revtothelimit - motorbike forum

Been using swmbo road bike lately as awaiting new bearings for the trek.
She has a very basic halfords carrera, but on the road, by christ does it go some compared to my old mtb.
Guess that is the difference between knobblies and road tyres.

Yep, skinny tyres, inflated to "rock hard" psi (ish) and much better riding position for the road allows better power transfer. That's why the gearing is so different.

overall though in the grand scheme of things they're not THAT different though.

If you can MTB at sat 11mph on the road, you won't get 20mph average on a road bike... more like 13mph average. In the same way, if you can average 20mph on a Roadie, you'll still get 17.5-18mph av on a MTB....

weeksy wrote: Wed Sep 02, 2020 8:28 am overall though in the grand scheme of things they're not THAT different though.

If you can MTB at sat 11mph on the road, you won't get 20mph average on a road bike... more like 13mph average. In the same way, if you can average 20mph on a Roadie, you'll still get 17.5-18mph av on a MTB....

But you will be working much harder! Switching from knobblies to dual purpose tyres helps a bit.

I'm not sure the difference is all that.

I went from MTB 35psi 2.6 chonky tyres to some 55pi 2.2 Race kings and the difference was insane. The 2.2 Race Kings (which are about as fast rolling as you can realistically get for a XC tyre before you start looking at thiiiiiin stuff) compared to 28c all weather road bike tyres is way too similar. I can just about average the same kp/h over an hour mixed loop on a road and MTB bike. YMMV.

weeksy wrote: Wed Sep 02, 2020 8:28 am overall though in the grand scheme of things they're not THAT different though.

If you can MTB at sat 11mph on the road, you won't get 20mph average on a road bike... more like 13mph average. In the same way, if you can average 20mph on a Roadie, you'll still get 17.5-18mph av on a MTB....

You may no longer have KTMs but some things don't change. They really are that different. The whole position of the bike is made for more efficient pedaling. That's also why XC MTBs are so very different to what you (and I) ride when we go out on the trail. That efficiency is why a road bike will have significantly lower gearing, particularly as they don't need higher gearing to climb.

lostboy wrote: Wed Sep 02, 2020 10:01 am <snip>

That efficiency is why a road bike will have significantly lower gearing, particularly as they don't need higher gearing to climb.

I know what you mean, but it's the other way round. Road bikes have higher gearing.

lostboy wrote: Wed Sep 02, 2020 10:01 am

weeksy wrote: Wed Sep 02, 2020 8:28 am overall though in the grand scheme of things they're not THAT different though.

If you can MTB at sat 11mph on the road, you won't get 20mph average on a road bike... more like 13mph average. In the same way, if you can average 20mph on a Roadie, you'll still get 17.5-18mph av on a MTB....

You may no longer have KTMs but some things don't change. They really are that different. The whole position of the bike is made for more efficient pedaling. That's also why XC MTBs are so very different to what you (and I) ride when we go out on the trail. That efficiency is why a road bike will have significantly lower gearing, particularly as they don't need higher gearing to climb.

My post was relating to speed, not the actual bikes.

Try a HT for 10 miles and a Roadie for 10 miles, same effort/HR and compare speeds.

weeksy wrote: Wed Sep 02, 2020 12:49 pm

lostboy wrote: Wed Sep 02, 2020 10:01 am

weeksy wrote: Wed Sep 02, 2020 8:28 am overall though in the grand scheme of things they're not THAT different though.

If you can MTB at sat 11mph on the road, you won't get 20mph average on a road bike... more like 13mph average. In the same way, if you can average 20mph on a Roadie, you'll still get 17.5-18mph av on a MTB....

You may no longer have KTMs but some things don't change. They really are that different. The whole position of the bike is made for more efficient pedaling. That's also why XC MTBs are so very different to what you (and I) ride when we go out on the trail. That efficiency is why a road bike will have significantly lower gearing, particularly as they don't need higher gearing to climb.

My post was relating to speed, not the actual bikes.

Try a HT for 10 miles and a Roadie for 10 miles, same effort/HR and compare speeds.

I do it quite often as my commute to work can be down with either 50% offroad or completely on road. The first/last few miles are always identical. I know EXACTLY how much more efficient the road bike is and it's not close! (Cube Agree C62 disc with 30mm Schwalbe One tubeless vs Cotic Solaris with WTB 2.3 Vigilante front and 2.2 Trail Boss rear)