Upgrades to Fuji touring series IV

[Hartmame]

I'm try to help out an aging cyclist with upgrades to help with knee issues. One difficulty is with climbing the gearing on the Fuji touring series IV isn't low enough. I thought that switching out the front triple from 50-48-28 to a modern hybrid or MTB crank might help and keep costs low. I found two options Sunlite triple 48-36-26 and a shimano M-361
with 42-32-22. I know that the BB will have to be changed out. Is there any compatibility issues that I need to worry about if I'm running this with 6-speed cassette? Also the bike currently runs a 172.5 would a shorter crank be helpful for knee issues?

[Jean_TZ]

I’m assuming you meant that the current chainrings are 50-38-28 …right? If that is correct, then the effect of changing to the 48-36-26 would be pretty minor. The change to 42-32-22 should be very noticeable, especially with the smallest ring.

The only problem with the change to 42-32-22 is that your front derailleur might not cope well with the smaller rings. (The curvatures of the derailleur cage plates are designed work for a specific range of chainrings.) You’d have to try it out and see.

A shorter crank would decrease the range of motion for the knees. It would also make it easier to spin at a higher cadence.

[Hartmame]

Nope his chain rings really are 50-48-28. It's really difficult for him to make that jump to the smallest chainring when he has run out of low gears on the 48t ring.

I'm going to talk to him about the shorter crank arms and see if he thinks it would help. If we are Changing out the crank anyway and it would keep him able to ride longer we may as well make the switch to shorter crank arms ms at the same time.

[Hartmame]

A decision has been made and I hope it works. Turns out the chain rings are 50-45-28. Still top end is too big for him. We've decided to switch out the 45 for the 50 and add a 34 for the middle. We are leaving the 28 for now but I expect to swap it out for a 26 or smaller soon. I'm going to lower the front derailleur so it is at the correct height for the 45 tooth ring. I'll let you know how it goes.