Sherman tire pressure equivalent to other wheels?

[Daley1]

Sherman tyre pressure equivalent to other wheels?

Unequivocally NO!

[Planemo]

4 hours ago, Rich Sam said:

ewheels has told me they recommend at least 40 psi, any lower, and you risk rim damage.

Theres been several riders that have busted their rims at 40psi (and more) so I can't agree with that.

Look, the rims are just shit. Each and every Sherman rider needs to judge for themselves what sort of riding they do and run pressure accordingly because just telling people to run high pressure isnt the answer. You're knackered if you run too low (due to tyre bottoming) and you're knackered if you run too high (no yield in the tyre so the rim takes all the stress).

A stock knobbly at 40+ psi is bloody rock hard. Lord knows how much stress thats shoving through the rim, which is why I still run 23psi and no issues yet with bottoming out so I will stick with it.

Someone who likes going up kerbs etc wont have any option and will have to run more pressure but dont think for a minute that doing so wont bring its own problems. A rock hard tyre + rider + Sherman will transfer huge stresses onto the rim.

 

[bracky72]

Riding at 40 psi is insane unless you weight 300 lbs.  Any little bump will send you flying. It would be like pumping your car tires up to 40-50 psi. To hard!  Poor performance. 

[Rich Sam]

6 hours ago, Planemo said:

Theres been several riders that have busted their rims at 40psi (and more) so I can't agree with that.

Look, the rims are just shit. Each and every Sherman rider needs to judge for themselves what sort of riding they do and run pressure accordingly because just telling people to run high pressure isnt the answer. You're knackered if you run too low (due to tyre bottoming) and you're knackered if you run too high (no yield in the tyre so the rim takes all the stress).

A stock knobbly at 40+ psi is bloody rock hard. Lord knows how much stress thats shoving through the rim, which is why I still run 23psi and no issues yet with bottoming out so I will stick with it.

Someone who likes going up kerbs etc wont have any option and will have to run more pressure but dont think for a minute that doing so wont bring its own problems. A rock hard tyre + rider + Sherman will transfer huge stresses onto the rim.

 

There is a difference between someone saying they damaged it at 40, and people actually filling to 40 with known good pressure reading right before the hit.  I run a TPMS system on my sherman and I know what pressure it is at all times. 

I don't bump curbs on sherman, I will occasionally drop off a small curb.  Its potholes that will get you.  Like I mentioned in my post do the 2x4 test with a high speed camera.  If the 2x4 eats halfway into the tire at 10-15 than a pothole will do you in at 30 Just sayin.

[Rawnei]

Stating which tire you have is of importance, I can't imagine riding the Kenda 262 (Knobby Tire) at 40+ PSI, like riding a trampoline?

[Rich Sam]

5 hours ago, bracky72 said:

Riding at 40 psi is insane unless you weight 300 lbs.  Any little bump will send you flying. It would be like pumping your car tires up to 40-50 psi. To hard!  Poor performance. 

I have ridden 40+ psi at rider weight of 230 lbs since day one.  Believe me it is easily rideable.  With the sherman is there such a thing as a light rider?  The wheel itself is 80 lbs.

[Rich Sam]

22 minutes ago, Rawnei said:

Stating which tire you have is of importance, I can't imagine riding the Kenda 262 (Knobby Tire) at 40+ PSI, like riding a trampoline?

Yup I have stock Kenda.  If given a choice between taco-ing the rim and riding out an occasional bounce.  I will take the bounce any day.  I hit a hidden HUGE pothole the other night at 30 mph... at 40 psi I still have a micro deformity that is barely noticeable if I rotate the tire and really look for it.  If I was less than 40 I'm sure I would have taco-ed my rim.

[Rawnei]

5 hours ago, Rich Sam said:

Yup I have stock Kenda.  If given a choice between taco-ing the rim and riding out an occasional bounce.  I will take the bounce any day.  I hit a hidden HUGE pothole the other night at 30 mph... at 40 psi I still have a micro deformity that is barely noticeable if I rotate the tire and really look for it.  If I was less than 40 I'm sure I would have taco-ed my rim.

Are you hitting pot-holes by mistake or is it anticipated? If you can anticipate it you can bounce it.

I ride the Kenda 262 on both my Sherman (30 PSI) and the MSP (28 PSI), never got a dent from a pothole, the MSP I ride gnarly off-road and in skateparks doing jumps and high drops, no deformities to my rims, I'm around ~95kg (~209lbs) all geared up. Most important thing I would say is to not to hit a hard edge head-on brute force no matter what tire or PSI you have, bunny jumping (if you pads that allow it) or bonking tall edges is a must use technique.

Other rides I know ride various tires at very low PSI (18-24) and no issues there either, I only know two cases of damaged rims one was from a rider hitting a huge pothole by mistake falling off and getting a dent the other was from a rider jumping and hitting a rock at the landing.

