Is there any advantage to switching the 53/39 Dura-Ace crank that is currently on my Litespeed Saber to a 50/34 R700? The rear cassette is 12-25. I was given the suggestion to switch after a VO2 max test, probably because my cadence was falling off in the latter stages of the test. I calculated the optimal crank length based on my inseam
; this corresponds to a crank length of 175 mm, which is in fact the length of my 53/39. The long-course events I plan to do this year will be very flat courses for the most part. Any thoughts? Thanks.
No - no reason to switch to a compact crank on a tri bike for sure! Especially if you are doing mostly flat courses. Just click up one cog!
Yes there is a reason. You just need to justify it for yourself. If the course is flat you will get a tight cluster of gear ratios with the compact and will find it easier to find YOUR optimal cadence. Look at the gear ratio charts. You will likely need a 11-23 in the back. Don’t worry about high and low gears because the compact would be comparable to 53/39 with the change in the back. Just get a compact with 175mm arm.
If it is fairly flat you might want to just switch the big chain ring to a 50 vrs swapping everything. I know that shimano has a dura ace 50 tooth 130mm chain ring as well as FSA. If you want a 50-36 truvativ compact crank 175 I would be happy to swap.
Changing your crankset to get easier gearing is a standard mistake. If you want easier gearing for climbing, look to the back and throw a 12-27 (Shimano) or even an 11-28 (SRAM) on there…When I did a flat course with my compact crankset I used only the big ring and a few gears in the back.
I agree with Macho Grande,
I rode a compact crank and I am 6’1" and i felt like* was *spinning cotton. Even after the ride when I was cooling down the small chainring felt akward and i just keep it in the big chainring. I will never go compact again. (and my wife feels the same she hated the feel of that stye of crank)
Just buy an assortement of cassette for different terrain. BUT ALWAYS make sure you got an 16 cog on there because that it the most used gear on a cassette cluster.
I was given the suggestion to switch after a VO2 max test, probably because my cadence was falling off in the latter stages of the test.
Is it possible that they were suggesting you were over-geared relative to your fitness?
I’ve been researching the same thing tonight. I found this thread and it pretty much answered all the questions I had:
http://forums.roadbikereview.com/showthread.php?t=104663&highlight=compact
I switched to compact with the switch to SRAM this year on my road bikes. I am a bigegr guy, 195 right now, should be racing at 180-185 this year. I am doing a 6 day stage race with 6 total Cat 1 climbs(if I remember correctly) then Highland Rim in TN. I initially felt like a wuss going compact, then I started looking at gearing. A 50/11 is a faster gear than a 53/12, and 34/23 is just a bit better climbing gear than a 39/25. So for crits, I’ll run an 11/23 and get really tight grouping. During the stage races I’ll run an 11/26 so I can spin up the big hills and really chase coming down. To me, it’s the best of both worlds. I’ll try it for a season and see where it goes. So far, I’ve got about 400 miles on them and like it.
My TT bike is staying 53/39 with an 11/23 though.
Given these circumstances, I completely agree with a compact crank. I have one on my road bike and like it a lot, but I only use a compact when I know I am going to be climbing a lot. Otherwise I keep my 53-39/11-38 set up on the Tri bike. I do agree that the 11 gear, whether on a compact or standard is pretty awesome.
Bob
Your cadence was falling because you were tired and pushing less watts.
Changing your cranks isn’t going to fix that… training will.
Compact cranks are a waste of money for flat time-trialing.
If you can get a chance to try a compact without buying one, I’d suggest you do so. You need to decide for yourself whether it works for you. As the various responses here and in the roadbikereview link indicate, some love them, others hate them.
I’ve been riding compacts on the road for quite a while now and find them useful for climbing. I usually ride with a 12-23 because I can get a fairly low gear and have reasonably tight ratios all the way along. (Note that the gaps on a compact are actually larger than a standard - 1/50 is bigger than 1/53). I also keep a bike with a 12-25 if I feel like doing a ride with a lot of climbing or if I’m traveling to a place where I don’t know how steep it will be. I also create a 12-29 when I go to Europe since I’m old and overweight and like having a 34/29 on long climbs. If Campy chainrings weren’t so expensive, I’d probably switch to a 36 inner. I may still try that.
Although I’ve standardized on compacts on my seven road bikes, I’m still not sure it’s the best way to go and it’s probably more a reaction to my declining climbing ability with age. I’m 57 now and today I go up climbs I did five years ago in a 39/23 in a 34/23. It just seemed easier to switch than to stand up when the gearing requires it. However, I think 52/39 or 52/38 (I’m not a great fan of the 52) is actually a better combination for strong riders since there is a range of speeds where you seem to be at one end of the cassette or the other.
I still ride with bigger gearing on my TT bike. If it’s not too hilly, I’ll go with 50-38 and an 11-23, or even a 12-23 if it’s really flat since I can spin close to 60 km/hr in a 50/12. If the course has a couple of big hills, I’ll switch to a 52-38 and 12-25. I like having one cog jumps in the gears I’m most likely to use. I wouldn’t go with an 11-25 very often since the 16 is an important gear at my average TT pace. The 12-23 gives me even tighter gearing if it’s really flat since I’m unlikely to push a 50/11 unless it’s really windy and the 18 can be helpful.
I race on 50 and 40-tooth chainrings and really like that combination now. I like the small 10-tooth jump on rolling courses where I am going back and forth. It also makes it easier to keep the chain in the middle of the cogs and maintain a straight chainline. I use a 12-25 in back, except at course like World's Toughest Half or American Zofigen where I switch out one of the cogs with a 28 off my mtb cassette.
Frankly, for a triathlete, I believe 95 percent of the riders are probably overgeared on a 53x39 combo. My bike splits at the end of the year were top 5 in races with 700+ folks, and I never use 50x12 and rarely the 13 either. I just time trialed on my personal bike/run course and used 46x34 with a 12 and I did not spin out until 50kph. At Worlds Toughest Half I pass a lot of guys on hills using a 40x27. I'm pretty sure their 39x23 or 25 gears were not cutting it on that course and they were spinning at 50 or 60 rpm.
53x12 is a bike racing gear where you are hammering along in a pack and need to stay in touch. I did races where we "dropped" a guy on a downhill and it turned out his smallest cog in back was a 13.
Any triathlete who claims he needs 53x12 either spins at 70 rpm, or is wasting his energy hammering down hills when he ought to be in a full tuck and not pedaling at all. Unless you are a TDF cyclist time trialing at 30 mph, most cyclist ought to be soft-pedaling beyond 25 mph and using their energy for going up hills.
Chad
.As someone with a 47 on his TT bike, and a 50 on his road bike, I’d have to agree–I’m having a hard time seeing why any triathlete would need anything bigger than that gear. A 47x11 is something like a 113"! That’s a big gear!! If I’m spinning that out, I coasting and getting into an aero tuck, to hammer the ensuing hill (that must be there if I’m spinning out that size gear). For a long course athlete, I’m not sure you really want to be pedaling if you’re going much over 35mph.
As expected Chad, right on.
Dave
I’m completely agree, a 53 is over kill for most people. Gearing that big is made for two things, sprint for short distance, and descending. Example at 90RPM on 700c wheels a 53x11 give you 33.9mph a 50 is 32mph. How is that not enough gear?
Yeah the jump between 34 and 50 is pretty good. Once i got use to it, i just planned my shifts better. I find unless I’m climbing a decent hill I’m usually in the 50 and with an 11-26 I’ve never had an issue getting the right gear.