# Hydraulic Discs for Kids



## Vermont29er (May 27, 2006)

I'm getting my daughter a Trek Roscoe 20 for her 7th birthday. It comes with cable discs, but I know how much easier it is to use hydraulic discs and I'd like to set it up with some hydros. Can anyone recommend some hydraulic discs that have levers that are good for small hands?


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## svinyard (Aug 14, 2017)

Vermont29er said:


> I'm getting my daughter a Trek Roscoe 20 for her 7th birthday. It comes with cable discs, but I know how much easier it is to use hydraulic discs and I'd like to set it up with some hydros. Can anyone recommend some hydraulic discs that have levers that are good for small hands?


Our spawn came with Hydraulic Tektro brakes. They work fine ergnomic and brake wise.


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## SactoGeoff (Aug 11, 2017)

The cheap Tektros are fine. But Shimano XT or Deore is ideal. The lever itself is shorter so the possibility of 2 finger braking is there. Reach is fully adjustable on almost everything.


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## jestep (Jul 23, 2004)

SactoGeoff said:


> The cheap Tektros are fine. But Shimano XT or Deore is ideal. The lever itself is shorter so the possibility of 2 finger braking is there. Reach is fully adjustable on almost everything.


Was going to suggest anything current shimano. I've seen the Deores as low as about $50 for both the brake and the lever.


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## svinyard (Aug 14, 2017)

jestep said:


> Was going to suggest anything current shimano. I've seen the Deores as low as about $50 for both the brake and the lever.


I'd go with SLX (is this Deore now?). IIRC they don't have the on/off-switch braking issue that the old XT's do (thankfully they fixed it in their new brake release). For a kid you definitely want something with a little feel/feedback for it if they are riding anything dangerous.


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## stevelim (Jul 23, 2008)

Magura MT2 is another option. Cheap ($50 a side), lighter than Deore's, mineral oil, reach adjustable, and short lever for small hands.


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## jestep (Jul 23, 2004)

svinyard said:


> I'd go with SLX (is this Deore now?). IIRC they don't have the on/off-switch braking issue that the old XT's do (thankfully they fixed it in their new brake release). For a kid you definitely want something with a little feel/feedback for it if they are riding anything dangerous.


Deore's are one step below SLX.

I think only the XT and XTR had the bite issues, I haven't heard of them in Deore or SLX. From personal experience, I have thrown myself off my bike because of the XT's.


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## RMCDan (Feb 28, 2008)

General brake-buying advice that applies doubly here: Never buy a brake that doesn't have tool-less reach adjust.

SLX would be a good option for sure. No complaints with the Guide Rs on my sons Rokkusuta or the Hayes Prime that came on his Flow.


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## RAKC Ind (Jan 27, 2017)

RMCDan said:


> General brake-buying advice that applies doubly here: Never buy a brake that doesn't have tool-less reach adjust.
> 
> SLX would be a good option for sure. No complaints with the Guide Rs on my sons Rokkusuta or the Hayes Prime that came on his Flow.


Why is tool-less reach adjustment important? How many people adjust reach after initial settings especially on the trail? 1 in 100 maybe, probably even less. I ride all around the Midwest with h a nice variety of trail styles and terrain. Literally NEVER touch my reach adjustment after initial set up. So tool-less is useful for few but mostly gimick.

Sent from my SM-G950U using Tapatalk


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## benyl (Jun 2, 2016)

I upgraded the brakes on my bike to Zee.

My son's Scott Scale 20+ got the Deores. I kept the 160mm rotors from the cable Tektro brakes. He didn't need the 180s from my bike.










Sent from my iPhone using Tapatalk


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## RMCDan (Feb 28, 2008)

RAKC Ind said:


> Why is tool-less reach adjustment important? How many people adjust reach after initial settings especially on the trail? 1 in 100 maybe, probably even less. I ride all around the Midwest with h a nice variety of trail styles and terrain. Literally NEVER touch my reach adjustment after initial set up. So tool-less is useful for few but mostly gimick.


