Schwalbe Ultremo DD 700x25c tire pressure?

Xfimpg

Hi Everyone

Is anyone aware of any recommended psi discrepancies with the Ultremo DD 700x25?

This Schwalbe website states 85-130 psi (6,0-9,0 Bar).
http://www.schwalbe.com/gbl/en/produkte ... rodukt=197

This other Schwalbe website states 85-115 psi (6,0-8,0 Bar).
http://www.schwalbetires.com/bike_tires ... ultremo_dd

Huh??

My tires read 85-115 psi (6,0-8,0 Bar) HOWEVER I can't ride downhill faster than 40Kph (at 115psi) because my rear feels very squirrely, the same feeling you get when you have a leek and are losing pressure. It's very very unnerving!

Does anyone have any insight on this? Btw, I built my roadie this winter and all is brand new, nothing lose in the rear wheel.

Thanks in advance
Mike

Barteos

The pressure depends on your weight and road surface.
http://www.dorkypantsr.us/bike-tire-pre ... lator.html

huuregeil

Unless you or your bike are very heavy, 115 is *way* too much pressure for those tyres! I weigh in at 70kg and am running those at 80/85 f/r.

nferrar

How heavy are you? I run 25 DD's on one bike @ 100psi and the bike's fine (up to about 50mph anyhow, not sure I've gone faster on that bike). I'm 14st btw...

keef66

I'm 10st 10lbs and run 25mm Conti 4 Seasons at 75-80 front and 85-90 rear. No squirrels for me!

bigpikle

76kg and run mine at 95psi front and rear. Did me fine across the Pyrenees including down the Tourmalet at >70km/hr... Never have any issues even on the poor UK surfaces.

team47b

Useful info on tyre sizes, scroll down to the foot of the page for a tyre pressure to total weight chart, simple explanation, I thought...

http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3802

Xfimpg

Thanks guys for the feedback.

I weigh 198 pounds... not sure how many stones that is.

I really dont know where that squirrliness is coming from, especially at such a low speed.
The rear wheel is triple-laced, solid and brand new.

Xfimpg

I do wonder though about the psi discrepancy on Schwalbe's website. I have noticed that at 115psi the tire is softer than other tires i have had at the same psi.

Hhalo

I run these tyres on Shimano R80 rims. Today on a short climb while riding out of the saddle, I felt something rubbing on the rear brakes. When stopping I could see the tyre bulging from the side of the rim and the inner tube just exploded. I only had about 110psi in the tube, and am not too heavy (72 kg). Either the tyre was not seated correctly in the rim, or I suspect the sidewall on the Schwalbe DD is a bit weak. This could explain why Schwalbe have down rated the running pressure on the Tyre. In the future, I think I will not pump it pass 95psi.

Xfimpg

Hhalo wrote:

I run these tyres on Shimano R80 rims. Today on a short climb while riding out of the saddle, I felt something rubbing on the rear brakes. When stopping I could see the tyre bulging from the side of the rim and the inner tube just exploded. I only had about 110psi in the tube, and am not too heavy (72 kg). Either the tyre was not seated correctly in the rim, or I suspect the sidewall on the Schwalbe DD is a bit weak. This could explain why Schwalbe have down rated the running pressure on the Tyre. In the future, I think I will not pump it pass 95psi.

Thanks for the feedback.
I did call Schwalbe NA and they had no answer for the psi discrepancy or the rear wheel squirrling.
After insisting a few times, they said they would contact the head office.
For some reason I don't think this is going to happen.
The feel of these tires is great, but unfortunately they don't instill confidence and the problems i've reported don't help either.
I'm going to junk them and move on.

huuregeil

Before you junk the tyres, have you tried running them at a sensible pressure? Also, have you checked out other sources of handling wierdness (play in the wheel bearing; or it could simply be a lack of stiffness in the new frame you've got - try resting a knee against the top tube when descending to "stiffen" the frame up). These tyres, I think, are great and I have a great deal of confidence in them, but they aren't the most supple so you do need to get the right pressure (i.e. a lower pressure) in them.

desweller

The max pressure rating on the tyre sidewall is not a recommendation for optimal pressure. The grip from the tyre is dependant on the compliance of the tyre; if you run them too high you'll lose grip and make it difficult for the tyre to cope with unevenness in the road surface.

Xfimpg

Thanks guys, I haven't junked them yet, and i'll try to answer you both.

The rear tire feels squishy, like the rear end is moving side to side. It doesn't jump up or around like a tire that is simply too hard.
It feels like a tire that doesn't have enough pressure and not the opposite, which is why I'm going to try the pressure range as indicated on the other Schwalbe website.

The frame I have this on is a 2011 Specialized Roubaix Pro, brand new and very stiff. When I climb, the bb area doesn't budge; it's pretty impressive. :-)
I did verify the rear wheel and there is no give to it. It's 3x-laced on side and 2x on the other, so I don't see where there could be any give there.

Xfimpg

By "pressure range", I mean that i'm running the tire at 115psi now, so I will increase it to 130psi and see if the rear reacts differently.

nferrar

Personally I wouldn't run it at 130psi even if it's rated that high. Not sure what's causing the squirrelly sensation you're experiencing, have you tried running the rear with a different tyre just to make sure it is the tyre and not something else on the bike? I find Conti GP4seasons similar grip level to an Ultremo if you wanted an alternative (although personally I prefer Ultremos).

