Help with tyre pressures

[Chris ledger]

Hi bit of advice required please on tyre pressures.
I was under the impression that running lower tyre pressures on tubeless would give more grip harder pressures give better battery life but less grip in corners.
Had the bike on 20psi at the weekend on dry stony dusty trails amd the front especially felt like there was little grip and struggled to turn in almost feeling like it would wash out.
Any advice would help thanks.
Riding a giant reign e+× 2022

 

[dobbyhasfriends]

so many variables..
sounds like your sidewalls are squirming and sidewalls make a big difference to what pressures you can run.
as an example.
I was running DH casing maxxis tyres at 24/28 with no problems
put on some gravity casing schwalbe tyres and I cant run less than 28/32 without squirming and burping sealant.
I definitely get more grip if I drop the pressures but at the cost of that squirming and burping.
cant say ive noticed a significant range advantage between pressures.. although the combination of pressure, compound and surface have an impact for sure..
like i say, so many variables

 

[Chris ledger]

Front tyre is maxxis minion dhf exo + and a high roller on the back its a lack of the front end grip that doesnt inspire confidence

 

[Chris ledger]

Thanks ill give that a go

 

[dobbyhasfriends]

Front tyre is maxxis minion dhf exo + and a high roller on the back its a lack of the front end grip that doesnt inspire confidence

if youre ringing the bikes neck a bit youll probably need doubledown as a minimum, depends on weight and terrain..
if you wanna run low pressures that is.

 

[Mikerb]

If we are talking a bout 29er wheels today I rode with 24 front 26 rear .Front is Assegai EXO+ max grip, rear is DHR11 DD max terra. That was on forest trails which are hard pack with a dusty top at this time of year and lots of exposed roots. I normally run 22/24 when the trails are wetter which gives better grip but I believe you need somewhat higher pressures to scrub though the dusty layer this time of year.

 

[Dax]

Bend your elbows. Try to be lighter on the bike and less rigid. Get off the brakes.

20psi is around what I run with a 2.4 27.5 assegai on my patrol for loose dust and rock, I’ve found it washes out early compared to the Mary’s and butchers I run through winter so it’s a bit less air than I’d normally go for. I’m 75kg ready to ride. It’s not an exact science for me, I just tweak pressures until the bike feels fun and handles right.

 

[KnollyBro]

Dobby is on point here. The only ones who can run that low PSI are riding to enjoy the scenery and not trying to shred anything near their bikes limits.

side wall, body weight and riding style/terrain are 100% what drives your pressures.

my general rule of thumb:
enduro / nothing crazy dh22/25
DH 25/27
Freeride 30/35 or more
That’s with me at 210lbs

While I try to enjoy the scenery as much as possible when running low tire pressure, my experience has been different but based on different goals. For instance, it was my experience that with DH casings in the bike park on 26" wheels, I was running 20 PSI with heavy DH tubes. I will admit it was for better grip and to reduce the stress on my arthitic wrists and I mainly enjoyed tech trails. I also will admit I had to pedal like crazy to keep up to my Bros on Aline (NOT my favourite trail!!!) and I used to put in a few significant dents into my Mavic 729 rims every year and had to rebuild rear wheels every couple of years!
Now that I run tubless with Cushcore (Assagai DD Maxxgrip Front and DHR II Maxxterra DH [bike park] DHR II Maxxterra DD [everywhere else I have to pedal] my pressure are F:17 R:19 @ 86 Kg body weight. I have never burped a tire and I probably don't ride fast enough around berms anymore to notice much in the way of tire squirm. I think Cushcore makes a huge difference. In 3 years with an emtb, I have not dented a rim which is worth the cost and fuss of Cushcore and replacing a rear tires when they start to show vertical stress tears on the side knobbies. Since I run a mullet setup, my front tire seems to be doing well with plenty of life left in it.
In the end, I don't believe in hard rules for tire pressure, only compromises in speed, longevity, traction and comfort all of which are highly dependent on the types of trails you ride and the location you live in. Your goals will also age and injury dependent! My choice is traction and comfort as I am 60 and break easy.

 

[RustyIron]

Had the bike on 20psi at the weekend on dry stony dusty trails amd the front especially felt like there was little grip and struggled to turn in almost feeling like it would wash out.

As has been suggested, your pressure might be too low.

Although this is just my subjective opinion, I think you get better traction when the tire is pumped up and you're on the side knobs, rather than when it's underinflated and the carcass is rolling under. A good thing about a tire that isn't all squirmy is that it's more predictable. Disclaimer: I don't ride in mud or the rain, so just ignore this if that's where you ride.

Just for comparison, on my everyday bike, up front is a 29x2.5 Assegai at 27 psi. Out back is a 27.5x2.4 Dissector at 30 psi. I tip the scales at 196 pounds.

