New member/front derailleur question?

redlitchfield

Evening!

I am completely new forum member as of this morning please forgive me if I have posted in the wrong area and/or repeating a previous question.

I cycle to work on a Saracen Urban X3 and would like to replace the front derailleur/3 cogs with a single cog and remove the front gears. This is purely for simplicity, less moving parts and the fact I never use the front gears and stay on the middle cog. As it stands I have no idea what replacement parts I need. I have recently replaced the rear derailleur(all the moving parts very worn and bent where I fell off!) and cable and re indexed it all. I am an engineer and am comfortable working on my bike but just a little unsure of specific terminology when it comes to push bikes and their components.

Any advice will be gratefully received. I can provide photos and measurements if necessary. Cheers!

fenix

Unless you need to replace the chainset - then I'd stick with what you have.

Your front mech doesn't need to move.

2 chainrings being used won't cause any hassle. I don't see the issue ?

JGTR

You need a narrow wide front chain ring and remove your front derailleur and gear shifter. There's lots of guides out there.

LimitedGarry

First thing to check is whether you can remove your chainrings. Some cranksets have the chainrings riveted on.
Once you confirm you can remove your chainrings, you need to figure out what cranks you've got. If you can't figure it out, you need to measure the bolt circle diameter (commonly just BCD). Circle goes through the middle of the bolts. Then you also need to figure out whether bolt pattern is symmetrical or asymmetrical (obvious to naked eye).
If google doesn't lie, you have Shimano Acera FC-M391, which do have removable chainrings and their BCD is 104mm symetrical. Don't take my word for it though. Check it yourself.

So once you know the BCD and pattern, you can order the narrow/wide chainring and you're done with the hard stuff. Don't forget to pick a fancy colour. The rest should be elementary to you. Mounting the chainring will require some spacers if you end up using your current chainring bolts (as they're meant for holding two chainrings). And you'll also need to check your chainline (there are recommended numbers, but it all just comes down to having the chainring in-line with roughly the middle of the cassette, preferably closer to the large sprockets). If you're unsure about anything as you go, there's a ton of guides online, but the whole process is very straight forward. You're basically just removing the front shifting and replacing a chainring. Should be easy enough.

redlitchfield

Excellent! Thanks for that in depth advice, it's perfect.

Obviously in the grand scheme of bikes it's a cheapy, but I've done various upgrades along the way and its perfect for me. I though as I've got it stripped down I'd look into it.

I've never come accross a BCD before, I've always referred to it as PCD (pitch circle diamter) when setting out bolt holes for lathing/milling etc, learn something new every day though!

As a new member, are there any other good areas of the forum to be nosing around in? I'm based in Northamptonshire and would like to where some local places to go trail riding are.