Has anyone made a trike out of a Sears Flightliner/Spaceliner bike?

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Well, ever since I chose to put a hold on selling/trading my stash of unused bike stuff, I've decided to have fun with the stuff I previously had no interest in. I already took the bent up Hawthorne frame I had planned to get rid of and turned it into a keeper, but now I'm debating on what to do about the bike I instantly regretted buying moments after I got it. Personally, I don't have much interest in girls' bikes, but when I removed the sticker from the seat pole and saw that beautiful purple paint hiding underneath, well, let's just say my interest had been piqued, especially after I learned it matches the paint on my Sweet 16 Redline Hot Wheels Custom Eldorado!

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Here's the rub: I want to first use this bike to learn how to do an oxalic acid bath, but after that, I want to sandblast this bike, powder coat it as closely to the original color as possible, and customize it to match my Hot Wheels Eldorado, redline tires included. Thing is, I kind of want to convert it to a trike, as I don't have a trike at this time, and to have one in purple would be really cool. I just don't see many people turning Sears Spaceliners/Flightliners into trikes. Is there any reason for that? Would it still be possible to convert this bike into a trike, possibly with fat tires in the rear?
 
I have no personal experience, but I have to think that whatever mechanical magic is used to create a trike is applicable to that frame. I note that you plan to use oxalic acid followed by abrasive blasting. I can't think of any advantage to the oxalic acid in this case. Just blast it!
Have fun!
 
There's no reason it can't be a trike, girls frames get used for trike build a lot.
I remember someone building one with a spaceliner and a TRM tank, but don't remember who.

If you don't want to weld to the frame, you can buy bolt on trike kits. Though I'm not sure how wide a wheel/tire combo you can put on those.

I built my first trike here with the rear end of an old industrial trike, it bolted to the frame it was on so modification was minimal.

Edit:
Here's a shot of the one I mentioned.
You can see where I cut out slots on the rear end for the seat stays to go into, then just bolted the dropouts in place.
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I have no personal experience, but I have to think that whatever mechanical magic is used to create a trike is applicable to that frame. I note that you plan to use oxalic acid followed by abrasive blasting. I can't think of any advantage to the oxalic acid in this case. Just blast it!
Have fun!
I want to try an oxalic acid bath on this bike as I'd never done it before, and I'd rather mess up on this bike than mess up on the other bikes I'd like to try this on. Plus, if I mess up on this frame, it won't be an issue, as I plan to strip it down anyway.
 
There's no reason it can't be a trike, girls frames get used for trike build a lot.
I remember someone building one with a spaceliner and a TRM tank, but don't remember who.

If you don't want to weld to the frame, you can buy bolt on trike kits. Though I'm not sure how wide a wheel/tire combo you can put on those.

I built my first trike here with the rear end of an old industrial trike, it bolted to the frame it was on so modification was minimal.

Edit:
Here's a shot of the one I mentioned.
You can see where I cut out slots on the rear end for the seat stays to go into, then just bolted the dropouts in place.View attachment 139048
I'll have to do some digging for that particular bike then. I've only seen one other Space/Flightliner trike, but it had some bars welded to it to make it look more like a men's trike.

I was thinking I'd use a bolt-on kit, but I'm open to trying whatever for this frame to look and function the way I'd like. I know that there's a way to put fat tires on these kits, but it may be too expensive. What would be really cool is if I could put some old school Cragars with redline cheater slicks on the rear axle. It'd probably be a bit tough to pedal, but it'd help achieve that "Hot Wheels" vibe I want. I know @Phsychographic did something similar with his bike "Cyrus the Virus," so doing something similar with car wheels doesn't sound like too much of a stretch. I'd still have to find someone to help me put all of that together, though.

That's one nice-looking trike you got there! If I could make it a bolt-on conversion, that would be the ideal way to go for me.
 
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I want to try an oxalic acid bath on this bike as I'd never done it before, and I'd rather mess up on this bike than mess up on the other bikes I'd like to try this on. Plus, if I mess up on this frame, it won't be an issue, as I plan to strip it down anyway.
Aahh, an experiment with no risk. That's logical. However, where would we be today if scientists took no risks? Just ask Victor Frankenstein or Henry Jekyll.
 
The Spaceliner trike with the added tubes might have been done for stiffness—these are really floppy frames and a trike would put more torsional loads on it.
 
The Spaceliner trike with the added tubes might have been done for stiffness—these are really floppy frames and a trike would put more torsional loads on it.
That might explain why I don't see Spaceliner trike conversions. If it turns out that transforming this bike into a trike would put too much stress on the frame, then I guess I'll have to stick with 2 wheels. Do you think I'd at least be okay if I stuck some stretched forks, like what you'd find on an OCC Stingray chopper, on this kind of frame?
 
I'm not saying it would break, just be prepared to have a high tolerance for a lack of torsional rigidity or you might want to reinforce it. I have a step-through Sears Spaceliner and Columbia Firebolt (basically the same thing, just Columbia's version). The Spaceliner was stiffened considerably by a TRM tank conversion—enough so that it is tolerable. The Columbia I didn't do anything to the frame and I thought it was almost unrideable. At first, I thought it was because they were cheap bikes made for a girl probably not exceeding 110 lbs and 5'4" almost sixty years ago and I'm 5'11" and around 175, so I have a lot more weight and leverage against the frame, but a friend borrowed it a few weeks ago and she's about the right size, if a little heavier, and thought there was something wrong with it for how flexible it was. It did motivate her to dig her bike out of the shed and get it going again, though!

For a fork, it uses an old American headset, so you'll have to convert it unless you can find something that fits that size. I'm running a 1-1/8" threadless Surly disc brake fork on the Spaceliner and I had to get a specific headset to convert it. I can't remember the brand and model now (and it's painted over), but it wasn't anything too obscure (maybe Ritchey or Cane Creek?), it just needs to have an OD to fit the head tube ID which may have been 1-13/16" (of course, measure it yourself, and don't go by my terrible memory from several years ago). As far as the ride goes, everyone's different and it seems most guys here are far more tolerant of frame flex than I am, so I'd recommend getting a front wheel on to get it rideable and seeing if you think I'm being ridiculous or not before spending the money to modify it. Know that it should flex more with a longer fork, but you'll have to decide whether you think it will be fine or not. I wish someone would remake these frames with modern tubing and better build quality as they're really stylish and I'd bet they'd sell decently as I've been seeing more classy looking step-through frames the last few years being ridden around.
 
I'm not saying it would break, just be prepared to have a high tolerance for a lack of torsional rigidity or you might want to reinforce it. I have a step-through Sears Spaceliner and Columbia Firebolt (basically the same thing, just Columbia's version). The Spaceliner was stiffened considerably by a TRM tank conversion—enough so that it is tolerable. The Columbia I didn't do anything to the frame and I thought it was almost unrideable. At first, I thought it was because they were cheap bikes made for a girl probably not exceeding 110 lbs and 5'4" almost sixty years ago and I'm 5'11" and around 175, so I have a lot more weight and leverage against the frame, but a friend borrowed it a few weeks ago and she's about the right size, if a little heavier, and thought there was something wrong with it for how flexible it was. It did motivate her to dig her bike out of the shed and get it going again, though!

