Tyre pressure

Roadracer123

seems like a foolish question but i've recieved different advice, one person advises i make the tyres as hard as possible, and another says they should have a little give in them, help please?

ilm_zero7

depends what you are riding on - if its a track an good even surface right to the max specified on the tire would give optimum (min) rolling resistance, but its a hard ride and a little softer in the wet and poor quality roads may keep you aboard and less puncture prone

Scrumple

a little less air will be more comfy, and softer, and less harsh a ride.
more air will roll faster, but will show up the bumps.

Some think more air resists pun@ture# while some think less is best. I go high.

rake

90 front, 110 rear.

Roadracer123

Thanks everyone

rick_chasey

6 bar.

Brits are well known to have a thing for over-inflated tyres!

plowmar

Ten below max for tyre on rear and a further ten off front, gives best of both worlds.

Hard tyre resits snake bite punctures but as I've had other punctures will not guard against thorns or slivers of glass as they tend to work their way through.

1_reaper

I run 120 in both front and rear but lower the pressure if i'm going on one of my training routes with crappy roads

inseine

Depends on the roads and how much you weigh. Make sure you have a gauge so you can repeat accurately when you've found what works.

Barteos

http://www.vintagebicyclepress.com/images/TireDrop.pdf

desweller

You should also note that your air pressures will vary depending on what the width is of the tyres you are running and how heavy you are.

For instance, someone who's 75 to 80 kg might typically run 23mm tyres, 90psi front and 100 psi rear. This will give quite a firm ride but will offer good protection against pinch flats.

I'm 95 kg so I run a little more air than that, 110psi front and 120 psi rear (the calculation actualy suggests 114psi front and 126psi rear, but if the gauge on your pump is that accurate then you've spent more money on it than I have on mine!).

If I were running 28mm tyres then I would be able to drop to 90psi front and 100psi rear (roughly speaking) due to the increased size of the contact patch.

vanguard09

Im running both of my tires at 6 bar, im 77kgs, so does this sound sensible??

Headhuunter

I'm 80kg and I generally have 110-120 in the rear and about 110 in the front

inseine

Im running both of my tires at 6 bar, im 77kgs, so does this sound sensible??

Well depends on other factors like I said, but if you're on a road bike with 23mm tyres and normal roads it's not enough. Go up to 7 and see how it feels, though that would normally be a minimum.

UpTheWall

Michelin tyres come with a nice little chart with each tyre to say what pressure to put them at depending on a) rider weight b) front or back tyre.

So 3 variables - the 2 above, and manufacturers recommendation given how they made the tyre.

Comfort may be an issue, but I'd say the bike should be set up to handle that.

if it's not inflated properly you're *more* likely to get pinch pnctures.

rick_chasey

vanguard09 wrote:

Im running both of my tires at 6 bar, im 77kgs, so does this sound sensible??

Ya is good.

Esp on English roads.

We're not all riding on the slick French roads!

inseine

Ya is good.

Esp on English roads.

We're not all riding on the slick French roads!

We could both be right, depending on the variables, but I still think I'm right

CiB

I used to run front & back at 110 but now have them a bit less at around 100psi and the puncture resistance hasn't altered [touch wood none yet on these Pro 3s], but the ride is much more comfortable. Experiment, but don't run too soft as that exposes the risk of snake bites.

asprilla

You should take the combined weight of you and the bike into account as well since that's what is deforming the tyre.

UpTheWall

CiB wrote:

I used to run front & back at 110 but now have them a bit less at around 100psi and the puncture resistance hasn't altered [touch wood none yet on these Pro 3s], but the ride is much more comfortable. Experiment, but don't run too soft as that exposes the risk of snake bites.

As in Michelin Pro Race 3s?

I used to use them for quite some time. I found they punctured too often so I switched to conti' 4000s / 4 season for winter and found them much more reliable, at the same pressures.

And no appreciable performance difference.

