SkyPivot——A superlight carbon crankset from China

Discuss light weight issues concerning road bikes & parts.
alanyu
Posts: 472
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

What's the weight of the chainring? It looks like the AbsoluteBlack one which is heavier than DA one

cajer
Posts: 215
Joined: Sun Jul 14, 2013 1:26 am

by cajer

Have you thought of an aero chainring that blends in to fit perfect with the powemeter to form one aero shape?

by Weenie


MichaelB
Posts: 734
Joined: Tue Apr 22, 2008 4:31 am

by MichaelB

philipeleven wrote:
Mon Oct 28, 2019 8:49 pm
And...designing gravel frame these days :)
Some elements from the Volagi Liscio there.

Looks good

philipeleven
Posts: 74
Joined: Mon Sep 23, 2019 2:01 pm

by philipeleven

alanyu wrote:
Mon Oct 28, 2019 10:44 pm
What's the weight of the chainring? It looks like the AbsoluteBlack one which is heavier than DA one
140 to160grams depands on size

philipeleven
Posts: 74
Joined: Mon Sep 23, 2019 2:01 pm

by philipeleven

cajer wrote:
Mon Oct 28, 2019 11:08 pm
Have you thought of an aero chainring that blends in to fit perfect with the powemeter to form one aero shape?
something like aero cover will be good too... those shape is for creating a smooth surface on the back side like the shimano 9100 chainrings, which is good for shifting performance.

User avatar
Klaster_1
Posts: 923
Joined: Mon Aug 15, 2016 10:25 am
Location: Russia, Saint Petersburg

by Klaster_1

Just asked Digirit is they were going to make a CF DM chainring for the crank:
For the new direct mount, we can make it. In fact, we had made it. Please refer photo attached.
Their 38t DM chainrings are ~75g, so a couple of grams heavier than a spider/bolts/FibreLyte. And ~30g more than a Clavicula SE in similar setup.
Attachments
directMount.jpg

alanyu
Posts: 472
Joined: Thu Jun 06, 2019 1:10 pm

by alanyu

philipeleven wrote:
Tue Oct 29, 2019 4:52 am
alanyu wrote:
Mon Oct 28, 2019 10:44 pm
What's the weight of the chainring? It looks like the AbsoluteBlack one which is heavier than DA one
140 to160grams depands on size
Heavier than DA's.

Francois_Viviers
Posts: 198
Joined: Sat Oct 25, 2003 7:12 pm

by Francois_Viviers

That powermeter looks different to the Axo, any more info on it?

kode54
Posts: 1843
Joined: Tue May 23, 2006 9:39 pm

by kode54

excellent. I'm in for a set.
philipeleven wrote:
Mon Oct 28, 2019 9:40 pm
kode54 wrote:
Mon Oct 28, 2019 9:10 pm
philipeleven wrote:
Mon Oct 28, 2019 8:39 pm
Since the beta version cranks were sent out for testing, and we are waiting for the next batch of products (about 40pairs finish in the next month, and, will come with black label), it seems nothing important to update :)

I'm testing PM these days, finish designing the serperated chainring for PM, and started to produce them. New PM and chainrings will be ready in next month too.

I think next major update will be test articles come out from medias, plz stay tune for it :)
Black label version looks good. 1x and 2x spiders? Matte finish?
making 2X rings...there are soooo many spec of 1X so it won't be made until mass production(maybe early next year).
black label version come in matte finish.
- Factor 02 Disc + DA9170 + Enve 4.5AR CK CL hubs
- Moots Vamoots Disc RSL Titanium + DA9170 + Enve 3.4AR CK CL hubs
- Parlee Chebacco + DA9170 + Enve G23 CK CL hubs
- Allied Able + DA9170 + Enve G27 CK CL hubs

philipeleven
Posts: 74
Joined: Mon Sep 23, 2019 2:01 pm

by philipeleven

Klaster_1 wrote:
Tue Oct 29, 2019 7:01 am
Just asked Digirit is they were going to make a CF DM chainring for the crank:
For the new direct mount, we can make it. In fact, we had made it. Please refer photo attached.
Their 38t DM chainrings are ~75g, so a couple of grams heavier than a spider/bolts/FibreLyte. And ~30g more than a Clavicula SE in similar setup.
38t+spider equals 73g... and about 6g for bolts. but it will be way cheaper than carbon and more durable...
Attachments
微信图片_20191029225117.png

philipeleven
Posts: 74
Joined: Mon Sep 23, 2019 2:01 pm

by philipeleven

alanyu wrote:
Tue Oct 29, 2019 8:44 am
philipeleven wrote:
Tue Oct 29, 2019 4:52 am
alanyu wrote:
Mon Oct 28, 2019 10:44 pm
What's the weight of the chainring? It looks like the AbsoluteBlack one which is heavier than DA one
140 to160grams depands on size
Heavier than DA's.
Having difficulty to design a good looking 4 bolt lightweight chainring... use a similiar style as extralite just looks terrible. and there are shifting performance related too.

