brainiii

Hello fellow bikers,

got my kid some 18" cheap bike, single speed. Kid complains the bike is difficult to ride the pedals, especially uphill. Kid can ride a bike in general (this is the 3rd bike) so the rider is not the issue. Also got a 20 inch bike which can ride so bike size is also not the issue. What I checked:
1) Tyres have the proper amount of air
2) I calibrated the brakes and they are not rubbing
3) Chain is in good condition and lubed.

The problem seems to be with the hubs. Basically, when u put the bike upside down and spin the wheel, it relatively quickly comes to a stop, unlike my mountain bike and all other bikes.
I don't know if this can be fixed at all? I've tried spraying oil in the hubs but it made no difference, to me it looks they are sealed???

anything that can be done? I can't seem to post pictures as this is a new account.
thanks

Koyote

Remove the wheels and turn the axles by hand. If they feel rough, then they are probably open bearing (i.e., cup and cone) bearings that need adjustment - and they might need more grease, too. Instructions. (You'll need appropriately-sized cone wrenches.)

Iride01 

Is this a kids bike with or without multiple gears on the rear?

I've never looked at the actual ratios on the kids bikes, but at a glance, many kids bikes don't really have the gears for climbing with out it being very hard to pedal.

But maybe your kids bike and my idea of a kids bike aren't the same. So it'd help to know what bike this is....... even if it were a adult bike that would help greatly.

pdlamb

If Koyote's bearing suggestion doesn't work, have you checked the tire pressure?

Koyote

OP states that the bike is a SS and the tire pressure has been checked. States that the problem is "Basically, when u put the bike upside down and spin the wheel, it relatively quickly comes to a stop,"

I doubt that this issue would make a bike feel noticeably sluggish, but the OP asked about the hubs...Hence my suggestion.

Iride01 

Missed the part about being a single speed.

Not sure why you feel you have to defend your suggestion. I didn't have any issue with that.

Though being a single speed bike, it will be much harder to go up hills as the child reported. And if the child isn't use to that particular gear ratio because their previous bike was an easier ratio, then their initial gripe will be that it's harder to pedal.

Koyote

No, not really defending my suggestion. I thought your comment about the gearing might be the real issue, and that had not occurred to me -- so was explaining why I gave the advice about hubs.

cxwrench

There's your answer. Is it a coaster brake? They don't spin well either.

DiabloScott

One more idea - I've seen kids' single speeds that were built with the chain too tight - since the cranks aren't usually high quality they're sometimes out of round so the chain tension is fine at one spot, and tight enough to bind 90° later.

But why are you turning it upside down to spin the wheel? Just pick up the front or back end and give a little spin.

TPL

Adjust your hub axles

GamblerGORD53

Bearings are likely poorly lubed and tight. Common on ANY new bike or gotten used.
My old CCM front wheel will spin 3 or 4 minutes. Same with both my SA drum brake IGHs. My roller brake wheels both stop in 25 to 35 secs.

One day last year I was at a convenience store when a teen came in with a BMX bike and set it upsidedown. As a lark, I gave the front wheel a little spin and it wouldn't quit before he went back to it. LOL.

I bought a new bike this year for $1,000, so not cheap. It came with roller brakes and Nexus 7i.
I sooner or later figured out that ALL the bearings were tight. I took apart the pedals right away, because they wouldn't spin even one whole rev. WTF.

JoeTBM 

Many fine suggestions here but one I didn't see and recommend that to check if the chain from the crank to the rear wheel is too tight and causing binding. We have seen that on a lot of children's bikes lately from Chinese manufacturers

dabac

My money would be on the gearing ratio.
wheel bearings have to be VERY poor before they become an obvious obstacle.
How a wheel spins unloaded doesn’t give a good indication of how much they contribute to the overall drag during riding.
2nd guess would be chain binding.
3rd would be crank arm length.
Cheap kids bikes can come with just about anything, even ”adult” crank lengths. A kid might not have the vocabulary to explain why that feels wrong.

brainiii

1) chain is not too tight, it's just right so that it doesn't fall off the chain ring (which did happen a couple of times before i adjusted it)
2) I find that upside down is so much easier to check and compare front and rear wheel spin and generally "work" on the bike

brainiii

I should add here that the bike has normal v brakes (someone asked about coaster brakes) and that one noticeable difference from the previous, smaller 16" bike is that this one is heavier, so naturally it was gonna be harder to pedal compared to the previous one.
However, I just wanna see if the riding experience can be improved, hence the slow wheel spinning question.

