Single speed Dirt Jumper?

[Colby]

Ive been riding mountain bikes a good while. I have a good buddy who races cross country around the US and is crazy fast. I love to ride but hardly know anything about actually building a bike.

I used to have a mirraco 20forty single speed dirt jumper and got rid of it after breaking my collar bone. I love that bike and am building a bike to do the same.

Im using an old Marin 26er 15" frame. I know this probably isnt the best frame for a dirt jumper, but it definetly fits the bill for me (Have jumped some crazy stuff on this bike in MTB form) Its crazy light using V rear brakes, fox shock on the front, answer bars and truvativ head set and crank.

I have a really nice set of specialized 26in wheels and want to convert them to single speed. I have found some single speed conversions on ebay for crazy cheap, and just want to know what I need? I havent found any for a specialized wheel, but have found some that work for sram and shimano hubs. Would these fit the specialized?

Also, if any of you on here ride single speed dirt jumpers, what gearing do you use? Most of what I ride is down hill style, and I own a Kona stinky, but do not like riding that old death trap anymore

If you have one of these bikes, post up! Id love to see them

[jsowens]

Should be a fairly easy conversion. I converted a bike a while back to a rigid, single speed XC bike, which I occasionally commute to work on. Those single speed kits for the rear wheel should work fine on a Specialized hub if they're made for Shimano/SRAM freehub bodies. I assume the frame you have has a derailleur hanger on it...if it does, you'll also need some kind of chain tensioning device. On mine, I run a Summit Godspeed chain tensioner and it works awesomely.

Up front, you'll want to make sure whatever size ring you use is an actual single speed specific ring. You don't want a chain ring that has shifting ramps. It's also a good idea to use a single speed chain. In terms of gearing...I suggest figuring out what chain ring or crankset you'll be using, then figure the rear gearing out after that. I ran a 36/16 ratio on mine for a while for just around town commuting, but now it has a 30/20 to make it more hill friendly.

[Colby]

Awesome! Thanks for the info. I definetly want a chain tensioner anyway, just to keep breakage low. I want to spend money once on this thing

Good to know the conversions ive been seeing will work. This is what I have been looking at:
Conversion Kit Fixie Bike Single Speed with Tensioner 610696767707 | eBay

Here is the front crank that I was looking at. thought the color looked awesome:

SINGLE SPEED/FIXIE/TRACK BIKE CRANKSET CRANKS 165 RED | eBay

I guess that is all I need. The front shock I am using is a fox shock from my buddies bike. He said all I will have to do is trim down the neck a bit and it would make for a very comfy ride. I want to ride trails some with this bike. Alot of the trails I like to ride on have some sweet obstacles and they are very close together.

Thanks again for the info, I almost used a regular mtb crank

[athenscyclist]

Singlespeed Bicycle Conversions this is a good read

MTBR.com Single Speed Forum - Single Speed FAQ more info.

I have a single speed in the works. Trying to find a rigid carbon fork with V brake Tabs.

[jsowens]

That chain tensioner will work fine. It works on the same principal as the one I use, except mine uses spring tension to keep the chain tight and it looks like that one just adjusts into place. Honestly, a regular MTB crank would benefit you more than the crankset you posted. A track crankset won't be strong enough at all to handle much trail riding...it's just not designed for it and would likely not be strong enough.

If you have a MTB crank that has removable rings...you can attach a single speed chainring to it with the help of chainring bolts and spacers. On my single speed, I'm running a set of BMX cranks and chainring that I had laying around. They're a touch on the heavy side, but it was better than buying new ones.

[Colby]

Originally Posted by jsowens

That chain tensioner will work fine. It works on the same principal as the one I use, except mine uses spring tension to keep the chain tight and it looks like that one just adjusts into place. Honestly, a regular MTB crank would benefit you more than the crankset you posted. A track crankset won't be strong enough at all to handle much trail riding...it's just not designed for it and would likely not be strong enough.

If you have a MTB crank that has removable rings...you can attach a single speed chainring to it with the help of chainring bolts and spacers. On my single speed, I'm running a set of BMX cranks and chainring that I had laying around. They're a touch on the heavy side, but it was better than buying new ones.

Sweet! Thanks for the info. Saving me some money

[jsowens]

No problem. I've helped a few folks out with single speed conversions at the shop I work at. If you need anymore help just let me know. Also, post up a pic of the bike when it's done. I'd like to see it.

[twisted]

youre also gonna need some sort of chain stay for the front sprocket.

[Colby]

Originally Posted by jsowens

No problem. I've helped a few folks out with single speed conversions at the shop I work at. If you need anymore help just let me know. Also, post up a pic of the bike when it's done. I'd like to see it.

Will do! It looks really goofy, and almost non-dirt jumpish but I dont care. I know what I can do on it. As soon as I get my new wheels and the rear one converted I will post up. I really want to blast the frame and put a nice paint job on it, because this bike has been through hell.

I put a 29er front fork on it that is a rox shock? It has lockout and what not on it. Running a 26in wheel. That was my only option since my buddy needed his fox fork back

Originally Posted by twisted

youre also gonna need some sort of chain stay for the front sprocket.

I figured as much, My kona has a chain stay on it as well. Thanks!