Standard to Compact Cross?

[pbayne]

I'd like to change the crank on my cross/commuter bike. Its FSA gossamer 38,48 right now. I want the FSA compact cross Gossamer with 36,46. Is there anything I need to do besides swap cranks and maybe shorten up the chain? Will the derailleur work the same (105 double)?

I also want to do the same to my road bike, ultegra 39,53 to an FSA Energy 34,50. (ultegra der.)

Paul

[sourceofdenial]

Just swap the cranks, maybe remove a link from the chain if you need to.

Why the swap to compact? I dont want to be a naysayer, but honestly, I think the compact trend is kind of unnecessary. I ran a 50/34 on my cross bike when I used it briefly as a road bike(before switching to just a 42) and then my road bike uses a regular old 53/39. I just have a few cassettes, if I'm going to go climb in the shenandoahs, I'll put on a 12-27. But if I couldnt get up it on a 27-39, chances are a 27-34 isnt going to make life much easier.

I would save the money personally, get a 12-27 and a 11-23 cassette.

Edit: I just looked it up, for reference, running a normal road tire and a 12-27 cassette, going to a compact cassette drops you gain ratio by only .3. You can run chainrings that are not 50/39 or 48/38 on your 130bcd cranks(Harris sells them, so does pretty much anyone else who can get things from QBP or whatever bicycle product distributor they use) and switching to a smaller chainring, even by one, reduces your gear ratio. This is easy to accomplish, can readily be switched back, and as long as your front derr. can handle the tooth difference, essentially accomplishes the same thing.

I think the whole compact thing is mostly in peoples head.

[g_barr]

I'd like to change the crank on my cross/commuter bike. Its FSA gossamer 38,48 right now. I want the FSA compact cross Gossamer with 36,46. Is there anything I need to do besides swap cranks and maybe shorten up the chain? Will the derailleur work the same (105 double)?

I also want to do the same to my road bike, ultegra 39,53 to an FSA Energy 34,50. (ultegra der.)

Paul
Front derailleur? It looks like the 105 doubles have a maximum chain ring difference of 15 teeth - you "should" be fine. You will need to slide the derailleur down the seat tube, adjust the cable and possibly reset the limit screws.

[DaveG]

I think the whole compact thing is mostly in peoples head.

I can most definitely tell the difference between 34x27 and 39x27 in some of the hills I ride around Frederick. It's the difference between painfully mashing up some of those hills and spinning a decent cadence.

Dave

[plojaa]

I can most definitely tell the difference between 34x27 and 39x27 in some of the hills I ride around Frederick. It's the difference between painfully mashing up some of those hills and spinning a decent cadence.
Dave

I went to a 50/34 FSA compact on my road bike a year ago and I climb much better. I always had a hard time - felt like I ran out of gears but w/ a little wider ratio set I have those gears and I don't think the likelihood to spin has slowed me down. It really depends on the person....try it and see how it goes. I also run 46/36 on my cross bike and find that works great. Some folks swear by compacts and some dont'. BTW... I noted FSA now sells compact crank chain rings of 52/38 - so worst comes to worst you can get back to almost a 43/39.

[sourceofdenial]

Meh, not a believer after trying both. The difference in rollout between a 34x27 and a 39x27 is only 5 inches on a given bike. I used a compact when I lived in Colorado, and did a lot of climbing, and then used a standard crank when I lived in new england, which arguably has 'steeper' hills, and honestly, didnt think the crank was holding me back or making me any slower. I would anually do this ride: http://www.northeastcycling.com/six_gaps.html and the GMSR uses App gap for two stages, and never once during any race was I thinking, damn, I wish I had my compact. It was always, damn, I wish I was in better shape, or damn, I wish this didnt hurt so bad.

The only times I really noticed a difference between the two was when I was needing to pedal down a hill, and I had to get into a much deeper aero position because I would run out of a gearing with a 50x11 versus a 53x11 earlier.

No matter what you are riding, you always do that little tap of your shifter on that big hill just to check if you have another gear. I really don't think my cadence changed that much from one crank to another over the long haul. There was a difference the first two or three rides out, but thats about it.

