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Recommend me some tyre pressures please?

by downhiller
Mon, Feb 12, 2018 11:10
15

Wife and I about to go out for our first ride on our new bikes.

She's 57kg kitted, I'm 90kg kitted.  She's on 28c (Vittoria Rubino Pro) and I'm on 25c (Michelin PRO 4 Service Course).

Using the 45% / 55% weight distribution aiming for a 15% drop that seems to suggest:

Her
front: 37psi
rear: 50psi

Me
front: 73psi
rear: 96psi

I guess mine "feel" about right, but hers seem too soft, surely?

What'd you recommend, and why?

Ta!

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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15 comments

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kma55 | 7 years ago
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Last summer I was down to 60kg running 28mm tyres, I had 80psi rear, 75 psi front.

Used this as a guide:

https://www.schwalbetires.com/tech_info/inflation_pressure

I was also bored enough to use the information from the table on that site to create a multiple linear equation so that different tyre widths and rider weights can be used:

psi  =  97  -  1.84*Tyre Width (mm)  +  0.57*Rider Weight (kg)

I would use the result from that for the rear, then drop the front by 5-10 psi.

Avatar
downhiller | 7 years ago
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We are also in Shropshire - yesterday's ride certainly varied from potholey lanes to glass-like smooth new tarmac coming into Leintwardine 1

Avatar
Simon E replied to downhiller | 7 years ago
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downhiller wrote:

We are also in Shropshire - yesterday's ride certainly varied from potholey lanes to glass-like smooth new tarmac coming into Leintwardine 1

Hola!    That sounds nice (the new tarmac bit).

Clubmates were discussing the parlous state of our local roads on Monday. The only reliably smooth tarmac near here is over the border in Powys. I'm not sure if it's due to better maintenance, lower traffic volumes or a combination of the two but most of the roads there are in considerably better condition than in the Shire.

Shropshire council is too busy buying shopping centres in the town (why? no-one knows) and pissing away money on a Shirehall refurb and the stupidly expensive relief road instead of spending it on boring things like public services or resurfacing.

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Simon E | 7 years ago
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I'd start with psi of rider weight in kg, add 10 psi for rear tyre.

Her: 60 / 70 psi

You: 90 / 100 psi

Adjust 10 psi either way.

I'm probably 65kg kitted up and usually inflate to about 70 psi for everyday riding with 23 or 25mm 'allrounder' tyres (Durano / Pro4 Endurance / Lithion etc). Happy to let it drop to 50-ish before pumping up again. It used to be 80+ psi but too much vibration and bumps being transmitted from the road.

Race tyres (Ultremo 23mm) 85-95 psi, depending on road surface, which in Shropshire varies between poor and diabolical.

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check12 | 7 years ago
1 like

I'd say without measuring tyres for actual width and having an accurate way to measure pressures it's all a bit of trial and error, start sensible like you have and go up or down 5psi at a time, thought your pressures seem towards the bottom of what's ok for road pressures. 

My pump read 10ish psi high and my 23mm tyres measure 26mm!

 

Avatar
downhiller replied to check12 | 7 years ago
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check12 wrote:

I'd say without measuring tyres for actual width and having an accurate way to measure pressures it's all a bit of trial and error, start sensible like you have and go up or down 5psi at a time, thought your pressures seem towards the bottom of what's ok for road pressures. 

My pump read 10ish psi high and my 23mm tyres measure 26mm!

 

 

You make a fair point on the widths - I think I've read that my Michelins come up closer to 28c size.  As for the pressure I have a couple of consistent digital guages (you have to have at least 2 otherwise to give a bit of confidence that the numbers they show might be accurate!)

Avatar
Boatsie | 7 years ago
1 like

We're lucky at the moment. Our government supportive of cycling. Lots of fresh layer bitumen with dedicated bicycle lanes. Hard and smooth. Never really needed to run soft and too scared too although having realized the rims were worn.
My mate was rolling hard, never below 120psi even if Max read 110. Took a while to convince him that 100 was hard enough. I am amazed that lower pressures are rolling reliably. Congratulations, an admirer.

Avatar
Canyon48 replied to Boatsie | 7 years ago
4 likes

Boatsie wrote:

We're lucky at the moment. Our government supportive of cycling.

I wish we could say the same here in the UK!

Avatar
Boatsie replied to Canyon48 | 7 years ago
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wellsprop wrote:

Boatsie wrote:

We're lucky at the moment. Our government supportive of cycling.

I wish we could say the same here in the UK!

The Welsh support cycling.
Muscles are similar use to kayaking and the big red dragon is there for dumb arses like me that bang heads on the old copper miners front door envelopes; argh look, approaching port, drag on.
I love your tow paths although I would prefer wider tyres if a resident. Neighbours are closer too hence just ride there.
English seem to support cycling in their own way since a great king of yours was sucked in by a Rothschild. Eg. Tax high the cars entering London and grow you guys tough. That's pretty awesome how some of you ride many miles each day.
I'm jealous, I like your countries. Please protect the Irish, they have a beautiful Atlantic ocean.
Lol dragons exist.
https://m.facebook.com/story.php?story_fbid=2007983582563545&id=21829931..."218299314865323"%3A%7B"page_id"%3A218299314865323%2C"role"%3A1%2C"actor_id"%3A100000586585301%2C"psn"%3A"EntStatusCreationStory"%2C"attached_story"%3A%7B"page_id"%3A218299314865323%2C"role"%3A1%2C"actor_id"%3A644732809%2C"psn"%3A"EntGroupMallPostCreationStory"%2C"attached_story"%3A%7B"role"%3A1%2C"page_id"%3A218299314865323%2C"post_context"%3A%7B"story_fbid"%3A2007983582563545%2C"publish_time"%3A1517387437%2C"story_name"%3A"EntVideoCreationStory"%2C"object_fbtype"%3A1%7D%2C"actor_id"%3A218299314865323%2C"psn"%3A"EntVideoCreationStory"%2C"sl"%3A4%7D%2C"sl"%3A4%7D%2C"sl"%3A4%2C"targets"%3A%5B%7B"page_id"%3A218299314865323%2C"actor_id"%3A100000586585301%2C"role"%3A1%2C"post_id"%3A2007983582563545%2C"share_id"%3A0%7D%5D%7D%7D%3Athid.100000586585301%3A306061129499414%3A2%3A0%3A1519891199%3A-4195560087701298385&__tn__=CHH-R

