# Cranks: DA7950 Praxis vs Ultegra 6800



## stealle (Aug 31, 2013)

I'm getting a Specialized Roubaix SL4 Comp. It has mostly Ultegra components, but of course they went cheap on the crank. I'd like to replace the BB for the OSBB Shimano compatible Praxis Works BB in order to get a Shimaon crank on this bike. I was going to go with Ultegra 6800, but then I saw on Praxis website they have a Dura-Ace 7950 crank that is fitted with Praxis ring-set. I'm not sure which one to go with.

The Ultegra 6800 is new and based upon Dura-Ace 9000 tech. The Praxis Works/Dura-Ace 7950 crank is slightly older tech and I just don't know anything about the reputation/durability of Praxis Works chain rings. I can get them for the same price.

Also, the Praxis Works BB is available with ceramic option described as _"Angular contact steel race, ABEC5 Assembly, Grade5 Ceramic balls" _for about $100 more. I realize the ceramic bearings only give a <1 watt advantage, but I'm interested in durability and a quiet BB. Which one will give me that?

Some personal info if needed:
Why do I want to replace the original crank? Because I want all Shimano components. 
I'm 6ft tall. Weigh 200lbs. Ride about 150 miles a week. Would like to do a couple centuries this year. Mostly ride on flat chip/seal roads. Not many hills, but occasionally lots of wind on these open country roads.


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## tihsepa (Nov 27, 2008)

I have ridden Praxis rings. Nothing shifts as smooth as Shimano rings. Period.


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## Kerry Irons (Feb 25, 2002)

stealle said:


> Also, the Praxis Works BB is available with ceramic option described as Angular contact steel race, ABEC5 Assembly, Grade5 Ceramic balls" for about $100 more. I realize the ceramic bearings only give a <1 watt advantage, but I'm interested in durability and a quiet BB. Which one will give me that?


Ceramic bearings on a bike are 100% a waste of money. There are frequent reports suggesting they are no more and quite possibly less durable than steel. Quiet is all about the combination of basic design and proper installation, not about bearing type.


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## JSWhaler (Nov 25, 2009)

I run a da 7950 crankset and after everything I've read, I'm sticking with the shimano rings. In addition I've used ceramic bb's before. They may be blingy and all but in reality while pedaling you won't notice much of a difference and they don't last as long. Buy yourself the dura ace bb and be done with it.


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## Roland44 (Mar 21, 2013)

tihsepa said:


> I have ridden Praxis rings. Nothing shifts as smooth as Shimano rings. Period.


+1 on this,

I tried almost everything on the market and Shimano is where I personally saw the best results. Amazing quality and functionality.


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## masont (Feb 6, 2010)

I have suggestions:

To start off, I love Praxis rings. I think they're the best aftermarket ring out there. I recommend them wholeheartedly to just about anybody looking for aftermarket rings. That said, they aren't as good as Shimano's. Shimano makes better chainrings than anybody else. If it were my dollars and I decided to replace the crankset I would get 6800. It matches. It shifts great. You'll love it. 

That being said, the comp "went cheap" in a few spots (in order to hit the pricepoint that is probably the reason you didn't buy the expert), and if I were ranking things to replace, I wouldn't start with the crank. I'd start with the brakes. Those axis brakes are crap, and the 6800 brakes rock. 

Instead of $100 on ceramic bearings, you should send me $50 and I will do an old Indian "bearing dance" that will give you all the benefits of ceramic bearings at half the price.


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## masont (Feb 6, 2010)

Also, you said "I'm getting."

If you haven't bought it yet and you're talking upgrades already, I'd just buy the expert. It's $900 more, but you get a better frame, better brakes, better wheels, a better crank, a better seatpost - if you're already talking upgrades that are going to cost you around $400, why not just buy the bike that has upgrades at those spots anyway?

Full disclosure: I work at a Specialized dealer, my current road bike is an Allez expert that has the same kit as the Roubaix expert. The SLK crank that comes on it is very good despite the fact that it says FSA on it. The rings are quality, it shifts great, and it's plenty stiff.


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## stealle (Aug 31, 2013)

Kerry Irons said:


> Ceramic bearings on a bike are 100% a waste of money. There are frequent reports suggesting they are no more and quite possibly less durable than steel. Quiet is all about the combination of basic design and proper installation, not about bearing type.


Aside from the ceramic bearings. The ceramic option includes: "Angular contact steel race, ABEC5 Assembly.." In all honesty that goes over my head. Anything there to justify the "upgrade"?

Only 18,000+ posts? lol, I appreciate the advice!


