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Tubeless tyre pressures - what do you ride?
Hi All,
I was after a bit of help and advice on tubeless tyre pressure.
I run a 26" dual suspension (5") bike with XT wheels and Nobby Nic's (F&R), I weigh 85-90kgs with gear.
I would say I'm an average rider who rides all of the popular trails on the Northern Beaches, I can do all of the obstacles on the dam and usually ride a sub 40min lap.
I have been experimenting with the pressures but I think I have them too high, something highlighted today by the fact I rode Duck hole, Waratah and Centre Track with my rear tyre pressure at 20Psi!!
Let me know what you run and/or what you think would be a good starting point.
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i think you will get alot of answers to your question but the right one is what feels good for you
i run on my AM bike
2.35's on the front with 30psi
2.1's rear with 34psi
have them in tubless configuration and that seems to work really well for me. ride mostly red hill northern beaches.
tubless vrs tubes also makes a big difference in the answer i think
I'm about 85kg kitted up for the ride, maybe a couple kg less now.
I run NN front, RR rear, both 2.25 and tubeless and on a 5" travel endurance race bike (Cannondale Rize). I run mine at 22-25psi front and 28-32 on the rear.
Any less either end and it starts to get squirmy, any more than 25 and the NN's get skatey. With Maxxis Ignitors 2.35 / Larsen TT 2.0 combo I used to run 28-30 in the front and 28-32 in the rear and found this combo and pressure very good in most conditions.
Pressures depend on trail conditions. If it's smooth and groomed I run higher pressure on the rear, if the surface is rougher or dusty and loose I run lower unless squirm becomes a problem and then I start to lift it again. Front pressure I don't change much.
I'm about your weight. I use the NN at the front, RR on the rear. Mine are snake skin TLReady set up as tubeless.
I need to run the NN at around 30psi when going through Manly dam. I've had a few burps loosing pressure hitting bumps on the downhill sections.
Most other places I do around 28
On the rear I do 30 as well. I've been getting holes through the tread quite a bit from going through centre trail & Duckholes. Usually they seal up after a while.
Mind you I got a puncture through the tread at spit junction yesterday just standing there. It just hasn't sealed. Is it possible the tyre is toast?
And the biggest factor in your question is what datum are you measuring the pressure against. A recent thread highlighted the fact that pump gauges often vary in reading between brands by large margins.
After years of playing around with tyre pressures, and not really listening to what others suggest, I think it comes down to what feels and works best for your particular circumstances. Pick one device, then calibrate (or compare) all your pumps and gauges against that so you can repeatably set pressure on the go, or know where you are relative to the base line when experimenting... Or if the budget allows, get yourself one good quality portable pressure gauge and use it for everything.
I'm with Slowpup on this. I tend to find its how the bike feels to you. Its exactly like setting the pressures in your forks and shocks. I know some people that run high pressures in their tyres but have a softer set up in the suspension. I know other people that run soft pressures in both. I tend to run slightly higher pressures all round. Its a really hard one. I would take tyre pressure recommendations and then tweak to suit yourself, same as suspension set up.
Cheers
Evan
That comes with experience, though, and a bit of an analytical brain. Some of my experience has come from making mistakes (eg, not topping up before a ride) and find out that it was better in some circumstances, and not so good in others, and then being curious and measuring.
A lot of beginners don't know what "good" should feel like, so it's a bit hard for them to judge whether a change is an improvement. heck, after 6 years I still don't know what "good" feels like.
I would need to ride a "good" rider's bike who is the same weight as me to get a feel for it.
I have to admit once I find something that works I tend not to vary it too much. I have a digital gauge. It seems to be consistent with my other analog gauges on other pumps so I'm happy to call it accurate.
Would someone else like how my bike behaves? Probably not, but I have no idea.
I find the thumb index squeeze test better than anything else.
You'll soon enough work out how much squish works for you.
Not being a smartarse BTW but guages are less reliable IMO.
Hi All,
Thanks for your comments.
