USAF1C1X1

Hey everyone! This is my first post here. So, here's the deal. I love my 2010 7.3FX but I am ready to upgrade the drivetrain. I need something around the 50/39 (even a 30 for a granny gear if neceessary) area (roads here are pretty much flat). I know my BB is Square Taper, but can I upgrade the crank and BB to something that isn't? Also, I don't mind the rear cassette being 8spd but I have ridden around 2000 miles with it, so if I need to upgrade it as well I have no problem with it. Also, the front derailleur can't accomodate a 9 speed drivetrain so I'd need to change that also. Any suggestions for it? The rear is fine since I know the Deore can accommodate a 9 speed cassette so I'd like to keep it. If I change to a 9 speed overall I guess that means I need to change the shifters. I really just want to change the drivetrain completely to something that is geared more aggressively for flat roads. Does anyone have any suggestions? I am in the military and stationed in Korea so going to a LBS is out of the question. I can go to the bike shop on base for installation but I have to get the parts online first. I should have just gotten the 7.5FX but I have one in the states already. Also, I'd like to do this for around $300. Thanks to anyone who replies!

xoxoxoxoLive

Welcome to the forum ! If it were me, I would stay with the 8 speed, and just look for a wide range rear cassette, and a larger front chain ring...Like for the rear, a 11-32, if the roads are pretty flat, why worry about
the ( granny gear ), ? Richard

xoxoxoxoLive

Disregard my suggestion ) LOL ) , just looked at the specs on the bike...

bidaci

Your current gearing (48/11) should allow you to go 31.5 mph @ a cadence of 90. Your 7.5FX has the same top speed gearing. Looking at the specs the biggest difference is the 7.3 has more aggressive chainrings but the cassette is more MTB (11-32) then the 7.5 (11-26). Barring the fact that one is an 8 speed and the other is a 9 speed I would think that a simple cassette change to a more road type gearing would put you right in line with your 7.5. A 12-25 will give you the close spacing that you have on your 7.5 and you would only loose a little top speed (29 mph @ a cadence of 90).

qmsdc15

Thanks bidaci, for the comment on 48x11. A lot of people here on the hybrid forum feel they need taller gears, and I don't understand why. I know my legs are not as strong as many, and I depend on spinning higher rpms to maintain speed, but I can't spin out 48x11 on flat ground, let alone sustain it.

I ride the middle ring most of the time, having a 11 tooth cog allows me to go faster without shifting the front chainring, so I like having it.

USAF, do you use the lowest gears now? Would you be willing to give them up for a closer spaced cogset? If you are riding mostly in the big ring, the 12-25 bidaci recommends will give you closer spaced gears than a 11-26, which is good. For me, I'd get a 8spd 11x28. I don't think switching to 9 speed is really worth the money.

bidaci

q, did we agree on something?!?!?!?

I went from a 11-32 cassette on my MTB to a 12-25 to make it more road worthy and it does give the illusion of more speed as the closer spacing makes gear selection easier on the flats.

Personally, I have come to find out that I absolutely hate the wide MTB even when on my MTB. I have since switched to closer spacing on all my bikes.

USAF1C1X1

Thanks for the replies!
@qmsdc15: I am usually in the middle chainring in 8th gear. What would be a good recommendation for that? I am leaning against spending the money on a 9 speed because of the cost associated with it. I plan on giving this bike to my fiance when I get back to the states and she would be turned off by an aggressive drivetrain because she hasn't ridden a bike in who knows how long. If she doesn't like it, I would hate to have spent the money. However if that proves to be true, I would turn my 7.3 into a commuter which again means I wouldn't want to pour a bunch of cash into it if I don't need to.
@bidaci: If I choose to go with any of the recommended cassettes, would I need a new rear derailleur (Deore)? Also, what chain would you recommend? I would definitely be replacing that since I would rather not use a worn chain with a new cassette.

Thanks again for the replies!

bidaci

The only thing needed to swap the rear cassette is the right tools and a rear cassette. There are no extra parts needed for the swap. You can even save the old cassette and swap it back for your fiance (congrats). I would just use a Sram or Shimano cassette (nothing fancy) and a 8/9 speed chain (Sram or Shimano, again nothing fancy).

In a direct comparison to your 7.5, the 7.3 has a more aggressive gearing in the middle gear then your 7.5 (38 tooth vs 36 tooth).

Wanderer

My Advice, get a set of bolt on mini drops, Origin 8, from Niagara Bicycle.

Wrap 'em, and save your money for important stuff - I do remember what it was like to be in the military!

The 7.3 is a nice bike, just the way it is - use it up while you are there, and sell it to the new guy when you rotate.

USAF1C1X1

Those drop bars are pretty sweet. Ordered a flat bar a few days ago (can't stand the bar that came with the bike) and I am anxiously awaiting it in the mail. I considered Ergon bar ends but they are a little pricey for me. I might just end up with a new cassette and chain for the time being. I am looking at the SRAM PG 850 in an 11-28 configuraton. It seems like it is the best configuration for me since it will enable me use the gearing better. I am definitely going to read up on those drop bars though. Thanks for the info. Anyone else have any recommendations for a cassette and chain besides SRAM? Shimano seems to be pretty limited in that area.

bidaci

The Sram 12-26 8 spd is identical to your 7.5FX 9 speed with the exception of the 11 tooth cog. I don't think the 11-28 is really going to be that big of a difference for you. No matter what you do you won't be getting any more speed out of your middle ring. When you run out of steam on that ring it's time to shift into the big ring. I would bet that you are missing the close ratio of the 9 speed which will make shifting seem smoother and more seamless. A wide ratio gives you a lower gear for climbing but on the flats the jump between gears, compared to a close ratio, can make finding the sweet spot more difficult. If you are trying to duplicate your 7.5, I would suggest the 12-26. You should still have plenty of top end if you shift to the big ring.

I ran the specs for you.

7.3fx stock 11/13/15/18/21/24/28/32
PG 850 11-28 11/12/14/16/18/21/24/28
PG850 12-26 12/13/15/17/19/21/23/26
7.5 FX 11-26 11/12/13/15/17/19/21/23/26

USAF1C1X1

You put into words what I was struggling to articulate. Thanks! I will definitely try the 12-26 now with a PC-870 chain. Thanks again!!!