Weight Weenies
* FAQ    * Search    * Trending Topics
* Login   * Register
HOME Listings Blog NEW Galleries NEW FAQ Contact About Impressum
It is currently Sun Feb 19, 2017 6:16 pm

All times are UTC+01:00




Post new topic  Reply to topic  [ 24 posts ]  Go to page 1 2 Next
Author Message
PostPosted: Wed Feb 15, 2017 8:39 pm 
Offline

Joined: Sun Jun 10, 2012 1:11 am
Posts: 894
My cousin gave me a pair of wheels he brought back from Taiwan.

Kinlin XR31T/31RT 20/24H
CN Aero424 spokes
Bitex F13/R13 hub
Conti GP4K2 - 23mm

I'm 68Kg and from dead start sprint on my TMR02, I can feel the sluggish feeling.

Likewise when I'm climbing 8% or higher grades, sitting down I can feel the flex and the wheels rub against the pads. I'm leaving 3mm gap between the pads and brake tracks.

We've checked it out by Mikes Bike and it's trued and spoke tension is good.

Could it be the Bitex hub or something else?

Thanks


Top
   
PostPosted: Wed Feb 15, 2017 8:54 pm 
Offline

Joined: Wed Sep 05, 2007 2:02 pm
Posts: 436
Thin spokes and less than ideal hub geometry.


Top
   
Posted: Wed Feb 15, 2017 8:54 pm 


Top
   
 
PostPosted: Wed Feb 15, 2017 11:32 pm 
Online

Joined: Thu Feb 25, 2016 9:55 pm
Posts: 58
If your wheel rubs in the brakes the spokes are too weak for your rim. Search for the article "debunking wheel stiffness" to learn more. Any sluggish feel is likely just weight or imagination. Even a radially laced rear wheel has minimal deformation due to torsional loads, Jobst Brandts book has some simulation results demonstrating it.

Probably, 20/24 is not a good choice with your chosen spoke+hub combo.


Top
   
PostPosted: Thu Feb 16, 2017 12:26 am 
Offline

Joined: Sun Jun 10, 2012 1:11 am
Posts: 894
in that case, what spokes or hubs choice would pair well with this rim?


Top
   
PostPosted: Thu Feb 16, 2017 12:42 am 
Offline
User avatar

Joined: Wed Jun 08, 2011 6:08 am
Posts: 721
Replace the rear spokes with cn494 if they will fit through the holes. Sapim Race otherwise.


Top
   
PostPosted: Thu Feb 16, 2017 1:42 am 
Offline

Joined: Sun Jun 10, 2012 1:11 am
Posts: 894
How about hub? Should I change to a stronger hub?


Top
   
PostPosted: Thu Feb 16, 2017 3:34 am 
Offline
User avatar

Joined: Wed Jun 08, 2011 6:08 am
Posts: 721
The RAR12 NDS flange to center is 37.7mm, which is good. Certainly not as bad as a DT 240. Your real problem is not enough spokes.


Top
   
PostPosted: Thu Feb 16, 2017 6:17 am 
Offline
in the industry
User avatar

Joined: Wed Jan 19, 2011 11:14 am
Posts: 1557
Location: SYD
what is the spoke tensions? its 2017 unless you weigh 90+ kgs you have more than enough spokes.. also while the bitex hubs are not something I would sell they are actually pretty good hubs.
i think it may not be build that well..

a wheel can be round and true and not well built.. the 2 are not mutually exclusive

_________________
Skunkworks Bikes


Last edited by sugarkane on Thu Feb 16, 2017 1:41 pm, edited 1 time in total.

Top
   
PostPosted: Thu Feb 16, 2017 7:40 am 
Offline

Joined: Sun May 16, 2010 7:28 pm
Posts: 971
Did physics change in the last 5 years that magically changed the material properties of steel spokes? Read the slowtwitch article mentioned above about laterally flexy wheels. I agree with others above, reasonable wide hub, xr31 is a pretty wide and deep rim, which should be pretty sturdy. That leaves the spoke build, which may be insufficient.


Top
   
PostPosted: Thu Feb 16, 2017 1:39 pm 
Offline
in the industry
User avatar

Joined: Wed Jan 19, 2011 11:14 am
Posts: 1557
Location: SYD
those spokes are not ultra light units.. not on the level with the super spoke.. and speaking as some one who builds wheels for actual monies... how well has this wheel been built.............

Image

this is a certain swiss hub laced with X-rays to a certain carbon rim built in house in the bible belt of the USA..

so tension over all is low on the drive side but not that bad.. and on the non drive side its.. well F'ing awfully
so the over all percentage of deviation doest take into account that spokes 23 and 17 are so low that they are not able to be measured..

spokes 1, 11, 15, 19 are the only ones doing a any work thats worth while and 1 is carrying the load of over half the wheel....
what that means is all the other spoke are under load carrying no tension except for the extra special spokes a 23 and 17 which are never at any time carrying any tension.. note this wheel is straight and most true...
this wheel rubs the brake pads, and according to the owner is seriously lacking in stiffness .. rider is in his low 70kgs..

here is the wheel after the tension deviation issues are addressed

Image

wheel now feels amazing and drives under power so well its like a new wheel..

it doesn't take a rocket scientist to see the difference between these different version of the same wheel..
now the top wheel can be built using the 1950s feel method in 20 min after lacing.. the bottom one takes around an hour and a consistent, repeatable tension meter. most wheels built where volume is the key will not be built to such standards..
round and true do not always mean well built..

instead of seeking expert opinions on the internet maybe take the wheel to a gun wheel builder in you area.. if you let me know where you be i may be able to post you in the right direction..