For a fork, it uses an old American headset, so you'll have to convert it unless you can find something that fits that size. I'm running a 1-1/8" threadless Surly disc brake fork on the Spaceliner and I had to get a specific headset to convert it. I can't remember the brand and model now (and it's painted over), but it wasn't anything too obscure (maybe Ritchey or Cane Creek?), it just needs to have an OD to fit the head tube ID which may have been 1-13/16" (of course, measure it yourself, and don't go by my terrible memory from several years ago). As far as the ride goes, everyone's different and it seems most guys here are far more tolerant of frame flex than I am, so I'd recommend getting a front wheel on to get it rideable and seeing if you think I'm being ridiculous or not before spending the money to modify it. Know that it should flex more with a longer fork, but you'll have to decide whether you think it will be fine or not. I wish someone would remake these frames with modern tubing and better build quality as they're really stylish and I'd bet they'd sell decently as I've been seeing more classy looking step-through frames the last few years being ridden around.
Yeah, that all might prove to be a problem for me, as I'm probably twice the maximum weight those bikes were designed for at about 240 lbs. Granted, I am losing weight, slowly but surely, but if the bike feels flimsy for someone HALF as heavy as me, then I either need to reconsider my plans for this bike and save them for something else, or I'll need to figure out a clever way to reinforce the frame without sacrificing style. I love those TRM tanks, but I want to shoot for more of a 1970s coffin tank chopper vibe, and not so much a 1930s-1950s art deco streamliner vibe. Do you think adding a custom steel conversion tank might help stiffen the frame to tolerable levels, even with a moderately stretched fork? Or what about adding additional... what would you call the thinner top/side poles that give this frame its look?

I'll be honest Duchess, I got the gist of what you said, but I don't understand all the abbreviations and terminology you just used in that second paragraph. I'm still relatively new to the bike scene, and I kind of need things spelled out for me.

What if I just cut the steer tube off a fork identical to the original fork that came with the bike, and merged that with a custom stretched fork?
 
The TRM tanks are bolt on (thick) fiberglass, so steel could definitely be stronger, especially if welded on.

The old American style head tubes are a different diameter compared to typical newer bikes. I don't know which fork you're looking at, but I would imagine a triple tree kind of fork or anything extended would be 1-1/8" steering tube diameter and threadless, though there might be other options out there. However, the Spaceliner fork's steerer tube would be a smaller diameter, so the new fork wouldn't fit the original headset. To fit the likely larger newer fork, you need to change to a 1-1/8" head set. Since the inside diameter of the bike's head tube is odd by today's standards, you need to get a more unusual 1-1/8" threadless headset that has an outside diameter to match the bike head tube's inside diameter. Anyway, you can forget all that as I tracked down what I used: FSA "the Pig" 1-1/8" headset for a 34mm headtube (my memory was way off on the diameter!). I got it on Amazon and a few of the comments complain that it doesn't have the pig graphic from the photo and I couldn't tell you if mine had it or not, but that's the one I bought that fits and I checked the FSA website and it appears to be the same set also listed there as "The Pig". There may be others that fit, but that's the one I found and it's a solid unit that's much better quality than what the bike came with.
 
Definitely give it ride before throwing the baby out with the bathwater. I've ridden several 'flexy' bikes and haven't felt a thing different. I've done hi-ten, chromoly, carbon fiber, and aluminum forks and couldn't tell 'harsh' from 'springy' if you paid me. I'm 6'2" and have ranged from 190 to 270 since I've been back into bikes. I've seen a couple step through bikes from the 50s and 60s that were obviously bent in their lives, but the abuse must have been extreme. I mean, maybe some of these girls bikes were pampered for several years when bought, but most still have 40-50+ years of abuse and neglect on them and are so ubiquitous in useable condition that it is often a struggle to give them away.
 
The TRM tanks are bolt on (thick) fiberglass, so steel could definitely be stronger, especially if welded on.

The old American style head tubes are a different diameter compared to typical newer bikes. I don't know which fork you're looking at, but I would imagine a triple tree kind of fork or anything extended would be 1-1/8" steering tube diameter and threadless, though there might be other options out there. However, the Spaceliner fork's steerer tube would be a smaller diameter, so the new fork wouldn't fit the original headset. To fit the likely larger newer fork, you need to change to a 1-1/8" head set. Since the inside diameter of the bike's head tube is odd by today's standards, you need to get a more unusual 1-1/8" threadless headset that has an outside diameter to match the bike head tube's inside diameter. Anyway, you can forget all that as I tracked down what I used: FSA "the Pig" 1-1/8" headset for a 34mm headtube (my memory was way off on the diameter!). I got it on Amazon and a few of the comments complain that it doesn't have the pig graphic from the photo and I couldn't tell you if mine had it or not, but that's the one I bought that fits and I checked the FSA website and it appears to be the same set also listed there as "The Pig". There may be others that fit, but that's the one I found and it's a solid unit that's much better quality than what the bike came with.
I was thinking of having my welder guy fabricate a custom set of forks out of some steel plate and tubing. I'd really prefer to make it out of aluminum, but he doesn't really weld aluminum.
 
