This is a common complaint people make about tyres.
What is “Supple”?
RR is inversely proportional to sidewall compliance. The fastest tyres have the most compliant sidewalls because this is how hysteresis loss is reduced. GP5000s are faster than, say, S Works Turbos and they have more grip. In fact, you could run a gp5000 at a lower pressure than a turbo for the same rolling resistance and get even more grip and even more comfort.
My gut says it’s inconsistency when inflating tyres - or incorrectly assuming that “28c” in one tyre is “28c” in another - and so 80psi in a t2/t5 might actually be 90psi in a gp5000 because the 5000 comes up large. This is why the silca calculator asks for measured width not stated width.
Wondering how the staggered setup feels wondering if I should go 30c front and rear or 28c fr, 30c rear on my SL8 Pro with Rapide wheels. 28c would have a little weight and aero benefit but wouldn’t be worth it if it affected handling or made things weird, I understand it would slightly reduce comfort.
To me, the 26c front on Tarmac SL7 with Rapide CLX (1st and 2nd get) feels a little squirrelly because of road debris. I definitely prefer 28 or 30 or 32 on the front, and the tires are still narrower than the 35mm external rim width.
For me the back tire is more about flat prevention. With the 1st gen Rapide CLX (tube only), I definitely found that 32c tires would get less flats than 28c. With a 28c tube tire, I was getting a flat every 2-3 weeks because our roads are littered with thorns (goatherds) and screws/nails that fall off trucks of constructions workers (this area has seen new housing developments for 20 years).
No issues running staggered, it’s all fun just like my previous car (BMW 535 staggered rims and tires). And as to tire width, I recently set a KOM on a shorter ~0.3 mile / 0.5km segment at almost 32mph on my Checkpoint gravel bike with 42c S-Works Pathfinders. Coming back into town I had a nice tailwind and was holding 29mph for 3+ minutes, but was solo and working for it around 110% threshold. The cool thing was I was floating over the crap road on those big tires, and on the Tarmac the 32c GP5K AS TR also provide a fair amount of float on crap roads at speeds above 22-24mph.
True, I thought the wheels were optimized for 28mm… I think you would need the tire to blow up to 33.5 to get the rule of 105. Maybe I should just go 30/30. For some reason was thinking 28mm in front would be more aero at the sacrifice of comfort but maybe not with the Rapides…
At launch Specialized stated the Rapide CLX (I and II) are aero optimized for 26c Specialized tires. FWIW I read somewhere that Specialized told a tester (that experienced and reported it) that 26c front on those 35mm Rapide CLX will get pushed around a bit more in crosswinds, while 28c won’t. And then you have NorCal cycling’s non-scientific test where 32c were faster. So “what’s the fastest tire” really depends on real-world aerodynamics, tire/road surface impedance, and the tire’s rolling resistance on that particular road surface. None of which you can predict on a steel drum, so take the BRR testing with a grain of salt.
Just as a heads up, had inquired with Tufo about whether they would be offering their Comtura 4 TR in a 32c or 34c in the future and how the new Endurance 7TR compares to the Comtura 4 TR and when it might be tested by Bicyclerollingresistance.
This was their reply:
‘In future we plan 32. 34 not yet.
Endurance is better in every aspect. It is brand new evolution. Should be tested in 2 months…’
The Comtura 4 TR compares well to Mondo, P Zero 4S TLR and Corsa Pro Control but with better puncture resistance in 28, if it was available in a 32-34c I would be using it as my commuter tire, sounds like the Endurance 7 TR may be even better though!
ok, have a pinhole leak in the AS TR 32c rear tire. Annoying me for 3-4 weeks now. Mileage:
1341 miles = 2158km
Posting that pic because I keep saying “almost 1700 miles” in various other threads, but 1700 miles is for a tubed version of the gp5k still sitting on the shelf.
Last week before riding the tire was flat, twice, so I removed it. No more sealant inside, but a beautifully coated interior (peeled right off in 2-3 minutes).
Took about 3-4 weeks for ~20ml of Orange Seal to leak out.
After removing the tire I can’t find a wire or pinhole on the inside. WTF!
I know exactly where to look, because there is always some dried sealant that oozes out overnight down the sidewall. Clean the tire in the evening, and every afternoon would find freshly leaked sealant on the tire. Wipe the tire dry, squeeze the tire a bit, and I could see sealant start to bubble out. Was at the LBS first time, and they saw the same.
