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Realistically, how ...
 

Realistically, how much difference will 5mm of tyre width make?

 PJay
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[#13535691]

I have a gravel bike and I find the front end a bit jarring on the ridiculously broken up & potholed roads I ride it on. It has a carbon fork, but with its wide, triangular blades it's clearly built for stiffness rather than compliance.

Tyres are 700x40 Maxxis Receptors (120tpi & nice & supple) running at 30psi. 40mm is the max for the frame, but the fork will take a 45mm.

I am a bit of a serial tyre swapper but tyres seem suddenly to be very expensive (I like the look of the new Continental Terra Competitions but they're around £120 a pair!).

The Receptors don't come any larger but there are plenty that do (Gravelking SS look interesting) but would the extra 5mm gain me anything much or should I just wait until they're worn out and have to be replaced?


 
Posted : 26/05/2026 11:12 am
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Yes they would make a difference. Whether it's enough to justify binning your current tyres YMMV.


 
Posted : 26/05/2026 11:16 am
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My hands were a bit sore when I first started riding gravel.  I found that some gel inserts under the bar tape, gloves/mitts with a bit of padding and riding in the drops all helped.

A lot of mitts have good padding but gloves hardly seem to.  But I found a cheap pair of Boardman gloves in Halfords and they are excellent.


 
Posted : 26/05/2026 11:34 am
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I'm not in your position but surely one of those suspension stems would make the biggest difference?


 
Posted : 26/05/2026 11:39 am
convert reacted
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how much difference will 5mm of tyre width make?

A lot. I use 2.6" tyres on my MTB and find them so much better than 2.4"

Coming back to gravel, I bought my gravel bike specifically because it had 5mm greater clearance than the year before model. Whether it was worth the extra £500 and enduring shit gears is up for debate 🙂


 
Posted : 26/05/2026 11:45 am
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Posted by: PJay

would the extra 5mm gain me anything much or should I just wait until they're worn out and have to be replaced?

I wore out my 40mm tyres and replaced them with 45mm. The difference is noticeable but not so much I'd bin some good tyres for it.

How are you measuring the tyre pressure? I've found track pump pressure gagues to be less reliable at lower pressures so there's a chance you could be putting more than 30psi in there. I'd probably experiment with dropping a couple of toots out the valve to see if that helps.


 
Posted : 26/05/2026 11:50 am
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The cross section volume of a tyre has fairly close to a square relationship of the width - volume approximates to Pi * Width^2 / 4 - so a 45mm tyre has approx 25% more volume than a 40mm (which allows a lower pressure to be run for more comfort) 


 
Posted : 26/05/2026 12:02 pm
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Posted by: PJay

but would the extra 5mm gain me anything much

Yes, I'd say so. I recently went from 40 WTB Nano's to 45 Maxxis Ravagers. Difference was very noticeable, although think the carcass of the Ravagers feels a bit thicker and better damped as well.


 
Posted : 26/05/2026 12:07 pm
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It’s not just 5mm width, it’s a considerable increase in height and (therefore) volume. 
I’ve usually got 45s on my gravel bike, but have just chucked a faster rolling 40 on for the summer months. The difference between the sizes is more than you might think


 
Posted : 26/05/2026 12:20 pm
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The problem here is that you're looking at a nominal width.

You need to measure the tyre on your (or an equivalent) rim width. A tyre measuring 44mm might have a 10% smaller volume than a 46mm tyre

Tyre construction will also play a part in the amount of compliance.


 
Posted : 26/05/2026 12:32 pm
 aggs
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You could go up 5mm on the front and keep the rear the same and then when rear is worn you can swap it over to the fresher tyre.

I am just about to do this myself. I have the tyre just not fitted it yet , I may wait for the event I have entered ,and then fit it beforehand as the length of ride will be significantly longer than my regular rides.

So maybe some marginal gains on comfort for me.

I tend to ride the downhills a bit faster on events.


 
Posted : 26/05/2026 2:18 pm
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Yes it makes a difference. 

I found that gel and thick bar tape is as important.

I also think I can feel some firmer sidewalled tyres.


 
Posted : 26/05/2026 3:00 pm
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You also mention forks: I've had a pair of carbon forks that were borderline comfortable. My current steel Genesis forks are anything but...


 
Posted : 26/05/2026 3:05 pm
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I bought the 45mm version to put on the rear, but you could get the 40mm version for the same price from Winstanley, mine took ~10 days to deliver.

https://winstanleysbikes.co.uk/hutchinson-caracal-race-700c-tubeless-tyre

The 45mm is super comfy at ~42PSI with latex tube and the 40mm has even lower rolling resistance.


 
Posted : 26/05/2026 7:57 pm
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I discovered that, on my kona smoke 29er, it was difficult to find a sweet spot on the Conti travel contact 700x47 tyres, between rock hard and clanging the rims on potholes.

moving up to 2.0 made a colossal improvement.

but if you’re maxed out with 45c at the front, would a switch to 27.5 at the rear widen (😩) your options?


 
Posted : 26/05/2026 8:27 pm
 P20
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It should make a lot of difference. I went from 44 to 47mm and you could feel it


 
Posted : 26/05/2026 9:56 pm
 PJay
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Perhaps I need to have another look at tyres.

The Panaracer SS look decent, I don't need anything too chunky. Any experiences?


 
Posted : 26/05/2026 10:02 pm
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The other thing to consider is are they actually any bigger?

Different tyre manufacturers size differently, and sometimes the same manufacturer across a range (for instance my 2.35" Maxxis Ikons, while clearly larger than my 2.1" Ikons, seem a _lot_ smaller than my 2.4" Minions) I've no experience of those.mentioned in the OP but I've had problems with a 2.3" Panaracer actually being larger than a 2.35" Maxxis! 

So is a 45mm Conti actually any bigger than a 40mm Maxxis? Don't just go by the printed numbers, for small differences measure them


 
Posted : 27/05/2026 12:36 am
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Haha, in true STW style not answering your question, but if you are able to slide your saddle back on its rails 5 or 10mm you should find that your hands/arms/shoulders take less of a beating by being slightly unweighted. It's a bit counter intuitive, but has worked for me. Only useful if it doesn't end up knackering your knees by being too far back etc.


 
Posted : 27/05/2026 9:18 am
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No mention that I can see about if you are running tubeless or not and what pressure you are running. Are you running same/similar front and rear. 

Even on road you can run your front tyre a lot soft than you might expect, especially if run tubeless. A lot of folk, especially if they have a road background run old skool road tyre pressures backed off a bit (because they know the tyres are bigger) when in reality they can be backed off a lot. 

I'd be experimenting with tyre pressures (and going tubeless if not already) before resorting to new tyres. 


 
Posted : 27/05/2026 10:53 am
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Do it and you’ve got a spare rear tyre.

Double win.


 
Posted : 27/05/2026 7:21 pm
 PJay
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Sorry I forgot to mention that they are being run tubeless. 30pso both ends but I'll experiment.


 
Posted : 27/05/2026 8:00 pm