I understand what you mean when you say 'what feels right for you', obviously 20psi was far to low but still it didn't seem to have that much (negative) effect and it really did grip! (the tyre is a Snake Skin so it is a little stiffer)
I used to run the same tyre with tubes at about 32-34psi so I might start experimenting around the 26-30 mark and see how I get on.
I'm using a cheap BBB floor pump and I reckon the gauge is probably not that accurate and 10psi increments are measured over about 5mm, so it's pretty hard to tell where you're at with the pressures.
Does anyone have any suggestions for a floor pump with a MTB specific gauge? I had a look at a specialized one today which only went up to 70psi and it was much easier to see the incremental steps in pressure. Instead, I guess I could invest in a decent stand alone gauge however I have a car one which would be perfect for the job but I doubt I could modify it to fit on the valve stem and achieve a meaningful reading.
What pumps/gauges work well for you?
I have the BBB digital gauge, as my Topeak fllor pump only has 4psi gradations, not the most confidence inspiring for acccuracy or consistency at low pressures. From memory it was under thirty bucks.
My other pump gauges would be within 3-5% I reckon
Edit: the gauge i'm talking about is a separate gauge, small emough to fit in my camelbak and weighs just a few grams. No pump attached.
If you can't squeeze the tyre using your thumb, or the depression it makes is barely a depression, you're out of range. If you get that opposable thumb touching it opposite, you're out of range.
What's left is your goldilocks zone. Unless you have huge 2.5+ hoops, keep dropping the pressure till you bottom out on the rim too often. I've ridden with some DH riders that run 10psi with rock solid rims - they've always got grip. On my XC bike, I run 2.3's at 18psi and only occasionally bottom out but it isn't a problem as I run carbon rims (they don't dent like my Al rims used to).
I think what Martin is saying is that you need to try a few different pressures and get a bit of experience to make a decision on what's 'good' for you.
We're both in WA, so grip is harder for us to achieve.
For me, I run a bike with Specialized captain controls and a bike with racing ralph snakeskins, both tubeless. I'm at the heavy end of the scale, weighing in at about 100kg. I can't run much lower than 30 psi for risk of burping my tyres, even though we don't have much grip. The lower the pressure, the higher the grip, but also the higher the risk of burps.
I race and consider myself to be a little bit faster than the average Joe, but nowhere near the elite guys. At this speed, I'm always searching for more grip. The only place I've had ample grip is Margaret River. If you have more than enough grip, then you can run a bit harder to reduce your rolling resistance and risk of burps or pinch flats.
Try a few different pressures out, find out what works best for you. BTW, 1 or 2 psi difference will do bugger all. Your tyres will change more than that by heating up and cooling down.
Apologies, should have mentioned:
I'm in WA where we ride on ball bearing gravel.
I weigh around 70kgs with a 11kg bike.
I run rims that have a flat section adjacent to the tyre bead hook before dropping into the spoke channel so burping isn't an issue (never had it burp, even at 15psi doing 1m drops off balance).
It does take a while to know what is good and feels good to ride. At 105kg + kit I generally run 32 psi in the front with a Nevegal and 34 psi on the back with a Racing Ralph. This combination feels about right for me, I'll drop to 30/32 psi for Knapsack if I'm going to session more than just flat out ride.
Im around 78kgs & run 18-20psi front & 23-25psi rear when I'm riding single track & want grip.
This is with Maxxis Ikon EXO 2.2 on Easton EA XC 90 UST rims on a 29er HT (10kg).
Never burped the tyres that I know of.
When riding firetrails ( eg Loftus RNP ) ill bump it up a bit to 23-25psi front & 30-32 psi rear.
On my 29er dually with Nobby nicks snakeskins i run 20-22 psi front & 28-20psi rear on Stans Crests.
Im a 125kg rider. I need to run my rear at 40psi, if less i can feel the wheel rolling sideways and potentially burbing. I run my front at 38psi but could pobably go a little less.
If your riding centre track and duck holes they are so rocky that its worth running a few extra psi to keep your rims in one piece. Lower pressures are reasonably dependant on tyre width. You didnt mention what size tyres however lower pressures will roll more efficiently and provide better traction than higher so lower is better, and you can go lower with wider tyres. On a 5" dually you should be on 2.25s, not 2.1s.
