After riding the Lake Placid course this weekend and reading the post below regarding gearing for Lake Placid, I’ve decided that I’d like to put a compact crank on my Cervelo Dual. The stock crankset is a FSA Gossamer 53/39, not the best crankset in the world, but it’s worked just fine for me. I see that REI sells just the FSA chain rings separately http://www.rei.com/product/723306. Is it possible to use my existing bottom bracket and crank arms, and just install a set of 50/34 chainrings? If this is possible, it seems much more cost efficient than buying a complete compact crankset. Also, are the bolts holding the chainrings on re-usable and do I need anything else to make this work?
If the BCD (Bolt Circle Diameter) is the same, you sure can just buy new chains rings. Compacts are usally 110 BCD, but if, as I assume, the Goassamer has a 130 BCD, then you need a new crankset to run compact. I don’t know of any 130 BCD compact rings.
What Bob said. You can get a 50T in 130BCD, but unless something has come along recently that I’m unaware of, you won’t be able to get the 34 in a 130BCD. I tried to do the same with a Zipp crankset I had about 3 years ago, and ended up selling it to get a true 110mm BCD compact.
I also have a Dual and have the SRAM Force compacts on mine with a 12/27 in the back. The cranks cost about $175 if I remember correctly. Not “too” bad, and it works great.
I have an FSA SLK Compact for an ISIS bottom bracket on my TT bike, and a Stronglight Pulsion (ISIS) on my road bike. I’ve had great success with both. Given that you have a Shimano 10 speed setup, and assuming you are already using Shimano cranks, you’ll want to probably choose something that will permit you to re-use your exiting bottom bracket. The first logical choice is probably the Shimano R700 compact (http://www.excelsports.com/new.asp?page=8&description=Compact+Road+Crank+R700+10sp&vendorCode=SHIM&major=1&minor=13). If you’re OK with Ebay, you can probably get it delivered south of $200. FSA would likely be your second option. I THINK they work with the external Shimano bottom bracket cups, but you’d want to double check that.
What year Dual do you have and does the FD Hanger being too high impact the shifting at all? I was told by Cervelo that I cannot put a compact on my late-06, early 07 P2C due to the FD Hanger being too high and they could not gurantee shifting performance.
If the BCD (Bolt Circle Diameter) is the same, you sure can just buy new chains rings. Compacts are usally 110 BCD, but if, as I assume, the Goassamer has a 130 BCD, then you need a new crankset to run compact. I don’t know of any 130 BCD compact rings.
Bob
Slight hijack…Why the hell don’t crank manufactors make chainrings interchange able? What reason do they put 130 BCDs on 50/39s and 110 on Compacts. Are there performance benis to do this?
It would be nice to have a crank that one could buy a range of chain rings and swap them out much like a cassette depending on the course. I realize that RD and chain issues might happen, but those can be adjusted for the most part or someone could buy a long cage RD.
I think it would be benificial to me to have a 53/34(or 30) (or something like that). I know, I know, it might not be possible due to chain/rd issues, but I hope you see my point.
I have a late 06 - early 07 Dual (the silver one). The FD still has some room to be lowered. About how much extra space is required on the FD bracket to go from a 53/39 to a 50/34?
Well - more correctly - the 50/34 is for SRM - checking again - the best you could get for FSA/shimano is a 52/36 in a 130 BCD - however that is what I run as compact riding in the Blue Ridge - you have a pass through at the dead spot of approximately a 50/34 - with the maximum diameter being about a 54/38 - with an SRAM 11-28 I regularly handle 16% grade, and I am not a particularly strong cyclist.
I switched out from a rotor 50/34 for this, and the only change I had to make was to go to an Ultegra triple FD to get the clearances to prevent chain rub (was running SRAM). What I like about this setup now is the elongation in the gear during the point where you are putting the most power to the pedal is I getter much better speed on the flats than with a conventional 50 ring. This setup would easily do Placid, if my reading of the grade is correct.
qrings do not come in 50/34 in 130bcd. they only make the compact rings in 110bcd, like everyone else. the smallest inner ring currently available(qring) in 130bcd is a 40 tooth, although a 39 tooth in just coming out. in order to make the 39 tooth they had to make it a little less elliptical to fit the bolt circle.
the reason that nobody makes a compact set in 130bcd is that the inner ring would not be large enough for the mounting bolts. the reason that manufacturers don’t just make the 110bcd standard for everything is that the larger rings would flex too much. there are some aftermarket 38 tooth inner rings in 130bcd, but going with a whole compact setup makes more sense. there are many affordable compact cranksets out there these days.
probikekit.com has ultegra compacts for 150 shipped. It will not take any time at all to get used to them and I had no issues at all with shifting performance when I switched, just lowered the FD a tiny bit.
What year Dual do you have and does the FD Hanger being too high impact the shifting at all? I was told by Cervelo that I cannot put a compact on my late-06, early 07 P2C due to the FD Hanger being too high and they could not gurantee shifting performance.
According to Cevelo (and I’ll take their word on it) that won;t work and the only one that MIGHT is the SRAM. The FD hanger is too high and the FD cages simply aren’t long enough to drop the chain properly. The issue was resolved with the mid-2007 models.