I’m going to have to replace the rear tyre on my road (cyclocross) bike within a matter of months.  I want to stick with Schwalbe Marathon Plus, which suffer so few punctures that I have lost the skill of fixing punctures.

I have the option of a 28 mm (from a shop 40 km distant) or 35 mm (shop 10 km distant).

I don’t remember any dramatic change when I previously switched from 35 -> 28 mm.  The 35s are nominally 85 psi, the 28s 110 psi.  
I ride 97% tarmac albeit some rough roads, and occasionally gravel, sandy roads and rarely mud dirt tracks.  My buddy rides 25 mm on the same route, but he has better bike handling skills.

How much difference do you reckon between 35s at 85 psi and 28s at 110 psi

- on ordinary tarmac (efficiency and speed)?

- on gravel and sand (getting bogged down)?

On 7/12/2024 at 11:01 PM, StreetCowboy said:

I’m going to have to replace the rear tyre on my road (cyclocross) bike within a matter of months.  I want to stick with Schwalbe Marathon Plus, which suffer so few punctures that I have lost the skill of fixing punctures.

I have the option of a 28 mm (from a shop 40 km distant) or 35 mm (shop 10 km distant).

I don’t remember any dramatic change when I previously switched from 35 -> 28 mm.  The 35s are nominally 85 psi, the 28s 110 psi.  
I ride 97% tarmac albeit some rough roads, and occasionally gravel, sandy roads and rarely mud dirt tracks.  My buddy rides 25 mm on the same route, but he has better bike handling skills.

How much difference do you reckon between 35s at 85 psi and 28s at 110 psi

- on ordinary tarmac (efficiency and speed)?

- on gravel and sand (getting bogged down)?

You’ll get a much smoother ride with the 35mm and you might find the rolling resistance is lower.

 

Certainly if going over sand I would choose a wider tire .

 

 

On 8/28/2024 at 11:33 AM, Chomper Higgot said:

You’ll get a much smoother ride with the 35mm and you might find the rolling resistance is lower.

 

Certainly if going over sand I would choose a wider tire .

Given that the sand is 50 km away, I am not sure it should be the main consideration...
I really can't say I've noticed any major difference, in all my tyre changes to date, and Schwalbe Marathons are such bar-stewards to fit, I 'm not sure I want to do a controlled taste-test challenge. 

I wound nevertheless look at lower tire pressures, I ride 25mm Continental GP 5000 and during the rainy season 25mm Continental 4 seasons.

 

I inflate to 85psi front and 90psi rear which gives a smooth ride with the lowest rolling resistance for my weight.

 

 

I've ordered 2 x 35 mm.
One will go on the front of the shopping bike.  
I'll check all my other tyres to see if I have a smaller tyre I can rotate on to the back of the road bike - it has a 35 mm on the front, I think - and if not, I'll put the 35 mm on the back, and over-inflate it to 90 psi (nominal max. 85 psi).