I have been running 20 or 22 psi at stromlo recently without any issues although I am a bit lighter than you. I expect most of the elites here at the xco nationals this week will be running pressures lower than I do.
Your mileage may vary.
while it depends a bit on the surface being ridden on, higher pressure generally makes for better rolling, lower pressure for better grip. The more that grip becomes important relative to rolling resistance, the lower the ideal pressure. Same applies to tyre width - the more width, the more rolling resistance but the better the grip (all other things being equal). The heavier you are, the more pressure you can run without sacrificing grip (again, all other things being equal).
Tyre choice and pressure choice depend on how you want to ride and what sort of surfaces you mostly ride on. Experimenting with pressures and tyres over time should get you in the right range for what you want to do on the bike.
Lach tend to disagree about rolling resistance and tyre pressure/grip. These links give some research results.
http://www.mckramppi.com/en/bike04rengas/Bike200... (some caution in interpreting this data is needed)
http://www.mtbonline.co.za/info/mtb-tyre-rolling...
http://www.schwalbetires.com/tech_info/rolling_r... (this article by Schwalbe has a table indicating the rolling restance of some of their tyres - but it may need updating)
To quote extracts from the articles:
"Off-road a reduction of tyre pressure reduces rolling resistance. In a meadow for instance going back from 4.0 to 1.5 bar (57 to 21 p.s.i.) can save remarkable 18 Watts of power."
"On an identical course and at exactly the same speed, the widest of the tyres tested here at 1.5 bar (21 p.s.i.) requires a solid 50 W less power than a narrow tyre at 4.0 bar (57 p.s.i.)."
another:
"The research team found no significant correlation between the grip and the rolling resistance of the tires"
"Anyone who wants to ride really fast off-road needs to decrease tyre pressure"
Articles list the tyres in order of rolling resistance (and grip)
Another article claims “- - - a bicycle with narrow tires is much easier to accelerate because the rotating mass of the wheels is lower and the bicycle is much more agile. At constant speeds of around 20 km/h, the ride is better with wider tires. In practice, the energy saving is even greater than in theory as the elasticity of the tires absorbs road shocks, which would otherwise be transferred to the rider and so saves energy.”
Choose a tyre to match your conditions, riding style and you have confidence in. Lack of confidence in tyres will result in slower riding.
FWIW - I'm in WA ride a 29r, currently specialized 2.2 wide, and ride between 22 and 25psi. But I'm relatively gentle on tyres (and slow!).
just to jump in here - i run my tubeless @ 28-30 F & R. all up i weigh (incl CamelBak etc) about 90kgs.
based on the numbers people have been discussing above, seems i could get away with running around the 25psi mark without too many issues..?
always keen for a bit more grip around Kala, esp in summer!
I admit I probably simplified the argument a bit too much. There are obviously differences related to the structure / compound of the tyre which impact on both grip and rolling resistance.
And it seems that the research supports a view that less pressure gives better (less) rolling resistance off road. Although measuring it on a meadow is hardly a typical off road surface. If I was riding in a meadow or on beaches or snow all the time I'd want a Pugsley with low pressure tyres. If I was riding mostly hard-packed fire trails, it would be a different story. Interesting to know whether having full suspension would reduce some of the energy disadvantage of higher pressures on uneven surfaces.
Anyway, I still think it comes back to what sort of riding you do as to whether higher or lower pressure is best for whatever combination of tyres, bike, terrain and riding style you are looking at.
Don't let the others know.....
We're like ... connected man! I had pretty much the same message written up but decided not to post it. Previous attempts to educate have, well, I feel like a science teacher in USA's south - you try to help and people thank you and tell you you're wrong cause 'we've always done it like that so your hard earned knowledge is not match for our intuition'....
I'm probably 5kg less UglyBob.
Using 29x2.30 tyres, I run the front between 15-18 and the rear a couple psi higher. 15psi is the very limit for my rim/tyre combo - I use 30mm wide rims which again, reduce the pressure you need to run.