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## stealle (Aug 31, 2013)

JSWhaler said:


> I run a da 7950 crankset and after everything I've read, I'm sticking with the shimano rings. In addition I've used ceramic bb's before. They may be blingy and all but in reality while pedaling you won't notice much of a difference and they don't last as long. Buy yourself the dura ace bb and be done with it.


I don't thing a dura-ace BB is an option. As I understand it, Specialized comes with their own proprietary "OSBB." From what I've read you can use various adapters for about $30 that are cheap, eventually wear out and don't last. Or you can replace it with a proper $85 Praxis Works BB in order to convert it to accept a Shimano Crank.
CONV BB FOR SHIMANO - Praxis Cycles


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## stealle (Aug 31, 2013)

masont said:


> Also, you said "I'm getting."
> 
> If you haven't bought it yet and you're talking upgrades already, I'd just buy the expert. It's $900 more, but you get a better frame, better brakes, better wheels, a better crank, a better seatpost - if you're already talking upgrades that are going to cost you around $400, why not just buy the bike that has upgrades at those spots anyway?
> 
> Full disclosure: I work at a Specialized dealer, my current road bike is an Allez expert that has the same kit as the Roubaix expert. The SLK crank that comes on it is very good despite the fact that it says FSA on it. The rings are quality, it shifts great, and it's plenty stiff.


masont- I appreciate the advice. I really want the expert. Unfortunately, I'm on a budget. I was going for the Sport 105 model. Then I decided to stretch more than I should for the Comp model. It's hard for me to almost double my original budget. On top of that, I recently discovered that Specialized had a $300 off the 2013 Roubaix last April. I'm hoping for a $300 off sale on the 2014 Roubaix this year to help me out. If that doesn't happen, I'll struggle a bit with this purchase. 

Is the FACT 10r frame really much better than the 8r? I'm mostly interested in endurance riding. Of course I want to go fast, but the main reason I'm going carbon frame is to help with the road vibrations on these horrable chip/seal roads I ride on.


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## masont (Feb 6, 2010)

stealle said:


> masont- I appreciate the advice. I really want the expert. Unfortunately, I'm on a budget. I was going for the Sport 105 model. Then I decided to stretch more than I should for the Comp model. It's hard for me to almost double my original budget. On top of that, I recently discovered that Specialized had a $300 off the 2013 Roubaix last April. I'm hoping for a $300 off sale on the 2014 Roubaix this year to help me out. If that doesn't happen, I'll struggle a bit with this purchase.
> 
> Is the FACT 10r frame really much better than the 8r? I'm mostly interested in endurance riding. Of course I want to go fast, but the main reason I'm going carbon frame is to help with the road vibrations on these horrable chip/seal roads I ride on.


I'm honestly not sure re: the frame. I rode the expert (same frame) last year, but I have yet to throw a leg over the lower end sl4 frame. 

If you're on a budget, stick with the Gossamer that's on there. It isn't sexy, but it works just fine. It was good enough for Cancellara back in 2007, and the new bb30 version ain't any worse. 

www.cyclingnews.com presents the 94th Tour de France


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## Jay Strongbow (May 8, 2010)

stealle said:


> I was going to go with Ultegra 6800, but then *I saw on Praxis website they have a Dura-Ace 7950 crank that is fitted with Praxis ring-set*. I'm not sure which one to go with.


You might want to double check that. Despite showing a picture of a Dura Ace crank arm I'm pretty sure Praxis doesn't actually sell them.


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## Z'mer (Oct 28, 2013)

You can put black shimano 105 chain rings on the gossamer crank, and you'll have a nice shimano shifting hybrid. I own a gossamer, not a fan of the stock rings.
In essence, I think they make an otherwise decent crank horrible.

The gossamer is equivalent to a shimano tiagra 4600 crankset if you consider the crank arms only. The Tiagra has better chainrings.

And cancellara had upgraded chainrings on his gossamer.


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## mannymerc (Nov 19, 2013)

Praxis makes good chainrings and they shift pretty well, but nothing is better than shimano front shifting...


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## Z'mer (Oct 28, 2013)

The shimano 105 black set of two 50/34 compact chainrings costs $61. - 21.+ 40.
just saying...


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## stealle (Aug 31, 2013)

A shimano 105 *11-speed* does not exist. Just replacing the chainrings is a good idea tho. I wonder if Ultegra 6800 chainrings would fit on the stock crank. I'm guesssing no.


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## stealle (Aug 31, 2013)

Jay Strongbow said:


> You might want to double check that. Despite showing a picture of a Dura Ace crank arm I'm pretty sure Praxis doesn't actually sell them.


