I'm jealous of all yas swifty bags and racks that hold more racks and stuff, and tired of going "bike camping" while carrying a full backpacking pack, it hurts and is bad. So with the emotional prodding of Rza, I am building myself a camping bike. But because I am me, I am ignoring the idea of buying a bike that is designed for that. No no, instead I found a rad small run early 90s Ti 26" mountain bike frame that is really really hard to find info on, and I'm going to build it with that.
But now I'm hoping for your help and bike nerdry to help me in my foolish moves.
I'm shooting for a build level somewhere between 'shitty riding quality' and 'getting a fork custom made for me'.
Here is the frame.
It's a 1992(?) Titan (of bmx fame) Titanium Compe. It currently has no fork (relatively simple) and no bottom bracket (horrible). Those are steps no1 to accomplish.
1) Fork advice. I want to run a porteur rack day to day + a lowrider F rack/paniers and buttrocket for trips. No rear rack if I can avoid it. Fork needs to be:
-26" wheel
-eyelets everywhere
-non suspension corrected
-1-1/8 steerer (headtube is actually 1-1/4 but I'm going to go with 1-1/8 headset and reducers for "simplicity")
-don't care about brake type - mullets are hip again.
-would love to run rat trap pass tires but could go smaller if needed
So far the Surly LHT fork makes sense, but is somewhat aesthetically unpleasing to me with this frame. Also looking at Surly Troll un corrected fork (adequately rugged, but acceptable offset to happily run lowrider bags?), Salsa Vaya (probably un-ideal tire clearance, trail?), Thorn option (???), or maybe something like begging Rawland for a Ravn fork ($$$ if even possible) or something along those lines.
Okay, those are the options I've found. Notably, again, I don't know anything about cargo on bikes. I'm googling furiously, but you actually have experience. Hence asking you advice.
A) Is there a best option there, according to potential ride quality? That is the #1 priority. Headtube angle is a piece of information I do not have, and am not sure how to get, so it's guesstimation.
B) Are there other, better options you guys know about?
2) Need a bottom bracket. This is the reason the guy sold me the frame, I'm sure, because he didn't want to deal with it. It's... un ideal. 63mm bb shell width, with 39mm ID press fit. This adheres to NO standards that I can find any information about anywhere, so Titan appears to just have been making it up as they went along. Again, they were a bmx company primarily, but I can't seem to line this up with any old BMX standards, either. And I haven't yet been able to find any bearings of any type, bike or otherwise, that have a 39mm OD, although I haven't entirely done diligence on that yet - they've got to exist, right.
Does any of this ring any bells for anyone?
I'm wondering if it's going to come down to having some pressfit cups made that can take available bearings and then going from there.
Other possibilities:
-Spanish standard bmx bearings have an OD of 37mm, with some sort of machined press in spacer I might be able to use those.
-There's a modern pressfit standard, BB86, that has cups with an OD of 41mm. Which is close, and could potentially be shaved down to fit, if there's a lot of extra material and I don't mind maybe dying if/when it fails.
-the old Klein standard pressfit bb has an OD of 35, too small, would need cups made.
I'm hoping to throw this at Colin soon if things need makin', but thought I'd air it here, first, in case you lot have any good ideas.
Flex your big knowledges. Thanx for the halp.
"Fast" Zack H
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langston
Posted: Fri Jan 27, 2017 5:19 pm
Joined: 25 Jul 2005Posts: 5547Location: Columbia City
Jesus, Zach. Why not just go with a vintage French frame if you wanted to make life hard? Gotta double down on the esotericism huh? Here's a gold star!
Seriously though, that's a pretty cool looking frame and I bet it will be sweet once Fred comes in and saves the day.
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zackh
Posted: Fri Jan 27, 2017 5:41 pm
Joined: 26 Jun 2014Posts: 28Location: burlurld
something something Made in Amurica something.
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walker
Posted: Fri Jan 27, 2017 6:32 pm
Joined: 05 Aug 2015Posts: 1855Location: beastcake
maybe email problem solvers? doubt they have something to sell you, but they might be able to point you in the right direction.
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donavanm
Posted: Fri Jan 27, 2017 8:24 pm
Joined: 14 Jun 2012Posts: 1342
Doooomed. Seriously this frame looks like a time and money pit that may or may not turn out usable. That said:
Head Angle: This, along with ST angle and BB drop, depends on fork + wheels used. A longer fork will slacken the head angle, shorter fork will make it steeper.
Once you have a fork and a flat surface you can experimentally find the HT angle. Or get out a tape measure and calipers and play around in BikeCAD to guesstimate. Youll probably want a 71-72 HT angle.
Fork: Any idea if the frame was "suspension corrected" or not? I think '92 could go either way, but probably used 60-80mm of travel. I'd guess it does based on super short HT. Depending on original geometry the fork was meant to be in the neighborhood of 400-415mm Axle to crown, with ~40-45mm of rake. I think. If you're using disc brakes ignore "wheel size" and just look at Axle To Crown plus width/tire clearance. EN ratings mandate 6mm of clearance on either side of the tire, ie a 52mm inside width would work for a ~40mm tire. Add/subtract a centimeter or so for fenders. Find a suitable steel disc fork on ebay/bikeworks/recycled. Have someone add rack/fender brazeons. Rattle can it.
