Phil221

Hi, I'm quite new to the whole technical part of biking. Up to now I only rode them.

The problem I have is that I have to prepare my bike for my first road trip and I'm quite a bit limited by time.

My bike has a
Shimano Sora FC-R3030 50/39/30 crank
BB: Shimano Tiagra BB-RS500
FD: Shimano Sora FD-R3030-F
with a friction shifter
and at the back a Shimano Alvio 9 (11-34).

This has worked well without luggage but I'm afraid it won't work so well with luggage and hills.

I haven't found any smaller chainrings for the Sora crank but from what I have read a 44/32/22 crank should work well enough.

The only available option I found though was a Shimano Alivo FC-T4060 44/32/22 crank which I have ordered but not received yet.

In the meantime I have found out that the difference in chainline will make problems (45 old crank, 50 new).

Would be awesome if anyone of you has an idea what I could do to make this work in a short amount of time.

Thanks, Phil

10 Wheels

The 44/32/22 is mountain gearing. You will be Fine.

Phil221

What about the difference in chainline?

Tourist in MSN

I threw Shimano Sora FC-R3030 into google and found a four arm crank and a five arm crank.
https://bike.shimano.com/en-EU/product/component/sora-r3000/FC-R3030.html
https://bike.shimano.com/en-EU/product/component/sora-r3000/FC-R3030-CG.html

One option would be to get a smaller innermost chainring and install that on your existing crank, but I have no clue if you have a four or five arm crank.

This link appears to be pertinent:
https://dassets.shimano.com/content/...3030-4153A.pdf

That link lists both cranks as having a 74mm bolt circle diameter (BCD), thus you could try to find a 24 or 26 tooth granny gear to use.

I use a 24T granny gear, five arm 74mm BCD, so I know they are available for five arm, but not sure about a four arm asymmetric bolt pattern.

Phil221

Sorry I had posted all my parts with links to them, but was not able to publish it because I had less than 10 posts.

Unfortunately I have the 4 arm and I couldn't find any smaller 4 arm chainrings with 74mm.

cyccommute 

The change would be relatively trivial. Since has an external bearing, you just have to loosen the cinch bolts on the old crank, pull the left arm, and pull out the crank. Reverse that to put in the new one. You will have to lower the front derailer. If you have to plastic block that comes with new derailers, even that is easy. Most people throw away the block or it doesn’t come with a new bike. The block holds the derailer out over the large ring and makes alignment easier. You can use a bolt or piece of card board to do the same. Make sure the outer plate on the derailer is parallel to the rings and that the bottom of the derailer clears the top of the outer ring by about 3mm (use a nickel to gauge).

It isn’t much of a problem. Most likely the road front in the current configuration won’t move far enough out to get to the outer ring. Remove spacers on the bottom bracket from the right side and add them to the left. That will move the crank inboard enough. You may want to get some thinner spacers (they come in 0.75mm thickness) if you need to fine tune.

Tourist in MSN

Using a nickel is a GREAT idea. I always eyeballed it and often had to re-adjust. Thanks.

Phil221

I received the new crank today, replaced it and everything works perfectly.
The old crank had a 6.5mm spacer (number 11 in the pdf link above) on the drive side which I haven't used anymore. On the other side I used an O-ring which I had lying around as a spacer.

Thanks all for your help!

Edit: And by the way, the new configuration feels so much better. Fast enough downhill but also quite capable uphill.

cyccommute 

The o-ring might not be a good choice. Too squishy. The spacer needs to be rigid so that it doesn’t squeeze out and loosen the bottom bracket.