Bora Clinchers; run 23s or 25s?

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fishyskawa
Posts: 46
Joined: Tue May 04, 2010 1:02 am

by fishyskawa

According to Campagnolo you shouldn't run smaller than a 25 on the rim due to ETRTO C17 specifications.

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Denavelo
Posts: 437
Joined: Wed Apr 08, 2009 8:01 pm

by Denavelo

You bought wide clinchers.. Why would you want to run a 23c tire? If you can fit a 28c, run that. The benefit of a wide clincher in my opinion is to run 25c and larger tires. Run them at low PSI and enjoy the smile on your face. I keep Veloflex 25c masters on my wide wheels. My Speedvagen can fit a 30c maybe, so I'm wanting to try to fit a 28c which will plump up to a 30c on a 25mm wide rim.

I found that running 23c tires on 24-26mm wide rims, exposes the rim more to the ground. You can look and see more carbon than tire with a 23c on a wide rim. RUN WIDE TIRES!

Do race cars run narrow tires or wide tires? A Porsche GT3 comes stock with meat in the rear for traction and acceleration. Do the same on your bike if you can fit the tires in your fork and rear stays.
Rob English "Mudfoot" 29er | Focus Izalco Max | Firefly #194 Stainless XCR | Firefly #277 | Neilpryde Bura SL 11.9 | Crust Evasion Lite

fogman
Posts: 1067
Joined: Fri Oct 30, 2009 10:36 pm

by fogman

I purchased some various clinchers from different manufacturers to see how they measure on my Bora One 35 clincher rims with the 24.2mm wide brake track. Pumped to 100psi. Here are the results:

Conti GP4000S II (23c) = 25.4mm
Conti GP4000S II (25c) = 26.7mm
Vredestein Senso (25c) = 25.4mm
Schwalbe One (25c) = 26.2mm
It's all downhill from here, except for the uphills.

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strobbekoen
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Location: BELGIUM

by strobbekoen

My experience as well.
Conti 25 measure close to 27 with calipers.
Vittoria Rubino Pro in 28mm measure slightly less, more like 26.5. go figure :)
So it depends on the specific tire whether you want to run 23 or 25

cmcdonnell
Posts: 278
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

I thought the idea was to run a tyre that has a similar inflated width to the rim width, so a 23 mm would surely be best, particularly as it will come up a similar width to a 25 mm on a normal narrow rim. This is confusing as Zipp recommend 21 or 23 mm tyres on their wheels but according to otehr charts a 25 mm should be the minimum on a 17C rim.
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

fogman
Posts: 1067
Joined: Fri Oct 30, 2009 10:36 pm

by fogman

I asked Campagnolo this question and they said to go by the ETRTO chart.
ImageUploadedByTapatalk1438734443.867634.jpg

I am using the Vredestein Fortezza Senso 700 x 25c which seems to be the narrowest 25c tire I have found so far.
It's all downhill from here, except for the uphills.

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arizonahalfnhalf
Posts: 214
Joined: Mon Jul 27, 2015 9:47 pm

by arizonahalfnhalf

Denavelo wrote:You bought wide clinchers.. Why would you want to run a 23c tire? If you can fit a 28c, run that. The benefit of a wide clincher in my opinion is to run 25c and larger tires. Run them at low PSI and enjoy the smile on your face. I keep Veloflex 25c masters on my wide wheels. My Speedvagen can fit a 30c maybe, so I'm wanting to try to fit a 28c which will plump up to a 30c on a 25mm wide rim.

I found that running 23c tires on 24-26mm wide rims, exposes the rim more to the ground. You can look and see more carbon than tire with a 23c on a wide rim. RUN WIDE TIRES!

Do race cars run narrow tires or wide tires? A Porsche GT3 comes stock with meat in the rear for traction and acceleration. Do the same on your bike if you can fit the tires in your fork and rear stays.


I don't disagree, but the thing is though... as people are saying here, the tire's measurement doesn't always match how its labeled. So you can't just go on that. If you measure those Veloflex Master 25's (which I ride too), you'll see they barely hit 25mm when inflated on a wide rim, even after a few weeks of riding when the tire is stretched out. My "23mm" conti GP4000S's actually measure wider..

As a suggestion though, check out the Challenge Strada Open 25mm (not the "Strada" Model, haven't tried that one). It comes out to about 29mm when inflated on my wide clincher rims. What I like about it is that it is a nice 300tpi tire, much like the Veloflex Master, but it has a lot more meat, a bit taller of a sidewall too. Sure, its heavier, but its supple and made much like the Master so it doesn't feel like mush, but makes even the master feel harsh.

cmcdonnell
Posts: 278
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

Looking at both Zipp and Hed whose new rims are wider than the new bora's (I think), they recommend 23 mm tyres, clearly contrary to the chart above. They also say that 25 mm tyres are only faster than 23 mm when pumped up o an equivalent pressure.