Thank you all for the suggestions. I would like to try to open up the bearings and relube them but have no idea on how to or even if they can be opened. I wish I could post a picture.

Moe Zhoost

This is what you need to do first. Having worked on dozens of cheap kid's bikes this past year, I've found almost all of them with wheel bearings that were too tight.

Iride01 

You can.

You just can't do it in a post here yet. But you can put the pic on a hosting site and then in the plain text of your next message, write the URL of the sharing link to the pic. Remove/delete https:// from it and then put a space on either side of any . in it.

Someone here will know how to fix it and will post your pics for you. imgur.com works real well for this, but others too work if you insure you get the link to share with other non-members of that site if they require a membership.

Don't use any of the linking tools in the editor. There is a gallery here on BF you can use too, but in the past it's still taken some time for pics from noobs to show up. You could go out and participate in other conversation here on BF. After you get past 10 total posts your restrictions for image posting drop away. Don't try to do that in the same day though. As a noob there are daily limits for posting or some such thing.

It's all for helping with spam on the site. Unfortunately it's impact affects noobs with no intention of spamming.

JoeTBM 

Sorry, I missed your replied about a too tight chain

brainiii

ok, here are the pics of the bike.

ibb.co/rfkTsKh
ibb.co/xY572VB

add https in front

JoeTBM 

Well the chain doesn't look too tight but the chain looks dry, could use a little oil there but I see you said it was lubed in the OP

So without being able to put my hands on the bike, I go along with a slight cone adjustment of both wheels

Iride01 

Here we go...


https://ibb.co/rfkTsKh

https://ibb.co/xY572VB

Iride01 

It could be the bearings too tight, but still that look to be a big chain ring for a children's bike. Which means it'll be harder to pedal than any children's bike with a smaller chain ring.

Is that 34 teeth or better on the front and only 14 on the back?

Russ Roth

You've already said the wheels don't spin freely, pull the wheels off and adjust the hubs till they do. You'll need 2 sets of cone wrenches ideally, 13mm in the front and 15mm in the back. Adjust the cones outward till the wheel spins smoothly, check the bottom bracket for the same, that can often be tight as well. All those will effect the ease of pedaling. I doubt the gearing is much of an issue, plenty of kids run around on the factory gearing without ever changing it and do fine but if the wheels are tight and the BB is tight, that's all just excess resistance.

UniChris

Would agree the wheel bearings should be adjusted right.

In terms of gearing that model doesn't appear to be on the vendors site and they don't say what's upfront but it looks like they're using 18T in the back on most of their kids bikes.

Looking at some others I'm seeing a specialized that's 26:16 on a 16" wheel for 26 gear inches or 36:18 on a 20 for 40 gear inches

Single speed kids bikes are made for driveways, parking lots, and rail trails more than climbs, but those aren't crazy ratios for climbing moderate things.

Another biggie with kids bikes is the seat often being set too low as that gives more confidence - but it may have to come up only a little bit at time, possibly a small measured step after bedtime, and another a week later. When they start doing the whole pedal out of saddle then sit down and coast routine, adjustment is needed.

DiabloScott

Exactly - the kid's complaint that riding is hard is not useful. The OP's statement that the wheels don't spin freely IS. He didn't say if the front or back is a bigger problem or both the same, but big gears don't stop wheels. If the wheel doesn't spin well when it's off the bike, it's a hub/lube issue. If it does, but it doesn't spin well ON the bike, it's an alignment or truing issue.