 

[urastus]

Well, only to show how different we all are and all the other variables. I'm also around 196 pounds. It's generally dry, rocky and steep, and I do some smaller jumps, gap jumps and drops but I'm still learning so sometimes I land front or rear heavy and bottom out that end. I have 29x2.5 dhf exo front and 27.5 x 2.6 dhrII exo rear. I run 17psi in the front with a tube, 19psi in the rear with a tannus insert. I never get pinch flats. I usually run tubeless in the front, when I do I actually run more pressure @ 19psi.

 

[Dax]

I run 17psi in the front with a tube, 19psi in the rear with a tannus insert. I never get pinch flats.

How?!

 

[VWsurfbum]

This is all subjective to too many variables, plus the accuracy of your pressure gauge.

 

[skinipenem]

Reading between the lines here to OP. If you don't notice the lack grip vs squirming of higher vs lower pressures... and as stated the front dhf doesn't grip well...perhaps the following is occurring.

The dhf will drift in the no man's zone of intermediate bike lean. In other words, that tire grips upright and aggressively leaned over, but not in-between.

This is based on my experience and others; however, I haven't ridden a dhf in years so perhaps the lug layout has changed.

Looks like it hasn't changed significantly. See the empty space between side knobs and braking knobs? That's the fun drift zone. Super fun on front and rear to purposely drift and then hookup, but not for intermediate lean grip.

The other picture is the assegai which, in contrast to the dhf, has intermediate knobs.

If this is your problem, then lean the bike over more or get a different tire. Then play around with pressure and see what feel you prefer.

And unless you way as little as my wife riding then 20psi might be bit low in the front even for xc/trail riding especially without an insert. Might feel squirmy/wallow and not nimble.

 

[RustyIron]

the accuracy of your pressure gauge.

^^^THIS

The pressure gauges we use are junk to begin with, and we abuse them by using them on tires that contain sealant.

 

[KnollyBro]

^^^THIS

The pressure gauges we use are junk to begin with, and we abuse them by using them on tires that contain sealant.

I totally agree. I have a few guages that read different pressures but the two that match are my floor pump and the one I bought off Amazon shown below. I know I run low pressure (elbow sqeeze test on hard ground) but I defininitely tell when its too high as I feel my tires bouncing and slipping off rocks and roots. I look as low pressure as an extra 50mm of suspension and my wrists thank me for it .

 

[steve_sordy]

Buy a digital tyre pressure gauge like the Topeak D2 Smarthead Digital Tyre Pressure Gauge. Like this one:

Topeak SmartHead Digital Gauge D2

Buy Topeak SmartHead Digital Gauge D2 at Tweeks Cycles. Shop the biggest brands with confidence and enjoy rapid worldwide delivery & 365 day returns.

www.tweekscycles.com

I cannot guarantee how accurate it is (reports say it is), but it is consistent and will last for years. Presta and Schrader valves, three different pressure units (psi, metric and SI), small coin battery that lasts ages.

Next time you ride, take your mini-pump and the gauge. Try a few trails/corners/rough bits/whatever. Then if you don't like the feel, measure the pressure and then add or remove 2psi. Repeat until you are happy. +/- 1psi can make a lot of difference. For example, I discovered early on that tyre pressures set in my cool garage feel noticeably different when out in the sun (the pressure goes up).

it does not take long to zero in on something that works. Maybe a few more trips out to confirm. You will soon get a feel for what pressures work in certain circumstances and what tyre "feel" works for you.

 

[Chris ledger]

Thanks for all the comments psi up in stages and give it a go

 

[KnollyBro]

I still wonder how much sealant gets into the tire guages and affects the readings. I know I can take it apart and maybe clean it out. Its the putting it back together that would be the problem.

 

[steve_sordy]

I still wonder how much sealant gets into the tire guages and affects the readings. I know I can take it apart and maybe clean it out. Its the putting it back together that would be the problem.

When parking the bike when back home, or on the bike rack, I always position the tyre valves at the bottom. The intention is for any latex to drip off the valve intake. It works to some extent because it can take a year before I get problems with taking pressure readings. So far, it is the valve intake that gets blocked; so far, I haven't had problems with the Presta valve core. I may have been lucky, but I have never had problems with the gauge.

 

[RustyIron]

I haven't had problems with the Presta valve core. I may have been lucky, but I have never had problems with the gauge.

My air flow gets slower and slower over time. When it becomes noticeable, the next time I have the valve guts removed, I just throw the old one as far as I can and install a new one. Amazon has them for $9 for a bag of twenty.

Your Topeak gauge got me thinking... they're a big company, so if the gauge gets buggered by sealant, I can get it warrantied. I checked their warranty, and it's two years. Not shabby. Then I checked Blackburn, which has a lifetime warranty. One reviewer complained, and I confirmed it with Blackburn customer service, that their gauges have to be reset if you're bleeding air out of the tire. I guess I'll be getting the Topeak.

 

[steve_sordy]

My air flow gets slower and slower over time. When it becomes noticeable, the next time I have the valve guts removed, I just throw the old one as far as I can and install a new one. Amazon has them for $9 for a bag of twenty.