Roadracer123

Another stupid question:
Will these shoes,
http://www.evanscycles.com/products/specialized/bg-primo-shoe-ec019812
be compatible with these pedals

http://www.evanscycles.com/products/shimano/m520-spd-pedals-ec005948?query=SPD
and are these the right cleats for those pedals?
http://www.evanscycles.com/products/shimano/sh52-spd-cleats-m858--ec005329?query=SPD%20cleats
If not can you please tell me which shoes and cleats i need for these pedals?[/url]

CiB

UpTheWall wrote:

CiB wrote:

I used to run front & back at 110 but now have them a bit less at around 100psi and the puncture resistance hasn't altered [touch wood none yet on these Pro 3s], but the ride is much more comfortable. Experiment, but don't run too soft as that exposes the risk of snake bites.

As in Michelin Pro Race 3s?

I used to use them for quite some time. I found they punctured too often so I switched to conti' 4000s / 4 season for winter and found them much more reliable, at the same pressures.

And no appreciable performance difference.

Yep - pair of Michelins. They're puncture-proof to the extent that I haven't had any punctures on these but had loads on the OEM fittings - Continental Sports IIRC, but who knows. More likely it's summer so there's less rain to wash sharp pointy things out from the gutters into the road. Ask me next March.

Headhuunter

Roadracer123 wrote:

Another stupid question:
Will these shoes,
http://www.evanscycles.com/products/specialized/bg-primo-shoe-ec019812
be compatible with these pedals

http://www.evanscycles.com/products/shimano/m520-spd-pedals-ec005948?query=SPD
and are these the right cleats for those pedals?
http://www.evanscycles.com/products/shimano/sh52-spd-cleats-m858--ec005329?query=SPD%20cleats
If not can you please tell me which shoes and cleats i need for these pedals?[/url]

Yes, yes and yes....

furrag

I recently read on my club forum:

Add the weight of your bike and yourself (in KG) and divide by 10 for your optimum tyre pressure in Bar. Convert to PSI by typing into Google search "6 Bar in PSI".

So for example, I'm 65kg and my bike is 8.3kg. That's 73.3kg / 10 = 7.33 Bar. That's 106 PSI.

UpTheWall

Furrag wrote:

I recently read on my club forum:

Add the weight of your bike and yourself (in KG) and divide by 10 for your optimum tyre pressure in Bar. Convert to PSI by typing into Google search "6 Bar in PSI".

So for example, I'm 65kg and my bike is 8.3kg. That's 73.3kg / 10 = 7.33 Bar. That's 106 PSI.

Nice rule of thumb.

The question is, do you have to let some pressure out of your tyres when you've drunk all your water...

And what about the affect of altitude?!

Ok, so I'm being a bit flippant, sorry! But I guess I'm saying that it's not going to be exact, so 10psi either way wont make too much difference.

CiB

I weigh 13 st 12 = 88Kg, + 8 for the bike = 96Kg = 9.6 bar = 139psi. errr - no thanks.

inseine

Ok, so I'm being a bit flippant, sorry! But I guess I'm saying that it's not going to be exact, so 10psi either way wont make too much difference.

By the above formulae 10psi would account for about 7kg change.
I always use a round 100psi for normal riding and the formulae says 96 so not too far out. Not surfe my gauge is accurate enough to judge 4psi!

vanguard09

I did that formulae and I would be running my tyres at 120 psi, that a bit of a harsh ride??

Think I will stick to 100psi, harder than im running them now, with (hopefully) a little bit of give!

furrag

The formulae has been known to be off for some riders.

My calculated psi is 106, but I ride at 120psi. I find it harsh on the very bumpiest of roads where I tend to bounce, but on the nice roads I feel quicker at 120psi. It could be all in my head though...

paulorg

I'd go for 100psi on the rear and 90 on the front just because there will be less weight on the front tyre so they'll feel the same, if its too painful when going over the bumps drop it a little but as others have said if it goes too low you'll run the risk of pinch p********. I'd suggest tyres such as Vittorio Rubinos or the like with a kevlar layer as they give awesome puncture protection without much of a drop in performance, I've been running them for nearly 4 years on various bikes without a p*******.

On the pedals/shoes/cleats issue yes to all, but you shouldn't have to buy separate cleats, they should come with the pedals. Personally I'd go with SPD-SL's or Look Keos just for the wider platform but again thats personal.