[Planemo]

6 hours ago, Rich Sam said:

There is a difference between someone saying they damaged it at 40, and people actually filling to 40 with known good pressure reading right before the hit.  I run a TPMS system on my sherman and I know what pressure it is at all times. 

Lets not get into 38psi Vs 42psi. We are talking the 'higher end'of pressures. And btw I gave up on TPMS' because of how inaccurate they were.

6 hours ago, Rich Sam said:

Like I mentioned in my post do the 2x4 test with a high speed camera.  If the 2x4 eats halfway into the tire at 10-15 than a pothole will do you in at 30 Just sayin.

I dont and have never run into potholes or 2x4's at 10 to 15 because I would see them.

I see everything. And if by rare chance I dont (because I am going to fast or because its too dark) then thats on me. And if I knacker my rim because the tyre is too soft OR too hard its on me. I known the limitations of the current Sherman rim.

I shouldn't have to worry about busting my rim in either case, but it is what it is. I would rather run a lower pressure for comfort and handling than run 40+ in the hope that one day it will save my ass (or it might not) in the rare circumstance that I miss a pothole or a lump of 4x2. In any event, a Sherman hitting something nasty at any pressure is likely to bust the rim.

I will stick with 23psi thanks.

[Rich Sam]

1 hour ago, Rawnei said:

Are you hitting pot-holes by mistake or is it anticipated? If you can anticipate it you can bounce it.

I ride the Kenda 262 on both my Sherman (30 PSI) and the MSP (28 PSI), never got a dent from a pothole, the MSP I ride gnarly off-road and in skateparks doing jumps and high drops, no deformities to my rims, I'm around ~95kg (~209lbs) all geared up. Most important thing I would say is to not to hit a hard edge head-on brute force no matter what tire or PSI you have, bunny jumping (if you pads that allow it) or bonking tall edges is a must use technique.

Other rides I know ride various tires at very low PSI (18-24) and no issues there either, I only know two cases of damaged rims one was from a rider hitting a huge pothole by mistake falling off and getting a dent the other was from a rider jumping and hitting a rock at the landing.

Mistake, I do night rides with a fast group.  I usually see potholes... sometimes one sneaks up on me.

[Rich Sam]

29 minutes ago, Planemo said:

Lets not get into 38psi Vs 42psi. We are talking the 'higher end'of pressures. And btw I gave up on TPMS' because of how inaccurate they were.

I dont and have never run into potholes or 2x4's at 10 to 15 because I would see them.

I see everything. And if by rare chance I dont (because I am going to fast or because its too dark) then thats on me. And if I knacker my rim because the tyre is too soft OR too hard its on me. I known the limitations of the current Sherman rim.

I shouldn't have to worry about busting my rim in either case, but it is what it is. I would rather run a lower pressure for comfort and handling than run 40+ in the hope that one day it will save my ass (or it might not) in the rare circumstance that I miss a pothole or a lump of 4x2. In any event, a Sherman hitting something nasty at any pressure is likely to bust the rim.

I will stick with 23psi thanks.

No one wants to force anyone to do something they don't want to.  If you want to ride low that's on you.  I'm just sharing what lots of sherman riders do, ones that ride in the city where big potholes are a thing.  Had a rider out here trash his sherman first week of ownership running at @ 20 PSI, impressive the damage that pothole did.  This weighed half my body weight, I'm sure.

Some TPMS systems are very accurate, Both my sensors are within .2 psi difference of each other.  Not bat at all, which is within tolerance of just removing them as fast as I can.

[EUC AZ]

I have broken 2 rims on potholes at 40-45 psi.  I never ride below 40psi cause I'm scared for my rims 😨.   low psi feels like riding in mud.  you lose a a bunch of maneuverability.  

Edited August 3, 2021 by EUC AZ

[EMA]

psi is related to tire (compound + size) and global weight ( rider + wheel )

• the same tire on different wheels needs adjustments, a 25kg msp is way different from a 35kg sherman
• a thin soft tire like cyt 5102 and cst 1488 use a relatively high pressure compared to motorcycle tire
• cst 1488 at 35psi is "normal" , a michelin or a continental a 35 psi is really stiff
• smaller the size, higher the pressure

don't forget to evaluate riding style, hitting something at speed with "low" pressure it's 100% a damaged rim

[RhoadsNRoses82]

i was always riding my V11 around 27 PSI, and i'm 195lbs. I tried pumping it up to 38 once and the difference in ride was so massive i quickly dropped it back to 30. At 38 it felt like the wheel was moving way too much beneath my feet. however at my weight, i think 27-30 might be too little, cuz i did slightly bend a small part of the rim, on one side. even without any serious offroading...just a few small curb drops.