I have used Schwalbe Kojaks on my 26″ “road” bikes for quite a while now and they are great all-round tyres but their rather basic stiff casing limits their performance both in terms of speed and comfort. It’s the same story with almost all high volume 26″ slicks. So I’ve decided to get some top end MTB tyres and shave them!
Racing Ralphs 2.10 seemed to be the best candidates with their very low rolling resistance but better durability and puncture protection than Furious Freds and Rocket Rons.
Most of people automatically assume that mountain bike tyres are “slow and heavy” but it’s as wrong as assuming that all road tyres are lightweight and fast. It’s the design of the casing not the label that makes a tyre (potentially) fast or slow.
In case of Racing Ralphs once you remove the tread you end up with a thin and flexible 120TPI slick tyre with no puncture protection (lower rolling resistance) that weighs just 400g for a 2.10″ (54mm) version. No other slick on the market offers that.
My Shaven Ralphs are run tubeless on Stans Flow rims (54mm actual width) at around 20PSI front and 30PSI rear (using the 15% tyre drop method as a starting point http://www.biketinker.com/tire-pressure-calculator, http://www.bikequarterly.com/images/TireDrop.pdf) It may seem low but any more than that only reduces comfort and doesn’t make the bike any faster.
So how fast can you go on these?
On 1.00-2.30h long routes I consistently clock 18.5-20.0mph on some broken country roads. That’s riding mostly on drops, mostly flat, often with a commuting backpack, baggies and just 1.5″ handlebar drop. I realise that average speeds usually don’t mean a lot but I believe that in this case can demonstrate the potential of the tyres and change some misconceptions about rolling resistance.