How to run low psi w/o foldover?
#1
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Thread Starter
How to run low psi w/o foldover?
I hear about ppl running real low psi w their awesome CX tubies. They're so supple, etc. I have such tires and I do really like how they feel. I weigh 175lbs.
I have to pump mine to 30psi front / 35psi rear even on smooth trails. Any less and I start losing control rapidly, is how it feels. Risk washout on corners. Starts wallowing, esp w any out of saddle action. I think I'm tolerant of a smushy ride, too! I like a "ski" feeling in my riding.
I just read a review of tires by a guy who is about my same weight and he's talking 21-24 for FMB/Dugast/Challenge. These are my same tires.
I use a Joe Blow Sport pump. I have no idea what kind of PSI I'm really putting in coz I don't know if my gauge is accurate. I assume it is consistent so i just keep using my same pump. Also the gauge markings aren't very fine but it seems good enough that I can see what 30 and 35 are pretty good. The markings only say 20 then 40 w a few hashmarks between them.
I don't mind feeling the rim a few times per lap. When my tires smear and smush a fair bit around corners that's fine, too. What totally rules out the lower PSI for me is tire foldover on corners -- also bad washout and lack of control. That's not what we want! Handling seems to go out the window. I'm already using a kind of "ski feel" handling but with foldover the rim and tire and doing rather different things. I suppose they start getting too much smushy feel even before foldover happens. So I put in a little more air and the tire feels a lot more like a tire that I can control again. I'm willing to have a "really different experience" from mtbiking, say. But 25 seems like a nonstarter for me. Any ideas?
I have to pump mine to 30psi front / 35psi rear even on smooth trails. Any less and I start losing control rapidly, is how it feels. Risk washout on corners. Starts wallowing, esp w any out of saddle action. I think I'm tolerant of a smushy ride, too! I like a "ski" feeling in my riding.
I just read a review of tires by a guy who is about my same weight and he's talking 21-24 for FMB/Dugast/Challenge. These are my same tires.
I use a Joe Blow Sport pump. I have no idea what kind of PSI I'm really putting in coz I don't know if my gauge is accurate. I assume it is consistent so i just keep using my same pump. Also the gauge markings aren't very fine but it seems good enough that I can see what 30 and 35 are pretty good. The markings only say 20 then 40 w a few hashmarks between them.
I don't mind feeling the rim a few times per lap. When my tires smear and smush a fair bit around corners that's fine, too. What totally rules out the lower PSI for me is tire foldover on corners -- also bad washout and lack of control. That's not what we want! Handling seems to go out the window. I'm already using a kind of "ski feel" handling but with foldover the rim and tire and doing rather different things. I suppose they start getting too much smushy feel even before foldover happens. So I put in a little more air and the tire feels a lot more like a tire that I can control again. I'm willing to have a "really different experience" from mtbiking, say. But 25 seems like a nonstarter for me. Any ideas?
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Sounds like you have your pressure dialed to me. You should be bottoming out now and again and feeling them squirm. I know Cody Kaiser runs like 32psi as an elite category racer and I bet he weighs in closer to 160lbs than 175.
#3
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Like 50volt said it sounds like you know what you're doing right.
I would err on the high side and stick to the mid 30s. Too low and you risk folding the tire over or blowing it off the rim. A touch too high will just mean a little less traction in corners which you can combat with a little more practice turning.
I'm around 160 and I stick to about 35 psi on tubeless 33s.
Just the thoughts of a new cross racer though!
I would err on the high side and stick to the mid 30s. Too low and you risk folding the tire over or blowing it off the rim. A touch too high will just mean a little less traction in corners which you can combat with a little more practice turning.
I'm around 160 and I stick to about 35 psi on tubeless 33s.
Just the thoughts of a new cross racer though!
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Like 50volt said it sounds like you know what you're doing right.
I would err on the high side and stick to the mid 30s. Too low and you risk folding the tire over or blowing it off the rim. A touch too high will just mean a little less traction in corners which you can combat with a little more practice turning.
I'm around 160 and I stick to about 35 psi on tubeless 33s.
Just the thoughts of a new cross racer though!
I would err on the high side and stick to the mid 30s. Too low and you risk folding the tire over or blowing it off the rim. A touch too high will just mean a little less traction in corners which you can combat with a little more practice turning.
I'm around 160 and I stick to about 35 psi on tubeless 33s.