If I were running narrower tyres, I'd up the pressure a fraction right in that range of 20-25 that you suggest. Really, the best way to find out is to keep dropping them and see where the tyre hits a sweet spot (might cost you a dent or two in the rim). You'll know it - seriously - the tyre will sound different.
Instead of the usual chattering, on, off sound of the tyre on the gravel, it will be a smoothing rolling shhhrrrr because the tyre will be in contact with the ground at all times, which equals more grip. Of course, according to Lach, each time your tyre isn't in the air, that's a rolling resistance penalty for you, but I'm sure you can live with that.
p.s. don't worry about trying to find grip though - it's not there at the KC. Well, not on the trail it isn't. The grip is in the secret berms - tree trunks, ruts, anything that's surface is not horizontal is a berm. You might be surprised at this, but I run the Specialized Renegade tyre (slick with pimples) and have no problem keeping up with (apologies for the lack of modesty) some pretty fast characters. I lose out slightly in flat corners (with no secret berms) but they are few are far between.
http://www.specialized.com/us/en/ftb/mtb-tires/c...
Ye Gods Renegades!!! Last time (the only time) I rode fast rollers on Pea Gravel I ended up going down a 17% grade with both wheels locked up and gaining speed, screaming! Ahhh but there ain't no steep DHs on the KC - hmmm.
Anyway I'm 74kg fully kitted in the rain. Trying out 29r Specialized S-works Ground Control, 2.3 and slowly dropping the pressure - now at 23psi. On carbon rims which are currently in for truing. ?!?
If Eastern Staters are not sure what Pea Gravel is, here's a pic, sometimes called ball bearing gravel.
thanks Martin. might try drop it to mid 20's this weekend, see how i go!
i'm running a nice fat hans dampf on the front at the moment, but have a renegade on the rear.
correct though re grip - not much to be had at the moment. looking like a bit of rain in the next few days, so hopefully some makes it out to kala for the weekend eh!
How deep does it go?-or is it just loose over a hard base?
Depends - can be anything from inches deep so that its up to the rim in some sections and no base, or it can be just one layer thick over hard base. Part of the problem can be the 'hard base' is composed of very fine grains and is unstable and contains more peas, so riding it just exposes and loosens more peas, so in some cases a 'cleared' line wont appear.
But after rain (and it hasn't rained for some time) the soil can compact or the fine dust is washed away, so its then probably the best grip we'll have.
All it takes is a power meter and some back to back runs in similar conditions to confirm what's better with pressures. Now does anyone have a spare MTB power meter?
Also it seems like you have another year as the 50k cyclenation champ. Enjoy!
Martin, I am currently using the 2.3 renegades on my 26in bike. There great.
I've got to where I am (such as it is) without power meters, heart rate monitors, or any understanding of science it seems, so I'm happy to rest on my laurels for another 12 months
In the meantime, to demonstrate that an aged mind can still be an open mind, I'll probably experiment with tyre pressures when I convert to tubeless ahead of an upcoming Central Australia trip. If only because I expect that the riding conditions there may just be a bit different to Sydney....
I've experimented with tyre pressures over a set course and found that 30PSI is fastest. Lower pressure is grippier and more comfortable, but slower overall. 35 PSI makes no improvement on speed (compared to 30 PSI) and grip and handling suffer so that it is slower overall. I ride a xc bike with tubeless tyres and weigh 88kg.
A significant improvement I made was to go to shorter cranks, 170mm from 175mm. As well as suiting my leg length better, it gives you more clearance over rough stuff, so overall speed improvement is significant.
Arrh! Beware the three-cornered jack! Take lots of sealant, and maybe consult a bike shop in the area for suggested tyres.
I've seen all the stuff on the Ingkerreke website re tyres, so am appropriately worried. Will convert initially with a set of LUST Crossmarks I've got, but will probably get something a bit fatter and thicker for the trip to Alice. I don't think mud-shedding ability will be an issue....
I wouldnt do the Alice event without tubeless conversion.
It would be mad.
FWIW I went all week without a single puncture on tubeless Ignitor/Crossmarks.
The locals there believe Continentals are better suited to their trails and tend to push those.