Pretty disappointing after 1341 miles.
This AS TR slow leak, along with the Mondo (full story on that below) are “unpatchable” slow leaks as I can’t find any wire or pinhole on the inside. Guess I could try patching a larger area on the inside.
Last week I decided it was time to try out the 28c since there I can’t find a hole to patch.
Rode last night for ~100 minutes and was unhappy with the 28c GP5K All Season TR. Was getting bounced around, rough ride. Life is too short to get beat up on training rides.
Long story short - I’m saying “no” to the 28c AS TR. And in general, I’m done with optimizing for aero and getting beat up on training rides.
Henceforth I’m rolling with 32c rear tire on the Tarmac SL7. That includes the 32c AS TR when I can pick one up for a good price.
BTW, this was never an issue.
Next topic.
An update on my Mondo mystery…
After replacing the Mondo with the AS TR, I noticed a LOT of “stuff” in the bottom of the Orange Seal bottle. Tipped it over for a couple days, kept shaking it, only to discover the bottom had been filled with glitter. Doh! That glitter helps seal leaks, therefore I now believe my sealing problems with the Mondo were due to my own pilot error. Live and learn.
Oh, and when installing the AS TR there was plenty of glitter in the tire.
Reinspected the 32c Mondo had those 2 needle punctures, and also a rather large hole from a chunk of metal or screw or nail. Wanted to give these another try, will patch the inside and see how it goes now that I’m certain the Orange Seal is well shaken before dispensing.
My 5000TRs developed what you might call a pinhole leak, but at a far higher mileage. I could pump them up to 80psi and 30 mins or more later whilst sitting in the stand psst and they would spurt sealant until they were around 50psi. Not pumping them to much over 50psi seemed to stop it but bizarrely not using the tyre over winter seems to have fixed it entirely and its easily taking 70 psi
Did you try to find anywhere you could stick a plug into where the sealant was leaking? I’ve had similar pinhole leaks, can’t see a hole but if I probe around with a plug I’ve been able to find where the sealant is coming out and push a plug through.
I haven’t tried the AS TR yet, though was going to give them a go next time I need a new tyre on my winter/beater bike. Currently using the Corsa N.exts, generally happy other than that Vittoria say that plugs should not be used with them as a permanent fix, and that’s also been my experience - something about the tyre compound means it simply doesn’t bond with plugs the way other tyres do, so a plug will get you home but then you still need to repair or replace the tyre. Whereas with other tyres the plug has bonded in such that a few rides later I would struggle to even find where the plug was.
My conclusion with mileage, durability and puncture resistance is that there’s quite a bit of luck involved, and maybe also some variation in tyres from batch to batch (or from year to year even if the manufacturer doesn’t announce any changes). When I first tried the N.exts I had 2 separate bad front punctures that wouldn’t seal inside the first few hundred miles. Second one was on the sidewall and nothing I tried skulk sort it so threw that tyre in the bin in disgust and put a different front on, thinking I would change the rear as well at some point. Never got round to changing the rear N.ext, it clocked up thousands of miles on crappy roads in all weather with no issues at all, such that when it came time to change both front and rear (rear was getting square at this point!) I went with a new set of N.exts front and back and they’ve also been great. So maybe that front was either just from a bad batch or I got really unlucky with 2 super sharp objects the likes of which I haven’t encountered since.
No, even put it under a large lighted magnifying lens that I use for electronics. Bizarre. Honestly don’t understand what happened.
The Vittoria N.EXT 32c measure 32.7mm on 21mm internal width wheel. A little less than the GP5K AS TR. Didn’t get beat up last night, felt good and a little different versus the AS TR. My experience with the N.EXT - one time I pulled out a construction staple and it sealed immediately. Last year it was almost impossible to remove the 28c N.EXT when it was time to replace, the bead didn’t want to come off the rim seat.
I got a lot of flats from broken glass last year. I went to tubeless on my nice wheels (rim brake bike, so I spend a bit of the start and end of the season on training wheels).
I’d always run GP 5000s. For something different, I ran Vittoria Corsa Pros. The tan sidewalls provide a clear benefit to time to exhaustion (that is, a placebo effect). However, tan walls have been shown to be slower on the Contis. I was hoping maybe the Vittorias would be more comfortable as well - not sure I can clearly feel this. They do lose air about as fast as a latex tube.
So, when they wear out, I’m going to use the GP5000 S TRs.
Just saying…
