Hub recommendation for new wheelset

Discuss light weight issues concerning road bikes & parts.
User avatar
ergott
Posts: 2763
Joined: Tue Apr 18, 2006 3:03 am
Location: Islip, NY
Contact:

by ergott

uraz wrote:
I'm not changing gears under load if I don't have to, and this is all you need to disengage a freewheel (even when you don't stop pedalling). Any drop in power/cadence is sufficient to feel how 18T ratchet works.


Doesn't have to be zero power when shifting. Even dropping down to 100w or so is more than fine for shifting and no way freewheel is disengaging no matter what hub.

Sent from my SM-G950U using Tapatalk

BdaGhisallo
Posts: 1889
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

ergott wrote:
BdaGhisallo wrote:
bm0p700f wrote:Yes thicker spokes help but if you had used a hub with better geometry you could have used thinner spokes.


I guess you didn't read my comment too closely. I have a set built around a hub with better geometry and thinner spokes and they are not as stiff as the set built around the hub with less optimal geo and thicker spokes.
The Sapim CX-Sprint is the same gauge as the Sapim Race. Similar comparison between DT Aero Comp and DT Competition.

Sent from my SM-G950U using Tapatalk


I see different weights posted for the two:

Wheelbuilder.com shows 64 spokes of 260mm length weighing the following:

Race DB 380g
CX Sprint 334g

And Fairwheel quotes the weight for individual spokes and I assume they are using a standard spoke length to quote weights:

Race DB 5.9 - 6.5g per spoke
Cx Sprint 5.4 - 6.2g per spoke


That said, I cannot even find the CX Sprint on Sapim's website so who knows for sure.

uraz
Posts: 81
Joined: Thu Dec 12, 2013 9:48 pm

by uraz

ergott wrote:Doesn't have to be zero power when shifting. Even dropping down to 100w or so is more than fine for shifting and no way freewheel is disengaging no matter what hub.


To lower power input (doesn't matter how much 20, 50 100%) you will have to lower cadence. This means that freehub is now rotating with different speed than hub shell thus pawls/ratchets are disengaged. Shifts are quick and smooth so you probably don't notice it (unless your hub is using 18T ratchet).

I'm always choosing hubs that have less than 8 degree engagement and I'm used to them. When from time to time I have a "pleasure" to ride on a bike with for example dt 240s using 18T ratchet I fill like something is not all right. Maybe if someone is used to slow engagement it's not driving him crazy. Who knows...

User avatar
Lelandjt
Posts: 419
Joined: Tue Jan 19, 2016 7:10 am

by Lelandjt

uraz wrote:
ergott wrote:Doesn't have to be zero power when shifting. Even dropping down to 100w or so is more than fine for shifting and no way freewheel is disengaging no matter what hub.


To lower power input (doesn't matter how much 20, 50 100%) you will have to lower cadence. This means that freehub is now rotating with different speed than hub shell thus pawls/ratchets are disengaged. Shifts are quick and smooth so you probably don't notice it (unless your hub is using 18T ratchet).

I'm always choosing hubs that have less than 8 degree engagement and I'm used to them. When from time to time I have a "pleasure" to ride on a bike with for example dt 240s using 18T ratchet I fill like something is not all right. Maybe if someone is used to slow engagement it's not driving him crazy. Who knows...

First bolded...WTF?
Second bolded....yes, I use 18pt on all my MTBs cuz it's quieter and stronger.

BdaGhisallo
Posts: 1889
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

Lelandjt wrote:
uraz wrote:
ergott wrote:Doesn't have to be zero power when shifting. Even dropping down to 100w or so is more than fine for shifting and no way freewheel is disengaging no matter what hub.


To lower power input (doesn't matter how much 20, 50 100%) you will have to lower cadence. This means that freehub is now rotating with different speed than hub shell thus pawls/ratchets are disengaged. Shifts are quick and smooth so you probably don't notice it (unless your hub is using 18T ratchet).

I'm always choosing hubs that have less than 8 degree engagement and I'm used to them. When from time to time I have a "pleasure" to ride on a bike with for example dt 240s using 18T ratchet I fill like something is not all right. Maybe if someone is used to slow engagement it's not driving him crazy. Who knows...

First bolded...WTF?
Second bolded....yes, I use 18pt on all my MTBs cuz it's quieter and stronger.


I think the only thing we can reasonably conclude is that we all like what we like... and there's nothing wrong with that. We are all impassioned boosters of the gear we like and that's part of the fun of this sport.

18T - 36T - 54T ? Go your own way and be happy.

Hexsense
Posts: 417
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

uraz wrote:
ergott wrote:Doesn't have to be zero power when shifting. Even dropping down to 100w or so is more than fine for shifting and no way freewheel is disengaging no matter what hub.


To lower power input (doesn't matter how much 20, 50 100%) you will have to lower cadence. This means that freehub is now rotating with different speed than hub shell thus pawls/ratchets are disengaged. Shifts are quick and smooth so you probably don't notice it (unless your hub is using 18T ratchet).