Just the thoughts of a new cross racer though!
My gauge must read low. On the right course, weighing in at about 190lbs, I can apparently get away with 32 psi on Maxxis clinchers with tubes.
#5
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Maybe my tolerance for squish isn't built up enough yet and I could be leaving traction at door. Or inverse of you, maybe my pump reads high. Or maybe you're just experienced enough to pick the right lines and not pinch flat. Too much to take into consideration.
#7
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I just picked up one of these:
https://www.universalcycles.com/shop...ls.php?id=8768
Thought it might be a better approach than dumping random amounts of air and going by what 'feels right' after a few practice laps. Maybe not. At least the results will be measurable now.
Got the 60psi version. Turns out my floor pump was about 10psi off! Which is huge!
Weighing in at 190lbs, 32(front)/35(rear) psi feels safe on Clement clinchers. 30 in the front felt like pinch flat territory at about 38 minutes into a race on a rough course. Didn't experiment further with the rear yet.
Should also note that the Clements measure 35mm, not the labeled 33mm.
I really want to get on some tubulars...
https://www.universalcycles.com/shop...ls.php?id=8768
Thought it might be a better approach than dumping random amounts of air and going by what 'feels right' after a few practice laps. Maybe not. At least the results will be measurable now.
Got the 60psi version. Turns out my floor pump was about 10psi off! Which is huge!
Weighing in at 190lbs, 32(front)/35(rear) psi feels safe on Clement clinchers. 30 in the front felt like pinch flat territory at about 38 minutes into a race on a rough course. Didn't experiment further with the rear yet.
Should also note that the Clements measure 35mm, not the labeled 33mm.
I really want to get on some tubulars...
Last edited by justin1138; 09-12-17 at 09:22 PM.
#10
Senior Member
I just picked up one of these:
https://www.universalcycles.com/shop...ls.php?id=8768
Thought it might be a better approach than dumping random amounts of air and going by what 'feels right' after a few practice laps. Maybe not. At least the results will be measurable now.
Got the 60psi version. Turns out my floor pump was about 10psi off! Which is huge!
Weighing in at 190lbs, 32(front)/35(rear) psi feels safe on Clement clinchers. 30 in the front felt like pinch flat territory at about 38 minutes into a race on a rough course. Didn't experiment further with the rear yet.
Should also note that the Clements measure 35mm, not the labeled 33mm.
I really want to get on some tubulars...
https://www.universalcycles.com/shop...ls.php?id=8768
Thought it might be a better approach than dumping random amounts of air and going by what 'feels right' after a few practice laps. Maybe not. At least the results will be measurable now.
Got the 60psi version. Turns out my floor pump was about 10psi off! Which is huge!
Weighing in at 190lbs, 32(front)/35(rear) psi feels safe on Clement clinchers. 30 in the front felt like pinch flat territory at about 38 minutes into a race on a rough course. Didn't experiment further with the rear yet.
Should also note that the Clements measure 35mm, not the labeled 33mm.
I really want to get on some tubulars...
#11
Senior Member
Guess I'll drop some pressure after reading everyone's posts.
Scroll down. 160 psi presta at the bottom of the list...
Scroll down. 160 psi presta at the bottom of the list...
#12
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And yeah, there's a 160psi version too.
There's a ton of other pressure gauges out there, this just happened to be the one I got. Universal is on the way home for me, and this was the unit they had at the shop (not in a wearhouse somewhere) and i wanted one NOW. Plus I've talked to people that have used this brand and they've liked them.
#13
Senior Member
I'm guessing it's waaaaaay more accurate than my floor pump.
And yeah, there's a 160psi version too.
There's a ton of other pressure gauges out there, this just happened to be the one I got. Universal is on the way home for me, and this was the unit they had at the shop (not in a wearhouse somewhere) and i wanted one NOW. Plus I've talked to people that have used this brand and they've liked them.
And yeah, there's a 160psi version too.
There's a ton of other pressure gauges out there, this just happened to be the one I got. Universal is on the way home for me, and this was the unit they had at the shop (not in a wearhouse somewhere) and i wanted one NOW. Plus I've talked to people that have used this brand and they've liked them.
I ran 40psi over the weekend at 190 lbs. It would probably have been fine at 35psi as well...I'm just chicken, and wanted to at least finish my first race lol.
