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I was on the phone with a rim builder yesterday and explained i was thinking about getting 35 tires up front and 40 in the rear for a slight bit more comfort for my seat. He was stumped as to why i wanted different sizes. I explain that i wanted an easier rolling/faster tire for road riding but didnt want to sacrafice comfort too much. He said that the narrower the tire the lighter, which is obvious, but he said that the wider tires have less rolling resistance. The wider tire is slightly hard to get up to speed, because of the weight, but once there its faster. That just doesnt make sence because i would think that a wider tire would have more of a contact area to the road than a skinnier tire, correct?

Sorry for the dumb question but i had to ask him twice because i just dont understand his thinking or maybe mine.. :D
 

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not a dumb question.
he's right. this article might interest you.
a relevant quote if you don't want to read it:
"the key to reducing rolling resistance is minimizing the energy lost to casing deformation, not minimizing how much tread is in contact with the ground. All other factors being equal, wider casings exhibit less 'bulge' as a percentage of their cross-section and also have a shorter section of deflected sidewall."
 

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mustangous said:
Wow. Thanks good article.

So than I should be better off with the 50 mm schwalbe over the 40
maybe, depends on your use for the bike. 23c tires are more aerodynamic and at road racing speeds most of the resistance comes from air drag not rolling resistance, hence narrow tires for fast road riders or riders who think they're fast.
 

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mustangous said:
Well I plan on using it for exercise and cruising on the streets. I will be in the NY'5 boro ride which is 42 miles.

So when is the wider tire more beneficial?
pretty much any time you're not worried about being a super fast road rocket while tucked down low in your drop bars.
 

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mustangous said:
I was on the phone with a rim builder yesterday and explained i was thinking about getting 35 tires up front and 40 in the rear for a slight bit more comfort for my seat. He was stumped as to why i wanted different sizes. I explain that i wanted an easier rolling/faster tire for road riding but didnt want to sacrafice comfort too much. He said that the narrower the tire the lighter, which is obvious, but he said that the wider tires have less rolling resistance. The wider tire is slightly hard to get up to speed, because of the weight, but once there its faster. That just doesnt make sence because i would think that a wider tire would have more of a contact area to the road than a skinnier tire, correct?

Sorry for the dumb question but i had to ask him twice because i just dont understand his thinking or maybe mine.. :D
Inflation pressure determines how large the contact patch is, not the tire size. A 35mm and 40mm tire each @ 50psi, supporting 100 pounds, will each have a contact area of 2sq/in. The shape will be different, but the area is the same.

Also, the 40mm tire will only provide more comfort if you reduce the air pressure. If comfort is the goal, you need the higher volume tire to be able to drop the pressure without increasing the chance of pinch flats.
 

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shiggy said:
Inflation pressure determines how large the contact patch is, not the tire size. A 35mm and 40mm tire each @ 50psi, supporting 100 pounds, will each have a contact area of 2sq/in. The shape will be different, but the area is the same.

Also, the 40mm tire will only provide more comfort if you reduce the air pressure. If comfort is the goal, you need the higher volume tire to be able to drop the pressure without increasing the chance of pinch flats.
Same area yes, but it'll be wider so your putting more tread down and picking it up, less length wise ofcourse, so you will get more drag.

There will be a optimal size for your weight and the ground your rolling over, really smooth tarmac and light person a 23mm would be best, up the weight or the roughness of the ground and a fatter tire will stall out less and then role better.

Going from 38mm to 50mm made my old hybrid much slower I can assure you of that, but at the same time increased the comfort to a rideable level.

Below 38mm for my 230lb's and the rough roads around here, likely wouldn't be much faster for me though.
 

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shiggy said:
Ummm...no. Go read the article linked in the first reply.
Running on a drum is not going to have the same effect as a flat road, it's going to force a wider / shorter contact patch due to the curve of the drum based on this I reject the claims found in that, sorry!!

Personal experience does suggest there is a sweet spot for the conditions and the persons weight, although it's not 23mm's for me for sure, it's not 50mm's either, somewhere inbetween.

My 3" tyre is not a faster roller and neither are fat bikes, unless the conditions match them so Sand or Snow then they are.
 

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mustangous said:
So any votes for recommendations?

Guess the 60c big apples are out...:D

40c or 50c? Im thinking ill try the 622 x 50c marathon supremes...
The problem even at 50c without a wide ish rim you've got to run it to hard or it's all squirmy and rides real bad on roads, although the rims survived better with 50c Marathons the comfort wasn't really up and the drag was noticeably worse because I couldn't run them soft enough.

Compared to the cheap Kenda 38mm's that came on it.

I dumped the bike, cheap wheels and V brakes don't agree with me, constantly truing the suckers.
 
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