Champlaincycler

I bought my Robaix a few years back and was told it would take up to 28mm tires. Finally got around to putting some on and the difference was just incredible. Feel like I'm rolling so much better, lower pressure is real comfortable, feels faster although don't really know if thats true. One holdup is that the front tire barely clears the frame, had to let a little air out so it didn't rub. Still, when the tire picks up grit/sand, I can hear it getting rubbed off by the frame/top of the fork. Probably not so good for the long term. What I'd like to know is whether there are 28's around that have a lower profile than others or should I just go back to a 25 on the front. The 28's on there now are Continentals.

Thanks

CliffordK

There would be no problem riding 25 in front and 28 in rear, other than not being able to rotate a worn front to the rear.

I'm seeing a Specialized S-Works Turbo Tire listed in 22mm, 24mm, 26mm, and 28mm sizes. I haven't seen one, but perhaps it would be worth looking at.

The Challenge Paris-Roubaix Tire (120TPI or 300TPI) are listed as 700x27c.

Oops, never mind on the Challenge tires. According to this page, they were the largest ones he measured.

28mm Tire Shootout - Slowtwitch.com

Ok, tire size seems to vary tremendously depending on the rim choice. That may be an option is to try your existing tires on a narrow front rim.

Here is another comparision that I found.
https://www.bikeforums.net/road-cycli...michelin.htmlv

Vittoria Rubino came in as the smallest.

Also note, the tires apparently stretch a little over time, so a barely fitting tire could become worse with time.

Eric S.

I bought a set of inexpensive Continental Ultra Sport tires and they run big (maybe tall is the correct term). I've been riding Serfas SECA tires in 28 for a few years and they fit all my bikes, the most current one a 2004 LeMond Buenos Aires. I can't use the Continentals on that bike.

If you're open to trying something else, Serfas may fit the bill.

Champlaincycler

Thanks ,

Maybe I should be looking for 25's or 26's that run big. I just love the feel of the 28's though. Little disappointed that Specialized would market these bikes as accepting up to 28's when they may or may not. Its still a pretty nice ride though.

dabac

Tire widths is well known to have a certain "drift" in it, don't blame the bike manufacturer. You're better off pointing the finger on the tire manufacturers.
And I think you overexaggerate the risk of marginal clearance.
The studded tires on my commuter runs tight to the fenders.
But for probably more than 10 000 miles, all that has ever created is quickly passing noise.

My MTB once managed to pick up a pine cone and pinch it between rear tire and brake bridge. That did indeed cause an unexpected wheel lock.

trailflow1

I've never tried it but i have read of people adding some kind of spacer material to the dropouts, so to nudge the wheel away from the frame and fork. It could give you an extra vital 1-3mm of clearance. This would only work on QR frames and forks.

What exact material they used im not sure, but my idea would be to glue rubber pieces to the inside area of the dropouts.

You would also need to account for moving the brake holders further down the brake arms.

CliffordK

An opposite tactic might be to add something like propeller/helicopter tape to the bottom of the fork crown to provide a minimal amount of protection, although it would decrease clearance slightly/

ThermionicScott 

@Champlaincycler, it does suck that your Roubaix can't accommodate all 28mm tires (and 28 is the smallest I use on any bike), but all is not lost. What pressure do you typically pump to? If you are not particularly heavy, you may be able to use less pressure in your 25's than the max listed on the sidewall. Search for "15% tire drop chart".

Champlaincycler

Thanks TS, that's what I was planning on. I'm 190 lbs, could probably soften up a 25 on the front to 85 psi or so. No big deal as I've ridden 25's for the last few years but had no idea how much of a difference 28's make in ride quality. Its still a great bike.

ThermionicScott 

Here's a copy of that article I had in mind. I was on my phone earlier, so not as easy to dig up and post links: https://www.adventurecycling.org/def...SIRX_Heine.pdf

canklecat

I'd like to try 28s on my Centurion Ironman but I doubt they'd fit. The original tires were 700x18 and while there's plenty of room for the 700x23 tires on it now, 700x25 would probably be the maximum since some manufacturers vary quite a bit from nominal specs.

The cheap Vittoria Zaffiros on the bike now have only a mediocre rating from the rolling resistance review site, and much worse with pressure below 120 psi. Yet I have noticed that lowering the pressure doesn't seem slower and it's more comfortable. I'm wondering whether the reality of riding on chipseal and bad pavement makes those rolling resistance tests irrelevant to some real world conditions.

We don't have many long stretches of good smooth asphalt to test the theory. There's a nearby neighborhood with some smooth pavement for up to half a mile at a stretch, so I might experiment with various pressures. But I'd need to repeat the tests over a long period to even out the influences of my own so-so conditioning.

Anyway, I'm waiting for an order of Continental Ones with V Guard in 700x23 to see how they feel compared with the Zaffiros. I'd rather have had the 700x25, but Jenson had the 23s on sale cheap.

CliffordK

Many of the rolling resistance tests are being run on diamond plate, I think, to simulate rough riding conditions.

I'm surprised they don't just build a rig to tow around on roads at 25 MPH or so.

canklecat

In my case I'm not expecting tires to magically make me faster. I already know from trying various wider tires on my hybrids that I'm faster when I'm more comfortable, so a tire that doesn't tire me out will be "faster" over the long haul.

However I would like to find a road bike tire that will help me at least equal my best times on my hybrid with 700x42 tires over rural chipseal and rough roads. So far the road bike is faster only over smooth asphalt and hill climbs, since it's lighter.

XXLHardrock

I'm using 28mm GravelKings and am really pleased. They roll way nicer than those Flinstones -wheel- quality Gatorskins. They measured 26.5 on the stock 19(?) mm rims and an impressive 28.7 on the Son Plus Archetype. My $0.02 (Canadian)

rumrunn6

or take an angle grinder to the bottom of the fork crown to shape it a little concavely giving you another mm or two of clearance

CliffordK

Is the crown carbon fiber or aluminum?
Solid or hollow?

I don't think grinding the crown of my carbon fiber road bike would be my first choice.

rumrunn6

right of course. I did that to an old steel bike this winter to get some fenders to squeeze in. eventually cut the fenders so the grinding was ultimately unnecessary

Grand Bois

A few strokes with a half round file worked for me.

XXLHardrock

How much clearance is considered enough? I imagine front would be more crucial than rear. I can almost fit a 32 gravelking in my Defy's fork. Almost.