#14
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Yeah...assuming I stick with this cyclocross thing I might pick up one...will be handy just for general pressure readings with normal tires.
I ran 40psi over the weekend at 190 lbs. It would probably have been fine at 35psi as well...I'm just chicken, and wanted to at least finish my first race lol.
I ran 40psi over the weekend at 190 lbs. It would probably have been fine at 35psi as well...I'm just chicken, and wanted to at least finish my first race lol.
i ran my tires at something like 60psi my first season because that's what the tires said and I didn't know any better...
#15
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Lol, nice This cyclocross thing is going to be the death of me. I've already got like 7 bikes in the garage, and this means I need like 3 more. Proper road bike, proper cyclocross bike, a tandem....
#16
Senior Member
Ran 30 psi front and back last night on some laps around the track. Felt pretty good, but seemed a little sluggish on the straight pavement sections. Need to get a proper gauge and dial it all in.
#17
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Thread Starter
I think the impt thing is to get a pump/gauge and use it. If it's decent it'll at least be consistent. Nobody's number matters but your own! Find out what you like for a given condition then just keep using that info. Doesn't matter if it's accurate. Only if it's consistent!
Still... I'm allured by the constant mentions of the Europro's riding 18-24psi and such. Of course this is determined by conditions and rider weight but still... And of course they're using tubies. Clinchers will always require more, right? Apparently suppler lets you go lower. And pricier = suppler.
Pavement and hardpack will appreciate more air, of course. It'll also appreciate filetreads or heck even roadtires. But even hardpack can have a lot of corners and offcambers so then our pressure needs to come back down again.
I have fancy highest-quality tubies. So theoretically I should be able to match those Euro's if I had the skills. I'd like to at least get a slight feel for what they're talking about.
But backing up again: maybe my pump gauge that says 30/35 is reading high and I'm actually rolling softer than that.
Also, I wonder how tire WIDTH relates to FOLDOVER. I'm thinking it's impt but am not sure. I've heard that soft mud likes narrow, so there's that. But on firmer trails I suspect 33mm will handle less PSI much better than will 30mm. My experience so far is that at 175-180 lbs I just can't ride 30mm at a pressure comfy enough to smooth out the chatter w/o foldover. Sniff. ...But I'm willing to keep trying!
I've also had issues w filetreads and race pace. Hey, they wanna slide out! I can handle corner slide just fine generally, front and rear, but so far filetreads have been a bridge too far for me at race pace. Again, I guess I'll keep trying them! Learning is fun! (Glad I bought a new can of glue!)
Still... I'm allured by the constant mentions of the Europro's riding 18-24psi and such. Of course this is determined by conditions and rider weight but still... And of course they're using tubies. Clinchers will always require more, right? Apparently suppler lets you go lower. And pricier = suppler.
Pavement and hardpack will appreciate more air, of course. It'll also appreciate filetreads or heck even roadtires. But even hardpack can have a lot of corners and offcambers so then our pressure needs to come back down again.
I have fancy highest-quality tubies. So theoretically I should be able to match those Euro's if I had the skills. I'd like to at least get a slight feel for what they're talking about.
But backing up again: maybe my pump gauge that says 30/35 is reading high and I'm actually rolling softer than that.
Also, I wonder how tire WIDTH relates to FOLDOVER. I'm thinking it's impt but am not sure. I've heard that soft mud likes narrow, so there's that. But on firmer trails I suspect 33mm will handle less PSI much better than will 30mm. My experience so far is that at 175-180 lbs I just can't ride 30mm at a pressure comfy enough to smooth out the chatter w/o foldover. Sniff. ...But I'm willing to keep trying!
I've also had issues w filetreads and race pace. Hey, they wanna slide out! I can handle corner slide just fine generally, front and rear, but so far filetreads have been a bridge too far for me at race pace. Again, I guess I'll keep trying them! Learning is fun! (Glad I bought a new can of glue!)
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its ok so far. At 25psi I've bottomed a number of times on curbs and roots and haven't burped yet. 2 wraps of gorilla tape and tubeless tires converted my wheels and made them extremely tight to mount but probably helps hold them on. When the mud arrives I'll probably try going down to 20-22psi and see if they survive
#19
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Thread Starter
So we have 175# @ 25psi tubeless, working good. Tire width? I guess we'll assume 33.
You're feeling the rim but not burping. Can we also keep foldover in the picture? I'm trying to see how that fits w PSI.