So I just gave up making superlight chainring for 4 bolt spider now. anyone needs shave down weight could just go for 5 bolt spider(39g), with extralite chainrings.
Attachments
微信图片_20191029225638.png
微信图片_20191029230310.png

Hexsense
Posts: 1221
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

philipeleven wrote:
Mon Oct 28, 2019 8:49 pm
And...designing gravel frame these days :)
*comment below is offtopic and has nothing to do with the crank, anyone that only interested with the crank can skip*

Please don't be another bike that has good geometry in medium size and up.
And utterly slow handling (high trail number) in S and XS due to slack head tube angle pair with inappropriate fork rake that borrow from larger sizes.
Making the matter worse, Gravel bike tends to have tall stack so i have to down size even further than my road bike which also shorter in length and negate the longer wheelbase of gravel bike that i supposed to get...

I wonder if two fork for two different size range (XXS to SM, and M to XXL) is so expensive to the point that most Chinese open mold manufacturers don't bother offering it? They can offer loads of models in many configuration, be it disc or non disc, but don't bother making dedicate fork with appropriate fork rake for small sizes...

philipeleven
Posts: 74
Joined: Mon Sep 23, 2019 2:01 pm

by philipeleven

Hexsense wrote:
Tue Oct 29, 2019 5:15 pm
philipeleven wrote:
Mon Oct 28, 2019 8:49 pm
And...designing gravel frame these days :)
*comment below is offtopic and has nothing to do with the crank, anyone that only interested with the crank can skip*

Please don't be another bike that has good geometry in medium size and up.
And utterly slow handling (high trail number) in S and XS due to slack head tube angle pair with inappropriate fork rake that borrow from larger sizes.
Making the matter worse, Gravel bike tends to have tall stack so i have to down size even further than my road bike which also shorter in length and negate the longer wheelbase of gravel bike that i supposed to get...

I wonder if two fork for two different size range (XXS to SM, and M to XXL) is so expensive to the point that most Chinese open mold manufacturers don't bother offering it? They can offer loads of models in many configuration, be it disc or non disc, but don't bother making dedicate fork with appropriate fork rake for small sizes...

It's simply because draftsmen in China factories have neither ability nor authority to determine frame geometry. They only able to copy geometries from famous brands, usually are cannondale, cervelo and specialized. And they definately don't know the effect of fork rake because they usually don't ride a lot(busy Chinese factories...)
So since they don't understand it, they won't design two or more forks for one frame, unless the customers asked for it. When I worked in a bicycle company 4 years ago, I have to explain again and again why I design a geometry, why it's better for eastern asian people. It is just tiresome. Many won't even bother to try that.

So this gravel frame is a side job I'm doing to design frames for a friendly factory. A long reach geometry was applied on it( like 415mm reach on a M size frame, instead of about 380-385mm), just like the new BMC URS gravel bike. But not like the BMC's unify headtube angle( creating a super long wheel distance in large frames...), I'm going to slightly adjust head angle in different frame size, so as the fork rake.

The picture I uploaded is just a M size for making a geometry baseline. It needs to be produced, field tested, and adjust geometry detail after that. Not until then, the fork rake won't be determine finally.
Last edited by philipeleven on Tue Oct 29, 2019 8:10 pm, edited 1 time in total.

Hexsense
Posts: 1221
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

philipeleven wrote:
Tue Oct 29, 2019 6:10 pm

It's simply because draftsmen in China factories don't have neither ability nor authority to determine frame geometry.

So this gravel frame is a side job I'm doing to design frames for a friendly factory. A long reach geometry was applied on it( like 415mm reach on a M size frame, instead of about 380-385mm), just like the new BMC URS gravel bike.

The picture I uploaded is just a M size for making a geometry baseline. It needs to be produced, field tested, and adjust geometry detail after that. Not until then, the fork rake won't be determine finally.
Dope, Sign me interested in your gravel frameset!

I'm looking to buy gravel frameset in the future, however, my requirement is not answered by many manufacturers, the list includes:
-Stack of no more than 532mm. Preferably around 525mm. Most manufacturers has around 540mm of stack on their smallest size..
-bb drop of no more than 69mm, so that i still can use 650b wheelset with moderate tire size (like 40mm) with appropriate ground clearance (don't need much, i use 165mm crank so it is already hard to hit the ground).
-Moderate, appropriate trail value (on small frame size). For gravel bike, a bit higher is fine for extra stability.
-Not too short in length, longer is better so i don't have to use 120mm+ stem.

User avatar
Beaver
Posts: 788
Joined: Wed Aug 18, 2004 6:06 pm

by Beaver

Looks very interesting. What would be the weight for a 172,5mm/BB386/110BCD 5-bolt spider set? And what ISO and EN testing will you do?

Letting having it checked here (or another indepedant facilitly) would be great and help build trust in the product: https://www.efbe.de/

by Weenie


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