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32mm gp5000tl measure smaller, still get benefits?

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32mm gp5000tl measure smaller, still get benefits?

Old 10-20-20, 08:20 AM
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degoydegoy
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32mm gp5000 tl measure smaller, still get benefits?

I've got around 2k miles on my 30mm WTB exposure tubed tires on my road bike. They have been good, minimal flats, but on the rough roads around here I sometimes feel like I'm going to crash from hitting a bump or pothole.

Recently got a gravel bike with 47mm 650b that rolls, a bit slower and with a bit more effort, over everything easily. That got me thinking that a bigger, tubeless tire might allow me to go faster with more confidence on the road bike.

Got a pair of gp5000 tl 32mm (max approved size for my 2018 synapse), mounted the front tubeless with no problems except that it measures around the same size, even smaller at lower pressures than the 30mm Exposure.

So here's the question: did I waste time and money on these new tires which are supposed to be wider but are actually smaller? Even though they measure smaller, do I still somehow get the increased ability to roll more smoothly over rough roads? Maybe as the tire depresses under my weight and that of the bike it will widen up more than the 30mm they are replacing?

Thanks in advance for any insight here

Last edited by degoydegoy; 10-20-20 at 08:22 AM. Reason: Tire name fix
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Old 10-20-20, 08:34 AM
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The GP5k, along with several other tires like the P Zero race TLR and Schwalbe Pro One addix, is part of a new crop of tires that adhere to the new ETRTO standard. 32mm tires are measured on 21mm internal-width rims now, rather than the prior 17mm I believe. This means that the tires are at least 2mm smaller than before.

Unfortunately, if your goal was to get a bigger tire to absorb bigger hits... yeah you probably wasted your money. But the GP5k is a relatively supple tire so you should be able to get away with lower pressures and not have that sluggish feeling.

how much do you weigh and what pressure do you run in the 32mm gp5ks?
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Old 10-20-20, 08:54 AM
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Originally Posted by smashndash View Post
The GP5k, along with several other tires like the P Zero race TLR and Schwalbe Pro One addix, is part of a new crop of tires that adhere to the new ETRTO standard. 32mm tires are measured on 21mm internal-width rims now, rather than the prior 17mm I believe. This means that the tires are at least 2mm smaller than before.

Unfortunately, if your goal was to get a bigger tire to absorb bigger hits... yeah you probably wasted your money. But the GP5k is a relatively supple tire so you should be able to get away with lower pressures and not have that sluggish feeling.

how much do you weigh and what pressure do you run in the 32mm gp5ks?
My GP5000 TL's measure 34mm on 25mm internal-width-rims at 65 psi. They did "grow" a little after a few rides. As mentioned earlier the newer tires seem to measure close to size. The GP4000's seem to be at least 2mm larger. Older bike that I have would not fit GP4000's in 28 mm but easily fits them with the GP5000's.
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Old 10-20-20, 08:56 AM
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Originally Posted by smashndash View Post

how much do you weigh and what pressure do you run in the 32mm gp5ks?
Thanks for the info.

Also forgot to mention that I'm on a 19mm internal rim if that matters. I weigh 140 and tried the gp5000 at about 45-50 psi.

It looks like I have tons of extra space in the front but the back seems to be true to Cannondales spec of 32mm max. Wondering if I should put something >32mm on the front, move the gp5000 32mm to the back, and return the unused gp5000 32mm which was intended for the back? Are there any slick tires that big? I don't need any tread since this bike will be used exclusively on the road
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Old 10-20-20, 09:00 AM
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Originally Posted by Sasquatch16 View Post
My GP5000 TL's measure 34mm on 25mm internal-width-rims at 65 psi. They did "grow" a little after a few rides. As mentioned earlier the newer tires seem to measure close to size. The GP4000's seem to be at least 2mm larger. Older bike that I have would not fit GP4000's in 28 mm but easily fits them with the GP5000's.
Yeah it's probably my 19mm internal stock rim width. If my goal is to have a fast *and* more bump absorbant tire, maybe I have to get larger rims? Seems like tires any bigger than 32mm have tread on them
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Old 10-20-20, 09:28 AM
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As for getting a wider tire up front---most of your weight in on the rear tire, so your best bet would be to find a rear tire which just fit and save the GP5Ks for the front.
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Old 10-20-20, 09:29 AM
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I have a set of the 32mm GP5000s on my 25mm internal width road wheelset with latex tubes and it is exceptionally smooth and they feel super fast. My wife has a set of the 32mm GP5000 TLs mounted on 19mm internal wheels. Her bike is also super smooth. I don't know that you can get a better ride...

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Old 10-20-20, 10:11 AM
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Originally Posted by degoydegoy View Post
Thanks for the info.

Also forgot to mention that I'm on a 19mm internal rim if that matters. I weigh 140 and tried the gp5000 at about 45-50 psi.

