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Re: Tubes crr comparo - latex crushes the competition

Posted: Mon Aug 19, 2019 7:40 pm
by TobinHatesYou
dooglehead2 wrote:
Mon Aug 19, 2019 7:23 pm
aeroisnteverything wrote:
Mon Aug 19, 2019 5:13 pm
That's an odd hot tip - because it seems only relevant for the hill climbing portion of the ride (and even then might be a wash), and not for any other part of the ride.
I agree in most cases, but I'm interested in building the fastest hill climbing bike because I mostly do hillclimb races where nearly the entire ride is the hill climbing portion.

For a pure hill climbing bike, I imagine you’d be best off with the Corsa Speed G2.0TLR and the weight penalty of clincher rims. You could even remove excess sealant with a syringe after the initial seat/seal.

Re: Tubes crr comparo - latex crushes the competition

Posted: Mon Aug 19, 2019 7:52 pm
by aeroisnteverything
TobinHatesYou wrote:
Mon Aug 19, 2019 7:40 pm

For a pure hill climbing bike, I imagine you’d be best off with the Corsa Speed G2.0TLR and the weight penalty of clincher rims. You could even remove excess sealant with a syringe after the initial seat/seal.
Yep, math says this is correct at a 10% gradient. So long as clincher weight penalty is less than, say, 300g - which is a lot.

Re: Tubes crr comparo - latex crushes the competition

Posted: Mon Aug 19, 2019 7:52 pm
by Weenie

Re: Tubes crr comparo - latex crushes the competition

Posted: Mon Aug 19, 2019 9:41 pm
by RocketRacing
Robert chung did the math, and forgive if i error here, but a 0.001 reduction in crr is worth the same as removing 500g... but only when you are climbing a 10% Gradient. Any gradient less than 10% and the improved crr greatly outperforms the reduced weight.

So you need REALLY light tubolitos before they outperform a latex tube. (Or maybe use the tubo-s or whatever it is called).

Re: Tubes crr comparo - latex crushes the competition

Posted: Mon Aug 19, 2019 9:49 pm
by hambini
Am I the only one who regularly pumps the tyres up to the rated sidewall pressure? ie my Conti's get the full 8.5 bar, I can't imagine riding with 6 bar, it will feel like riding through treacle.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 3:00 am
by pdlpsher1
I checked the latex tubes I have in the closet. It’s Vittoria 17-24mm with a weight of 65g. Do they even sell this tube anymore? I wouldn’t use any latex tubes less than 85g so I guess I won’t even bother trying these on.


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Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 4:32 am
by JerryLook
The Vittoria latex tubes I have weigh around 75 grams each, and are the smaller size (19-24). They have weighed that for the last couple of years I have used them. At the moment I’m using those tubes in tires that measure 27mm.

The ones you have are a nice weight.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 6:56 am
by mrlobber
That latex trumps everything for RR (except the latest tubeless stuff) has not exactly been a secret for years.
I run latex on pretty much all my wheels (clinchers, tubs), and usually get around one flat per 5-6k km, including commutes.
I also don't have any problems installing latex tubes, which sometimes is mentioned as a potential problem why avoid them.

The only place where I generally avoid riding latex clinchers, are sustained climbs and the descents which follow (and so far also only because of rim brakes) - this is the world of tubulars for me.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 8:47 am
by eins4eins
i wonder about the comments about the conti wet grip. in my opinion no tire is coming even close to their wet grip. The conti competition was a benchmark in the wet, but the GP5000 is even better. They stick superb in wet conditions and even when loosing grip, its still controllable, while other tires like vittoria or especially veloflex loose grip suddenly without giving a chance to react.

i won cat1-2 races in the rain this year, attributing a big part of the success to the GP5000, as i was making up a huge amount of time in corners due to the endless confidence those tires give.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 11:43 am
by RocketRacing
hambini wrote:
Mon Aug 19, 2019 9:49 pm
Am I the only one who regularly pumps the tyres up to the rated sidewall pressure? ie my Conti's get the full 8.5 bar, I can't imagine riding with 6 bar, it will feel like riding through treacle.
Outside a heavy rider and some very very nice roads, nope.

Why are you running so high? I presume you run 23c, and are in the 140lbs range.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 12:49 pm
by XCProMD
hambini wrote:Am I the only one who regularly pumps the tyres up to the rated sidewall pressure? ie my Conti's get the full 8.5 bar, I can't imagine riding with 6 bar, it will feel like riding through treacle.
Bit less than rated pressure but tend to agree. Thin casings need tension.


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Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 1:56 pm
by hambini
RocketRacing wrote:
Tue Aug 20, 2019 11:43 am
hambini wrote:
Mon Aug 19, 2019 9:49 pm
Am I the only one who regularly pumps the tyres up to the rated sidewall pressure? ie my Conti's get the full 8.5 bar, I can't imagine riding with 6 bar, it will feel like riding through treacle.
Outside a heavy rider and some very very nice roads, nope.

Why are you running so high? I presume you run 23c, and are in the 140lbs range.
I'm 72kg so 160lbs

On my TT bike which has a 23 front and 25 rear, I go for the max sidewall pressure. Any less than that and it's power loss I can do without. Are roads in the US really that bad for riding on?

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 2:15 pm
by CrankyCarbon
hambini wrote:
Tue Aug 20, 2019 1:56 pm
....... Are roads in the US really that bad for riding on?
Many of the roads in the US are from questionable to poor. Some states are much better. They tend to "patch" first for a long time before making any replacements.

For instance, in Michigan it's not very good. Many riders who ride closer to the edge of the road will get flats all the time due to the built up debris. I tend to ride away from that and don't generally have problems. Of course there are new roads too but it seems as though money to fix the roads is little. There are roads that are totally disasterous too.

Some roads even become impassable for cars & bikes. Earlier this spring I avoided about 3 miles of one concrete road as I could see many large potholes, past the rebar to the lower road support gravel.

Tweet map of bad US roads
https://www.metrotimes.com/the-scene/ar ... o-this-map

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 2:48 pm
by AJS914
I'm in New Mexico. The roads are actually in good condition but they are coarse. If I road at 8.5bar I'd feel a constant buzz in my bars and body. I ride 25mm Conti GP4000s at 80/85psi (5.5/5.8bar). I used to live in Washington state where the roads were smoother and there I rode 90/95psi.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 5:30 pm
by mikemelbrooks
hambini wrote:
Mon Aug 19, 2019 9:49 pm
Am I the only one who regularly pumps the tyres up to the rated sidewall pressure? ie my Conti's get the full 8.5 bar, I can't imagine riding with 6 bar, it will feel like riding through treacle.
The current thinking seems to be unless you are riding on a smooth indoor track the optimum tyre pressure will be much lower than that, if you get the chance listen to Josh Poertners marginal gains pod casts, ( the gist of it being that we feel we are going faster when we are being shook around by over inflated tyres). For the record I am 76kgs and usually ride at 85-90psi on a 23mm tyre. And I live not far from you.

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 5:36 pm
by mikemelbrooks
hambini wrote:
Mon Aug 19, 2019 9:49 pm



On my TT bike which has a 23 front and 25 rear, I go for the max sidewall pressure. Any less than that and it's power loss I can do without.
If you can’t measure the power loss how can you tell?

Re: Tubes crr comparo - latex crushes the competition

Posted: Tue Aug 20, 2019 5:36 pm
by Weenie