I received my new Bora Ultra 50's yesterday and put on the only tyres I had spare which were Vittoria Open Corsa Evo's (circa 2007) and they fit really well and measured 25.1 mm and seemed to blend into the rims very well. The looked an identical width to the Conti GP 4000 S2 25 mm (actually 25.3 mm) I'm running on my Shamal Ultra 15C wheels. Not sure if this will translate into a similar feel when riding.

I've ridden 23 mm clinchers for over the last 15 years in all conditions and only tried the 25 mms on my Shamals as an experiment and to be honest I can't say if they were quicker or not as I put them on the wheels from new and the wheels were an upgrade so felt quicker anyway. The 25 mm's were more comfortable than 23 mm's I'd ridden in the past but not revolutionary.

I'm coming to the opinion that the 23 mm's would be better on the Boras as should be as comfortable as the 25 mm's on my Shamals and if so I can see no reason to go larger. The only reason I'd use larger tyres is if it were faster as I have no issues with comfort and never have. Also surely the 23 mm will be more aero but I guess that depends on how the rim profile handles the airflow and I can't see any data on Bora's. Are the new ones still considered a V profile or are they a U??

Probably going to get a set of Contis in 23 mm. Out of interest, what tubes do you guys run as some companies warn against lightweight tubes. I love the black extenders that came with the wheels and think a 42 mm conti race light tube would be best??
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

cmcdonnell
Posts: 278
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

Just an update.

I tried a set of slightly worn 25mm Conti GP4000 SII's (90 PSI) and they came in at 26.7 on the 17C Bora's and looked noticeably wider than the rim, huge to my eyes, but more importantly would not clear my brakes (Super Record 2015 calipers) so that ruled them out. Put on a new set 23mm Conti GP4000 SII's (95 PSI) and they measured 24.8 and looked right as barely any wider than the rim and cleared by brakes by 3-4 mm. Very happy with the ride of the 23mm's and I'd say they feel as comfortable, in fact more comfortable, as the 25mm i'd been running on my 15C Shamals as they come up a similar width (the 25mm Conti GP4000 SII's at 90 PSI come in at 25.2 on the Shamal rims).

So overall for me the 25mm's were too wide and even if I could fit them the 23mm's are plenty comfortable enough as more aero so pretty much perfect on the Boras.
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

mimason
Posts: 654
Joined: Tue Feb 24, 2009 11:43 pm
Location: Florida

by mimason

Helpful information here, thanks all.

Bourquek
Posts: 44
Joined: Thu Nov 26, 2015 2:45 pm

by Bourquek

fogman wrote:I purchased some various clinchers from different manufacturers to see how they measure on my Bora One 35 clincher rims with the 24.2mm wide brake track. Pumped to 100psi. Here are the results:

Conti GP4000S II (23c) = 25.4mm
Conti GP4000S II (25c) = 26.7mm
Vredestein Senso (25c) = 25.4mm
Schwalbe One (25c) = 26.2mm



Awesome info! Especially comparing the Conti vs the Ones.

kova3023
Posts: 7
Joined: Sun Aug 30, 2015 2:30 pm

by kova3023

If you want the stability 25C
If you want a rate 23C

The letter also two unions.
Front-wheel drive (23C) + rear wheel (25C)

rst72
Posts: 33
Joined: Mon Oct 05, 2015 3:19 pm

by rst72

FWIW...I recently experimented with the new Vittoria Open Corsa G+ on HED Belgium rims (23mm wide).

23c measure 25mm
25c measure 27mm

cmcdonnell
Posts: 278
Joined: Sun Aug 02, 2015 7:50 pm

by cmcdonnell

I'd think the 23 mms would be more stable too as them match the rims external width more closely so by running 23mm (gp4000s) you are basically running 25mm in terms of comfort. Best of both worlds
Bianchi Oltre XR2 + Campagnolo Super Record 11 + Campagnolo Bora 50C
Litespeed T1 + Campagnolo Chorus 11 + Campagnolo Shamal Ultra

by Weenie


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wonkeu
Posts: 7
Joined: Wed Apr 20, 2016 2:28 am

by wonkeu

i prefer 25mm to 23mm. if you are not a professional rider, it might be safer than 23mm. just in my experience.

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