Suspension question on rebound

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Miztaziggy
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Suspension question on rebound

Post by Miztaziggy »

Been reading this:
https://lifeatlean.com/motorcycle-tyre-wear-guide/

Specifically the bit about rebound being too fast or slow and causing the bobble on leading or trailing edge of the tread mark.

My tyre has a big bobble of rubber on the front edge of the horizontal tread lines, apparently meaning the rebound is too 'slow'.

What does 'slow' mean? Does that mean rebound is too hard or soft? i.e. turning the adjuster clockwise stiffens the rebound, makes it harder. Turning it anticlockwise makes the rebound softer and more bouncy.

Does rebound being too slow mean it's too far clockwise or anticlockwise on the adjuster?


One last bit of information: I found that when I pressed down the rear end near the end of the day, it returned up quite slowly. I turned the adjuster anticlockwise and it got better, and felt better.
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tony.mon
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Re: Suspension question on rebound

Post by tony.mon »

Slow means it takes too long to rebound. So if it's too hard, you need to soften it a bit.
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E.Marquez
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Re: Suspension question on rebound

Post by E.Marquez »

If you have not re sprung for your weight, before you get in to settings, check to see if your just bottom the suspension and thats why it feels too "stiff"
Take a plastic zip tie and place around the fork stanchion. Tighten it tight, and slide to the bottom, the go ride a "normal" rout See where that zip tie is... if it is all the way UP.. the too hard or "stiff" ((There is a joke there someplace)) you are feeling is likely you running out of suspension travel.
You will just chase your tail trying to adjust settings if your not sprung for your weight.
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popkat
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Re: Suspension question on rebound

Post by popkat »

Slow is hard, fast is soft. think of the adjuster as a screw, turn it in for hard (slow) turn it out for soft (fast return). this is the rate of return of the shock.
Too slow can cause the bike to understeer exiting turns, run wide.. Try setting the rebound so it returns at about the same rate at which you can push it down, pushing on the seat.

By bobble do you mean the tyre is chewing up ?. this is usually caused by compression damping being too soft.


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popkat
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Re: Suspension question on rebound

Post by popkat »

E.Marquez wrote: Thu Aug 31, 2017 10:03 pm If you have not re sprung for your weight, before you get in to settings, check to see if your just bottom the suspension and thats why it feels too "stiff"
Take a plastic zip tie and place around the fork stanchion. Tighten it tight, and slide to the bottom, the go ride a "normal" rout See where that zip tie is... if it is all the way UP.. the too hard or "stiff" ((There is a joke there someplace)) you are feeling is likely you running out of suspension travel.
You will just chase your tail trying to adjust settings if your not sprung for your weight.
,

I think he's talking about the rear shock.

Your right in that the spring rate needs to be in the right ball park but the zip tie method you mention will only work if you know the measurement for full fork travel. this isn't all about the spring, the fork oil level effects the last third of fork travel, so you can alter this by adding or taking away oil.

Even if your springs are not right you can still adjust your rebound (and compression if you have it) and it will make a difference. The firestorm came standard with fork springs that are way too soft but plenty have ridden around for years like it. fitting stiffer springs makes a bigger difference for sure.

Lastly I've a feeling the original question is probably related to a GSXR1000.


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Miztaziggy
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Re: Suspension question on rebound

Post by Miztaziggy »

Cheers guys

Yeah it's about a GSXR rear shock.

By bobble, I meant the little lump of rubber that builds up on the leading or trailing edge of the tread marks. See below:

Mine was definitely too hard on the rebound (slow) as I could push it down then it took a while to return. My brothers looked fine, but still bobbles the tyre on the tread mark in the same way. I guess we both need to speed up the rebound a little.

The tyre does bobble up on the edges. We've found tyre pressures affect this a lot. Too hard and we get cold tear. A little too hard we just get a very smooth tyre. If it's about right, we get a nice ripple and bobble on the edge. If it's too soft it chews up badly.

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And tyres tend to look like this in terms of the bobbling / ripple when pressures are about right:

Image
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popkat
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Re: Suspension question on rebound

Post by popkat »

The tyre looks good :thumbup:



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2014 CRMC Post classic Superbike champion.
2014 CRMC Post classic senior production champion. On a Suzuki Katana 1100
My bikes, Firestorm, Suzuki GSX-s1000 Katana, VFR800Fi. Projects, 1986 popup Katana, 3 XJ600’s
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