ilovecycling

I also agree that the Lugano's suck. My gf has them on her Litespeed M1 (from competitive cyclist), and they ride like absolute crap. They are noticeably slower than pretty much everything I've ridden and the grip when cornering is awful.

I ride 25mm Conti GP4000s and love them. Super fast rolling and a very nice ride. I've also never felt a sketchy moment when corning. I'll probably get the 23's next time though just to see if there is a difference. These were my first ever pair of GP4k's, so I don't know if I like them because they are GP4k's or because they are 25mm.

caloso

The 25mm Conti GP4K is the best clincher I've ever ridden on. Take that to the bank.

WHOOOSSHHH...

I switched from Mich Pro 3's 23's, to Conti 4000s 25's last year on both my bikes. Huge differnce in comfort. Dropped psi from 110 to 95. Also went thru the pro 3's like running water, and still on my first set of Conti 4000's!

libero

thanks for the posts.
I'm a long-time Conti GP4000 user. I converted to 4000S after the vectran introduction and the Contis were the best performers in the neutral German research on tires.
(Tour magazine).

Anyway, can anyone tell me the height difference between 4000S 23mm and 25mm?
I'd like to put a 25mm on, particularly on the rear, as I'm a 90kg rider, but the rear on one of my bikes has precious little clearance to the FD clamp.
If you have an estimate of the height difference, it's best if you can check it when the tires are new, and control for equal pressure and equal rim shape.

I noted that on my rims, at about 110PSI, the 23mm Conti 4000S was actually closer to 24mm wide.

Bike Gremlin

Just physics. If the surface is not such that thread can "bite" into it, there is nothing gained from the thread. It can only make it worse on hard surfaces (try cornering on knobby tyres, then switch to slicks and try - you'll see it).

No, not really. A brick has a very high rolling resistance, but is quite slippery on concrete.

I agree it adds flat protection. However, a protective layer like on Marathon tyres is a lot more efficient in my experience.

I also agree it IS counterintuitive. Just like many other things. E.g. countersteering, or a fact that thicker tyres have LESS rolling ressistance than thinner ones when pumped at the same pressure. But being counterintuitive doesn't make it wrong.

Trsnrtr

I ride Conti GP4000 25s because I'm slightly over 200#. I occasionally run a 28 in the back.

ColinL

Tread design does nothing for flat protection. I will happily show you some cyclocross and MTB knobbies I have that have minimal flat protection both in reputation and my own experience.

Flat protection comes from the design of the tire carcass itself. Specifically:
- presence of puncture belt(s)
- material and thickness of puncture belt(s)
- location/coverage of puncture belt(s) - under tread only, or tread and sidewall
- thickness of the tread layer (slick, grooved or knobby)

Tread thickness is by far the least important. Most tires with robust sidewall protection have a well-earned reputation of being difficult to mount on the rim due to the thickness and lack of flexibility in the tire carcass.

Puncture belts can be rubber, kevlar fabric, aramid fabric, or ceramic fabric. I am no tire engineer but I think the thickness of the belt matters more than the material, excluding rubber. Rubber isn't a great defense against sharp objects...

I end up pitching these in just about every tire thread, but again, I suggest using Mr Tuffy tire liners if you have frequent problems with puncture flats. It's a strip of very thin, very tough plastic. The ultra light liners are 30g each (60g pair) and give far more peace of mind than any tire alone. I've used them with great success in tires that have minimal flat protection and they help tremendously. I can't feel any ride quality difference, but I'm sure it is there although slight.

hhnngg1

You're wrong here. There is absolutely a difference, at 100psi, between 25 and 23c. You're liking using 24mms that are smaller and closer to 23cs.

As I said, my 25cs were thick enough that I had to push them through the front brake system to remove the front wheel - there wasn't enough clearance to just slide through unlike 23cs.

