$500...What crank arm set?

Discuss light weight issues concerning road bikes & parts.
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2ndgen
Posts: 617
Joined: Mon Jul 05, 2010 5:18 pm

by 2ndgen

davej35 wrote:DA 7900 is exactly good choice if you're looking for a combination of lightweight and durability.


I'm seeing a lot of love for the 7900 and I could see where it'd be stiffer than what I'm riding now.
Weight difference would only be 15g as far as I know when compared to my current custom set-up
(Ultegra SL Crank/Praxis Clover Rings/Far & Near Bolts/Dura-Ace 7800 BB/762g) according to WW listings.
I think only a set of Hollowgram crank w/my rings would be significantly lighter.

Maybe someone can confirm these numbers for me:
527g Ultegra SL Crank 172.5 (according to Realweights Listing)
127g Praxis 53/39 Chainrings (on my scales)
010g Far & Near Chainring Bolts
098g Dura-Ace 7800 BB
762g

According to CC, the 7900 crankset is 674g + 88g for the BB = 762g :faint:
(WW listing has the 7900 @ 747g?)

Am I missing something when weighing my crankset?
That can't be right.

by Weenie


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2ndgen
Posts: 617
Joined: Mon Jul 05, 2010 5:18 pm

by 2ndgen

prendrefeu wrote:
2ndgen wrote:Hopefully, one day, someone will actually make a non-BB30 adapter for a Hollowgram.


It would require a custom spindle as well, as the lengths & location of bearings will be different. The diameter of the spindle isn't an issue however, just the length.


There's probably not enough demand for it to ever really happen. :cry:

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Rick
Posts: 2035
Joined: Sat Aug 29, 2009 4:30 pm

by Rick

IMO the DA 7800 crank is already the most elegant and best-functioning of all time.
So if you have to have carbon, go DA 7800 carbon:

Image

Raiju
Posts: 9
Joined: Sat Feb 18, 2012 11:53 am

by Raiju

http://www.rotorbike.com/nueva/holandes/bsa30.htm

This is a BSA to BB30 conversion bracket it allows you to use a bb30 crank like cannondales Hollowgram SI crank in a normal BSA threaded frame.

Or you could use a normal rotor 3d crank in your BB. Very light, extremely stiff.

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2ndgen
Posts: 617
Joined: Mon Jul 05, 2010 5:18 pm

by 2ndgen

Rick wrote:IMO the DA 7800 crank is already the most elegant and best-functioning of all time.
So if you have to have carbon, go DA 7800 carbon:

Image


I'd love a carbon 7800, but I had problems just finding the Yumeya rings on it.
Found one, but Damn! $945.!

redoaker
Posts: 84
Joined: Sat Jun 27, 2009 10:20 pm

by redoaker

2ndgen wrote:Hopefully, one day, someone will actually make a non-BB30 adapter for a Hollowgram.


2ndgen, W Weenie member "STARNUT' is a Hollowgram ninja. He has a bike shop;
http://superleggeracycling.com/

He posted a Thread about (2) yrs back showing how he fits Hollowgrams into conventional threaded bottom bracket shells.
It CAN be done and he does it.

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2ndgen
Posts: 617
Joined: Mon Jul 05, 2010 5:18 pm

by 2ndgen

redoaker wrote:
2ndgen wrote:Hopefully, one day, someone will actually make a non-BB30 adapter for a Hollowgram.


2ndgen, W Weenie member "STARNUT' is a Hollowgram ninja. He has a bike shop;
http://superleggeracycling.com/" onclick="window.open(this.href);return false;

He posted a Thread about (2) yrs back showing how he fits Hollowgrams into conventional threaded bottom bracket shells.
It CAN be done and he does it.


I remember, I bumped up my thread, but I guess he hasn't been on WW lately.
I'll reach out to him directly and see what can be done.

On another note, I'm now thinking Zipp Vuma (complete replacement).