:beerchug:

_________________
Skunkworks Bikes


Top
   
PostPosted: Thu Feb 16, 2017 5:30 pm 
Offline

Joined: Fri Feb 18, 2005 6:50 pm
Posts: 54
Location: Wilmington, DE
addictR1 wrote:
We've checked it out by Mikes Bike and it's trued and spoke tension is good.


As others have noted, 'trued' means nothing. The most true/round wheels I've had my hands on (all machine built wheels) have been the worst as far as even tension goes. I always compromise a bit on my own builds, settling for +/-5% on tension (per my Park TM-1) and letting a little out of true/round go as it's never been an issue for me (especially on my disc wheel builds :)). I have never broken a spoke or had rubbing issues on wheels I've built or wheels that I've reworked (those machine built wheels mentioned above).

So how did 'Mikes Bike' determine that the 'spoke tension is good'?


Top
   
PostPosted: Thu Feb 16, 2017 7:10 pm 
Offline

Joined: Sun Jun 10, 2012 1:11 am
Posts: 894
sugarkane: i'm in San Jose, CA area.

i can't recall what's the exact tension on the spokes.. but Mikes Bike tech mentioned it's very even for the drive side and on the non drive side as well. Definitely much better than the previous Farsport wheels i brought in for them to check and true.


Top
   
PostPosted: Fri Feb 17, 2017 2:49 am 
Offline

Joined: Fri Feb 18, 2005 6:50 pm
Posts: 54
Location: Wilmington, DE
Have you checked the cartridge bearing preload? If the axle is loose in the hub it could be causing all of your issues. Those aren't super lightweight hubs so I just can't see how a properly tension wheel with them would flex like you are describing.


Top
   
PostPosted: Fri Feb 17, 2017 7:49 am 
Offline

Joined: Sun Jun 10, 2012 1:11 am
Posts: 894
joejack951 wrote:
Have you checked the cartridge bearing preload? If the axle is loose in the hub it could be causing all of your issues. Those aren't super lightweight hubs so I just can't see how a properly tension wheel with them would flex like you are describing.


How to check that?


Sent from my iPad using Tapatalk


Top
   
Posted: Fri Feb 17, 2017 7:49 am 


Top
   
 
PostPosted: Fri Feb 17, 2017 8:53 am 
Offline

Joined: Wed Jan 22, 2014 11:48 am
Posts: 1874
Location: Vienna Austria
Sorry, but my guess is that it's your imagination.

* The XR31 ist a very good rim, and the tall, wide profile makes it very stiff. It's also not too light.
* You have an asymmetric rear, so bracing angles are evened out, and the drive side doesn't need to be built with thicker spokes.
* Re build quality: While slightly uneven tension can reduce durability, it has ZERO effect on stiffness. This is not intuitive but has been proven often enough.

Bitex hubs are also quite good, quality and geometry wise.

I'm 75-80kg and can put out decent torque/power, and I run XR22 rims - which are shallower and lighter - on similar Novatec hubs without problems. I also have similar spokes, only heavier ones on the drive side, but I don't have an asymmetric rear rim.

IMO this is an excellent all-round wheelset that should work really well even for riders quite a bit heavier than you.


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 24 posts ]  Go to page 1 2 Next

   Similar Topics   Author   Replies   Views   Last post 
There are no new unread posts for this topic. Wheel Question: Keep or Sell

in Cyclocross / Gravel / Touring

FIJIGabe

3

333

Wed Aug 24, 2016 10:24 pm

FIJIGabe View the latest post

There are no new unread posts for this topic. Campa Bora 50 wheel 2013 question

in Everything wheels

poppiholla

4

311

Thu May 26, 2016 1:31 am

fogman View the latest post

There are no new unread posts for this topic. Corima Mcc'S+' Wheel vs Campagnolo Bora Ultra Wheel

in Everything wheels

PARKJAEBUM

12

1245

Thu Jan 12, 2017 5:41 pm

dj97223 View the latest post

There are no new unread posts for this topic. Was Chinese Carbon Wheel Advice now, recommend me some wheel

in Everything wheels

Ste_S

11

2477

Sun Mar 27, 2016 8:11 pm

wheelsONfire View the latest post

There are no new unread posts for this topic. 26 vs 27.5 vs 29 wheel mtb.

[ Go to page: 1 2 ]

in MTB

skiezo

23

1963

Mon Feb 06, 2017 5:50 pm

Jaker View the latest post


All times are UTC+01:00


Who is online

Users browsing this forum: shk1 and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited