MTB-tires as All-round tires for Gravel?

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FlatlandClimber
Posts: 2491
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

This probably has been discussed before, but I didn't find it.
I currently riding quite a lot of gravel on my Open Wi.De. Since there is no Gravel Racing near me, all I do is smash hard through my local forests, trails, and gravel roads. I like being able to ride "everywhere", but I am mainly concered with speed.
I am currently running the Pirelli Cinturato Gravel H (700x45), and I am pretty impressed. They hold speed super well and with the massive width, the traction is impressive, too.
However, over the weekend, it started raining pretty hard and when the trails got muddier, my confidence decreased. I had a few proper slips, including landing flat on my face (which has more to do with me being a sh!t rider), and even had to walk up one trail (legs were fine, grip wasn't).
This had me thinking to switch to Pirelli Cinturato Gravel M(ixed Terrain) (700x45), that are quite a bit knobbier. I tried to find rolling resistance data on these, but couldn't find any. Probably fast for what they are, but slower than the H(ard Terrain) Version.
During my research, I also found BRR's review of the Continental Race King Protection MTB Tire (https://www.bicyclerollingresistance.co ... ction-2020). They have taller knobs than my current tires (probably rather comparable to the Mixed Terrain version of the Pirelli), are obviously wider (27.5x55), but apparently test FASTER than the Cinturato (23.3W vs 20.2W). Also, the puncture protection is still rated very highly.
So my question goes: "Would switching to a smaller wheel (I have a 27.5" pair already) and MTB tires really make me faster/ or even keep me as fast?" Is this really possible? They are very likely grippier and the aerodynamics of all those tires is probably very awful.
What is your experience here? Would love to get some insight from people with experience on the MTB v Gravel conundrum.
Thanks in advance! :beerchug:
Cervelo P5 Disc (2021) 9.1kg
Factor Ostro Gravel (2023) 8.0kg
S-Works SL8 (2023) 6.3kg

*weights are race ready, size 58/L.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT, Crux, Aethos, SL7

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jemima
Posts: 270
Joined: Fri Apr 22, 2011 12:36 am
Location: Perth

by jemima

My rides are kind of the same. Mainly have a 2.1" RocketRon on the back for clearance, with a (dry riding) RaceKing Protection 2.2 on the front. The RocketRon rear does ok on pavement; better once it wears a little.

From what I understand though, the RaceKing can start getting sketchy the wetter it gets. Seems to me your ideal setup (including wet) would be the knobby 27.5x2.2 ReneHerse when it is available to purchase. Those (extralight and standard) should be as fast as a F+R RaceKing Protection setup. Their 3mm knob height and design will be ideal for wet climbing/rides also.

Kind of thinking though, on a fast-rolling wide 700c you'd be rolling a bit quicker than 27.5.
At least that is my experience running the light and sketchy 46mm wide '29er' Furious Fred in dry conditions.
Curve Grovel ti.

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bobrayner
Posts: 122
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by bobrayner

I have mixed-and-matched in the past. It works, but it's not a panacea.

Be careful with clearance when mixing. During the Great Parts Shortage of winter 2020, I bought a rear MTB wheel for my CX bike (because nobody had my preferred wheels in stock), put a standard CX tyre on it... and there's almost zero clearance, because the wider rim gave the tyre room to spread out, with rubber sprues brushing the chainstay.

It seems likely that you would get lots of extra grip. However, there's no such thing as a free lunch - would switching to a different tyre genre really give you lots of extra grip without any increase of rolling resistance? Is there zero difference in the testing regime?
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FlatlandClimber
Posts: 2491
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

My bike is rated for 2.4" MTB wheel, and I have cleared 2.35 Schwalbe no problem. 2.2 should work well. I just fail to imagine them to be nearly as quick as the 45c Pirellis ...
Cervelo P5 Disc (2021) 9.1kg
Factor Ostro Gravel (2023) 8.0kg
S-Works SL8 (2023) 6.3kg

*weights are race ready, size 58/L.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT, Crux, Aethos, SL7

