gravel bike - tyre pressures

[designndrive62]

I have a GT grade gravel bike, with WTB tyres.

The tyre walls state minimum tyre pressure of 35psi, but whenever I am on any sort of uneven road, let along bridleway or off road section, the ride is incredibly harsh, on rougher off road sections it feels almost unrideable.

Any advice on how people are setting up their bikes? I have seen all sorts from doubling up bar tape to flexi headsets. Or should i just ignore the manufacturer stamp and run lower pressures?

[Wardy78]

Depends on the tyre size etc.

I run WTB Horizon 47mm and WTB Resolute TCS 50mm on identical Mavic rims on my gravel bike. Both tubeless, obviously.

I run the 47s on road and hard surfaces so run at about 35-40, that's very compliant and a cushioning soft ride. The 50s, are more off road so they're run even lower, around 30.

[JEA1K]

designndrive62 said:

I have a GT grade gravel bike, with WTB tyres.

The tyre walls state minimum tyre pressure of 35psi, but whenever I am on any sort of uneven road, let along bridleway or off road section, the ride is incredibly harsh, on rougher off road sections it feels almost unrideable.

Any advice on how people are setting up their bikes? I have seen all sorts from doubling up bar tape to flexi headsets. Or should i just ignore the manufacturer stamp and run lower pressures?

Yes on your last point (the calculator below is always a useful starting point) ... go with your own judgement on comfort to suit the surfaces you ride on. There are a few variables .. tyre width, your weight, bike weight etc ... maybe start with 30psi and then work your way down to 25psi and see what feels best.

https://axs.sram.com/guides/tire/pressure

[jamm13dodger]

Might be a silly question but its not something as simple as you needing to relax a bit? If you have a death grip on the bars try to loosen your grip a bit, if you are sitting in the saddle try standing with bent legs as needed and using your legs as suspension if that makes sense.

Apologies if I'm "preaching to the converted" but if you are from a pure road background I thought it was worth mentioning.

[MajorMantra]

JEA1K said:

Yes on your last point (the calculator below is always a useful starting point) ... go with your own judgement on comfort to suit the surfaces you ride on. There are a few variables .. tyre width, your weight, bike weight etc ... maybe start with 30psi and then work your way down to 25psi and see what feels best.

https://axs.sram.com/guides/tire/pressure

+1 this calculator is excellent. And yes ignore the 'minimum' pressure on the tyre.

[frisbee]

jamm13dodger said:

Might be a silly question but its not something as simple as you needing to relax a bit? If you have a death grip on the bars try to loosen your grip a bit, if you are sitting in the saddle try standing with bent legs as needed and using your legs as suspension if that makes sense.

Apologies if I'm "preaching to the converted" but if you are from a pure road background I thought it was worth mentioning.

I'm from a pure road background, I've actually got a GT Grade as well, which I've mostly ridden on the road.

I've got another set of wheels with gravel tyres on, off road the ride is surprisingly good, I was expecting to hammer my forearms like an old school 26" mountain bike with no suspension but I was dropping tyre pressures more for traction than anything else.

[numtumfutunch]

Use a calculator

For gravel I use 30psi tubeless however my rims, tyres and body weight are probably not the same as you

Cheers

[oddman]

jamm13dodger said:

Might be a silly question but its not something as simple as you needing to relax a bit? If you have a death grip on the bars try to loosen your grip a bit, if you are sitting in the saddle try standing with bent legs as needed and using your legs as suspension if that makes sense.

Apologies if I'm "preaching to the converted" but if you are from a pure road background I thought it was worth mentioning.

I was thinking the same. If OP comes from road background may be expecting a little too much when surface gets uneven.

I think riding a gravel bike does demand similar technique to an old school rigid mountain bike or CX. It's hard to describe but slightly highly gear, lower cadence, relaxed grip and sort of 'floating' rather than sitting and spinning. Annoyingly for me, this puts me significantly outside my zone 2 of comfort and tipping towards threshold riding.

That being said, my Specialized Crux came with 38mm road biased tyres similar to the 40mm tyres on the OP's and I rapidly got pressures down to 30psi to make it more comfortable. I think some tyres are plain nasty and ride like run flat car tyres so a change of tyre could be in order especially if OP is taking on more challenging terrain.

Long descents can be pretty fatiguing and jarring whatever you do. I can see why some fit dropper posts.

[OutInTheShed]

designndrive62 said:

I have a GT grade gravel bike, with WTB tyres.

The tyre walls state minimum tyre pressure of 35psi, but whenever I am on any sort of uneven road, let along bridleway or off road section, the ride is incredibly harsh, on rougher off road sections it feels almost unrideable.

Any advice on how people are setting up their bikes? I have seen all sorts from doubling up bar tape to flexi headsets. Or should i just ignore the manufacturer stamp and run lower pressures?

A tyre can only deflect so far.

One day, someone will invent bikes with suspension....

[HenryV1415]

Lower your pressure a bit at a time. Eventually they will feel horrible in the corners and you will get some rim impact on rocks. Then they are too low. It’s really trial and error depending upon your weight, your trail type, and how you like to ride.

[OutInTheShed]

HenryV1415 said:

Lower your pressure a bit at a time. Eventually they will feel horrible in the corners and you will get some rim impact on rocks. Then they are too low. It’s really trial and error depending upon your weight, your trail type, and how you like to ride.

You'll know when they are too low, as a slightly bigger/sharper bump than you were optimising for will wreck the tyre or the rim, maybe throwing you off the bike.

It might be better to follow the tyre maker's advice on pressures, and ride the bike in a manner that's appropriate for a bike with no suspension.
This is why full sus bikes are great for those of us who aren't fit enough or committed enough to be out of the saddle the whole time.

Obviously, if you are an 8 stone female, you can use a lower pressure than a 15 stone UFB.

One of my bikes is an old CX bike I use for 'gravel', with that I am well aware I need to either improve my fitness and style, keep to smoother tracks, slow down and be a bit careful, or choose my full sus bike instead. It's a great bike for what it's good at. But being comfy on rough ground wasn't in the design brief. Fatter tyres will move the goalposts, but only so far!

[designndrive62]

Thanks for the advice everyone, I have come from the mountain bike side, and got the gravel bike for commuting to work and for doing the occasional longer adventure linking up some bridleways with longer road sections that are a drag with the gearing on the MTB.

Sounds like I have a mix of all three of not quite right with the pressures, expecting a little too much from the ride anyway, and not quite riding in the right style / position.

I'll start with the pressure calculator and go from there

[Chicken Chaser]

I was out yesterday on gravel with 35mm tyres (bike will take a maximum of 37/38). It's an 8 year old gravel bike so it's probably more road+ than full on gravel these days. That said I was running pressures at 45psi and checking against that link above, it was almost spot on for the optimal, which was 48/49. It does feel a bit bouncy but if you go too low, you risk pinch flats and rim impacts if you've got tyres with soft sidewalls.