Your Topeak gauge got me thinking... they're a big company, so if the gauge gets buggered by sealant, I can get it warrantied. I checked their warranty, and it's two years. Not shabby. Then I checked Blackburn, which has a lifetime warranty. One reviewer complained, and I confirmed it with Blackburn customer service, that their gauges have to be reset if you're bleeding air out of the tire. I guess I'll be getting the Topeak.

The Topeak D2 is designed to bleed air out, it has a handy button that does exactly that and gives flashing readings so that you can observe the air pressure as it reduces. It is not quite as perfect as I have made it sound, but close.

 

[Tubby G]

The Topeak D2 is designed to bleed air out, it has a handy button that does exactly that and gives flashing readings so that you can observe the air pressure as it reduces. It is not quite as perfect as I have made it sound, but close.

I have the Topeak. I initially overinflate, then let air out using the bleed valve to get the required psi

Quicker than pumping, taking a reading, pumping again, taking another reading etc etc

 

[Long Way Home]

Hi bit of advice required please on tyre pressures.
I was under the impression that running lower tyre pressures on tubeless would give more grip harder pressures give better battery life but less grip in corners.
Had the bike on 20psi at the weekend on dry stony dusty trails amd the front especially felt like there was little grip and struggled to turn in almost feeling like it would wash out.
Any advice would help thanks.
Riding a giant reign e+× 2022

So many variables, but the most important ones to take into consideration are total bike and rider weight, tyre size and ride surface. Lightweight bike and rider combos can totally run on 20psi, but this would be with larger volume tyres. Loose and dry trails could give any setup a sense of understeer though.
As some idea, my total riding weight is less than 90Kg, I have 2.4" 650b tyres (Maxxis Minion DHF/R) 22/24psi or thereabouts. All other factors being the same, running tubeless will make no difference in terms of grip, but rolling resistance will be less.
You need enough pressure to support the bike and to maintain tyre form, so it's a case of raising pressure until the ride is improved. You'll find that you might need to adjust your pressures depending on your tyre choice, terrain and weather conditions.
By the way, if you run tubeless and drop the pressures too low, your rims are at risk of damage...

 

[michael.kozera]

as mentioned already, but ive noticed most ppl run way too low of a tire pressure. the marginal gains you get from running below 25psi is laughable sometimes, and the risk to your rims and loss in cornering stability is greatly increased.

if you have to run 20 psi to " have enough grip" then perhaps the issue is not the pressure, but the lack of rider skill and wrong type of tire.

ebikes are heavy and alot of modern tires are wide/ large volume , so sure, if its wet i might go down to f-20 r-25 psi sure. but normally f-30 r-35 psi works great for "most terrain" with "most tires" with "most rider weights"

hope this helps.

 

[emtbPhil]

As has been said - tons of variables

HOWEVER I fell into tubeless means you can run lower pressure, lower pressure means more grip. It's really not that simple
I was running 20 psi and the bike wasn't great, especialy on stuff like Dalby red trail.
I watched a few videos where people said start with around 26psi - so I run 26psi rear and 24psi front now and it's LOADS better

If you're doing flat trail stuff go higher.
The thing is the bike is pretty heavy and I'm pretty heavy and I think the lower pressure = more grip stuff doesn't work when the tyre starts squirming around on the rim.

 

[Chris ledger]

Im 15 stone running 2.5 and 2.4 tyres tubeless so pumped up to 25psi and give that a go

 

[dobbyhasfriends]

Im 15 stone running 2.5 and 2.4 tyres tubeless so pumped up to 25psi and give that a go

I should have added my weight to my original post.
im also 15 stone in riding gear.. 25psi is a good start but you may have to go higher in the rear.

 

[LeeS69]

Bit late to this post but I'll put my bit in

I ride near the Pennines (UK), woods, moors, rocky tracks with water bars etc. Not DH or throwing myself of big drops etc but I do like to go fast. On my hardtail normal bike with Hans Dampf and Nobby Nic I have run tubeless 19 and 21psi all along, no issues with punctures or bent rims etc.

Now I've got a full sus ebike (lightweight-ish) I'm running 21 and 23psi. I'll be 100kg with gear (I hope!) - the difference in E-bike weight is minimal relatively. Most of my riding group are running low 20s and not having any issues. I even ran 28psi in my old 26"x2.2" tyres in the old days. Not sure what you guys saying "start at 26 and work up" are on about! I wouldn't contemplate running those pressures! I would say I'm "mechanically sympathetic" though - I don't just smash into stuff, I will unload the bike, lift over big rocks etc.

 

[Chris ledger]

Update on the above been riding now with 25psi and its a massive improvement over lower pressures.
Thanks for the advice.
Tbh though still not loving the maxxis tyres.
Previously found more confidence on a specialized butcher on the front of my last bike and an e wild on the rear.

 

[Chris ledger]

The e wild on the back gripped really well and was bombproof the butcher gave me loads of confidence too and also bombproof not one single puncture in 2500 miles the maxxis not so much confidence