TheRich
Posts: 1037
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

FlatlandClimber wrote:
Mon May 03, 2021 9:15 am
This probably has been discussed before, but I didn't find it.
I currently riding quite a lot of gravel on my Open Wi.De. Since there is no Gravel Racing near me, all I do is smash hard through my local forests, trails, and gravel roads. I like being able to ride "everywhere", but I am mainly concered with speed.
I am currently running the Pirelli Cinturato Gravel H (700x45), and I am pretty impressed. They hold speed super well and with the massive width, the traction is impressive, too.
However, over the weekend, it started raining pretty hard and when the trails got muddier, my confidence decreased. I had a few proper slips, including landing flat on my face (which has more to do with me being a sh!t rider), and even had to walk up one trail (legs were fine, grip wasn't).
This had me thinking to switch to Pirelli Cinturato Gravel M(ixed Terrain) (700x45), that are quite a bit knobbier. I tried to find rolling resistance data on these, but couldn't find any. Probably fast for what they are, but slower than the H(ard Terrain) Version.
During my research, I also found BRR's review of the Continental Race King Protection MTB Tire (https://www.bicyclerollingresistance.co ... ction-2020). They have taller knobs than my current tires (probably rather comparable to the Mixed Terrain version of the Pirelli), are obviously wider (27.5x55), but apparently test FASTER than the Cinturato (23.3W vs 20.2W). Also, the puncture protection is still rated very highly.
So my question goes: "Would switching to a smaller wheel (I have a 27.5" pair already) and MTB tires really make me faster/ or even keep me as fast?" Is this really possible? They are very likely grippier and the aerodynamics of all those tires is probably very awful.
What is your experience here? Would love to get some insight from people with experience on the MTB v Gravel conundrum.
Thanks in advance! :beerchug:
I'd imagine for actual gravel riding, the sweet spot is somwhere in the 40-45mm area. With 27.5 and MTB tires you're giving up a little rollover, adding weight, and adding drag by adding traction you don't need....for actual gravel riding.

Which isn't to say that there isn't a place for 27.5 and MTB sized tires, it's just not in a traditional gravel ride and especially not a gravel race.

FlatlandClimber
Posts: 2491
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

I'd say I am literally riding "cross country"! Not XC, but across everything coming my way. Mostly forest paths, roads, and gravel, but also mud, trails and cobbles, whenever they cross my Way.
I have a great 45mm tire, but it has weaknesses in grip.
Cervelo P5 Disc (2021) 9.1kg
Factor Ostro Gravel (2023) 8.0kg
S-Works SL8 (2023) 6.3kg

*weights are race ready, size 58/L.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT, Crux, Aethos, SL7

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pdlpsher1
Posts: 4016
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

What I do is adjust the air pressure depending on the terrain I'm expecting. If I think grip will be an issue I run lower pressures. It's like having a different set of tires when I run at lower pressures. When I do a climbing ride where it's one big climb up and one big descend down, I drop the pressure at the top of the climb. To me this is the easiest solution other than going with two wheelsets. Lower pressure = larger contact patch. But of course if you have bike tinkering OCD then get a second set of wheels. Most of us here on WW has bike tinker OCD 🤣

By the way I'm running 650B 40mm wide gravel tires. Just because you have 650B it doesn't mean you have to go super wide. I love my 650B setup. The bike feels so much more nimbler (reduced the trail and also vastly reduced rotational inertia) and playful. It's like riding a go-cart if there's one word to describe it. It's a lot of fun doing technical bits on the 650B due to the reduced trail and nimbleness. I won't ever go back to 700C on my gravel bike.

TheRich
Posts: 1037
Joined: Tue Jan 01, 2019 1:36 am

by TheRich

FlatlandClimber wrote:
Wed May 05, 2021 10:25 pm
I'd say I am literally riding "cross country"! Not XC, but across everything coming my way. Mostly forest paths, roads, and gravel, but also mud, trails and cobbles, whenever they cross my Way.
I have a great 45mm tire, but it has weaknesses in grip.
I can go mountain biking (and ride relatively quickly compared to mountain bikes) on my CX bike with agressive 38mm tires and grip isn't an issue because generally I can't go fast enough due to the small (volume) tires and lack of suspension to max out the grip from the tires. Until you get up into MTB sizes, small volume will be an issue, but not as much as the lack of suspension.

It does require a lot more focus on technique though...and if your technique is off, you're going to have a hard time of it.

CampagYOLO
Posts: 705
Joined: Thu May 06, 2021 3:58 pm

by CampagYOLO

I just don't think there's such thing as a magic tyre that rolls really well but still offers good grip in wet, loose conditions.
It's why CX racers have so many different tyres available to them to use the best one for the given conditions.

Either prioritise what you're looking for in a tyre and use that or run a couple of sets of wheels, one with the Pirelli's and one with something slower but grippier and keep a close eye on the weather forecast!

