Erich_E

I figured I stick here since you guys tend to be a bit less aggressive in your responses as compared to the general population!

Anyway, I've been biking and running a bit for the last 4 months and I'm down from 245 to about 230 right now. I've gone from a true couch potato to jogging up to 6 miles at a 12 min/mile pace, and I've done 45 miles on the bike in a single stint. In the last two months I've put on about 400 miles on the bike, and about 40 miles running (jogging?). Trying to keep up with my 7 year old son that's a sports nut is a great incentive!
Right now I've been averaging around 15mph thru about 16 miles without really pushing it too hard. But I've been conned into being a part of a relay team in a few weeks.
I started out with a Jamis Aurora Elite and I'm planning on taking off the fenders and rear rack for the 16 miles, but I was wondering about how much of a gain I could expect if I went with some more road style 28mm tires vs the 35mm Clement UHS tires. Would it be worthwhile at all, other than making my touring bike look a little more respectable? Now that I've been out a bit more I'm thinking I should have gone with a more road style bike, so what do you guys think?
Thanks!

Duck0872

My road bike has 28's and my fitness bike has 35's, and the bikes are pretty close to the same weight. Over the course of a 15 mile ride I usually average about 1 mph faster on the road bike. The 28's definitely feel more maneuverable and accelerate a lot easier than the 35's. I always feel like I'm pushing harder to maintain the same pace with the 35's.

Spoonrobot 

Probably little to no gain. I'm having a hard time telling the difference between 26 mm and 42 mm tires in my 9 month experiment. The data does not appear to be statistically different with respect to average speed.

I guess you would probably just gain a greater propensity for pinch flatting.

bgraham111

You could get some really noticeable gains from switching tires. I assume your ride will be on a road or other paved surface. The width isn't as important as the overall tire. You should be able to find a "supple" tire, even at 35, that will make riding so much nicer and faster. So... look for "supple" tires, and don't worry too much about the width.

I'm currently riding 25s on my road bike, but I'm building a long distance road bike that will have the clearance to run 40mm tires if I want. (Probably use 33-38).

Lots of good (but somewhat expensive) tires on the market. But I will say, a good 25 is a HUGE improvement over an OK 25. I think I added about 1.5 MPH just by switching tires. (I'm on Continental GP4000S II, and they are like butter.)

Black wallnut 

I doubt you will notice much difference. A CX file tread tire rolls pretty fast already. Finding the optimum tire pressure for what you have will give you more gains IMHO, which for the road will be closer towards or at the max inflation pressure. Unless your race is on gravel or dirt......

CliffordK

All tires aren't created equally.

High quality narrow tires (is 28mm narrow?) will outperform low quality wide tires.

Of course, lighter isn't always better with respect to puncture resistance.

I've been impressed by the performance of my Clement X'Plor USH 120 tpi 700x35 tires on my Tricross, but don't have any long-term wear data on them. I still think my road bike will outperform that bike, but it may also be a combination of factors with tires only being part of it.

Anyway, you may well be able to find good quality wide tires with low rolling resistance. Nonetheless, I personally prefer 23mm and 25mm tires (for sub 180 lb weight).

chaadster

I'd wager a 28c would help you roll faster (or work less)z than the 35c, and I'd also suggest going to 25c could be better yet.

Just this weekend I was comparing similar road rides on drop bar bikes with similar, high quality tires in 23c and 30c sizes. Both tires are the latest, top-tier tubeless models from Schwalbe, the 23c Pro One, and 30c S-One. For just low- to moderate effort levels at speeds up to about 18mph, they're about equal, but north of 21mph, the 23c were much more eager to go there and to carry the speed.

Both bikes have racy positioning (one a bit more saddle/bar drop) , and share 30mm deep rims, but the 23c equipped bike just wants to roll faster under my 230lbs. Given I've noticed this before between these two bikes, whereas I don't ride 35c tires, I'm pretty confident in the dynamic. I'll swap the 23c wheels onto the othe bike at some point to confirm.

So yes, go narrower, higher pressure for the race:

CliffordK

Keep in mind that not all roads are created equally.

I was out riding today and hit maybe 20 miles of chipseal, along with some good pavement. The chipseal just felt slower, although it isn't showing up on Strava. Still, it was quite a drag to have the constant buzz.

Anyway, tire choice and pressures may be dictated somewhat by the expected road conditions. One can run wider tires at higher pressures under ideal conditions.

Jarrett2

Agreed.

I have a bike with 42's and one with 32's and two with 25's and there is a definitely a speed difference between them. Not as much between the 42 and 32, but definitely a big difference between the 42/32 and the 25's.

I'd say go to a 25mm tire. It will be faster than a 35mm CX tire at the same output. The Continental GP 4000's are a great, smooth, fast 25mm tire. Definitely yank off anything that is slowing you down if you want to go faster, like the fenders and racks.

Ultimately, if you want to be faster, a good road bike is the way to go.

I personally run the 25mm Gator Hardshells just because I ride on terrible roads and want the tougher tire.

10 Wheels

You will like the 28's. Give them a try.

