[kickstand]

I bought my son an SE wildman, it is "slightly" too big for him, while his 12" walmart bike is way too small for him, he's definitely caught in the middle.

With the handlbars and seat all adjusted for him I the cranks are too long, they put the pedal literally right into the bottom of the seat. from the center of the crank to where the pedal mounts is approximately 5.5" or 140mm.

I'd like to replace them with something like a 4" or 100mm set, this is a one piece crank.

I tried to take the 4" long crank off the other bike, but the diameter of the cranks, is smaller, as is the diameter of the bottom bracket on the walmart bike, so I can't toss them into the SE Wildman bike.

Anyone have any suggestions?

thanks,

CHad

 

[jimmydean]

You can get Sinz in either square or ISIS in 115mm for $50. That's about as short as I've seen. I got some very nice FMF's in 140mm in ebay for $15 and I thought they came as short as 110mm, but I'm not finding any now.

 

[kickstand]

I will check out SINZ, thanks mr. sausage.

It appears the bb diameter is different on his new bike to the old walmart bike, as well as the diameter of the cranks.

I guess I could spend big money and get him a 3 peice crank and modify the crank length myself if it comes to that. I have a buddy that works at a prototype place, I bet he could custom make me some if I cant get ahold of some sinz.

 

[kickstand]

with the SINZ it looks like I have to buy the cranks and a bottom bracket set up? 3 peice only, not a 1 peice?

Not gonna lie, installing the parts I can figure out, but making sure I order the right ones I'm gonna struggle with.

 

[manimal]

i've made several sets of short cranks for noah's bikes over the years...usually in the 100mm range. i lucked out when i moved and now have a retired neighbor that spends his ample free time at his metal shop. he kindly cut and tapped some old 165mm cranks i had lying around down to 110mm-ish for noah's bike. if you can find someone that has access to some metalworking equipment an old set of isis or square taper cranks is the way to go....free is best

i'll check in my garage as i might have a spare set of 120mm square tapers lying around i can hook you up with.

these are about 120-130mm i think...let me know what kind of bb you have on his bike.

 

[kickstand]

i've made several sets of short cranks for noah's bikes over the years...usually in the 100mm range. i lucked out when i moved and now have a retired neighbor that spends his ample free time at his metal shop. he kindly cut and tapped some old 165mm cranks i had lying around down to 110mm-ish for noah's bike. if you can find someone that has access to some metalworking equipment an old set of isis or square taper cranks is the way to go....free is best

i'll check in my garage as i might have a spare set of 120mm square tapers lying around i can hook you up with.

these are about 120-130mm i think...let me know what kind of bb you have on his bike.

metal working tools shouldn't be a problem at all, I have access to mills/lathes/welders/torches/etc.

His bike came with a one peice crankset, I will have to measure the width and diameter of the BB when I get home. I am not sure if I know exactly what measurements to get, but I'll get a few.

 

[jimmydean]

The Wildman came with one piece cranks? I thought it had 3's. I have a set of 175's square taper with Shimano bb I could give you if you wanted to do what Manimal did and cut them down to size. But the bb width would be good to know. Post up a picture.

 

[kickstand]

This is all I have for pics right now, you can see how long the cranks are in proportion to the bike though, wtih one leg fully extended the other is shoved into his butt....poor kid has his moms short legs. I hadn't adjusted the seat at all for him in this picture yet, but I had to drop it nearly all the way down.

 

[kickstand]

The Wildman came with one piece cranks? I thought it had 3's. I have a set of 175's square taper with Shimano bb I could give you if you wanted to do what Manimal did and cut them down to size. But the bb width would be good to know. Post up a picture.

BB width is just under 3" like 2-7/8 or so, or converted loosely to 73mm This is the size of the bike, not the size of the cranks in their currently.

Diameter is approximately 2" or 50 mm

I don't seem to be finding a bottom bracket set up in this size? I am not smrt when it comes to figuring this stuff out, but I need to get these cranks changed so he can ride, the walmart bike is just too damned small.

I tried the local bike shop, but they are not very helpful.

 

[kickstand]

seems 127.5x68 is a fairly common size, where are these measruements coming from and how will I know if this will fit my kid's bike?

 

[manimal]

BB width is just under 3" like 2-7/8 or so, or converted loosely to 73mm This is the size of the bike, not the size of the cranks in their currently.

Diameter is approximately 2" or 50 mm

I don't seem to be finding a bottom bracket set up in this size? I am not smrt when it comes to figuring this stuff out, but I need to get these cranks changed so he can ride, the walmart bike is just too damned small.

I tried the local bike shop, but they are not very helpful.

it should be standard...i installed a bb adapter that allowed me to put a regular splined bb and crankset on my son's 16" haro. i still have some short cranks for a square-taper bb hanging on my peg-board; they're yours if you figure out the bb issue. call the shop in my signature, the owner is mike..he can find the adapter for you.

only pic i could find of the crank/bb setup

 

[kickstand]

it should be standard...i installed a bb adapter that allowed me to put a regular splined bb and crankset on my son's 16" haro. i still have some short cranks for a square-taper bb hanging on my peg-board; they're yours if you figure out the bb issue. call the shop in my signature, the owner is mike..he can find the adapter for you.

only pic i could find of the crank/bb setup

what is standard?

I went to the bike store and asked them if they could order me a bottom bracket for the bike and they said they couldn't. They were less than helpful. I'll call the shop in your sig tomorrow or monday and see fi they can help out.

It really doesn't seem like this should be so difficult?

 

[manimal]

It really doesn't seem like this should be so difficult?

it's not...by standard, i mean that bb shells are usually a standard 73mm width and there is an adapter you can get that converts the bmx style bb shell so that it can accommodate a standard MTB bottom bracket. (bmx bb's are bigger than mtb). just tell mike at cycletherapy that you're looking for the same adapter that "tubby" got for Noah's haro...he'll know exactly what you're talking about
once you get the adapter, you can run any standard MTB bb/crank combo you want.

 

[kickstand]

it's not...by standard, i mean that bb shells are usually a standard 73mm width and there is an adapter you can get that converts the bmx style bb shell so that it can accommodate a standard MTB bottom bracket. (bmx bb's are bigger than mtb). just tell mike at cycletherapy that you're looking for the same adapter that "tubby" got for Noah's haro...he'll know exactly what you're talking about
once you get the adapter, you can run any standard MTB bb/crank combo you want.

Cool, I appreciate your help.

 

[C.P.]

Adapter

 

[manimal]

Adapter

yup..that's it!