# Hey, Need some help assembling my Jump bike, Please.



## Grass hopper (Jun 13, 2012)

Hey forum, I need help assembling my bike, PLEAASE.

I'm a newbie to assembling bikes from scratch, But i'm pretty handy with tools and have ridden bikes my whole life.
So I mainly need help in getting the right parts for my bike frame.
Obviously I need parts that fit, But I'm unsure what parts will fit my bike. So far the job is proving to be a pain in the but,
Because google isn't helping, the local bike shop didn't help either, as soon as they figured out that I wasn't interested in buying their overpriced gear they virtually switched off.

To make matters a tiny bit harder, I live In Poland and I'm not yet %100 literate in the Polish language, and I'm looking to buy the parts on a Polish site similar to ebay.

All help will be TRULY and GREATLY Appreciated (as always)

This is the frame i have. A 13" frame

Da bomb - Grenade










*Bottom Bracket*

Right now I'm stuck on the bottom bracket. Because I don't know what size to get?

I use this site, and the link leads to the bottom brackets listed in order of lowest price first:

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https:// allegro.pl/czesci-suporty-16440?order=p
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This one should fit, right???

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https:// allegro.pl/suport-wklad-deone-127-mm-lozyska-maszynowe-i2368625100.html
```
*rear derailleur*

I also need help with the rear derailleur, As I don't know anything. Actually, I know you can get derailleur's with shorter arms, and since I'm going to use this bike for dirt jumping I think a shorter arm is a good idea, right?

*Gyro brake complications*

I would prefer to get Gyro brakes. Though my bike doesn't have the little stopper things welded on that hold the cables for a gyro, I think it shouldn't be too much of a problem to get around that (hopefully).
But, at this moment I really just want to start riding the bike, so gyro brakes can wait, but, I would like to fit them eventually.

Continued-
At the moment I have a fork Half fitted with a stem, but there is no bolt on top of the fork. I know what I need to buy, except that what I have in mind is not compatible with a gyro brake kit.
I need a bolt (the bolt that goes on top of the fork, above the stem) with a hole through the middle, so that I can run the front brake cable through the fork, But I have no idea what cap to get.


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## L4NE4 (Apr 24, 2007)

I will do my best to help. Is this the frame you have | Buy Online | ChainReactionCycles.com I cant see the picture you posted.

-Bottom bracket- If that link I posted is correct, that frame has a 68mm BB width. What cranks do you have? That will determine what BB you need.

-Read Derailleur- Do you already have a shifter? Are you running one gear in the front? If you have a Shimano shifter you need a shimano derailleur, and same with sram and sram. If you are running a single ring up front you can get a short cage derailleur, if running two rings you should get a medium cage, if running three rings get a long cage.

-Gyro- Just run a longer brake cable. A lot of dirt jumpers run the cable long enough so you can turn the bars completely around without binding up the brake, then on your next jump, turn the bars the other way.


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## jmmUT (Sep 15, 2008)

It's worth having a set of calipers around to measure things, like your BB. You can pick up a cheap pair at any hardware store. 

If you are set on a gyro:
If you are going with cable brakes, you can buy a gyro hanger for your frame but I don't know how well it will work with your brakes, if you are running disc, or V-brakes for that matter. 

If you are running hydraulic disc brakes, there are gyro setups that I don't think require the hangers (I could be wrong) but the hydro gyros have not had the best reviews, although the technology is getting better.

And yes you are right about the stem bolt, if you are running a front brake. What you need is what's called a "Potts Mod" which is just one with a hole through it for the cable which allows the whole front brake assembly to spin with the bars/forks. It will come with the bolt and cap. Cheap and worth having even if you just go with the long rear brake line


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## Grass hopper (Jun 13, 2012)

Sorry I totally forgot to add the measurements. The length of the BB tube is 68mm
and the width is 38mm



ChapmanMTB27 said:


> I will do my best to help. Is this the frame you have | Buy Online | ChainReactionCycles.com I cant see the picture you posted.