FransJacques

Hhalo's issue is almost certainly bad installation - sometimes part of the tube can sneak under the bead when seating the tyre. Pump it up to 10-15 psi then work your way around the wheel and bend the tyre with some force side to side to it help seat.

Xfimpg, the advice above is excellent - you can tell it's from peeps with lots of experience. Most people do start high (115-120) and learn tyres behave much better at 85-95 psi for most weights, esp on crap, wet roads. On crap, wet roads you need to give the tyre latitude to deform around obstacles that might puncture it and to adhere to the road surface. Your contact patch is your friend.

Go out and have fun experimenting: start at 80psi and work up from there. Even if you just have a small hand pump on you, do 5 -10 pump strokes per tyre then ride for 5 more KMs then stop and repeat. See what you like, but don't rely on your very first impressions: what works on bumpy roads feel different when on a billiard table smooth recently laid asfault climb . People run the rear a bit harder to prevent it from bottoming out and the front less to a) give your wrists and hands some cushion, and b) b/c wiping our your front wheel is more painful and less recoverable than sliding out the rear. Although both are not fun.

Xfimpg

FransJacques wrote:

Hhalo's issue is almost certainly bad installation - sometimes part of the tube can sneak under the bead when seating the tyre. Pump it up to 10-15 psi then work your way around the wheel and bend the tyre with some force side to side to it help seat.

Xfimpg, the advice above is excellent - you can tell it's from peeps with lots of experience. Most people do start high (115-120) and learn tyres behave much better at 85-95 psi for most weights, esp on crap, wet roads. On crap, wet roads you need to give the tyre latitude to deform around obstacles that might puncture it and to adhere to the road surface. Your contact patch is your friend.

Go out and have fun experimenting: start at 80psi and work up from there. Even if you just have a small hand pump on you, do 5 -10 pump strokes per tyre then ride for 5 more KMs then stop and repeat. See what you like, but don't rely on your very first impressions: what works on bumpy roads feel different when on a billiard table smooth recently laid asfault climb . People run the rear a bit harder to prevent it from bottoming out and the front less to a) give your wrists and hands some cushion, and b) b/c wiping our your front wheel is more painful and less recoverable than sliding out the rear. Although both are not fun.

Thanks guys for all the advice.
Question for you all: is it possible that a wheel may have more give on one side than other if it's laced 2x on one side and 3x on the other? Could this be the source of the squirrely problem?

rpd_steve

The lacing pattern does not affect the lateral stifness - it affects the radial and hoop stifness, i.e. the stifness when torque is applied. In fact the less cross it is the stiffer it is laterally for a given spoke tension.

I very much doubt this is your issue. Sounds like badly seated tyre to me- quite common. Some tyres are a real bugger!

Xfimpg

RPD Steve wrote:

The lacing pattern does not affect the lateral stifness - it affects the radial and hoop stifness, i.e. the stifness when torque is applied. In fact the less cross it is the stiffer it is laterally for a given spoke tension.

I very much doubt this is your issue. Sounds like badly seated tyre to me- quite common. Some tyres are a real bugger!

In a way I am hoping it is a badly-seated tire! :oops:

I've read about tire and rim incompatibilty; what would be the symptoms?

FransJacques

http://www.cyclingnews.com/features/pho ... aix/217563

Before you think 130psi is the *only* way to go please have a look at the Roubaix pressures. Obviously they are at the other end of the spectrum (to my knowledge the spectrum starts around 24-26 psi for MTB tubs to ~200 psi for track tubs. B/c of their construction, clinchers fall well within this.) Roubaix tyres run up to 30mm so don't try 4 bar (58psi) with your 19mm flimsy Veloflex Records but it underlines how the pros love to experiment with tuning pressure to condition.

Xfimpg

So I moved the Ultremo DD to a different wheelset (same brand), this one is laced on 2x in the rear but for some reason the spokes are tighter than the 3x wheelset. ??
Problem solved, no more bouncing around in the rear.
So go figure. A 2x rear that is tighter than a 3x. All this time I thought 3x were for Clydesdales.

nferrar

Probably more to do with the quality of the wheel build than the lacing pattern I'd think

Xfimpg

nferrar wrote:

Probably more to do with the quality of the wheel build than the lacing pattern I'd think

Good point. The blades do seem pretty thin. I'm considering bringing the wheel to an LBS and having them replace the blades with something more sturdy.

rpd_steve

There is no reason that the spokes cant have the tension increased. Those 'flimsy' looking spokes will take way over 500kg each. It does not matter what spokes are in there so much (so long as they are stainless steel) provided they are tensioned correctly and evenly. About the 100kg on the front and about 90 RNDS and 120 RDS depending on the dish required.

Xfimpg

RPD Steve wrote:

There is no reason that the spokes cant have the tension increased. Those 'flimsy' looking spokes will take way over 500kg each. It does not matter what spokes are in there so much (so long as they are stainless steel) provided they are tensioned correctly and evenly. About the 100kg on the front and about 90 RNDS and 120 RDS depending on the dish required.

Thanks for the tip, i'll get them to do that first.

And thanks to all of you for your feedback and input.