It looks like I have tons of extra space in the front but the back seems to be true to Cannondales spec of 32mm max. Wondering if I should put something >32mm on the front, move the gp5000 32mm to the back, and return the unused gp5000 32mm which was intended for the back? Are there any slick tires that big? I don't need any tread since this bike will be used exclusively on the road
32mm tires for a 140lb rider is quite a lot for the road. I'm not sure you need a bigger tire unless your roads are reeeeaally bad. 45-50 psi is not as low as you can go. I weigh about the same and run 55-60psi in 25mm tires.

With wide rims and TL, 40psi should be feasible but perhaps not much lower. At that point I would wonder if a road bike is the right fit.

Do not fall into the trap of wide rims. Wider rims only help if you're running super low pressure and you're experiencing tire flop. Are you?

You're free to try a bigger front tire like a 35mm Cinturato, Gravelking, or Rene Herse. It will probably slow down your handling a bit. But the only reason to get a bigger tire up front is if you're running into pinch flats/rim damage due to low pressures on a smaller tire. If not, just keep lowering the pressure on your current tires.

Last edited by smashndash; 10-20-20 at 02:34 PM.
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Old 10-20-20, 11:40 AM
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The 5000 series, as noted above, will grow a bit when left inflated to sidewall pressure. But no, bigger softer tires won't inspire confidence particularly. I still ride 23mm Conti 5000 on 19mm inside rims, inflated to 80 front, 100 back for my 148 lbs. They feel great on technical paved descents. Deep alu rims, aero spokes, it's a fast setup for the cost and plenty comfortable enough for my carbon bike.
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Old 10-20-20, 12:16 PM
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Originally Posted by Carbonfiberboy View Post
The 5000 series, as noted above, will grow a bit when left inflated to sidewall pressure. But no, bigger softer tires won't inspire confidence particularly. I still ride 23mm Conti 5000 on 19mm inside rims, inflated to 80 front, 100 back for my 148 lbs. They feel great on technical paved descents. Deep alu rims, aero spokes, it's a fast setup for the cost and plenty comfortable enough for my carbon bike.
​​​​
I've only been road biking for about a year now, and just got the gravel bike two weeks ago. My bike handling skills aren't that great and I'm older and my balance is a definitely not what it once was. As a result I've had a few oh sh-- moments where I didn't see the pothole or bump until it was too late and nearly crashed. On the gravel bike with 47mm tires I ride over similar obstacles at similar speeds and it keeps tracking straight ahead. So I was hoping to get a little closer, on my road bike, to the confidence I feel on the gravel bike without loosing too much of the fun and speed of the road bike.

So thanks for that perspective, it seems now like I might be expecting too much from the road bike
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Old 10-20-20, 12:30 PM
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Originally Posted by smashndash View Post
32mm tires for a 140lb rider is quite a lot for the road. I'm not sure you need a bigger tire unless your roads are reeeeaally bad. 45-50 psi is not as low as you can go. I weigh about the same and run 55-60psi in 25mm tires.

With wide rims and TL, 40psi should be feasible but perhaps not much lower. At that point I would wonder if a road bike is the right fit.

Do not fall into the trap of wide rims. Wider rims only help if you're running super low pressure and you're experiencing tire flop. Are you?

You're free to try a bigger front tire like a 35mm Cinturato, Gravelking, or Rene Herse up front. It will probably slow down your handling a bit. But the only reason to get a bigger tire up front is if you're running into pinch flats/rim damage due to low pressures on a smaller tire. If not, just keep lowering the pressure on your current tires.
Not so much that the roads are really bad, but there are some really bad spots, and it would be nice to worry less about them. Thanks for all the input, I'm understanding this better now. I think I'll just try lowering the pressure a bit more, try riding the rough spots and see if the bike feels more stable, and try riding the fast parts and see if it still feels fast
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Old 10-20-20, 12:45 PM
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Yeah at the same weight as you, OP, I think a 32mm GP5K at that pressure is about as wide and low as I'd want to go to still enjoy a fast but comfortable ride on the road. You have to be attentive if you want to benefit from having a road bike; for sure it's the wrong style of bike if you want to have it absorb every bump on the road when you make a mistake.
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Old 10-20-20, 02:39 PM
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Originally Posted by degoydegoy View Post
​​​​

So thanks for that perspective, it seems now like I might be expecting too much from the road bike
There's nothing wrong with wanting something different. Keep in mind that road bikes, especially road race bikes (which is presumably what you have) are designed for professionals with expert handling abilities who demand razor-sharp responsiveness and generally ride on great pavement. If that doesn't suit your taste, maybe you can get another wheelset for your gravel bike, or trade your road bike for an all-road bike that can fit 35-40mm slicks.

If you have tons of money lying around you could even look into something like the Domane. It'll fit the fat tires you want plus it has built-in suspension. Might be a bit overkill for road but if your priority is stress-free riding even on the most broken pavement, it could be worth looking into.

