Does anyone have tire width measurements for 32mm GP5k TR on ~22mm internal width hooked rims? I suspect they’ll inflate true to size since 22mm isn’t really out of the ordinary anymore.
It reduces some kinda of flats. It increases others.
Lower pressures are slower, variables being kept equal.
The advantage of the larger tyre is a better contact patch for cornering and braking grip, and a larger air cushion to reseal tubeless holes.
In some situations with very poor roads, a lower pressure will exhibit lower overall loss to the tyre/road interface (note I didn’t say rolling resistance, because the RR is higher but the impedance loss is lower).
It’s Def more comfortable tho.
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I’m currently of the train of thought that better surfaces and faster speeds exert a downward pressure on the optimum tyre size, while poorer surfaces and slower speeds point towards wider ones.
In my case, the semi-rural roads of Herts, Beds, Bucks and Oxfordshire are often quite poor in quality. In the summer, I might average 35-37kph if I join the A group for some evening loops, but most of my riding is going to be in the 28-32kph range. My understanding of the current thinking is that in that 28-32 range, there is likely to be little to no speed difference between a 28 and a 32 (probably even a 35 if it would fit), but there will be advantages to the wider tyre in grip, comfort and puncture resistance. In the paceline, there probably are small aero losses, but it’s such a small part of my riding, it’s not worth worrying about.
Others may have different views and that’s totally cool, but IMO when you’re quick enough to worry about these kind of differences (like the AXS 10t argument), you’re probably quick enough to be riding what your sponsor gives you (or at least heavily subsidises). Even on that note, the fastest rider I know is planning to be on 30s this year…
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I wouldnt mind hearing how you find it. I typically wont get to ride outside till late April so lots of time for me to dwell on it.
A random gripe but I kinda don’t like Zipp’s new logo 
If it helps, that chimes pretty well with my experience on the equally poor road surfaces of Surrey and Berkshire! Over last couple of years I’ve run various bikes and wheelsets with tyres from 25 to 32mm and 45 to 90psi. If it’s a cruisey 28-32kph ride (solo or group) then I’ll take wider and lower pressure every day of the week, there’s no noticeable downside and if anything maybe a speed benefit on rougher sections or if the ride is long enough that the increased comfort leads to less fatigue.
But I also race and do fast group rides (on routes chosen for good road surface) where the average will be 40+kph, and in those cases I definitely find a noticeable penalty from wide and lower pressure tyres. I think the optimum for riding fast on decent UK surfaces would be 28s (or maybe 28 front, 30 rear) run at the higher end of the recommended pressure, on wheels with wide enough rims (30+mm) to adhere to the 105% rule for a good rim-tire interface. Unfortunately I don’t currently own a set of wheels with rims that wide! My widest rims are 27mm and with a 28mm tyre it does noticeably bulge out wider than the rim. So I tend to race 25mm unless I know it’s a course with bad road surface in which case I might use 28mm (or just not enter…).
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Whats the max size anyone has managed to fit to an SL7?
From another thread I wrote this:
I’ve got an SL7 and no problem with 32c tires that on wider gravel wheels measure out to 34-35mm. I’ve used both Pirelli Cinturato Velo TLR in 32c (measures out to 34mm) and Specialized Roubaix Pro 2Bliss 30/32c (measures out to 35-36mm). Measured width on Roval Terra gravel wheels with 25mm internal width. The easy gravel out here is mostly dirt roads with some rocks.
After about 500 miles the Roubaix expanded a bit more, and while riding to pick up my bib for an event I stood up to get thru a traffic light and 800+ watts made the tire rub against the chain stay.
Had 3-4mm of clearance at chain stay after initial install of Roubaix when they measured at 36mm.
BicycleRollingResistance measured the Roubaix Pro 30/32 at 31.9mm on wheels with 17.8mm internal width. They measured 36mm on my Roval Terra wheels with 25mm internal width. Basically 32mm on old school wheels, and 36mm on wide gravel wheels. Pretty big difference.