Yep that's the one.



ChapmanMTB27 said:


> -Bottom bracket- If that link I posted is correct, that frame has a 68mm BB width. What cranks do you have? That will determine what BB you need.


At the moment the bike is bare. No shifter no crank, all it has is a fork and a stem and soon a stem cap. 
I need to buy a new *crank, bb, chain* (not sure what length chain to get, but If i get the cog wheel in the link posted bellow, Im guessing that will dictate the chain length.)
... *cog wheel* for the front, a *derailleur*, (for the meantime I'm gonna borrow the wheels from my other bike) Also I need handle bars. But ill borrow that as well for now. I'll most probably be able to do the brakes my self, except for the gyro part, well, i might be able to handle the gyro too - and ill have to think about that idea you said, about letting the longer cable just wrap around. (lol)
If you let the brake cable wrap around the bar, doesn't that bend the wire and make it hard to brake? No way id do that with hydro-brakes.
......
The idea was to have a single gear at the front and multiple gears at the back.

Why does the shifter need to match the derailleur? (shifter, as in the thing you put onto the handle bars, used to shift gears?)
I would have thought that any shifter can go on with any derailleur? Because its just a cable that in between.

Ok ok ok. Lets see if I got this right.
Im gonna post some links for a BB, crank, and cog wheel directly bellow. I'm pretty sure they'l all fit together.

*B Bracket*
This BB I think will be a perfect fit, but the axil is 117 mm in length - Iv seen bbs with different length axils and I'm curious as to why they're all different length? how do I know which length axil is right? does it matter?
Suport SHIMANO BB-UN26 BSA imp-rowery (2398343499) - Allegro.pl - Wi

*Crank*
Ramiona korby SHIMANO 175mm M361 (2407068112) - Allegro.pl - Wi

*cog wheel*
Z
or
Blat z

*Short arm derailleurs (link)*

How about this one? to me it looks the best, and is new. (Nowy = New.... Używany = Used)
Przerzutka tylna SHIMANO FT30 krótki wózek,
Question is, will it fit onto the bike?











jmmorath said:


> It's worth having a set of calipers around to measure things, like your BB. You can pick up a cheap pair at any hardware store.


yea true... tools are the bomb. My parents have some old az callipers, but I just used a ruler.



jmmorath said:


> If you are set on a gyro:
> If you are going with cable brakes, you can buy a gyro hanger for your frame but I don't know how well it will work with your brakes, if you are running disc, or V-brakes for that matter.


 I'm most likely gonna get v-brakes.. Cheaper, lighter.. cheaper, plus iv never worked on hydro-brakes and don't have a clue how to. (not keen to learn at this moment)



jmmorath said:


> And yes you are right about the stem bolt, if you are running a front brake. What you need is what's called a "Potts Mod" which is just one with a hole through it for the cable which allows the whole front brake assembly to spin with the bars/forks. It will come with the bolt and cap. Cheap and worth having even if you just go with the long rear brake line


Finally, I found a hollow bolt for the stem. With this it should be easy to sort out the front brake with a vbrake. (Since im using a suspension fork)


Cone bolt with a hole and a star Tioga Links


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## jmmUT (Sep 15, 2008)

I don't know about the derailleur and stuff, as I've always only run singlespeed on all my bikes (DJ and XC) but for your crank stuff, yes it should all work. You want to make sure the bb and crank match for spindle style (these are both square taper so they do) just a warning-square taper is known not to last as long and is prone to stripping. And yeah that tioga stem bolt set up is what you want. You can find a hanger gyro setup-any bmx one should work


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## Grass hopper (Jun 13, 2012)

Thanks man.

Yeh Iv had trouble with the square tapers before, so Iv found the other type with the same sizes and everything and got that instead.

Well, everything is going alright so far. Hopefully Ill get this done in a week. Hopefully*

I was reading some website and apparently you don't even need a stem bolt? Now that I think about it, I remember seeing people riding without them.


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## L4NE4 (Apr 24, 2007)

I am too tired to read that whole post but I got to the shifter and derailleur part. Sram and shimano shifters have a different pull ratio.


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