If you actually tried 25cs, you'd agree with me.

badger1

"You're wrong here. There is absolutely a difference, at 100psi, between 25 and 23c." ... incorrect, I think, if you are talking about an otherwise identical tire in the two widths.
I have GP4000S in both 23 and 25. At 90/100 (f/r) in both, there is absolutely no perceptible difference in ride quality (nor would one expect there to be). Ditto at 80/90 (f/r) ... save that one is risking pinch flats on the 23s!
However, the 25s at 80/90 run noticeably 'smoother' than the 23s at 90/100, as one would expect; the difference is down to being able to run the 25s at a noticeably lower pressure, as MerlinEL pointed out.

volosong

Wow! Usually on BF when I have something to say, nobody cares. So, I really haven't been monitoring this thread and have been out riding instead. Just remembered this thread because of the early Monday morning e-mail thread reminders. I'm sorry for not being responsive. Feel free to PM if anyone needs more data. Some more info on my experiences...

The original MIchelin Lithion II tires were purchased from a LBS and mounted on a set of Dura-Ace WH-7850-C24-CL wheels. Until I built up the Pinarello, I used the wheels/tires on a Kestrel RT800-SL and a Trek Madone 4.5, both model year 2010. The Kestrel has a fairly aggressive geometry and the Trek has a more relaxed geometry. I use the Kestrel as my go-fast flat land bike. It was built up with D/A components. The Trek is my hill climbing and long distance/century bike and built up with Ultegra components. I swapped the wheels back and forth to each bike as needed. I always ran at 120 psi. I am 6'3" tall and weigh 205 pounds. I was very, very happy with the ride/performance/handling of the D/A wheels and Michelin tires when at 120psi, on both bikes. No complaints at all.

When I built up the Pinarello with D/A from the Kestrel, I moved the wheels/tires across also. I have tried riding with 120psi, 110psi, and 100psi. No difference in ride quality. It was awful! Every little bump in the asphalt sent jolts throughout the whole frame. It was no fun riding that bike and I had even considered selling it. Tire pressure didn't matter. (Almost all of my riding is on open asphalt roads here in the high desert. Minimal stop signs and signals. A typical ride would be between 20-40 miles, riding solo, fairly flattish with only a few hills depending on the route, sometimes quite windy, normal moving averages are between 15-17 mph, hardly ever faster, rarely slower).

Last year, I got a slice in one of the original tires on the Trek and went to the shop I purchased the bike to get a replacement. I wasn't too particular and he gave me two Bontrager 700x25 Select-K tires. I never mounted them because I stopped using those crappy Trek OEM wheels. One day, I decided to try 25 tires on the Pinarello and before going out to purchase a set, checked these Bontrager tires to see what size they were. They are 25, so I tried them on the D/A rims and put them on the Pinarello. The maximum pressure is 100psi, and that is what I use.

Note: I have since built up the Kestrel with Ultegra, (having moved the D/A to the Pinarello) and put the Lithion II tires on Ultegra wheels for the Kestrel. It rides sweet. There was just something about the Lithion II 23 tires on the Pinarello. Just wasn't a good combination. Maybe other 23 tires would be okay, maybe not.

MajorMantra

Not trying to drag us OT, but...

This is perfectly true if we're talking about mtb style treads or the pointless swirly patterns that Conti and others put on their tyres for marketing purposes, and surfaces that are perfectly smooth. I do think it may not be the whole story though. Real tarmac road surfaces are not glassy smooth - if you inspect them closely they are a mass of tiny cracks and bumps so it is at least conceivable that a very fine pattern of raised knobs or ridges (like the Vittoria Rubino, perhaps) could increase the size of the effective tyre/road contact patch.

Of course real road conditions vary a great deal and road cyclists are probably best served overall by a slick, soft compound for the best trade-off of maximum grip and speed.

pennstater

Did the same. Huge difference in comfort, wear and flat resistance. Did not notice a difference in performance. Be advised that I am 250 so I am running 115 front/120 rear. I believe the wear and flat resistance only applies to the black 4000s.

I could see how lighter riders may not notice a significant change in comfort. My wife still rides Pro 3s in 23, but at 95 front/100 rear. That's already plenty comfortable.

SlimAgainSoon

To draw the most benefit out of a switch to 25s, you'll want to run with slightly lower pressure.