Avatar
Canyon48 replied to Boatsie | 7 years ago
4 likes

Boatsie wrote:
wellsprop wrote:

Boatsie wrote:

We're lucky at the moment. Our government supportive of cycling.

I wish we could say the same here in the UK!

The Welsh support cycling. Muscles are similar use to kayaking and the big red dragon is there for dumb arses like me that bang heads on the old copper miners front door envelopes; argh look, approaching port, drag on. I love your tow paths although I would prefer wider tyres if a resident. Neighbours are closer too hence just ride there. English seem to support cycling in their own way since a great king of yours was sucked in by a Rothschild. Eg. Tax high the cars entering London and grow you guys tough. That's pretty awesome how some of you ride many miles each day. I'm jealous, I like your countries. Please protect the Irish, they have a beautiful Atlantic ocean. Lol dragons exist.

Ok............ sad

Avatar
downhiller | 7 years ago
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Tubed, yes.  I'd like to switch to tubeless though, as a mountain biker and an early adopter my other bikes have been mostly tubeless since 2001!

On the subject of this thread there were no replies before we headed out so went for 45/60 for my wife and 75/90 for me.  Seemed a-ok, and much more comfortable than my last foray into road biking 5-10 years ago where I felt dutybound to inflate to the maximum pressure of 115psi or whatever my tyres were rated to!

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Boatsie | 7 years ago
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Why? My 10 year old road bike cost $200 new, hence imagine quality level. Majority of flats were from low tyre inflation and some from over inflation. Very few from not far below Max.
Last night I was giggling because I have 3 sets of quality tyres and 1 set of cheap near rubbish tyres therefore not wanting to waste 2 new tyres I allocated 1 to the front rim. The rim is worn from braking and I've been watching such waiting for daylight to appear on the tube but trying to fit the cheapy last night found the tyre was too big a diameter on the rim. I thought the tyre was gone but I changed rim to an older track rim and fitted perfect.
So getting back to pressure, I find that when rolling tubed tyres I read the recommended pressures written on the walls of the tyres. They are a God send. Some have min to Max where I basically shoot at the middle. Others with only maximum written I blow 10-20 psi below to allow rolling variables to safely increase initial pressure while staying below maximum.
I found that rolling low pressure with tubes created a lot of bead punctures during the journeys.
I find that with pressure higher the vibration is increased. I still think your better off just below Max a week or two and adjusting from there. I have no idea regarding tubeless. Just disliked bead puncturing a lot of tubes.
My 28s I roll at 100psi(Max110).
The cheap 23 on front is at 95psi(Max 110).
The back end takes a lot more beating than the front. I weigh 96kg on a 11kg bike =107kg.
Aware that your rims are probably higher quality than a cheap 10000+km rim. Starting at 20 below maximum shouldn't hurt and give you couple a steady unit of measure to adjust from.
(Warm, dry, summer at the moment, grip plenty, never really slippery around here)
Best of luck

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lavds | 7 years ago
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Good app from Vittoria www.vittoria.com/itire/

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peted76 | 7 years ago
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I presume that's tubed.. I run tubeless 25's and 28's, I'm 74kgs.  Consider inner rim width also.

Personally 25mm = anywhere between 80-90 psi depending on weather and distance. I will only have a 5psi difference front to back so that'd be 85/90 psi for a short fast ride. 28mm = my general rule is about 10psi less.  I acknowledge people can run really low pressures, and I have tried lower also, but this generally suits me for most of the rides I'm doing. 

 

For your wife, I'd go 60/65psi, I don't know what it's like to be 57kg's but my thinking is that cornering may get a bit squirrely, which isn't a nice feeling. 

Avatar
Canyon48 replied to peted76 | 7 years ago
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peted76 wrote:

I presume that's tubed.. I run tubeless 25's and 28's, I'm 74kgs.  Consider inner rim width also.

Personally 25mm = anywhere between 80-90 psi depending on weather and distance. I will only have a 5psi difference front to back so that'd be 85/90 psi for a short fast ride. 28mm = my general rule is about 10psi less.  I acknowledge people can run really low pressures, and I have tried lower also, but this generally suits me for most of the rides I'm doing. 

 

For your wife, I'd go 60/65psi, I don't know what it's like to be 57kg's but my thinking is that cornering may get a bit squirrely, which isn't a nice feeling. 

Wot 'e sed - more or less

I'm 67kg, on my road bike, I usually use 90 rear and 85 front for the 25mm tyres. On my commute/winter road bike with 28mm's, I use 65 rear and 60 front (I add 5psi to that if the road conditions are good).

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