Qmavam

Short of it. Wife picked up junk bike someone threw out, wants me to fix it for son-in-law.

Please note, I'm not assuming any quality here, she just wants to give him a bike to ride with his son.

It is a GT Agreessor Pro, Chinese made bike. It has a Shimano Acera derailer missing

the top small sprocket. The other one has 13 teeth.

I'm not knowledgeable about bikes but handy enough to do a replacement. If I had the sprocket and bolt,

I'd install that. Are those parts sold separately?

If I found another junk bike with a Shimano 13 T derailer any reason that wouldn't work.

If not, are derailers standard? Meaning, can I just order any derailer from Ebay or Amazon and it would fit?

Can I assume the GT Agreessor Chain is Standard?
EDIT to add,
This is a part I'm thinking about ordering, (if I need to order), I picked it because it has 13 T others don't.
Ah, need to give Ebay description, I don't have enough posts for to post URLs.
So here is an Ebay search term that brings up the derailer
SHIMANO RD-M360-SGS ACERA 7/8 SPEED BLACK DIRECT MOUNT REAR DERAILLEUR-NO PACKAG


Thanks for any enlightenment you can add, Mikek

ddeand 

Like this?
https://www.ebay.com/itm/Road-Bicycl...aLv3Gwm09wu1uQ

dedhed

Any long cage shimano derailleur from the 6-9 speed era will index correctly with the shifters.
Plan on replacing the cables (inner & housing) and likely flushing old, hard grease out of the shifters with WD40.
Yes you can replace the pulley, but it needs to be a "G" pulley that has some side to side movement to allow smooth running. Bolt might be harder to find if it's missing.
The one you linked is fine.
Another Shimano from a junk bike would work (correct mount, cage length) 11T - 13t really doesn't matter.

If you have a bike coop nearby you can probably buy a good used one for cheap.

Any 6/7/8 speed chain is fine KMC, SRAM etc.

hokiefyd 

Yes -- the RD-M360 is the exact derailleur, but any derailler that advertises compatibility with 6/7/8/9 speeds will work. It's definitely a bike worth making right again. They were and are sold by Dick's Sporting Goods and are decent entry level MTBs. They have a freehub rear wheel (vs. freewheel) and disc brakes that could be upgraded to any type of hydraulic brake. Get it running, and it can grow and evolve with the rider's desire and skill level.

Qmavam

Thanks all,
I ordered the sprocket, hopefully I'll find a bolt locally that I can make work.
If it doesn't work after that, I'll order the whole unit.
Mikek

JoeTBM 

I hope you are not in a rush, that part is coming from china.

PM me your address and I'll send you a bolt that should work

HillRider

You need the correct bolt. OEM bolts are "shoulder bolts" meaning they are threaded only part way so they screw in a specific distance and then stop thus maintaining the correct gap for the pulley to fit in. The threading is M5x0.8.

Andrew R Stewart 

If the OP is talking about a der pulley bolt then they are not shoulder bolts at all but have a smooth shaft where the pulley will be located. The pulley has a sleeve/bushing that gets trapped by the bolt and the pulley freely rotates on that sleeve/bushing. The bolt could be any one of the correct length and threading and doesn't need any "shoulder" aspect to work.

Now if the OP is meaning some other bolt... we can't say much from the lacking description. The OP might be meaning the der hanger mounting bolt, which is a "shoulder" type but typically having 10x1 threads. Or the OP might be meaning the der mounting plate's (poorly called a "claw" by some) nut and bolt that keeps the plate attached to the drop out slot, these bolts could be a M5 thread but don't use a "shoulder" design. Andy

JoeTBM 

I presumed that since he was ordering a missing sprocket (pulley) that it was that bolt, I have several spares that I salvaged off old (bad) ders from donated bikes.

HillRider

Yeah, I misinterpreted the design. The bolts do have a smooth, unthreaded shank but the spacing is indeed defined by the bushing.

Qmavam

I appreciate that! It sounds like it's a bit specialized, so I will take you up on the offer.
I see the sprocket comes with two bushings that look to be different ID, so I think we're covered on that.
I'm a newbie without enough posts to PM. :-)


Thanks, Mikek

Qmavam

Someone sent me a PM.
I am unable to retrieve it because I don't have 10 posts, and the software won't allow me to look.
You can send me an email at lamontcranton17@yahoo.com

Thanks, Mikek

JoeTBM 

It was me that sent the PM but your email can't be sent, got an "Address not found" error and I used copy|paste to retrieve it.

Try my email

JoeTheBikeManFlagler@gmail.com

Qmavam

Hi guys,

I have a new development, I've never seen this style Shrader? Valve. How do I put air in the tires?
Is there an adapter?
Ah! I can't post the image, I'm not up to 10 posts.

Thanks, Mikek

Qmavam

Hi guys,
I wanted to air the tires and found a non standard Schrader Valve.
How do I use that?
Is there an adapter?
I can't post images, but you probably know what I have, but maybe the moderator will let my link in,
but I have to get past the software, so try this.

Add that HT... and 3 W thing to the front,

dropbox.com/s/psfq39b4v181ld5/

and put this on as the last half of the link.

schrader%20valve%20not.jpg?dl=0

To see an image of the valves.
Thanks, Mikek.

Unca_Sam

If it's not a schrader, it's a presta valve. There are adaptors to use a car tire compressor for it, and many bicycle pumps will fit it.

mpetry912 

Your bike shop will have a "presta valve adapter", it will cost a buck or two.

Get a couple, they do get lost.


Mark Petry
Bainbridge Island, WA USA

Qmavam

Thanks,
"It's always something"

JoeTBM 

+1 Presta valve, just need an adapter Some bicycle pumps have them built into the head (reverse the fitting) or the adapter is attached to the pump lever.

https://www.ebay.com/itm/10pcs-Prest...4f39762f50bd82

JoeTBM 

Did you get the parts we mailed to you?

Did it fit?

Qmavam

Sorry Joe, I haven't attempted repair yet, I'm still waiting for a couple of other parts that needed replacement,
and I have delivered the bike to my son-in-law. I won't be able to finish until I return to their home again.

JoeTBM 

@Qmavam - a big shout out to you.

You are a stand-up guy. I truly hope the part I sent you helped you and was were able to resolve the issue with the rear DER.

Thank you for the donation to my shop, it is really appreciated.

The Bike Men of Flagler County
JoeTheBikeManFlager@gmail.com