The slightly larger volume of 25s over 23s allows this, so take advantage of it.

kc0yef 

ON my litespeed I can only fir 23 on the front and 25 on the back wish I could get a 25 up frnt but that would be a new fork... I run 120 front and 110 in the back it is comfortable enough and fast I weigh 260

FunkyStickman

I put 40's on my bike and the ride was nothing short of awesome.

Lol.

(edit) Thinking about going to 45's for dirt and gravel.

Bacciagalupe

I've used 23, 24, 25, 28, on aluminum and steel, at different PSI's. And I still don't agree with you. Sorry.

• These designations are not standardized. A 23 from one manufacturer can be wider than a 24 from another.
• You're talking about extremely small differences.
• No one posting here is doing blind tests.

So yeah, I'm extremely skeptical of clams that some eentsy difference that is almost certainly too small to perceive really make a massive difference.

johnny99

If you reduce your tire pressure by 15psi, can you feel the difference? That is approximately the difference you will feel if you switch from 25mm to 23mm tires of the same model. 25mm tires are generally designed to be run at 15psi lower air pressure than 23mm tires of the same model. If you are not reducing your tire pressure when you switch to a wider size, then you screwed up.

Here is Michelin's tire pressure chart. Other brands are similar. https://www.michelinbicycletire.com/m...rpressure.view

hhnngg1

I think the factor you theoretical guys are ignoring is that you'll feel a definite difference the moment you ride over rough patches of road.

I'll agree - on a smooth road, I can't tell the difference at all between 23c and 25. But the moment you ride over any bump, I immediately notice the greatly improved shock absorption, particularly on the front.

I'm pretty sure that's the difference between the obvious differences I'm attesting to versus your theoretical 'can't notice the difference' effects. On a flat smooth road, I'll give you that you can't tell the difference, but at least on the roads I ride, there are enough rough patches that you'll figure out really quick that you're on 25s. Like immediately.

Again, I learned this from experience even before I knew the effect of 25s - in fact, I fully expected there to be zero difference. How wrong I was. (And I inflate at 100psi before every ride.)

znomit

Finally a definite answer to the question "Am I too fat for this sport?"
It would seem 82kg is the maximum acceptable weight.

ColinL

Completely agree. My morning wake-up ride through the neighborhood is about 1/4 cobblestone. (American style with bricks, not Belgian.) I can tell the difference immediately between 23 and 25mm tires, soft-riding vs harsh riding tires in the same size, and 10 psi of air in the same tire.

If I go to extremes-- 23mm slick at 115F/125R compared to 25mm GP4S at 90F/100R-- the difference is so dramatic there is no way anyone would fail to notice it. It feels like an entirely different bike.

hhnngg1

Glad someone agrees with me. Sometimes I think the theoretical stuff about Sheldon this and website that gets a little out of hand with folks that actually haven't even tried the stuff in question.

Darth_Firebolt

the larger tire in the front at lower PSI also increases cornering grip, which is nice on a road bike considering the weight split between the two axles. extra nice if you ride switchbacks in the rain.

FPSDavid

So, if one were to currently ride 23mm GP4000S's @ 100psi front / 110psi back, and I were to get 25mm GP4000S's, what pressures should I be running? 6ft 130lbs

Sorry to bump such an old thread!

bikerjp

So do you think 25mm tires on the C2s would ride like 27s? I'm looking to have some C2s or A23s built and plan to run 25mm tires but maybe that defeats the purpose of the 23mm rims. Or maybe it doesn't mater - wider is wider.

bikerjp

Michelin may be a tire manufacture and therefore have some credibility, but inflating to max PSI if you are over 180lbs is BS. I'm 195-200lbs and NEVER run max PSI. In fact, I'm well below. I think the highest I've ever run is 105 and usually I'm 90/100 or 85/95. I've even experimented down in the 70s (once by accident ). I ride nice roads, cracked and pothole roads and chip seal roads - usually all on the same ride. No pinch flats yet. I use gp4000s on one bike and still on the stock Durano 25s on the new bike.