Front tyre wider than rear - can of worms

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432r
Posts: 52
Joined: Mon Apr 25, 2011 2:09 pm

by 432r

Hello all.,
I don’t want to open a can of worms but I was wondering around the implications on safety/balance/handling of running a front tyre 1-2mm wider on the front (to the rear) to improve handling?
Eg if you had a 23 rear, running a 24/5 front.

I know continental sells staggered force/attack, what I am talking about it the reverse where the front is slightly wider. My rims are 25 so I’m not concerned on aero impact.

Eg In a criterium you lose front grip (typically) before rear when cornering hard, so that was my thought process around it. It’s should be noted due to clearance I cannot run wider than 23 in the rear -

Opinions welcome -


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Last edited by 432r on Tue Nov 02, 2021 6:47 am, edited 1 time in total.

by Weenie


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istigatrice
Posts: 849
Joined: Sat May 12, 2012 8:32 am
Location: Australia

by istigatrice

It'll only be a nuanced effect, and as usual take the bike for a shorter ride first before doing anything serious just to confirm. If you notice anything it'll likely be slightly 'slower' handling (maybe more of a tendancy to track in a straight line).

Some things to consider:
Tyres can differ by 1-2mm even if they're the same brand (especially if one is older than the other)
If you're buying tyres labelled as 25mm they may measure 27mm so you may be looking at 23mm vs 27mm as before that shouldn't affect it much.

With all that said it'll probably look sh!t so I'd recommend looking into grippier tyres first. I can't imagine a good set of 23mm tyres letting go especially in the dry, but maybe your circuits and rider weight is a little different to me.
I write the weightweenies blog, hope you like it :)

Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)

jlok
Posts: 2400
Joined: Tue Jun 30, 2015 3:30 am

by jlok

It's a can of worm being opened and sealed sporadically. I'm not sure if you are aware of the control difference between a wide and narrow tire, plus the lil bit difference of trail figure / HT angle (I guess only a handful people care about this).

Yea, it's cheap to experiment so why not go pick a wider tire and try in a safe manner?
Rikulau V9 DB Custom < BMC TM02 < Litespeed T1sl Disc < Giant Propel Advanced SL Disc 1 < Propel Adv < TCR Adv SL Disc < KTM Revelator Sky < CAAD 12 Disc < Domane S Disc < Alize < CAAD 10

432r
Posts: 52
Joined: Mon Apr 25, 2011 2:09 pm

by 432r

istigatrice wrote:It'll only be a nuanced effect, and as usual take the bike for a shorter ride first before doing anything serious just to confirm. If you notice anything it'll likely be slightly 'slower' handling (maybe more of a tendancy to track in a straight line).

Some things to consider:
Tyres can differ by 1-2mm even if they're the same brand (especially if one is older than the other)
If you're buying tyres labelled as 25mm they may measure 27mm so you may be looking at 23mm vs 27mm as before that shouldn't affect it much.

With all that said it'll probably look sh!t so I'd recommend looking into grippier tyres first. I can't imagine a good set of 23mm tyres letting go especially in the dry, but maybe your circuits and rider weight is a little different to me.
I guess letting go is the wrong terminology, I guess a side effect (people speak of) in going for wider tyres is ‘better handling’.
In reality how much true handling improvement is there going from 23->25 when using 25mm rim width on both?


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istigatrice
Posts: 849
Joined: Sat May 12, 2012 8:32 am
Location: Australia

by istigatrice

I think I get what you mean, the right tyre width would just 'feel' right/better? Without necessarily (objectively) gripping better?

In that case I think it'll be highly subjective, and depend a lot on what you like/how you ride. So with that in mind I'd say just buy a nice 25mm tyre, try it and if you don't like it then you've learnt something (and hopefully one of your other bikes/riding buddies can take that tyre so it doesn't go to waste).

P.S. I think the reason why people run wider at the rear is because the rear is loaded more, and so there's more 'benefit' to be had there from a wider tyre.
I write the weightweenies blog, hope you like it :)

Disclosure: I'm sponsored by Velocite, but I do give my honest opinion about them (I'm endorsed to race their bikes, not say nice things about them)

Hexsense
Posts: 3269
Joined: Wed Dec 30, 2015 12:41 am
Location: USA

by Hexsense

Yes I do it.
On MTB.

My road bike use 25 front 28 rear for aerodynamic and weight balance reason. Rear tire support 60% of total rider weight while front only 40%. That's 50% difference in weight they support, so rear deserve bigger size plus aerodynamic doesn't matter back there. The result is that I can run pretty similar tire pressure front and rear rather than front much lower pressure than rear. This make it feel consistent and easy to "know" them well. Many people I that fall simply run front tire pressure too hard. Using same front and rear tire pressure if you have the same tire width is a bad practice which kill front tire grip. :evil:
On road, tires are narrow so bigger tire is thought to roll better too so bigger tire in the back where it support 60% of rider weight make it roll better.


On MTB, it's 2.4" front and 2.25" rear for grip reason as you said. Not only that, front tire also has more aggressive knobs than rear.
Why?
Because I absolutely can't afford to lose grip on front tire. But it's fine to skid the rear tire a bit before side knob bite back. I don't have such biting side knobs on road bike so (uncontrolled) rear skid (at a higher speed than MTB) can also be serious and harder to recover on road bike.
On MTB, tire width are way pass the point of optimal width for rolling efficiency. So 2.25" tire roll better than 2.4"** and since 70% of rider weight is on rear wheel on MTB in seat position (it change a lot as I stand up though), lets put a better rolling tire on there. Front tire is slower but it only carry 30% of my weight so the combined effect is not gravely significant. This, however, result in big tire pressure differential between front and rear tire though. Like 16psi front 21psi rear.

** Remark: many say 2.4" absorb bumps better so it still roll better than 2.25" tire. That maybe true for hardtail on gnarly stuff. However, my MTB have rear suspension in place so 2.25 is faster.

432r
Posts: 52
Joined: Mon Apr 25, 2011 2:09 pm

by 432r

Thanks all for your thoughts :)


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nafaiutb
Posts: 77
Joined: Mon Jan 18, 2016 9:51 pm

by nafaiutb

Hexsense wrote:
Tue Nov 02, 2021 4:45 pm

Rear tire support 60% of total rider weight while front only 40%.
Except when you're braking, and there's even more weight on the front when you're going fast downhill & braking 🤔.
Or maybe it's flat where you ride...
I'm like you for MTB though - big knobbly tyre on the front 👍

Hexsense
Posts: 3269
Joined: Wed Dec 30, 2015 12:41 am
Location: USA

by Hexsense

right but
1) braking is like less than half percent of the ride time.
2) it's not when I concern about balancing rolling resistance and comfort.
3) pressure set for 40% of the weight can handle 100% of the weight without pinch flat, if you don't hit something hard at the same time.

Still, point taken. That's the reason my MTB front use 75% tire pressure of the rear pressure despite 30:70 weight balance and 2.4 vs 2.25 tire size. If it's all flat, it might be 13psi front vs 21psi rear. But with elevation, I likely hit something hard with front wheel during descend so front can't be that soft.

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