CACycling

Smoother, lighter tire will make a bit of a difference. Well worth trying.

deapee

A 35mm tire will have less rolling resistance than the same tire in a 28mm filled to the same pressure.
A 35mm tire will have more wind resistance than a 28mm tire of the same design.
A 35mm tire will be heavier than a 28mm tire of equal construction and material.

In the end the difference, assuming similar tread pattern is likely to be unnoticeable other than the 35mm tire offering a 'plusher' ride because you will likely fill it to less PSI.

DrIsotope

Anyone who thinks that a few MMs of tire width or a few pounds of bike weight will noticeably-- measurably-- impact their overall speed/performance, is either a top-tier competitive cyclist, or is grossly overestimating their capabilities. I have plenty of KOMs riding a CX frame on 700x32 (that mount to 35) tires. It's not the bike, nor is it the tires. It's the engine.

As the sensible people have stated, the quality of the tire is significantly more important than it's width. A good 28 or 32 or 35 is going to outroll a cheap, stiff 25 (or anything with Gator in it's name.) Stick with your tires, OP, they're good ones.

Jarrett2

Dr Isotope, you are clearly an inhuman beast

OP, if you aren't an inhuman beast and happen to be a mere mortal like the rest of us, you might want to lighten your bike and try some (proven) faster tires to increase your speed.

GravelMN

I've got 25s on my road bike and 32s of the same tire on my hybrid. Even with about a five pound increase in weight and a more upright position on the hybrid, the difference over a 50-mile ride is about 1 mph. If I'm riding with a group the road bike definitely has the advantage for sprints but the hybrid is a more comfortable ride on rough roads. IMHO the advantages vs. disadvantages to the two tire sizes are about a wash.

Erich_E

Thanks for the replies guys!

obed7

way overthinking this... lots of opinions here... and sprint bikes and narrow tires "feel" faster... but the actual numbers are more accurate than feel..
lighter wheels/tires will feel faster, they will spin up faster...but not give any increase in top speed.. how much time do you spend accelerating?
On my bikes, I have 35, 28 and 25 tires....and my avg speed on the bikes is always about the same...varies more by riding conditions than tires or bikes.

chaadster

So is the assertion that we can increase tire width and weight indefinitely, without penalty?

That should be clearly absurd to everyone, so the questions are really about at effort level, for what duration, and at what speed, do we begin to notice the differences.

No doubt if you ride slow and easy, the differences between a wide tire and a skinny one will not be noticeable in terms of effort/duration/ speed. If, however, you ride hard and fast, small demands for increased power will accumulate and accelerate fatigue over time, and aero drag will increasing exponentially with increased speed.

As for engines, well a good one is a good one, but an S&S X-Wedge in a Big Dog Wolf is still a very different experience from that engine performing in a Morgan trike. Suggesting "the engine's" output cannot be optimized for specific results should also be plainly absurd. I'll happily eat my words when a knobby fat tire bike makes the winning time in the TdF Individual Time Trial!

IceNine

Other factors to consider are how well the wheel/tire dampens road noise, how much flat protection they have, how durable they are, and how well the tire protects the wheel. There is a trade off. The narrower the tire, and the more weight the tire carries, the higher the air pressure that is required. A heavy rider could damage a wheel if the wheel isn't made for a heavy load, and a narrow tire will contribute to that risk. Since I struggle with repetitive stress issues in my hands, and because I don't want to stop and change flats when I am in the middle of a ride or on the way to work, I like to use cushier tires with flat protection, usually with the pressure low enough to give me some decent shock protection. But I usually ride alone, and if was trying to keep up with a group of riders my priorities might be different.

Willbird

Well the reason for bigger tires is to be able to run lower pressure.

The ongoing Silca test series is pretty illuminating.

https://silca.cc/blogs/journal

Tire inflation pressure far outweighed many other factors often thought as very important.

The rougher the surface gets the more efficient wider/taller tires at a lower inflation pressure are. Those articles have me running lower pressures already, and enjoying the benefits of increased comfort on chip seal. 90psi is much nicer than 110.....gets me back on a few roads I had written off.

Sure there are limits to everything ....but the 19-23 tires are pretty much "done" for most riders....and specially done are bike designs limited to ONLY those sizes. Choices are good :-).

nfmisso

One thing not mentioned above is different sizes front and rear. On a standard bike, 60% to 70% of the weight is on the rear wheel, it make sense on pavement to have a narrow front tire, which will make the bike more responsive, and feel faster - though I doubt there is any real speed difference.

One of my commuters has 28-622 tire on front and 35-622 on the rear, another has 32-559 front and 40-559 rear. Pressures are the same front and rear. The wider and taller rear tires provide a bit more cushion.

10 Wheels

You should Like the 28's much better from the 35's.

I started a 4200 mile tour on 35's and hated them as they soaked up my pedalling energy.

Became most happy when I put on 28's.

GerryinHouston

Been there, done that... Swapped the 35 mm Bontrager H5s on my Trek Verve for Gatorskins 28 mm. Being in the 250# range, I have to run the tires near the top of the recommended pressure range. There is practically no difference in the effort or speed, only a much harsher ride at 110 psi for the Gatorskins.

I enjoy better the 32 mm Schwalbe Marathon that came OEM with my Randonee.