Mtracer

Yes, with my massive power, when I do a sprint, the tires are smoking I wish.

I'm heavy by cycling standards at around 200 lbs. I'm not especially powerful so I know it's not becasue I'm really stressing the tires there. I do a fair amount of climbing and descending, with the necessary braking. I don't skid the tires when braking, but still slowing the bike with brakes means slowing it with the tire and that's putting stress on the tire. So, flat riding versus descending?

For me, I generally wear out two rear tires and one front in a year. I tend to ride the same bike for 95% of my miles. Though again, the front is almost always due to cuts. I doubt I've ever wore out the surface of a front tire.

That's not been my experience with GP 5000 S TR tires. But, I've only used them on two rim models. But in both cases, they can be done by hand, though I still use levers just to avoid unnecessary effort.

I used to use Specialize Roubaix Pro 2Bliss that were just about impossible to mount and unmount. But that was on different rims. So, no idea if it was the rim or the tire or a bit of both.

eduskator

Some tire / wheel combo are horrible indeed.

I installed a fresh set of Pro One on my new rims (Roval Rapide CL II) yesterday morning and although they were tight as hell to mount, I was able to do the job with no tools. My thumbs are numb today, but that's just a detail.

Good news is that they inflated (I run tubeless) without the use of a compressor, and they're still inflated today even if there's no sealant inside.

surak

Note that the Rule of 105 isn't a hard and fast rule, and that it's calculated based on the measured width of the tire, not stamped width. So a 32mm tire on that Roval's 21mm internal width rim may or may not expand beyond what the "rule" would recommend, but it also may not matter much anyway.

If you don't have issues running 28mm on the front, then I would suggest just sticking with it. But a 32mm probably is fine. Try it and see for yourself; tires are wear items and you can always go back to 28mm later.

PeteHski

Definitely worth a first hand test. It certainly won’t be a disaster and if you don’t feel any improvement then you can always go back on the next set.

choddo

I know i’ve said it before but everyone should own one of these. I couldn’t get a GP5000TL on without it. Was cursing the things. I still can’t get a TR on by hand, even though they aren’t quite as tight, but this thing makes it easy.
https://tyreglider.co.uk
(probably no good for hookless rims though)

FL_Gator

Thanks for all the feedback everyone, I partially chickened out… I’m going to try 30mm front and 32mm back hoping for the nicest balance of speed and comfort for my region and goals. Either way both front and back should feel improvement over the 28s and then my super wide front rim will have some pore protection in case of a flat. Thanks!

PeteHski

I’m sure it will be fine. Let us know how it feels.

FL_Gator

This is awesome, just ordered one, thanks!

terrymorse 

Rolling resistance is only lower on the wider tires when pumped to the same pressure as the narrow tire, which of course nobody does. Wider tires are used at a lower pressure.

PeteHski

See the RR comparison at recommended running pressures. The wider versions are still slightly faster rolling.

terrymorse 

Based on the pressure recommendations from rollingresistance.com, yes. But those recommendations seem a bit of a wag.

Here is the RR comparison for pressures recommended by the Silca calculator, for a 190 lb rider+bike on new pavement (RR linearly interpolated):



Under these conditions, the 25 mm tire wins out.

PeteHski

Either way it’s a wash for rolling resistance on the drum test and if your roads are not perfect then the advantage will swing more significantly in favour of the wider versions. I notice this on group rides when we hit rough road sections (chip seal). The guys still on narrow, high pressure tyres visibly struggle and sometimes even get dropped. On the smoother roads there’s really nothing in it.

The real advantages for wider tyres are better ride quality, better grip and as a bonus for those running tubeless, better flat protection. It’s a no-brainer if you already have wide rims and frame clearance and ride on mixed roads. The one-day classics are a good example in the pro peloton. 30 and 32 mm are now becoming popular for those events.

I get it, you are light and focused on pure climbing on presumably good quality roads. So the above advantages probably don’t matter much. But the OP is 200 lb and riding on mixed quality roads.

Dave Mayer

Continental Grand Prix 5000 S TR 25, 28, 30, 32 mm Comparison (bicyclerollingresistance.com)

The results of this excellent test is that the 25mm tire pumped up to max rated pressure has the lowest rolling resistance of all the sizes tested. This test was done on roughened drum surface to simulate actual pavement. The 25mm tire was also 70 grams lighter than the 32, and obviously has a lower frontal area and therefore was more aero.

Regardless, the RR range difference between all of the tires tested was a trivial 2 watts, or much less of an effect than if you dropped your stem by an inch. The aero disadvantage of the fat tires wasn't tested here but likely exceeds that of any minor RR differences.

So do you want speed or comfort?

PeteHski

Spin it how you like, but running the 25c tyres at their max rated pressure is not likely to be a good idea for either speed, comfort or grip. Remember the Silca data showing how much more you lose if you go 10 psi too high vs 10 psi too low around the optimum for real road conditions? It was 10W vs 1W penalty. That’s why nobody recommends running max rated pressure. It’s just shooting yourself in the foot.

Aero on the wide rims the OP is using (see the thread title) was probably optimised around 28c tyres, so I very much doubt 25c tyres would be an advantage. The external rim width is 35 mm on the front wheel. Moving up to 30 or 32c might be a minor aero penalty, but I very much doubt it would be disastrous.

genejockey 

EDIT: I don't know about you, but I don't ride on a roughened steel drum.

asgelle

Since the test doesn't include impedance losses, it doesn't simulate riding on actual pavement.

PeteHski

Yes and they make it clear in the results that they recommend running lower pressures on average roads. 80 psi for the 25c version in this case. They only suggest running above this on very smooth roads. The OP has already stated that the local roads are rough and worn.

FL_Gator

This was my exact thinking and makes the most sense from a practical application standpoint.

Dave Mayer

?? It is a roughened drum to simulate roughened pavement. Look at the pic of the test rig - I would not want to ride on pavement like this. If the profile on the drum was even rougher, then you wouldn't be on Conti 5000 tires, but 2" MTB tires.

Impedence losses? As in inefficiencies due to rider bouncing around causing rider fatigue, pedaling inefficiencies and tire slippage? The tires in this test are plush enough and have enough vertical compliance well before the rider is bouncing around. Besides, on most gravel, if you go fast enough you just plane over the small stuff.

I get to test a lot of bike gear; today was an almost full day on gravel on a new big-brand bike with 32mm tires and Ultegra hydraulic discs. This rig was heavy and slow.

genejockey 

Geez, dude. That's not even has harsh as paint stripes.

Dave Mayer

OK, I don't live in the third world, sorry. The roller reminds me of chip seal in Alaska.

At our annual gravel race with Cat 5 to 1 starts, everyone is on 25mm tires pumped hard. So no change from their road rig. Sure, it is a little bumpy, and there are always flats, but the rider rationale is if I'm riding on heavy, comfy tires then I'm not going to finish near the front.

tomato coupe

Your claim is not believable.

PeteHski

Maybe it was just you that was slow.

genejockey 

Maybe he is subject to different laws of physics than everyone else.

genejockey 

Indeed. I'd imagine it that were so, some bright person would run 25s at high pressure in some national level gravel races and clean up, while everyone else is slogging with their wide tires and their traction and absorption of bumps.