-The premium to get tool-less is usually minimal. SLX is +$12 over Deore on Jenson right now. The question is not why, but why not.
-I have small hands so I'm finicky about reach.
-Kids are more likely to need the reach tweaked. Also, see above, they have small hands too. 
-It's recommended to back the reach adjustment all the way out before bleeding. Much easier with tool-less.
-IME, most tooled reach adjusters are placed in terrible locations that aren't conducive to multi-tools and are a general PITA.


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## svinyard (Aug 14, 2017)

RMCDan said:


> -The premium to get tool-less is usually minimal. SLX is +$12 over Deore on Jenson right now. The question is not why, but why not.
> -I have small hands so I'm finicky about reach.
> -Kids are more likely to need the reach tweaked. Also, see above, they have small hands too.
> -It's recommended to back the reach adjustment all the way out before bleeding. Much easier with tool-less.
> -IME, most tooled reach adjusters are placed in terrible locations that aren't conducive to multi-tools and are a general PITA.


Crap, I just bled my son's tektro brakes without backing out the reach!! How big of a deal do you think it is? They seem to have a lot of lever throw even after a bleed...


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## RAKC Ind (Jan 27, 2017)

svinyard said:


> Crap, I just bled my son's tektro brakes without backing out the reach!! How big of a deal do you think it is? They seem to have a lot of lever throw even after a bleed...


I've never done it. Only because I ALWAYS forget lol. Never had a problem except of course you don't have full lever travel if needed during bleed which can take a tad more work to bleed.

It just makes it a little easier to get the air out is all, has 0 effect on performance since all that matters is air is out and they are working properly.

As for SLX vs deore, ya for $12 each it doesn't sound like much but with that level of thinking that starts to add up fast as that rule gets applied to everything. I have 2 boys, I'd be homeless if I went with "what's another $12" lol. Especially having to replace bikes every couple years at most. My oldest gets "hand me downs" from me. I upgrade he gets what came off if it's perfectly good. Youngest is just now really pedaling so I've got time before that bill starts racking up.

Sent from my SM-G950U using Tapatalk


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## svinyard (Aug 14, 2017)

Side note, I just topped off the reservoir at the lever then rolled back the lever adjustment (out). This brought the bite back to normal, tho when I adjusted the lever throw after screwing it all down again, then the bite was still pretty late and only a little better. Seems like its just the brakes. Not perfect for tiny hands but fine for my larger 6yo, I'll just leave the levers out a little extra.

being that we are dealing with little, light kids...it'd be nice to just get a nice XC brake that is really light but not super expensive either.


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## Tjaard (Aug 17, 2007)

The Deore brakes on my 7 year olds Riprock work pretty well for her. (Size L Specialized kids gloves).

For really young kids there is some merit to cable brakes too, since they don’t need a ton of brake power, so you can easily fine tune the balance betweeen reach, power and pad contact point.


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## SactoGeoff (Aug 11, 2017)

Tjaard said:


> The Deore brakes on my 7 year olds Riprock work pretty well for her. (Size L Specialized kids gloves).
> 
> For really young kids there is some merit to cable brakes too, since they don't need a ton of brake power, so you can easily fine tune the balance betweeen reach, power and pad contact point.


Except the amount of force necessary to pull the lever and create enough friction. Hydraulic is easier to pull and modulate.


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## Vermont29er (May 27, 2006)

I ended up going with Deore hydros based on the shop's recommendation of them along with folks here, and the nice short levers. The guys at the shop said it's easy to get a good tight bleed out of them, which will be important with the levers close to the bars.

I'll be sure to post some pics with her hands for reference when we get the bike.

Lucky kid, it's going to be a nice ride.


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## mnpikey (Sep 18, 2017)

What size rotors? Looking to switch out the brakes on my sons 24" Salsa to hydraulic. Wife's bike has Shimano Deore M506 brakes which I was thinking of upgrading to XT M8020s. Could use the Deores on the Timberjack then but am wondering about rotor size. His bike currently has 150mm front and 140mm rear rotors. Would those have to be changed too or would the M506s work with that rotor size?


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## TimTucker (Nov 9, 2011)

Guessing you'd be fine with the smaller rotors -- size is mostly determined by the position of the mounts on the frame.

