Hi,
After searching and studying thoroughly the market and its different options I finally got a KTM Wildthing 20" (http://www.ktm-bikes.at/2009/at/detailBike.php?Bike=wildthing20&kat=Kid). Amazing bike. It is certainly pricey (500 USD), but it is worth the effort.

Reasons? The three rings crankset. For a 6 years old kid dealing with a single or double front ring set is hard to do as the max gear ratio is 36x34= 1,05 (Cube Kid 200). In our regular bikes we have a 32X34=0,94 if we only use the middle front ring. If we engage the granny, we reach a 22x34=0,64 what makes things easier for us. So, I want the same easiness for my son.

The only three front rings kid bikes available are the aforementioned KTM and also the Ibex Alpine 320 K (http://www.ibexbikes.com/Bikes/ALP-320K-Details.html) but this last one is not easily available in USA and much less in Spain. You are also to add the shipping and customs.

The RST fork works quite properly. It is operative under a 44 pounds weight. It is not common among kids forks.

Consequently, I am very glad for the bike itself and for my son. It's not been easy to find it. I luckily could put my hands on the merely only one available at the moment in Spain.

Cons? Of course. Its 42/34/24 and 11-28 combo is not enough for real mountain biking and trail riding for a avid 6 years old kid. So, I swapped the original cassette for a 14-34 one that helps when climbing is the matter and is not too fast when flat terrain is to come. The Tektro brake levers are clearly short and difficult to operate specially right by the side of the bulky Shimano twist shifter. Furthermore, the screw that allows you to choose the lever reach is weak and easy to make round even using quality allen wrenches. I will change them for a regular allen or torx head ones. (http://www.mx1.co.uk/content/Info/KTM_Sport_87.pdf). Regarding the brakes, I always do the same: I swap the thick braking wires for a derailleur ones. They are much thinner and you cannot imagine how buttery the brakes work with this cheap and easy change.

I just can say that I am very happy to see how my son improved his biking skills right from the moment he threw his leg on his KTM. He comes from a light BMX bike that I thought it would be a real option for mountain bike due to its lightness. Wrong. Its geometry doesn't help to pedal as the boy is to do it standing on the pedals all the time or incorrectly positioned on the saddle that is too close to the long crank arms. Due to its awkward position he had to bend his knees when the pedal was in the upper part of its stroke and almost reached his chest for not to mentioned the hard and only gear ratio.

This situation made my son to neglect the bike as he didn't feel motivated and keen to ride. Not now. He feels capable now and ready for our next Saturday real first serious ride that will be 13 miles long including Camelbaks and sandwiches.

Cannot wait.

Best regards.


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