garysol1 

Thanks Les....

exime

Contintental GP 4000s ii 25c are on sale for $34 on amazon so I'm going for it.

exime

I just found a few articles that say if you use wheels with (17.5mm inner/23mm outer) or similar than you're losing more in aerodynamics and sloppy handling than you are gaining in rolling resistance or comfort. Now I'm considering getting the 23mms GP4000s instead since the 25mm run closer to 28mm and the 23mm more closer to 25mm considering the stock SL5 rims are the 17.5mm inner 23mm outer.

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"If you don’t want to get into the details, here’s my bottom line. For the best combination of minimum rolling resistance, maximum aerodynamic performance and confident handling, order a pair of Continental Grand Prix 4000S II clincher tires online at Competitive Cyclist, eBay Cycling, Amazon, ProBikeKit, Wiggle, Chain Reaction in the 23C/23mm size and pump them up to between 95psi/6.5bar (lighter riders, softer ride) and 115psi/8bar (heavier riders, firmer ride) and use a light butyl inner tube. Don’t use a 25C/25mm size Conti tire unless you have wheels that are 27mm or wider at the brake track and don’t buy them in a physical store where they will cost you at least 1/3rd more."

"Next consider set-up #2, the currently popular 25C or 25mm size Continental Grand Prix 4000S II on that same stock Mavic Ksyrium wheel whose size is common with most stock and many low profile alloy upgrade wheels from Shimano, Mavic, Campagnolo, Fulcrum, Giant, and DT Swiss. Unfortunately, this is where a lot of people with entry-level or first step-up wheels end up when they hear wider is faster and more comfortable. If you want to go fast, the overhang on this combination is an aerodynamic nightmare and handling will also be sloppy, especially if you’ve also lowered the pressure to 80 or 90 psi to make your ride more comfortable."

- https://intheknowcycling.com/2015/05...ad-bike-tires/

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Also this:

"Off-course, what will be won in the rolling resistance department will be lost in the aerodynamics department. I'm not sure at what kind of speed this turnover point would be. This also depends greatly on the tire/wheel combo. A 28C tire on a rim that is designed for a 23C tire will perform poorer."


- Continental Grand Prix 4000S II 23 25 28 mm Comparison

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It seems like the GP 4000 25mm are getting pretty bad reviews on 17inner/23outer rims that come on bikes like the SL5 and I don't plan on upgrading wheels yet.

To me the extra "comfort" is not worth losing more in both handling and aerodynamics watts. I'd rather just bump the 23mm down a few PSI and call it a day. I know I'm not a racer but I train hard and I want to push my limits of speed and cadence this year. I don't want to buy an amazing SL5 to turn it into a sloppy handling bike for a touch of extra comfort.

garysol1 

Sounds like a lot of "bunk" to me. I have yet to see anyone complain after going to a 25c tire from a 23c no matter the rim. Will aerodynamics be effected.... maybe minimally but handling will improve with the more rounded tire profile and the comfort will improve with the lower psi. A more comfortable rider is a faster rider.

exime

I actually got this response from the writer of the article and he just suggested I stick with the 25c.

"Well your stock wheels (Bontrager Race Lite?) aren’t the most aero so you probably won’t pick up a lot of speed with the narrower tires. It sounds like the 25C tires will give you a lot of comfort on the roads you ride so I’d probably stick with those given your riding situation. There are other ways to get speedy without spending a dime more (see here) so try some of those and enjoy the ride. Steve"

JLopez149

For anyone still interested still.. I mounted up some Schwalbe Pro One Tubeless 28s on my SL5. There is plenty of clearance even with the tires measuring over 29mm.

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garysol1 

And to add...... I have run Specialized Roubaix 28's on my SLR with Speedstops and there was clearance...... not much but enough.

cydewaze

Well this has been interesting. I too went with 25mm wide tires after reading that it was the trend. This thread got me doing some research to make sure I didn't have a tire/rim mismatch, and oddly, it looks like the 25mm are on the narrow end of what my rim would like.



My rims are Kinlin XR-22T which have a 19mm internal width. So according to this chart (and a similar, Mavic one), 25 is on the narrow side. So I guess I'm good.

BarryVee

Emonda SL6 Ultegra w/25mm Conti GP4000sII on my Dura Ace C24 rims measure 27mm, (15C on the above chart I believe). I measure top of tire to brake clearance f/r = 6mm/4.7mm. Plenty for *most* of my riding. There is a section of chip coat on the East side of Mt. Hamilton Ca. that can be problematic, especially on hot days when chips stick onto the tires and pull up. Lacking clearance they scour the underside of the fork and brakes plus drop into the chain. There they turn the drive train into a mini-rock crusher, exploding as they grind through the chain ring and cassette. Here's a pic of the chip sealed road surface with a California Newt for amusement.

les_pink

Thanks to all for their interesting posts.
Each to their won, but I have tried 23's, 25's, 26's and 28s, tubeless and clincher on my Emonda SL8 with TLR rims. Each to his/her own, but I found the 28's (Schwalbe one clinchers) a little too large, with the tyres picking up road debris in wet weather and (as in the post above) scouring/scratching the underside of the brake arms (duraace). 26's (Bontrager TLR) were good until tyre failures on the road - tubeless is slightly more comfortable, but a pain in the proverbial to fix on the roadside and a pain in the proverbial to seat in the rim properly. 23's are too hard/narrow on anything but the best bitumen and I find 23's the least capable tyres on fast descents, especially if the road is not glass smooth. My current Schwalbe One's (25's) are more comfortable than the Conti 4000II's 25's I was just running, just as light and seem to be the best tyre for my bike and my riding style that I have found so far.

RNAV

Has anyone been able to fit 28s or 25s with a Sram Red group? I'm currently running 23 Pro Ones, think I've got room for 25s, but don't know about 28s.

GlennR

I have a Emonda SLR, Sram eTap, Zipp 303, Bontrager Speed Stop brakes and Conti GP4000SII 700cx25. Plenty of room.

RNAV

Thanks -- I was more concerned about clearance with the Sram Red brakes. You've got direct-mount speed stops, which if I recall have better tire clearance.

rimarco81

This may be very late,but I installed Continental Gaterskins 700x28 with room to spare. Hope this helps.
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GlennR

Which Emonda, 1st or 2nd generation, rim or disc brakes?

1st generation with rim.. no way a 28mm will fit the front.
2nd generation with disc, sure a 28 mm will fit.

rimarco81

Hello,
Emonda ALR 5 2016. Rim brakes. Installed Continental Gatorskins 28mm on both front and rear Bontrager stock rims. Of course must deflate tires to remove rims from bike. Clears exactly 4mm of space from the seatpost. Wasn't very sure about the clearance but my bike shop wouldn't install them if it wasn't safe or feasible. I'll send pics is you would like.

Good luck.

jwalther

Hoping for some real world experience. . .I'm looking at some used Dura Ace C40 tubulars for my 16 SLR with the Bontrager direct mount brakes. The wheels have 28c Vittorias glued on, and I'm doubtful they'll fit. Anyone running C40s with wide tires?

les_pink

For what its worth jwalther... I have a 2016 SLR with Bontrager direct mount brakes. DeCADENce clinchers (19.5mm internal, 27.5mm external). Running Vittoria Corsa G2 28c tyres. Plenty of space front and rear with that combo. The new R9100 C40 tubs look nice.