Cancelling out tyre...
 

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[Closed] Cancelling out tyre feedback...

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I'm using 66tpi tyres for the first time (I've been 3yrs on schwalbe 127tpi) and swear I can feel and impact of their "bounce" through the bike.

What to I need to do to mechanically to cancel that out, more or less pressure in them, or adjustment to rebound, air, or compression in the shock?


 
Posted : 09/12/2014 7:08 pm
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Just get someone else to "put different tyres on"* and it'll be as if nothing happened.

* ie get them to take it away and bring it back 1/2 hour later withthe tyres moved on the rims. You're imagining it.


 
Posted : 09/12/2014 7:39 pm
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You need some of that special new 'Enduro' tyre air.


 
Posted : 09/12/2014 7:41 pm
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Imagining it? Hmmm. It is a very different bike my old one, and I'm not unhappy at all but have this nagging "plastic" thought going through my head when I "feel" the tyres rebounding.


 
Posted : 09/12/2014 7:45 pm
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You have a very refined sense of perception.

Life's too short to use rubbish tyres, just get the ones you want.


 
Posted : 09/12/2014 7:48 pm
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What bike, what tyres what psi? Some OEM tyres do have a noticeable difference to non OEM plus if it's a lot different tyre construction ie less flexible side wall then they will feel different obviously. Are we talking MTB or road.....because it sounds like you're describing a fat bike 😆


 
Posted : 09/12/2014 7:49 pm
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Mtb, anthem 29er rocket ron "performance" - the new dual compound version. Prior bike was a ASR5 with Nobby Nic pace star. So there is a compound & suspension system difference

Chakaping I did buy these deliberately.


 
Posted : 09/12/2014 7:53 pm
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Oh right, sorry, ignore my previous comment, terribly out of line, my apologies.

You need "XC" tyre air for that setup.

😉


 
Posted : 09/12/2014 8:00 pm
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Don't forget if your suspensions not bedded in yet as well you will get some more sensation from the trail and tyres that you've not had.......bit like the difference I find between riding air forks and coil, the air are never as smooth feeling on harder surfaces.
The smaller lower tread blocks of the new tire set up will also give a firmer ride as the blocks won't move about so much on the carcass...
Switch off from it ride it like you stole it and crash it to get over the initial over analysis of the differences..... Two totally different set ups and bikes so you will not get the same feeling until you are used to it...
That's my theory anyhow. 😆


 
Posted : 09/12/2014 8:45 pm
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I doubt I'd notice the difference you're feeling but the Performance/ORC Schwalbes I've used were no damn good at all. So this'd result in an epic skidding session followed by a credit card bill


 
Posted : 09/12/2014 8:47 pm
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Suggsey a fair point I am on ride 4 with this bike albeit ride 2 was a weekend at Afan. I take your point re the tyre difference Fwiw even in 26 I never ran a ron on the rear. Note also have another current thread re anthem shock pressure and I may be running my shock a little low in pressure so this might not be helping me.

north wind, I rode the stock ralphs performance in Afan, as mentioned they are the newer DC compound and so impressed was I at thier grip on the wet trails I didn't hesitate to pay half the price of a pacestar for a Ron, also notable is the thicker sidewall as standard meaning more puncture protection hopefully and easier tubeless.


 
Posted : 09/12/2014 8:52 pm
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Imagining it? Hmmm. It is a very different bike my old one, and I'm not unhappy at all but have this nagging "plastic" thought going through my head when I "feel" the tyres rebounding.

Your not imagining it, it's something I noticed when going from standard 60/70a to super tacky 42a (exactly the same tyres/construction), compound has a definite damping effect.

Don't know what you can do about, less air pressure should equal less rebound.

The difference is more pronounced than the pound or so I've saved on my new wheelset.


 
Posted : 09/12/2014 9:06 pm
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They're different tyres, you'll be faffing forever and they'll never feel the same - just buy the tyres you want or just get on with it


 
Posted : 09/12/2014 9:10 pm
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it's something I noticed when going from standard 60/70a to super tacky 42a

That's a difference in rubber compound.
OP it talking about a difference in TPI. (Threads Per Inch) Which is how the carcass is made.

Closer to the difference you'd feel between a dual ply and a single ply but not as extreme.


 
Posted : 09/12/2014 9:13 pm
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What to I need to do to mechanically to cancel that out, more or less pressure in them, or adjustment to rebound, air, or compression in the shock?

You need to read a basic guide on how suspension works, then you'll know how to adjust it for your own tastes.


 
Posted : 09/12/2014 9:17 pm
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OP it talking about a difference in TPI. (Threads Per Inch) Which is how the carcass is made.

He's also gone from pacestar to dual compound.


 
Posted : 09/12/2014 9:20 pm
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are you Hora?


 
Posted : 09/12/2014 9:21 pm
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Are you all tyre testers??


 
Posted : 09/12/2014 9:24 pm
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Well I know that Rusty and having just reviewed Anthem setup I need to increase my pressure. The low pressure - and I er forgot to lower my rebound - lot of rebound damping will make it harsh over small bumps. So that's step one.

Singlespeedstu - note above that actually the compound has changed. I believe the DC compound is 70a/60. I think pace star is less than that.


