Tyres & Rim width dilemma

short circuit

Hi .. with too much time on my hands sitting indoors ... am trying to put a cross bike/commuter/credit card tourer together.

I might be putting up a thread on the adverts section of the forum looking for some parts ... ...

Frame has been ordered and should arrive with the summer.

But more to the point of this thread, I am currently using Mavic Open Pros with Ultegra hubs on my bike. The rim width is 15mm and the Mavic site says I should be able to run upto 28mm tyres on them. I know some people here use the cross bike for touring/commute as well as for cross .. so what rim width do you have ... and what tyre width do you use on road vs on cross. Can I run 35/38mm on the same rims for the duration of the iceage.

I had a look on the Mavin site and the wider rim at 19mm is the A719 ... but the minimum tyre width recommended for those is 28mm .. which means I will lose the flexibility to run smaller tyres ... is there a magic middle ground.

Also .. anyone have a magic width for Dublin commute ... I have so far only tried 25mm but am intrigued by the comments of silky ride with no road buzz on 32 and 35mm road slicks .. is there really that much difference.

Lumen

35mm is fine on Open Pros.

In my experience of wider road tyres (Vittoria Randonneur, 32mm I think) they don't offer a magic carpet ride. Maybe I was running pressures too high, around 80psi as I recall; I wanted to minimize rolling resistance.

TBH I don't find ride quality on 23mm tyres unacceptable at 90-100psi. If you go round the potholes, 23mm is fine, if you go into them then 32mm isn't enough.

I think that tyre construction is important, regardless of width.

short circuit

Using 35mm tyres with 15mm rim seems to go against Mr Brown's recommendation ... but I will go with you as it will save me some money right now and if going wide isn't going to give me a magic carpet ride, don't see myself using 32s and above that much .... apart from in this kind of weather.

blorg

35s on Open Pros are fine, I have used that size on them before and indeed am putting on 37s now. I disagree strongly with Lumen there, I think there is a phenomenal comfort difference between 23/25s (I was moving from 25s) and 35s, without much loss of speed if any. I also think there is a big difference between 23s and 25s (went to 25s on the road bike for the winter.)

IM0

the king has a great chart up for deciding which tyres work with which rims it errs on the site of caution though so can probably get away with an x either side of the chart 'bar'

PS scroll to the bottom page if you dont want your head melted, and stick to the point and squirt chart!

Lumen

blorg wrote: »

I think there is a phenomenal comfort difference between 23/25s (I was moving from 25s) and 35s

Which 35s and at what pressures?

Bunnyhopper

me@ucd wrote: »

the king has a great chart up for deciding which tyres work with which rims it errs on the site of caution though so can probably get away with an x either side of the chart 'bar'

Definitely erring on the side of caution. If I'm reading it correctly, it suggests you can't put a 57mm (2.25") tyre on a 19mm rim, which rules out a fairly common XC combination.

short circuit

Lumen wrote: »

Which 35s and at what pressures?

I got the below chart from here and this would suggest that at 80kg total weight with 45 - 55 front back split, you should be running about 45 front and 65 rear ... this seems awfully low to me ... though he goes into some level of explanation for optimising comfort vs rolling resistance.

Lumen

short circuit wrote: »

I got the below chart from here and this would suggest that at 80kg total weight with 45 - 55 front back split, you should be running about 45 front and 65 rear ... this seems awfully low to me ... though he goes into some level of explanation for optimising comfort vs rolling resistance.

Thanks. The way I read it I should be using about 55% of my preferred 23mm pressure (90/100 psi) with 32mm tyres, which is about 50/55 psi.

IM0

Bunnyhopper wrote: »

Definitely erring on the side of caution. If I'm reading it correctly, it suggests you can't put a 57mm (2.25") tyre on a 19mm rim, which rules out a fairly common XC combination.

the king has a great chart up for deciding which tyres work with which rims

blorg

Lumen wrote: »

Which 35s and at what pressures?

I went from Gatorskin 25s at 100/90 to Marathon Racer 35s at the maximum recommended pressure or thereabouts (95 PSI)

short circuit

blorg wrote: »

I went from Gatorskin 25s at 100/90 to Marathon Racer 35s at the maximum recommended pressure or thereabouts (95 PSI)

That seems way high from the recommended pressure for 35s ... have you tried it any lower to see if increases rolling resistance ... and makes you slower.

I am surprised you are seeing such a difference purely from size and not reducing your pressure at all ... I wonder its just just not the tyre compound .. nothing with size or pressure.

On flats .. you might actually be faster on bigger tyres as by running on similar pressure .. you are effectively reducing the tyre deformation for a bigger tyre and hence reducing rolling resistance