Raiju
Posts: 9
Joined: Sat Feb 18, 2012 11:53 am

by Raiju

I don't get it: Rotor makes every bb adaptor for every way around. So if you just look at Rotor bike. Order the right BB for your conversion and you are done. Why bother a guy while the anwser is already given?

hasbeen
Posts: 556
Joined: Tue Feb 07, 2012 7:17 pm

by hasbeen

iirc, you will need a wider spindle to make a hollowgram work which isnt all that easy to find and makes the q-factor quite a bit wider.
Casati Vola SLi and Dolan Preffisio
viewtopic.php?f=10&t=108931" onclick="window.open(this.href);return false;"
btompkins0112 wrote:
It has the H2 geo......one step racier than a hybrid bike

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ProfessorChaos
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Joined: Tue Dec 20, 2011 3:10 am

by ProfessorChaos

Raiju wrote:I don't get it: Rotor makes every bb adaptor for every way around. So if you just look at Rotor bike. Order the right BB for your conversion and you are done. Why bother a guy while the anwser is already given?


The BSA 30 Rotor adapter doesn't work with BB30 cranks. The spacing is off. I vote go Lightning, or Vuma Quad. I have a KCNC, and I've had lots of issues with it. Maybe the new version is better. Rotor won't save much weight at all. Vuma Quads are all over ebay around $500. That is probably your best bet.

AptosBigRing
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Joined: Mon Apr 04, 2011 9:59 pm
Location: Santa Cruz, CA
Contact:

by AptosBigRing

Hi all,
Just was reading the thread and saw all the chat on Conversion BB's and such and wanted to chime in.
We just launched our new BB30/PF30 Conversion BB for Shimano cranks.

I know some of you are riding our cold forged rings, but have a look here.
We wanted to make a really solid conversion BB so that people could run their Di2/XTR/XT or any 24mm standard Shimano cranks on their frames that happen to be either BB30 or PF30. Thought you might be interested.

http://praxiscycles.com/pages/bb30-conversion" onclick="window.open(this.href);return false;

Adam @ Praxis Works
Praxis Works
Manufacturer
Santa Cruz, CA
www.praxis-works.com

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2ndgen
Posts: 617
Joined: Mon Jul 05, 2010 5:18 pm

by 2ndgen

:lol:

Hey Adam! I remember the first time I saw this on the site,
I got all excited thinking it was the other way around;
Conversion kits to run BB30 cranksets on non-BB30 frames!

Then I figured it all out...if that happens, then I can re-use my
Praxis rings and won't buy another set to replace the rings on
a Hollowgram! It's a conspiracy to make me buy another set!

I kid! I kid! :mrgreen:

On another note...
Lovin' my Clover set. Just slapped a KMC X10SL Black DLC Chain.
I was concerned about compatibility, but FYI, it's smooth. Phew!

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ProfessorChaos
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by ProfessorChaos

Just go with a Lightning in a standard 130bcd, and keep your Praxis rings.

rruff
Shop Owner
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Location: Alto, NM

by rruff

ProfessorChaos wrote:I have a KCNC, and I've had lots of issues with it.


What exactly?

by Weenie


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ProfessorChaos
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by ProfessorChaos

rruff wrote:
ProfessorChaos wrote:I have a KCNC, and I've had lots of issues with it.


What exactly?


Well, first I had issues with creaking. I isolated it to the spider. It was coming loose. I tightened it several times, and then eventually the nut stripped out. Fairwheel Bikes was my savior. They replaced the spider, and the nut for free. I then put it on my cx bike as a 1x10, and then eventually SS. I hadn't had any issues for quite some time. Then this fall, I lent it to a friend to try cross racing, and while leading the race, he was climbing a hill, and the spider cracked, and folded over ending his race day. This shocked me. I knew the spider flexed quite a bit so I put a stainless steel Surly chainring on in hopes of less flex. Fairwheel again came to the rescue fixing it well out of any warranty period. Those guys rock. It was a standard 130bcd before. This time I had them put a compact spider on it. I am hoping it holds up better now, being the arms of the spider are shorter I hope they will hold up better. I have not tested it yet however. I haven't decided, but I am contemplating putting it onto my 5200 for next year.

That being said. I have a Lightning on my S2, and it has been flawless as long as I run good bearings in the BB cups. The spider is silent, and much stiffer. Again my KCNC was the older version, and they did redesign the spiders on the new cranks, and they may hold up better.

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