The closest I've found to an all round tyre is either the Maxxis Rambler or the Teraveil Rutland but both of them will probably not be fast as your current Pirellis.
Last edited by CampagYOLO on Fri May 07, 2021 12:58 pm, edited 1 time in total.

Tifosiphil
Posts: 359
Joined: Wed Nov 14, 2018 11:09 pm

by Tifosiphil

I'd be interested if anyone has any recommendations for mud gravel tyres, I've got clearance for 45mm 700c or 50mm 650b.

Been quite tempted by the Conti Mud King in a 45mm 650b version

CampagYOLO
Posts: 705
Joined: Thu May 06, 2021 3:58 pm

by CampagYOLO

Tifosiphil wrote:
Fri May 07, 2021 9:54 am
I'd be interested if anyone has any recommendations for mud gravel tyres, I've got clearance for 45mm 700c or 50mm 650b.

Been quite tempted by the Conti Mud King in a 45mm 650b version
I've used Panaracer Gravelking AC's in muddy CX races and they're really good, lots of grip and supple. I wouldn't go too wide if riding in mud so the tyre bites into the ground. Also means that you have plenty of mud clearence which you will need.

Tifosiphil
Posts: 359
Joined: Wed Nov 14, 2018 11:09 pm

by Tifosiphil

CampagYOLO wrote:
Fri May 07, 2021 10:39 am
Tifosiphil wrote:
Fri May 07, 2021 9:54 am
I'd be interested if anyone has any recommendations for mud gravel tyres, I've got clearance for 45mm 700c or 50mm 650b.

Been quite tempted by the Conti Mud King in a 45mm 650b version

I've used Panaracer Gravelking AC's in muddy CX races and they're really good, lots of grip and supple. I wouldn't go too wide if riding in mud so the tyre bites into the ground. Also means that you have plenty of mud clearence which you will need.
Perfect, thank you. I tried using the Gravelking SK's last winter and they were useless in anything slightly wet or slippy (great for everything else though).

I may give these a go if I decide against the RH Steilacoom. Just can't bring myself to spend £160 on tyres at the moment

FlatlandClimber
Posts: 2491
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

With a sample size of n=1, I am rather impressed with the Conti RaceKings.
The do feel slower than the Pirelli Cinturato Gravel, which is little surprising. Also, I had a few really harsh head wind sections, where I really heard the aero drag that a spinning, fat, knobby tire creates. Probably not a huge penatlty compared to a knobby Gravel tire, but one thing to consider also.
Grip and comfort was really good, could have even ridden lower pressure (30Psi). I rode up muddy 20% wet single trails and down the other side and it all went well.
I will really put it to the test this upcoming weekend, and see how I feel about off-road capability then.
On Road capability is the best of any 27.5 I have experienced, but not quite as good as the Pirelli.

Image
Image
Cervelo P5 Disc (2021) 9.1kg
Factor Ostro Gravel (2023) 8.0kg
S-Works SL8 (2023) 6.3kg

*weights are race ready, size 58/L.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT, Crux, Aethos, SL7

spartacus
Posts: 1049
Joined: Mon Apr 04, 2011 6:53 pm

by spartacus

I've been experimenting with this by using 2.1" Thunder Burts and 2.2" Race Kings (650b) on my hakka. The MTB tires are definitely solid off road and they roll OK on pavement. They are however definitely slower than a road tire on pavement. I'm going to try ultradynamico cava race tires and see if they feel faster on the road. My SO has rene herse 700x48 tires and they seem comparable rolling resistance wise to the MTB tires. It looks like people winning gravel races are on really narrow tires though. On the other hand segment times on hardtails are often quite fast so IDK what to think. My guess is the MTB tires do have good rolling resistance on the road but not at the pressures you'd want to run them at off road. Maybe narrower tires still have good RR on the road at the pressures you'd use them off road.

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fourfa
Posts: 107
Joined: Mon Sep 26, 2011 3:04 am

by fourfa

FWIW I run my low-knob gravel tires at 40psi for the pavement (max for the rim otherwise I'd run higher) and drop to 25psi (as needed... I'm a bigger guy) for trail, then back up when back on pavement. Round here I just spit out pea gravel on the trail at high pressure and can't grind up the steep bits, and I definitely feel the drag on pavement at low pressure.

I assumed everyone is changing pressure on rides? Maybe if you're not 200+lbs there's a compromise value that works well enough in both regimes, I wouldn't know firsthand

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