Slime tubes with GP5000's? Rolling resistance?

I’m well aware of the watt savings I’m going to see from switching my gatorskins to GP5000’s. I was listening to a TR episode and they were talking about a guy losing IM because of running gatorskins, and one of the guys under his breath jokingly stated that he was probably running slime tubes as well. I’m just wondering if anyone has any data about wattage losses from slime tubes. Seems from butyl to latex is about 2-4 watts overall savings, but I couldn’t find anything on switching from slime tubes to something like continental’s regular race 28 butyl tubes. I have a bunch of extra slime tubes I’m wondering if I should not use with the GP5000’s.

If someone tells me I was losing an additional 10 watts on those this year, I don’t know if I’m going to be happy going into the next season gaining 30-40 watts, or sad knowing that I was just losing them all season…

Hi David,

Check here the data you are looking for and have fun:

Tires Test:

Tubes Test:

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awesome! Thanks man! I was on the page but just didn’t click on the link that talked about sealant separately.

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Yo @davidnharris why not just run the slime tubes training and switch them out with latex or something better for the event/race? Pushing watts on a PM has zero to do with saving watts via aero or Crr etc…

You are not limited to those two options (slime tubes or latex tubes): you can also add sealant to standard latex tubes, as long as the valve core is removable.

The result would be a more puncture proof tube with nice, low rolling resistance.

That’s probably what I’ll do, not sure I’m ready for latex though. The difference between a 70g light and 100g racer tube is about .7 watts/30g, so I made the assumption that using the 170g slime tubes over the 100g racers I’ll have about 3.26w lost from weight and 1w lost from slime, so 4.26w total potentially. Maybe my assumptions are incorrect, but I’ll be switching to the 100g racers for everything, most because I want to feel all the difference at once after 2 years of losing between 20-40w. Maybe I’ll try some latex for a race.

I think you are underestimating the wattage gains from using a latex tube…especially if you are coming from Slime tubes.

Regardless, another benefit of latex is the increased comfort and better puncture resistance.

There really is no good reason to choose butyl over latex, especially on race day.


Yeah, that was math on just butyl. I want to do some more math later on latex when I get a chance.

@davidnharrisI don’t understand the 20-40w reference…

At 100psi from the link above, 20.5w for the gatorskins minus 10.7w for the gp5000s = 9.7w lost per tire = 18.4 total watts lost if using a set of gatorskins over gp5000s. Then add in the 4ish watts total from my other math and it’s about 22w lost. I just estimated up to 40 because I’ve “heard” people say up to 20w per tire lost with gatorskins on, although the link doesn’t support what I’ve "heard.

Maybe it was 40w total lost with the 2 tires, but you have to actually run a set of wheels, so compared to others you lose about 18w total when comparing the best to the worst tires.

I dont race FWIW. I did try latex tubes all last season and found them to feel great and possibly faster. I will stay with them again this season I think - just wondering if others have any tips for what is a semi regular occurrence:
On two different bikes my rear tube has gone completely flat on more than one occasion after a ride. During the ride it felt fine - once I left my bike on the stand in the house - the rear would deflate completely by the next morning. Sometimes reinflating helped and other times it didn’t.
I know they lose air quicker and inflate prior to every ride.
I removed and reinstalled the valve core in case it was well seated. One bike has valve extenders and the other doesn’t - so I checked that as well. It was a head scratcher and wanted to throw this out there in case anyone has any insight… OP - I personally felt the latex felt so much better and I weight 182 and ride on some rough roads - I guess they have more give to them. I did get one pinch flat this summer but in all fairness I went OTB and did a complete summersault and my bike flew over me into a ditch - so I cant fault the tube.

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Thanks for the insight. Ater all this chat I’m actually thinking maybe I should just convert my mavic ksyrium elites to tubeless, if that’s even possible.

This is where we part ways…:slight_smile:

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Gotcha. IME…Going from gatorskins with slime tubes to GP5k with butyl or latex you will notice a difference in speed for the same power with no special equipment other than your head unit. Total WAG from my numbers but, 40W at my threshold on my TT bike is around 1.5mph. (320W=27.5mph and 280w=26+ a little mph). So I say go out and run the slow tire with slow tube then run the fast tire and fast tube and find out.

I could not notice a difference in speed on my head unit at about 10w or less. Just noise.
While I didn’t Chung method it I spend enough time on smooth flat unobstructed roads in no wind similar temps to know. I think between running a GP5K with butyl and latex would be in this same ballpark. Not saying there isn’t a difference just that you won’t notice it on the head unit. Some of these little gains are only measured over long distances in seconds or fraction of seconds/km.

Latex feels maybe a little different (cornering) and they are actually more durable but, just a little more care to install and take care of. Lightweight butyl I’ve never felt necessary or comfortable with the possibility of a blowout. So I generally run butyl for training and racing. If on the TT bike for a race I’ll usually install latex a few day before and just run them til they die and put butyl back in until the next race.

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DO NOT do this,you can convert any MTB wheel to tubeless because of the low pressures involved. You should never try and convert a non-tubeless road shell to tubeless.

Just use latex tubes and the 5000’s and you’ll be light years ahead of where you were with the GatorSkins.

Thanks for looking out for me man! I’d have watched some YouTube videos at least before deciding not to try and off myself.

the may be slower because the selant hase to be moved throught the tube