Rotational mass of tyres

[CoolC]

Here's one for those with more knowledge than me.

I ride an MTB, but on Thursday we (6 of us) will be doing the St Bees to Robin Hoods Bay C2C.

As it will be a tarmac crossing I decided to get a set of slick road tyres to make things easier.

Well yesterday I went out for a ride with the slicks on, but it actually felt a little harder than usual. I think this might be down to the weight of the slicks against the off road tyres I have.

My "normal" off road tyres are Bontrager XR1 http://bontrager.com/model/09483

My slicks are Bontrager H2 http://bontrager.com/model/07795

I haven't weighed them but the H2 definitely feel heavier, and the XR1's are a small blocked hardpack tyre. Would there really be a difference to the detriment on the slicks or is my mind playing tricks on me?

[BadgerBenji]

What pressures are you running in them?

[Mr E]

Increased rotational mass would affect acceleration and direction change.

Shouldn't hurt in a straight line. Reduce rolling resistance should make life easier...

[CoolC]

Running the knobblys at 50psi on the road, and the slicks at 70psi

It's probably just my imagination playing tricks on me. Either that or I'm creating my excuses early for PPP

[Mr Will]

70 seems pretty low compared to a road bike tyre, pump them up to the max on the sidewall and see if there is any difference, then work down from there :-)

[CoolC]

80 is the max on the sidewall of the slicks.

[scottri]

I put slicks on my hardtail MTB when I did C2C, I wasn't sure there was much of a difference either..... until I put knobblys back on!

[CoolC]

We've decided to put the off road tyres on for the first couple of days where there are some off road options, and then change over to slicks on day 3 where we will be where the cars are parked, as day's 3 and 4 are all road.