Probably doesn't matter a few seconds either way.

I ran GP4000s in 23 on Flo 60/90 combo. Worked fine. If I did it again I'd do it on 25s...just for the tiny bit more comfort on the crappier conditioned sections of road.

I have Enve 7.9's and I also am racing IMWI and because of all the rain going on I have fear of nasty roads (dirty etc) from all of the storms and such that I am going to run a conservative combo instead of the fastest combo. I am running the 25mm GP4000's with butyl tubes @ 100psi - my theory is take a "few minute" penalty for something that is a little more puncture resistant (i know this is debatable). I know its a Enve wheel-set but for what its worth the 25mm GP4000's aerodynamically speaking is what they recommend in clincher setup (or the Schwalbe Pro One).

Enve also recommends far less PSI.

With all the recent rain, I'd use gatorskins.

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Pink? Maybe. Maybe not. You decide.

I reviewed the table on Enve's website and it was for Tubeless - not sure what is recommended for wheels running tubes in them but my GP4000's @ 100psi measures out to be a little larger than 28mm width and the rim itself is 29mm so I don't think its aerodynamically hindering (I read that you want the tire to be just slightly smaller than the rim).

I have just always ran that much pressure - never tried lowering it before haha.

Well whatever it is, it is far less than 100 psi for 25mm wheel. By running 100 psi you are losing the benefit of a 25mm tire.

Do you think that latex tubes are more prone to punctures?

If that was directed at me than no I don't think they are more prone - I just have not had very good luck with them and Enve does not recommend them.

I already run high tire pressure as was pointed out so I am not worried about a snake bite etc. I made a thread on here not too long ago about the issues I was having and regardless of what happened or how it happened etc I am simply not running them for this distance.

TrainerRoad Podcast had an episode with the guys from Flo and they were talking about tires and their wheels and what tested fastest. I think they said that the 25mm Conti Sii was the fastest on their rims. You should find and listen to that episode! It may have some insights for you. It has been a while since I listened to it so I could be wrong on my recollection.

Are you that close to winning your age group?

If so, then look for all advantages.

If not, then I would not stress about it.

Any ideas on why you have had bad luck with latex tubes?

Why does Enve not recommend latex tubes?

That's a good question - I had a lot of little issues with Latex tubes that lead me to this point.

I will start off by saying that the data/research out there is unquestionable and my personal feel with latex also indicates that they are superior and "easy" or "free" upgrades to achieving less rolling resistance/speed.

Here was my issues or struggle with them;

1. Ruined 2 tubes upon initial instillation - When I decided to try and convert tubes for the race season during January of 2017 I was not aware of how fragile the tubes were. I ordered 2 tubes and while installing them I ripped one with a tire lever (The Enves are very hard to install tires on) and the other one I cannot remember what happened but I did something silly. I took to the forums and online and learned about how fragile they were and how to better install them (powder them, air them up, push them up into the tire, verify not inbetween bead etc).

2. Latex tube found its way into a spoke nipple hole - I Finally got 2 tubes installed with no issues, I repeated the process a few times to verify I was doing it correct. I at this point had purchased 4 latex tubes - I went and did my first race and they performed great! I was sitting after the race at a campground relaxing and heard my front tire pop....... When I got home and inspected the latex tube had worked its way under the plastic rim strip (was slightly pinched there) and into the spoke nipple hole eventually popping.

3. Latex tube gets under tire bead - This is the one that finally did it for me, I am now 5 Latex tubes into this project or test and I approach a 70.3. I fixed the tire/tube combos a few months prior after the spoke nipple popping it and let the wheels hang/sit in my garage. I did not test the tubes/tires before getting to the race and the day before during my bike practice I aired them up like normal and went on to race. When I get to T1 my tire bead is blown off and the tube is torn in a very long length. I ended up with 2 flats that day and beyond frustrated. I believe the issue was that while sitting in my garage the bead unhooked off the rim and when I just willingly pumped it up the tube got caught between the bead and rim...... The other factor could be that the Enve rims have some Burrs on the beads that are fairly aggressive, maybe that was the issue.

I am now here a month and some days after my 70.3 and have just elected to go back to Butyl for the time being, why does Enve not recommend the tubes? I believe it is something to do with the brake heat - maybe its the rim imperfections will cut them more easily but I am not certain outside I know they just don't recommend it.

With that being said I had seen my latex tubes survive a puncture and not pop and as stated before they felt amazing. If you care to read here are the threads I had on it;

https://forum.slowtwitch.com/...w_P6649476/#p6649476

https://forum.slowtwitch.com/...n_P6691732/#p6691732

Combined Aero/.crr rankings on Flo 60:

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"They're made of latex, not nitroglycerin"

I run the Enve 7.8 combo with latex tubes and Conti 4000 full time around Madison. Psi is 85-90 front and 90-95 rear. I'm 175 lbs. Got probably 4500 miles on that combo and it works really well.

*One exception: Rim tape. If you use the stock Enve rim tape then get it out and run two layers of the tubeless tape that comes with the wheel or get something else. The rim strips will eventually rub the inner tube and cause mystery punctures. Only took about 7 flats to figure that out.

Thanks for the feedback!

I am right at 170lbs so its good to hear someone else is running higher pressure - I have not given up on the Latex just not using them right now. I agree that the Enve rim tape is not the best and I removed mine and double rapped stans tape on the rim and left it alone.

Another couple of tips:

Sounds like you already did the double wrap rim tape. Good fix.

Latex: Inflate the tube to just larger than the tire before installation. Get one side of a tire on the rim and "settle" that part of the tire into the channel on the wheel, not at an edge. It gives more room for the tire to go on initially all the way around. Add a bit of baby powder and run around inside the tire. Insert the latex valve into the rim and tuck the slightly inflated tube inside full length of the tire (you may need to deflate the tube a bit). Tube and one side of the tire will now be on the rim, but the tube won't be "in" the rim. Use the tire now to fully tuck the tube inside the rim sidewall; the tube should still be slightly inflated. Now tuck the other edge of the tire on the rim, into the center channel. You'll get about 2/3 to 3/4 of the tire on easily, with the tube tucked up and out of your way. You might need to deflate the tube a bit more now and use a tire iron to pop the remaining portion of the tire on the rim. Tire might sit down in the channels and not up on the bead rim, that is OK. Squeezing the tire along the entire length (a bit at a time) should allow you to see if any portion of the tube is stuck outside the tire. It shouldn't be.

Now, the hard part. Inflate the tube. The inflation itself isn't hard, it is scary, however, when enough internal pressure pops the tire out of the lower inside channel and up onto the wheel rim bead. It should pop 1-3 times to snug into place. That is a bit loud and harrowing sound but you'll get used to it. Inflate to desired pressure.

Good luck

Great tip for those looking at this thread!

This is how I "learned" how to do it and is explained well - thank you!

With all the recent rain, I'd use these....