Ha. Good eye. That made the decision easier. I thought it included the crank since they call it a "DA7950 Integrated Set" but after looking closer, I think your right. It's just a chainring set. Looks like if I do replace the crank, it will be with an Ultegra 6800 and the standard Praxis BB conversion. 

Guys, am I correct that the Praxis BB conversion is the only full BB available (no adapters) in order to use a Shimano crank? I mean, Shimano doesn't make a BB that will fit into a Specialized frame, right?


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## Z'mer (Oct 28, 2013)

stealle said:


> A shimano 105 *11-speed* does not exist. Just replacing the chainrings is a good idea tho. I wonder if Ultegra 6800 chainrings would fit on the stock crank. I'm guesssing no.


The 7950 is not 11 speed either. The cassette is what's different between 10 and 11 speed, not the chainrings. Also the Shimano 11 speed chain is same inner dimension as 10 speed chain, but a little more narrow on the outside only. 
I replaced my FSA Gossamer with a Shimano 6800, and use it on a 10 speed Shimano drivetrain. 
And no, 4 bolt 6800 chainrings do not fit the 5 bolt Gossamer crank. They are interchangeable though, with the Dura-Ace 9000, both a new Shimano standard - 110 mm, 4 bolts. 
On the Dura-Ace models, you have ring pair options from 34 to 55T, all fitting on the same 110mm 4 bolt drive crank. 
Universal Cycles -- Shimano Dura-Ace FC-9000 Double Chainrings 11sp


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## brinox (Jul 30, 2010)

stealle said:


> Ha. Good eye. That made the decision easier. I thought it included the crank since they call it a "DA7950 Integrated Set" but after looking closer, I think your right. It's just a chainring set. Looks like if I do replace the crank, it will be with an Ultegra 6800 and the standard Praxis BB conversion.
> 
> Guys, am I correct that the Praxis BB conversion is the only full BB available (no adapters) in order to use a Shimano crank? I mean, Shimano doesn't make a BB that will fit into a Specialized frame, right?


No, Shimano does not make any BB system that fits into BB30/PF30 or OSBB designs. the Praxis Conversion BB kit is the only worthwhile kit out there that fully encloses the bottom bracket area for a 24mm Shimano spindle (Hollowtech II in Shimano marketing speak). It also moves the bearing to sit outside the BB joint, whereas all other adapters retain the original OSBB or BB30/PF30 bearings where they are.

I have the BB30/PF30 kit on my Diamondback frame and have put close to 3000 miles on it since the middle of last summer. I've *never* had a problem with it, and there's zero creaking or other oddball noises that come from it. Having ridden both a regular PF30 crank design as well as the Praxis PF30 conversion design, I feel slightly more comfortable on the Praxis BB.


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## Tunnelrat81 (Mar 18, 2007)

brinox said:


> No, Shimano does not make any BB system that fits into BB30/PF30 or OSBB designs. *the Praxis Conversion BB kit is the only worthwhile kit out there that fully encloses the bottom bracket area for a 24mm Shimano spindle (Hollowtech II in Shimano marketing speak).* It also moves the bearing to sit outside the BB joint, whereas all other adapters retain the original OSBB or BB30/PF30 bearings where they are.
> 
> I have the BB30/PF30 kit on my Diamondback frame and have put close to 3000 miles on it since the middle of last summer. I've *never* had a problem with it, and there's zero creaking or other oddball noises that come from it. Having ridden both a regular PF30 crank design as well as the Praxis PF30 conversion design, I feel slightly more comfortable on the Praxis BB.


This may be true, but there are other complete BB's that accomplish the same thing. Wheels Mfg. makes an integrated pressed in complete BB for both BB30 and PF30, doing in similar but slightly different way the same thing that the Praxis brand BB does. Problem is there is VERY little information on real world experience with the wheels manufacturing BB set. Lots of commentary on their BB30/PF30 adapters, but not on their complete BBs.

-Jeremy


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## stevem (Oct 7, 2014)

I had Praxis rings to replace a set of FSA chainrings on a 10spd 105, and the shifting improved markedly. When I switched to Ultegra 6800, the crisp excellent shifting became finicky, difficult, and less than 100%. My LBS suggested the issue may be with the rings, so I picked up an Ultegra 6800 compact, and I couldn't be happier. The mechanics rode the bike, and were familiar with the issues as they did the groupset change to 6800. They both ride Di2s, and one of them were offering a trade. Yes -- there's nothing like Shimano.


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