As I've said, I'm 175 and use a pump reading of 30 on my sweet 33mm tubies and I feel the rim and feel cornering sidehill smush but I don't get foldover. So far, tho, when I try 25 things get crazy and I start losing control due to excess smush. So far I only get foldover w 30mm tires at low pressure. With 33mm tires I get bad smush before I get foldover. I think...
But, again, my pump's "30psi" might be anything...
I wonder if there's some other way we can estimate what PSI we're getting. A CX pro friend just uses his thumb. He's quite a bit skinnier than me. I think he's testing to see if he can push his thumb down to the rim. Maybe we could all try that! : )
You're feeling the rim but not burping. Can we also keep foldover in the picture? I'm trying to see how that fits w PSI.
As I've said, I'm 175 and use a pump reading of 30 on my sweet 33mm tubies and I feel the rim and feel cornering sidehill smush but I don't get foldover. So far, tho, when I try 25 things get crazy and I start losing control due to excess smush. So far I only get foldover w 30mm tires at low pressure. With 33mm tires I get bad smush before I get foldover. I think...
But, again, my pump's "30psi" might be anything...
I wonder if there's some other way we can estimate what PSI we're getting. A CX pro friend just uses his thumb. He's quite a bit skinnier than me. I think he's testing to see if he can push his thumb down to the rim. Maybe we could all try that! : )
#20
Full Member
I think the impt thing is to get a pump/gauge and use it. If it's decent it'll at least be consistent. Nobody's number matters but your own! Find out what you like for a given condition then just keep using that info. Doesn't matter if it's accurate. Only if it's consistent!
Still... I'm allured by the constant mentions of the Europro's riding 18-24psi...
Still... I'm allured by the constant mentions of the Europro's riding 18-24psi...
edit: oh... and loose some weight if you want lower pressure without the fold over. or don't turn?
Last edited by justin1138; 09-14-17 at 04:40 PM.
#21
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So we have 175# @ 25psi tubeless, working good. Tire width? I guess we'll assume 33.
You're feeling the rim but not burping. Can we also keep foldover in the picture? I'm trying to see how that fits w PSI.
As I've said, I'm 175 and use a pump reading of 30 on my sweet 33mm tubies and I feel the rim and feel cornering sidehill smush but I don't get foldover. So far, tho, when I try 25 things get crazy and I start losing control due to excess smush. So far I only get foldover w 30mm tires at low pressure. With 33mm tires I get bad smush before I get foldover. I think...
But, again, my pump's "30psi" might be anything...
I wonder if there's some other way we can estimate what PSI we're getting. A CX pro friend just uses his thumb. He's quite a bit skinnier than me. I think he's testing to see if he can push his thumb down to the rim. Maybe we could all try that! : )
You're feeling the rim but not burping. Can we also keep foldover in the picture? I'm trying to see how that fits w PSI.
As I've said, I'm 175 and use a pump reading of 30 on my sweet 33mm tubies and I feel the rim and feel cornering sidehill smush but I don't get foldover. So far, tho, when I try 25 things get crazy and I start losing control due to excess smush. So far I only get foldover w 30mm tires at low pressure. With 33mm tires I get bad smush before I get foldover. I think...
But, again, my pump's "30psi" might be anything...
I wonder if there's some other way we can estimate what PSI we're getting. A CX pro friend just uses his thumb. He's quite a bit skinnier than me. I think he's testing to see if he can push his thumb down to the rim. Maybe we could all try that! : )
#22
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Thread Starter
Here's another factor that may or may not be very relevant: RIM WIDTH.
Velocity makes the Major Tom wheelset for CX and it has a WIDER rim that they say is good for CX. I hadn't heard about wider rims for CX before. From what I read they're talking about better glueing. ...But better gluing relates to stability as well as plain old security so the tire doesn't roll.
Conveniently, a friend gave me his old Major Tom wheelset so I could give it a try to see if it helps my wonderful Dugast 30's stop folding over at my desired PSI. Or if it at least helps me run a few more lbs softer than I can now on a narrower rim.
Oh, another thing I could probably do better with: gluing tight all the way out to the edge of the rim. Sometimes when I torque my tires back and forth laterally they open up a bit of a gap at the rim. That can't help w foldover, right? Apparently this is why rim bed shape is a thing. Whew. I wonder if there are fixes after a tire is mounted -- like flowing in more glue along the gap and, um, inflating or deflating to whatever setup squishes the tire outward the most then let it cure. ...Might grab the outer edges of the rim that way?