Are you that incapable in coordinating your leg neuromuscular to the point that you can't do 100 watts while still engaging the freehub?
Yes, Cadence will slow down. but slow down in sync with hub rotation speed and inertia.
Power=Torque x Cadence. Just remove most if not all the Torque but still sync Cadence with freehub rotation speed, is it that hard?
if your crank spin slower than free wheel, you are producing 0 watts or less to the rear wheel (maybe some watts from your leg but it doesn't transfer to the wheel since it can't even match hub rotation speed). Not positive numbers.
I bet someone very coordinated can do 5watts or even 0.1 watts while not disengage from freewheels.
Last edited by Hexsense on Mon Nov 27, 2017 6:55 pm, edited 1 time in total.

User avatar
ergott
Posts: 2763
Joined: Tue Apr 18, 2006 3:03 am
Location: Islip, NY
Contact:

by ergott

uraz wrote:
To lower power input (doesn't matter how much 20, 50 100%) you will have to lower cadence. This means that freehub is now rotating with different speed than hub shell thus pawls/ratchets are disengaged. Shifts are quick and smooth so you probably don't notice it (unless your hub is using 18T ratchet).



Reducing pressure on the pedals (lowering power output) isn’t the same as reducing cadence. In other words, pedaling at 300w and dropping down to 100w you are still pedaling with power to the cranks. The rear wheel will not freewheel and you can shift. It’s the mark of having smooth power output and control over your pedal stroke.



Sent from my iPad using Tapatalk

User avatar
ergott
Posts: 2763
Joined: Tue Apr 18, 2006 3:03 am
Location: Islip, NY
Contact:

by ergott

BdaGhisallo wrote:I see different weights posted for the two:



Sorry, there was also the CX-Speed I’m thinking of which was the same weight as the Race. I had to file the spoke holes to get them to fit.

Sprints are indeed lighter and more in line with a 2.0/1.7/2.0mm spoke. DT Aero Comps too.




Sent from my iPad using Tapatalk

BdaGhisallo
Posts: 1889
Joined: Wed Mar 17, 2004 1:38 pm

by BdaGhisallo

ergott wrote:
BdaGhisallo wrote:I see different weights posted for the two:



Sorry, there was also the CX-Speed I’m thinking of which was the same weight as the Race. I had to file the spoke holes to get them to fit.

Sprints are indeed lighter and more in line with a 2.0/1.7/2.0mm spoke. DT Aero Comps too.




Sent from my iPad using Tapatalk


Cheers Eric.

uraz
Posts: 81
Joined: Thu Dec 12, 2013 9:48 pm

by uraz

ergott wrote:Reducing pressure on the pedals (lowering power output) isn’t the same as reducing cadence. In other words, pedaling at 300w and dropping down to 100w you are still pedaling with power to the cranks. The rear wheel will not freewheel and you can shift. It’s the mark of having smooth power output and control over your pedal stroke.

Despite it's possible to maintain some level of pressure on pedals during the period of power droppage and shift smoothly (especially on flat terrain) without disconnecting freehub it is not always the case. On many occasions freewheel will disengage.

Hexsense
Posts: 417
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

uraz wrote:
ergott wrote:Reducing pressure on the pedals (lowering power output) isn’t the same as reducing cadence. In other words, pedaling at 300w and dropping down to 100w you are still pedaling with power to the cranks. The rear wheel will not freewheel and you can shift. It’s the mark of having smooth power output and control over your pedal stroke.

Despite it's possible to maintain some level of pressure on pedals during the period of power droppage and shift smoothly (especially on flat terrain) without disconnecting freehub it is not always the case. On many occasions freewheel will disengage.

it's only disengage if you apply 0 watts or less to the rear wheel for any period of time.
think through this, if your leg is not on the crank, chain and bb has no friction but the free hub mechanism has, what happen to the crank when hub turn? the crank rotate follow the hub! That's zero watts applied but crank still turn with the wheel. Obviously chain and bb have some friction and your leg is there preventing it from turning so this doesn't really happen but i hope you get the idea that it's easy ... i mean, very easy... to ease off the power but not disengage rear hub. (you have range of 5-100 watts, any power in this range are mild and yet not disengaging the hub , for example.)

bm0p700f
in the industry
Posts: 3653
Joined: Sat May 12, 2012 7:25 pm
Location: Glermsford, Suffolk U.K
Contact:

by bm0p700f

It also depends on how improved the geometry of the new hub compared to the dt hub. The hub I use commonly has 55mm flange seperation. A white in t11 for comparison has 51mm flange seperation. If the nds flange is moved out far enough then that can make up for the thinner spokes. Tension balance drops though. It's a balancing act as that combination requires radially and laterally stiff rims.

Post Reply
  • Similar Topics
    Replies
    Views
    Last post