BB: Youre fucked. Modern "two piece" cranks with integrated axle/external bearings are all designed for 68mm ("road") or 73mm ("mtb") shell width. Classic cartridge square taper units are the same. *maybe* you could find a wierdo axle of the right width and use cicra 70-80s loose balls and independent cups/races. Or, as mentioned, get someone to machine you spacers. Maybe something like a press fit/bonded spacer that was 68/73 wide with 1.375x24tpi "english" threads (35mm ID) to imitate a "standard" shell you could use screw in bearings of choice?
PS: whats the TT/ST/CS length? Because of the MTB heritage you might be excluding drop bars as a sensible cockpit.
PPS: Whats the rear protrusion on wishbone?
PPPS: Have you started scoping out seat posts yet, that can get wonky too.
Edit: besides Axle to Crown for geometry you also need to know axle to lower crown clearance for tire fit. For an approximation add half of Bead Seat Diameter (BSD), Tire Width (roughly the diameter, and 1CM of space to clear mud etc. For a 26" wheel with RTPs thats 559MM /2 = 279.5 + 54mm + 10mm = 343.5mm from the axle line to the lower/inner crown. Any sort of suspension corrected MTB fork should clear that.
Edit 2: Oh yeah, since this is a weirdo early 90s mtb maybe hit up ducttape on these forums?
zackh
Posted: Fri Jan 27, 2017 9:23 pm
Joined: 26 Jun 2014Posts: 28Location: burlurld
Re: BB. What do you think about a pair of spacers/cups that are 39mm OD, 35 ID with standard threads, that are 15.5 mm length each (that's the 13mm present within the shell from the inner press fit lip to outer edge of shell, plus an extra 2.5 each side to make it out to 68). Pressed in to each side they reduce the diameter to usable standards, provide threads, and extend the shell length to necessary 68.
Wait. I just reread your post and that's basically what you were talking about, yeah?
Or. I found a photo from an old ebay sale of one of these, that had a mavic bb in a box included in the sale. I don't speak german so I can't 100% tell the two things are supposed to go together, but it's a pretty good assumption. So maybe that's the avenue to explore. Seen here. Scroll on down through the photos and you'll see it.
Re: the other stuff.
HT angle/tires/arglebargle - really, at present that's a concern only for informing which fork to get. So I think it's probably more of a "just get a best guess fork, see how it rides, then replace if needed" situation. i don't love it, but I'll do it.
Fork: not suspension corrected, this was a full rigid jam.
PS: seriously, I'm building this bike like a psycho. Upright stem and VO crazy bars if I get my wish. I have a picture in my head, and I'm going for it, 110%.
PPS: Wishbone is approx 115mm from center of seattube to center of the cylander that's connecting the wishbone to the loop stays, or about 90mm inner edge to edge. That said, it's a little curved, so that's not a perfect measurement.
PPSP: That is mercifully normal enough, 26.8
edit: the photo I mentioned shows the mavic bottom bracket... and a pair of cups, I think. Or maybe they're headset spacers.
edit^2: looking back at the retrobike thread photos, here, that ain't the Mavic BB. Something freaky going on though... the protruding bearings (?) makes me think the mavic BB is the right style, the shorter shell with bearings ticking out from either end.
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jimmythefly
Posted: Sat Jan 28, 2017 5:37 pm
Joined: 10 Jan 2007Posts: 1491
Looks like this guy solved the problem with a YST bb + custom cups.
There are references online that say the MCS Mantis used the same BB as the Titan. CAUTION! There are also references that say the MCS minis and the Titan Minis used a press-in with circlip type BB, but note that is different than yours that is press-in cups with no circlip.
With that in mind, might want to contact these guys for actual measurements:
Have Colin turn that down on the lathe to be a pressfit for your shell with a 2.5mm raised lip on one side, and bond it in with Loctite 609 Retaining Compound.
For the fork selection you should start with a random partsbin find to get the bike rideable and take measurements from to dial in further, the angles get determined by the fork dimensions and vice-versa so just start "somewhere".
Have Colin turn that down on the lathe to be a pressfit for your shell with a 2.5mm raised lip on one side, and bond it in with Loctite 609 Retaining Compound.
I'm not sure that's actually going to work the way you're thinking since the wall thickness on that bottom bracket shell inside the area bored for bearings is really thick.
Zack says the lip from the bearing area to the center section of the shell is 2-3mm, which means we're looking at an ID of ~34mm in the center section. ISO bb thread is 1.37" (34.8mm), so assuming the adapter is that ID straight across, if I tried to turn it down to fit, I think I'd turn away the center section completely and be left with two separate end pieces. I guess that could actually still work. If I'm going to make adapters, I might as well start with a $9 part and save me the trouble of cutting bb threads.
jimmythefly
Posted: Sun Jan 29, 2017 12:31 pm
Joined: 10 Jan 2007Posts: 1491
RE: Fork.
Check Recycled Cycles. Last time I was there they had a Kona P2, 1-1/8" steerer, with lowrider bosses and double eyelets at the dropout. Disc brake only. It was in the neighborhood of non-sus corrected for 26".
I myself have a Kona P2, non-sus corrected, disc only. But mine only has single eyelets at the dropout. $50 if you woudl like to purchase.
dashap
Posted: Sun Jan 29, 2017 1:09 pm
professorJoined: 21 Jun 2006Posts: 1565Location: central district
Those dropouts scare me.
zackh
Posted: Sun Jan 29, 2017 4:03 pm
Joined: 26 Jun 2014Posts: 28Location: burlurld
Just swung by recycled, the P2 was gone (or I didn't find it anyway) but I did end up with an anonymous 26" fork that'll be perfectly fine to get started with.
I've also remeasured the BB shell. Confirmed 39 mm ID, with a 2mm lip at about 13mm inside, bringing the middle ID down to 35 (there's also a small screw sticking up in the middle that's holding the bottom of the bb plastic cable guide on, but I'm sure that could be glued).
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jimmythefly
Posted: Sun Jan 29, 2017 5:50 pm
Joined: 10 Jan 2007Posts: 1491
I might have an even better fork for you to try.
It's a GT "2x4" fork. It has adjustable offset to 3 different positions.
Looks just like this, only used:
1-1/8" threaded steerer.
Unfortunately I do not know the actual offset dimensions, I will try to measure it. A quick google was not fruitful.
You are welcome to borrow it, or purchase. If you borrow it I'll need you to keep it threaded and not touch the steerer length (you can borrow the headset with it).
If you want to buy it, let me know how much steerer you need, might be able to cut the top off and use it threadless.
blasdelf
Posted: Mon Jan 30, 2017 12:35 am
BAD NAVIGATORJoined: 01 Mar 2010Posts: 1505
holy crap Jimmy comes through with the ideal fork for this project
even worth it if you have to use it threaded for testing
or a silly deal where the threads don't go down all the way but there's not enough to clamp to either, so you use a threadless headset with a stack of spacers and a threaded locknut on top
(Tommy's got the odd oversized quill-to-threadless adapter you might want for either of those scenarios)
blasdelf
Posted: Mon Jan 30, 2017 12:38 am
BAD NAVIGATORJoined: 01 Mar 2010Posts: 1505
dashap wrote:
Those dropouts scare me.
that design is called a "looptail"
it's strong enough for a few prominent MTB and BMX companies to use it as their trademark aesthetic for decades
zackh
Posted: Mon Jan 30, 2017 8:49 am
Joined: 26 Jun 2014Posts: 28Location: burlurld
Oh, that fork is too right. Definitely would love to give it a try, with an eye to buy. I think my headtube is 83mm short- I measured it this morning but forgot to write it down, so that's approx. I don't have a headset yet, so I can tailor that to the fork ifn's that's how I want to go.
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zackh
Posted: Mon Jan 30, 2017 8:57 am
Joined: 26 Jun 2014Posts: 28Location: burlurld
Also, Fred- the WTB rims you were talking about yesterday - looks like they came in at least an "XC" (maybe 25mm wide?) and "Freeride" 28(again, maybe?)mm wide variant. I imagine with fat slicks you'd advocate the wider rim for ride quality?
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blasdelf
Posted: Mon Jan 30, 2017 12:48 pm
BAD NAVIGATORJoined: 01 Mar 2010Posts: 1505
aww damnit WTB discontinued all their rim brake products again, probably for the last time
funny enough, after you went back into the bikeworks warehouse yesterday I found a Dual Duty FR wheelset, but they were built up with hyperbeef hubs for now-obsolete DH standards
Modern tubeless-able 26" rims with a brake track are rare eggs now
I'll send you some weirder vintage stuff separately
axel
Posted: Mon Jan 30, 2017 1:10 pm
Joined: 15 Feb 2013Posts: 1654Location: St Johns PDX
blasdelf wrote:
aww damnit WTB discontinued all their rim brake products again, probably for the last time
wow, looks like it - even the 700c ChrisCross rim isn't on their site anyone.
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walker
Posted: Sat Feb 18, 2017 4:56 pm
Joined: 05 Aug 2015Posts: 1855Location: beastcake
zackh wrote:
bb fuckery
sheldon's site just got a bb crib sheet update. I don't think there's anything there that will be an instant solve, but there are a couple interesting links:
Code:
Phil Wood may solve your problems: "[i]f you have a press fit bottom bracket (Merlin, Klein, Fisher, Ritchey, Fat Chance) and need replacement parts, we have spindles and bearings that will work" -- see Phil Wood FAQ page on bottom brackets. Wheels Manufacturing makes a number of adapters between these systems, and FSA makes some. Also see compatibility information in the table below . -- John Allen.
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