The only time I could see it being useful is for someone who doesn't ride much at all and needs that extra spin for motivation. But for folks who ride regularly, you usually have a pretty set tempo at which you pedal at, and its really hard to change that. Going to a compact will probably just make you pedal slower.

But it doesn't make hills easier. If it did, everyone would have switched.

Just putting it out there, if you expect a compact to change how you ride, or make life easier, it really wont do that. Or at least it didn't in my experience. You get used to it, and you set a new baseline.

[pbayne]

Thanks for answering my questions, and for debating the whole idea.

The only reason I am going to compact for the cross bike is that it came with 172.5 cranks and a standard cross 38,48. My other 4 bikes are 175 cranks. I wanted to get them all in line and had access to a friends compact cross set at 175 with the 36,46. I don't expect to feel any real difference here. I swap between 3 different cassettes if I really need to change the range anyway.

For the road bike I'm going to compact so that (all others thing being equal) I can spin a slightly higher cadence on long climbs. This is mainly to protect my knees during cold winter hill climbing and to hit cadence/heart rates targets better during the winter. For crit racing I'll probably put the standard crank back on. For training I want to go 34,50 up front and 12-27 out back. Once the race seasons gets going I'll be back to 39,53 and 11-23.

[DaveG]

Meh, not a believer after trying both. The difference in rollout between a 34x27 and a 39x27 is only 5 inches on a given bike. I used a compact when I lived in Colorado, and did a lot of climbing, and then used a standard crank when I lived in new england, which arguably has 'steeper' hills, and honestly, didnt think the crank was holding me back or making me any slower. I would anually do this ride: http://www.northeastcycling.com/six_gaps.html and the GMSR uses App gap for two stages, and never once during any race was I thinking, damn, I wish I had my compact. It was always, damn, I wish I was in better shape, or damn, I wish this didnt hurt so bad.

The only times I really noticed a difference between the two was when I was needing to pedal down a hill, and I had to get into a much deeper aero position because I would run out of a gearing with a 50x11 versus a 53x11 earlier.

No matter what you are riding, you always do that little tap of your shifter on that big hill just to check if you have another gear. I really don't think my cadence changed that much from one crank to another over the long haul. There was a difference the first two or three rides out, but thats about it.

The only time I could see it being useful is for someone who doesn't ride much at all and needs that extra spin for motivation. But for folks who ride regularly, you usually have a pretty set tempo at which you pedal at, and its really hard to change that. Going to a compact will probably just make you pedal slower.

But it doesn't make hills easier. If it did, everyone would have switched.

Just putting it out there, if you expect a compact to change how you ride, or make life easier, it really wont do that. Or at least it didn't in my experience. You get used to it, and you set a new baseline.

And I do understand where you're coming from. I'd guess that you're probably a pretty strong rider though. I went from a triple crank to a double w/ a 39/27 low gear and I actually got faster up even the nasty hills, simply because I couldn't down-shift. Of course I switched out in the middle of the summer when I was in shape. I did some of those rides in the early spring last year and I was really hurting and my knees were suffering. I bought a compact crank soon after and it did make a difference. It may be only 5 gear inches, but that's close to a 15% lower gear.


Nothing EVER makes hills easier; you just spread the pain over a longer time ;)

[plojaa]

The only time I could see it being useful is for someone who doesn't ride much at all and needs that extra spin for motivation. But for folks who ride regularly, you usually have a pretty set tempo at which you pedal at, and its really hard to change that. Going to a compact will probably just make you pedal slower. But it doesn't make hills easier. If it did, everyone would have switched.


Naturally everyone's experiences vary so its fair to say that what may work for one does not work for another....yes you get used to it - just like going between campy/shimino shifters. When I cut over to compact - I now climb with the guys I could not climb w/ before...so go figure....I might be spinning more and maybe my old legs like that.....I've not switched back to see what a 39 is like again after a year w/ a 34. I do miss the high end a bit but I'm not racing crits so don't need that - a 50/11 works fine. FWIW I have a 55/44 on my tandem...can't imagine riding that w/o that - it came w/ a 53/39 and I would spin out....yet many folks ride a tandem w/ std chain rings. Its what ever works .... And I put in alot of miles a year!!!