New bike project

[gazza81]

Well this is my problem, new crank arms are straight...

 

[si_c]

Chainstays tend to be spaced wider on a MTB than a Road bike especially when combined with disc brakes, and some MTBs have a 73mm rather than 68mm BB shell which spaces the cranks wider anyway. Also the rings tend to sit further outboard on an MTB crankset than on a road one. You might be able to get a wider BB shell, I think Sunrace do one over 130mm.

When I did my 1x conversion recently I used the triple crankset and put a single chainring in the middle position and kept my existing BB, for me that ended up being the best option.

 

[gazza81]

My BB is 73mm and 125mm so not sure getting 130mm will be enough of a increase to the width.

When I did my 1x conversion recently I used the triple crankset and put a single chainring in the middle position and kept my existing BB, for me that ended up being the best option

I cant picture what what you mean have you got a picture of it?

My other option is to buy an MTB crank that will be a bit wider, there's a Suntour xct for 20 quid it's a triple but they can be separated

 

[si_c]

My BB is 73mm and 125mm so not sure getting 130mm will be enough of a increase to the width.
I cant picture what what you mean have you got a picture of it?
My other option is to buy an MTB crank that will be a bit wider, there's a Suntour xct for 20 quid it's a triple but they can be separated

Not at the moment, I'll try and take one later.

Essentially I had 3 rings at the front and a shifter, so I took the shifter off, removed the triple ring crankset, removed the three rings and where the middle ring would screw in I put in a single narrow-wide chainring. It's the same arms, so basically it's like riding in the middle ring all the time.

If you took the outer and inner rings off your old crankset you might achieve more or less the same objective.

 

[gazza81]

Unfortunately my old crank is riveted together and the Rings can't be removed but that was what I want to try and achieve, riding in the middle ring all the time

 

[si_c]

Unfortunately my old crank is riveted together and the Rings can't be removed but that was what I want to try and achieve, riding in the middle ring all the time

View attachment 476950

Ah ok, yes if your crankset is riveted then that's no help. It might be worth looking for a second hand crankset that isn't riveted that you could do the same as you did with the road based one, especially as that would sort the clearance issues out. Might be a better all round solution than trying to push the road crankset out further than intended.

 

[gazza81]

Yeah im thinking this, 22 quid

 

[si_c]

Looks good, should be a solid 104bcd for the outer/middle chainring - so you should be able to use a most 4 bolt narrow-wide chainrings. Just double check what BB spindle length it needs.

 

[gazza81]

It says recommended use is with 113mm bottom bracket, mines about 125.

Why does it make a difference? Surely that Arms just push onto the square tapered part?

 

[Threevok]

It says recommended use is with 113mm bottom bracket, mines about 125.

Why does it make a difference? Surely that Arms just push onto the square tapered part?

Yes but the part at which they stop is wider on yours

 

[gazza81]

Ok think i understand, alot of them dont even specify the best suited length

All the ones i have saved are either 113mm or dont say.

Cant find anything else really not cheap anyway

 

[gazza81]

I've seen a Carrera kraken frame i might buy because it's got a few bits on it that I could use and it's cheap

The Halfords website says sealed bearing bottom bracket, it's the right width 73 mm

Does anyone know if that would fit my frame?

 

[Threevok]

I've seen a Carrera kraken frame i might buy because it's got a few bits on it that I could use and it's cheap

The Halfords website says sealed bearing bottom bracket, it's the right width 73 mm

Does anyone know if that would fit my frame?

Yes yours is also a 73mm.

It's the width that's the most important (probably 113mm)

Despite that, if you are using the crankset off the donor bike also, there should be no issues.

As you are going 1-up on the front, then any difference in the chainline can be altered with spacers, but I doubt if you will need to

 

[gazza81]

Yeah im planning to use the cranks and im hoping they can be seperated!

 

[Threevok]

Yeah im planning to use the cranks and im hoping they can be seperated!
View attachment 477089

They'll do very nicely

You may be able to sell the frame on for a couple of bob too