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I have been running Challenge Strada Bianca for the last year or so. I have 2 sizes, 36mm and 45mm. I got the 45s on the bike when they were released and now I no longer ride my 650b bike. In fact it is now my trainer bike (used to be my primary)
I don’t know if I will fit the 36s this year unless I end up doing STP and even then I might leave on the 45s. the 45s work exceptionally well on road and gravel. I keep up with the folks from my cx team on team gravel/road rides.
I ride a 56cm Lynskey GR270 with titanium fork
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How did you like the Specialized Roubaix 2Bliss 30/32, apart from the clearance concerns?
I’m doing a 75mi ride in late April that has a few gravel sections (some a bit rough)…guessing 85% (less than pristine) tarmac and 15% gravel. I’m running Vittoria N.EXT now and like them, but was thinking a little more volume of the Specialized tires might be worth losing a few watts. Bike is a Roubaix Expert with advertised 33mm clearance and 23mm internal rims. I think I could fit a measured 36mm tire with 4mm clearance left all around.
Liked them a lot, better than the Pirelli Cinturato. If the rear 32c N.EXT is flat prone, I’ll mount the one sitting on the shelf, but this time on a 21mm internal width rim as that should reduce the expansion and allow fitting on the SL7 rear wheel. Can’t beat the price at $37.49 right now (ExcelSports). @FrankTuna read the reviews on Specialized website. Of note for the SL7 - several “measures to 34mm on 20mm internal width rim” comments.
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I’ll be curious to get your thoughts on the N.EXT vs. Roubaix 30/32.
As per the other thread, I’m running 34mm N.EXT and I’m generally happy with it but I’m always on the lookout for my next set of tires. The Roubaix has always caught my eye. Per BRR, it rolls slower than the N.EXT but the puncture resistance is better.
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My current tires still have 500-1000 miles left, probably looking at late March before putting the N.EXT on the bike. I might install the Roubaix Pro on 21mm internal rims with an inner tube, just to see the external width.
I absolutely prefer the Roubaix over the indestructible Cinturato, however I only had the Roubaix on rear tire for 404 miles (about 3 weeks), and the front tire for 1250 miles, maybe 9 or 10 weeks (?). Enough time to form an opinion, but not enough for long term testing.
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I have a couple of thousand kilometres on my Roubaix 33. On a 25mm inner width wheel they measure 34.9mm set up tubeless. While they are not as fast as a GP5000S TR, or 34mm PRO ONE, I use these for multi day rides and light gravel rides because they have a 31mm wide tread, which I prefer for wide wheels, and good puncture protection, and still nearly as fast as a PRO ONE or CORSA NEXT
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@widerisfaster User name checks out 
Going to give these a shot, especially since they’re on sale ~$38. Thanks!!
Yup, I’m a believer!
Went to 28mm for road in 2016, and 31mm WAM in 2020. DOnt see myself going back to anything skinnier.
For mixed surface rides I have ridden 35mm, 38mm, and 44mm tyres, and while there is an aero penalty of about 1W for each extra 2mm of width at 30km/h, larger sizes open up some great route options.
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So, dropping pressures to c.40 psi front and 43 rear has the front starting to feel just a little soft under hard cornering and the bike just a hair more sluggish. Comfort is superb, though.
I’m a big fan of the gp5000, and think they will be my go to tyre from herein, but my sense is 30mm is the sweetspot for the riding I do and my local roads. I think 32 edges 28, however…
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Sheet!. I have these in 32mm in my road wheels and love them. Didn’t know 34mm existed!
I’ve got about 200 miles and 10 days on the N.EXT:
- 28c front, measures 30.4mm on 21mm inner width rim
- 32c rear, measures 34mm on 21mm inner width rim
Like these better than the Roubaix 30/32, will see how well they hold up with all the road debris.
Prices on the Roubaix have been down around $38/each the last month or two, however I got the N.EXT for $54 each.
How are things with your 34c N.EXT?
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