On the hydraulic brake front, we're about to try Tektro HD-M745's on my son's bike -- I came across them looking for a budget set of 4 piston brakes for my wife's bike back in the spring:
https://www.tektro.com/products.php?p=236

As I started looking at specs for weight across various options, I wound up coming back to them -- they're close to XTR weight at slightly lower than Deore pricing (~$60 / side on eBay or $130 for a set w/ pads).

Basic specs:

4 piston
Mineral oil
251g front / 271g rear

Only question TBD is just how far down the reach will adjust.


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## CBaron (May 7, 2004)

TimTucker said:


> On the hydraulic brake front, we're about to try Tektro HD-M745's on my son's bike


Man I hope you have good luck with them. We had a pair on (different models) on my son's 20" MTB and hated them all around. Modulation wasn't good, the pistons were constantly sticking (and thus rubbing). I finally dumped them in the trash and bought a super cheap pair of Shimano.

Later,
CJB


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## TimTucker (Nov 9, 2011)

CBaron said:


> Man I hope you have good luck with them. We had a pair on (different models) on my son's 20" MTB and hated them all around. Modulation wasn't good, the pistons were constantly sticking (and thus rubbing). I finally dumped them in the trash and bought a super cheap pair of Shimano.
> 
> Later,
> CJB


The higher end Tektros seem to be of significantly higher quality than their low end oem models. So far so good on my wife's bike.

Before buying there wasn't much available info other than that Norco has had them on some of their bikes and the few reviews I could find seemed positive:
https://flowmountainbike.com/tests/tested-norco-range-a7-3/


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## mnpikey (Sep 18, 2017)

Thanks! Gonna have to pull the Deore brakes off my wife's bike and give them a try. Feels kind of ridiculous to spend so much effort on this 24" bike knowing he'll soon outgrow it for an XS 27.5" most likely. But, he loves riding and I want him to not have to deal with crappy gear......we're going to upgrade him from the Altus 8 speed 12-32 gripshift to 11 speed 10-42 M8000 XT this weekend. Hate the look on his face when he can't do a tough climb knowing he COULD do it if not for the gearing. Hopefully I can use that on something else when it comes time to sell this 24"....want to keep encouraging him to ride whenever possible!


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## twodownzero (Dec 27, 2017)

RAKC Ind said:


> Why is tool-less reach adjustment important? How many people adjust reach after initial settings especially on the trail? 1 in 100 maybe, probably even less. I ride all around the Midwest with h a nice variety of trail styles and terrain. Literally NEVER touch my reach adjustment after initial set up. So tool-less is useful for few but mostly gimick.
> 
> Sent from my SM-G950U using Tapatalk


I adjust mine every time I ride. Call it a nervous habit. I love the tool free reach adjust!


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## CeUnit (Jul 9, 2014)

+1 for tool-free reach adjust. One of my bikes doesn't have it, and I've been too lazy/unmotivated/busy to adjust it via allen key since it's a pain in the butt since the set screw is so close to the handlebar. Oh, and one is rounded out since it's so hard to get the key inserted perfectly. The round head allen keys help a bit...

On my other bike and my kids' bikes with tool free adjust, I've tweaked them several times, on the spot, and never had to wait to get-around-to-it. Worth it!

Friend of mine put the on/off XT brakes on his kid's bike and she's constantly skidding uncontrollably... lol.


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## ryder_bikes (Jul 20, 2020)

How close are people able to get the levers to the bars? I'm struggling to find something that will work for my 3 year old son. I just got the Prevelo Zulu Two Heir for him, but the stock Tektro hydraulic disc brakes can't be adjusted in close enough for his tiny hands. The closest we've been able to adjust them is 39mm from the grips to the outside of the levers (see attached photos), without losing braking power. I'd really like to find a solution that's 29mm or less.

Thanks for any help!



Vermont29er said:


> I ended up going with Deore hydros based on the shop's recommendation of them along with folks here, and the nice short levers. The guys at the shop said it's easy to get a good tight bleed out of them, which will be important with the levers close to the bars.
> 
> I'll be sure to post some pics with her hands for reference when we get the bike.
> 
> Lucky kid, it's going to be a nice ride.


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## TimTucker (Nov 9, 2011)

You can probably have room to adjusted the reach in a little further by slightly overfilling when you bleed so that it bottoms out a little sooner.