Definitely give it ride before throwing the baby out with the bathwater. I've ridden several 'flexy' bikes and haven't felt a thing different. I've done hi-ten, chromoly, carbon fiber, and aluminum forks and couldn't tell 'harsh' from 'springy' if you paid me. I'm 6'2" and have ranged from 190 to 270 since I've been back into bikes. I've seen a couple step through bikes from the 50s and 60s that were obviously bent in their lives, but the abuse must have been extreme. I mean, maybe some of these girls bikes were pampered for several years when bought, but most still have 40-50+ years of abuse and neglect on them and are so ubiquitous in useable condition that it is often a struggle to give them away.
Well, I might be able to slap some parts on it after this OA bath experiment and take it for a test ride, but I actually just found a trike version of this exact bike not too far from my home. Spotted it in the background of some pictures of another bike that's for sale on Craigslist. I've already talked to the guy over the phone, and he said I'm welcome to come over and take a look at it. I may stop by there a week from now, depending on what happens next week.
 
Well, this took a rather unexpected turn... I was originally just planning on checking out the Space/Flightliner trike, taking some pictures of it and how it was put together, asking some questions, and maybe even taking it for a test ride, but the guy offered to sell it to me, and I ended up buying the darn thing and bringing it home!

The guy wanted $200 for it, but we negotiated the price down to $160 for the trike and 3 chrome wheels he had that I wanted. I won't lie, I still feel like I might have overspent on it, but the guy needed the cash, and in regards to the trike itself, the sum of its parts is greater than the whole. The only way I could justify buying this trike was by saying this was what I'd buy with the change from my rainy day coin jar, instead of one of the $150+ Lego sets I had my eye on originally. It has a bunch of good parts I can use for my existing project bikes, and a few parts I could swap out and sell later. Best thing about this trike though is that it's actually rideable as is. Well, it was until I accidentally broke one of the joints on the trike part during one of those test rides. Luckily, I'm sure my local welder can fix it up quick, and maybe reinforce it too.

Crazy thing though is that @Duchess totally called it: I could literally SEE the frame flexing in front of me as I pedaled it around, though how much flex was from the frame vs. how much flex was from the springer fork, I don't know! This trike is the squirreliest thing I've ever ridden! I have some ideas of how to make it better, though how I do so remains to be seen...

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Well, this took a rather unexpected turn... I was originally just planning on checking out the Space/Flightliner trike, take some pictures of it and how it was put together, ask some questions, and maybe even take it for a test ride, but the guy offered to sell it to me, and I ended up buying the darn thing and bringing it home!

The guy wanted $200 for it, but we negotiated the price down to $160 for the trike and 3 chrome wheels he had that I wanted. I won't lie, I still feel like I might have overspent on it, but the guy needed the cash, and in regards to the trike itself, the sum of its parts is greater than the whole. The only way I could justify buying this trike was by saying this was what I'd buy with the change from my rainy day coin jar, instead of one of the $150+ Lego sets I had my eye on originally. It has a bunch of good parts I can use for my existing project bikes, and a few parts I could swap out and sell later. Best thing about this trike though is that it's actually rideable as is. Well, it was until I accidentally broke one of the joints on the trike part during one of those test rides. Luckily, I'm sure my local welder can fix it up quick, and maybe reinforce it too.

Crazy thing though is that @Duchess totally called it: I could literally SEE the frame flexing in front of me as I pedaled it around, though how much flex was from the frame vs. how much flex was from the springer fork, I don't know! This trike is the squirreliest thing I've ever ridden! I have some ideas of how to make it better, though how I do so remains to be seen...

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Looks rad to me! :thumbsup:
 

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