Triple (mtb) crankset for old road bike SS conversion?

[kaiseris]

Noobish question. I'm going to convert my 70's road bike to SS. Since it has cottered cranks I've bought another used cotter-less crankset on ebay. Since chainrings are bolted by 5 bolts I assumed it's comes from a road bike. I haven't noticed third chainring then. Now I started to doubt if triple crankset was a good purchase. I know I should have done my research earlier...
It's a Exage 300LX crankset just like the one in picture bellow.
Is such crankset usable for SS conversion?

 

[TheDoctor]

Should be fine. Get a set of single chainring bolts, and lose the other two chainrings.
If you're using a singlespeed conversion for a freehub rear wheel, then sorting the chainline out is as simple as a simple thing. If you're using a freewheel, things get a touch more fiddley.

 

[kaiseris]

Thanks for calming me down. Could buy another crankset but I'm trying to keep costs down. At least till I know I really like it. I've already managed to spend more on that bike than it's worth. And it's still not going well. Derailleurs brake, cottered BB is wobbly. Hence the conversion. Want to give that bike another chance and try something simple.
Because of the costs I will be keeping original wheels with freewheel. So probably will be posting about chainline problems too

 

[chriswoody]

I've just converted an early nineties Dawes Racing frame and to keep costs down I used a double chainset which I then dropped the inner chainring from, I'm sure you could do the same with a triple. The outer ring will be just a little further outboard of where mine is. Luckily my chainring bolts tightened up still despite the missing ring, but you can soon buy shorter ones if need be.

Like TheDoctor recommends I bought a Surly spacer kit to fit on my freehub and this allowed me to perfectly align my chain in the straightest line possible with the front chainring. I looked at several kits and the surly one offered the most amount of spacers which allowed for greater fine tuning and much more chance of a perfectly straight chainline.

 

[kaiseris]

My bike is older and I will be using original wheels. So it's a screw-on freewheel in my case. Won't be that easy to sort out the chainline. I've already ordered shortest BB (103mm) and hope it won't be too short
Sturmey Archer freewheel and single chainring bolts are also on it's way.

 

[kaiseris]

Just in case someone has same question. Finished converting my bike yesterday and had first ride on it.
Had to grind of mounting points of third chainring. Bought a 103mm BB (needed one anyway because of cottered original crankset). Also took back wheel to LBS for re-dishing. That's it, got near perfect chainline.
Learned the basics about bikes in progress. Totally disassembled the bike myself for sandblasting/powdearcoating and re-assembled it. Everything about bikes seems a lot less daunting now.

 

[kloeshuman]

I used a double road crank for mine and got the shorter chainring bolts. I ended up setting my chainring on the inside so I could get the chain line easier. Worked out great for me, when you move the chain ring to the inside of the spider you have to turn the ring around so the bolts will drop into the recess on the ring. I know how you feel, after building up my carbon road bike this winter Im not afraid to tackle anything on the bike.

 

[kaiseris]

Chainring was too close to chainstay when I moved to the inside. There was like 5mm gap max so I thought I'll better move it outside and take the wheel for re-dishing to be on the safe side. Otherwise I could have got away without re-dishing.

 

[kloeshuman]

Did you get a new chain ring or are you using one from the crankset?

 

[kaiseris]

I'm using ring that came with the crankset. Wanted to test how I like the ratio and this bike in general before splashing out on a new chainring. 110BCD 48T chainrings not that common ant relatively expensive.

 

[kloeshuman]

ok, that may be the problem then with the play, I ended up getting a 45t I think it cost me around $20 then the shorter bolts were another $10 I think. Now I'm playing with different cogs, started off with 45x17, and just picked up a 15t, the 45x15 gives me 79.1 inch gearing. A little hard for big hills but I'm liking that combo

 

[kaiseris]

I got the shorter bolts too. Original ones would be too long since they hold two chainrings. Just the old chairing was left. Chepest chainrings (110BCD 48T) I found were about $55 hence leaving the old one for now.
I run 48x18 and it suits me so far.