I need advice on a Cruiser to MTB build

[David Holler]

I haven't been on in awhile, its been a crazy 7 years here in TN. I am wanting to get into trail riding and am needing walls advice.

Im figuring out that I can't find a bike to buy and my wife and I think it might be best to try out trail riding before I dive deeper. So I have been looking for a cheep frame to add components to. While I have been looking I remembered I had a cruiser bike laying under my house. The weird part of me would like to make this frame work, I just don't know if the size and geometry is close enough. If I like trail riding enough and can stick with it then I would upgrade to something built for the purpose.

Some issues that I I don't know if they are issues
1, BB hight
2, HT angle and length
3. Handlebar to seat reach... what ever that is- will it be to crowded
4. Adding a disk brake in the back... some how? This bike is all aluminum

 

[MattiThundrrr]

AIl those geo numbers don't matter for what you are building. Forget em all. I'd say that trying to make it something it isn't (a mountain bike) will be more of a struggle than you want. You have to listen to the bike, help it become what it wants to be. You can make it a fine trail bike as long as you don't expect it to perform like a bike designed for the rough stuff. And those handlebars have to go. Cool for cruising, but you need something you can get on your feet and weight the front. MTB bars, bmx, maybe even dirt bike can provide sources.
I don't think you can realistically add a disk to that one. You would have to weld on tabs, and it's way trickier with aluminum.
In my opinion as a stable genius, you'd be better off with rim brakes in the rear, either using bolt on posts for v or cantilever brakes, or a u brake if there is a tube bridge connecting the seat stays above the rear tire.
If you are lucky, you might be able to get a fork with disks, but I couldn't name a source.

*Is that a derailleur or chain tensioner on the back hub? Because if you want the easiest route, coaster brake is an option for trails too, just takes some skill and fortitude.
I do light offroading; rolling singletrack, no drops bigger than a curb hop, a little bit of washed out gravel, on Duck Norris. The bars are the scariest thing, but that's only because I don't think about how junky the frame is

 

[us56456712]

It will work. Use a front brake in case your chain breaks. That will require a new front alloy wheel, but any old junk inexpensive Huffy type mountain bike can supply that. Make sure the new wheel doesn’t have wobbles or hops or the brakes will rub. Perhaps a different fork if your fork is nor drilled for a brake. A steel rim on the front won’t stop you, use alloy. A replacement fork has to have the threaded part of the fork the same length as what is on you bike. Look up Alan Bonds Clunkers on the net. Also look under the Klunkers and mountain bikes forum here on RRB. I would take flatter bars from an old cheap used mountain bike or cut down some old cruiser bars. The donor bike will give you the tires. You need a straight seat post. Your seat will work but perhaps a donor bike might have a better one. Your existing gearing looks like it could be low enough, depending on how strong you are. Your stem looks ok. Your crank arms might be a little long but that could be ok too. All these old bikes had small frames, long chain stays and a steeper head tube angle than a modern mountain bike. It should ride kind of like a modern all mountain bike, without a shock. Don’t worry about the cockpit reach, just get it to fit as well as possible with seat rise and handlebar rise. You will probably have your feet bouncing off those pedals. Try it out before investing in some BMX type spiked flat pedals. Your feet will still bounce off on the rough stuff but eventually you will learn to keep them on the pedals. You will also learn how to avoid most pedal strikes as you can’t pedal backwards as on a normal mountain bike. Klunking is a lot of fun. My bike here has cut down cruiser bars that were painted over the sanded off rust and chrome flakes.

 

[Wildcat]

The bike needs too much cost wise to make it feasible as a test bike for trail riding. The tires may be good, but you'll need tubes probably. The seat stem and handlebars need replaced and the ride may not be right, as the fork has a slight backward bend. There are no brakes. Either a coaster wheel or new brakes will add a lot to the total. Then the front wheel needs to be straight and all the bearings need to be good to make it useable. The costs will add up quick and after all that, it may not be what you like.
Craigslist for a cheap bike may be the best way to go. I took a look at a TN city, Memphis to see what's on there today. I saw a couple MTN bikes for under $75, and this cruiser at a decent price too. They may be cheap, but at least they are rolling and you can check them out before buying. Sometimes they haven't been ridden more than once or twice.
https://memphis.craigslist.org/bik/d/collierville-schwinn-cruiser-ss/7245461840.html

 

[David Holler]

Sorry I should have said that I would be only using the frame. But yes Im thinking it may be a bigger hassle to get this one working as a MTb then if I just found cheep MTB frame

 

[Wildcat]

Agreed! You can get a whole bike for a fraction of what a bunch of parts would cost you. You would need a big pile of parts to make a frame work. I've found a few people on CL that had piles of parts and just wanted to get rid of a lot of it cheap. That's where I found a Dyno in nearly new condition along with an Earth Cruiser. It just needed cleaned up and a few parts.

I did that myself also when I moved from the mainland some years ago, I sold a whole garage full of bike stuff for a hundred bucks. The guy's truck couldn't hold any more, it looked like Beverly Hillbillies as he left.

 

[David Holler]

Welp I found an old school Kona, almost in mint condition!

 

[Kevin B]

Nice find! Have you already tried it out on the trail?

 

[David Holler]

Just got it home tonight. ill take it out in the morning.

 

[MattiThundrrr]

Oh heck yeah, that's the easiest way to get a mountain bike. Steel Konas are really good frames. I'd say if you attempt any serious trail riding though, the stem might need to be changed, those adjustable jobs are just asking to fail at the wrong time

 

[Indyjps]

Good move, I was gonna suggest a 90's-00's high quality mountain bike. Most are chromoly frames, pretty god geo and had very good quality geoupsets.

I trail rode a trek 930 with rock shox for a few years and beat the hell out of it. Just kept coming back for more. 2 years ago found the exact same bike with little use for $75. Built it up for a friends teen son and he's banging away on trails. Had less than $150 in it with tires and tune up.