General process:

Sand down a bleed block so that it's a bit thinner
Insert bleed block and bleed as usual
Use piston press to push the pads back outward

Protaper Junit handlebars could also give you a few more mm to work with.

3yo hands are just really tiny, though.


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## jochribs (Nov 12, 2009)

Call me a retro grouch, but this is one of those areas that I think that bike would be better served by a set of mechanicals. Don't get me wrong, I'm all about hydros. 

At 3, power is not needed. It could be argued that discs aren't needed, but that's besides the point, and well, discs are already on the bike. 

With mechanicals, the levers can be adjusted in with the set screw ( I even placed a small plastic cap over the end of the set screw on my sons bike years back when the set screw wasn't long enough, worked perfect). Then the caliper can be adjusted to have the fixed pad as close as you can possibly get it to the rotor. Preloading the mechanical arm a smidge before clamping the cable (provides better feel than using the barrel adjuster) will give you the free throw that you want. Just need to do a little trial and error. 

The issue with trying to over fill the system is that you're asking for trouble/leaks. And trying to advance the pistons for less pad clearance is a hit or miss endeavor. May feel good this time, may feel like crap the next. With mechanicals, it's not going to go out of adjustment...you're not trying to balance fluid in one part of the system. Plus, kids at that size dump the bike, and they dump it often. The hits to the end of the lever are hell on the seal around the piston rod. 

If it were me, I'd pull those brakes and put on a set of mechanical levers/calipers. 

I do agree that the Junit bars are a good idea.


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## svinyard (Aug 14, 2017)

Ah I didn't see the part about needing the pads to engage sooner so that you can bring the levers even further in. You can do a beer can shim for the pads. Overfilling cheap brakes could get ugly over time but cutting a shim out of a beer can will get those pads to engage sooner. Its almost just like having thicker pads and is a quick fix. Cut the shim to match the brake pad (along with the mounting hole) and insert into the caliper.


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## jochribs (Nov 12, 2009)

svinyard said:


> Ah I didn't see the part about needing the pads to engage sooner so that you can bring the levers even further in. You can do a beer can shim for the pads. Overfilling cheap brakes could get ugly over time but cutting a shim out of a beer can will get those pads to engage sooner. Its almost just like having thicker pads and is a quick fix. Cut the shim to match the brake pad (along with the mounting hole) and insert into the caliper.


Actually not a terrible idea. But, it does nothing to solve that the levers can't be adjusted in enough. It just makes the throw, on levers that are too far out, shorter.

So the question is...how do you 'reliably' shorten the throw on hydro levers that are already adjusted all the way in? Not sure there's a way.

**Unless there is a point on the levers where the lever meets the resevior body and some sort of shim can be placed there. A section of zip tie, a plastic wedge of some sort. Hot glue it in to place etc. Bleed from there.

Quite a bit of faff. I loathe mechanicals, but I think they're superior for a 3 year old.


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## svinyard (Aug 14, 2017)

Yeah I thought his levers could go in more but that they then pulled to the bar without full braking power. Maybe the shim works for that. 

I actually have the problem you just mentioned. I can't bring the lever in any further...BUT there is a lot of empty lever throw before the pads contact the rotor. So yeah McGrubering something where the lever meets the reservoir would be the ticket.


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## TimTucker (Nov 9, 2011)

jochribs said:


> Actually not a terrible idea. But, it does nothing to solve that the levers can't be adjusted in enough. It just makes the throw, on levers that are too far out, shorter.
> 
> So the question is...how do you 'reliably' shorten the throw on hydro levers that are already adjusted all the way in? Not sure there's a way.
> 
> ...


If there's room to move them further inward, it's possible that you could fashion a lever extension out of something like Sugru and/or metal to bring the actual contact point closer to the bars:
https://sugru.com/sport-outdoor/9-ways-to-improve-your-bike-with-sugru

Alternately, if you can get the dimensions down you could have CNC levers made with a little different geometry.

I've been toying around with the idea of a custom headset adapter to use a Cane Creek dampening headset on my Stache and Xometry looked like one of the more affordable (~$60 or so for a small part, with most of the cost being setup -- cost per piece went down to about $10 each if I did more)


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