Maureen

My 3 year old has a Specialized bike with 18" wheels. We recently took of the pedal brakes to lighten the bike up and put on U brakes. The hand pressure required to stop the bike on flat ground entirely too high for my sons little hands. I looked at the promax V brakes on the micro mini and they required only light pressure to stop in a similar situation, and my son was able to stop it. I in addition to a few other people have tried adjusting the brakes to no avail. I do not want to spend the money on a new bike. Should I try the Promax V brakes? Will changing to V brakes help or is it possibly the bike/18" wheels, and I just need to bite the bullet and get him a new bike? Also we live at the top of a big hill!

hypersnazz

There are a number of things you can do to improve braking power, but there are just as many equipment factors involved. Be aware that the mounts for V-brakes and U-brakes are NOT interchangeable.

- make sure all braking surfances are as clean as possible. Chrome still makes the stickiest braking surface; if your rims are machined alloy or anodized, braking power suffers. Sometimes a little, sometimes a lot. Simple Green works extremely well and is safe for rims, pads, children and other Living Things.

- believe it or not, braking power is not necessarily a factor of how *much* pad touches the rim. If you don't believe me, go take a look at your high school physics book in the chapter on friction. Force applied to the rims is force, no matter how large the surface area. The greater the surface area the slower your pads will *wear*.

- pad compound, on the other hand, *does* matter. Softer compounds tend to wear faster but stop harder. Salmon Kool-Stops might be a good bet.

- loosen the brake springs to the point where they just barely return when the lever is released. The heavier the spring pull is, the heavier the lever pull to overcome them is. Additionally, you can either drip Tri-Flow into the stacks or disassemble, clean and lightly grease the brake bosses with reg'lar old bearing grease.

- Tri-Flow in the cable housing is also not a bad idea, and guess what? The stuff works pretty well by capillary action, meaning you can just drip a fair amount of it onto the exposed cable near where it enters/exits the housing and it'll be pulled in.

- Sometimes it's worth it to disconnect the cable and pull the lever just to see if you're losing power in the brake or in the cable. If it's the cable's fault, try the above lubing technique, or replace the cable altogether with new, quality stuff.

Hope that helps!

Brian

If you're taking the U Brake off to grease the posts, take a tip from Mr. OCD himself. Get a long strip of cloth and a bit of metal polish, and polish the posts up before applying the grease. Just be sure to remove all the polish before greasing. That and the salmon Kool Stops, with a properly adjusted brake, are about as good as you'll get. It may just be that his hands are too little to work the brake effectively though.

Keep us updated - we like to know if our advice did any good.

Maureen

Thank you for your help! I am off to the bike store today to give it a try and will let you know how it goes. What you said makes a lot of sense, and I am invigorated with new hope! Thanks again!

mude

he's three and already riding a two wheeler?

racersk66

2 wheeler for me at 4, but 3 thats pretty damn cool.

Brian

My neighbours 3 year old is on the track with a training wheels. You two were just slow I guess.

mude

training wheels at 3....yes
two wheels....no

Brian

On the track at 3.

mude

...with training wheels

Brian

You're jealous.

Maureen

Thank you again for your help! Here's what happened..... I got the Cool Pads, cleaned all of the areas very well, oiled the areas that you spoke of, and adjusted the springs so the pads just let off when the lever has no pressure on it. It definately made a big difference; the oil especially! I think he should be able to make it work, but it will take some practice. I can now stop it with my pinky on a significant slope (a lot of pressure from my pinky mind you). This was definately not possible before. My son is not ready yet to head down the hill with hand brakes, like he did with the petal brakes, but I am hopeful. The V brakes on the micro mini will not work on his bike. Even with all of the adjustments the U brakes are not as easy as the V brakes. This was very educational. I think I have to keep on the lookout for a used micro mini, but I think this will work for a while.

Also, he is not using training wheels. He got off of them at about 3 years and 3 months. The motivation was taking him to the BMX track. Initially he had no interest in riding on 2 wheels, then once I took him to the track the training wheels came off. Although he is very very frustrated about not making it around the track (hence the brake changes) he really loves it!

Thanks again!

hypersnazz

V-brakes have a huge mechanical advantage over U-brakes simply by merit of design. The reason U-brakes are common on BMX bikes is mostly feathing/modulation and the ratio of lever pull to arm throw is smaller, allowing the pads to clear warped, bent-up wheels without rubbing. Freestyle simply doesn't *demand* a lot of stopping power, even dirt jumping, so V-brakes are only really common on race bikes. Even then your braking power is usually limited by tire traction, not by how strong your brakes are. If the tire locks up, a stronger brake is useless.

Brian

Snazzy makes a good point. I rode my cruiser to work Saturday. K-Rad's on wet pavement and high speed turns make for big dramas. I whipped around a corner, there was a car coming, and I just slid across the lane...

Maureen

Now that I am thoroughly impressed...... Hypersnazz, I would like to ask you to recommend a good BMX bike shop in the valley. I am in Gilroy and have not had much luck until I found this site. Thank you so much again.

CMcMahon

Calabazas Cyclery. 408-366-2453.

hypersnazz

Beerman beat me to it. Calabazas is the only show in town if you're after BMX.

Oh, and one more tip I just noticed I forgot to add...you can rough up the brake pads a little with medium-grit sandpaper and typically get a little more stick outta them. I thought I stuck that in there, but I guess I didn't.

Maureen

Merry Christmas!

Brian

Maureen, are you getting him a new bike soon? What kind?

CMcMahon

If she goes to Cali, she'll have a wide selection of completes to choose from (including pre-built custom rides, ranging from S&Ms to Standards to Terrible Ones), and a good, knowledgeable staff.

Rob, the co-owner (his parents being the other two-thirds), has been racing BMX since the '80s, and Pat, Cody, Chris, Taylor, and John all ride as well.

Maureen

Yes I am thinking about a new bike, or maybe used. I am thinking about the Redline Micro Mini. It seems like it is slightly big but the brakes would work well for him around our neighborhood. I dont want to go back to petal brakes as he is starting to get the hang of the hand brakes, but right now he cant ride to the end of the street with out running the risk of killing himself. Also, of course it may help him get further around the track. He so desperately wants to go into a race and get a trophy! Do you have kids into BMX?

CMcMahon

Unless I've unknowingly fathered a bastard child, nope.

Brian

I don't. But I raced until a few months ago, and I still help kids at the track, and my neighbour's kids.