Latex vs Butyl

I’m sure most folk (if not everyone) are familiar with the claims that Latex tubes run faster than Butyl but is this really true and measurable?  Well, I recently conducted an interesting experiment.

After building the Stelbel last Summer I threw on an old pair of Vittoria Corsa tyres and was going to put in Latex tubes but found that the new Campagnolo Bora rims were a really (too) tight fit for the valve stems on Vittoria Latex tubes.  Weird.  Anyway I threw in a set of Continental Butyl tubes instead.

More on the Stelbel ride later in another article but suffice to say, the ride is fantastic and there seemed to be little difference between the average speed between the Stelbel and #1 Pinarello out on the road.  Given that I’m in a new location I was setting PBs on segments on both bikes though the Pinarello had the edge but the Stelbel, despite being heavier was not far off par even on climbs and I was setting PBs on segments that I had ridden on both bikes.  I suspect the Bora wheels on the Stelbel may have the edge over the Shamals on the Pinarello that may counter the weight difference – but that might only be true at a decent speed when greater Aero would be apparent.

Anyway, things became interesting over the Winter and in Lockdown when I’ve retreated to the “Gym” riding mainly on Rollers.

I was somewhat surprised (concerned?) that the Stelbel was 2-3 mph down on the Pinarello at max cruise (Threshold? – I don’t use a power meter).  Initially I thought it was me and down to fitness levels, so I did a swap of bikes on the same session and the Stelbel was definitely slower or more effort for the same speed.  Both bikes run Campag Record Groupset so that did not seem a likely cause but what was noticeable was that the Stelbel definitely felt heavier and sounded “stickier” in respect of tyre noise on the rollers.   Again tyres are comparable with Vittoria Corsa on both though the Pinarello has Graphene vs the older version on the Stelbel and both running at 100 psi.  Also when I stopped pedalling on the Stelbel the Rollers span down to a stop quicker than with the Pinarello.  Weird.

So out of interest I swapped out the inner tubes for Latex.  Note that the valve is still a tight fit in the Bora rims and I need remove or replace the plastic guide that is making them too tight.  I have ones from a worn out set of Shamal rims that hopefully will fit.

Anyway, back on the Rollers.  Like night and day.  Rolling at the same max cruise as the Pinarello!

How much does this translate to road riding?  Well I have no scientific measure but have to assume that there is a difference.  It’s not the 2-3 mph I see on the rollers but it will be interesting when lockdown eases – and the weather improves – and I get back out on the road.  Actually we are allowed out for exercise here but it’s been pretty cold and miserably wet this winter and I must be getting soft with age.

Also despite having the Stelbel built in Stainless Steel to be bulletproof to weather, I still don’t want to get it muddy!

So Latex definitely seems to have it, at least on Rollers.  Though I have to wonder whether optimising my speed and minimising effort on Rollers is really the point of indoor training!