 
Posted : 09/12/2014 9:25 pm
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Maxxis used to make 40a tyres that where known as slow reazay or slow rebound, its a property of the tyre its not imagination.


 
Posted : 09/12/2014 9:29 pm
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But do we know rocket ron performance DC is "bouncy"? And if it is, I refer you to my op - how to cancel it out?


 
Posted : 09/12/2014 9:31 pm
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good god man just ride the bloody bike


 
Posted : 09/12/2014 9:43 pm
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If the compound is softer it should feel less "bouncy"
If the TPI is higher it should also feel less "bouncy"

You should be able to get away with running a slightly lower pressure with a lower TPI as it should be a tad stiffer.


 
Posted : 09/12/2014 9:45 pm
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Kryton57 - Member

Well I know that Rusty

I need to increase my pressure. The low pressure - and I er forgot to lower my rebound - lot of rebound damping will make it harsh over small bumps. So that's step one.

🙂

You should be able to get away with running a slightly lower pressure with a lower TPI as it should be a tad stiffer.

I can't see how it could massively affect the required spring rate.
Damping, yes. And a stiffer tyre may give the effect of slightly more preload, but the damping would logically be the parameter that would be most affected.


 
Posted : 09/12/2014 9:50 pm
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Ok. So harder compound plus lower tpi than I'm used to is what im feeling. I was running it at 28psi I'll try a bit lower.

I should have said earlier it was most notable when riding along a packed gritstone / gravel type double track. I don't think my shock pressure has helped, it was probably slowing packing on the high frequency bumps. Fwiw I never notice this in Afan running the shock at 165psi on the Ralph's granted they are a different tread pattern. I'll try the shock first and see how I go.


 
Posted : 09/12/2014 9:53 pm
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Rusty.
I'm talking about tyre pressure not shock pressure.


 
Posted : 09/12/2014 9:53 pm
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.


 
Posted : 09/12/2014 9:55 pm
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singlespeedstu - Member

Rusty.
I'm talking about tyre pressure not shock pressure.

Ah, gotcha.
🙂
You could make a less supple tyre feel a bit more so by decreasing the pressure
You'd still be liable for more pinch flats though.


 
Posted : 09/12/2014 9:57 pm
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TBF OP if you don't get on with the tyres for whatever reason just change them to something you know and like before you start changing the suss setup on your new and unfamiliar bike.
That way even if it's just in your head the problem will be solved. 🙂


 
Posted : 09/12/2014 10:01 pm
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Hmm I notice some differences in carcass I found Maxxis EXO much stiffer than Scwalbe for example. But tread and compound make a bigger difference.


 
Posted : 09/12/2014 10:06 pm
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Sure fair point. But I was slowly reducing the pressure as I was learning the bike, and trying to get full travel. Fwiw it might only be that I need to wind back the rebound which I should have done as I lowered the pressures, but didn't. I'll try that, then if that doesn't work I'll increase the pressure again back to where I was happy. If no joy it'll then be the tyre and I'll change it.


 
Posted : 09/12/2014 10:09 pm
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Kryton57 - Member
I should have said earlier it was most notable when riding along a packed gritstone / gravel type double track. I don't think my shock pressure has helped, it was probably slowing packing on the high frequency bumps.

I don't really understand.
Just explain again what feels wrong.

Your shock pressure should be fine if it's set for your weight and within the recommended sag limits.
Check this first so it's not an issue.

Try your tyres at the pressure you used to use on your old bike - as long as they're not outrageous you can then think about the damping.

What damping adjustment have you got?
How does it feel at the mo?
Which bits are too bouncy and when?


 
Posted : 09/12/2014 10:18 pm
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They are at the same pressure as before, but I'm coming from 26" pace star Nic to 29" DC Ron.

Shock is a fox CTD evolution 2014 (the one where CTD works) and I was running it in descend / open. Therefore it has CTD and rebound only.

The rear wheel felt it was a bit lively on small gravelly stones, and seems to ping back at me on roots. Normally I would have put this down to the shock but is was running about 30% sag and with some hefty rebound damping. I can "hear" the difference in the tyres as well, hence I'm convinced thats what it is.


 
Posted : 10/12/2014 5:44 am
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I had the same issue when I swapped shorts for ones with a slightly thicker chamois. I spent weeks altering tyre pressures and trying different thicknesses of baggies in an effort to normalise the rebound effect. I even tried several different saddles. Eventually I simply wore my old shorts instead, which solved the problem instantly.

Have you tried different shorts?


 
Posted : 10/12/2014 8:59 am
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Put a set of matching durometer rubber insoles in your shoes to cancel out the resonance amplitude wavelength.


 
Posted : 10/12/2014 9:24 am
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Maxxis used to make 40a tyres that where known as slow reazay or slow rebound, its a property of the tyre its not imagination.
Schwable had an infomercial (or was it a magazineinterview with Schwable?) where they basicly debunked a lot of that stuff. Hysteresis, coeficients of friction, hardness aren't nececeraly dependant on each other, you can make grippy tyres that don't wear (Conti black chilli being a good marketed example), or soft tyres that do or dont rebound quickly, it was all to do with the formulation of the rubber and the ammounts of silica and carbon in the mix as well as the casing.


 
Posted : 10/12/2014 10:20 am

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