Fulcrum Zero Nite 17 don't support 23mm tyres???

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JBC2
Posts: 14
Joined: Sat Jan 13, 2018 4:51 pm

by JBC2

Don't usually read the manual but glad I did before fitting the tyres and invalidating the return option.

The manual says the 17 only support 25mm upwards. Not taking a chance with kids racing on unsupported rim/tyre combo.

So is this a new standard rim width start at support for 25mm and upwards?

Issue is gear restriction based on metres of development meaning that we are usually restricted to 23mm tyres.

Does anyone know how I accurately work out this value without fitting the 25mm tyre to the wheel?

Else I am looking something different!

Many thanks

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TonyM
Posts: 2005
Joined: Thu Jan 22, 2015 4:11 pm

by TonyM

The "theory" from ETRTO says 17C with tires as from 25mm:

Image

by Weenie


JBC2
Posts: 14
Joined: Sat Jan 13, 2018 4:51 pm

by JBC2

Yes as per the manual.

Wow, that is surely going to catch anyone racing under the age of 18....

Unless 25mm can be made to go under the rollout limit.

AJS914
Posts: 1950
Joined: Tue Jan 28, 2014 6:52 pm

by AJS914

Most 23mm tires out there will measure 25mm especially on a wider rim.

Hexsense
Posts: 370
Joined: Wed Dec 30, 2015 12:41 am

by Hexsense

TonyM wrote:
Tue Jan 30, 2018 10:21 pm
The "theory" from ETRTO says 17C with tires as from 25mm:
this "theory" need to be updated.
it was writen in the age of lousy tolerance alloy rim (no tight tubeless compatible hook)
and no kevlar or advanced material tire bead.

HED officially encourage riders to use 23c on their 20mm inner width rim. Roval, Enve and other brands also have similar statement.
Mavic once against breaking the "theory". but now they said it's fine to do so with their new tubeless system.

Alumen
Posts: 87
Joined: Tue Aug 18, 2015 1:47 pm

by Alumen

23mm on 17C is just fine... I use this combo on my front wheel and they flow nicely over into the actual rim which most likely will give some aero benefits.

Like mentioned, they are measured as 25mm.
CAAD 10 2015

beeatnik
Posts: 328
Joined: Fri Jan 25, 2013 7:26 pm

by beeatnik

Use Veloflex 25mm clinchers. Size marking fades after a few rides

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Beaver
Posts: 346
Joined: Wed Aug 18, 2004 6:06 pm
Location: Lower Saxony - Germany

by Beaver

The chart above is outdated, a new one is in the making. Mavic sells 19C rims with 25mm tires now... I am running 25mm tires on 21C rims for 18 months now - don't worry, 23mm on 17C is fine.

by Weenie


morganb
Posts: 514
Joined: Wed Mar 15, 2017 5:30 pm

by morganb

Hexsense wrote:
Wed Jan 31, 2018 7:27 pm
TonyM wrote:
Tue Jan 30, 2018 10:21 pm
The "theory" from ETRTO says 17C with tires as from 25mm:
this "theory" need to be updated.
it was writen in the age of lousy tolerance alloy rim (no tight tubeless compatible hook)
and no kevlar or advanced material tire bead.

HED officially encourage riders to use 23c on their 20mm inner width rim. Roval, Enve and other brands also have similar statement.
Mavic once against breaking the "theory". but now they said it's fine to do so with their new tubeless system.
Roval/Specialized went so far as to spec from the factory a 22mm tire on a 21mm internal rim on the Venge, not sure if they still are but the first rim brake models came like that.

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