Velocity makes the Major Tom wheelset for CX and it has a WIDER rim that they say is good for CX. I hadn't heard about wider rims for CX before. From what I read they're talking about better glueing. ...But better gluing relates to stability as well as plain old security so the tire doesn't roll.
Conveniently, a friend gave me his old Major Tom wheelset so I could give it a try to see if it helps my wonderful Dugast 30's stop folding over at my desired PSI. Or if it at least helps me run a few more lbs softer than I can now on a narrower rim.
Oh, another thing I could probably do better with: gluing tight all the way out to the edge of the rim. Sometimes when I torque my tires back and forth laterally they open up a bit of a gap at the rim. That can't help w foldover, right? Apparently this is why rim bed shape is a thing. Whew. I wonder if there are fixes after a tire is mounted -- like flowing in more glue along the gap and, um, inflating or deflating to whatever setup squishes the tire outward the most then let it cure. ...Might grab the outer edges of the rim that way?
Last edited by JeffOYB; 09-15-17 at 11:01 AM.
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I'll add a third recommendation for a Meiser gauge. They're guaranteed to be within +-2% and will really help you tweak your setup. Best $15 I ever spent on CX and mtb and never needs batteries. FWIW I'm the same 190 lbs and run Clement MXP clinchers at 32f/45r on A23 rims. That's as low as I'm comfortable without risking rim damage. If the course is firm with little sand I sometimes go up 2-3psi higher from there.
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Just some random additions to the conversation:
I'm about 165lbs, my tubular race setup is on a Major Tom rim (23mm width I think?), with 33mm Challenge Baby Limus tires.
For regular trail riding and training rides, I typically run these around 35psi on them and have zero fold-over in turns, never feel the rim on bumps, etc. They're still pretty soft and floaty at that pressure, but firm enough that I also don't feel like they're an anchor on pavement.
For racing I usually do a pre-ride at 25psi and adjust for conditions from there. Last weekend's race I was running them at 25psi, as the course was very dry and relatively smooth. I tried to go lower (like 22psi) but could feel the rear folding over when I accelerated hard out of tight corners, and the front felt a little mushy on fast downhill sweepers, so I went back up to 25psi. This was my first race in 2 years, so maybe just need to get used to the feeling again.
In the past I've raced as low as 20psi on some really muddy tracks.
I also use a Joe Blow floorpump with a gauge, and this year bought an analog gauge from Amazon that has more defined numbers. The Joe Blow gauge is within 1-2 psi of the other, but the gradation is so small on the floor pump that it makes it hard to really dial in closer than 2-3psi. With the hand gauge, I can get down to 1psi difference pretty easy.
I'm about 165lbs, my tubular race setup is on a Major Tom rim (23mm width I think?), with 33mm Challenge Baby Limus tires.
For regular trail riding and training rides, I typically run these around 35psi on them and have zero fold-over in turns, never feel the rim on bumps, etc. They're still pretty soft and floaty at that pressure, but firm enough that I also don't feel like they're an anchor on pavement.
For racing I usually do a pre-ride at 25psi and adjust for conditions from there. Last weekend's race I was running them at 25psi, as the course was very dry and relatively smooth. I tried to go lower (like 22psi) but could feel the rear folding over when I accelerated hard out of tight corners, and the front felt a little mushy on fast downhill sweepers, so I went back up to 25psi. This was my first race in 2 years, so maybe just need to get used to the feeling again.
In the past I've raced as low as 20psi on some really muddy tracks.
I also use a Joe Blow floorpump with a gauge, and this year bought an analog gauge from Amazon that has more defined numbers. The Joe Blow gauge is within 1-2 psi of the other, but the gradation is so small on the floor pump that it makes it hard to really dial in closer than 2-3psi. With the hand gauge, I can get down to 1psi difference pretty easy.
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I'll add a third recommendation for a Meiser gauge. They're guaranteed to be within +-2% and will really help you tweak your setup. Best $15 I ever spent on CX and mtb and never needs batteries. FWIW I'm the same 190 lbs and run Clement MXP clinchers at 32f/45r on A23 rims. That's as low as I'm comfortable without risking rim damage. If the course is firm with little sand I sometimes go up 2-3psi higher from there.