stcapp

i have this vintage bike i recently found out it was from 1941 from some very polite insightful people here on the forum, its not worth a whole lot so i decided to make it my own personal project for the summertime. It has 26" rims and tires and i was wondering if it was even possible to convert them to say 20" BMX style tires at the smallest maybe a little bigger if needed. Same with handle bars, basically i just wanna know if its possible for the modern style parts to fit on the vintage frame, ill add some pics so you guys can see the bike as it stands today...any insight will be greatly appreciated, thanks guys.

loky1179

When I was a kid, my buddy put a 20" front wheel on his Schwinn Typhoon. It LOOKED cool, but it lost most of the ground clearance for the crank arms. I doubt 20" on the front and rear would work. Why do you want to use bmx wheels?

Artkansas 

I suspect that the Classic and Vintage people would know most about things like BB diameters and threads and whether newer components are compatible.

stcapp

i just think it would look cool with the vintage style frame turned into a modern bmx style and ive always wanted to build my own bmx bike from scratch but im open to other options, its going to be my first type of build like this so we'll see what happens

Paramount1973

That is not a good bike to try to convert to 20 inch wheels. You will drastically lower the bottom bracket to the point that it won't be safe to ride.

Popeyecahn

Dude there's too much work to do in that frame set to make a BMX bike out of it (hell CL has crap loads of them to rework for less hassle and money). Might I suggest what Gary Fisher, Charlie Kelly did way back when with clunkers like yours?

https://sonic.net/~ckelly/Seekay/mtbwelcome.htm

https://mombat.org/MOMBAT/index.html

Start with a simpler project and work you way up and into your desired ideal when you have a better grasp and skill set required for the task(s).

Turning what you currently have into a proto MTB would be a fairly simple task, all things considered and it would be fully functional.

All you'd need are some cool MTB wheels, bars and brakes for mechanics and you could either strip the paint and repaint, or leave what's there to give it a total klunkerz look.

Yo Spiff

A guy I know did this fixed gear conversion with a similar frame. I like the way this looks. You may have to get some calipers and do some measurements on yours to know.

likebike23

Bikes like that were made into the first mountain bikes. They called them Klunkerz. Google Klunkerz for some pretty cool ideas, and if you finish it, pictures please.

Rollfast

I'd about be killing for that prewar frame but you do need to look up CLUNKERS (early balloon tired cruisers built up for dirt/off road use). You could have a lot of work getting a 72 year old frame up to snuff and you haven't pondered any possibilities of corrosion or stress that the bike has been through.

My best advice is to study up if you want to do this and in the meantime try a newer middleweight (Schwinn/Huffy/Murray/Western Flyer type cantilever frame) or a Stingray type sport frame first. My 250+ lb weight initially caused the bottom bracket of my 50s Rollfast to come apart at the tube welds until it was cross-braced with heavy duty welding and it came from New York State where it had probably spent most of it's life.

Another thought I have is will the truss rods take the beating or should you remove them or even replace the fork with a shocked example?

At this point I'd leave it as found and enjoy a really swell bike while reading up on what makes a good early MTB build and getting a real MTB, which are plentiful.

Since I don't know your age/size/weight at this point and have to assume you are a teen to adult rider of 5'5"-up and maybe 150 lbs I would think a 20" frameset is wicked small and inhibits your ability to create power. 26" or a 29er would be more ideal. Any good bike shop owner can help you find a bike that fits your frame based on your height and leg length.

By the way, is that a Rollfast? The headbadge area looks familiar but the chainring doesn't for a Rollfast.

For some insight into frame problems look throughout Bike Forums and my particular problems with the bike in my avatar can be found early in my Alt Bike Culture thread of six years Tempest--The Grey Bike Grows Up and the like named You Tube videos under my user ID steadfastcoward.

ilikebikes

You can convert it easily, just slap a BMX stem, a set of BMX handle bars, alloy 26 inch wheels (with BMX free wheel) and a BMX seat. All done. If you want to make it look more "BMXey" add vintage BMX brakes and calipers, or color match all the components. Get your self a one piece to three piece crank conversion kit and add a nice BMX crank. Its actually a VERY EASY conversion. Good luck, and post pics when your done.

Popeyecahn

Yeah, easy if the axle nuts, seat post, BB and headset/stem aren't frozen solid with rust. And like Rollfast pointed out, the frame integrity after 72 years of sitting in poor storage conditions may be very dubious. These are things to consider when heading into a project like this.

ilikebikes

None of the above mentioned is really a problem 'cept for the frame, but even then if the frame was that bad (inside) there would be major flaking or even holes somewhere on the outside of the frame. I know I've converted more than a few (for personal use) and have never had a problem with frame failure...ever. Anywaysits up to the OP to have faith in his own skills, as I do in mine. and if any of my bikes fail me lesson learned.

Rollfast

Maybe so but I just wouldn't do it personally, it's beyond RAT to my liking and it's probably causing the others to hesitate as well as they seem to be hung up over doing it to a 72 year old bike some as well.

Of COURSE you can.

Rollfast

Hey...maybe I converted a few to ancient bikes or something and it's just too darn NICE.

ilikebikes

Well the OP doesn't seem to interested in the replies so **** it.

Rollfast

You mean heck...

ilikebikes

Yup, I meant heck.

Popeyecahn

Maybe the OP is on a Quixotic quest for BMX parts...

Rollfast

Tempest was an east coast bike, the seller was in NY State so until I bought her she never strayed too far from HQ.