bvachon29

Hi all,

I've done a lot of searching around here with some limited success. I recently acquired my Dad's '84 or '85 Mongoose ATB. All chrome, in decent shape, just was sitting around. I'm planning on making it into a city cruiser type so looking to upgrade a few parts.

Problem is finding things for this bike. The stem I've found to be 21.1mm quill or .833(?)". Found a few on eBay but is there a source for these new? Secondly is the seatpost. I'm in need of something longer but I am having a hard time determining the seatpost size. I've read somewhere that its a 25.7mm. With the calipers, the seatpost ranges from 25.5 to 26.2 depending on where the post is measured. I'm guessing it's just worn down after the years?

After that I think it just needs a good tune-up, new brakes and tires and it should be good to go. Any suggestions for good replacement cantilever brake pads? Sorry for the rambling post, I'll try to post up some pictures soon.

eeuuugh

I love those old Mongoose ATBs! A very "cadillac" ride.

the original bars would have been "bullmoose" bars, something like this: https://www.ebay.com/itm/Vintage-Bul...m/124211392019 this was the only one I saw on ebay in 30 seconds of searching, but they are often available, especially in bike co-ops. 21.1 millimeter stems are still available, often sold as BMX stems. Low end kids' BMX bikes are the only modern bikes I know of that still come with that size quill. BMX stems usually have removable faceplates and only take bars with a 22.2mm clamp diameter, but I know J&B also sells a 21.1mm "ATB" stem with a more common 25.4mm clamp diameter. Any bike shop should be able to order this. Early-mid 70s Schwinn, Raleigh, and some Japanese brand 10 speeds used 21.1mm quills as well, often marked .833", with a 25.4mm clamp diameter. Here's an example: https://www.ebay.com/itm/SR-21-1mm-8...4/283904586830

For brake pads, get Kool-Stop eagle claw II pads with a threadless post. By far the best.

Good luck on the seatpost! I would take the bike in to a bike shop and have them figure out what you need. If they get it wrong, at least they'll be on the hook for it

wesmamyke

Can't say for certain, but some early Mongoose bikes do have odd seatpost sizes. My Californian BMX had a 22.6mm, when almost all BMX bikes had 22.2mm at the time.

bvachon29

Thanks for the info on the parts! And yes, its the all Chrome ATB. Was too cool to let my Dad get rid of!

bvachon29

Also, for my sake will more than likely just take it to a bike shop to have them determine the seat post diameter. Thanks again for the help,

bvachon29

Tried to upload some pictures of the bike but apparently I need at least 10 posts before I can do that

madpogue 

CLEAN the seatpost thoroughly, then get an LED forehead lamp and a magnifying glass, and go looking for a diameter marking. It should be below the minimum insertion line or hash marks.

Photo assist:


Appears to have a "slingshot" stem, similar in appearance to a combined "bullmoose" bar/stem, but bar and stem are separate. Whatever you do, save all the original parts, as they're a major factor in the value of a bike like this.

bvachon29

Appreciate the info. I was planning on keeping everything. The post is pretty oxidized so I'll give it a good clean and see what I can find. I appreciate the insight.

stardognine

Nice bike, but I think they were still called ATBs back then, as in All Terrain Bicycle. That’s what they called my ‘86 Schwinn High Sierra, in the catalog. ATBs are far cooler than MTBs. 😎🤔😁

madpogue 

^^^^^ +1, and the 700C'er were called "cross" bikes rather than "hybrid". Definitely higher cool factor in both cases.

So that seat post looks like it might be an SR Laprade. Does it say LAPRADE up on the top section, right side?

stardognine

Funny you should mention that. I have a similar one, just branded Sakae, rather than SR (Sakae-Ringyo). I’ve been meaning to ask about it, but keep forgetting. 🤔

madpogue 

^^^^^^ The more generic Sakae seat posts usually arent fluted like the SR Laprade. The top portion has a little bit different design, too.

tricky 

Side note, but how do you find the user's gallery? I can't seem to find a way to search in the forum UI.

tricky 

bvachon29 I used to have one of these but I received it as frame only. Do you have the rims that have holes in them that show the rim strip? Those are such a cool unique feature of the stock build of this bike. Also, I seem to remember this bike having the cantis with the spring anchor hole on the outside of the canti posts. Those are unique to this bike as well. I seem to also remember the rack braze-ons having a non-standard (i.e. non M5) threading. Lots of quirks but I love these bikes,

madpogue 

Float your mouse over a member's name, and you'll see a URL with the name, a hyphen, and a number, 4 to 6 digits. For example, the number associated with you is 41692. Then you just key in a url with that number -- example -- https://www.bikeforums.net/g/user/41691 .There's probably a (pun slightly intended) trickier way to do it, but as a typist from way back, this works for me.

The Golden Boy 

"Vintage ATB Standards."

Heh.

beicster 

I had the red version of that bike. It made a great commuter. Make sure you keep those brakes. They are difficult to replace with the spring hole on the outside.

stardognine

I concur, sir! 😁 Here’s mine, aquired just last week, along with a lot of the better Suntour stuff. That parts bike was exactly the same bike as I’m riding, but it was an ‘85 instead of ‘86, if I read the serial number & headbadges right, and a little worse, on paint. They even had the exact same paint & decals, lol, just a different mix of parts.

I

stardognine

My High Sierra also has an off size for the low-riders’ mounting bolts. If normal is M5, these are more like M6 or M6.5, possibly even M7. It’s really lucky for me, that I grabbed the old ones from that parts bike, because I lost one yesterday, and my pannier was flopping around for a bit. 🙄 I’ll definitely be grabbing some lock-washers today.😁 😉

bvachon29

Well thank you everyone for the help here. Who would've thought that the seat post diameter was on the post. 'doh! Anyway, just looking to get a longer one so the bike fits me better. Next step is going to be taking it apart and cleaning and re-greasing things to get it running.

I'm sure there's many posts for this which I will search but any best way to tackle cleaning the chrome? The bike is not perfect and has some pitting but just looking to restore some of that 80's chrome bling!

bvachon29

Anyway the post was 25.8mm. Found one online as a replacement. Once I can post up pictures on here I'll do a dump.

bvachon29

Well, it's been a hot minute, but finally got it all buttoned up.

Het Volk

Just an amazing bike.

The Golden Boy 

Gotta love chrome bikes!!! Beautiful!

1simplexnut

that scrubbed up well !
I see you have the pro rims with the holes . Nice !