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Old 10-20-20, 04:52 PM
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Originally Posted by degoydegoy View Post
​​​​
I've only been road biking for about a year now, and just got the gravel bike two weeks ago. My bike handling skills aren't that great and I'm older and my balance is a definitely not what it once was. As a result I've had a few oh sh-- moments where I didn't see the pothole or bump until it was too late and nearly crashed. ...

Not so much that the roads are really bad, but there are some really bad spots, and it would be nice to worry less about them. Thanks for all the input, I'm understanding this better now. I think I'll just try lowering the pressure a bit more, try riding the rough spots and see if the bike feels more stable, and try riding the fast parts and see if it still feels fast
Part of riding a road bike is giving up that bulldozer mentality. 47 mm tires and slack steering angles, sure, roll over anything ... but when you get a road bike you get a little sharper handling, a little quicker response to acceleration and turning, and a little less capacity to not care what you hit.

Frankly, you should get a little more aware in any case (Purely my opinion,) because slamming over obstacles unwitting can lead to serious injury .... one of those pot holes will pop or pinch-flat your tire or bend your rim, or just knock you far enough out of balance that you end up on the pavement, and I can tell you, the older I get, the more every crash hurts.

Even if your bike Can roll over most stuff ... unless you are riding a full-suspension mountain bike, best to scan the road for obstacles. One time that little hole will turn out to be a big rock or a turtle or a Really deep hole and you will suddenly be given the opportunity to examine the pavement in intimate detail .....

That aside (and both more miles and a little more awareness will make that a habit, it's no big deal,) going with a lot lower pressure invites pinch flats when you hit a bad bump. My second-to-last sort of big crash happened last year when I pinch-flatted my front tire and didn't notice it, until I dove hard into a downhill turn (which I ordinarily don't do, but for reasons too convoluted to bother with here .... ) and the added pressure increased air loss Very quickly, my tire flopped all around, I did my best shimmy-shake dance to keep it upright, and finally went flying.

Five pounds of pressure up front might have prevented that. Usually I top off my tires before each ride, but this time I thought I could get away with the front a little softer than usual. I did get away .... but far from unscathed.

Go for 40 psi if you like .... but if you like to hit big holes and you run soft tires .... well, that equation resolves into road rash, eventually.

Roads where I ride are pretty good, and since I usually ride the same roads I know where most of the issues are ... i get surprised now and then ("Is that a Christmas Tree blocking the lane" (panic braking .... )) but I take great care not to get stuck on the bad pavement by traffic, or to run over the stuff I know might be sketchy. When riding new roads, I slow down as much as I need to to have a buffer, and if the roads are quiet, I keep away from the edge so I have room to move in both directions if I need to.

Also, you can learn to ride a little lighter. With me it is instinct that I rise up a tiny bit on my legs to get my butt of the saddle if I know I am going to hit some bad road .... it is an MTB thing, you let the bike follow the terrain and you manage the bike, instead of trying to push the bike into the trail. So if you have time to see a hole but don't have time to avoid it, lighten up. You can time it so you are actually pushing off the pedals a tiny bit (I am clipped in so it is a millimeter) but your weight isn't pounded down onto the bike at the moment of impact. Better for your body, much better for your bike, and you have a much better chance of keeping it tire-side down.

If you keep riding you will learn this as second nature--you won't even think, as you scan the road ahead. And it isn't foolproof (or I am too big a fool) because every now and then I whack a new, and sometimes huge pot hole ... and I always cringe, wondering what damage I might have done to my wheel. So far, so good .... so yeah, you will survive and do fine if you just keep riding.

Last edited by Maelochs; 10-20-20 at 04:55 PM.
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Old 10-21-20, 10:36 AM
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So I've decided to just go ahead and mount the rear gp5000 tl and ride them. If somehow they don't feel as stable as the old, and slightly larger, WTB exposure 30mm tires, I can always put those back on and I'm out $110.

Many thanks to everyone who replied, I have learned a lot, and the stuff I'm already doing intuitively I'll be focusing on more in upcoming rides. I'm running into posting limits so I can't seem to reply to everyone individually. Thanks for making this forum such a great resource.

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Old 10-21-20, 10:44 AM
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2 mm? Really?

I wonder much difference the "a silly millimeter longer" of Chesterfields made for their users.
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Old 10-21-20, 10:54 AM
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Originally Posted by degoydegoy View Post
So I've decided to just go ahead and mount the rear gp5000 tl and ride them. If somehow they don't feel as stable as the old, and slightly larger, WTB exposure 30mm tires, I can always put those back on and I'm out $110.
I wouldn't be surprised if the Contis are more supple and comfy than the WTB at about the same measured size - I would actually be shocked if they were so noticeably worse that you'd opt to take them off and not use them. IOW, you'll get your money's worth.
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Old 10-21-20, 11:08 AM
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I remember when we had threads on here about how big of a difference it would be to go up to 23mm tires. They were bigger and softer.

At some point none of this actually matters and you have to still just go out and pedal the bike.
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